An epidemiological survey of echinococcosis in intermediate and definitive hosts in Qinghai Province, China

In order to understand the epidemiological status of alveolar and cystic echinococcosis in intermediate and definitive hosts in Qinghai Province, China, during the period 2007-2011, we investigated the infection in humans and animals, including yaks, Tibetan sheep, Tibetan dogs, and wild foxes distributed in different counties around the province. Sera from local residents were examined using a rapid serodiagnostic kit to detect specific antibodies against Echinococcus. Seropositive samples were confirmed with B-scan ultrasonography and X-ray examinations. Yaks and Tibetan sheep were checked at slaughterhouses, and cysts and suspicious lesions were collected for analysis. A rapid diagnostic strip was used to detect Echinococcus adults in Tibetan dogs. Positive dogs were dewormed and the parasites collected. Wild foxes were trapped and necropsies performed with particular attention to the intestine. Forty-eight of 735 (6.4%) humans tested were positive and 475 of 854 (55.6%) Tibetan sheep and 85 of 352 (24.15%) yaks were infected with Echinococcus. Across different counties, 214 of 948 (22.57%) Tibetan dogs were positive, and five of 36 (13.9%) wild foxes were infected with Echinococcus. Molecular studies showed that all the infections detected in humans, domestic yaks, and Tibetan sheep were the G1 genotype (E. granulosus), whereas the parasites from Tibetan foxes and Tibetan dogs were E. shiquicus and E. multilocularis, respectively. In conclusion, Echinococcosis is hyperendemic in Qinghai Province in both its intermediate and definitive hosts and the G1 genotype of cystic Echinococcus is the dominant strain.