1.The malaria survey of Cuba, which is eventually to include the whole Island, has been extended to all of the Province of Oriente and to part of the Provinces of Pinar del Río and Havana.
2.In the Province of Oriente 22,203 children have been examined for splenomegaly, and 9,713 blood films have been examined for malaria parasites. The results of the examinations show a significantly higher frequency of children with malaria parasites among those with splenomegaly than in the spleen negative group, and indicate that the splenomegaly is probably due to malaria.
3.P. vivax and P. falciparum are well distributed throughout the area surveyed, and the frequency of infection with the latter is only slightly greater than that of the former.
4.The endemicity of malaria in Oriente Province is low, and one would expect epidemics from time to time when local conditions favor the breeding of anophelines capable of transmitting the disease.
5.Five species of Anopheles have been encountered in the area surveyed. These are A. albimanus, A. crucians, A. grabhami, A. vestitipennis, and A. atropos.
6.A study of the distribution of the various anophelines in these areas shows that A. albimanus is present in overwhelming abundance where evidence of malaria was encountered. Studies elsewhere have shown that the season of maximum prevalence of this mosquito coincides with the malaria transmission season, and it is reasonable to suppose that A. albimanus is the important vector in Oriente Province.