Fasciola spp. in Southeast Asia: A systematic review.

BACKGROUND: Fasciolosis is an emerging public health threat in a number of regions worldwide. To date, we lack an overview of both its occurrence and distribution in Southeast Asia across all actors involved in the life cycle, which impedes the development of disease control measures. Therefore, our objective was to collect recent information on the distribution and the prevalence of Fasciola spp. and the associated risk factors for infection in humans, animals, snails and plant carriers in Southeast Asia. METHODOLOGY: Bibliographic and grey literature databases as well as reference lists of important review articles were searched for relevant records published between January 1st, 2000, and June 30th, 2022. The systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for reporting systematic reviews. A total of 3,887 records were retrieved, of which 100 were included in the final analysis. PRINCIPAL FINDINGS: The studies focused mainly on one host species (96.0%), with Fasciola spp. infection in animals being the most studied (72.0%), followed by humans (21.0%). Based on the used inclusion and exclusion criteria, reports were retrieved describing the presence of Fasciola spp. infection in seven out of 11 countries in Southeast Asia. Depending on the diagnostic tool applied, the prevalence of Fasciola spp. infection ranged between 0.3% and 66.7% in humans, between 0% and 97.8% in animals, and between 0% and 66.2% in snails. There were no studies reporting the presence of metacercariae on plant carriers. CONCLUSIONS/SIGNIFICANCE: Our study reconfirms that Fasciola spp. infections are widespread and highly prevalent in Southeast Asia, but it remains difficult to accurately assess the true occurrence of Fasciola spp. in absence of well-designed surveys covering all hosts. As next steps we propose to assess the occurrence of the infection across all actors involved in the transmission, to identify associated risk factors and to estimate the burden of the disease to support national and international decision makers.

Human Taeniasis and Cysticercosis and Related Factors in Phu Tho Province, Northern Vietnam

Several factors presumed to facilitate the transmission of Taenia spp. were reported in Vietnam. We conducted a cross-sectional study taking questionnaires from 1,185 participants, and collecting 1,151 sera and 1,036 stool samples in northern Vietnam. Sera were examined for circulating antigens of Taenia solium cysticerci using ELISA, stools for Taenia eggs by Kato-Katz smear, and copro-antigens by ELISA. Ag-ELISA revealed 4.6% antigen positivity, indicating infection with viable cysticerci. Taenia eggs were detected in 1.5% of participants. Copro-antigens were found in 2.8% of participants. Eating raw meat and/or vegetables was significantly associated with the presence of copro-antigen (OR=8.6, 95% CI: 1.16-63.9, P=0.01). Considering the high taeniasis prevalence and the associated threat, public health attention should be given to treat the tapeworm carriers in the projected areas.

Human Taeniasis and Cysticercosis and Related Factors in Phu Tho Province, Northern Vietnam

Several factors presumed to facilitate the transmission of Taenia spp. were reported in Vietnam. We conducted a cross-sectional study taking questionnaires from 1,185 participants, and collecting 1,151 sera and 1,036 stool samples in northern Vietnam. Sera were examined for circulating antigens of Taenia solium cysticerci using ELISA, stools for Taenia eggs by Kato-Katz smear, and copro-antigens by ELISA. Ag-ELISA revealed 4.6% antigen positivity, indicating infection with viable cysticerci. Taenia eggs were detected in 1.5% of participants. Copro-antigens were found in 2.8% of participants. Eating raw meat and/or vegetables was significantly associated with the presence of copro-antigen (OR=8.6, 95% CI: 1.16-63.9, P=0.01). Considering the high taeniasis prevalence and the associated threat, public health attention should be given to treat the tapeworm carriers in the projected areas.

Prenatal diagnosis and prevention of toxoplasmosis in pregnant women in Northern Vietnam: study protocol.

BACKGROUND: In Vietnam, no systematic prenatal toxoplasmosis screening is in place, and only few studies have assessed the prevalence and importance of this zoonotic parasite infection. In addition, no studies have been conducted to assess the risk factors associated with toxoplasmosis. This study protocol was developed to determine the seroprevalence of toxoplasmosis in pregnant women in Hanoi and Thai Binh, Northern Vietnam, and to evaluate the association with risk factors and congenital toxoplasmosis. The protocol was developed in a way that it could potentially evolve into a countrywide prenatal diagnosis and prevention program, with the main focus on primary prevention. METHODS: The collaborating gynaecologists will invite eligible pregnant women attending antenatal care for the first time to participate in the study. At first consult, information about toxoplasmosis and its prevention will be provided. All participants will be asked to fill in a questionnaire, which is designed to analyse socio-demographic and biologically plausible risk factors associated with toxoplasmosis, and blood samples will be collected to determine the seroprevalence of toxoplasmosis in pregnant women. In case there is suspicion of a primary infection during pregnancy, the concerned women will be followed-up by the gynaecologists according to a predefined protocol. Every participant will be informed on her serological status, risk factors and prevention measures and is offered appropriate medical information and medical follow-up if required. DISCUSSION: The hypothesis is that congenital toxoplasmosis is an important but currently under-diagnosed public health problem in Vietnam. This study can strengthen sustainable control of toxoplasmosis in Vietnam, provide a protocol for prenatal diagnosis, boost overall awareness, improve the knowledge about toxoplasmosis prevention and can be essential for evidence-based health policy.