Last data update: May 13, 2024. (Total: 46773 publications since 2009)
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Diarrhea in young children from low-income countries leads to large-scale alterations in intestinal microbiota composition.
Pop M , Walker AW , Paulson J , Lindsay B , Antonio M , Hossain MA , Oundo J , Tamboura B , Mai V , Astrovskaya I , Corrada Bravo H , Rance R , Stares M , Levine MM , Panchalingam S , Kotloff K , Ikumapayi UN , Ebruke C , Adeyemi M , Ahmed D , Ahmed F , Alam MT , Amin R , Siddiqui S , Ochieng JB , Ouma E , Juma J , Mailu E , Omore R , Morris JG , Breiman RF , Saha D , Parkhill J , Nataro JP , Stine OC . Genome Biol 2014 15 (6) R76 BACKGROUND: Diarrheal diseases continue to contribute significantly to morbidity and mortality in infants and young children in developing countries. There is an urgent need to better understand the contributions of novel, potentially uncultured, diarrheal pathogens to severe diarrheal disease, as well as distortions in normal gut microbiota composition that might facilitate severe disease. RESULTS: We use high throughput 16S rRNA gene sequencing to compare fecal microbiota composition in children under five years of age who have been diagnosed with moderate to severe diarrhea (MSD) with the microbiota from diarrhea-free controls. Our study includes 992 children from four low-income countries in West and East Africa, and Southeast Asia. Known pathogens, as well as bacteria currently not considered as important diarrhea-causing pathogens, are positively associated with MSD, and these include Escherichia/Shigella, and Granulicatella species, and Streptococcus mitis/pneumoniae groups. In both cases and controls, there tend to be distinct negative correlations between facultative anaerobic lineages and obligate anaerobic lineages. Overall genus-level microbiota composition exhibit a shift in controls from low to high levels of Prevotella and in MSD cases from high to low levels of Escherichia/Shigella in younger versus older children; however, there was significant variation among many genera by both site and age. CONCLUSIONS: Our findings expand the current understanding of microbiota-associated diarrhea pathogenicity in young children from developing countries. Our findings are necessarily based on correlative analyses and must be further validated through epidemiological and molecular techniques. |
Post-mortem investigation of deaths due to pneumonia in children aged 1-59 months in sub-Saharan Africa and South Asia from 2016 to 2022: an observational study
Mahtab S , Blau DM , Madewell ZJ , Ogbuanu I , Ojulong J , Lako S , Legesse H , Bangura JS , Bassat Q , Mandomando I , Xerinda E , Fernandes F , Varo R , Sow SO , Kotloff KL , Tapia MD , Keita AM , Sidibe D , Onyango D , Akelo V , Gethi D , Verani JR , Revathi G , Scott JAG , Assefa N , Madrid L , Bizuayehu H , Tirfe TT , El Arifeen S , Gurley ES , Islam KM , Alam M , Zahid Hossain M , Dangor Z , Baillie VL , Hale M , Mutevedzi P , Breiman RF , Whitney CG , Madhi SA . Lancet Child Adolesc Health 2024 BACKGROUND: The Child Health and Mortality Prevention Surveillance (CHAMPS) Network programme undertakes post-mortem minimally invasive tissue sampling (MITS), together with collection of ante-mortem clinical information, to investigate causes of childhood deaths across multiple countries. We aimed to evaluate the overall contribution of pneumonia in the causal pathway to death and the causative pathogens of fatal pneumonia in children aged 1-59 months enrolled in the CHAMPS Network. METHODS: In this observational study we analysed deaths occurring between Dec 16, 2016, and Dec 31, 2022, in the CHAMPS Network across six countries in sub-Saharan Africa (Ethiopia, Kenya, Mali, Mozambique, Sierra Leone, and South Africa) and one in South Asia (Bangladesh). A standardised approach of MITS was undertaken on decedents within 24-72 h of death. Diagnostic tests included blood culture, multi-organism targeted nucleic acid amplifications tests (NAATs) of blood and lung tissue, and histopathology examination of various organ tissue samples. An interdisciplinary expert panel at each site reviewed case data to attribute the cause of death and pathogenesis thereof on the basis of WHO-recommended reporting standards. FINDINGS: Pneumonia was attributed in the causal pathway of death in 455 (40·6%) of 1120 decedents, with a median age at death of 9 (IQR 4-19) months. Causative pathogens were identified in 377 (82·9%) of 455 pneumonia deaths, and multiple pathogens were implicated in 218 (57·8%) of 377 deaths. 306 (67·3%) of 455 deaths occurred in the community or within 72 h of hospital admission (presumed to be community-acquired pneumonia), with the leading bacterial pathogens being Streptococcus pneumoniae (108 [35·3%]), Klebsiella pneumoniae (78 [25·5%]), and non-typeable Haemophilus influenzae (37 [12·1%]). 149 (32·7%) deaths occurred 72 h or more after hospital admission (presumed to be hospital-acquired pneumonia), with the most common pathogens being K pneumoniae (64 [43·0%]), Acinetobacter baumannii (19 [12·8%]), S pneumoniae (15 [10·1%]), and Pseudomonas aeruginosa (15 [10·1%]). Overall, viruses were implicated in 145 (31·9%) of 455 pneumonia-related deaths, including 54 (11·9%) of 455 attributed to cytomegalovirus and 29 (6·4%) of 455 attributed to respiratory syncytial virus. INTERPRETATION: Pneumonia contributed to 40·6% of all childhood deaths in this analysis. The use of post-mortem MITS enabled biological ascertainment of the cause of death in the majority (82·9%) of childhood deaths attributed to pneumonia, with more than one pathogen being commonly implicated in the same case. The prominent role of K pneumoniae, non-typable H influenzae, and S pneumoniae highlight the need to review empirical management guidelines for management of very severe pneumonia in low-income and middle-income settings, and the need for research into new or improved vaccines against these pathogens. FUNDING: Bill & Melinda Gates Foundation. |
Mucosal immunity to poliovirus in children 0-15 years of age: A community-based study in Karachi, Pakistan in 2019
Saleem AF , Kazi ZU , Zehra SM , Parkar S , Macklin G , Sifontes G , Mainou BA , Alam M , Lopez Cavestany R , Mach O . J Infect Dis 2024 This study assesses poliovirus type 1 (PV1) immunity in children to inform the contribution of mucosal immunity in and preventing poliovirus circulation. A community-based study was conducted in peri-urban Karachi, Pakistan. Randomly selected children (0-15 years) received oral poliovirus vaccine (OPV) challenge dose. Blood and stool samples were collected at several time points and evaluated for polio-neutralizing antibodies and serotype-specific poliovirus, respectively. 81/589 (14%) children excreted PV1 7 days post-OPV-challenge; 70/81 (86%) were seropositive at baseline. 12/610 (2%) were asymptomatic Wild Poliovirus Type 1 (WPV1) excretors. Most poliovirus excretors had humoral immunity, suggesting mucosal immunity in these children likely waned or never developed. Without mucosal immunity, they are susceptible to poliovirus infection, shedding, and transmission. Asymptomatic WPV1 excretion suggests undetected poliovirus circulation within the community. |
How can global guidelines support sustainable hygiene systems?
Esteves Mills J , Thomas A , Abdalla N , El-Alam R , Al-Shabi K , Ashinyo ME , Bangoura FO , Charles K , Chipungu J , Cole AO , Engebretson B , Goyol K , Grasham CF , Grossi V , Hickling S , Kalandarov S , Ababu AK , Kholmuhammad K , Klaesener-Metzner N , Kugedera Z , Kwakye A , Lee-Llacer A , Maani PP , Makhafola B , Mohamed A , Monirul Alam M , Monse B , Northover H , Palomares A , Patabendi N , Paynter N , Prasad-Gautam O , Panthi SR , Rudge L , Saha S , Salaru I , Saltiel G , Sax L , Shahid MA , Gafur MS , Shrestha S , Szeberényi K , Tidwell JB , Trinies V , Yiha O , Ziganshin R , Gordon B , Cumming O . BMJ Glob Health 2023 8 (10) Hand hygiene is a cost-effective preventive measure to reduce transmission of infectious diseases. Yet, a quarter of the global population lack access to even a basic handwashing facility. | Forthcoming WHO and UNICEF guidelines on hand hygiene in community settings will provide evidence-based recommendations to guide action. | According to consulted future guideline end-users, sustainable implementation of such recommendations to improve hand hygiene requires government-led system-strengthening approaches that build sustainable and resilient national systems. | System-strengthening plans should be underpinned by a comprehensive situational analysis and needs assessment, and monitored on an ongoing basis for course correction where necessary. | Execution of system-strengthening plans should be integrated with existing programmes. | Health sector leadership is required to drive this agenda. |
Lessons learned from identifying clusters of severe acute respiratory infections with influenza sentinel surveillance, Bangladesh, 2009-2020
Islam MA , Hassan MZ , Aleem MA , Akhtar Z , Chowdhury S , Rahman M , Rahman MZ , Ahmmed MK , Mah EMuneer S , Alamgir ASM , Anwar SNR , Alam AN , Shirin T , Rahman M , Davis WW , Mott JA , Azziz-Baumgartner E , Chowdhury F . Influenza Other Respir Viruses 2023 17 (9) e13201 BACKGROUND: We explored whether hospital-based surveillance is useful in detecting severe acute respiratory infection (SARI) clusters and how often these events result in outbreak investigation and community mitigation. METHODS: During May 2009-December 2020, physicians at 14 sentinel hospitals prospectively identified SARI clusters (i.e., ≥2 SARI cases who developed symptoms ≤10 days of each other and lived <30 min walk or <3 km from each other). Oropharyngeal and nasopharyngeal swabs were tested for influenza and other respiratory viruses by real-time reverse transcriptase-polymerase chain reaction (rRT-PCR). We describe the demographic of persons within clusters, laboratory results, and outbreak investigations. RESULTS: Field staff identified 464 clusters comprising 1427 SARI cases (range 0-13 clusters per month). Sixty percent of clusters had three, 23% had two, and 17% had ≥4 cases. Their median age was 2 years (inter-quartile range [IQR] 0.4-25) and 63% were male. Laboratory results were available for the 464 clusters with a median of 9 days (IQR = 6-13 days) after cluster identification. Less than one in five clusters had cases that tested positive for the same virus: respiratory syncytial virus (RSV) in 58 (13%), influenza viruses in 24 (5%), human metapneumovirus (HMPV) in five (1%), human parainfluenza virus (HPIV) in three (0.6%), adenovirus in two (0.4%). While 102/464 (22%) had poultry exposure, none tested positive for influenza A (H5N1) or A (H7N9). None of the 464 clusters led to field deployments for outbreak response. CONCLUSIONS: For 11 years, none of the hundreds of identified clusters led to an emergency response. The value of this event-based surveillance might be improved by seeking larger clusters, with stronger epidemiologic ties or decedents. |
Tackling a global epidemic threat: Nipah surveillance in Bangladesh, 2006-2021
Satter SM , Aquib WR , Sultana S , Sharif AR , Nazneen A , Alam MR , Siddika A , Akther Ema F , Chowdhury KIA , Alam AN , Rahman M , Klena JD , Rahman MZ , Banu S , Shirin T , Montgomery JM . PLoS Negl Trop Dis 2023 17 (9) e0011617 Human Nipah virus (NiV) infection is an epidemic-prone disease and since the first recognized outbreak in Bangladesh in 2001, human infections have been detected almost every year. Due to its high case fatality rate and public health importance, a hospital-based Nipah sentinel surveillance was established in Bangladesh to promptly detect Nipah cases and respond to outbreaks at the earliest. The surveillance has been ongoing till present. The hospital-based sentinel surveillance was conducted at ten strategically chosen tertiary care hospitals distributed throughout Bangladesh. The surveillance staff ensured that routine screening, enrollment, data, and specimen collection from suspected Nipah cases were conducted daily. The specimens were then processed and transported to the reference laboratory of Institute of Epidemiology, Disease Control and Research (IEDCR) and icddr,b for confirmation of diagnosis through serology and molecular detection. From 2006 to 2021, through this hospital-based surveillance platform, 7,150 individuals were enrolled and tested for Nipah virus. Since 2001, 322 Nipah infections were identified in Bangladesh, 75% of whom were laboratory confirmed cases. Half of the reported cases were primary cases (162/322) having an established history of consuming raw date palm sap (DPS) or tari (fermented date palm sap) and 29% were infected through person-to-person transmission. Since the initiation of surveillance, 68% (218/322) of Nipah cases from Bangladesh have been identified from various parts of the country. Fever, vomiting, headache, fatigue, and increased salivation were the most common symptoms among enrolled Nipah patients. Till 2021, the overall case fatality rate of NiV infection in Bangladesh was 71%. This article emphasizes that the overall epidemiology of Nipah virus infection in Bangladesh has remained consistent throughout the years. This is the only systematic surveillance to detect human NiV infection globally. The findings from this surveillance have contributed to early detection of NiV cases in hospital settings, understanding of Nipah disease epidemiology, and have enabled timely public health interventions for prevention and containment of NiV infection. Although we still have much to learn regarding the transmission dynamics and risk factors of human NiV infection, surveillance has played a significant role in advancing our knowledge in this regard. |
Provider adherence to clinical care recommendations for infants and children who died in seven low- and middle-income countries in the Child Health and Mortality Prevention Surveillance (CHAMPS) network
Rees CA , Igunza KA , Madewell ZJ , Akelo V , Onyango D , El Arifeen S , Gurley ES , Hossain MZ , Rahman A , Alam M , Scott JAG , Assefa N , Madrid L , Belachew A , Leulseged H , Kotloff KL , Sow SO , Tapia MD , Keita AM , Sidibe D , Sitoe A , Varo R , Ajanovic S , Bassat Q , Mandomando I , Tippett Barr BA , Ogbuanu I , Cain CJ , Bassey IA , Luke R , Gassama K , Madhi S , Dangor Z , Mahtab S , Velaphi S , du Toit J , Mutevedzi PC , Blau DM , Breiman RF , Whitney CG . EClinicalMedicine 2023 63 102198 BACKGROUND: Most childhood deaths globally are considered preventable through high-quality clinical care, which includes adherence to clinical care recommendations. Our objective was to describe adherence to World Health Organization recommendations for the management of leading causes of death among children. METHODS: We conducted a retrospective, descriptive study examining clinical data for children aged 1-59 months who were hospitalized and died in a Child Health and Mortality Prevention Surveillance (CHAMPS) catchment, December 2016-June 2021. Catchment areas included: Baliakandi and Faridpur, Bangladesh; Kersa, Haramaya, and Harar, Ethiopia; Kisumu and Siaya, Kenya; Bamako, Mali; Manhiça and Quelimane, Mozambique; Makeni, Sierra Leone; Soweto, South Africa. We reviewed medical records of those who died from lower respiratory tract infections, sepsis, malnutrition, malaria, and diarrheal diseases to determine the proportion who received recommended treatments and compared adherence by hospitalization duration. FINDINGS: CHAMPS enrolled 460 hospitalized children who died from the leading causes (median age 12 months, 53.0% male). Median hospital admission was 31 h. There were 51.0% (n = 127/249) of children who died from lower respiratory tract infections received supplemental oxygen. Administration of intravenous fluids for sepsis (15.9%, n = 36/226) and supplemental feeds for malnutrition (14.0%, n = 18/129) were uncommon. There were 51.4% (n = 55/107) of those who died from malaria received antimalarials. Of the 80 children who died from diarrheal diseases, 76.2% received intravenous fluids. Those admitted for ≥24 h more commonly received antibiotics for lower respiratory tract infections and sepsis, supplemental feeds for malnutrition, and intravenous fluids for sepsis than those admitted <24 h. INTERPRETATION: Provision of recommended clinical care for leading causes of death among young children was suboptimal. Further studies are needed to understand the reasons for deficits in clinical care recommendation adherence. FUNDING: Bill & Melinda Gates Foundation. |
Stillbirths and neonatal deaths caused by group B streptococcus in Africa and South Asia identified through Child Health and Mortality Prevention Surveillance (CHAMPS)
Mahtab S , Madewell ZJ , Madhi SA , Wise A , Swart PJ , Velaphi S , Mandomando I , Bramugy J , Mabunda R , Xerinda E , Scott AG , Assefa N , Madrid L , Bweihun M , Temesgen F , Onyango D , Akelo V , Oliech R , Otieno P , Verani JR , Arifeen SE , Gurley ES , Alam M , Rahman A , Hossain MZ , Sow S , Kotloff K , Tapia M , Keita AM , Sanogo D , Ogbuanu I , Ojulong J , Lako S , Ita O , Kaluma E , Wilson T , Mutevedzi P , Barr BAT , Whitney CG , Blau DM , Bassat Q . Open Forum Infect Dis 2023 10 (9) ofad356 BACKGROUND: Invasive Group B Streptococcus (GBS) is a common cause of early-onset neonatal sepsis and is also associated with stillbirth. This study aimed to determine the proportion of stillborn infants and infants who died between 0 and 90 days attributable to GBS using postmortem minimally invasive tissue sampling (MITS) in 7 low- and middle-income countries (LMICs) participating in Child Health and Mortality Prevention Surveillance (CHAMPS). METHODS: Deaths that occurred between December 2016 and December 2021 were investigated with MITS, including culture for bacteria of blood and cerebrospinal fluid (CSF), multipathogen polymerase chain reaction on blood, CSF, and lung tissue and histopathology of lung, liver, and brain. Data collection included clinical record review and verbal autopsy. Expert panels reviewed all information and assigned causes of death. RESULTS: We evaluated 2966 deaths, including stillborn infants (n = 1322), infants who died during first day of life (0 to <24 hours, n = 597), early neonatal deaths (END) (1 day to <7 days; END; n = 593), and deaths from 7 to 90 days (n = 454). Group B Streptococcus was determined to be in the causal pathway of death for 2.7% of infants (79 of 2, 966; range, 0.3% in Sierra Leone to 7.2% in South Africa), including 2.3% (31 of 1322) of stillbirths, 4.7% (28 of 597) 0 to <24 hours, 1.9% (11 of 593) END, and 2.0% (9 of 454) of deaths from 7 to 90 days of age. Among deaths attributed to GBS with birth weight data available, 61.9% (39 of 63) of decedents weighed <2500 grams at birth. Group B Streptococcus sepsis was the postmortem diagnosis for 100% (31 of 31) of stillbirths. For deaths <90 days, postmortem diagnoses included GBS sepsis (83.3%, 40 of 48), GBS meningitis (4.2%, 2 of 48), and GBS pneumonia (2.1%, 1 of 48). CONCLUSIONS: Our study reveals significant heterogeneity in the contribution of invasive GBS disease to infant mortality across different countries, emphasizing the need for tailored prevention strategies. Moreover, our findings highlight the substantial impact of GBS on stillbirths, shedding light on a previously underestimated aspect in LMICs. |
Progress toward poliomyelitis eradication - Pakistan, January 2022-June 2023
Mbaeyi C , Baig S , Safdar RM , Khan Z , Young H , Jorba J , Wadood ZM , Jafari H , Alam MM , Franka R . MMWR Morb Mortal Wkly Rep 2023 72 (33) 880-885 Since the establishment of the Global Polio Eradication Initiative in 1988, Pakistan remains one of only two countries (along with Afghanistan) with continued endemic transmission of wild poliovirus (WPV). This report describes Pakistan's progress toward polio eradication during January 2022-June 2023. During 2022, Pakistan reported 20 WPV type 1 (WPV1) cases, all of which occurred within a small geographic area encompassing three districts in south Khyber Pakhtunkhwa. As of June 23, only a single WPV1 case from Bannu district in Khyber Pakhtunkhwa province has been reported in 2023, compared with 13 cases during the same period in 2022. In addition, 11 WPV1 isolates have been reported from various environmental surveillance (ES) sewage sampling sites to date in 2023, including in Karachi, the capital of the southern province of Sindh. Substantial gaps remain in the quality of supplementary immunization activities (SIAs), especially in poliovirus reservoir areas. Despite the attenuation and apparently limited geographic scope of poliovirus circulation in Pakistan, the isolation of WPV1 from an ES site in Karachi is cause for concern about the actual geographic limits of transmission. Interrupting WPV1 transmission will require meticulous tracking and sustained innovative efforts to vaccinate children who are regularly missed during SIAs and rapidly responding to any new WPV1 isolations. |
Estimating typhoid incidence from community-based serosurveys: A multicohort study in Bangladesh, Nepal, Pakistan and Ghana (preprint)
Aiemjoy K , Seidman JC , Saha S , Munira SJ , Islam Sajib MS , Sium SMA , Sarkar A , Alam N , Zahan FN , Kabir MS , Tamrakar D , Vaidya K , Shrestha R , Shakya J , Katuwal N , Shrestha S , Yousafzai MT , Iqbal J , Dehraj IF , Ladak Y , Maria N , Adnan M , Pervaiz S , Carter AS , Longley AT , Fraser C , Ryan ET , Nodoushani A , Fasano A , Leonard MM , Kenyon V , Bogoch II , Jeon HJ , Haselbeck A , Park SE , Zellweger RM , Marks F , Owusu-Dabo E , Adu-Sarkodie Y , Owusu M , Teunis P , Luby SP , Garrett DO , Qamar FN , Saha SK , Charles RC , Andrews JR . medRxiv 2022 2021.10.20.21265277 Background The incidence of enteric fever, an invasive bacterial infection caused by typhoidal Salmonellae, is largely unknown in regions lacking blood culture surveillance. New serologic markers have proven accurate in diagnosing enteric fever, but whether they could be used to reliably estimate population-level incidence is unknown.Methods We collected longitudinal blood samples from blood culture-confirmed enteric fever cases enrolled from surveillance studies in Bangladesh, Nepal, Pakistan, and Ghana and conducted cross-sectional serosurveys in the catchment areas of each surveillance site. We used ELISAs to measure quantitative IgA and IgG antibody responses to Hemolysin E (HlyE) and S. Typhi lipopolysaccharide (LPS). We used Bayesian hierarchical models to fit two-phase power-function decay models to the longitudinal antibody responses among enteric fever cases and used the joint distributions of the peak antibody titers and decay rate to estimate population-level incidence rates from cross-sectional serosurveys.Findings The longitudinal antibody kinetics for all antigen-isotypes were similar across countries and did not vary by clinical severity. The seroincidence of typhoidal Salmonella infection among children <5 years ranged between 58.5 per 100 person-years (95% CI: 42.1 - 81.4) in Dhaka, Bangladesh to 6.6 (95% CI: 4.3-9.9) in Kavrepalanchok, Nepal, and followed the same rank order as clinical incidence estimates.Interpretation The approach described here has the potential to expand the geographic scope of typhoidal Salmonella surveillance and generate incidence estimates that are comparable across geographic regions and time.Funding This work was supported by the Bill and Melinda Gates Foundation (INV-000572).Evidence before this study Previous studies have identified serologic responses to two antigens (Hemolysin E [HlyE] and Salmonella lipopolysaccharide [LPS]) as promising diagnostic markers of acute typhoidal Salmonella infection. We reviewed the evidence for seroepidemiology tools for enteric fever available as of November 01, 2021, by searching the National Library of Medicine article database and medRxiv for preprint publications, published in English, using the terms “enteric fever”, “typhoid fever”, “Salmonella Typhi”, “Salmonella Paratyphi”, “typhoidal Salmonella”, “Hemolysin E”, “Salmonella lipopolysaccharide”, “seroconversion”, “serosurveillance”, “seroepidemiology”, “seroprevalence” and “seropositivity.” We found no studies using HlyE or LPS as markers to measure the incidence or prevalence of enteric fever in a population. Anti-Vi IgG responses were used as a marker of population seroprevalence in cross-sectional studies conducted in South Africa, Fiji, and Nepal, but were not used to calculate population-based incidence estimates.Added value of this study We developed and validated a method to estimate typhoidal Salmonella incidence in cross-sectional population samples using antibody responses measured from dried blood spots. First, using longitudinal dried blood spots collected from over 1400 blood culture-confirmed cases in four countries, we modeled the longitudinal dynamics of antibody responses for up to two years following infection, accounting for heterogeneity in antibody responses and age-dependence. We found that longitudinal antibody responses were highly consistent across four countries on two continents and did not differ by clinical severity. We then used these antibody kinetic parameters to estimate incidence in population-based samples in six communities across the four countries, where concomitant population-based incidence was measured using blood cultures. Seroincidence estimates were much higher than blood-culture-based case estimates across all six sites, suggestive of a high incidence of asymptomatic or unrecognized infections. Still, the rank order of seroincidence and culture-based incidence rates were the same, with the highest rates in Bangladesh and lowest in Ghana.Implications of all the available evidence Many a -risk low- and middle-income countries lack data on typhoid incidence needed to inform and evaluate vaccine introduction. Even in countries where incidence estimates are available, data are typically geographically and temporally sparse due to the resources necessary to initiate and sustain blood culture surveillance. We found that typhoidal Salmonella infection incidence can be estimated from community-based serosurveys using dried blood spots, representing an efficient and scalable approach for generating the typhoid burden data needed to inform typhoid control programs in resource-constrained settings.Competing Interest StatementThe authors have declared no competing interest.Funding StatementThis study was funded by th eBill and Melinda Gates Foundation (grant INV-000572)Author DeclarationsI confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.YesThe details of the IRB/oversight body that provided approval or exemption for the research described are given below:Institutional Review Boards in the United States (Centers for Disease Control and Prevention; Stanford University Institutional Review Board), Bangladesh (Bangladesh Institute of Child Health Ethical Review Committee), Nepal (Nepal Health Research Council Ethical Review Board), Pakistan (AKU Ethic Review Committee and Pakistan National Bioethics Committee), Korea (International Vaccine Institute IRB), Belgium (Institute of Tropical Medicine Antwerp Institutional Review Board) and Ghana (Komfo Anokye Teaching Hospital, Committee on Human Research, Publication and Ethics) approved the study forms and protocols.I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.YesI understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).YesI have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.YesAll data produced in the present study are available upon reasonable request to the authors |
Population analysis of Vibrio cholerae in aquatic reservoirs reveals a novel sister species (Vibrio paracholerae sp. nov.) with a history of association with human infections (preprint)
Islam MT , Nasreen T , Kirchberger P , Liang KYH , Orata FD , Johura FT , Im MS , Tarr CL , Alam M , Boucher YF . bioRxiv 2021 2021.05.05.442690 Most efforts to understand the biology of Vibrio cholerae have focused on a single group, the pandemic-generating lineage harbouring the strains responsible for all known cholera pandemics. Consequently, little is known about the diversity of this species in its native aquatic environment. To understand the differences in the V. cholerae populations inhabiting in regions with varying history of cholera cases and how that might influence the abundance of pandemic strains, a comparative analysis of population composition was performed. Little overlap was found in lineage compositions between those in Dhaka (cholera endemic) located in the Ganges delta, and of Falmouth (no known history of cholera), a small coastal town on the US East Coast. The most striking difference was the presence of a group of related lineages at high abundance in Dhaka which was completely absent from Falmouth. Phylogenomic analysis revealed that these lineages form a cluster at the base of the phylogeny of V. cholerae species, sufficiently differentiated genetically and phenotypically to form a novel species. Strains from this species have been anecdotally isolated from around the world and were isolated as early as 1916 from a British soldier in Egypt suffering from choleraic diarrhoea. In 1935 Gardner and Venkatraman unofficially referred to a member of this group as Vibrio paracholerae. In recognition of this earlier designation, we propose the name Vibrio paracholerae, sp. nov. for this bacterium. Genomic analysis suggests a link with human populations for this novel species and substantial interaction with its better-known sister species.Importance Cholera continues to remain a major public health threat around the globe. Understanding the ecology, evolution and environmental adaptation of the causative agent Vibrio cholerae and tracking the emergence of novel lineages with pathogenic potential are essential to combat the problem. In this study, we investigated the population dynamics of Vibrio cholerae in an inland locality which is known as endemic for cholera and compared with that of a cholera free coastal location. We found the consistent presence of the pandemic generating V. cholerae in cholera-endemic Dhaka and an exclusive presence of a lineage phylogenetically distinct from other V. cholerae. Our study suggests that this lineage represents a novel species having pathogenic potential and a human link to its environmental abundance. The possible association with human population, co-existence and interaction with toxigenic V. cholerae in the natural environment make this potential human pathogen an important subject for future studies.Competing Interest StatementThe authors have declared no competing interest. |
Insecticide resistance status of Aedes aegypti in Bangladesh (preprint)
Al-Amin HM , Johora FT , Irish SR , Hossainey MRH , Vizcaino L , Paul KK , Khan WA , Haque R , Alam MS , Lenhart A . bioRxiv 2020 2020.07.31.231076 Background Arboviral diseases including dengue and chikungunya are major public health concern in Bangladesh, with unprecedented levels of transmission reported in recent years. The primary approach to control these diseases is control of Aedes aegypti using pyrethroid insecticides. Although chemical control is long-practiced, no comprehensive analysis of Ae. aegypti susceptibility to insecticides has previously been conducted. This study aimed to determine the insecticide resistance status of Ae. aegypti in Bangladesh and investigate the role of detoxification enzymes and altered target site sensitivity as resistance mechanisms.Methods Aedes eggs were collected using ovitraps from five districts across the country and in eight neighborhoods of the capital city Dhaka from August to November 2017. CDC bottle bioassays were conducted for permethrin, deltamethrin, malathion, and bendiocarb using 3-5-day old F0-F2 non-blood fed female mosquitoes. Biochemical assays were conducted to detect metabolic resistance mechanisms and real-time PCR was performed to determine the frequencies of the knockdown resistance (kdr) mutations Gly1016, Cys1534, and Leu410.Results High levels of resistance to permethrin were detected in all Ae. aegypti populations, with mortality ranging from 0 – 14.8% at the diagnostic dose. Substantial resistance continued to be detected against higher (2X) doses of permethrin (5.1 – 44.4% mortality). Susceptibility to deltamethrin and malathion varied between populations while complete susceptibility to bendiocarb was observed in all populations. Significantly higher levels of esterase and oxidase activity were detected in most of the test populations as compared to the susceptible reference Rockefeller strain. A significant association was detected between permethrin resistance and the presence of Gly1016 and Cys1534 homozygotes. The frequency of kdr alleles varied across the Dhaka populations, and Leu410 was not detected in any of the tested populations.Conclusions The detection of widespread pyrethroid resistance and multiple mechanisms highlights the urgency for implementing alternate Ae. aegypti control strategies. In addition, implementing routine monitoring of insecticide resistance in Ae. aegypti in Bangladesh will lead to a greater understanding of susceptibility trends over space and time, thereby enabling the development of improved control strategies.Competing Interest StatementThe authors have declared no competing interest.AChEacetylcholine esterase;BIBreteau Index;β-ESTβ esterase;CIconfidence intervals;DDTdichlorodiphenyltrichloroethane;DTNBdithio-bis-2-nitrobenzoic acid;GSTsglutathione S-transferases;HWEHardy-Weinberg equilibrium;IRSindoor residual spraying;IACHEinsensitive acetylcholine esterase;icddr,bInternational Centre for Diarrhoeal Disease Research, Bangladesh;kdrknockdown resistance:LLINslong-lasting insecticidal nets:MFOsmixed-function oxidases;ODoptical density;ROCKRockefeller;CDCU.S. Centers for Disease Control and Prevention;VGSCvoltage-gated sodium channel;WHOWorld Health Organization |
A Vibrio cholerae Core Genome Multilocus Sequence Typing Scheme to Facilitate the Epidemiological Study of Cholera (preprint)
Liang KYH , Orata FD , Islam MT , Nasreen T , Alam M , Tarr CL , Boucher YF . bioRxiv 2020 2020.01.27.919118 Core genome multilocus sequence typing (cgMLST) has gained popularity in recent years in epidemiological research and subspecies level classification. cgMLST retains the intuitive nature of traditional MLST but offers much greater resolution by utilizing significantly larger portions of the genome. Here, we introduce a cgMLST scheme for Vibrio cholerae, a bacterium abundant in marine and freshwater environments and the etiologic agent of cholera. A set of 2,443 core genes ubiquitous in V. cholerae were used to analyze a comprehensive dataset of 1,262 clinical and environmental strains collected from 52 countries, including 65 newly sequenced genomes in this study. We established a sublineage threshold based on 133 allelic differences that creates clusters nearly identical to traditional MLST types, providing backwards compatibility to new cgMLST classifications. We also defined an outbreak threshold based on seven allelic differences that is capable of identifying strains from the same outbreak and closely related isolates which could give clues on outbreak origin. Using cgMLST, we confirmed the South Asian origin of modern epidemics and identified clustering affinity among sublineages of environmental isolates from the same geographic origin. Advantages of this method are highlighted by direct comparison with existing classification methods, such as MLST and single nucleotide polymorphism-based methods. cgMLST outperforms all existing methods in terms of resolution, standardization, and ease-of-use. We anticipate this scheme will serve as a basis for a universally applicable and standardized classification system for V. cholerae research and epidemiological surveillance in the future. This cgMLST scheme is publicly available on PubMLST (https://pubmlst.org/vcholerae/).IMPORTANCE Toxigenic Vibrio cholerae of the O1 and O139 serogroups are the causative agent of cholera, an acute diarrheal disease that plagued the world for centuries, if not millennia. Here, we introduce a core genome multilocus sequence typing (cgMLST) scheme for V. cholerae. Using cgMLST, we established an outbreak threshold that can efficiently identify outbreak related strains and potential sources of introduction. We also defined a sublineage threshold that is similar to traditional MLST sequence type which will provide context to this new typing method by relating it to previous MLST results. cgMLST outperforms all existing methods in terms of resolution, standardization, and ease-of-use, making this scheme the most suitable method for V. cholerae typing and surveillance worldwide. |
Vibrio tarriae sp. nov., a novel member of the Cholerae clade isolated from across the United States (preprint)
Islam MT , Liang K , Orata FD , Im MS , Alam M , Lee CC , Boucher YF . bioRxiv 2022 17 A number of bacteria with close resemblance to Vibrio cholerae has been isolated over the years by the Centers for Disease Control and Prevention (CDC), which could not be assigned a proper taxonomic designation based on preliminary identification methods. Nine such isolates have been found to share 16S rRNA gene identity exceeding 99% with V. cholerae, yet DNA-DNA hybridization (60.4-62.1%) and average nucleotide identity values (94.4-95.1%) were below the species cut-off, indicating a potentially novel species. Phylogenetic analysis of core genomes places this group of isolates in a monophyletic clade, within the "Cholerae clade," but distinct from any other species. Extensive phenotypic characterization reveals unique biochemical properties that distinguish this novel species from V. cholerae. Comparative genomic analysis reveals a unique set of siderophore genes, suggesting that iron acquisition strategies could be vital for the divergence of the novel species from a common ancestor with V. cholerae. Based on genetic, phylogenetic, and phenotypic differences observed, we propose these isolates represent a novel species of the genus Vibrio, for which the name Vibrio tarriae sp. nov. is proposed. Strain 2521-89 (= DSM 112461 = CCUG 75318), isolated from lake water, is the type strain. Copyright The copyright holder for this preprint is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. All rights reserved. No reuse allowed without permission. |
Causes of death among infants and children in the Child Health and Mortality Prevention Surveillance (CHAMPS) Network
Bassat Q , Blau DM , Ogbuanu IU , Samura S , Kaluma E , Bassey IA , Sow S , Keita AM , Tapia MD , Mehta A , Kotloff KL , Rahman A , Islam KM , Alam M , El Arifeen S , Gurley ES , Baillie V , Mutevedzi P , Mahtab S , Thwala BN , Tippett Barr BA , Onyango D , Akelo V , Rogena E , Onyango P , Omore R , Mandomando I , Ajanovic S , Varo R , Sitoe A , Duran-Frigola M , Assefa N , Scott JAG , Madrid L , Tesfaye T , Dessie Y , Madewell ZJ , Breiman RF , Whitney CG , Madhi SA . JAMA Netw Open 2023 6 (7) e2322494 IMPORTANCE: The number of deaths of children younger than 5 years has been steadily decreasing worldwide, from more than 17 million annual deaths in the 1970s to an estimated 5.3 million in 2019 (with 2.8 million deaths occurring in those aged 1-59 months [53% of all deaths in children aged <5 years]). More detailed characterization of childhood deaths could inform interventions to improve child survival. OBJECTIVE: To describe causes of postneonatal child deaths across 7 mortality surveillance sentinel sites in Africa and Asia. DESIGN, SETTING, AND PARTICIPANTS: The Child Health and Mortality Prevention Surveillance (CHAMPS) Network conducts childhood mortality surveillance in sub-Saharan Africa and South Asia using innovative postmortem minimally invasive tissue sampling (MITS). In this cross-sectional study, MITS was conducted in deceased children aged 1 to 59 months at 7 sites in sub-Saharan Africa and South Asia from December 3, 2016, to December 3, 2020. Data analysis was conducted between October and November 2021. MAIN OUTCOMES AND MEASURES: The expert panel attributed underlying, intermediate, and immediate conditions in the chain of events leading to death, based on histopathologic analysis, microbiological diagnostics, clinical data, and verbal autopsies. RESULTS: In this study, MITS was performed in 632 deceased children (mean [SD] age at death, 1.3 [0.3] years; 342 [54.1%] male). The 6 most common underlying causes of death were malnutrition (104 [16.5%]), HIV (75 [11.9%]), malaria (71 [11.2%]), congenital birth defects (64 [10.1%]), lower respiratory tract infections (LRTIs; 53 [8.4%]), and diarrheal diseases (46 [7.2%]). When considering immediate causes only, sepsis (191 [36.7%]) and LRTI (129 [24.8%]) were the 2 dominant causes. An infection was present in the causal chain in 549 of 632 deaths (86.9%); pathogens most frequently contributing to infectious deaths included Klebsiella pneumoniae (155 of 549 infectious deaths [28.2%]; 127 [81.9%] considered nosocomial), Plasmodium falciparum (122 of 549 [22.2%]), and Streptococcus pneumoniae (109 of 549 [19.9%]). Other organisms, such as cytomegalovirus (57 [10.4%]) and Acinetobacter baumannii (39 [7.1%]; 35 of 39 [89.7%] considered nosocomial), also played important roles. For the top underlying causes of death, the median number of conditions in the chain of events leading to death was 3 for malnutrition, 3 for HIV, 1 for malaria, 3 for congenital birth defects, and 1 for LRTI. Expert panels considered 494 of 632 deaths (78.2%) preventable and 26 of 632 deaths (4.1%) preventable under certain conditions. CONCLUSIONS AND RELEVANCE: In this cross-sectional study investigating causes of child mortality in the CHAMPS Network, results indicate that, in these high-mortality settings, infectious diseases continue to cause most deaths in infants and children, often in conjunction with malnutrition. These results also highlight opportunities for action to prevent deaths and reveal common interaction of various causes in the path toward death. |
Development of an international glossary for clinical guidelines collaboration
Christensen RE , Yi MD , Kang BY , Ibrahim SA , Anvery N , Dirr M , Adams S , Amer YS , Bisdorff A , Bradfield L , Brown S , Earley A , Fatheree LA , Fayoux P , Getchius T , Ginex P , Graham A , Green CR , Gresele P , Hanson H , Haynes N , Hegedüs L , Hussein H , Jakhmola P , Kantorova L , Krishnasamy R , Krist A , Landry G , Lease ED , Ley L , Marsden G , Meek T , Meremikwu M , Moga C , Mokrane S , Mujoomdar A , Newton S , O'Flynn N , Perkins GD , Smith EJ , Prematunge C , Rychert J , Saraco M , Schünemann HJ , Senerth E , Sinclair A , Shwayder J , Stec C , Tanni S , Taske N , Temple-Smolkin RL , Thomas L , Thomas S , Tonnessen B , Turner AS , Van Dam A , van Doormaal M , Wan YL , Ventura CB , McFarlane E , Morgan RL , Ogunremi T , Alam M . J Clin Epidemiol 2023 158 84-91 OBJECTIVE: Clinical practice guidelines are often created through collaboration among organizations. Use of inconsistent terminology may cause poor communication and delays. This study aimed to develop a glossary of terms related to collaboration in guideline development. STUDY DESIGN AND SETTING: A literature review of collaborative guidelines was performed to develop an initial list of terms related to guideline collaboration. The list of terms was presented to the members of the Guideline International Network Guidelines Collaboration Working Group, who provided presumptive definitions for each term and proposed additional terms to be included. The revised list was subsequently reviewed by an international, multidisciplinary panel of expert stakeholders. Recommendations received during this pre-Delphi review were implemented to augment an initial draft glossary. The glossary was then critically evaluated and refined through two rounds of Delphi surveys and a virtual consensus meeting with all panel members as Delphi participants. RESULTS: Forty-nine experts participated in the pre-Delphi survey and 44 participated in the two-round Delphi process. Consensus was reached for 37 terms and definitions. CONCLUSION: Uptake and utilization of this guideline collaboration glossary by key organizations and stakeholder groups may facilitate collaboration among guideline-producing organizations by improving communication, minimizing conflicts, and increasing guideline development efficiency. |
Causes of death identified in neonates enrolled through Child Health and Mortality Prevention Surveillance (CHAMPS), December 2016 -December 2021
Mahtab S , Madhi SA , Baillie VL , Els T , Thwala BN , Onyango D , Tippet-Barr BA , Akelo V , Igunza KA , Omore R , Arifeen SE , Gurley ES , Alam M , Chowdhury AI , Rahman A , Bassat Q , Mandomando I , Ajanovic S , Sitoe A , Varo R , Sow SO , Kotloff KL , Badji H , Tapia MD , Traore CB , Ogbuanu IU , Bunn J , Luke R , Sannoh S , Swarray-Deen A , Assefa N , Scott JAG , Madrid L , Marami D , Fentaw S , Diaz MH , Martines RB , Breiman RF , Madewell ZJ , Blau DM , Whitney CG . PLOS Glob Public Health 2023 3 (3) e0001612 Each year, 2.4 million children die within their first month of life. Child Health and Mortality Prevention Surveillance (CHAMPS) established in 7 countries aims to generate accurate data on why such deaths occur and inform prevention strategies. Neonatal deaths that occurred between December 2016 and December 2021 were investigated with MITS within 24-72 hours of death. Testing included blood, cerebrospinal fluid and lung cultures, multi-pathogen PCR on blood, CSF, nasopharyngeal swabs and lung tissue, and histopathology examination of lung, liver and brain. Data collection included clinical record review and family interview using standardized verbal autopsy. The full set of data was reviewed by local experts using a standardized process (Determination of Cause of Death) to identify all relevant conditions leading to death (causal chain), per WHO recommendations. For analysis we stratified neonatal death into 24-hours of birth, early (1-<7 days) and late (7-<28 days) neonatal deaths. We analyzed 1458 deaths, 41% occurring within 24-hours, 41% early and 18% late neonatal deaths. Leading underlying causes of death were complications of intrapartum events (31%), complications of prematurity (28%), infections (17%), respiratory disorders (11%), and congenital malformations (8%). In addition to the underlying cause, 62% of deaths had additional conditions and 14% had ≥3 other conditions in the causal chain. The most common causes considering the whole causal chain were infection (40%), prematurity (32%) and respiratory distress syndrome (28%). Common maternal conditions linked to neonatal death were maternal hypertension (10%), labour and delivery complications (8%), multiple gestation (7%), placental complications (6%) obstructed labour and chorioamnionitis (5%, each). CHAMPS' findings showing the full causal chain of events that lead to death, in addition to maternal factors, highlights the complexities involved in each death along with the multiple opportunities for prevention. Highlighting improvements to prenatal and obstetric care and infection prevention are urgently needed in high-mortality settings. |
Insecticide resistance compromises the control of Aedes aegypti in Bangladesh.
Al-Amin HM , Gyawali N , Graham M , Alam MS , Lenhart A , Hugo LE , Rašić G , Beebe NW , Devine GJ . Pest Manag Sci 2023 79 (8) 2846-2861 BACKGROUND: With no effective drugs or widely available vaccines, dengue control in Bangladesh is dependent on targeting the primary vector Aedes aegypti with insecticides and larval source management. Despite these interventions, the dengue burden is increasing in Bangladesh, and the country experienced its worst outbreak in 2019 with 101,354 hospitalized cases. This may be partially facilitated by the presence of intense insecticide resistance in vector populations. Here, we describe the intensity and mechanisms of resistance to insecticides commonly deployed against Ae. aegypti in Dhaka, Bangladesh. RESULTS: Dhaka Ae. aegypti colonies exhibited high-intensity resistance to pyrethroids. Using CDC bottle assays, we recorded 2 - 24% mortality (recorded at 24 hours) to permethrin and 48 - 94% mortality to deltamethrin, at 10x the diagnostic dose. Bioassays conducted using insecticide-synergist combinations suggested that metabolic mechanisms were contributing to pyrethroid resistance, specifically multi-function oxidases, esterases, and glutathione S-transferases. In addition, kdr alleles were detected, with a high frequency (78-98%) of homozygotes for the V1016G mutation. A large proportion (≤ 74%) of free-flying and resting mosquitoes from Dhaka colonies survived exposure to standard applications of pyrethroid aerosols in an experimental free-flight room. Although that exposure affected Ae. aegypti's immediate host-seeking behavior, the effect was transient in surviving mosquitoes. CONCLUSION: The intense resistance characterized in this study is likely compromising the operational effectiveness of pyrethroids against Ae. aegypti in Dhaka. Switching to alternative chemical classes may offer a medium-term solution, but ultimately a more sustainable and effective approach to controlling dengue vectors is required. This article is protected by copyright. All rights reserved. |
Progress toward poliomyelitis eradication - Pakistan, January 2021-July 2022
Mbaeyi C , Baig S , Safdar MR , Khan Z , Young H , Jorba J , Wadood ZM , Jafari H , Alam MM , Franka R . MMWR Morb Mortal Wkly Rep 2022 71 (42) 1313-1318 After reporting a single wild poliovirus (WPV) type 1 (WPV1) case in 2021, Pakistan reported 14 cases during April 1-July 31, 2022. Pakistan and Afghanistan are the only countries where endemic WPV transmission has never been interrupted (1). In its current 5-year strategic plan, the Global Polio Eradication Initiative (GPEI) has set a goal of interrupting all WPV1 transmission by the end of 2023 (1-3). The reemergence of WPV cases in Pakistan after 14 months with no case detection has uncovered transmission in southern Khyber Pakhtunkhwa province, the most historically challenging area. This report describes Pakistan's progress toward polio eradication during January 2021-July 2022 and updates previous reports (4,5). As of August 20, 2022, all but one of the 14 WPV1 cases in Pakistan during 2022 have been reported from North Waziristan district in Khyber Pakhtunkhwa. In underimmunized populations, excretion of vaccine virus can, during a period of 12-18 months, lead to reversion to neurovirulence, resulting in circulating vaccine-derived polioviruses (cVDPVs), which can cause paralysis and outbreaks. An outbreak of cVDPV type 2 (cVDPV2), which began in Pakistan in 2019, has been successfully contained; the last case occurred in April 2021 (1,6). Despite program improvements, 400,000-500,000 children continue to be missed during nationwide polio supplementary immunization activities (SIAs),* and recent isolation of poliovirus from sewage samples collected in other provinces suggests wider WPV1 circulation during the ongoing high transmission season. Although vaccination efforts have been recently complicated by months of flooding during the summer of 2022, to successfully interrupt WPV1 transmission in the core reservoirs in southern Khyber Pakhtunkhwa and reach the GPEI goal, emphasis should be placed on further improving microplanning and supervision of SIAs and on systematic tracking and vaccination of persistently missed children in these reservoir areas of Pakistan. |
Vibrio tarriae sp. nov., a novel member of the Cholerae clade.
Islam MT , Liang K , Orata FD , Im MS , Alam M , Lee CC , Boucher YF . Int J Syst Evol Microbiol 2022 72 (9) A number of bacteria with close resemblance to Vibrio cholerae have been isolated over the years by the Centres for Disease Control and Prevention (CDC), which could not be assigned a proper taxonomic designation on the basis of the results from preliminary identification methods. Nine such isolates have been found to share 16S rRNA gene identity exceeding 99 % with V. cholerae, yet DNA-DNA hybridization (60.4-62.1 %) and average nucleotide identity values (94.4-95.1 %) were below the species cut-off, indicating a potentially novel species. Phylogenetic analysis of core genomes places this group of isolates in a monophyletic clade, within the 'Cholerae clade', but distinct from any other species. Extensive phenotypic characterization reveals unique biochemical properties that distinguish this novel species from V. cholerae. Comparative genomic analysis reveals a unique set of siderophore genes, indicating that iron acquisition strategies could be vital for the divergence of the novel species from a common ancestor with V. cholerae. On the basis of the genetic, phylogenetic and phenotypic differences observed, we propose that these isolates represent a novel species of the genus Vibrio, for which the name Vibrio tarriae sp. nov. is proposed. Strain 2521-89 (T) (= DSM 112461=CCUG 75318), isolated from lake water, is the type strain. |
Spatial analysis of genetic clusters and epidemiologic factors related to wild poliovirus type 1 persistence in Afghanistan and Pakistan.
Mendesid A , Whiteman A , Bullard K , Sharif S , Khurshidid A , Alam MM , Salman M , Fordid V , Blairid T , Burns CC , Ehrhardt D , Jorba J , Hsuid CH . PLoS Glob Public Health 2022 2 (6) e0000251 Following the certification of the World Health Organization Region of Africa as free of serotype 1 wild poliovirus (WPV1) in 2020, Afghanistan and Pakistan represent the last remaining WPV1 reservoirs. As efforts continue in these countries to progress to eradication, there is an opportunity for a deeper understanding of the spatiotemporal characteristics and epidemiological risk factors associated with continual WPV1 circulation in the region. Using poliovirus surveillance data from 2017-2019, we used pairwise comparisons of VP1 nucleotide sequences to illustrate the spatiotemporal WPV1 dispersal to identify key sources and destinations of potentially infected, highly mobile populations. We then predicted the odds of WPV1 detection at the district level using a generalized linear model with structural indicators of health, security, environment, and population demographics. We identified evidence of widespread population mobility based on WPV1 dispersal within and between the countries, and evidence indicating five districts in Afghanistan (Arghandab, Batikot, Bermel, Muhamandara and Nawzad) and four districts in Pakistan (Charsada, Dera Ismail Khan, Killa Abdullah and Khyber) act as cross-border WPV1 circulation reservoirs. We found that the probability of detecting WPV1 in a district increases with each armed conflict event (OR = 1.024, +- 0.008), level of food insecurity (OR = 1.531, +-0.179), and mean degrees Celsius during the months of greatest precipitation (OR = 1.079, +- 0.019). Our results highlight the multidisciplinary complexities contributing to the continued transmission of WPV1 in Afghanistan and Pakistan. We discuss the implications of our results, stressing the value of coordination during this final chapter of the wild polio virus eradication initiative. |
An Immunoinformatics Prediction of Novel Multi-Epitope Vaccines Candidate Against Surface Antigens of Nipah Virus.
Rahman MM , Puspo JA , Adib AA , Hossain ME , Alam MM , Sultana S , Islam A , Klena JD , Montgomery JM , Satter SM , Shirin T , Rahman MZ . Int J Pept Res Ther 2022 28 (4) 123 Nipah virus (NiV) is an emerging zoonotic virus causing outbreaks of encephalitis and respiratory illnesses in humans, with high mortality. NiV is considered endemic in Bangladesh and Southeast Asia. There are no licensed vaccines against NiV. This study aimed at predicting a dual-antigen multi-epitope subunit chimeric vaccine against surface-glycoproteins G and F of NiV. Targeted proteins were subjected to immunoinformatics analyses to predict antigenic B-cell and T-cell epitopes. The proposed vaccine designs were implemented based on the conservancy, population coverage, molecular docking, immune simulations, codon adaptation, secondary mRNA structure, and in-silico cloning. Total 40 T and B-cell epitopes were found to be conserved, antigenic (vaxijen-value > 0.4), non-toxic, non-allergenic, and human non-homologous. Of 12 hypothetical vaccines, two (NiV_BGD_V1 and NiV_BGD_V2) were strongly immunogenic, non-allergenic, and structurally stable. The proposed vaccine candidates show a negative Z-score (- 6.32 and - 6.67) and 83.6% and 89.3% of most rama-favored regions. The molecular docking confirmed the highest affinity of NiV_BGD_V1 and NiV_BGD_V2 with TLR-4 (ΔG = - 30.7) and TLR8 (ΔG = - 20.6), respectively. The vaccine constructs demonstrated increased levels of immunoglobulins and cytokines in humans and could be expressed properly using an adenoviral-based pAdTrack-CMV expression vector. However, more experimental investigations and clinical trials are needed to validate its efficacy and safety. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10989-022-10431-z. |
Estimating typhoid incidence from community-based serosurveys: a multicohort study
Aiemjoy K , Seidman JC , Saha S , Munira SJ , Islam Sajib MS , Sium SMA , Sarkar A , Alam N , Zahan FN , Kabir MS , Tamrakar D , Vaidya K , Shrestha R , Shakya J , Katuwal N , Shrestha S , Yousafzai MT , Iqbal J , Dehraj IF , Ladak Y , Maria N , Adnan M , Pervaiz S , Carter AS , Longley AT , Fraser C , Ryan ET , Nodoushani A , Fasano A , Leonard MM , Kenyon V , Bogoch II , Jeon HJ , Haselbeck A , Park SE , Zellweger RM , Marks F , Owusu-Dabo E , Adu-Sarkodie Y , Owusu M , Teunis P , Luby SP , Garrett DO , Qamar FN , Saha SK , Charles RC , Andrews JR . Lancet Microbe 2022 3 (8) e578-e587 BACKGROUND: The incidence of enteric fever, an invasive bacterial infection caused by typhoidal Salmonellae (Salmonella enterica serovars Typhi and Paratyphi), is largely unknown in regions without blood culture surveillance. The aim of this study was to evaluate whether new diagnostic serological markers for typhoidal Salmonella can reliably estimate population-level incidence. METHODS: We collected longitudinal blood samples from patients with blood culture-confirmed enteric fever enrolled from surveillance studies in Bangladesh, Nepal, Pakistan, and Ghana between 2016 and 2021 and conducted cross-sectional serosurveys in the catchment areas of each surveillance site. We used ELISAs to measure quantitative IgA and IgG antibody responses to hemolysin E and S Typhi lipopolysaccharide. We used Bayesian hierarchical models to fit two-phase power-function decay models to the longitudinal antibody responses among enteric fever cases and used the joint distributions of the peak antibody titres and decay rate to estimate population-level incidence rates from cross-sectional serosurveys. FINDINGS: The longitudinal antibody kinetics for all antigen-isotypes were similar across countries and did not vary by clinical severity. The seroincidence of typhoidal Salmonella infection among children younger than 5 years ranged between 58·5 per 100 person-years (95% CI 42·1-81·4) in Dhaka, Bangladesh, to 6·6 per 100 person-years (4·3-9·9) in Kavrepalanchok, Nepal, and followed the same rank order as clinical incidence estimates. INTERPRETATION: The approach described here has the potential to expand the geographical scope of typhoidal Salmonella surveillance and generate incidence estimates that are comparable across geographical regions and time. FUNDING: Bill & Melinda Gates Foundation. TRANSLATIONS: For the Nepali, Bengali and Urdu translations of the abstract see Supplementary Materials section. |
A memorandum of understanding has facilitated guideline development involving collaborating groups
Alam M , Getchius TS , Schünemann H , Amer YS , Bak A , Fatheree LA , Ginex P , Jakhmola P , Marsden GL , McFarlane E , Meremikwu M , Taske N , Temple-Smolkin RL , Ventura C , Burgers J , Bradfield L , O'Brien MD , Einhaus K , Kopp IB , Munn Z , Scudeller L , Schaefer C , Ibrahim SA , Kang BY , Ogunremi T , Morgan RL . J Clin Epidemiol 2021 144 8-15 OBJECTIVE: Collaboration between groups can facilitate the development of high-quality guidelines. While collaboration is often desirable, misunderstandings can occur. One method to minimize misunderstandings is the pre-specification of terms of engagement in a memorandum of understanding (MOU). This study considered when an MOU may be most helpful, and which key elements should be included. STUDY DESIGN AND SETTING: An international panel of representatives from guideline groups was convened. A literature review to identify publications and other documents relevant to the establishment of MOUs between two or more guideline groups, supplemented by available source documents, was used to inform development of a draft MOU resource. This was iteratively refined until consensus was achieved. RESULTS: The level of detail in an MOU may vary based on institutional preferences and the particular collaboration. Elements within an MOU include those pertaining to: (1) scope and purpose; (2) leadership and team; (3) methods and commitment; (4) review and endorsement; and (5) publication and dissemination. CONCLUSION: Since groups may have different expectations regarding how a collaboration will unfold, an MOU may mitigate preventable misunderstandings. The result may be a higher likelihood of producing a guideline without disruption and delay. |
Preliminary report of the insecticide susceptibility status of Aedes albopictus in Bangladesh
Al-Amin HM , Irish S , Lenhart A , Alam MS . Am J Trop Med Hyg 2021 106 (1) 332-333 Aedes albopictus is a highly invasive mosquito species and a vector of human arboviral diseases including dengue, chikungunya, and Zika. There are no effective drugs or vaccines for the treatment or prevention of most of these diseases, so the primary option for disease prevention and control is to target mosquitoes, often using insecticides. Despite vector control efforts, cases of arboviral diseases are increasing in Bangladesh and it is important to understand if this escalation is associated with the presence of insecticide resistance in Aedes populations, including Ae. albopictus. The CDC bottle bioassays performed on Ae. albopictus from two districts in Bangladesh detected resistance to permethrin but susceptibility to deltamethrin, malathion, and bendiocarb. The detection of permethrin resistance is worrisome, since arbovirus vector control strategies in Bangladesh currently include the use of permethrin. Routine monitoring of the susceptibility status of key vector populations in Bangladesh will allow a better understanding of resistance trends, enabling the strengthening of control strategies. |
Postmortem investigations and identification of multiple causes of child deaths: An analysis of findings from the Child Health and Mortality Prevention Surveillance (CHAMPS) network
Breiman RF , Blau DM , Mutevedzi P , Akelo V , Mandomando I , Ogbuanu IU , Sow SO , Madrid L , El Arifeen S , Garel M , Thwala NB , Onyango D , Sitoe A , Bassey IA , Keita AM , Alemu A , Alam M , Mahtab S , Gethi D , Varo R , Ojulong J , Samura S , Mehta A , Ibrahim AM , Rahman A , Vitorino P , Baillie VL , Agaya J , Tapia MD , Assefa N , Chowdhury AI , Scott JAG , Gurley ES , Kotloff KL , Jambai A , Bassat Q , Tippett-Barr BA , Madhi SA , Whitney CG . PLoS Med 2021 18 (9) e1003814 BACKGROUND: The current burden of >5 million deaths yearly is the focus of the Sustainable Development Goal (SDG) to end preventable deaths of newborns and children under 5 years old by 2030. To accelerate progression toward this goal, data are needed that accurately quantify the leading causes of death, so that interventions can target the common causes. By adding postmortem pathology and microbiology studies to other available data, the Child Health and Mortality Prevention Surveillance (CHAMPS) network provides comprehensive evaluations of conditions leading to death, in contrast to standard methods that rely on data from medical records and verbal autopsy and report only a single underlying condition. We analyzed CHAMPS data to characterize the value of considering multiple causes of death. METHODS AND FINDINGS: We examined deaths identified from December 2016 through November 2020 from 7 CHAMPS sites (in Bangladesh, Ethiopia, Kenya, Mali, Mozambique, Sierra Leone, and South Africa), including 741 neonatal, 278 infant, and 241 child <5 years deaths for which results from Determination of Cause of Death (DeCoDe) panels were complete. DeCoDe panelists included all conditions in the causal chain according to the ICD-10 guidelines and assessed if prevention or effective management of the condition would have prevented the death. We analyzed the distribution of all conditions listed as causal, including underlying, antecedent, and immediate causes of death. Among 1,232 deaths with an underlying condition determined, we found a range of 0 to 6 (mean 1.5, IQR 0 to 2) additional conditions in the causal chain leading to death. While pathology provides very helpful clues, we cannot always be certain that conditions identified led to death or occurred in an agonal stage of death. For neonates, preterm birth complications (most commonly respiratory distress syndrome) were the most common underlying condition (n = 282, 38%); among those with preterm birth complications, 256 (91%) had additional conditions in causal chains, including 184 (65%) with a different preterm birth complication, 128 (45%) with neonatal sepsis, 69 (24%) with lower respiratory infection (LRI), 60 (21%) with meningitis, and 25 (9%) with perinatal asphyxia/hypoxia. Of the 278 infant deaths, 212 (79%) had ≥1 additional cause of death (CoD) beyond the underlying cause. The 2 most common underlying conditions in infants were malnutrition and congenital birth defects; LRI and sepsis were the most common additional conditions in causal chains, each accounting for approximately half of deaths with either underlying condition. Of the 241 child deaths, 178 (75%) had ≥1 additional condition. Among 46 child deaths with malnutrition as the underlying condition, all had ≥1 other condition in the causal chain, most commonly sepsis, followed by LRI, malaria, and diarrheal disease. Including all positions in the causal chain for neonatal deaths resulted in 19-fold and 11-fold increases in attributable roles for meningitis and LRI, respectively. For infant deaths, the proportion caused by meningitis and sepsis increased by 16-fold and 11-fold, respectively; for child deaths, sepsis and LRI are increased 12-fold and 10-fold, respectively. While comprehensive CoD determinations were done for a substantial number of deaths, there is potential for bias regarding which deaths in surveillance areas underwent minimally invasive tissue sampling (MITS), potentially reducing representativeness of findings. CONCLUSIONS: Including conditions that appear anywhere in the causal chain, rather than considering underlying condition alone, markedly changed the proportion of deaths attributed to various diagnoses, especially LRI, sepsis, and meningitis. While CHAMPS methods cannot determine when 2 conditions cause death independently or may be synergistic, our findings suggest that considering the chain of events leading to death can better guide research and prevention priorities aimed at reducing child deaths. |
An international needs assessment survey of guideline developers demonstrates variability in resources and challenges to collaboration between organizations
Sultan S , Siedler MR , Morgan RL , Ogunremi T , Dahm P , Fatheree LA , Getchius TSD , Ginex PK , Jakhmola P , McFarlane E , Murad MH , Temple Smolkin RL , Amer YS , Alam M , Kang BY , Falck-Ytter Y , Mustafa RA . J Gen Intern Med 2021 37 (11) 2669-2677 BACKGROUND: The development of rigorous, high-quality clinical guidelines increases the need for resources and skilled personnel within guideline-producing organizations. While collaboration between organizations provides a unique opportunity to pool resources and save time and effort, the collaboration presents its own unique challenges. OBJECTIVE: To assess the perceived needs and current challenges of guideline producers worldwide related to guideline development and collaboration efforts. DESIGN: Survey questions were developed by the Guidelines International Network and the US GRADE Network, pilot-tested among attendees of a guideline development workshop, and disseminated electronically using convenience and snowball sampling methods. PARTICIPANTS: A total of 171 respondents representing 30 countries and more than 112 unique organizations were included in this analysis. MAIN MEASURES: The survey included free-response, multiple-choice, and seven-point Likert-scale questions. Questions assessed respondents' perceived value of guidelines, resource availability and needs, guideline development processes, and collaboration efforts of their organization. KEY RESULTS: Time required to develop high-quality systematic reviews and guidelines was the most relevant need (median=7; IQR=5.5-7). In-house resources to conduct literature searches (median=4; IQR=3-6) and the resources to develop rigorous guidelines rapidly (median=4; IQR=2-5) were perceived as the least available resources. Difficulties reconciling differences in guideline methodology (median=6; IQR=4-7) and the time required to establish collaborative agreements (median=6; IQR=5-6) were the most relevant barriers to collaboration between organizations. Results also indicated a general need for improvement in conflict of interest (COI) disclosure policies. CONCLUSION: The survey identified organizational challenges in supporting rigorous guideline development, including the time, resources, and personnel required. Connecting guideline developers to existing databases of high-quality systematic reviews and the use of freely available online platforms may facilitate guideline development. Guideline-producing organizations may also consider allocating resources to hiring or training personnel with expertise in systematic review methodologies or utilizing resources more effectively by establishing collaborations with other organizations. |
Deaths attributed to respiratory syncytial virus in young children in high-mortality rate settings: Report from Child Health and Mortality Prevention Surveillance (CHAMPS)
Blau DM , Baillie VL , Els T , Mahtab S , Mutevedzi P , Keita AM , Kotloff KL , Mehta A , Sow SO , Tapia MD , Tippett Barr BA , Oluoch BO , Onyango C , Revathi G , Verani JR , Abayneh M , Assefa N , Madrid L , Oundo JO , Scott JAG , Bassat Q , Mandomando I , Sitoe A , Valente M , Varo R , Bassey IA , Cain CJ , Jambai A , Ogbuanu I , Ojulong J , Alam M , El Arifeen S , Gurley ES , Rahman A , Rahman M , Waller JL , Dewey B , Breiman RF , Whitney CG , Madhi SA . Clin Infect Dis 2021 73 S218-s228 BACKGROUND: Lower respiratory tract infections are a leading cause of death in young children, but few studies have collected the specimens needed to define the role of specific causes. The Child Health and Mortality Prevention Surveillance (CHAMPS) platform aims to investigate causes of death in children aged <5 years in high-mortality rate settings, using postmortem minimally invasive tissue sampling and other advanced diagnostic techniques. We examined findings for deaths identified in CHAMPS sites in 7 countries in sub-Saharan Africa and south Asia to evaluate the role of respiratory syncytial virus (RSV). METHODS: We included deaths that occurred between December 2016 and December 2019. Panels determined causes of deaths by reviewing all available data including pathological results from minimally invasive tissue sampling, polymerase chain reaction screening for multiple infectious pathogens in lung tissue, nasopharyngeal swab, blood, and cerebrospinal fluid samples, clinical information from medical records, and verbal autopsies. RESULTS: We evaluated 1213 deaths, including 695 in neonates (aged <28 days), 283 in infants (28 days to <12 months), and 235 in children (12-59 months). RSV was detected in postmortem specimens in 67 of 1213 deaths (5.5%); in 24 deaths (2.0% of total), RSV was determined to be a cause of death, and it contributed to 5 other deaths. Younger infants (28 days to <6 months of age) accounted for half of all deaths attributed to RSV; 6.5% of all deaths in younger infants were attributed to RSV. RSV was the underlying and only cause in 4 deaths; the remainder (n = 20) had a median of 2 (range, 1-5) other conditions in the causal chain. Birth defects (n = 8) and infections with other pathogens (n = 17) were common comorbid conditions. CONCLUSIONS: RSV is an important cause of child deaths, particularly in young infants. These findings add to the substantial body of literature calling for better treatment and prevention options for RSV in high-mortality rate settings. |
Coding-Complete Sequence of a SARS-CoV-2 B.1.1.25 Lineage Obtained from an 8-Day-Old Deceased Neonate.
Alam M , Jahan MI , Jahan S , Blau DM , Rahman A , Rahman MZ , Hossain MZ , Gurley ES , Arifeen SE , Rahman M . Microbiol Resour Announc 2021 10 (35) e0075621 We report the complete genome sequence of a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) strain, hCoV-19/Bangladesh/icddrb-CHAMPS-BDAA02205/2021, obtained from a nasopharyngeal swab from a deceased neonate from Faridpur, Bangladesh. The strain belongs to lineage B.1.1.25 but contains some notable mutations similar to the B.1.1.7 lineage. |
Population analysis of Vibrio cholerae in aquatic reservoirs reveals a novel sister species (Vibrio paracholerae sp. nov.) with a history of association with humans.
Islam MT , Nasreen T , Kirchberger P , Liang KYH , Orata FD , Johura FT , Hussain NAS , Im MS , Tarr CL , Alam M , Boucher YF . Appl Environ Microbiol 2021 87 (17) Aem0042221 Most efforts to understand the biology of Vibrio cholerae have focused on a single group, the pandemic-generating lineage harbouring the strains responsible for all known cholera pandemics. Consequently, little is known about the diversity of this species in its native aquatic environment. To understand the differences in the V. cholerae populations inhabiting regions with a history of cholera cases and those lacking such a history, a comparative analysis of population composition was performed. Little overlap was found in lineage compositions between those in Dhaka (cholera endemic) located in the Ganges delta, and of Falmouth (no known history of cholera), a small coastal town on the United States east coast. The most striking difference was the presence of a group of related lineages at high abundance in Dhaka which was completely absent from Falmouth. Phylogenomic analysis revealed that these lineages form a cluster at the base of the phylogeny for the V. cholerae species, sufficiently differentiated genetically and phenotypically to form a novel species. A retrospective search revealed that strains from this species have been anecdotally found from around the world and were isolated as early as 1916 from a British soldier in Egypt suffering from choleraic diarrhoea. In 1935 Gardner and Venkatraman unofficially referred to a member of this group as Vibrio paracholerae. In recognition of this earlier designation, we propose the name Vibrio paracholerae sp. nov. for this bacterium. Genomic analysis suggests a link with human populations for this novel species and substantial interaction with its better-known sister species. Importance Cholera continues to remain a major public health threat around the globe. Understanding the ecology, evolution, and environmental adaptation of the causative agent Vibrio cholerae and tracking the emergence of novel lineages with pathogenic potential are essential to combat the problem. In this study, we investigated the population dynamics of Vibrio cholerae in an inland locality which is known as endemic for cholera and compared with that of a cholera free coastal location. We found the consistent presence of the pandemic generating V. cholerae in cholera-endemic Dhaka and an exclusive presence of a lineage phylogenetically distinct from other V. cholerae. Our study suggests that this lineage represents a novel species having pathogenic potential and a human link to its environmental abundance. The possible association with human population, co-existence and interaction with toxigenic V. cholerae in the natural environment make this potential human pathogen an important subject for future studies. |
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