Epidemic Intelligence Service Office, Surveillance Section, Epidemiolgy Branch, Communicable Disease Center, Bureau of State Services, Public Health Service, United States Department of Health, Education, and Welfare, Atlanta, Georgia
Ninety-four cases of malaria were reported to the Communicable Disease Center during 1958 from 23 states and Hawaii. Confirmed and presumptive cases numbered 72. Of these, 65 were of foreign origin. Thirty-three of these cases were in military personnel, the majority contracting their illness in eastern Asia (Korea 9, Philippines 9). A total of 32 civilian cases of foreign origin came from 17 different nations. Mexico with 7 cases still leads the list although the numbers of cases acquired in Mexico has been dropping rapidly in recent years. The malaria eradication campaign in Mexico is considered to be a major factor in this decline.
Only three naturally acquired indigenous cases were reported—one from California, one from Arizona, and one from Pennsylvania. The actual places of origin of these cases could not be determined and no associated cases or endemic foci were found.
Four cases apparently resulting from blood transfusions were reported. A blood donor for one of these cases was identified as having a silent P. malariae infection, implying that, in 1958, the risk of acquiring malaria in the United States was greater from blood transfusions than from natural causes. The occurrence of these transfusion-acquired cases suggests the possibility that there may be numerous silent malaria infections in this country. These silent parasitemias do not, however, appear to be an important source of plasmodia capable of introducing the infection into the mosquito population and creating endemic foci.
As long as malaria prevails in other parts of the world, the threat of malaria outbreaks in the United States remains. Anopheline mosquitoes are abundant and their opportunities for survival increase with the increasing amount of land under irrigation. Only through careful surveillance of malaria and investigation of each reported case with the promptness and vigor customary in the investigation of cases of smallpox or plague can we preserve the near freedom from malaria we are currently enjoying.