Last data update: May 06, 2024. (Total: 46732 publications since 2009)
Records 1-30 (of 49 Records) |
Query Trace: Mohammad Z[original query] |
---|
Profiling metal-induced genotoxic endpoints
Shoeb Mohammad , Zarus Gregory M , Abadin Henry E . J Environ Health 2023 86 (5) 30-35 Many toxic metals are involved in the initiation and progression of DNA damage that can result in the activation of DNA damage response machinery at double- and single-stranded DNA; this response can result in global and gene-specific DNA alteration. The toxicological profiles from the Agency for Toxic Substances and Disease Registry (ATSDR) and several other studies have demonstrated the influence of metal exposure-induced genotoxic endpoints and epigenetic modifications. Our review systematically summarizes accumulating evidence from ATSDR toxicological profiles and the available literature that demonstrate a possible induction of various genotoxic endpoints and metal exposures. We include in this article studies on chromium, arsenic, nickel, lead, mercury, and zinc. |
Seroprevalence of SARS-CoV-2 Antibodies in Seattle, Washington—October 2019–April 2020 (preprint)
McCulloch DJ , Jackson ML , Hughes JP , Lester S , Mills L , Freeman B , Rasheed MAU , Thornburg NJ , Chu HY . medRxiv 2020 2020.12.07.20244103 Estimating prevalence of SARS-CoV-2 antibodies is important to determine disease burden. We tested residual samples from 763 Seattle-area adults for SARS-CoV-2 antibodies. Prevalence rose from 0% to 1.2% between October 2019–April 2020, suggesting a small percentage of this metropolitan-area cohort had been infected with SARS-CoV-2 at that time.Competing Interest StatementHelen Y. Chu receives research support from Cepheid and is a consultant for Merck, Pfizer, the Bill and Melinda Gates Foundation, and Ellume. Michael L. Jackson receives research funding from Sanofi Pasteur. Denise J. McCulloch, James P. Hughes, Sandra Lester, Lisa Mills, Brandi Freeman, Mohammad Ata Ut Rasheed, and Natalie J. Thornburg, declare no competing interests.Funding StatementThis work was supported by the University of Washington Department of Medicine Scholars Award to Helen Chu.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:University of Washington IRBAll necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived.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.YesThe data analyzed during the current study are available from the corresponding author on reasonable request. |
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. |
Seroprevalence of SARS-CoV-2 antibodies in Seattle, Washington: October 2019-April 2020.
McCulloch DJ , Jackson ML , Hughes JP , Lester S , Mills L , Freeman B , Rasheed MAU , Thornburg NJ , Chu HY . PLoS One 2021 16 (5) e0252235 BACKGROUND: The first US case of SARS-CoV-2 infection was detected on January 20, 2020. However, some serology studies suggest SARS-CoV-2 may have been present in the United States prior to that, as early as December 2019. The extent of domestic COVID-19 detection prior to 2020 has not been well-characterized. OBJECTIVES: To estimate the prevalence of SARS-CoV-2 antibody among healthcare users in the greater Seattle, Washington area from October 2019 through early April 2020. STUDY DESIGN: We tested residual samples from 766 Seattle-area adults for SARS-CoV-2 antibodies utilizing an ELISA against prefusion-stabilized Spike (S) protein. RESULTS: No antibody-positive samples were found between October 2, 2019 and March 13, 2020. Prevalence rose to 1.2% in late March and early April 2020. CONCLUSIONS: The absence of SARS-CoV-2 antibody-positive samples in October 2019 through mid-March, 2020, provides evidence against widespread circulation of COVID-19 among healthcare users in the Seattle area during that time. A small proportion of this metropolitan-area cohort had been infected with SARS-CoV-2 by spring of 2020. |
Laboratory Modeling of SARS-CoV-2 Exposure Reduction Through Physically Distanced Seating in Aircraft Cabins Using Bacteriophage Aerosol - November 2020.
Dietrich WL , Bennett JS , Jones BW , Hosni MH . MMWR Morb Mortal Wkly Rep 2021 70 (16) 595-599 Aircraft can hold large numbers of persons in close proximity for long periods, which can increase the risk for transmission of infectious disease.* Current CDC guidelines recommend against travel for persons who have not been vaccinated against COVID-19, and a January 2021 CDC order requires masking for all persons while on airplanes.(†)(,)(§) Research suggests that seating proximity on aircraft is associated with increased risk for infection with SARS-CoV-2, the virus that causes COVID-19 (1,2). However, studies quantifying the benefit of specific distancing strategies to prevent transmission, such as keeping aircraft cabin middle seats vacant, are limited. Using bacteriophage MS2 virus as a surrogate for airborne SARS-CoV-2, CDC and Kansas State University (KSU) modeled the relationship between SARS-CoV-2 exposure and aircraft seating proximity, including full occupancy and vacant middle seat occupancy scenarios. Compared with exposures in full occupancy scenarios, relative exposure in vacant middle seat scenarios was reduced by 23% to 57% depending upon the modeling approach. A 23% exposure reduction was observed for a single passenger who was in the same row and two seats away from the SARS-COV-2 source, rather than in an adjacent middle seat. When quantifying exposure reduction to a full 120-passenger cabin rather than to a single person, exposure reductions ranging from 35.0% to 39.4% were predicted. A 57% exposure reduction was observed under the vacant middle seat condition in a scenario involving a three-row section that contained a mix of SARS-CoV-2 sources and other passengers. Based on this laboratory model, a vacant middle seat reduces risk for exposure to SARS-CoV-2 from nearby passengers. These data suggest that increasing physical distance between passengers and lowering passenger density could help reduce potential COVID-19 exposures during air travel. Physical distancing of airplane passengers, including through policies such as middle seat vacancy, could provide additional reductions in SARS-CoV-2 exposure risk. |
Infectious Period of Severe Acute Respiratory Syndrome Coronavirus 2 in 17 Nursing Home Residents-Arkansas, June-August 2020.
Surie D , Huang JY , Brown AC , Gable P , Biedron C , Gilbert SE , Garner K , Bollinger S , Gulley T , Haney T , Lyons AK , Beshearse E , Gregory CJ , Sabour S , Clemmons NS , James AE , Tamin A , Reese N , Perry-Dow KA , Brown R , Harcourt JL , Campbell D , Houston H , Chakravorty R , Paulick A , Whitaker B , Murdoch J , Spicer L , Stumpf MM , Mills L , Coughlin MM , Higdem P , Rasheed MAU , Lonsway D , Bhatnagar A , Kothari A , Anderson K , Thornburg NJ , Breaker E , Adamczyk M , McAllister GA , Halpin AL , Seely KA , Patil N , McDonald LC , Kutty PK . Open Forum Infect Dis 2021 8 (3) ofab048 BACKGROUND: To estimate the infectious period of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in older adults with underlying conditions, we assessed duration of coronavirus disease 2019 (COVID-19) symptoms, reverse-transcription polymerase chain reaction (RT-PCR) positivity, and culture positivity among nursing home residents. METHODS: We enrolled residents within 15 days of their first positive SARS-CoV-2 test (diagnosis) at an Arkansas facility from July 7 to 15, 2020 and instead them for 42 days. Every 3 days for 21 days and then weekly, we assessed COVID-19 symptoms, collected specimens (oropharyngeal, anterior nares, and saliva), and reviewed medical charts. Blood for serology was collected on days 0, 6, 12, 21, and 42. Infectivity was defined by positive culture. Duration of culture positivity was compared with duration of COVID-19 symptoms and RT-PCR positivity. Data were summarized using measures of central tendency, frequencies, and proportions. RESULTS: We enrolled 17 of 39 (44%) eligible residents. Median participant age was 82 years (range, 58-97 years). All had ≥3 underlying conditions. Median duration of RT-PCR positivity was 22 days (interquartile range [IQR], 8-31 days) from diagnosis; median duration of symptoms was 42 days (IQR, 28-49 days). Of 9 (53%) participants with any culture-positive specimens, 1 (11%) severely immunocompromised participant remained culture-positive 19 days from diagnosis; 8 of 9 (89%) were culture-positive ≤8 days from diagnosis. Seroconversion occurred in 12 of 12 (100%) surviving participants with ≥1 blood specimen; all participants were culture-negative before seroconversion. CONCLUSIONS: Duration of infectivity was considerably shorter than duration of symptoms and RT-PCR positivity. Severe immunocompromise may prolong SARS-CoV-2 infectivity. Seroconversion indicated noninfectivity in this cohort. |
Shedding of culturable virus, seroconversion, and 6-month follow-up antibody responses in the first 14 confirmed cases of COVID-19 in the United States.
Killerby ME , Ata Ur Rasheed M , Tamin A , Harcourt JL , Abedi GR , Lu X , Kujawski S , Shah MM , Kirking HL , Gold JAW , Salvatore PP , Coughlin MM , Whitaker B , Tate JE , Watson JT , Lindstrom S , Hall AJ , Fry AM , Gerber SI , Midgley CM , Thornburg NJ . J Infect Dis 2021 224 (5) 771-776 We aimed to characterize presence of culturable virus in clinical specimens during acute illness, and antibody kinetics up to six months post-onset, among 14 early US COVID-19 patients. We isolated viable SARS-CoV-2 from rRT-PCR-positive respiratory specimens collected during days 0-8 post-onset, but not after. All 13 patients with two or more serum specimens developed anti-spike antibodies; 12 developed detectable neutralizing antibodies. We did not isolate virus after detection of neutralizing antibodies. Eight participants provided serum at six months post-onset; all retained detectable anti-spike IgG, and half had detectable neutralizing antibodies. Two participants reported not feeling fully recovered at six months. |
Behaviour adoption approaches during public health emergencies: implications for the COVID-19 pandemic and beyond.
Jalloh MF , Nur AA , Nur SA , Winters M , Bedson J , Pedi D , Prybylski D , Namageyo-Funa A , Hageman KM , Baker BJ , Jalloh MB , Eng E , Nordenstedt H , Hakim AJ . BMJ Glob Health 2021 6 (1) Human behaviour will continue to play an important role as the world grapples with public health threats. In this paper, we draw from the emerging evidence on behaviour adoption during diverse public health emergencies to develop a framework that contextualises behaviour adoption vis-à-vis a combination of top-down, intermediary and bottom-up approaches. Using the COVID-19 pandemic as a case study, we operationalise the contextual framework to demonstrate how these three approaches differ in terms of their implementation, underlying drivers of action, enforcement, reach and uptake. We illustrate how blended strategies that include all three approaches can help accelerate and sustain protective behaviours that will remain important even when safe and effective vaccines become more widely available. As the world grapples with the COVID-19 pandemic and prepares to respond to (re)emerging public health threats, our contextual framework can inform the design, implementation, tracking and evaluation of comprehensive public health and social measures during health emergencies. |
Detection of norovirus variant GII.4 Hong Kong in Asia and Europe, 2017-2019
Chan MC , Roy S , Bonifacio J , Zhang LY , Chhabra P , Chan JCM , Celma C , Igoy MA , Lau SL , Mohammad KN , Vinjé J , Vennema H , Breuer J , Koopmans M , de Graaf M . Emerg Infect Dis 2021 27 (1) 289-293 We report a new norovirus GII.4 variant, GII.4 Hong Kong, with low-level circulation in 4 Eurasia countries since mid-2017. Amino acid substitutions in key residues on the virus capsid associated with the emergence of pandemic noroviruses suggest that GII.4 Hong Kong has the potential to become the next pandemic variant. |
Insecticide resistance status of Aedes aegypti in Bangladesh.
Al-Amin HM , Johora FT , Irish SR , Hossainey MRH , Vizcaino L , Paul KK , Khan WA , Haque R , Alam MS , Lenhart A . Parasit Vectors 2020 13 (1) 622 BACKGROUND: Arboviral diseases, including dengue and chikungunya, are major public health concerns in Bangladesh where there have been unprecedented levels of transmission reported in recent years. The primary approach to control these diseases is to control the vector Aedes aegypti using pyrethroid insecticides. Although chemical control has long been practiced, no comprehensive analysis of Ae. aegypti susceptibility to insecticides has been conducted to date. The aim of this study was 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: Eggs of Aedes mosquitoes were collected using ovitraps from five districts across Bangladesh 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- to 5-day-old F(0)-F(2) 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 to 14.8% at the diagnostic dose. Substantial resistance continued to be detected against higher (2×) 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 (knockdown resistance) alleles varied across the Dhaka Aedes populations. Leu410 was not detected in any of the tested populations. CONCLUSIONS: The detection of widespread pyrethroid resistance and multiple resistance 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. |
Hospital-based Surveillance for Pediatric Norovirus Gastroenteritis in Bangladesh, 2012-2016.
Satter SM , Abdullah Z , Cardemil CV , Flora MS , Gurley ES , Rahman M , Talha M , Islam MD , Hossain ME , Balachandran N , Lopman B , Rahman M , Vinjé J , Hall AJ , Parashar UD . Pediatr Infect Dis J 2020 40 (3) 215-219 BACKGROUND: Globally, noroviruses are recognized as an important cause of acute gastroenteritis (AGE), but data from low and middle-income countries are limited. AIMS: To examine the epidemiology and strain diversity of norovirus infections among children hospitalized for AGE in Bangladesh. METHODS: We implemented active surveillance of children <5 years of age hospitalized with AGE at 8 geographically dispersed tertiary care hospitals in Bangladesh from July 2012 to June 2016. We tested random samples of AGE cases stratified by site and age group for norovirus by real-time RT-PCR. Noro-positive specimens were genotyped. Coinfection with rotavirus was assessed based on prior EIA testing. RESULTS: We enrolled 5622 total AGE cases, of which 1008 were tested for norovirus. Total of 137 (14%) AGE cases tested positive for norovirus (range, 11%-17% by site). Most (94%) norovirus-associated hospitalizations were among children less than 2 years of age. Norovirus was detected year-round, with higher detection from March to June (20%-38%) and November to January (9%-18%). Genogroup II (GII) noroviruses were detected in 96% of cases, and the most frequent genotypes were GII.4 Sydney [P4 New Orleans] (33%), GII.3 [P16] (20%), and GII.4 Sydney [P16] (11%). The proportion of norovirus-positive specimens was significantly greater among rotavirus-negative AGE patients compared with rotavirus-positive AGE patients (27% vs. 5%, P < 0.001). As measured by the Vesikari severity score, a similar proportion of norovirus and rotavirus positive AGE patients were considered severe (68% vs. 70%, P = 0.86). CONCLUSIONS: Norovirus is an important cause of AGE hospitalization in Bangladeshi children with most infections caused by GII viruses. |
Telomeres in toxicology: Occupational health.
Shoeb M , Meier HCS , Antonini JM . Pharmacol Ther 2020 220 107742 The ends of chromosomes shorten at each round of cell division, and this process is thought to be affected by occupational exposures. Occupational hazards may alter telomere length homeostasis resulting in DNA damage, chromosome aberration, mutations, epigenetic alterations and inflammation. Therefore, for the protection of genetic material, nature has provided a unique nucleoprotein structure known as a telomere. Telomeres provide protection by averting an inappropriate activation of the DNA damage response (DDR) at chromosomal ends and preventing recognition of single and double strand DNA (ssDNA and dsDNA) breaks or chromosomal end-to-end fusion. Telomeres and their interacting six shelterin complex proteins in coordination act as inhibitors of DNA damage machinery by blocking DDR activation at chromosomes, thereby preventing the occurrence of genome instability, perturbed cell cycle, cellular senescence and apoptosis. However, inappropriate DNA repair may result in the inadequate distribution of genetic material during cell division, resulting in the eventual development of tumorigenesis and other pathologies. This article reviews the current literature on the association of changes in telomere length and its interacting proteins with different occupational exposures and the potential application of telomere length or changes in the regulatory proteins as potential biomarkers for exposure and health response, including recent findings and future perspectives. |
The epidemiology and estimated etiology of pathogens detected from the upper respiratory tract of adults with severe acute respiratory infections in multiple countries, 2014-2015.
Milucky J , Pondo T , Gregory CJ , Iuliano D , Chaves SS , McCracken J , Mansour A , Zhang Y , Aleem MA , Wolff B , Whitaker B , Whistler T , Onyango C , Lopez MR , Liu N , Rahman MZ , Shang N , Winchell J , Chittaganpitch M , Fields B , Maldonado H , Xie Z , Lindstrom S , Sturm-Ramirez K , Montgomery J , Wu KH , Van Beneden CA . PLoS One 2020 15 (10) e0240309 INTRODUCTION: Etiology studies of severe acute respiratory infections (SARI) in adults are limited. We studied potential etiologies of SARI among adults in six countries using multi-pathogen diagnostics. METHODS: We enrolled both adults with SARI (acute respiratory illness onset with fever and cough requiring hospitalization) and asymptomatic adults (adults hospitalized with non-infectious illnesses, non-household members accompanying SARI patients, adults enrolled from outpatient departments, and community members) in each country. Demographics, clinical data, and nasopharyngeal and oropharyngeal specimens were collected from both SARI patients and asymptomatic adults. Specimens were tested for presence of 29 pathogens utilizing the Taqman® Array Card platform. We applied a non-parametric Bayesian regression extension of a partially latent class model approach to estimate proportions of SARI caused by specific pathogens. RESULTS: We enrolled 2,388 SARI patients and 1,135 asymptomatic adults from October 2013 through October 2015. We detected ≥1 pathogen in 76% of SARI patients and 67% of asymptomatic adults. Haemophilus influenzae and Streptococcus pneumoniae were most commonly detected (≥23% of SARI patients and asymptomatic adults). Through modeling, etiology was attributed to a pathogen in most SARI patients (range among countries: 57.3-93.2%); pathogens commonly attributed to SARI etiology included influenza A (14.4-54.4%), influenza B (1.9-19.1%), rhino/enterovirus (1.8-42.6%), and RSV (3.6-14.6%). CONCLUSIONS: Use of multi-pathogen diagnostics and modeling enabled attribution of etiology in most adult SARI patients, despite frequent detection of multiple pathogens in the upper respiratory tract. Seasonal flu vaccination and development of RSV vaccine would likely reduce the burden of SARI in these populations. |
Severe Acute Respiratory Syndrome Coronavirus 2 Prevalence, Seroprevalence, and Exposure among Evacuees from Wuhan, China, 2020.
Hallowell BD , Carlson CM , Jacobs JR , Pomeroy M , Steinberg J , Tenforde MW , McDonald E , Foster L , Feldstein LR , Rolfes MA , Haynes A , Abedi GR , Odongo GS , Saruwatari K , Rider EC , Douville G , Bhakta N , Maniatis P , Lindstrom S , Thornburg NJ , Lu X , Whitaker BL , Kamili S , Sakthivel SK , Wang L , Malapati L , Murray JR , Lynch B , Cetron M , Brown C , Roohi S , Rotz L , Borntrager D , Ishii K , Moser K , Rasheed M , Freeman B , Lester S , Corbett KS , Abiona OM , Hutchinson GB , Graham BS , Pesik N , Mahon B , Braden C , Behravesh CB , Stewart R , Knight N , Hall AJ , Killerby ME . Emerg Infect Dis 2020 26 (9) 1998-2004 To determine prevalence of, seroprevalence of, and potential exposure to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among a cohort of evacuees returning to the United States from Wuhan, China, in January 2020, we conducted a cross-sectional study of quarantined evacuees from 1 repatriation flight. Overall, 193 of 195 evacuees completed exposure surveys and submitted upper respiratory or serum specimens or both at arrival in the United States. Nearly all evacuees had taken preventive measures to limit potential exposure while in Wuhan, and none had detectable SARS-CoV-2 in upper respiratory tract specimens, suggesting the absence of asymptomatic respiratory shedding among this group at the time of testing. Evidence of antibodies to SARS-CoV-2 was detected in 1 evacuee, who reported experiencing no symptoms or high-risk exposures in the previous 2 months. These findings demonstrated that this group of evacuees posed a low risk of introducing SARS-CoV-2 to the United States. |
Seroprevalence of Antibodies to SARS-CoV-2 in 10 Sites in the United States, March 23-May 12, 2020.
Havers FP , Reed C , Lim T , Montgomery JM , Klena JD , Hall AJ , Fry AM , Cannon DL , Chiang CF , Gibbons A , Krapiunaya I , Morales-Betoulle M , Roguski K , Rasheed MAU , Freeman B , Lester S , Mills L , Carroll DS , Owen SM , Johnson JA , Semenova V , Blackmore C , Blog D , Chai SJ , Dunn A , Hand J , Jain S , Lindquist S , Lynfield R , Pritchard S , Sokol T , Sosa L , Turabelidze G , Watkins SM , Wiesman J , Williams RW , Yendell S , Schiffer J , Thornburg NJ . JAMA Intern Med 2020 IMPORTANCE: Reported cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection likely underestimate the prevalence of infection in affected communities. Large-scale seroprevalence studies provide better estimates of the proportion of the population previously infected. OBJECTIVE: To estimate prevalence of SARS-CoV-2 antibodies in convenience samples from several geographic sites in the US. DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study performed serologic testing on a convenience sample of residual sera obtained from persons of all ages. The serum was collected from March 23 through May 12, 2020, for routine clinical testing by 2 commercial laboratory companies. Sites of collection were San Francisco Bay area, California; Connecticut; south Florida; Louisiana; Minneapolis-St Paul-St Cloud metro area, Minnesota; Missouri; New York City metro area, New York; Philadelphia metro area, Pennsylvania; Utah; and western Washington State. EXPOSURES: Infection with SARS-CoV-2. MAIN OUTCOMES AND MEASURES: The presence of antibodies to SARS-CoV-2 spike protein was estimated using an enzyme-linked immunosorbent assay, and estimates were standardized to the site populations by age and sex. Estimates were adjusted for test performance characteristics (96.0% sensitivity and 99.3% specificity). The number of infections in each site was estimated by extrapolating seroprevalence to site populations; estimated infections were compared with the number of reported coronavirus disease 2019 (COVID-19) cases as of last specimen collection date. RESULTS: Serum samples were tested from 16 025 persons, 8853 (55.2%) of whom were women; 1205 (7.5%) were 18 years or younger and 5845 (36.2%) were 65 years or older. Most specimens from each site had no evidence of antibodies to SARS-CoV-2. Adjusted estimates of the proportion of persons seroreactive to the SARS-CoV-2 spike protein antibodies ranged from 1.0% in the San Francisco Bay area (collected April 23-27) to 6.9% of persons in New York City (collected March 23-April 1). The estimated number of infections ranged from 6 to 24 times the number of reported cases; for 7 sites (Connecticut, Florida, Louisiana, Missouri, New York City metro area, Utah, and western Washington State), an estimated greater than 10 times more SARS-CoV-2 infections occurred than the number of reported cases. CONCLUSIONS AND RELEVANCE: During March to early May 2020, most persons in 10 diverse geographic sites in the US had not been infected with SARS-CoV-2 virus. The estimated number of infections, however, was much greater than the number of reported cases in all sites. The findings may reflect the number of persons who had mild or no illness or who did not seek medical care or undergo testing but who still may have contributed to ongoing virus transmission in the population. |
A Vibrio cholerae Core Genome Multilocus Sequence Typing Scheme to Facilitate the Epidemiological Study of Cholera.
Liang KYH , Orata FD , Islam MT , Nasreen T , Alam M , Tarr CL , Boucher YF . J Bacteriol 2020 202 (24) 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/).IMPORTANCEToxigenic Vibrio cholerae of the O1 and O139 serogroups are the causative agents of cholera, an acute diarrheal disease that plagued the world for centuries, if not millennia. Here, we introduce a core genome multilocus sequence typing scheme for V. cholerae Using this scheme, we have standardized the definition for subspecies-level classification, facilitating global collaboration in the surveillance of V. cholerae In addition, this typing scheme allows for quick identification of outbreak-related isolates that can guide subsequent analyses, serving as an important first step in epidemiological research. This scheme is also easily scalable to analyze thousands of isolates at various levels of resolution making it an invaluable tool for large-scale ecological and evolutionary analyses. |
Validation of a SARS-CoV-2 spike protein ELISA for use in contact investigations and serosurveillance.
Freeman B , Lester S , Mills L , Rasheed MAU , Moye S , Abiona O , Hutchinson GB , Morales-Betoulle M , Krapinunaya I , Gibbons A , Chiang CF , Cannon D , Klena J , Johnson JA , Owen SM , Graham BS , Corbett KS , Thornburg NJ . bioRxiv 2020 Since emergence of SARS-CoV-2 in late 2019, there has been a critical need to understand prevalence, transmission patterns, to calculate the burden of disease and case fatality rates. Molecular diagnostics, the gold standard for identifying viremic cases, are not ideal for determining true case counts and rates of asymptomatic infection. Serological detection of SARS-CoV-2 specific antibodies can contribute to filling these knowledge gaps. In this study, we describe optimization and validation of a SARS-CoV-2-specific-enzyme linked immunosorbent assay (ELISA) using the prefusion-stabilized form of the spike protein [1]. We performed receiver operator characteristic (ROC) analyses to define the specificities and sensitivities of the optimized assay and examined cross reactivity with immune sera from persons confirmed tohave had infections with other coronaviruses. These assays will be used to perform contact investigations and to conduct large-scale, cross sectional surveillance to define disease burden in the population. |
Outbreak of diarrhoea in piglets caused by novel rotavirus genotype G4P[49] in north-western district of Bangladesh, February 2014.
Sarkar S , Dioh Esona M , Gautam R , Castro CJ , Ng TFF , Haque W , Khan SU , Hossain ME , Rahman MZ , Gurley ES , Kennedy ED , Bowen MD , Parashar UD , Rahman M . Transbound Emerg Dis 2019 67 (1) 442-449 Group A rotavirus (RVA) associated diarrhea in piglets represents one of the major causes of morbidity and mortality in pig farms worldwide. A diarrhea outbreak occurred among nomadic piglets in north-western district of Bangladesh in February 2014. Outbreak investigation was performed to identify the cause, epidemiologic and clinical features of the outbreak. Rectal swabs and clinical information were collected from diarrheic piglets (n=36). Rectal swabs were tested for RVA RNA by real time reverse transcription polymerase chain reaction (rRT-PCR) using NSP3-specific primers. The G (VP7) and P (VP4) genes were typed by conventional RT-PCR and sanger sequencing and full genome sequences were determined using next generation sequencing. We found the attack rate was 61% (50/82) among piglets in the nomadic pig herd and the case fatality rate was 20% (10/50) among piglets with diarrhea. All study piglets cases had watery diarrhea, lack of appetite or reluctance to move. A novel RVA strain with a new P[49] genotype combined with G4 was identified among all piglets with diarrhea. The genome constellation of the novel RVA strains was determined to be G4-P [49]-I1-R1-C1-M1-A8-N1-T7-E1-H1. Genetic analysis shows that the novel G4P[49] strain is similar to Indian and Chinese porcine or porcine-like G4 human strains and is genetically distant from Bangladeshi human G4 strains. Identification of this novel RVA strain warrants further exploration for disease severity and zoonotic potential. This article is protected by copyright. All rights reserved. |
One hypervirulent clone, sequence type 283, accounts for a large proportion of invasive Streptococcus agalactiae isolated from humans and diseased tilapia in Southeast Asia.
Barkham T , Zadoks RN , Azmai MNA , Baker S , Bich VTN , Chalker V , Chau ML , Dance D , Deepak RN , van Doorn HR , Gutierrez RA , Holmes MA , Huong LNP , Koh TH , Martins E , Mehershahi K , Newton P , Ng LC , Phuoc NN , Sangwichian O , Sawatwong P , Surin U , Tan TY , Tang WY , Thuy NV , Turner P , Vongsouvath M , Zhang D , Whistler T , Chen SL . PLoS Negl Trop Dis 2019 13 (6) e0007421 BACKGROUND: In 2015, Singapore had the first and only reported foodborne outbreak of invasive disease caused by the group B Streptococcus (GBS; Streptococcus agalactiae). Disease, predominantly septic arthritis and meningitis, was associated with sequence type (ST)283, acquired from eating raw farmed freshwater fish. Although GBS sepsis is well-described in neonates and older adults with co-morbidities, this outbreak affected non-pregnant and younger adults with fewer co-morbidities, suggesting greater virulence. Before 2015 ST283 had only been reported from twenty humans in Hong Kong and two in France, and from one fish in Thailand. We hypothesised that ST283 was causing region-wide infection in Southeast Asia. METHODOLOGY/PRINCIPAL FINDINGS: We performed a literature review, whole genome sequencing on 145 GBS isolates collected from six Southeast Asian countries, and phylogenetic analysis on 7,468 GBS sequences including 227 variants of ST283 from humans and animals. Although almost absent outside Asia, ST283 was found in all invasive Asian collections analysed, from 1995 to 2017. It accounted for 29/38 (76%) human isolates in Lao PDR, 102/139 (73%) in Thailand, 4/13 (31%) in Vietnam, and 167/739 (23%) in Singapore. ST283 and its variants were found in 62/62 (100%) tilapia from 14 outbreak sites in Malaysia and Vietnam, in seven fish species in Singapore markets, and a diseased frog in China. CONCLUSIONS: GBS ST283 is widespread in Southeast Asia, where it accounts for a large proportion of bacteraemic GBS, and causes disease and economic loss in aquaculture. If human ST283 is fishborne, as in the Singapore outbreak, then GBS sepsis in Thailand and Lao PDR is predominantly a foodborne disease. However, whether transmission is from aquaculture to humans, or vice versa, or involves an unidentified reservoir remains unknown. Creation of cross-border collaborations in human and animal health are needed to complete the epidemiological picture. |
Detection of highly pathogenic avian influenza A(H5N6) viruses in waterfowl in Bangladesh.
Yang G , Chowdury S , Hodges E , Rahman MZ , Jang Y , Hossain ME , Jones J , Stark TJ , Di H , Cook PW , Ghosh S , Azziz-Baumgartner E , Barnes JR , Wentworth DE , Kennedy E , Davis CT . Virology 2019 534 36-44 Bangladesh has reported repeated outbreaks of highly pathogenic avian influenza (HPAI) A(H5) viruses in poultry since 2007. Because of the large number of live poultry markets (LPM) relative to the population density of poultry throughout the country, these markets can serve as sentinel sites for HPAI A(H5) detection. Through active LPM surveillance during June 2016-June 2017, HPAI A(H5N6) viruses along with 14 other subtypes of influenza A viruses were detected. The HPAI A(H5N6) viruses belonged to clade 2.3.4.4 and were likely introduced into Bangladesh around March 2016. Human infections with influenza clade 2.3.4.4 viruses in Bangladesh have not been identified, but the viruses had several molecular markers associated with potential human infection. Vigilant surveillance at the animal-human interface is essential to identify emerging avian influenza viruses with the potential to threaten public and animal health. |
Effect of Age, High-Fat Diet, and Rat Strain on Serum Biomarkers and Telomere Length and Global DNA Methylation in Peripheral Blood Mononuclear Cells.
Antonini JM , Kodali V , Meighan TG , Roach KA , Roberts JR , Salmen R , Boyce GR , Zeidler-Erdely PC , Kashon M , Erdely A , Shoeb M . Sci Rep 2019 9 (1) 1996 The objective of the current study was to determine if age, diet, and genetic disposition (animal strain) in an animal model had early effects on specific molecular markers in circulating peripheral blood mononuclear cells (PBMCs). Three strains [Sprague-Dawley (SD), Fischer 344 (F344), and Brown-Norway (BN)] of male rats were maintained on a high-fat (HF) or regular diet. Blood was collected at 4, 12, and 24 wk to assess chemistry and to recover PBMCs. Triglycerides and body weight gain increased at all time points in the HF diet group for each strain. Telomere length in PBMCs decreased in the HF diet group compared to the regular diet group up to 24 wk in all strains. Telomere length decreased in PBMCs at 24 wk compared to baseline in all strains, indicating an age-related effect. These findings highlight that diet and age cause changes in PBMCs recovered from different strains of rats. The next tier of studies will examine the contribution of an occupational exposure (e.g., welding fume inhalation) in combination with diet, age, and strain, to assess changes in the molecular responses of isolated PBMCs. In addition, studies involving lifestyle exposure (e.g., tobacco smoke) are in the planning stages and will assess the long-term effects of exposure in our animal model. |
Initiation of Pulmonary Fibrosis after Silica Inhalation in Rats is linked with Dysfunctional Shelterin Complex and DNA Damage Response.
Shoeb M , Mustafa GM , Joseph P , Umbright C , Kodali V , Roach KA , Meighan T , Roberts JR , Erdely A , Antonini JM . Sci Rep 2019 9 (1) 471 Occupational exposure to silica has been observed to cause pulmonary fibrosis and lung cancer through complex mechanisms. Telomeres, the nucleoprotein structures with repetitive (TTAGGG) sequences at the end of chromosomes, are a molecular "clock of life", and alterations are associated with chronic disease. The shelterin complex (POT1, TRF1, TRF2, Tin2, Rap1, and POT1 and TPP1) plays an important role in maintaining telomere length and integrity, and any alteration in telomeres may activate DNA damage response (DDR) machinery resulting in telomere attrition. The goal of this study was to assess the effect of silica exposure on the regulation of the shelterin complex in an animal model. Male Fisher 344 rats were exposed by inhalation to Min-U-Sil 5 silica for 3, 6, or 12 wk at a concentration of 15 mg/m(3) for 6 hr/d for 5 consecutive d/wk. Expression of shelterin complex genes was assessed in the lungs at 16 hr after the end of each exposure. Also, the relationship between increased DNA damage protein (gammaH2AX) and expression of silica-induced fibrotic marker, alphaSMA, was evaluated. Our findings reveal new information about the dysregulation of shelterin complex after silica inhalation in rats, and how this pathway may lead to the initiation of silica-induced pulmonary fibrosis. |
Draft Genome Sequences of Eight Vibrio sp. Clinical Isolates from across the United States That Form a Basal Sister Clade to Vibrio cholerae.
Liang K , Islam MT , Hussain N , Winkjer NS , Im MS , Rowe LA , Tarr CL , Boucher Y . Microbiol Resour Announc 2019 8 (3) We sequenced the genomes of eight isolates from various regions of the United States. These isolates form a monophyletic cluster clearly related to but distinct from Vibrio cholerae. Phylogenetic and genomic analyses suggest that they represent a basal lineage highly divergent from Vibrio cholerae or a novel species. |
PCR-based method for S. flexneri serotyping: International Multicenter Validation.
Brengi SP , Sun Q , Bolanos H , Duarte F , Jenkins C , Pichel M , Shahnaij M , Sowers EG , Strockbine N , Talukder KA , Derado G , Vinas MR , Kam KM , Xu J . J Clin Microbiol 2019 57 (4) Shigella is a leading cause of human diarrheal disease worldwide with S. flexneri being the most frequently isolated in developing countries. This serogroup is presently classified into 19 serotypes worldwide. We report here a Multicenter Validation of a Multiplex PCR based-strategy previously developed by Sun et al. (doi: 10.1128/JCM.01259-11) for molecular serotyping of S. flexneri This study was performed by seven international laboratories, with a panel of 71 blinded strains as well as 279 strains collected from each own local culture collections. This collaborative work found high extent of agreement among laboratories, calculated through IRR measures for PCR test, proven its robustness. It was also observed agreement with traditional method (serology) in all laboratories for 14 serotypes studied, while specific genetic events could be responsible for the discrepancies among methodologies in other five serotypes as determined by PCR product sequencing in most of the cases. This work provided an empirical frame that allowed the use of this molecular method to serotype S. flexneri, and showed several advantages over the traditional method of serological typing. These included overcoming the problem of availability of suitable antisera in testing laboratories, as well as facilitated the analysis of multiple samples at the same time. The method is also less time consuming for completion, and easier to implement in routine laboratories. We recommend that this PCR be adopted, as it is a reliable diagnostic and characterization methodology that can be used globally for laboratory-based shigellae surveillance. |
The phylogeography and incidence of multi-drug resistant typhoid fever in sub-Saharan Africa.
Park SE , Pham DT , Boinett C , Wong VK , Pak GD , Panzner U , Espinoza LMC , von Kalckreuth V , Im J , Schutt-Gerowitt H , Crump JA , Breiman RF , Adu-Sarkodie Y , Owusu-Dabo E , Rakotozandrindrainy R , Soura AB , Aseffa A , Gasmelseed N , Keddy KH , May J , Sow AG , Aaby P , Biggs HM , Hertz JT , Montgomery JM , Cosmas L , Fields B , Sarpong N , Razafindrabe TJL , Raminosoa TM , Kabore LP , Sampo E , Teferi M , Yeshitela B , El Tayeb MA , Sooka A , Meyer CG , Krumkamp R , Dekker DM , Jaeger A , Poppert S , Tall A , Niang A , Bjerregaard-Andersen M , Valborg Løfberg S , Seo HJ , Jeon HJ , Deerin JF , Park J , Konings F , Ali M , Clemens JD , Hughes P , Sendagala JN , Vudriko T , Downing R , Ikumapayi UN , Mackenzie GA , Obaro S , Argimon S , Aanensen DM , Page A , Keane JA , Duchene S , Dyson Z , Holt KE , Dougan G , Marks F , Baker S . Nat Commun 2018 9 (1) 5094 There is paucity of data regarding the geographical distribution, incidence, and phylogenetics of multi-drug resistant (MDR) Salmonella Typhi in sub-Saharan Africa. Here we present a phylogenetic reconstruction of whole genome sequenced 249 contemporaneous S. Typhi isolated between 2008-2015 in 11 sub-Saharan African countries, in context of the 2,057 global S. Typhi genomic framework. Despite the broad genetic diversity, the majority of organisms (225/249; 90%) belong to only three genotypes, 4.3.1 (H58) (99/249; 40%), 3.1.1 (97/249; 39%), and 2.3.2 (29/249; 12%). Genotypes 4.3.1 and 3.1.1 are confined within East and West Africa, respectively. MDR phenotype is found in over 50% of organisms restricted within these dominant genotypes. High incidences of MDR S. Typhi are calculated in locations with a high burden of typhoid, specifically in children aged <15 years. Antimicrobial stewardship, MDR surveillance, and the introduction of typhoid conjugate vaccines will be critical for the control of MDR typhoid in Africa. |
Draft Genome Sequences of Nine Vibrio sp. Isolates from across the United States Closely Related to Vibrio cholerae.
Islam MT , Liang K , Im MS , Winkjer J , Busby S , Tarr CL , Boucher Y . Microbiol Resour Announc 2018 7 (21) We are reporting whole-genome sequences of nine Vibrio sp. isolates closely related to the waterborne human pathogen Vibrio cholerae. These isolates were recovered from sources, including human samples, from different regions of the United States. Genome analysis suggests that this group of isolates represents a highly divergent basal V. cholerae lineage or a closely related novel species. |
Trends in poliovirus seroprevalence in Kano State, Northern Nigeria
Verma H , Iliyasu Z , Craig KT , Molodecky NA , Urua U , Jibir BW , Gwarzo GD , Gajida AU , McDonald S , Weldon WC , Oberste MS , Braka F , Mkanda P , Sutter RW . Clin Infect Dis 2018 67 S103-s109 Background: Kano state has been a protracted reservoir of poliovirus in Nigeria. Immunity trends have been monitored through seroprevalence surveys since 2011. The survey in 2015 was, in addition, intended to assess the impact of use of inactivated poliovirus vaccine (IPV). Methods: It was a health facility based seroprevalence survey. Eligible children aged 6-9, 12-15 and 19-22 months of age brought to the paediatrics outpatient department of Murtala Mohammad Specialist Hospital between 19 October and 6 November 2015, were screened for eligibility. Eligible children were enrolled after parental consent, history taken, physical examination conducted, and a blood sample collected to test for neutralizing antibody titres against the three poliovirus serotypes. Results: Overall, 365 results were available in the three age groups. In the 6-9-month-old age group, the seroprevalence was 73% (95% confidence interval [CI] 64-80%), 83% (95% CI 75-88%), and 66% (95% CI 57-73%) for serotypes 1, 2, and 3, respectively. In the 12-15- and 19-22-month-old age groups, seroprevalence was higher but still remained <90% across serotypes. Seroprevalence to serotypes 1 and 3 in 2015 was similar to 2014; however, for serotype 2 there was a significant improvement. IPV received in supplemental immunization activities was found to be a significant predictor of seropositivity among 6-9-month-old infants for serotypes 1 and 2. Conclusions: Seroprevalence for serotypes 1 and 3 remains low (<80%) in 6-9-month-olds. This poses a significant risk for poliovirus spread if reintroduced into the population. Efforts to strengthen immunization coverage are imperative to secure and sustain high population immunity. |
Epidemiologic and Genotypic distribution of Noroviruses among children with Acute Diarrhea and Healthy Controls in a Low-income Rural Setting.
Hossain ME , Rahman R , Ali SI , Islam MM , Rahman MZ , Ahmed S , Faruque ASG , Barclay L , Vinje J , Rahman M . Clin Infect Dis 2018 69 (3) 505-513 Background: Noroviruses are the most common cause of epidemic and endemic acute gastroenteritis (AGE) worldwide. The burden of norovirus disease in low-income settings is poorly understood. Methods: We tested stool samples from children less than 5 years of age with diarrhea who were admitted in a rural hospital in Bangladesh from 2010-2012 and from matched healthy controls from the same catchment area. Results: Norovirus was detected in 109 (18%) of 613 children with diarrhea and in 30 (15%) of 206 healthy controls. Most (n=118; 85%) norovirus infections belonged to genogroup II (GII). Of these, GII.4 viruses were identified in 36 (33%) of the cases and in 6 (21%) of the controls. Other major genotypes included GII.3 (13%), GII.6 (11%), and GII.13 (11%) in cases and GII.6 (17%) and GII.2 (14%) in controls. Greatest risk of severe norovirus disease (Vesikari score >/=11) was associated to GII.4 infections. GII.4 viruses were the predominant genotype detected during the winter (55%) and rainy season (23%) while GII.3 (19%) and GII.13 (19%) viruses were the most prevalent genotypes during the summer. Vomiting was significantly associated with GII.4 infection, while longer duration of diarrhea with GI.3 infection. Conclusions: Future studies are needed to understand the high rates of virus shedding in children without AGE symptoms. |
Multihospital Outbreak of a Middle East Respiratory Syndrome Coronavirus Deletion Variant, Jordan: A Molecular, Serologic, and Epidemiologic Investigation.
Payne DC , Biggs HM , Al-Abdallat MM , Alqasrawi S , Lu X , Abedi GR , Haddadin A , Iblan I , Alsanouri T , Al Nsour M , Sheikh Ali S , Rha B , Trivedi SU , Rasheed MAU , Tamin A , Lamers MM , Haagmans BL , Erdman DD , Thornburg NJ , Gerber SI . Open Forum Infect Dis 2018 5 (5) ofy095 Background: An outbreak of Middle East respiratory syndrome coronavirus (MERS-CoV) in Jordan in 2015 involved a variant virus that acquired distinctive deletions in the accessory open reading frames. We conducted a molecular and seroepidemiologic investigation to describe the deletion variant's transmission patterns and epidemiology. Methods: We reviewed epidemiologic and medical chart data and analyzed viral genome sequences from respiratory specimens of MERS-CoV cases. In early 2016, sera and standardized interviews were obtained from MERS-CoV cases and their contacts. Sera were evaluated by nucleocapsid and spike protein enzyme immunoassays and microneutralization. Results: Among 16 cases, 11 (69%) had health care exposure and 5 (31%) were relatives of a known case; 13 (81%) were symptomatic, and 7 (44%) died. Genome sequencing of MERS-CoV from 13 cases revealed 3 transmissible deletions associated with clinical illness during the outbreak. Deletion variant sequences were epidemiologically clustered and linked to a common transmission chain. Interviews and sera were collected from 2 surviving cases, 23 household contacts, and 278 health care contacts; 1 (50%) case, 2 (9%) household contacts, and 3 (1%) health care contacts tested seropositive. Conclusions: The MERS-CoV deletion variants retained human-to-human transmissibility and caused clinical illness in infected persons despite accumulated mutations. Serology suggested limited transmission beyond that detected during the initial outbreak investigation. |
Molecular xenomonitoring for Wuchereria bancrofti in Culex quinquefasciatus in two districts in Bangladesh supports transmission assessment survey findings.
Irish SR , Al-Amin HM , Paulin HN , Mahmood Asms , Khan RK , Muraduzzaman AKM , Worrell CM , Flora MS , Karim MJ , Shirin T , Shamsuzzaman AKM , Tahmina S , Lenhart A , Dubray C . PLoS Negl Trop Dis 2018 12 (7) e0006574 BACKGROUND: Careful monitoring for recrudescence of Wuchereria bancrofti infection is necessary in communities where mass drug administration (MDA) for the elimination of lymphatic filariasis (LF) as a public health problem has been stopped. During the post-MDA period, transmission assessment surveys (TAS) are recommended by the World Health Organization to monitor the presence of the parasite in humans. Molecular xenomonitoring (MX), a method by which parasite infection in the mosquito population is monitored, has also been proposed as a sensitive method to determine whether the parasite is still present in the human population. The aim of this study was to conduct an MX evaluation in two areas of Bangladesh, one previously endemic district that had stopped MDA (Panchagarh), and part of a non-endemic district (Gaibandha) that borders the district where transmission was most recently recorded. METHODOLOGY/PRINCIPAL FINDINGS: Mosquitoes were systematically collected from 180 trap sites per district and mosquito pools were tested for W. bancrofti using real-time PCR. A total of 23,436 intact mosquitoes, representing 31 species, were collected from the two districts, of which 10,344 (41%) were Culex quinquefasciatus, the vector of W. bancrofti in Bangladesh. All of the 594 pools of Cx. quinquefasciatus tested by real-time PCR were negative for the presence of W. bancrofti DNA. CONCLUSIONS/SIGNIFICANCE: This study suggested the absence of W. bancrofti in these districts. MX could be a sensitive tool to confirm interruption of LF transmission in areas considered at higher risk of recrudescence, particularly in countries like Bangladesh where entomological and laboratory capacity to perform MX is available. |
- Page last reviewed:Feb 1, 2024
- Page last updated:May 06, 2024
- Content source:
- Powered by CDC PHGKB Infrastructure