Enhanced gametocyte production in Fansidar-treated Plasmodium falciparum malaria patients: implications for malaria transmission control programmes.

Gametocytes are the agents in malaria transmissible between the vertebrate host and the mosquito vector, and an increase in their incidence would be expected to have a corresponding impact on the prevalence of malaria, particularly in areas of high transmission. The purpose of this study was to determine whether there is an association between the type of antimalarial drug administered and the production of gametocytes. Two commonly used drugs, Fansidar and chloroquine, were compared in this respect. A total of 94 people (mean age +/- s.d. 16.94 +/- 19.03 years), from a highly endemic malaria area of Zambia, were treated with either Fansidar or chloroquine (Fansidar, n = 46, chloroquine, n = 48). The percentages of gametocytes generated after treatment were 23.9 for Fansidar and 6.2 for chloroquine. A 2 x 2 table analysis of the data shows that the P values, both by chi 2 and Z analysis, were less than 0.02, suggesting a statistically significant difference in the propagation of gametocytes between the two treatment groups. There was no significant difference in the quantitative gametocyte count per 200 white blood cells (Fansidar, 7.5 +/- 8.57; chloroquine, 4.5 +/- 1.64; P > 0.10), probably because of the small size of the 'gametocyte' sample (n = 14).