Objectives To quantify the burden of HIV, syphilis and schistosome infection and associated risk factors among adults living in seven fishing communities of Lake Victoria in northwest Tanzania... Show moreObjectives To quantify the burden of HIV, syphilis and schistosome infection and associated risk factors among adults living in seven fishing communities of Lake Victoria in northwest Tanzania.Methods Cross-sectional study conducted between 2015 and 2016 in the selected communities. In each community, we randomly selected a sample of adults from the general population and from three putative risk groups including the following: (i) fishermen, (ii) fish processors and traders, and (iii) women working in the recreational facilities. Participants were interviewed to obtain information about potential risk factors, and venous blood was collected for detection of HIV, syphilis and schistosome infections. We used logistic regression models to quantify the associations between potential risk factors and HIV, and also between schistosome infection and HIV.Results We enrolled 1128 people from selected fishing communities. The overall prevalence of HIV, syphilis and schistosome infection was 14.2%, 15.6% and 83.1%, respectively. Female recreational facility workers had the highest prevalence of HIV (30.4%) and syphilis (24%). The odds of being HIV infected were generally higher in all age categories. Transactional sex was commonly reported and especially receiving gifts for sex was found to be strongly associated with HIV (adjusted OR = 2.50; 95% CI: 1.44-4.34, P = 0.008). Confirmed serological syphilis was associated with increased odds of having HIV infection. HIV was not associated with schistosome infection in a combined dataset and when we examined this separately for men and women alone.Conclusions We observed a high burden of HIV, syphilis and schistosome infections in the fishing communities. Targeted efforts to treat and control infections have the potential to improve health among their residents. Show less
Background Current World Health Organization (WHO) guidelines recommend annual mass drug administration using praziquantel in areas with high schistosome endemicity. Yet little is known about... Show moreBackground Current World Health Organization (WHO) guidelines recommend annual mass drug administration using praziquantel in areas with high schistosome endemicity. Yet little is known about incidence and reinfection rates after treatment in women with frequent exposure to schistosomes. We sought to quantify response to anti-schistosome treatment and incident S. mansoni infections in a cohort of rural women living in a schistosome-endemic area of northwest Tanzania. Methods and principal findings We enrolled women with and without S. mansoni infection into a 12-month longitudinal cohort. Every 3 months, women were tested for schistosome infection using microscopic examinations for ova on filtered urine, Kato Katz slides, and serum Circulating Anodic Antigen (CAA). Those with schistosome infection received treatment with praziquantel 40 mg/kg according to the standard of care. We studied 35 women who were S. mansoni positive by stool microscopy and 46 women without schistosome infection who returned for at least one follow-up. Of the women who were initially infected, 14 (40%) were schistosome-positive at a follow-up visit. Four women developed incident infections, for a cumulative incidence of 8.7% and incidence rate of 0.99 per 100 person-months throughout the year among initially uninfected women. Only 3 women were egg-positive at any follow-up. Women with persistent, recurrent, or incident infection during the study period were significantly younger (p = 0.032) and had fewer children than women who remained uninfected or those who cleared the infection and did not experience recurrence (p = 0.003). Having fewer children remained significant after controlling for age (p = 0.023). There was no difference in initial intensity of infection by CAA or stool egg count, HIV status, or socioeconomic status. Although most water contact behaviors were comparable between the two groups, women with recurrent or incident schistosome infections were significantly more likely to have recently swum in the lake (p = 0.023). Conclusions Our data suggests that annual praziquantel treatment reduces intensity of schistosome infections but is insufficient in providing stable parasite eradication in over a third of women in endemic communities. Furthermore, microscopy lacks adequate sensitivity to evaluate efficacy of treatment in this population. Our work demonstrates that further investigation into treatment efficacy and reinfection rates is warranted and suggests that increased frequency of praziquantel treatment is needed to improve cure rates in high-risk populations.Author summary Schistosomiasis is a parasitic infection transmitted through contaminated water that primarily affects the gastrointestinal and urogenital tracts. Previous studies in Tanzania have shown that adult women infected with schistosomes also have a higher risk of contracting HIV. Although it is recommended that people living in areas where they are exposed to schistosomes be treated with praziquantel once a year, the rate of new infections or reinfection after treatment in adult women is not known. We followed a group of schistosome-infected women and an uninfected control group for 12 months. They were tested for schistosomes every 3 months, and treated with praziquantel if they were infected. Over 40% of the women tested positive for schistosome infection at some point during the follow-up period, and the majority of them were from the group that was infected at the beginning of the study. These women may not have fully cleared the infection after one treatment, or they may be more susceptible to reinfection due to variations in their immune systems. Further studies are recommended to investigate whether a higher frequency of treatment is needed to control schistosome infection in adult women, especially given that reducing schistosome infection may help to reduce HIV risk in populations similar to ours. Show less
