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| Background: Past case reports have indicated that lymphatic filariasis (LF) occurs in Zambia, but knowledge about its
geographical distribution and prevalence pattern, and the underlying potential environmental drivers, has been limited. As
a background for planning and implementation of control, a country-wide mapping survey was undertaken between 2003
and 2011. Here the mapping activities are outlined, the findings across the numerous survey sites are presented, and the
ecological requirements of the LF distribution are explored.
Methodology/Principal findings: Approximately 10,000 adult volunteers from 108 geo-referenced survey sites across
Zambia were examined for circulating filarial antigens (CFA) with rapid format ICT cards, and a map indicating the
distribution of CFA prevalences in Zambia was prepared. 78% of survey sites had CFA positive cases, with prevalences
ranging between 1% and 54%. Most positive survey sites had low prevalence, but six foci with more than 15% prevalence
were identified. The observed geographical variation in prevalence pattern was examined in more detail using a species
distribution modeling approach to explore environmental requirements for parasite presence, and to predict potential
suitable habitats over unsurveyed areas. Of note, areas associated with human modification of the landscape appeared to
play an important role for the general presence of LF, whereas temperature (measured as averaged seasonal land surface
temperature) seemed to be an important determinant of medium-high prevalence levels.
Conclusions/significance: LF was found to be surprisingly widespread in Zambia, although in most places with low
prevalence. The produced maps and the identified environmental correlates of LF infection will provide useful guidance for
planning and start-up of geographically targeted and cost-effective LF control in Zambia. | |
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