An entomological survey in the Sudanese Guinean environmental transition zone after indoor residual spraying, Chad

Introduction: malaria is a major public health issue in Africa. In Chad in 2019, with 955,243 confirmed cases and 2,955 deaths, malaria is the main cause of consultations. A longitudinal entomological study was conducted in Moïssala Health District. Its objective was to assess the impact of indoor residual spraying with 80% bendiocarb wettable powder on malaria transmission. Methods: two areas were defined for the study: Dembo, located in the sprayed area, Moïssala, in the untreated area. Two sampling methods were used: pyrethrum spray catches and human landing catches. Results: sixteen sessions of human landing catches totalling 32 man-nights were conducted and 160 rooms/site were sprayed. Two anopheles were captured in Dembo and 547 in Moïssala. In Moïssala, An coluzzii, An funestus and An rufipes were captured in the rooms and on human bait. An colluzzii and An funestus were captured in pyrethrum spray catches in Dembo. The anophelian human landing catches density was zero in Dembo while it was 8.38 bites/man/night in outdoor and 10.06 bits/man/night in indoor in Moïssala. Only An coluzzii was found infected in human landing catches and sporozoite index of was 7.46% (10/134) in outdoor and 7.45% (12/161) in indoor in Moïssala. Malaria transmission was estimated at 0.63 infected bites/man/night in outdoor and 0.75 infected bites/man/night in indoor i.e. 229.95 infected bites/man/year in outdoor and 273.75 infected bites/man/year. In pyrethrum spray catches, An coluzzii and An rufipes were the two species found infected in Moïssala with sporozoite indices of 6.70% (23/343) and 20% (2/10) respectively. However, in Dembo, neither of the two captured mosquitoes was found infected. Conclusion: the indoor residual spraying campaign in the eastern zone of Moïssala has led to the collapse of vectors´ density and aggressiveness. However, its evaluation over a short period of time is not sufficient to assess the impact of malaria transmission in this constant and endemic malaria zone

Seroprevalence, geographical distribution, and risk factors of peste des petits ruminants in the Republic of Chad

Objective: The objective of this study was to determine the prevalence, geographical distribution, and main risk factors for peste des petits ruminants (PPR) in the Republic of Chad. Materials and methods: A total of 3,546 sera collected from unvaccinated small ruminants including 1,699 goats and 1,847 sheep in 19 of the 23 regions in Chad were randomly sampled. The competitive enzyme-linked immunosorbent assay technics were used for serological analysis. Results: The overall seroprevalence at the individual level was 52.9%±1.6% (48.9% for goats and 56.2% for sheep). Seroprevalence observed in the Chari Baguirmi, Ouaddaï, and NDjamena regions was significantly higher than those in the other regions. Transhumant herds are the most exposed than the sedentary ones. Older animals were more affected than the young ones. Kababich sheep are the most affected than other breeds. Conclusion: This study has shown that the PPR virus is circulating in the Republic of Chad. In view of the results obtained, the disease is enzootic in the country. Epidemiological information obtained including seroprevalence rate, risk factors (sex, breed, age, and mode of rearing), and geographical distribution will help to define an appropriate strategy for PPR control in the Republic of Chad. [J Adv Vet Anim Res 2018; 5(4.000): 420-425