Robert Vincent, Sokhna C.S., Rogier C., Ariey F., Trape Jean-François. (2003). Sex ratio of Plasmodium falciparum gametocytes in inhabitants of Dielmo Senegal. Parasitology, 127 (1), p. 1-8.
Titre du document
Sex ratio of Plasmodium falciparum gametocytes in inhabitants of Dielmo Senegal
Année de publication
2003
Type de document
Article
Auteurs
Robert Vincent, Sokhna C.S., Rogier C., Ariey F., Trape Jean-François
Source
Parasitology, 2003,
127 (1), p. 1-8
An epidemiological survey was conducted during a 4-month period of intense malaria transmission in Dielmo, a holoendemic Senegalese village. Two thick blood smears per inhabitant were collected weekly. The sex ratio of Plas-
modium falciparum gametocytes (gamete precursors) was studied in 50 gametocyte carriers. All age classes were represented (mean 19.7 years ; range : 2 months-75 years) ; 42 (84 %) of them did not receive antimalarial treatment. Overall
668 thick smears were examined until 100 gametocytes had been counted or for 40 min. A total of 11 204 gametocytes were observed with a mean sex ratio of 0.346 (95 % CI 0.317-0.374), i.e. 2.89 females per 1 male. Among the 284 thick
smears in which at least 10 gametocytes were observed, the mean percentage of male gametocytes was 27.8%, with a range of 0-82 %. Great variability was observed between gametocyte carriers and also between thick smears from the same
gametocyte carrier. A multivariate analysis was performed which highlighted the fact that only 2 variables had a significant effect on the sex ratio. Anaemia was associated with an increased percentage of males (Prevalence Rate Ratio [PPR] of male
gametocytes was multiplied by 1.65 if haematocrit rate <32 %) and a wave of gametocytes was associated with an increased percentage of female gametocytes (PRR was multiplied by 0.48 during the peak of gametocytaemia and for the 2 weeks
following this peak). The variables without significant effect on sex ratio were: age, sex, clinical status and sickle cell trait status of the gametocyte carrier, density of asexual parasites, quinine treatment, and gametocyte density (when taking
account of its waves). These results are discussed in regard of possible differential production, mortality or sequestration of one gametocyte sex and selective advantages for the transmission of parasites.
Plan de classement
Epidémiologie du paludisme [052ANOPAL03]
Descripteurs
PALUDISME ; AGENT PATHOGENE ; SEX RATIO ; SANG ; DENSITE ; GENOTYPE ; ANEMIE
