High prevalence of natural infection by the ruminant blood fluke Schistosoma spindale in the intermediate snail host Indoplanorbis exustus in Uttaradit, Northern Thailand

Research (Published online: 20-02-2024)

21. High prevalence of natural infection by the ruminant blood fluke Schistosoma spindale in the intermediate snail host Indoplanorbis exustus in Uttaradit, Northern Thailand

Chorpaka Phuangsri, and Ornampai Japa

Veterinary World, 17(2): 413-420

Chorpaka Phuangsri: Division of Microbiology and Parasitology, School of Medical Sciences, University of Phayao, Phayao, Thailand.

Ornampai Japa: Division of Microbiology and Parasitology, School of Medical Sciences, University of Phayao, Phayao, Thailand; Scientific Instrument and Product Standard Quality Inspection Center, University of Phayao, Phayao, Thailand.

doi: 10.14202/vetworld.2024.413-420

Article history: Received: 06-10-2023, Accepted: 29-01-2024, Published online: 20-02-2024

Corresponding author: Ornampai Japa

E-mail: ornampai.ja@up.ac.th

Citation: Phuangsri C, and Japa O (2024) High prevalence of natural infection by the ruminant blood fluke Schistosoma spindale in the intermediate snail host Indoplanorbis exustus in Uttaradit, Northern Thailand, Veterinary World, 17(2): 413–420.

Abstract

Background and Aim: Freshwater snails belonging to the family Planorbidae serve as the first intermediate hosts of many species of important parasitic flukes of animals and humans. Information regarding the occurrence of planorbid snail larval trematode infection is limited in Northern Thailand. Thus, this study aimed to estimate the prevalence of larval trematode infection of the freshwater snail Indoplanorbis exustus in Uttaradit, Thailand, and to identify trematode species based on their morphological and molecular characteristics.

Materials and Methods: Planorbid snail specimens were collected from a water reservoir in Uttaradit, Thailand, from June to August 2023. Snails were assessed for larval trematode infection through cercarial shedding and crushing methods. The released cercariae were preliminarily identified on the basis of their morphological characteristics. In addition, species identification of the detected cercariae was conducted using 28S ribosomal RNA and cytochrome c oxidase subunit 1 gene sequence analyses.

Results: The overall prevalence of cercarial infection was 61.5% (107/174) in planorbid snails in Uttaradit province. Two species of cercarial trematodes, Schistosoma spindale (106/174, 60.9%) and Artyfechinostomum malayanum (1/174, 0.6%), were identified using morphological and molecular analyses, of which S. spindale was the most abundant species. Our studied snails did not have mixed infection with more than two cercarial species.

Conclusion: Our findings reveal a remarkably high prevalence of S. spindale cercariae infecting planorbid snails in Uttaradit, indicating that humans and animals across the study area are at risk of infection. Our data may contribute to the development of effective strategies to control this zoonotic infectious disease.

Keywords: Artyfechinostomum malayanum, cercaria, cercarial dermatitis, Indoplanorbis exustus, Planorbid snails, Schistosoma spindale.

Highlights

The document is a research article about the high prevalence of natural infection by the ruminant blood fluke Schistosoma spindale in the intermediate snail host Indoplanorbis exustus in Uttaradit, Northern Thailand.

The prevalence of cercarial infection in planorbid snails in Uttaradit, Thailand was found to be 61.5%.

Two species of cercarial trematodes were identified: Schistosoma spindale (60.9%) and Artyfechinostomum malayanum (0.6%).

Schistosoma spindale is a major parasite that affects ruminants and can cause visceral schistosomiasis in livestock. It is also a source of human cercarial dermatitis.

The high prevalence of S. spindale cercariae in planorbid snails indicates a risk of infection for humans and animals in the study area.

Further research is needed to better understand the distribution and implications of other hosts, such as rodents, in the transmission of S. spindale.