The Incidence Patterns Model to Estimate the Distribution of New HIV Infections in Sub-Saharan Africa: Development and Validation of a Mathematical Model.

BACKGROUND: Programmatic planning in HIV requires estimates of the distribution of new HIV infections according to identifiable characteristics of individuals. In sub-Saharan Africa, robust routine data sources and historical epidemiological observations are available to inform and validate such estimates. METHODS AND FINDINGS: We developed a predictive model, the Incidence Patterns Model (IPM), representing populations according to factors that have been demonstrated to be strongly associated with HIV acquisition risk: gender, marital/sexual activity status, geographic location, "key populations" based on risk behaviours (sex work, injecting drug use, and male-to-male sex), HIV and ART status within married or cohabiting unions, and circumcision status. The IPM estimates the distribution of new infections acquired by group based on these factors within a Bayesian framework accounting for regional prior information on demographic and epidemiological characteristics from trials or observational studies. We validated and trained the model against direct observations of HIV incidence by group in seven rounds of cohort data from four studies ("sites") conducted in Manicaland, Zimbabwe; Rakai, Uganda; Karonga, Malawi; and Kisesa, Tanzania. The IPM performed well, with the projections' credible intervals for the proportion of new infections per group overlapping the data's confidence intervals for all groups in all rounds of data. In terms of geographical distribution, the projections' credible intervals overlapped the confidence intervals for four out of seven rounds, which were used as proxies for administrative divisions in a country. We assessed model performance after internal training (within one site) and external training (between sites) by comparing mean posterior log-likelihoods and used the best model to estimate the distribution of HIV incidence in six countries (Gabon, Kenya, Malawi, Rwanda, Swaziland, and Zambia) in the region. We subsequently inferred the potential contribution of each group to transmission using a simple model that builds on the results from the IPM and makes further assumptions about sexual mixing patterns and transmission rates. In all countries except Swaziland, individuals in unions were the single group contributing to the largest proportion of new infections acquired (39%-77%), followed by never married women and men. Female sex workers accounted for a large proportion of new infections (5%-16%) compared to their population size. Individuals in unions were also the single largest contributor to the proportion of infections transmitted (35%-62%), followed by key populations and previously married men and women. Swaziland exhibited different incidence patterns, with never married men and women accounting for over 65% of new infections acquired and also contributing to a large proportion of infections transmitted (up to 56%). Between- and within-country variations indicated different incidence patterns in specific settings. CONCLUSIONS: It is possible to reliably predict the distribution of new HIV infections acquired using data routinely available in many countries in the sub-Saharan African region with a single relatively simple mathematical model. This tool would complement more specific analyses to guide resource allocation, data collection, and programme planning.

The impact of HIV on children's education in eastern Zimbabwe.

Little is known about how HIV impacts directly and indirectly on receiving, or particularly succeeding in, education in sub-Saharan Africa. To address this gap, we used multivariable logistic regression to determine the correlation between education outcomes in youth (aged 15-24) (being in the correct grade-for-age, primary school completion and having at least five "O" level passes) and being HIV-positive; having an HIV-positive parent; being a young carer; or being a maternal, paternal or double orphan, in five rounds (1998-2011) of a general population survey from eastern Zimbabwe. The fifth survey round (2009-2011) included data on children aged 6-17, which were analysed for the impacts of the above risk factors on regular attendance in primary and secondary schools and being in the correct grade-for-age. For data pooled over all rounds, being HIV-positive had no association with primary school completion, "O" level passes, or being in the correct grade-for-age in adolescents aged 16-17 years. Additionally, HIV status had no significant association with any education outcomes in children aged 6-17 surveyed in 2009-2011. In 2009-2011, being a young carer was associated with lower attendance in secondary school (69% vs. 85%, AOR: 0.44; p=0.02), whilst being a maternal (75% vs. 83%, AOR: 0.67; p<0.01), paternal (76% vs. 83%, AOR: 0.67; p=0.02) or double (75% vs. 83%, AOR: 0.68; p=0.02) orphan was associated with decreased odds of being in the correct grade-for-age. All forms of orphanhood also significantly decreased the odds of primary school completion in youths surveyed from 1998 to 2011 (all p<0.01). We found no evidence that HIV status affects education but further evidence that orphans do experience worse education outcomes than other children. Combination approaches that provide incentives for children to attend school and equip schools with tools to support vulnerable children may be most effective in improving education outcomes and should be developed and evaluated.

Prevalence of zoonotic anisakid nematodes in Inuit-harvested fish and mammals from the eastern Canadian Arctic.

Human anisakidosis is a recognized Arctic zoonosis that is directly related to the consumption of traditional Inuit foods, particularly raw fish. The epidemiology of infections with the zoonotic anisakid nematodes Anisakis simplex and Pseudoterranova decipiens was investigated from August 2007 to July 2009 in Inuit-harvested fish and marine mammals from Inuit regions of Nunavik, Nunavut, and Nunatsiavut, Canada. Fish were tested for anisakid larvae using the pepsin-HCl digestion method, and the stomachs or stomach contents of beluga whales, walruses, and three seal species were examined for anisakids. Anisakids were found in seven of eight fish species, as well as in ringed seals (18.2%; 31/170), bearded seals (75.0%; 12/16), and beluga whales (78.9%; 15/19), but not walruses (0%; 0/15). In fish, the odds of being infected with A. simplex and/or P. decipiens was 68.6 (95% confidence interval, 11.6-627.7) times higher in marine fish than in anadromous fish, after adjusting for length of fish. Negative binomial models were created for animal species with large enough sample sizes and parasite prevalence estimates to assess risk factors associated with anisakid abundance. In seals, the only risk factor significantly associated with increasing anisakid abundance was increasing length (p < 0.01), while in beluga whales, the only significant risk factor was year of capture (p = 0.03). In fish, length was the variable most commonly associated with increased anisakid larval abundance, with longer fish having significantly higher larval abundances than shorter fish of the same species. The presence of A. simplex and P. decipiens in bearded seals, ringed seals, and beluga whales from Inuit hunting grounds suggests that they likely act as definitive hosts for these parasites in these environments. With respect to zoonotic disease risk associated with Inuit country foods, among the species of fish examined, Atlantic tomcod, polar cod, and sculpins represented the greatest risk of foodborne disease from A. simplex and P. decipiens.

Migration as a risk factor for school dropout amongst children made vulnerable by HIV/AIDS: a prospective study in eastern Zimbabwe.

Orphans and other children made vulnerable by HIV in sub-Saharan Africa are at increased risk of moving household and of dropping out of school. However, the relationship between child migration and school enrolment has not been established. Multivariable regression models and prospective data from a cohort of children in Manicaland, Zimbabwe, were used to investigate the effect of migration on school enrolment. Children who had moved household were at increased risk of dropping out of school after adjusting for orphan status, relationship to primary caregiver, and household wealth. Interventions are needed to ensure that children who migrate are re-enrolled in school.

HIV in children in a general population sample in East Zimbabwe: prevalence, causes and effects.

BACKGROUND: There are an estimated half-million children living with HIV in sub-Saharan Africa. The predominant source of infection is presumed to be perinatal mother-to-child transmission, but general population data about paediatric HIV are sparse. We characterise the epidemiology of HIV in children in sub-Saharan Africa by describing the prevalence, possible source of infection, and effects of paediatric HIV in a southern African population. METHODS: From 2009 to 2011, we conducted a household-based survey of 3389 children (aged 2-14 years) in Manicaland, eastern Zimbabwe (response rate: 73.5%). Data about socio-demographic correlates of HIV, risk factors for infection, and effects on child health were analysed using multi-variable logistic regression. To assess the plausibility of mother-to-child transmission, child HIV infection was linked to maternal survival and HIV status using data from a 12-year adult HIV cohort. RESULTS: HIV prevalence was (2.2%, 95% CI: 1.6-2.8%) and did not differ significantly by sex, socio-economic status, location, religion, or child age. Infected children were more likely to be underweight (19.6% versus 10.0%, p = 0.03) or stunted (39.1% versus 30.6%, p = 0.04) but did not report poorer physical or psychological ill-health. Where maternal data were available, reported mothers of 61/62 HIV-positive children were deceased or HIV-positive. Risk factors for other sources of infection were not associated with child HIV infection, including blood transfusion, vaccinations, caring for a sick relative, and sexual abuse. The observed flat age-pattern of HIV prevalence was consistent with UNAIDS estimates which assumes perinatal mother-to-child transmission, although modelled prevalence was higher than observed prevalence. Only 19/73 HIV-positive children (26.0%) were diagnosed, but, of these, 17 were on antiretroviral therapy. CONCLUSIONS: Childhood HIV infection likely arises predominantly from mother-to-child transmission and is associated with poorer physical development. Overall antiretroviral therapy uptake was low, with the primary barrier to treatment appearing to be lack of diagnosis.

The contribution of schools to supporting the well being of children affected by HIV in eastern Zimbabwe.

OBJECTIVES: Schools are often cited as a source of support for orphans and children affected by HIV/AIDS in populations experiencing generalized HIV epidemics and severe poverty. Here we investigate the success of schools at including and supporting the well being of vulnerable children in rural Zimbabwe. DESIGN: Data from a cross-sectional household survey of 4577 children (aged 6-17 years), conducted between 2009 and 2011, were linked to data on the characteristics of 28 primary schools and 18 secondary schools from a parallel monitoring and evaluation facility survey. METHODS: We construct two measures of school quality (one general and one HIV-specific) and use multivariable regression to test whether these were associated with improved educational outcomes and well being for vulnerable children. RESULTS: School quality was not associated with primary or secondary school attendance, but was associated with children's being in the correct grade for age [adjusted odds ratio 2.0, 95% confidence interval (CI) 1.2-3.5, P = 0.01]. General and HIV-specific school quality had significant positive effects on well being in the primary school-age children (coefficient 5.1, 95% CI 2.4-7.7, P < 0.01 and coefficient 3.0, 95% CI 0.4-5.6, P = 0.02, respectively), but not in the secondary school-age children (P > 0.2). There was no evidence that school quality provided an additional benefit to the well being of vulnerable children. Community HIV prevalence was negatively associated with well being in the secondary school-age children (coefficient -0.7, 95% CI -1.3 to -0.1, P = 0.03). CONCLUSIONS: General and HIV-specific school quality may enhance the well being of primary school-age children in eastern Zimbabwe. Local community context also plays an important role in child well being.

Community-derived research dissemination strategies in an Inuit community.

OBJECTIVES: To determine how residents of the Inuit community of Nain, Nunatsiavut, Canada would like research results disseminated to their community. STUDY DESIGN: Qualitative study using focus groups and key informant interviews. METHODS: As part of a larger study on food safety, one focus group was conducted with hunters (n=7) and a second with members of the general community (n=7) to determine research dissemination strategies previously used in the community, and to obtain recommendations for effective and appropriate strategies for future use. One-on-one key informant interviews were also conducted with Nain community members (n=5) selected for their insights on the study themes. Informants included a teacher, a nurse, a community elder, and one official from each of the Nain and Nunatsiavut governments. Data from focus groups and key informant interviews were combined and analysed using thematic analysis. RESULTS: Open houses were identified as the preferred method to present research results to the community. Presentation methods should be interactive, visual and presented in both English and Inuktitut. Research dissemination efforts should be timely and involve both the researcher and a local official or community member to give the results additional validity and relevance. If possible, involving youth in the presentations will increase the impact of the message. CONCLUSION: Preferred information dissemination techniques in this Inuit community echo successful techniques from research conducted in Aboriginal communities. Future knowledge translation efforts in Inuit communities should consider involving youth in presentations due to their influential nature within the community.