[Study of the incidence of malaria in febrile patients and among schoolchildren in the region of Trarza, Islamic Republic of Mauritania].

A study was performed to appreciate the importance of malaria in the low valley of the Senegal River North Bank in Mauritania. The malaria incidence was assessed among patients visiting the regional hospital of Rosso (Trarza region) for a "presumptive malaria", a diagnosis assigned by the clinicians based on fever and other suggestive symptoms of malaria. The malaria prevalence rate was also measured in schoolchildren. A total of 1431 febrile outpatients were sampled for thick and thin blood films, between December 2004 and March 2005, August and November 2005, and April and July 2006. The average malaria prevalence rate was 2.5% (36/1431). It varied from 0.7% (4/576) for the period from December 2004 to March 2005 to 3.8% (18/475) from August to November 2005 and 2.1% (8/380) from April to July 2006. Of the 1040 school children of 6 to 14 years of age, the average malaria parasite prevalence rate was 0.9% (9/1040). It was 0.4% (1/224), 1.7% (7/413) and 0.2% (1/402), Respectively, in February 2004 (cold and dry season), October 2005 (rainy season) and June 2006 (hot and dry season). These very low levels of malaria endemicity and incidence are comparable with those recorded in the same area on the (South) bank of the river in Senegal. In this context of unstable malaria, characterized by the absence or a low level of natural immunity of the population, an effective monitoring is essential for an early detection and a damming up of the malaria epidemic blazes that likely occur.