Spatial predictive risk mapping of lymphatic filariasis residual hotspots in American Samoa using demographic and environmental factors.

BACKGROUND: American Samoa successfully completed seven rounds of mass drug administration (MDA) for lymphatic filariasis (LF) from 2000-2006. The territory passed the school-based transmission assessment surveys in 2011 and 2015 but failed in 2016. One of the key challenges after the implementation of MDA is the identification of any residual hotspots of transmission. METHOD: Based on data collected in a 2016 community survey in persons aged ≥8 years, Bayesian geostatistical models were developed for LF antigen (Ag), and Wb123, Bm14, Bm33 antibodies (Abs) to predict spatial variation in infection markers using demographic and environmental factors (including land cover, elevation, rainfall, distance to the coastline and distance to streams). RESULTS: In the Ag model, females had a 26.8% (95% CrI: 11.0-39.8%) lower risk of being Ag-positive than males. There was a 2.4% (95% CrI: 1.8-3.0%) increase in the odds of Ag positivity for every year of age. Also, the odds of Ag-positivity increased by 0.4% (95% CrI: 0.1-0.7%) for each 1% increase in tree cover. The models for Wb123, Bm14 and Bm33 Abs showed similar significant associations as the Ag model for sex, age and tree coverage. After accounting for the effect of covariates, the radii of the clusters were larger for Bm14 and Bm33 Abs compared to Ag and Wb123 Ab. The predictive maps showed that Ab-positivity was more widespread across the territory, while Ag-positivity was more confined to villages in the north-west of the main island. CONCLUSION: The findings may facilitate more specific targeting of post-MDA surveillance activities by prioritising those areas at higher risk of ongoing transmission.

Young adults HIV-1 infected by vertical transmission in southern Brazil - Clinical, demographic, and virological features.

Combination antiretroviral therapy promotes longer life expectancy, making it possible for perinatally HIV-infected patients to achieve adulthood. Past therapy was not always optimized, suggesting that virological and host features may also play a role in survival. The aim of this study is to describe characteristics of HIV disease progression associated with virological features in adolescents perinatally that were HIV infected. A case series was conducted including 81 patients that were in follow-up at Hospital de Clínicas/Universidade Federal do Paraná, Curitiba, Brazil. Venous blood was collected to conduct tropism and viral subtype assays. The median age was 19 years old (interquartile range 18-21), and a majority of patients were female (54.3%). Viral subtype was obtained for 66 (82%) patients, and subtypes B and C were found in 34% and 59%, respectively. Tropism assay was conducted in 55 (67%) patients: 71% were R5 and 29% X4. Distribution of viral tropism and subtype shows a significant association of subtype C with R5 tropism. Subtype C is more prevalent in southern Brazil and also in the population infected with HIV by vertical transmission. Both R5 tropism and subtype C are associated with slower progression to AIDS. The survival of these patients may be related to virological features present in a benign pattern of disease progression.