1.The malaria survey in Cuba, which is planned eventually to include the whole island, has been completed now in Pinar del Río Province and the data are reported here.
2.In the Province of Pinar del Río 16,855 children have been examined for splenomegaly and 7,407 for malaria parasites. The results of the latter examinations show a significantly higher frequency of children with malaria parasites among those with splenomegaly than in the spleen negative group.
3.Plasmodium vivax and Plasmodium falciparum are well distributed throughout the area. The former occurs almost twice as frequently as the latter.
4.The endemicity of malaria is moderate in those portions of the counties of Mantua, Guane, Consolación del Sur, San Luis, and Viñales which lie in the low coastal plain. In the remainder of the province the malaria problem is one of light endemicity, with recurring epidemics when conditions are unusually favorable to the breeding of anophelines capable of transmitting the disease.
5.Five species of anopheline mosquitoes have been encountered in the area. These are: A. albimanus, A. crucians, A. grabhami, A. vestitipennis, and A. atropos.
6.A study of the distribution of these anophelines in the area confirms the fact that A. albimanus is present in far greater numbers in the coastal plain area, where most malaria was encountered. The season of maximum prevalence of this mosquito coincides with the malaria transmission season. It is known to be a malaria vector, and it is reasonable to conclude that it is the important malaria vector in Pinar del Río Province.