One Health implications and first evidence of environmental contamination of helminths in soil from goat farms in Ratchaburi, Thailand

Abstract

Zoonotic helminths are responsible for the majority of helminthic infections occurring in humans globally. Environmental systems serve as a reservoir for zoonotic helminths, facilitating their transmission to humans and animals. Livestock farms may serve as hotspots for zoonotic transmission, increasing infection risk. Focusing on goat farms in Ratchaburi Province, Thailand, we aim to detect and identify zoonotic helminths present in the soil environment through morphological and molecular techniques. Soil samples (n = 270) were collected from 30 goat farms in Ratchaburi Province, and helminths were morphologically identified using a modified sedimentation and flotation method. Helminths were then molecularly identified using the nuclear 18S rRNA gene and the internal transcribed spacer 2 region. The helminths identified include human, livestock-parasitic nematodes, trematodes, cestodes, plant-parasitic nematodes, insect-parasitic nematodes, and free-living nematodes. Morphological and molecular detection show that 80% and 86% of the farms were positive for helminths, respectively. From 30 farms, 60% were positive for livestock- or human-parasitic helminths, with eight species detected. Moreover, 50% of farms were positive for either Haemonchus contortus or Trichostrongylus colubriformis. Utilizing soil as a non-invasive method for the detection and identification of helminths contaminated in the soil, this study demonstrated the presence of human- and animal-parasitic helminths with the soil matrix serving as a shared environment and reservoir for zoonotic transmission of helminthic infection, further emphasizing the importance of the One Health approach towards mitigating parasitic disease transmission. The findings showed significant implications for the incorporation of soil-based methods into sustainable helminth infection control programs.

Keywords: Goat; One Health; Soil; Thailand; Zoonotic helminths.

Fig. 1

Map showing the districts where soils from goat farms were obtained

Fig. 2

Percentage of soil samples positive for helminths per district

Fig. 3

Maximum likelihood phylogeny for nematodes using the nuclear 18S rRNA gene (T3 + G). Numbers at nodes indicate bootstrap values (ML/NJ). Only bootstrap values of > 70 are shown. Representative sequences from this study are indicated with an asterisk, “*”. The human- or livestock-parasitic nematodes are indicated in “red” text

Fig. 4

Maximum likelihood phylogeny for Trichostrongylidae using the nuclear ITS2 region (K2). Numbers at nodes indicate bootstrap values (ML/NJ). Only bootstrap values of > 70 are shown. Representative sequences from this study are indicated with an “*”

Fig. 5

Maximum likelihood phylogeny for trematodes using the nuclear 18S rRNA gene (K2). Numbers at nodes indicate bootstrap values (ML/NJ). Only bootstrap values of > 70 are shown. Representative sequences from this study are indicated with an “*”

Fig. 6

Maximum likelihood phylogeny for cestodes using the nuclear 18S rRNA gene (K2 + G). Numbers at nodes indicate bootstrap values (ML/NJ). Only bootstrap values of > 70 are shown. The representative sequence from this study is indicated with an “*”