Moustiquaires imprégnées d'insecticides longue durée et tests diagnostiques rapides du paludisme : implication dans le contrôle du paludisme au centre de la Côte d'Ivoire

Malaria is a vector-borne disease that primarily affects rural dwellers in the tropics and subtropics. In areas of high transmission, the highest mortality and morbidity rates are found in rural settings with seasonal variations that might be governed by irrigated rice farming. The use of long-lasting insecticidal nets (LLINs), adequate case management facilitated by rapid diagnostic tests (RDTs) and prompt treatment with artemisinin-based combination therapy are key tools for malaria control. The effectiveness of these control measures might be further enhanced by the implementation of communication strategies aiming at increasing population LLINs ownership. We evaluated the effect of routine LLINs monitoring and active surveillance of Plasmodium falciparum infection using RDTs and treatment administration at the community level on malaria transmission, infection and morbidity. Additionally, the acceptability of RDTs for malaria was investigated.
Goal and specific objectives
This PhD pursued four specific objectives: (i) to evaluate the effect of LLINs on species composition and abundance of wild Culicidae; (ii) to evaluate the impact of LLINs routine monitoring on transmission indicators; (iii) to evaluate the impact of LLINs routine monitoring associated with the detection of malaria cases using RDTs on malaria prevalence and morbidity; and (iv) to determine socio-economic factors impacting the use of LLINs and identify attitudes and beliefs affecting RDTs acceptability.
Methods
The study was carried out between July 2009 and May 2012 in three villages (N’dakonankro, Yoho and Bozi) in central Côte d’Ivoire. In Bozi, 150 households were given LLINs free of charge. Five entomological surveys (collection of larvae and adult mosquitoes) were conducted: two before and three after free distribution of LLINs at 3-month intervals. Three parasitological surveys (examination of Giemsa-stained thick and thin blood films and RDTs) were carried out: one prior to and two after free LLIN distribution at 6-month intervals. Additionally, two socio-cultural and economic surveys using a questionnaire were carried out.
Results
The results of our study showed that longitudinal monitoring and implementing a locally adapted communication strategy at the household level were associated with reduced malaria transmission and lower P. falciparum prevalence rates. The adherence of the population to properly use LLINs increased net utilization to very high levels (95-100%). While a rapid decrease in malaria transmission in Bozi was observed, declines in malaria incidence and prevalence required longer time. Our results highlight the scope and limitations of implementing local malaria control measures. A significant relationship between people’s educational attainment, socio-economic position and nets ownership have been observed. In addition social representations about malaria, blood and blood-related diseases preventing an efficient introduction and routine use of RDTs have been found.
Conclusions
In central Côte d’Ivoire, scaling up and sustained use of LLINs should be carefully monitored at the household level. Moreover, the integration of larval control holds promise to significantly reducing malaria transmission. Specific health messages tailored to the local context should be used to raise awareness about the use of RDTs for malaria. Remaining challenges (e.g. strategies adapted to the local conditions of information, education and communication, and diagnosis and prevention) must be overcome for integrated control and eventual local elimination of malaria.