[Malaria in Vietnam. Environment, prevention and treatment]

In Viet-nam, malaria rages in mountainous and wooded areas, as well as in coastal areas. In these geographical zones, the diversified features of environment have different repercussions on the development of Anopheles species. The main vector species have strict oecological requirements: An. dirus, disseminated in the forests, colonizes stagnant and shaded water, such as rain water collected in ground dips and in cavities of trees and rocks; An. minimus selects its breeding-sites in pure and slightly current streamlets, in the hilly areas. On the contrary, An. sundaicus, first-rate coastal vector, adjusts itself to diversified biotopes, which nevertheless all have common features: saltiness of water (optimum 1-7 g NaCl/litre), faint sunning, stagnant or slightly current water, with floating green algae (Ceratophyllum, Najas). P. falciparum prevails in the wooded areas (P. f.: 75%; P. v.: 25%); but in the coastal areas where Anopheles hyrcanus pullulates, P. vivax reaches the same ratios as P. falciparum. In Viet-nam, the prevention and antimalarial fight are centred on three measures: diagnosis, treatment and watching of diseases, antivectorial fight, antimalarial fight combined with first medical care. Owing to the spreading of P. falciparum chemoresistance to chloroquine (27 to 76%) and to Fansidar (22 to 83%), we had to have recourse to new antimalarials: artemisinine and artesunate tested in several regions of the country (tests in vitro and in vivo during 28 days) revealed their high schizonticidal capacity, but the recrudescence reached 30 to 50%.(ABSTRACT TRUNCATED AT 250 WORDS)