Disease Intelligence Center, Department of Health, United States Naval Medical Research Unit No. 2, Department of Preventive Medicine, University of Washington, Taipei, Taiwan, Republic of the Philippines
An epidemic of a chronic wasting disease, caused by a previously unknown nematode. Capillaria philippinensis, was discovered to be occurring along the northwest coast of Luzon. Philippines. A study was undertaken to elucidate by epidemiologic methods the possible mode of spread of the new disease, intestinal capillariasis, in Pudoc West, the site of the first cases and the most heavily infected village. A census of the village was conducted and the date of onset of capillariasis determined by interview for each case. Stool surveys were done of the entire village and individual families followed more closely for occurrence of new cases. Thirty-two percent of the population and capillariasis during the 2½ years since the beginning of the epidemic. The fatality rate in males was 35%, 19% in females. An analysis of initial cases within households revealed that most were males, usually between the ages of 20 and 49, suggesting a relation between initial infection and occupation. The distribution of age and sex in subsequent cases and the general population were similar. In addition, the pattern of spread within families and within the village also suggested a direct mode of transmission of the disease.