Helminth infections in dogs in Phu Tho Province, northern Vietnam.

Helminths are among the most-commonly encountered disease-causing agents in dogs all over the world, including Vietnam. A cross-sectional survey was carried out between March and December 2019 in four dog slaughter-slabs in Yen Lap District, Phu Tho Province, northern Vietnam, aiming to reveal the occurrence of gastrointestinal helminths in dogs. Worms were collected from 350 dog samples and identified by morphological techniques followed by molecular methods for tapeworms and hookworms. Nine species, including Taenia hydatigena, Spirometra erinaceieuropaei, Dipylidium caninum, Spirocerca lupi, Ancylostoma ceylanicum, Ancylostoma caninum, Toxocara canis, Toxascaris leonina and Trichuris vulpis, were found to occur in this area. Infection with at least one worm species was found in 272 dogs (77.7%; 95% Wilson score CI: 73.1-81.8%). The most common species was A. ceylanicum, with a prevalence of 45.1% (95% Wilson score CI: 40.0-50.4%) while T. hydatigena had a very low prevalence of 0.3% (95% Exact CI: 0.0-1.6%). Co-infection with hookworms and D. caninum was common. Five of the recovered helminth species have a zoonotic potential. Control of these parasites is necessary in order to protect human and animal health.

Prevalence, genotyping and risk factors of Giardia duodenalis from dogs in Vietnam.

This study was carried out to determine the prevalence, genotypes/assemblages and possible risk factors associated with Giardia duodenalis infection in dogs in central Vietnam. A total of 209 dog fecal samples, randomly collected from private owned dogs (n=105) and dogs from stores (n=104), were examined for Giardia cysts by microscopy. Positive samples were genotyped by PCR-sequence analysis of ß-giardin and triosephosphate isomerase genes markers. Risk factors were studied using a structured questionnaire and collected data were analyzed by univariate and multivariate logistic regression analyses. Results indicated that the overall infection rate was 8.6% (18/209) with the detected parasites were belonging to the non-zoonotic assemblages C and D. Age, gender and origin of animals were the main risk factors associated with G. duodenalis infection in dogs under study. Occurrence of infection was more likely in young animals compared to old ones and in females compared to males. Dogs originated from stores were more prone to Giardia infection compared to private owned counterparts.

Opisthorchis viverrini infection in the snail and fish intermediate hosts in Central Vietnam.

Opisthorchis viverrini, a carcinogenic fish borne fluke, requires freshwater snails and fish as intermediate hosts. Opisthorchiasis is endemic in parts of Southeast Asia, including Central and South Vietnam. In this region the transmission by intermediate hosts has received little attention. Therefore, freshwater snails and wild fish from Bau My Tho, an opisthorchiasis endemic area in Binh Dinh Province were collected for examination of O. viverrini cercariae and metacercariae, respectively. A total of 12,000 snails belonging to six families, of which 1616 Bithynia snails representing Bithynia siamensis goniomphalos and Bithynia funiculata; as well as 754 fish representing 12 species were examined. Shedding of O. viverrini cercariae was observed only in B. s. goniomphalos and B. funiculata, at infection rates of 0.86% and 0.14%, respectively. O. viverrini infection in Bithynia spp. was significantly associated with the habitat but not with the species and the shell size of Bithynia spp. O. viverrini metacercariae were found in 10 fish species representing both Cyprinidae and non-Cyprinidae families. The prevalence of O. viverrini infection in fish was significantly associated with species. Carassius auratus, a fish species commonly eaten raw, Rasbora aurotaenia and Puntius brevis had the highest prevalence of 74.0%, 55.8% and 31.6%, respectively. Sharing of the same snail and fish intermediate host species was found for O. viverrini and a O. viverrini duck-genotype that are sympatric in the study region. This study is the first to report on the intermediate host species of O. viverrini in Central Vietnam and indicates a high risk of acquiring opistorchiasis when eating raw fish dishes.