Approaching One Health model to control pediculosis transmitted to humans and animals through food in Vietnam
Dr. Bui Thi Dung reported the acceptance of the project results on 31/7/2023
Pediculosis is transmitted to humans and animals through food common in Southeast Asia, due to the ingestion of vegetables with large fascioliasis pathogens and from fish with small liver flukes or intestinal flukes. An extremely serious complication associated with these chronic changes is the development of cholangiocarcinoma. Cattle infected with large liver flukes can die en masse.
In Vietnam, the prevalence of human fluke infection is relatively high and has been previously reported in the northern provinces. The project has implemented research in 2 provinces of Yen Bai and Thanh Hoa. In these areas, the habit of eating raw or undercooked fish and raw vegetables is very common and the majority of the fish supply is from natural rivers and lakes. Therefore, education and communication are key factors in pediculosis prevention in Viet Nam. Although the knowledge, attitude and practice of local people are still relatively low, after being communicated such as: distributing leaflets, posting posters, information through local speakers, reporting on information about pediculosis and transmission routes as well as how to prevent it, knowledge, people's attitudes and practices on pediculosis prevention have improved. Therefore, an approach to One Health Model for integrated control of pediculosis in humans and animals is essential.
In order to achieve the objectives of the project, there has been close multidisciplinary cooperation between Belgian and Vietnamese partners: Health (Free University of Brussels, Institute of Tropical Medicine – Belgium and National Institute of Malaria and Insect Parasitology – Vietnam), Veterinary Medicine (University of Liège – Belgium, Institute of Veterinary Medicine – Vietnam), Fisheries (University of Namur – Belgium, Aquaculture Research Institute 1 – Vietnam) and Environment (University of Liège – Belgium, Institute of Ecology and Biological Resources – Vietnam). The project was implemented from 2017 to 2023 and was accepted by the Excellent Acceptance Evaluation Council with the results of research, training and scientific products achieved.
Belgian experts provide technical training to local health workers
The survey results of the project showed that: the rate of infection with small liver flukes in humans in both provinces was 40.2%, large liver flukes 5.64%, intestinal flukes 15.9%. The prevalence of flukes is higher in men than in women, and is common between the ages of 31-50 years. The prevalence of fascioliasis and intestinal fluke in dogs and cats was 19.6% and 47.1% in Yen Bai, and 10.4% and 11.8% in Thanh Hoa, respectively. The prevalence of fascioliasis in both provinces was 19.4%. Fish species infected with small liver fluke larvae: oilfish, ditchfish, miniature fish. All 10 species of fish tested were infected with intestinal fluke larvae. The snail serves as an intermediate host of the small liver fluke: Parrafosarulus striatulus. The snail serves as an intermediate host of the large liver fluke: Austropeplea viridis. Biological control of fluke eggs in animals: for small-liver fluke eggs using the fungal strain VTCC 31150 Trichoderma koningii, for large liver fluke eggs using the fungal strain 30706 Paecilomyces lilacinus. Snail biological control by nematodes: Heterorhabditis indica DL1 strain (150 IJs/10 μl) causes mass death, Phasmarhabditis hermaphrodita strain can reproduce in snail carcasses. Snail biological control with essential oils (mint, basil, lemongrass and cinnamon) can cause complete death of Austropeplea viridis snails at concentrations of more than 0.125%, and their toxicity is dose-dependent. 55% alcohol can inactivate the metacercaria cyst of the small liver fluke after 60 hours. Acetic acid and potassium permanganate are capable of destroying the metacercariae of large liver flukes in concentrations of (62-66%) and (38-66%), respectively.
The project also confirmed the circulation of small liver flukes, intestinal flukes, and large liver flukes in Yen Bai and Thanh Hoa provinces. However, because diseases caused by helminths in general and flukes in particular do not kill as quickly as diseases caused by viruses or other infectious diseases, very little attention is paid to by agencies and policy makers, although pediculosis harms human health in a smoldering way and persists for a long time in the human body. Therefore, continuous and long-term communication is really necessary. Parallel activities such as awareness raising and capacity building have been implemented. Awareness campaigns were organized for local people and capacity building for researchers and health workers at provincial, district and commune levels.
Leaflets distribute to residents and students, Propaganda posters
Lecture on flukes to students and residents
Communication to raise people's awareness about flukes and how to prevent them
The project has published 05 articles in the prestigious ISI journal, 05 articles in the prestigious national journal; training and transferring parasite diagnostic techniques (ELISA technique, flukefinder technique, ethyl formalin technique, Kato-Katz technique) to 32 health workers from commune, district and provincial levels in Yen Bai and Thanh Hoa provinces. Improve research capacity for future parasitologists through the provision of full scholarships from project funding for 3 PhD students to study and protect successfully at their training institutions in Belgium (University of Liège-ULiège, Free University of Brussels-ULB), granting 6-month scholarships to 4 master's students to conduct research for dissertations and graduate with distinction in the Netherlands (University of Twente), Thailand (Kasetsart University) and Vietnam (University of Public Health).
The project organizes an annual Steering Committee with representatives from the World Health Organization (WHO) and the Belgian embassy to report on the achievements of the project.
Steering Committee meeting (Project members, PhD students, master's students, guests from WHO)
Dr. Bui Thi Dung shared that the integrated control model that the project has implemented (communication, biological control in animals, fish, snails, environment) needs to be widely deployed in other areas across the country. Biocontrol initially tested successfully in vitro, necessitating large-scale in vivo. The project has contributed new general data on the situation of fluke infection in humans, animals, fish, snails and the environment. This is a success in developing a sustainable integrated control strategy combining medicine, veterinary medicine, fisheries, biology, food science and anthropology-society, transferring new diagnostic techniques from Belgian experts (flukefinder technique), improving the ELISA technique to increase the accuracy of results. With the results achieved by the project, the research team wishes to apply the One Health integrated control model to many provinces and cities where there is transmission of pediculosis to humans through food.
Translated by Phuong Ha
Link to Vietnamese version