Last data update: Apr 29, 2024. (Total: 46658 publications since 2009)
Records 1-23 (of 23 Records) |
Query Trace: Osman S [original query] |
---|
Prevention of zoonotic spillover: From relying on response to reducing the risk at source
Wanda M , Thomas CM , Wiku BA , Salama A , Casey BB , Pépé B , Salome AB , Natalia C , Natalia CB , Dominique FC , Abhishek C , Janice RCZ , Andrew AC , Osman D , Nitish D , Baptiste D , Elmoubasher F , George FG , David TSH , Margaret K , Marion PGK , Catherine M , John SM , Serge M , Vyacheslav S , Zhou L , Giraudoux P . PLoS Pathog 2023 19 (10) e1011504 |
Inclusion of deuterated glycopeptides provides increased sequence coverage in hydrogen/deuterium exchange mass spectrometry analysis of SARS-CoV-2 spike glycoprotein
Haynes CA , Keppel TR , Mekonnen B , Osman SH , Zhou Y , Woolfitt AR , Baudys J , Barr JR , Wang D . Rapid Commun Mass Spectrom 2024 38 (5) Rationale: Hydrogen/deuterium exchange mass spectrometry (HDX-MS) can provide precise analysis of a protein's conformational dynamics across varied states, such as heat-denatured versus native protein structures, localizing regions that are specifically affected by such conditional changes. Maximizing protein sequence coverage provides high confidence that regions of interest were located by HDX-MS, but one challenge for complete sequence coverage is N-glycosylation sites. The deuteration of peptides post-translationally modified by asparagine-bound glycans (glycopeptides) has not always been identified in previous reports of HDX-MS analyses, causing significant sequence coverage gaps in heavily glycosylated proteins and uncertainty in structural dynamics in many regions throughout a glycoprotein. Methods: We detected deuterated glycopeptides with a Tribrid Orbitrap Eclipse mass spectrometer performing data-dependent acquisition. An MS scan was used to identify precursor ions; if high-energy collision-induced dissociation MS/MS of the precursor indicated oxonium ions diagnostic for complex glycans, then electron transfer low-energy collision-induced dissociation MS/MS scans of the precursor identified the modified asparagine residue and the glycan's mass. As in traditional HDX-MS, the identified glycopeptides were then analyzed at the MS level in samples labeled with D2O. Results: We report HDX-MS analysis of the SARS-CoV-2 spike protein ectodomain in its trimeric prefusion form, which has 22 predicted N-glycosylation sites per monomer, with and without heat treatment. We identified glycopeptides and calculated their average isotopic mass shifts from deuteration. Inclusion of the deuterated glycopeptides increased sequence coverage of spike ectodomain from 76% to 84%, demonstrated that glycopeptides had been deuterated, and improved confidence in results localizing structural rearrangements. Conclusion: Inclusion of deuterated glycopeptides improves the analysis of the conformational dynamics of glycoproteins such as viral surface antigens and cellular receptors. Published 2024. This article is a U.S. Government work and is in the public domain in the USA. |
Structural basis of the American mink ACE2 binding by Y453F trimeric spike glycoproteins of SARS-CoV-2
Ahn H , Calderon BM , Fan X , Gao Y , Horgan NL , Jiang N , Blohm DS , Hossain J , Rayyan NWK , Osman SH , Lin X , Currier M , Steel J , Wentworth DE , Zhou B , Liang B . J Med Virol 2023 95 (10) e29163 Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) enters the host cell by binding to angiotensin-converting enzyme 2 (ACE2). While evolutionarily conserved, ACE2 receptors differ across various species and differential interactions with Spike (S) glycoproteins of SARS-CoV-2 viruses impact species specificity. Reverse zoonoses led to SARS-CoV-2 outbreaks on multiple American mink (Mustela vison) farms during the pandemic and gave rise to mink-associated S substitutions known for transmissibility between mink and zoonotic transmission to humans. In this study, we used bio-layer interferometry (BLI) to discern the differences in binding affinity between multiple human and mink-derived S glycoproteins of SARS-CoV-2 and their respective ACE2 receptors. Further, we conducted a structural analysis of a mink variant S glycoprotein and American mink ACE2 (mvACE2) using cryo-electron microscopy (cryo-EM), revealing four distinct conformations. We discovered a novel intermediary conformation where the mvACE2 receptor is bound to the receptor-binding domain (RBD) of the S glycoprotein in a "down" position, approximately 34° lower than previously reported "up" RBD. Finally, we compared residue interactions in the S-ACE2 complex interface of S glycoprotein conformations with varying RBD orientations. These findings provide valuable insights into the molecular mechanisms of SARS-CoV-2 entry. |
Monitoring workers' health: focus on rights, determinants, and equity
Pega F , Momen NC , Abubakar AHA , Al-Emam R , Hassan MN , Howard J , Hussein SH , Iavicoli S , Kevi SK , Kgalamono SM , Malik SMR , K GM , Osman AY , Pandav RS , Shrestha RRP , Singh DR , Sun X , Wotobe MK , Neira MP . Lancet 2023 402 (10410) 1306-1308 The Lancet Series on Work and Health1, 2, 3 recognises that changes in the world of work are causing new occupational hazards to physical and mental health and increasing health inequalities within and between countries. These changes have profound implications for official workers’ health data and monitoring systems, which have become a global health priority as the world seeks to reach the Sustainable Development Goals (SDGs).4, 5 These monitoring systems are public goods that provide international organisations, governments, and communities the evidence base for policy and practice that ensures health for all workers. We argue that these monitoring systems must respond to changing working environments by expanding capture of workers’ rights, working conditions, and health inequalities. We outline normative data and monitoring products to reach this systemic shift and provide the public health vision for this new direction. | | No worker should die or get ill because of their work, or be left behind in occupational health protection and promotion. All workers are entitled to the human rights to: health;6 a clean, healthy, and sustainable environment; and a safe and healthy working environment.7 However, WHO and the International Labour Organization (ILO) estimate that annually 2 million deaths and 90 million disability-adjusted life-years are attributable to selected occupational risk factors.8 Recognition is growing that improving workers’ health and health equity requires action on the social and environmental determinants of health. Examples include strengthened evidence on the effects of the emerging psychosocial hazard of long working hours on cardiovascular disease,9 and the environmental and climate crises strengthening attention to workers’ environmental and climatic hazards (eg, air pollution and heat exposures). Occupational health policy increasingly comprises health equity analysis and targets. The WHO/ILO joint estimates show geographical and socioeconomic health inequalities—an increased number of deaths is noted among workers in Africa, South-East Asia, and the Western Pacific, and among men and people aged 55 years or older.8 People working in the informal economy, and migrant, outdoor, and front-line workers are often especially disadvantaged. Health-care workers, despite working in a sector that aims to restore, protect, and promote health, often face hazardous working conditions and are exposed to pathogens (eg, SARS-CoV-2), violence, and long working hours, among others. Ongoing changes in working environments (eg, globalisation, automation, digitisation, new pandemics, environmental pollution, and climate change) exacerbate these inequalities. Ultimately, unhealthy working conditions act as barriers for realising workers’ rights to health, population health, and health equity, and threaten the goal of achieving the SDGs globally. |
Evaluating event-based surveillance capacity in Africa: Use of the Africa CDC scorecard, 2022-2023
Tetuh KM , Salyer SJ , Aliddeki D , Tibebu B , Osman F , Amabo FC , Warren LK , Buba MI , Kebede Y . Prev Med Rep 2023 36 102398 INTRODUCTION: Event-based surveillance (EBS) is a critical component of Early Warning, Alert and Response (EWAR) capacity needed for outbreak prevention and control. To better understand existing EBS and monitor the progress of capacity-building efforts over time, Africa CDC developed an EBS scorecard as part of a revision to the EBS Framework. METHODS: We distributed the scorecard to African Union (AU) Member States (MSs). Survey responses from the MSs' human health sector were aggregated, cleaned, and analysed. MS, regional, and continental EBS capacity was assessed. RESULTS: Between 21 July 2022 and 4 April 2023, a total of 63 respondents representing 49 (89%) of 55 MSs completed the survey. Given Africa CDC's public health mandate, we acknowledged the importance of One Health collaboration in MSs but focused on and analysed only the human health sector responses. Thirty-four (71%) MSs stated having EBS in place; hotline was the most common type of EBS implemented (76%). Seventeen (50%) MSs reported multisectoral, One Health collaboration as part of EBS implementation. Scorecard outcomes showed a minimal (score of <60%) to average (score between 60-80%) level of EBS capacity in 29 and five (5) MSs respectively. DISCUSSION: Current EBS capacity levels need to be strengthened in Africa to ensure the continent remains prepared for future public health threats. The Africa CDC EBS scorecard provides a useful way to measure and track this capacity over time. Results can be used to advocate for and target resources for capacity building to foster public health emergency preparedness efforts. |
N-glycosylation profiles of the SARS-CoV-2 spike D614G mutant and its ancestral protein characterized by advanced mass spectrometry (preprint)
Wang D , Zhou B , Keppel TR , Solano M , Baudys J , Goldstein J , Finn MG , Fan X , Chapman AP , Bundy JL , Woolfitt AR , Osman SH , Pirkle JL , Wentworth DE , Barr JR . bioRxiv 2021 2021.07.26.453787 N-glycosylation plays an important role in the structure and function of membrane and secreted proteins. The spike protein on the surface of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19, is heavily glycosylated and the major target for developing vaccines, therapeutic drugs and diagnostic tests. The first major SARS-CoV-2 variant carries a D614G substitution in the spike (S-D614G) that has been associated with altered conformation, enhanced ACE2 binding, and increased infectivity and transmission. In this report, we used mass spectrometry techniques to characterize and compare the N-glycosylation of the wild type (S-614D) or variant (S-614G) SARS-CoV-2 spike glycoproteins prepared under identical conditions. The data showed that half of the N-glycosylation sequons changed their distribution of glycans in the S-614G variant. The S-614G variant showed a decrease in the relative abundance of complex-type glycans (up to 45%) and an increase in oligomannose glycans (up to 33%) on all altered sequons. These changes led to a reduction in the overall complexity of the total N-glycosylation profile. All the glycosylation sites with altered patterns were in the spike head while the glycosylation of three sites in the stalk remained unchanged between S-614G and S-614D proteins.Competing Interest StatementThe authors have declared no competing interest. |
Analysis of the N-glycosylation profiles of the spike proteins from the Alpha, Beta, Gamma, and Delta variants of SARS-CoV-2
Wang D , Baudys J , Osman SH , Barr JR . Anal Bioanal Chem 2023 415 (19) 4779-4793 N-Glycosylation plays an important role in the structure and function of membrane and secreted proteins. Viral proteins used in cell entry are often extensively glycosylated to assist in protein folding, provide stability, and shield the virus from immune recognition by its host (described as a "glycan shield"). The SARS-CoV-2 spike protein (S) is a prime example, having 22 potential sites of N-glycosylation per protein protomer, as predicted from the primary sequence. In this report, we conducted mass spectrometric analysis of the N-glycosylation profiles of recombinant spike proteins derived from four common SARS-CoV-2 variants classified as Variant of Concern, including Alpha, Beta, Gamma, and Delta along with D614G variant spike as a control. Our data reveal that the amino acid substitutions and deletions between variants impact the abundance and type of glycans on glycosylation sites of the spike protein. Some of the N-glycosylation sequons in S show differences between SARS-CoV-2 variants in the distribution of glycan forms. In comparison with our previously reported site-specific glycan analysis on the S-D614G and its ancestral protein, glycan types on later variants showed high similarity on the site-specific glycan content to S-D614G. Additionally, we applied multiple digestion methods on each sample, and confirmed the results for individual glycosylation sites from different experiment conditions to improve the identification and quantification of glycopeptides. Detailed site-specific glycan analysis of a wide variety of SARS-CoV-2 variants provides useful information toward the understanding of the role of protein glycosylation on viral protein structure and function and development of effective vaccines and therapeutics. |
In elimination settings, measles antibodies wane following vaccination but not following infection - a systematic review and meta-analysis
Bolotin S , Osman S , Hughes SL , Ariyarajah A , Tricco AC , Khan S , Li L , Johnson C , Friedman L , Gul N , Jardine R , Faulkner M , Hahné SJM , Heffernan JM , Dabbagh A , Rota PA , Severini A , Jit M , Durrheim DN , Orenstein WA , Moss WJ , Funk S , Turner N , Schluter W , Jawad JS , Crowcroft NS . J Infect Dis 2022 226 (7) 1127-1139 BACKGROUND: We conducted a systematic review to assess whether measles humoral immunity wanes in previously infected or vaccinated populations in measles elimination settings. METHODS: After screening 16,822 citations, we identified nine articles from populations exposed to wild-type measles and 16 articles from vaccinated populations that met our inclusion criteria. RESULTS: Using linear regression, we found that geometric mean titers (GMTs) decreased significantly in individuals who received two doses of measles-containing vaccine (MCV) by 121.8 mIU/mL (95% CI -212.4, -31.1) per year since vaccination over one to five years, 53.7 mIU/mL (95% CI -95.3, -12.2) five to ten years, 33.2 mIU/mL (95% CI -62.6, -3.9) ten to 15 years, and 24.1 mIU/mL (95% CI -51.5,3.3) 15 to 20 years since vaccination. Decreases in GMT over time were not significant after one dose of MCV or after infection. Decreases in the proportion of seropositive individuals over time were not significant after one or two doses of MCV, or after infection. CONCLUSIONS: Measles antibody waning in vaccinated populations should be considered in planning for measles elimination. |
Genital immune cell activation and tenofovir gel efficacy: a case-control study
Liebenberg LJP , Passmore JS , Osman F , Jewanraj J , Mtshali A , Garcia-Lerma JG , Heneine W , Holder A , Archary D , Ngcapu S , Sivro A , Mansoor LE , Abdool Karim Q , Abdool Karim SS , McKinnon LR . Clin Infect Dis 2022 75 (6) 1088-1091 Genital inflammation (GI) undermines topical HIV pre-exposure prophylaxis (PrEP) efficacy through unknown mechanisms. Here, associations between activated endocervical CD4+ T cell numbers and higher deoxyadenosine triphosphate (dATP) concentrations suggest that competition for intracellular metabolites within HIV target cells may reduce the efficacy of antiretroviral-based PrEP in women with GI. |
Risk factors for Brucellosis and knowledge-attitude practice among pastoralists in Afar and Somali regions of Ethiopia
Tschopp R , GebreGiorgis A , Abdulkadir O , Molla W , Hamid M , Tassachew Y , Andualem H , Osman M , Waqjira MW , Mohammed A , Negron M , Walke H , Kadzik M , Mamo G . Prev Vet Med 2022 199 105557 BACKGROUND: Brucellosis is a neglected bacterial zoonotic disease with substantial economic impact on households. Pastoral communities are a potential risk group due to their way of life being closely interlinked with their large livestock herds. METHODOLOGY: A semi-structured questionnaire survey was conducted in households in the pastoral Afar and Somali (SRS) regions. All households had people and animals serologically tested for brucellosis. Questions were related to husbandry, consumption habits, and knowledge-attitude-practice towards the disease and zoonoses. Descriptive statistics and logistic analysis were performed to assess potential risk factors for having households with positive humans and/or animals. RESULT: 647 households were included in the survey. Herd brucellosis prevalence was 40.3 % (15.9-86.3 % in Afar; 4-72.2 % in SRS). Over half (56.3 %) of the households in Afar and 41.8 % in SRS had at least one human reactor. Nearly a quarter of the households (22.8 %), recalled abortions in goats in the last 12 months, whereas 52.5 % and 50.3 % recalled stillborn in all species and membrane retentions respectively. All respondents drank raw milk and discarded animal afterbirths in the direct surroundings with minimal protection. Risk factors for animal reactors were goat herd size, and goat abortion. There was no identified risk factor for having human reactors in households. None of the households knew about brucellosis. CONCLUSION: Although being endemic in Afar and SRS, Brucellosis is not known by the pastoralists. Brucellosis control programs will have to be tailored to the pastoral context, accounting for their mobility, large, multi-species herds and habits. |
Enhanced fitness of SARS-CoV-2 variant of concern Alpha but not Beta.
Ulrich L , Halwe NJ , Taddeo A , Ebert N , Schön J , Devisme C , Trüeb BS , Hoffmann B , Wider M , Fan X , Bekliz M , Essaidi-Laziosi M , Schmidt ML , Niemeyer D , Corman VM , Kraft A , Godel A , Laloli L , Kelly JN , Calderon BM , Breithaupt A , Wylezich C , Veiga IB , Gultom M , Osman S , Zhou B , Adea K , Meyer B , Eberhardt C , Thomann L , Gsell M , Labroussaa F , Jores J , Summerfield A , Drosten C , Eckerle IA , Wentworth DE , Dijkman R , Hoffmann D , Thiel V , Beer M , Benarafa C . Nature 2021 602 (7896) 307-313 Emerging variants of concern (VOC) drive the SARS-CoV-2 pandemic(1,2). Experimental assessment of replication and transmission of major VOC compared to progenitors are needed to understand successful emerging mechanisms of VOC(3). Here, we show that Alpha and Beta spike (S) proteins have a greater affinity to human angiotensin converting enzyme 2 (hACE2) receptor over the progenitor variant (wt-S(614G)) in vitro. Yet Alpha and wt-S(614G) had similar replication kinetics in human nasal airway epithelial cultures, whereas Beta was outcompeted by both. In vivo, competition experiments showed a clear fitness advantage of Alpha over the progenitor variant (wt-S(614G)) in ferrets and two mouse models, where the substitutions in S were major drivers for fitness advantage. In hamsters, supporting high replication levels, Alpha and wt-S(614G) had comparable fitness. In contrast, Beta was outcompeted by Alpha and wt-S(614G) in hamsters and hACE2-expressing mice. Our study highlights the importance of using multiple models for complete fitness characterization of VOC and demonstrates adaptation of Alpha towards increased upper respiratory tract replication and enhanced transmission in vivo in restrictive models, whereas Beta fails to overcome contemporary strains in naïve animals. |
N-glycosylation profiles of the SARS-CoV-2 spike D614G mutant and its ancestral protein characterized by advanced mass spectrometry.
Wang D , Zhou B , Keppel TR , Solano M , Baudys J , Goldstein J , Finn MG , Fan X , Chapman AP , Bundy JL , Woolfitt AR , Osman SH , Pirkle JL , Wentworth DE , Barr JR . Sci Rep 2021 11 (1) 23561 N-glycosylation plays an important role in the structure and function of membrane and secreted proteins. The spike protein on the surface of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19, is heavily glycosylated and the major target for developing vaccines, therapeutic drugs and diagnostic tests. The first major SARS-CoV-2 variant carries a D614G substitution in the spike (S-D614G) that has been associated with altered conformation, enhanced ACE2 binding, and increased infectivity and transmission. In this report, we used mass spectrometry techniques to characterize and compare the N-glycosylation of the wild type (S-614D) or variant (S-614G) SARS-CoV-2 spike glycoproteins prepared under identical conditions. The data showed that half of the N-glycosylation sequons changed their distribution of glycans in the S-614G variant. The S-614G variant showed a decrease in the relative abundance of complex-type glycans (up to 45%) and an increase in oligomannose glycans (up to 33%) on all altered sequons. These changes led to a reduction in the overall complexity of the total N-glycosylation profile. All the glycosylation sites with altered patterns were in the spike head while the glycosylation of three sites in the stalk remained unchanged between S-614G and S-614D proteins. |
Integrated human-animal sero-surveillance of Brucellosis in the pastoral Afar and Somali regions of Ethiopia
Tschopp R , Gebregiorgis A , Tassachew Y , Andualem H , Osman M , Waqjira MW , Hattendorf J , Mohammed A , Hamid M , Molla W , Mitiku SA , Walke H , Negron M , Kadzik M , Mamo G . PLoS Negl Trop Dis 2021 15 (8) e0009593 BACKGROUND: Brucellosis is widespread in Ethiopia with variable reported prevalence depending on the geographical area, husbandry practices and animal species. However, there is limited information on the disease prevalence amongst pastoral communities, whose life is intricately linked with their livestock. METHODOLOGY: We conducted an integrated human-animal brucellosis sero-surveillance study in two adjacent pastoral regions, Afar and Somali region (SRS). This cross-sectional study included 13 woredas (districts) and 650 households. Blood samples were collected from people and livestock species (cattle, camel, goats and sheep). Sera were analyzed with C-ELISA for camels and shoats (sheep and goats), with I-ELISA for cattle and IgG ELISA for humans. Descriptive and inferential statistics analyses were performed. RESULTS: A total of 5469 sera were tested by ELISA. Prevalence of livestock was 9.0% in Afar and 8.6% in SRS (ranging from 0.6 to 20.2% at woreda level). In humans, prevalence was 48.3% in Afar and 34.9% in SRS (ranging from 0.0 to 74.5% at woreda level). 68.4% of all households in Afar and 57.5% of households in SRS had at least one animal reactor. Overall, 4.1% of animals had a history of abortion. The proportion of animals with abortion history was higher in seropositive animals than in seronegative animals. Risk factor analysis showed that female animals were significantly at higher risk of being reactors (p = 0.013). Among the species, cattle had the least risk of being reactors (p = 0.014). In humans, there was a clear regional association of disease prevalence (p = 0.002). The older the people, the highest the odds of being seropositive. CONCLUSION: Brucellosis is widespread in humans and animals in pastoral communities of Afar and SRS with the existence of geographical hotspots. No clear association was seen between human and particular livestock species prevalence, hence there was no indication as whether B. abortus or B. melitensis are circulating in these areas, which warrants further molecular research prior to embarking on a national control programs. Such programs will need to be tailored to the pastoral context. |
Treatment outcomes in global systematic review and patient meta-analysis of children with extensively drug-resistant tuberculosis
Osman M , Harausz EP , Garcia-Prats AJ , Schaaf HS , Moore BK , Hicks RM , Achar J , Amanullah F , Barry P , Becerra M , Chiotan DI , Drobac PC , Flood J , Furin J , Gegia M , Isaakidis P , Mariandyshev A , Ozere I , Shah NS , Skrahina A , Yablokova E , Seddon JA , Hesseling AC . Emerg Infect Dis 2019 25 (3) 441-450 Extensively drug-resistant tuberculosis (XDR TB) has extremely poor treatment outcomes in adults. Limited data are available for children. We report on clinical manifestations, treatment, and outcomes for 37 children (<15 years of age) with bacteriologically confirmed XDR TB in 11 countries. These patients were managed during 1999-2013. For the 37 children, median age was 11 years, 32 (87%) had pulmonary TB, and 29 had a recorded HIV status; 7 (24%) were infected with HIV. Median treatment duration was 7.0 months for the intensive phase and 12.2 months for the continuation phase. Thirty (81%) children had favorable treatment outcomes. Four (11%) died, 1 (3%) failed treatment, and 2 (5%) did not complete treatment. We found a high proportion of favorable treatment outcomes among children, with mortality rates markedly lower than for adults. Regimens and duration of treatment varied considerably. Evaluation of new regimens in children is required. |
Mixed methods evaluation explains bypassing of vouchers in micronutrient powder trial in Mozambique
Tumilowicz A , Vossenaar M , Kjaer K , Vettersand J , Possolo E , Pelto GH , Jefferds ME , Norte A , Dos Santos Dias K , Osman N , Gonzalez W , Poonawala A , Neufeld LM . Matern Child Nutr 2019 15 e12718 Micronutrient powders (MNP) are recommended by the World Health Organization as an effective intervention to address anaemia in children. A formative process evaluation was conducted to assess the viability of a model using free vouchers in two districts of Mozambique to deliver MNP and motivate adherence to recommendations regarding its use. The evaluation consisted of (a) an examination of programme outcomes using a cross-sectional survey among caregivers of children 6-23 months (n = 1,028) and (b) an ethnographic study to investigate delivery experiences and MNP use from caregiver perspectives (n = 59), programme managers (n = 17), and programme implementers (n = 168). Using a mixed methods approach allowed exploration of unexpected programme outcomes and triangulation of findings. The survey revealed that receiving a voucher was the main implementation bottleneck. Although few caregivers received vouchers (11.5%, CI [9.7, 13.6]), one-fourth received MNP by bypassing the voucher system (26.3%, CI [23.6, 29.0]). Caregivers' narratives indicated that caregivers were motivated to redeem vouchers but encountered obstacles, including not knowing where or how to redeem them or finding MNP were not available at the shop. Observing these challenges, many programme implementers redeemed vouchers and distributed MNP to caregivers. Virtually, all caregivers who received MNP reported ever feeding it to their child. This study's findings are consistent with other studies across a range of contexts suggesting that although programmes are generally effective in motivating initial use, more attention is required to improve access to MNP and support continued use. |
Scope and extent of healthcare-associated Middle East respiratory syndrome coronavirus transmission during two contemporaneous outbreaks in Riyadh, Saudi Arabia, 2017.
Alanazi KH , Killerby ME , Biggs HM , Abedi GR , Jokhdar H , Alsharef AA , Mohammed M , Abdalla O , Almari A , Bereagesh S , Tawfik S , Alresheedi H , Alhakeem RF , Hakawi A , Alfalah H , Amer H , Thornburg NJ , Tamin A , Trivedi S , Tong S , Lu X , Queen K , Li Y , Sakthivel SK , Tao Y , Zhang J , Paden CR , Al-Abdely HM , Assiri AM , Gerber SI , Watson JT . Infect Control Hosp Epidemiol 2019 40 (1) 79-88 OBJECTIVE: To investigate a Middle East respiratory syndrome coronavirus (MERS-CoV) outbreak event involving multiple healthcare facilities in Riyadh, Saudi Arabia; to characterize transmission; and to explore infection control implications. DESIGN: Outbreak investigation. SETTING: Cases presented in 4 healthcare facilities in Riyadh, Saudi Arabia: a tertiary-care hospital, a specialty pulmonary hospital, an outpatient clinic, and an outpatient dialysis unit. METHODS: Contact tracing and testing were performed following reports of cases at 2 hospitals. Laboratory results were confirmed by real-time reverse transcription polymerase chain reaction (rRT-PCR) and/or genome sequencing. We assessed exposures and determined seropositivity among available healthcare personnel (HCP) cases and HCP contacts of cases. RESULTS: In total, 48 cases were identified, involving patients, HCP, and family members across 2 hospitals, an outpatient clinic, and a dialysis clinic. At each hospital, transmission was linked to a unique index case. Moreover, 4 cases were associated with superspreading events (any interaction where a case patient transmitted to >/=5 subsequent case patients). All 4 of these patients were severely ill, were initially not recognized as MERS-CoV cases, and subsequently died. Genomic sequences clustered separately, suggesting 2 distinct outbreaks. Overall, 4 (24%) of 17 HCP cases and 3 (3%) of 114 HCP contacts of cases were seropositive. CONCLUSIONS: We describe 2 distinct healthcare-associated outbreaks, each initiated by a unique index case and characterized by multiple superspreading events. Delays in recognition and in subsequent implementation of control measures contributed to secondary transmission. Prompt contact tracing, repeated testing, HCP furloughing, and implementation of recommended transmission-based precautions for suspected cases ultimately halted transmission. |
Anti-bacterial efficacy of alcoholic hand rubs in the Kenyan market, 2015
Ochwoto M , Muita L , Talaam K , Wanjala C , Ogeto F , Wachira F , Osman S , Kimotho J , Ndegwa L . Antimicrob Resist Infect Control 2017 6 17 BACKGROUND: Hand hygiene is known to be effective in preventing hospital and community-acquired infections. The increasing number of hand sanitizer brands in Kenyan hospitals and consumer outlets is of concern. Thus the main aim of this study was to evaluate the anti-bacterial efficacy and organoleptic properties of these hand sanitizers in Kenya. METHODS: This was an experimental, laboratory-based study of 14 different brands of hand sanitizers (coded HS1-14) available in various retail outlets and hospitals in Kenya. Efficacy was evaluated using standard non-pathogenic Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 25923) and Pseudomonas aeruginosa (ATCC 27853) as per the European Standard (EN). The logarithmic reduction factors (RF) were assessed at baseline and after treatment, and log reduction then calculated. Ten and 25 healthy volunteers participated in the efficacy and organoleptic studies respectively. RESULTS: Four (28.6%) hand sanitizers (HS12, HS9, HS13 and HS14) showed a 5.9 reduction factor on all the three bacteria strains. Seven (50%) hand sanitizers had efficacies of <3 against all the three bacteria strains used. Efficacy on E. Coli was higher compared to the other pathogens. Three hand sanitizers were efficacious on one of the pathogens and not the other. In terms of organoleptic properties, gel-based formulations were rated far higher than the liquid based formulations brands. CONCLUSION: Fifty percent (50%) of the selected hand sanitizers in the Kenyan market have efficacy that falls below the World Health Organization (WHO) and DIN EN 1500:2013. Of the 14 hand sanitizers found in the Kenyan market, only four showed efficacies that were comparable to the WHO-formulation. There is a need to evaluate how many of these products with <3 efficacy that have been incorporated into the health system for hand hygiene and the country's policy on regulations on their usage. |
Increase in Middle East Respiratory Syndrome-Coronavirus Cases in Saudi Arabia Linked to Hospital Outbreak With Continued Circulation of Recombinant Virus, July 1-August 31, 2015.
Assiri AM , Biggs HM , Abedi GR , Lu X , Bin Saeed A , Abdalla O , Mohammed M , Al-Abdely HM , Algarni HS , Alhakeem RF , Almasri MM , Alsharef AA , Nooh R , Erdman DD , Gerber SI , Watson JT . Open Forum Infect Dis 2016 3 (3) ofw165 During July-August 2015, the number of cases of Middle East respiratory syndrome (MERS) reported from Saudi Arabia increased dramatically. We reviewed the 143 confirmed cases from this period and classified each based upon likely transmission source. We found that the surge in cases resulted predominantly (90%) from secondary transmission largely attributable to an outbreak at a single healthcare facility in Riyadh. Genome sequencing of MERS coronavirus from 6 cases demonstrated continued circulation of the recently described recombinant virus. A single unique frameshift deletion in open reading frame 5 was detected in the viral sequence from 1 case. |
Spike gene deletion quasispecies in serum of patient with acute MERS-CoV infection.
Lu X , Rowe LA , Frace M , Stevens J , Abedi GR , El Nile O , Banassir T , Al-Masri M , Watson JT , Assiri A , Erdman DD . J Med Virol 2016 89 (3) 542-545 The spike glycoprotein of the Middle East respiratory coronavirus (MERS-CoV) facilitates receptor binding and cell entry. During investigation of a multi-facility outbreak of MERS-CoV in Taif, Saudi Arabia, we identified a mixed population of wild-type and variant sequences with a large 530 nucleotide deletion in the spike gene from the serum of one patient. The out of frame deletion predicted loss of most of the S2 subunit of the spike protein leaving the S1 subunit with an intact receptor binding domain. This finding documents human infection with a novel genetic variant of MERS-CoV present as a quasispecies. |
Epidemiology of a Novel Recombinant MERS-CoV in Humans in Saudi Arabia.
Assiri AM , Midgley CM , Abedi GR , Bin Saeed A , Almasri MM , Lu X , Al-Abdely HM , Abdalla O , Mohammed M , Algarni HS , Alhakeem RF , Sakthivel SK , Nooh R , Alshayab Z , Alessa M , Srinivasamoorthy G , AlQahtani SY , Kheyami A , HajOmar WH , Banaser TM , Esmaeel A , Hall AJ , Curns AT , Tamin A , Alsharef AA , Erdman D , Watson JT , Gerber SI . J Infect Dis 2016 214 (5) 712-21 BACKGROUND: The Middle East respiratory syndrome coronavirus (MERS-CoV) causes severe respiratory illness in humans. Fundamental questions about circulating viruses and transmission routes remain. METHODS: We assessed routinely collected epidemiologic data for MERS-CoV cases reported in Saudi Arabia during January 01 - June 30, 2015, and conducted a more detailed investigation of cases reported during February 2015. Available respiratory specimens were obtained for sequencing. RESULTS: During the study period, 216 MERS-CoV cases were reported. Spike gene or full genome sequences (n=17) were obtained from 99 individuals. Most (72 of 99, 73%) sequences formed a discrete, novel recombinant clade (NRC-2015), which was detected in 6 regions and became predominant by June, 2015. No clinical differences were noted between clades. Among 87 cases reported during February 2015, 13 had no recognized risks for secondary acquisition; 12 of these 13 also denied camel contact. Most viruses (8 of 9) from these 13 individuals belonged to NRC-2015. DISCUSSION: Our findings document the spread and eventual predominance of NRC-2015 in humans in Saudi Arabia during the first half of 2015. Our identification of cases without recognized risk factors but with similar virus sequences suggests that additional study is needed to better understand risk factors for MERS-CoV infection. |
HIV type 1 gag genetic diversity among antenatal clinic attendees in North Rift Valley, Kenya.
Nyagaka B , Kiptoo MK , Lihana RW , Khamadi SA , Makokha EP , Kinyua JG , Mwangi J , Osman S , Lagat NJ , Muriuki J , Okoth V , Gicheru M , Ng'ang'a Z , Songok EM . AIDS Res Hum Retroviruses 2012 28 (5) 523-6 HIV genetic recombination and high mutation rate increase diversity allowing it to escape from host immune response or antiretroviral drugs. This diversity has enabled specific viral subtypes to be predominant in specific regions. To determine HIV-1 subtypes among seropositive antenatal clinic attendees in Kenya's North Rift Valley, a cross-sectional study was carried out on 116 HIV-1-positive blood samples. Proviral DNA was extracted from peripheral blood mononuclear cells by DNAzol lysis and ethanol precipitation. Polymerase chain reactions using specific primers for HIV-1 gag and population sequencing on resulting amplicons were carried out. Phylogenetic analysis revealed that 81 (70%) were subtype A1, 13 (11%) subtype D, 8 (7%) subtype C, 3 (3%) subtype A2, 1 (1%) subtype G, and 10 showed possible recombinants: 5 (4%) subtype A1D, 4 (3%) subtype A1C, and 1 (1%) subtype A2C. These data support the need to establish circulating subtypes for better evaluation of effective HIV diagnostic and treatment options in Kenya. |
Effects of ivermectin on blood-feeding Phlebotomus papatasi, and the promastigote stage of Leishmania major
Hanafi HA , Szumlas DE , Fryauff DJ , El-Hossary SS , Singer GA , Osman SG , Watany N , Furman BD , Hoel DF . Vector Borne Zoonotic Dis 2011 11 (1) 43-52 Ivermectin (IVM) is a chemically modified macrocyclic lactone of Streptomyces avermitilis that acts as a potent neurotoxin against many nematodes and arthropods. Little is known of IVM's effect against either blood-feeding Phlebotomus sand flies, or the infective promastigote stage of Leishmania transmitted by these flies. We injected hamsters subcutaneously with two standard IVM treatments (200 and 400 mug/kg body weight) and allowed cohorts of Leishmania major-infected Phlebotomus papatasi to blood-feed on these animals at various posttreatment time points (4 h, 1, 2, 6, and 10 days). Infected and uninfected sand flies that bit treated and untreated hamsters served as controls. Serum levels of IVM in low- and high-dose-treated hamsters were determined at the five time points. Sand fly mortality following blood feeding was recorded at 24-h intervals and, in relation to IVM treatment, was time and dose dependent. Mortality was most rapid and greatest among infected flies that fed nearest to time of dosing. Mean survival of infected sand flies after feeding on untreated hamsters was 11.5 days, whereas that of infected sand flies that fed 4 h, 1 day, or 2 days posttreatment on high-dose-treated hamsters (400 mug/kg) was 1.6, 2.1, and 2.7 days, respectively. Infected and uninfected sand flies that blood fed 6 days following low-dose IVM treatment (200 mug/kg) still experienced significantly greater mortality (p < 0.02) than controls. Promastigotes dissected out of surviving flies that fed on IVM-treated hamsters showed typical motility and survival. Moreover, 21.7% of IVM-treated hamsters developed lesions after being fed upon by infected sand flies. L. major promastigotes appeared to be tolerant to ng/mL blood levels of IVM that caused significant mortality for up to 10 days posttreatment in blood-feeding P. papatasi. |
Household-based sero-epidemiologic survey after a yellow fever epidemic, Sudan, 2005
Farnon EC , Gould LH , Griffith KS , Osman MS , Kholy AE , Brair ME , Panella AJ , Kosoy O , Laven JJ , Godsey MS , Perea W , Hayes EB . Am J Trop Med Hyg 2010 82 (6) 1146-52 From September through early December 2005, an outbreak of yellow fever (YF) occurred in South Kordofan, Sudan, resulting in a mass YF vaccination campaign. In late December 2005, we conducted a serosurvey to assess YF vaccine coverage and to better define the epidemiology of the outbreak in an index village. Of 552 persons enrolled, 95% reported recent YF vaccination, and 25% reported febrile illness during the outbreak period: 13% reported YF-like illness, 4% reported severe YF-like illness, and 12% reported chikungunya-like illness. Of 87 persons who provided blood samples, all had positive YF serologic results, including three who had never been vaccinated. There was also serologic evidence of recent or prior chikungunya virus, dengue virus, West Nile virus, and Sindbis virus infections. These results indicate that YF virus and chikungunya virus contributed to the outbreak. The high prevalence of YF antibody among vaccinees indicates that vaccination was effectively implemented in this remotely located population. |
- Page last reviewed:Feb 1, 2024
- Page last updated:Apr 29, 2024
- Content source:
- Powered by CDC PHGKB Infrastructure