Research Article: Mapping of Bancroftian Filariasis in Cameroon: Prospects for Elimination

Date Published: September 9, 2015

Publisher: Public Library of Science

Author(s): Hugues C. Nana-Djeunga, Jules B. Tchatchueng-Mbougua, Jean Bopda, Steve Mbickmen-Tchana, Nathalie Elong-Kana, Etienne Nnomzo’o, Julie Akame, Ann Tarini, Yaobi Zhang, Flobert Njiokou, Joseph Kamgno, John Owusu Gyapong.

Abstract: BackgroundLymphatic filariasis (LF) is one of the most debilitating neglected tropical diseases (NTDs). It still presents as an important public health problem in many countries in the tropics. In Cameroon, where many NTDs are endemic, only scant data describing the situation regarding LF epidemiology was available. The aim of this study was to describe the current situation regarding LF infection in Cameroon, and to map this infection and accurately delineate areas where mass drug administration (MDA) was required.MethodologyThe endemicity status and distribution of LF was assessed in eight of the ten Regions of Cameroon by a rapid-format card test for detection of W. bancrofti antigen (immunochromatographic test, ICT). The baseline data required to monitor the effectiveness of MDA was collected by assessing microfilariaemia in nocturnal calibrated thick blood smears in sentinel sites selected in the health districts where ICT positivity rate was ≥ 1%.Principal findingsAmong the 120 health districts visited in the eight Regions during ICT survey, 106 (88.3%) were found to be endemic for LF (i.e. had ICT positivity rate ≥ 1%), with infection rate from 1.0% (95% CI: 0.2–5.5) to 20.0% (95% CI: 10–30). The overall infection rate during the night blood survey was 0.11% (95% CI: 0.08–0.16) in 11 health districts out of the 106 surveyed; the arithmetic mean for microfilaria density was 1.19 mf/ml (95% CI: 0.13–2.26) for the total population examined.Conclusion/significanceICT card test results showed that LF was endemic in all the Regions and in about 90% of the health districts surveyed. All of these health districts qualified for MDA (i.e. ICT positivity rate ≥ 1%). Microfilariaemia data collected as part of this study provided the national program with baseline data (sentinel sites) necessary to measure the impact of MDA on the endemicity level and transmission of LF important for the 2020 deadline for global elimination.

Partial Text: Lymphatic filariasis (LF) is a parasitic disease caused by three species of thread-like nematode worms—Wuchereria bancrofti, Brugia malayi and Brugia timori—known as filariae. Of these three parasite species, W. bancrofti accounts for nearly 90 percent of LF infections worldwide. Brugia malayi is prevalent only in some parts of South and Southeast Asia, and B. timori is found only in Indonesia [1]. Currently, nearly 1.4 billion people in 73 countries worldwide are threatened by LF, with an estimated number of 120 million people infected, and about 40 million disfigured and incapacitated by the disease [2]. LF is a vector-borne disease; several species of Culex, Anopheles, Aedes, and Mansonia mosquitoes are known to be involved in its transmission.

The present study was carried out to map the distribution of LF in Cameroon and provide the national program with baseline data for the assessment of the impact of treatments on the level of endemicity and transmission of the infection.



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