Last data update: Apr 18, 2025. (Total: 49119 publications since 2009)
Records 1-5 (of 5 Records) |
Query Trace: Fischer-Walker C[original query] |
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Male partner age, viral load, and HIV infection in adolescent girls and young women: Evidence from eight sub-Saharan African countries
Ayton S , Schwitters A , Mantell JE , Nuwagaba-Biribonwoha H , Hakim A , Hoffman S , Biraro S , Philip N , Wiesner L , Gummerson E , Brown K , Nyogea D , Barradas D , Nzima M , Fischer-Walker C , Payne D , Mulenga L , Mgomella G , Kirungi WL , Maile L , Aibo D , Dvm GM , Mugurungi O , Low A . AIDS 2022 37 (1) 113-123 OBJECTIVE: We aimed to elucidate the role of partnerships with older men in the HIV epidemic among adolescent girls and young women (AGYW) aged 15-24 years in sub-Saharan Africa. DESIGN: Analysis of Population-based HIV Impact Assessments (PHIAs) in Eswatini, Lesotho, Malawi, Namibia, Tanzania, Uganda, Zambia, and Zimbabwe. METHODS: We examined associations between reported partner age and recent HIV infection among AGYW, incorporating male population-level HIV characteristics by age-band. Recent HIV infection was defined using the LAg avidity assay algorithm. Viremia was defined as a viral load >1000 copies/ml, regardless of serostatus. Logistic regression compared recent infection in AGYW with older male partners to those reporting younger partners. Dyadic analysis examined cohabitating male partner age, HIV status, and viremia to assess associations with AGYW infection. RESULTS: Among 17,813 AGYW, increasing partner age was associated with higher odds of recent infection, peaking for partners aged 35-44 (adjusted odds ratio (aOR)=8.94, 95% CI: 2.63-30.37) compared to partners aged 15-24. Population-level viremia was highest in this male age-band. Dyadic analyses of 5,432 partnerships confirmed the association between partner age-band and prevalent HIV infection (male spousal age 35-44- aOR=3.82, 95% CI: 2.17-6.75). Most new infections were in AGYW with partners aged 25-34, as most AGYW had partners in this age-band. CONCLUSIONS: These results provide evidence that men aged 25-34 drive most AGYW infections, but partners over 9 years older than AGYW in the 35-44 age-band confer greater risk. Population-level infectiousness and male age group should be incorporated into identifying high-risk typologies in AGYW. |
National-level effectiveness of ART to prevent early mother to child transmission of HIV in Namibia
Agabu A , Baughman AL , Fischer-Walker C , de Klerk M , Mutenda N , Rusberg F , Diergaardt D , Pentikainen N , Sawadogo S , Agolory S , Dinh TH . PLoS One 2020 15 (11) e0233341 BACKGROUND: Namibia introduced the prevention of mother to child HIV transmission (MTCT) program in 2002 and lifelong antiretroviral therapy (ART) for pregnant women (option B-plus) in 2013. We sought to quantify MTCT measured at 4-12 weeks post-delivery. METHODS: During Aug 2014-Feb 2015, we recruited a nationally representative sample of 1040 pairs of mother and infant aged 4-12 weeks at routine immunizations in 60 public health clinics using two stage sampling approach. Of these, 864 HIV exposed infants had DNA-PCR HIV test results available. We defined an HIV exposed infant if born to an HIV-positive mother with documented status or diagnosed at enrollment using rapid HIV tests. Dried Blood Spots samples from HIV exposed infants were tested for HIV. Interview data and laboratory results were collected on smartphones and uploaded to a central database. We measured MTCT prevalence at 4-12 weeks post-delivery and evaluated associations between infant HIV infection and maternal and infant characteristics including maternal treatment and infant prophylaxis. All statistical analyses accounted for the survey design. RESULTS: Based on the 864 HIV exposed infants with test results available, nationally weighted early MTCT measured at 4-12 weeks post-delivery was 1.74% (95% confidence interval (CI): 1.00%-3.01%). Overall, 62% of mothers started ART pre-conception, 33.6% during pregnancy, 1.2% post-delivery and 3.2% never received ART. Mothers who started ART before pregnancy and during pregnancy had low MTCT prevalence, 0.78% (95% CI: 0.31%-1.96%) and 0.98% (95% CI: 0.33%-2.91%), respectively. MTCT rose to 4.13% (95% CI: 0.54%-25.68%) when the mother started ART after delivery and to 11.62% (95% CI: 4.07%-28.96%) when she never received ART. The lowest MTCT of 0.76% (95% CI: 0.36% - 1.61%) was achieved when mother received ART and ARV prophylaxis within 72hrs for infant and highest 22.32% (95%CI: 2.78% -74.25%) when neither mother nor infant received ARVs. After adjusting for mother's age, maternal ART (Prevalence Ratio (PR) = 0.10, 95% CI: 0.03-0.29) and infant ARV prophylaxis (PR = 0.32, 95% CI: 0.10-0.998) remained strong predictors of HIV transmission. CONCLUSION: As of 2015, Namibia achieved MTCT of 1.74%, measured at 4-12 weeks post-delivery. Women already on ART pre-conception had the lowest prevalence of MTCT emphasizing the importance of early HIV diagnosis and treatment initiation before pregnancy. Studies are needed to measure MTCT and maternal HIV seroconversion during breastfeeding. |
Introduction of an Alcohol-Related Electronic Screening and Brief Intervention (eSBI) Program to reduce hazardous alcohol consumption in Namibia's antiretroviral treatment (ART) program
Tang AM , Hamunime N , Adams RA , Kanyinga G , Fischer-Walker C , Agolory S , Prybylski D , Mutenda N , Sughrue S , Walker DD , Rennie T , Zahralban-Steele M , Kerrigan A , Hong SY . AIDS Behav 2019 23 (11) 3078-3092 Alcohol is the most widely abused substance in Namibia and is associated with poor adherence and retention in care among people on antiretroviral therapy (ART). Electronic screening and brief interventions (eSBI) are effective in reducing alcohol consumption in various contexts. We used a mixed methods approach to develop, implement, and evaluate the introduction of an eSBI in two ART clinics in Namibia. Of the 787 participants, 45% reported some alcohol use in the past 12 months and 25% reported hazardous drinking levels. Hazardous drinkers were more likely to be male, separated/widowed/divorced, have a monthly household income > $1000 NAD, and report less than excellent ART adherence. Based on qualitative feedback from participants and providers, ART patients using the eSBI for the first time found it to be a positive and beneficial experience. However, we identified several programmatic considerations that could improve the experience and yield in future implementation studies. |
World Health Organization estimates of the global and regional disease burden of 22 foodborne bacterial, protozoal, and viral diseases, 2010: a data synthesis
Kirk MD , Pires SM , Black RE , Caipo M , Crump JA , Devleesschauwer B , Dopfer D , Fazil A , Fischer-Walker CL , Hald T , Hall AJ , Keddy KH , Lake RJ , Lanata CF , Torgerson PR , Havelaar AH , Angulo FJ . PLoS Med 2015 12 (12) e1001921 BACKGROUND: Foodborne diseases are important worldwide, resulting in considerable morbidity and mortality. To our knowledge, we present the first global and regional estimates of the disease burden of the most important foodborne bacterial, protozoal, and viral diseases. METHODS AND FINDINGS: We synthesized data on the number of foodborne illnesses, sequelae, deaths, and Disability Adjusted Life Years (DALYs), for all diseases with sufficient data to support global and regional estimates, by age and region. The data sources included varied by pathogen and included systematic reviews, cohort studies, surveillance studies and other burden of disease assessments. We sought relevant data circa 2010, and included sources from 1990-2012. The number of studies per pathogen ranged from as few as 5 studies for bacterial intoxications through to 494 studies for diarrheal pathogens. To estimate mortality for Mycobacterium bovis infections and morbidity and mortality for invasive non-typhoidal Salmonella enterica infections, we excluded cases attributed to HIV infection. We excluded stillbirths in our estimates. We estimate that the 22 diseases included in our study resulted in two billion (95% uncertainty interval [UI] 1.5-2.9 billion) cases, over one million (95% UI 0.89-1.4 million) deaths, and 78.7 million (95% UI 65.0-97.7 million) DALYs in 2010. To estimate the burden due to contaminated food, we then applied proportions of infections that were estimated to be foodborne from a global expert elicitation. Waterborne transmission of disease was not included. We estimate that 29% (95% UI 23-36%) of cases caused by diseases in our study, or 582 million (95% UI 401-922 million), were transmitted by contaminated food, resulting in 25.2 million (95% UI 17.5-37.0 million) DALYs. Norovirus was the leading cause of foodborne illness causing 125 million (95% UI 70-251 million) cases, while Campylobacter spp. caused 96 million (95% UI 52-177 million) foodborne illnesses. Of all foodborne diseases, diarrheal and invasive infections due to non-typhoidal S. enterica infections resulted in the highest burden, causing 4.07 million (95% UI 2.49-6.27 million) DALYs. Regionally, DALYs per 100,000 population were highest in the African region followed by the South East Asian region. Considerable burden of foodborne disease is borne by children less than five years of age. Major limitations of our study include data gaps, particularly in middle- and high-mortality countries, and uncertainty around the proportion of diseases that were foodborne. CONCLUSIONS: Foodborne diseases result in a large disease burden, particularly in children. Although it is known that diarrheal diseases are a major burden in children, we have demonstrated for the first time the importance of contaminated food as a cause. There is a need to focus food safety interventions on preventing foodborne diseases, particularly in low- and middle-income settings. |
Aetiology-specific estimates of the global and regional incidence and mortality of diarrhoeal diseases commonly transmitted through food
Pires SM , Fischer-Walker CL , Lanata CF , Devleesschauwer B , Hall AJ , Kirk MD , Duarte AS , Black RE , Angulo FJ . PLoS One 2015 10 (12) e0142927 BACKGROUND: Diarrhoeal diseases are major contributors to the global burden of disease, particularly in children. However, comprehensive estimates of the incidence and mortality due to specific aetiologies of diarrhoeal diseases are not available. The objective of this study is to provide estimates of the global and regional incidence and mortality of diarrhoeal diseases caused by nine pathogens that are commonly transmitted through foods. METHODS AND FINDINGS: We abstracted data from systematic reviews and, depending on the overall mortality rates of the country, applied either a national incidence estimate approach or a modified Child Health Epidemiology Reference Group (CHERG) approach to estimate the aetiology-specific incidence and mortality of diarrhoeal diseases, by age and region. The nine diarrhoeal diseases assessed caused an estimated 1.8 billion (95% uncertainty interval [UI] 1.1-3.3 billion) cases and 599,000 (95% UI 472,000-802,000) deaths worldwide in 2010. The largest number of cases were caused by norovirus (677 million; 95% UI 468-1,153 million), enterotoxigenic Escherichia coli (ETEC) (233 million; 95% UI 154-380 million), Shigella spp. (188 million; 95% UI 94-379 million) and Giardia lamblia (179 million; 95% UI 125-263); the largest number of deaths were caused by norovirus (213,515; 95% UI 171,783-266,561), enteropathogenic E. coli (121,455; 95% UI 103,657-143,348), ETEC (73,041; 95% UI 55,474-96,984) and Shigella (64,993; 95% UI 48,966-92,357). There were marked regional differences in incidence and mortality for these nine diseases. Nearly 40% of cases and 43% of deaths caused by these nine diarrhoeal diseases occurred in children under five years of age. CONCLUSIONS: Diarrhoeal diseases caused by these nine pathogens are responsible for a large disease burden, particularly in children. These aetiology-specific burden estimates can inform efforts to reduce diarrhoeal diseases caused by these nine pathogens commonly transmitted through foods. |
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