Severe malaria attack is associated with high prevalence of Ascaris lumbricoides infection among children in rural Senegal.

In human populations, the concomitance of various parasitic infections can induce modifications of the specific immune response to each pathogen and thus induce changes in their clinical expression. Several studies, however, have produced conflicting results. To study the hypothesis that there is an association between helminthiasis and the occurrence of severe malaria a prospective case-control study was carried out in a rural zone of Senegal where 105 presumptive severe malaria attacks were studied in 2001 and 2002. Following parasitological control the cases were divided into two groups: A (severe malaria) with severe symptoms and parasite density >5000 parasites/microl (n = 64) and B (other causes) with severe symptoms and negative or weak parasite density (n = 41). In group A the prevalence of Ascaris lumbricoides infection was higher in cases of severe malaria than in controls, odds ratio (OR) = 9.95 (95% CI 3.03-32.69). Similar but not significantly different results were observed between patients in group B and their controls, OR = 2.47 (95% CI 0.95-6.38).