Assessment of lymphatic filariasis prior to re-starting mass drug administration campaigns in coastal Kenya

Abstract

BackgroundLymphatic filariasis (LF) is a debilitating disease associated with extensive disfigurement and is one of a diverse group of diseases referred to as neglected tropical diseases (NTDs) which mainly occur among the poorest populations. In line with global recommendations to eliminate LF, Kenya launched its LF elimination programme in 2002 with the aim to implement annual mass drug administration (MDA) in order to interrupt LF transmission. However, the programme faced financial and administrative challenges over the years such that sustained annual MDA was not possible. Recently, there has been renewed interest to eliminate LF and the Kenyan Ministry of Health, through support from World Health Organization (WHO), restarted annual MDA in 2015. The objective of this study was to evaluate the current status of LF infection in the endemic coastal region of Kenya before MDA campaigns were restarted.ResultsTen sentinel sites in Kwale, Kilifi, Tana River, Lamu, and Taita-Taveta counties in coastal Kenya were selected for participation in a cross-sectional survey of LF infection prevalence. At least 300 individuals in each sentinel village were sampled through random house-to-house visits. During the day, the point-of-care immunochromatographic test (ICT) was used to detect the presence of Wuchereria bancrofti circulating filarial antigen in finger prick blood samples collected from residents of the selected sentinel villages. Those individuals who tested positive with the ICT test were requested to provide a night-time blood sample for microfilariae (MF) examination. The overall prevalence of filarial antigenaemia was 1.3% (95% CI: 0.9–1.8%). Ndau Island in Lamu County had the highest prevalence (6.3%; 95% CI: 4.1–9.7%), whereas sites in Kilifi and Kwale counties had prevalences < 1.7%. Mean microfilarial density was also higher in Ndau Island (234 MF/ml) compared to sentinel sites in Kwale and Kilifi counties (< 25 MF/ml). No LF infection was detected in Tana River and Taita-Taveta counties. Overall, more than 88% of the study participants reported to have used a bed net the previous night.ConclusionsPrevalence of LF infection is generally very low in coastal Kenya, but there remain areas that require further rounds of MDA if the disease is to be eliminated as a public health problem in line with the ongoing global elimination efforts. However, areas where there was no evidence of LF transmission should be considered for WHO-recommended transmission assessment surveys in view of stopping MDA.

Molecular Characterization and Phylogenetic analysis ofWuchereria bancroftiin human blood samples from Malindi and Tana River Delta, endemic regions in Kenya

“…There was a great divergence observed within Malindi population (0.95) compared to that of Tana River Delta (0.4), this can be attributed to the long period Malindi has been on MDA (from 2003) to Tana River (from 2011) . By 2015 Malindi had received a total of 5 rounds while Tana River had received only 1 rounds of MDA [12]. Although a combined single dose of Albendazole and Diethylcarbamizine or Ivermectin has been used by Lymphatic filariasis control programmes effectively, reliance on these drugs only is highly vulnerable to emergence and spread of drug resistance.…”

“…A significant decline of W. bancrofti prevalence in Kenya has been noted [10], [11], [12] following MDA implementation and vector control programmes in Kenya. It is however evidenced MDA may lead that to genetic variability or resistance strains of W. bancrofti and this may result to resurgence of disease after elimination or increased prevalence.…”

“…The MDA treatment in Kenya is based on combined single-dose for annual mass treatment in 2003, the Programme scaled up to Malindi and Kwale districts. Two more rounds of MDA were conducted in these districts in 2005, 2008, 2011 and then 2015 [10], [11], [12]. The treatment has however not been consistent with WHO recommendations of annual MDA for 4-6 years which may result in resurgence of transmission and development of genetic variations of the circulating parasites.…”

Multiplex serologic testing within a cross-sectional lymphatic filariasis sentinel site survey in coastal Kenya reveals community-level differences in IgG antibody responses to parasitic diseases and vaccines

“…The DBS samples used in this study were collected during a cross-sectional LF survey conducted in October 2015 in ten sentinel sites located across the coastal region in Taita-Taveta, Kwale, Kilifi, Tana River and Lamu counties as previously described [17]. Briefly, 300 persons aged 2 years or more in each sentinel site were targeted for the LF survey as recommended in the WHO guidelines [11].…”

“…Substantial progress has been made towards elimination of LF, with Togo being the first country in sub-Saharan Africa to be recognized by WHO for eliminating the disease as a public health problem [14,15]. The Kenyan Ministry of Health launched an LF elimination program in 2002, but the program did not sustain MDA campaigns annually as per GPELF recommendations [16,17]. In 2015, the Ministry of Health successfully appealed to World Health Organization Regional Office for Africa (WHO-AFRO) and other partners for support to re-establish annual MDA campaigns.…”