[Experimental studies on the incubation period and relapse patterns in vivax malaria in west Hunan]

The paper reports on some biological characteristics of Plasmodium vivax isolated from Cili County of Hunan Province. 27 volunteers inoculated with sporozoites were observed for 1.5 to 2 years. Treatment with chloroquine 1.5g base for 3 days was initiated on the first day of the primary attack and of each relapse. The data indicate that the first latent period in 13 cases developing malaria after short incubation period is very long, being 243.4 (191-297) days; however it is always short, being 55.3 (51-80) days in 14 patients with long incubation period. Definite relationship existing between incubation period and relapse patterns in vivax malaria is thus demonstrated.