Elimination of lymphatic filariasis in west African urban areas: is implementation of mass drug administration necessary?

Abstract

Lymphatic filariasis in Africa is caused by the parasite Wuchereria bancrofti and remains a major cause of morbidity and disability in 74 countries globally. A key strategy of the Global Programme for the Elimination of Lymphatic Filariasis, which has a target elimination date of 2020, is the treatment of entire endemic communities through mass drug administration of albendazole in combination with either ivermectin or diethylcarbamazine. Although the strategy of mass drug administration in combination with other interventions, such as vector control, has led to elimination of the infection and its transmission in many rural communities, urban areas in west Africa present specific challenges to achieving the 2020 targets. In this Personal View, we examine these challenges and the relevance of mass drug administration in urban areas, exploring the rationale for a reassessment of policy in these settings. The community-based mass treatment approach is best suited to rural areas, is challenging and costly in urban areas, and cannot easily achieve the 65% consistent coverage required for elimination of transmission. In our view, the implementation of mass drug administration might not be essential to interrupt transmission of lymphatic filariasis in urban areas in west Africa. Evidence shows that transmission levels are low and that effective mass drug distribution is difficult to implement, with assessments suggesting that specific control measures against filariasis in such dynamic settings is not an effective use of limited resources. Instead, we recommend that individuals who have clinical disease or who test positive for W bancrofti infection in surveillance activities should be offered antifilarial drugs through a passive surveillance approach, as well as morbidity management for their needs. We also recommend that more precise studies are done, so that mass drug administration in urban areas is considered if sustainable transmission is found to be ongoing. Otherwise, the limited resources should be directed towards other elements of the lymphatic filariasis programme.

Methods for the generation of heritable germline mutations in the disease vector Culex quinquefasciatus using clustered regularly interspaced short palindrome repeats‐associated protein 9

“…Current estimates indicate that despite remarkable mass drug administration (MDA) programs, millions of people are currently infected with lymphatic filariasis, which is considered one of the leading global causes of disability (Gyapong et al, 2018). Furthermore, there are many areas of the world where MDA is not expected to eradicate this disease, so greater mosquito control efforts may be needed to accomplish this goal (Koudou et al, 2018). Moreover, C. quinquefasciatus has established itself as the dominant vector of avian malaria on many islands, and in some instances caused the extinction of many rare bird species (LaPointe et al, 2012).…”

Low transmission of Wuchereria bancrofti in cross-border districts of Côte d’Ivoire: A great step towards lymphatic filariasis elimination in West Africa

“…In the same line, Rao et al [38] recorded persistent W. Bancrofti infection in Sri Lanka that has low-level persistence of LF following multiple rounds of MDA in American Samoa. Recent empirical evidence has demonstrated that EPHP does not always lead to elimination of transmission (EOT) [2,39]. Residual infection remaining after MDA cessation can lead to resurgence and reintroduction [40,41], with longterm persistence dependent on a range of factors [35], including the presence of W. bancroftiinfected mosquitoes [2,39].…”

“…Recent empirical evidence has demonstrated that EPHP does not always lead to elimination of transmission (EOT) [2,39]. Residual infection remaining after MDA cessation can lead to resurgence and reintroduction [40,41], with longterm persistence dependent on a range of factors [35], including the presence of W. bancroftiinfected mosquitoes [2,39]. Importantly, we detected W. bancrofti mf in Odienné, even if at low prevalence (0.16%) and low microfilaremia (32.0 Mf/mL).…”

“…A tripledrug therapy may be recommended to accelerate the EPHP for FL [3,7,42,43]. Moreover, LLINs could be integrated to MDA to accelerate the progress of EPHP and the reduction of LF infection in this health district [2,39]. Indeed, Jones et al [44] reported that 12 rounds of MDA complemented with vector control through the use of LLINs resulted in a marked reduction in W. bancrofti CFA in young school children in Tanzania where mosquitoes were transmitting LF parasites.…”

Methods for the generation of heritable germline mutations in the disease vector Culex quinquefasciatus using CRISPR/Cas9

“…Current estimates indicate that despite remarkable mass drug administration (MDA) programs, millions of people are currently infected with lymphatic filariasis, which is considered to be one of the leading global causes of disability (Gyapong et al 2018). Furthermore, there are many areas of the world where MDA is not expected to eradicate this disease, but mosquito control could be the key to eliminating this disease (Koudou et al 2018). Moreover, Cx.…”