P. falciparum malaria prevalence among blood donors in Bamako, Mali.

AIM: Malaria parasite is usually transmitted to humans by Anopheles mosquitoes but it can also be transmitted through blood transfusion. Usually malaria transmission is low in African urban settings. In West Africa where the P. falciparum is the most predominant malaria species, there are limited measures to reduce the risk of blood transfusion malaria. The aim of this study was to evaluate the prevalence of P. falciparum malaria carriage among blood donors in the National Blood Center of Bamako, capital city of Mali. METHODS: The study was conducted using a random sample of 946 blood donors in Bamako, Mali, from January to December 2011. Screening for malaria was performed by thick smear and rapid diagnostic test (RDT). Blood group was typed by Beth-Vincent and Simonin techniques. RESULTS: The frequency of malaria infection was 1.4% by thick smear and 0.8% by the RDT. The pick prevalence of P. falciparum malaria was in rainy season, indicating a probable high seasonal risk of malaria by blood transfusion, in Mali. The prevalence of P. falciparum infection was 2% among donors of group O the majority being in this group. CONCLUSION: There is a seasonal prevalence of malaria among blood donors in Bamako. A prevention strategy of transfusion malaria based on the combination of selection of blood donors through the medical interview, promoting a voluntary low-risk blood donation and screening all blood bags intended to be transfused to children under 5, pregnant women and immune-compromised patients during transmission season using thick smear will reduce the risk of transfusion malaria in Mali.

Entomological and parasitological parameters of malaria transmission in Douguia, Chad.

Malaria remains a threat for many countries, especially in Chad where it is the leading cause of morbidity and mortality. Few reliable data exist, however, about the entomological and parasitological parameters of malaria transmission. The objective of this study was to investigate the entomological and parasitological parameters of malaria transmission in Douguia, a village located 75 km northeast of Ndjamena (Chad), as part of a training program for participants in Chad's malaria control program. Mosquitoes were collected after morning pyrethroid spraying, with a mouth aspirator. The parasitological data were collected by a rapid diagnosis test or microscopic examination. The study examined 350 subjects aged from 6 months to 80 years. The plasmodic index (PI) of Plasmodium falciparum was 25.4 % (n = 89) and the gametocygenic index (GI) 9.1 % (n = 32); they varied significantly from one age group to another (p = 10- 3). The PI in pregnant women attending antenatal clinics was 18.7 % (n = 12/64). Three Anopheles species were found: Anopheles gambiae s.l, An. arabiensis and An. pharoensis. An. coluzzii accounted for 94.9 % of the An. gambiae s.s. The antigen sporozoite index (SI) was 4.5 %. Our results confirm the endemicity of malaria in Chad (Douguia) and underline the major role of An. gambiae s.l. in its transmission. However, repeated studies using PCR for Plasmodium detection would help to improve our understanding of its epidemiology.