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. 2022 Jan 10;106(3):809-817.
doi: 10.4269/ajtmh.21-0038.

Effects of Environmental Factors and Infecting Trematodes on the Size and Inorganic Elements of Bithynia siamensis goniomphalos Snails in Northeast Thailand

Yi-Chen Wang  1 , Siew Ping Yeo  1 , Jutamas Namsanor  1   2 , Paiboon Sithithaworn  2   3 , Shuhan Yang  1
Affiliations

Effects of Environmental Factors and Infecting Trematodes on the Size and Inorganic Elements of Bithynia siamensis goniomphalos Snails in Northeast Thailand

Yi-Chen Wang et al. Am J Trop Med Hyg. .

Abstract

Infection with the foodborne trematode, Opisthorchis viverrini, is a major public health issue in southeast Asia. The freshwater snail, Bithynia siamensis goniomphalos, is an intermediate host of O. viverrini and other trematode species. Understanding the effects of environmental conditions and infecting trematodes on B.s. goniomphalos snails is thus crucial for the potential influences on trematode transmission. This study measured environmental variables of water and soil properties, and analyzed B.s. goniomphalos snails for their trematode infection, snail shell length, and inorganic elemental concentration, from 30 localities in northeast Thailand. The results showed that prevalence of trematode infection in B.s. goniomphalos was 3.82%. Nine types of trematode cercariae were identified, with virgulate type 1 as the most common (1.23%). Opisthorchis viverrini-infected snails were mostly found in low-humic gley soils in Sakon Nakhon Province, and were associated with water dissolved oxygen and soil pH. Compared with uninfected snails, larger sizes were observed in virgulate type 1 and pleurolophocerca-infected snails, whereas hypercalcification was noticed in virgulate type 1, virgulate type 3, and pleurolophocerca-infected snails. Infected snails were more sensitive toward environmental conditions, possibly because of the dynamic parasitic processes between trematodes and hosts. Among the environmental factors, soil texture (i.e., sand, silt, and clay compositions) exhibited more significant correlations with B.s. goniomphalos shell characteristics regardless of the trematode infection types. The findings of this study underscore the need to consider the effects of environmental conditions and trematode species-specific pathogenic processes for a more effective and sustainable parasitic control and prevention effort.

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Figures

Figure 1.
Figure 1.
Mean sizes (mm) of uninfected snails and snails infected with different types of trematodes (* denotes statistically different in size at P = 0.05). The numbers at the bottom of the bars indicate number of snails analyzed.
Figure 2.
Figure 2.
Elemental concentrations of (A) Ca; (B) K, Mn, and Na; and (C) Cd, Cu, Ni, Pb, and Zn in Bithynia siamensis goniomphalos shells. The symbol * indicates significant difference between infected and uninfected snails, and the symbol ^ shows significant differences between O. viverrini-infected snails and other groups of snails (P = 0.05). N indicates number of snails tested.
Figure 3.
Figure 3.
Principal component analysis (PCA) biplot illustrating the variation of snails in different infection groups across environmental factors and snail characteristics. Arrows represent environmental factors and snail physical and chemical characteristics; point symbols represent snails of different infection groups with ellipsoids showing 95% confidence level. This figure appears in color at www.ajtmh.org.
See this image and copyright information in PMC

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References

    1. Sithithaworn P Andrews RH Nguyen VD Wongsaroj T Sinuon M Odermatt P Nawa Y Liang S Brindley PJ Sripa B , 2012. The current status of opisthorchiasis and clonorchiasis in the Mekong Basin. Parasitol Int 61: 10–16. - PMC - PubMed
    1. Sripa B Bethony JM Sithithaworn P Kaewkes S Mairiang E Loukas A Mulvenna J Laha T Hotez PJ Brindley PJ , 2012. Opisthorchiasis and Opisthorchis-associated cholangiocarcinoma in Thailand and Laos. Acta Trop 120: 158–168. - PMC - PubMed
    1. International Agency for Research on Cancer (IARC) , 2012. Biological agents. A review of human carcinogens. IARC monographs on the evaluation of carcinogenic risks to humans/World Health Organization. International Agency Research on Cancer 100B: 1–441. - PMC - PubMed
    1. Andrews RH Sithithaworn P Petney TN , 2008. Opisthorchis viverrini: an underestimated parasite in world health. Trends Parasitol 24: 497–501. - PMC - PubMed
    1. Petney T Sithithaworn P Andrews R Kiatsopit N Tesana S Grundy-Warr C Ziegler A , 2012. The ecology of the Bithynia first intermediate hosts of Opisthorchis viverrini. Parasitol Int 61: 38–45. - PubMed

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