RESUMO
Emerging infectious diseases are an increasingly important threat to wildlife conservation, with amphibian chytridiomycosis, caused by Batrachochytrium dendrobatidis, the disease most commonly associated with species declines and extinctions. However, some amphibians can be infected with B. dendrobatidis in the absence of disease and can act as reservoirs of the pathogen. We surveyed robber frogs (Eleutherodactylus spp.), potential B. dendrobatidis reservoir species, at three sites on Montserrat, 2011-2013, and on Dominica in 2014, to identify seasonal patterns in B. dendrobatidis infection prevalence and load (B. dendrobatidis genomic equivalents). On Montserrat there was significant seasonality in B. dendrobatidis prevalence and B. dendrobatidis load, both of which were correlated with temperature but not rainfall. B. dendrobatidis prevalence reached 35% in the cooler, drier months but was repeatedly undetectable during the warmer, wetter months. Also, B. dendrobatidis prevalence significantly decreased from 53.2% when the pathogen emerged on Montserrat in 2009 to a maximum 34.8% by 2011, after which it remained stable. On Dominica, where B. dendrobatidis emerged seven years prior to Montserrat, the same seasonal pattern was recorded but at lower prevalence, possibly indicating long-term decline. Understanding the dynamics of disease threats such as chytridiomycosis is key to planning conservation measures. For example, reintroductions of chytridiomycosis-threatened species could be timed to coincide with periods of low B. dendrobatidis infection risk, increasing potential for reintroduction success.
RESUMO
BACKGROUND: While progress has been made in the elimination of lymphatic filariasis, challenges that call for innovative approaches remain. Program challenges are increasingly observed in 'hard-to-reach' populations: urban dwellers, migrant populations, those living in insecurity, children who are out of school and areas where infrastructure is weak and education levels are low. 'Business-as-usual' approaches are unlikely to work. Tailored solutions are needed if elimination goals are to be reached. This article focuses on mass drug administrations (MDAs) in urban settings. METHODS: We selected the urban poor area of Santo Domingo, Dominican Republic. With three rounds of MDA and with good coverage, elimination was achieved. We wanted to understand contributing factors to achieving good coverage. A qualitative study analyzed context, barriers and facilitators using a predefined framework based on review of the literature. RESULTS: Results show that barriers commonly reported in urban settings were present (population density, lack of organization in household layout, population mobility, violence, shortage of human resources and challenges in monitoring treatment coverage). Tactics used included strong visibility in the community leading to high levels of awareness, the use of laminated photo sheets during house-to-house visits and a 1:4 supervision strategy. The importance of working through community leadership structures and building relationships with the community was evident. DISCUSSION: The approach developed here has applications for large-scale treatment programs for lymphatic filariasis and other diseases in urban settings.