PhD defence Vinh Hoang Quang

KEY FINDINGS

1. A systematic review identified documents that reported Fasciola spp. in seven out of 11 Southeast Asian countries. Most studies focused on infections in animals (72%) and humans (21%). Few studies reported on Fasciola infections in snails, and none on metacercariae on plant carriers. These findings indicate a significant gap in understanding the full lifecycle of Fasciola spp. transmission in Southeast Asia.

2. In north-central Vietnam, a high prevalence of Fasciola spp. was found in livestock (52% by copro-microscopy, 54% by antibody-ELISA), while infection in humans was very low (0.07% by antibody-ELISA). Larval stages of Fasciola were not found on water plants or in snails.

3. The study revealed low community awareness of fascioliasis, with 85% of respondents being unaware of the disease. Of those who were aware, only 9% could identify symptoms of fascioliasis. Risky behaviors, such as consuming raw vegetables (93%) and using untreated manure (67%) for fertilizing crop fields, were common, highlighting the need for targeted public health education to improve knowledge and promote safer practices.

CONCLUSIONS

This thesis underscores the need for a multifaceted approach to control fascioliasis in Vietnam, integrating human, animal, and environmental health strategies. Given the low prevalence of human infections observed in the study area, mass drug administration is not warranted. Instead, selective treatment, improved livestock management, and community education are key to reducing the disease's burden. The research calls for further multi-host studies covering all entities involved in the life cycle of Fasciola spp., including snails and water plants.