Trichinella infection in wild boars and synanthropic rats in northwest Vietnam.

Trichinellosis is an emerging parasitic zoonosis in North Vietnam. In this survey, hunted and farm-bred wild boars as well as synanthropic rats were sampled in two provinces of northwest Vietnam where outbreaks of trichinellosis have recently occurred. Evidence of Trichinella infection was studied by parasitological, serological and molecular methods. The results showed relatively low prevalence of Trichinella spiralis in hunted wild boars (2/62 (3.2%; 95% CI: 0.8- 4.8)) and rats (23/820 (2.8%; 95% CI: 13.7-32.3)). Parasite burdens in the muscle tissues were between 0.1 and 0.03 larvae/g, and 0.1 and 7 larvae/g in wild boars and rats, respectively. Seroprevalence in farm-bred wild boars was negative. The findings of Trichinella-infected rats in 7 of the 20 districts of Dien Bien and Son La provinces suggest that the parasite is circulating in these regions. These results indicate that the local population and health centers should be made aware of the risks of eating raw or undercooked meat dishes prepared from wild animals.

Seroprevalence of trichinellosis in domestic animals in northwestern Vietnam.

Trichinellosis is an important emerging or re-emerging zoonotic disease in Southeast Asia. In Vietnam, data on trichinellosis are scarce. Therefore, the present study was designed to determine the seroprevalence of trichinellosis in the domestic lifecycle in two provinces of northwestern Vietnam, where recently isolated outbreaks of human trichinellosis occurred. Serum samples were obtained from 558 pigs, 125 dogs and 98 cats, transported on filter paper, and tested for Trichinella antibodies by ELISA and Western blot, using larval excretory-secretory (E/S) antigens. The overall seroprevalence of antibodies to Trichinella was 5.6%, 4% and 0% in pigs, dogs and cats, respectively. In pigs, positive cases were distributed in 8/20 districts of the two provinces. This study suggests that Trichinella spp. is circulating in the domestic life cycle in northwestern Vietnam. Further study is recommended to investigate the presence of Trichinella in a sylvatic cycle, and to identify the occurring Trichinella species.