Epidemiology of human hookworm infections among adult villagers in Hejiangand Santai Counties, Sichuan Province, China

Hookworm infection as well as other intestinal nematodiases are endemic to Sichuan Province in China. In order to research the prevalence and intensit y of these infections we visited two villages in Hejiang County (southern S ichuan Province) and Santai County (northwestern Sichuan Province) between July and October of 1997. Fecal examinations were performed on adult villag ers over the age of 15 years (currently children under this age are deworme d annually with anthelmintic drugs). Among 310 residents of Lugao Village ( Hejiang County), 87, 63 and 60% were infected with hookworm, Ascaris or Tri churis, respectively. The prevalence of hookworm determined to rise linearl y with age (r = 0.97). High intensity infections with hookworm still occur in this region as 22% of the residents have over 3000 eggs per gram (PEG) o f feces as determined by quantitative egg counts. The majority of these ind ividuals harbored mixed infection with Necator americanus and Ancylostoma d uodenale, although the former predominated when adult hookworms were collec ted from 30 village residents treated with pyrantel pamoate. In contrast, a mong the 334 Xinjian villagers examined (Santai. County) the majority harbo red predominantly light hookworm infections-66.1% of the residents has less than 400 EPG by quantitative fecal examination and only 3.7% exhibited gre ater than 3000 EPG. Again, N. americanus was the predominant hookworm seen after worm expulsion. We have round that despite economic development which is occurring in some parts of China, significant hookworm infections and c linical hookworm anemia still exist in areas of Sichuan Province. In Hejian g County we found that the intensity of hookworm infection has actually ris en within the last 10 years. Hookworm is a medical problem among the elderl y in Sichuan. (C) 1999 Elsevier Science B.V. All rights reserved.