This systematic scoping review synthesizes evidence on lymphatic filariasis, onchocerciasis, and mansonellosis across Latin American populations from 1946 to 2025. The scope includes adults in endemic communities and children in transmission assessment surveys, evaluating mass drug administration (MDA) against pre-MDA baselines or different diagnostic methods.
Key findings illustrate substantial reductions in infection markers. In the Dominican Republic's La Ciénaga focus, circulating filarial antigen (CFA) positivity declined from 10.7% in 2002 to 0% in 2014. Similarly, Onchocerca volvulus skin microfilarial positivity in Guatemala's San Vicente Pacaya focus was 31% in 1976–1977, while OV16 IgG4 seropositivity in Guatemala's Huehuetenango reached 0% in children in 2007–2008. In Ecuador's Esmeraldas focus, vector infectivity (O-150 PCR) was 0% by 2008, and OV16 IgG4 seropositivity was 0% in children and adolescents in 2001–2008.
The review also reports on Mansonella ozzardi, with positivity at ~40% by whole-blood loop-mediated isothermal amplification (LAMP) and 12.7% by blood smear microscopy in Colombia's Amazonas Department in 2021–2023. In the Brazilian Amazon, positivity was 6.3% in Tefé Riverine communities and 13.6% overall in Tefé municipality surveys in 2012, compared to 43.4% in another Amazonian cohort in 2009–2010.
Authors note significant limitations, including the use of different diagnostic methods such as microscopy, antigen tests, serology, and molecular assays that vary in sensitivity and specificity. Sampling differences between adults and children, combined with highly focal transmission, mean prevalence can vary substantially even between nearby communities. Safety data and adverse events were not reported.
View Original Abstract ↓
Filarial infections—lymphatic filariasis, onchocerciasis, and mansonellosis—persist as neglected tropical diseases in Latin America despite control efforts. Comparing filarial trends over time is challenging because studies use different diagnostic methods such as microscopy, antigen tests, serology, and molecular assays that vary in sensitivity, specificity, and whether they detect active infection or past exposure, while also sampling different populations such as adults in endemic communities versus children in transmission assessment surveys. Transmission is also highly focal, so prevalence can vary substantially even between nearby communities. We searched MEDLINE, Embase, CENTRAL, LILACS, Web of Science, SciELO, and Global Health (1946–2025) to summarize reported epidemiology and burden of filarial infections in Latin America before and after mass drug administration (MDA) scale-up. For lymphatic filariasis, the Dominican Republic’s La Ciénaga focus (Santo Domingo) declined from 10.7% circulating filarial antigen (CFA) positivity in 2002 to 0% CFA-positive children (aged 6–7 years) in a 2014 transmission assessment survey (TAS) using the immunochromatographic test after three MDA rounds (2004–2006). In Haiti, Nippes Department surveys detected 1.5% CFA positivity in 2019, while pooled TAS results across 54 implementation units during 2017–2022 found 0.19% CFA positivity among children aged 6–7 years. For onchocerciasis, Guatemala’s San Vicente Pacaya focus reported 31% Onchocerca volvulus skin microfilarial positivity by skin-snip microscopy in 1976–1977, whereas Huehuetenango reported 0% OV16 IgG4 seropositivity in children in 2007–2008. In Ecuador’s Esmeraldas focus (Cayapas River area), early surveys documented 83% infection by skin-snip microscopy. In comparison, post-MDA monitoring showed 0% vector infectivity (O-150 PCR) by 2008 and 0% OV16 IgG4 seropositivity in children and adolescents (2001–2008), supporting MDA cessation in 2009. For Mansonellosis, prevalence in the Brazilian Amazon ranged from 6.3% in Tefé Riverine communities to 13.6% overall in Tefé municipality surveys (both in 2012; thick blood smear microscopy), and reached 43.4% in another Amazonian cohort (2009–2010; blood microfilariae detection by microscopy). In Colombia’s Amazonas Department (Leticia/Puerto Nariño), whole-blood loop-mediated isothermal amplification (LAMP) detected ~40% Mansonella ozzardi positivity in 2021–2023, compared with 12.7% by blood smear microscopy in the same study, illustrating diagnostic sensitivity differences. The reviewed data show clear reductions in lymphatic filariasis and onchocerciasis after MDA scale-up, whereas mansonellosis remains common in several Amazonian regions. Reported prevalence varies across studies due to differences in diagnostic approaches, surveyed populations, and localized transmission patterns.
