High heterogeneity in the number of Plasmodium falciparum gametocytes in the bloodmeal of mosquitoes fed on the same host

G. PICHON a1c1, H. P. AWONO-AMBENE a2a3 and V. ROBERT a2
a1 Institut de Recherche pour le Développement (ex ORSTOM), Laboratoire d'Informatique Appliquée, Bondy, France
a2 Institut de Recherche pour le Développement, Laboratoire de Paludologie, B.P. 1386, Dakar, Sénégal
a3 Université Cheikh Anta Diop, Faculté des Sciences, Départment de Biologie animale, Dakar, Sénégal


To investigate the quantitative distribution of Plasmodium falciparum gametocytes into the vector bloodmeal, Anopheles arabiensis mosquitoes were fed on 3 volunteers naturally infected with gametocytes. The content of each mosquito midgut was smeared on a microscope slide and Giemsa stained. The distribution of gametocytes ingested by mosquitoes followed a negative binomial distribution, with apparently constant overdispersion (parameter k±S.E. = 3·105±0·392) for the 3 series. This aggregation of gametocytes in some midguts probably facilitates the conjunction of gametes and fertilization. This suggests that P. falciparum gametocytes in the peripheral blood flow of infected man do not follow an independent, homogeneous pattern but show a significant aggregation.

(Received November 9 1999)
(Revised February 24 2000)
(Accepted February 24 2000)

Key Words: Plasmodium falciparum; gametocyte; mosquito; aggregated distribution; malaria transmission.

c1 Corresponding author: IRD, Laboratoire d'Informatique Appliquée, 32 Avenue Henri Varagnat 93143 Bondy Cedex, France. Tel: +33 1 4802 5976. Fax: +33 1 4847 3088. E-mail: