Assessment of knowledge and practices regarding taeniasis and cysticercosis in Pak Chong, Nakhon Ratchasima, Thailand: A cross-sectional study.

BACKGROUND: Taeniasis and cysticercosis are parasitic infections caused by Taenia spp., mainly transmitted through the consumption of undercooked pork. Prevention requires increasing knowledge and awareness, improving meat inspection and hygiene, and promoting safe food handling and sanitation. The aim of this study was to evaluate the knowledge and practice (KP) of residents in Pak Chong District, Nakhon Ratchasima, Thailand, regarding taeniasis and cysticercosis. METHODS: A cross-sectional study was conducted in Pak Chong District, Nakhon Ratchasima, Thailand, and its 11 subdistrict municipalities. Study participants were selected using a stratified random sampling design. A validated questionnaire (Cronbach's alpha = 0.70) was used to collect socio-demographic information and assess knowledge and practices related to taeniasis and cysticercosis. Descriptive statistics and multiple linear regression were used for the analysis. RESULTS: Of the 360 survey respondents, 65.0% (n = 234) were women, 82.2% (n = 296) were aged under 60 years, 99.2% (n = 357) identified as Buddhist, 87.5% (n = 315) had less than a bachelor's degree education level, 54.2% (n = 195) had monthly family income ≥10,000 Thai baht, 10.6% (n = 38) were unemployed, and 26.1% (n = 93) lived in a town municipality. The survey revealed that 98.3% (n = 354) of participants were categorized as having less accurate knowledge and 83.6% (n = 301) were classified as more frequently engaging in correct prevention practices. Our study revealed that pig farmers (1.7%) occasionally permitted the pigs to forage freely. The results of multiple linear regression analysis revealed that knowledge scores were positively associated with household income ≥10,000 Thai baht (ßadj = 1.50, 95% confidence interval [CI] 0.65 to 2.36). Practice scores were negatively associated with age over 60 years (ßadj = -1.77, 95% CI -3.14 to -0.40) and living in a subdistrict municipality (ßadj = -2.58, 95% CI -3.77 to -1.39). There was no association between KP regarding taeniasis and cysticercosis in the population of Pak Chong. CONCLUSIONS: Overall, participants' knowledge was lacking. Public education interventions are recommended to improve knowledge among residents with low socioeconomic status. These findings can inform the development of targeted interventions and educational programs in Pak Chong District, especially among elderly people in subdistrict municipalities, to improve practices for the prevention and control of these parasitic infections.

Monoclonal Antibodies Targeting an Opisthorchis viverrini Extracellular Vesicle Tetraspanin Protect Hamsters against Challenge Infection.

Opisthorchis viverrini causes severe pathology in the bile ducts of infected human hosts, and chronic infection can culminate in bile duct cancer. The prevention of infection by vaccination would decrease opisthorchiasis-induced morbidity and mortality. The tetraspanin protein, Ov-TSP-2, is located on the membrane of secreted extracellular vesicles (EVs), and is a candidate antigen for inclusion in a subunit vaccine. To address the role of anti-Ov-TSP-2 antibodies in protection, we assessed the protective capacity of anti-Ov-TSP-2 monoclonal antibodies (mAbs) against opisthorchiasis. Two anti-TSP-2 IgM mAbs, 1D6 and 3F5, and an isotype control were passively transferred to hamsters, followed by parasite challenge one day later. Hamsters that received 3F5 had 74.5% fewer adult flukes and 67.4% fewer eggs per gram of feces compared to hamsters that received the control IgM. Both 1D6 and 3F5 (but not the control IgM) blocked the uptake of fluke EVs by human bile duct epithelial cells in vitro. This is the first report of passive immunization against human liver fluke infection, and the findings portend the feasibility of antibody-directed therapies for liver fluke infection, bolstering the selection of TSPs as components of a subunit vaccine for opisthorchiasis and fluke infections generally.

Orally Administered Bacillus Spores Expressing an Extracellular Vesicle-Derived Tetraspanin Protect Hamsters Against Challenge Infection With Carcinogenic Human Liver Fluke.

BACKGROUND: The human liver fluke Opisthorchis viverrini is a food-borne trematode that causes hepatobiliary disease in humans throughout Southeast Asia. People become infected by consuming raw or undercooked fish containing metacercariae. Development of a vaccine to prevent or minimize pathology would decrease the risk of severe morbidity, including the development of bile duct cancer. METHODS: We produced an oral vaccine based on recombinant Bacillus subtilis spores expressing the large extracellular loop (LEL) of O. viverrini tetraspanin-2 (Ov-TSP-2), a protein that is abundant on the surface of O. viverrini secreted extracellular vesicles (EVs). Recombinant spores expressing Ov-TSP-2-LEL were orally administered to hamsters prior to challenge infection with O. viverrini metacercariae. RESULTS: Vaccinated hamsters generated serum IgG as well as bile IgG and IgA responses to Ov-TSP-2-LEL, and serum IgG from vaccinated hamsters blocked the uptake of fluke EVs by a human bile duct epithelial cell line. Vaccinated hamsters had 56% reductions in both adult flukes and fecal eggs compared to the control group. CONCLUSIONS: These findings indicate that oral vaccination of hamsters with recombinant B. subtilis spores expressing Ov-TSP-2-LEL is efficacious at reducing infection intensity and could form the basis of a vaccine for control of carcinogenic liver fluke infection in humans.