Dorothée Kinde Gazard

Malaria control is heavily reliant on insecticides, especially pyrethroids. Resistance of mosquitoes to insecticides may threaten the effectiveness of insecticide-based vector control and lead to a resurgence of malaria in Africa. In 21 villages in Southern Benin with high levels of insecticide resistance, the resistance status of local vectors was measured at the same time as the prevalence of malaria infection in resident children. Children who used LLINs had lower levels of malaria infection [odds ratio = 0.76 (95% CI 0.59, 0.98, p = 0.033)]. There was no evidence that the effectiveness of nets was different in high and low resistance locations (p = 0.513). There was no association between village level resistance and village level malaria prevalence (p = 0.999). LLINs continue to offer individual protection against malaria infection in an area of high resistance. Insecticide resistance is not a reason to stop efforts to increase coverage of LLINs in Africa.

Artemether/lumefantrine (Coartem®) has been used as a treatment for uncomplicated Plasmodium falciparum infection since 2004 in Benin. This open-label, non-randomized study evaluated efficacy of artemether–lumefantrine (AL) in treatment of uncomplicated falciparum malaria in children aged 6–59 months in two malaria transmission sites in northwest Benin. A 42-day therapeutic efficacy study was conducted between August and November 2014, in accordance with 2009 WHO guidelines. One-hundred and twenty-three children, aged 6 months to 5 years, with uncomplicated falciparum malaria were recruited into the study. The primary endpoint was parasitological cure on day 28 and day 42 while the secondary endpoints included: parasite and fever clearance, improvement in haemoglobin levels. Outcomes were classified as early treatment failure (ETF), late clinical failure, late parasitological failure, and adequate clinical and parasitological response (ACPR). Before PCR correction, ACPR rates were 87 % (95 % CI 76.0–94.7) and 75.6 %, respectively (95 % CI 67.0–82.9) on day 28 and day 42. In each study site, ACPR rates were 78.3 % in Djougou and 73 % in Cobly on day 42. There was no ETF and after PCR correction ACPR was 100 % in study population. All treatment failures were shown to be due to new infections. Fever was significantly cleared in 24 h and approximately 90 % of parasites where cleared on day 1 and almost all parasites were cleared on day 2. Haemoglobin concentration showed a slight increase with parasitic clearance. AL remains an efficacious drug for the treatment of uncomplicated falciparum malaria in Benin, although higher rates of re-infection remain a concern. Surveillance needs to be continued to detect future changes in parasite sensitivity to artemisinin-based combination therapy.

In Benin, very few studies have been done on the genetics of Plasmodium falciparum and the resistance markers of anti-malarial drugs, while malaria treatment policy changed in 2004. Chloroquine (CQ) and sulphadoxine pyrimethamine (SP) have been removed and replaced by artemisinin-combination therapy (ACT). The objective of this study was to determine the genetic diversity of P. falciparum and the prevalence of P. falciparum molecular markers that are associated with resistance to CQ and SP in northern Benin seven years after the new policy was instituted.

In Benin, the National Malaria Control Programme (NMCP) changed the policy of malaria treatment in 2004 following increasing of failure rate of treatment with chloroquine (CQ) and sulphadoxine-pyrimethamine (SP). The objective of this study was to determinate the prevalence of Plasmodium falciparum molecular markers that are associated with resistance to CQ and SP in Benin seven years after the new policy was instituted.

La présente étude vise à évaluer les résultats du projet d’appui à la lutte contre le paludisme dans les départements du Mono et du Couffo au Bénin sur l’utilisation des moustiquaires imprégnées d’insecticide (MII) par les enfants de moins de cinq ans et les femmes enceintes et sur la couverture par le traitement présomptif intermittent (TPI) le taux de couverture par le traitement préventif intermittent (TPI) à la Sulfadoxine-Pyriméthamine (SP). Cette évaluation est faite à partir de deux enquêtes ménages. La première avant le démarrage et la seconde réalisée après 15 mois de mise en oeuvre des interventions. La disponibilité des ménages en MII ainsi que leur utilisation par les femmes enceintes et les enfants de moins de cinq ans sont passés respectivement de 8, 5 et 4 % en 2005 à 24, 31 et 16 % en 2006. Le pourcentage de femmes enceintes sous TPI à la sulfadoxine-pyriméthamine (SP) est de 10 % alors que 21 % des femmes enceintes ont reçu au moins une dose de SP. Des stratégies efficaces de communication pour un changement de comportements pourraient améliorer les résultats, ainsi qu’un renforcement des capacités pour la gestion des stocks de médicaments dans les centres de santé. This study aims to evaluate the results of the Project to Support the Fight against Malaria in the departments of Mono and Couffo in Benin on insecticide-treated nets (ITNs) use by children under 5 years and pregnant women and the coverage by Intermittent Preventive Treatment (IPT) with Sulfadoxin-Pyrimethamin (SP). This assessment is made from two household surveys. The first at the start up and the second after fifteen months of implementation. The availability of ITN in households and their use by pregnant women and children under 5 years have increased respectively from 8, 5 and 4% in 2005 to 24, 31 and 16 % in 2006. The percentage of pregnant women under IPT with sulfadoxine-pyrimethamine (SP) is 10% while 21% of pregnant women received at least one dose of SP. The availability of ITN in households and their use by children under 5 years and the prevention of malaria during pregnancy remains a concern in these health areas. The promotion of long lasting insecticide treated nets with effective communication strategies for behavior change could improve the results. Research on causes of poor compliance of IPT should be emphasized as well as strengthening management of drugs in health centers.

This study aimed to investigate baseline data on malaria before the evaluation of new vector control strategies in an area of pyrethroid-resistance of vectors. The burden of malaria was estimated in terms of infection (prevalence and parasite density) and of clinical episodes.

Benin has recently shifted its national antimalarial drug policy from monotherapies to combinations containing artemisinin derivatives. When this decision was taken, the available information on alternatives to chloroquine and sulphadoxine-pyrimethamine, the first- and second-line treatment, was sparse.

Background: The role of agricultural practices in the selection of insecticide resistance in malaria vectors has so far been hypothesized without clear evidence. Many mosquito species, Anopheles gambiae in particular, lay their eggs in breeding sites located around agricultural settings. There is a probability that, as a result of farming activities, insecticide residues may be found in soil and water, where they exercise a selection pressure on the larval stage of various populations of mosquitoes. To confirm this hypothesis, a study was conducted in the Republic of Benin to assess the environmental hazards which can be generated from massive use of pesticides in agricultural settings. Methods: Lacking an HPLC machine for direct quantification of insecticide residues in samples, this investigation was performed using indirect bioassays focussed on the study of factors inhibiting the normal growth of mosquito larvae in breeding sites. The speed of development was monitored as well as the yield of rearing An. gambiae larvae in breeding sites reconstituted with water and soil samples collected in agricultural areas known to be under pesticide pressure. Two strains of An. gambiae were used in this indirect bioassay: the pyrethroid-susceptible Kisumu strain and the resistant Ladji strain. The key approach in this methodology is based on comparison of the growth of larvae in test and in control breeding sites, the test samples having been collected from two vegetable farms. Results: Results obtained clearly show the presence of inhibiting factors on test samples. A normal growth of larvae was observed in control samples. In breeding sites simulated by using a few grams of soil samples from the two vegetable farms under constant insecticide treatments (test samples), a poor hatching rate of Anopheles eggs coupled with a retarded growth of larvae and a low yield of adult mosquitoes from hatched eggs, was noticed. Conclusion: Toxic factors inhibiting the hatching of anopheles eggs and the growth of larvae are probably pesticide residues from agricultural practices. Samples used during this indirect assay have been stored in the laboratory and will be analysed with HPLC techniques to confirm hypothesis of this study and to identify the various end products found in soil and water samples from agricultural settings under pesticide pressure.

Within the context of WHO/CDS/RBM/2000, a survey was conducted in 2001 by the National Malaria Control Program of Benin. Following a well-thought-out choice, the survey took place simultaneously in health areas corresponding to epidemiological regions. Morbidity due to malaria is very high among children under five years admitted in external clinic (44.3% of cases) and (46.5%) for hospitalization. The crude rate of mortality is 129%. The use of non-impregnated bednet is usually met in three health areas, where 47.4% of the household have at least one non-impregnated bednet versus 5.4% of household with impregnated bednets. Percentage of pregnant women sleeping under an impregnated bednet and following chemoprophylaxis is respectively 43.3% and 3.8%. Results obtained at the end of this database survey in 2001 have facilitated the definition of indicators of the process, results and impact which remain very useful for the implementation of the monitoring and assessment system of "Roll Back Malaria" in Benin.