Occurrence of Taenia species in pigs in slaughterhouses in Phu Tho province, northern Vietnam

Pigs act as the intermediate hosts of the zoonotic tapewormsTaenia soliumandTaenia asiatica, as well as of the non-zoonoticTaenia hydatigena.In Vietnam, human taeniasis and cysticercosis have been reported throughout the country; however, data on porcine cysticercosis are scarce. Our study aimed to estimate the prevalence ofTaeniaspp. in slaughtered pigs in two districts in Phu Tho, a mountainous province in northern Vietnam from where neurocysticercosis patients commonly originate. The carcasses of 399 pigs from 51 small-scale abattoirs were checked for cysticerci, while tongue, liver, masseter muscles, diaphragm and heart were sliced and examined. Retrieved cysticerci underwent polymerase chain reaction-restriction fragment length polymorphism and sequencing for species confirmation. Blood was also collected to detect antibodies by lentil lectin-purified glycoprotein enzyme-linked immunoelectrotransfer blot (LLGP-EITB) and recombinant T24H antigen (rT24H)-EITB and circulating antigens by B158/B60 Ag-ELISA. In two pigs,T. asiaticacysticerci were found, confirming the presence of the parasite in pigs in Vietnam at a low prevalence (0.5%; 95% exact confidence interval (CI): 0-1.19%). Cysticerci ofT. soliumwere found in none of the pigs, although one serum sample was positive for antibodies in both LLGP-EITB and rT24H-EITB. Furthermore, a high prevalence ofT. hydatigenacysticercosis was observed (18.0%; 95% Wilson score CI: 14.6-22.1%). In more than half of theT. hydatigena-positive pigs, circulating antigens were detected by Ag-ELISA, confirming that this test cannot be used to diagnoseT. soliumcysticercosis in this region. Finally,Spirometra erinaceieuropaeiwas found in one pig liver. It is the first record of this zoonotic cestode species in pigs in Vietnam. Overall, the findings confirmed the complex epidemiology ofTaeniaspp. in pigs in Vietnam.