Identifying Worm Species in Cows by Their DNA

Greg Howard
14th March, 2024

Identifying Worm Species in Cows by Their DNA

Image Source: Zülfü Demir (photographer)

Key Findings

  • Study in Côte d'Ivoire finds cattle infected only with Schistosoma bovis, not human-infecting hybrids
  • Schistosome parasites in cattle show low genetic diversity, suggesting inbreeding
  • Findings support a unified approach to schistosomiasis control for both humans and animals
Schistosomiasis, a disease caused by parasitic worms known as schistosomes, is a major public health concern, particularly in tropical and subtropical regions. While efforts to understand and control human schistosomiasis have been extensive, the impact of this disease on livestock, which can also be significant carriers of the parasite, has been less studied. A recent investigation by researchers from the Swiss Tropical and Public Health Institute[1] has taken a closer look at the prevalence and genetic diversity of schistosome infections in cattle within Côte d'Ivoire, a country where schistosomiasis remains a persistent problem. This study is pivotal as it fills a gap in our understanding of livestock schistosomiasis, which could be crucial for developing integrated approaches to disease control. The research team collected and analyzed 400 adult schistosomes from cattle at six different sites across Côte d'Ivoire, along with 114 miracidia, which are the larval form of the parasite, from live cattle at one northern site, Ferkessédougou. DNA analysis confirmed that all the parasites collected were Schistosoma bovis, a species known to infect cattle. This finding is consistent with previous work that reported a low prevalence of human schistosomiasis in northern Côte d'Ivoire[2], suggesting that S. bovis may be the predominant species in this region. Moreover, the study did not find any hybrids of Schistosoma haematobium (a species that typically infects humans) and S. bovis in the cattle sampled, which contrasts with other studies that have reported such hybrids in human populations in West Africa[3] and Cameroon[4]. The genetic diversity among the S. bovis populations was assessed using 12 microsatellite markers, which are specific DNA sequences that can be used to measure variability within a species. The results indicated a lack of genetic diversity, with signs of inbreeding among the schistosome populations across all the sites studied. This suggests that the S. bovis population in Ivorian cattle is relatively homogenous, with little genetic differentiation between different geographic regions. These findings have important implications for schistosomiasis control programs. The lack of genetic diversity and geographic structuring in S. bovis populations could mean that control measures effective in one area might be applicable across the country. However, the study's results also raise questions about the potential for S. bovis to spread and establish in new areas, including those where human schistosomiasis is prevalent. In light of these findings, the study emphasizes the need for a One Health approach to schistosomiasis surveillance and control. This would involve coordinated efforts to manage the disease in both human and animal populations. Such an approach is supported by recent advancements in molecular research techniques, such as the development of a duplex T-ARMS-PCR assay[5], which can differentiate between Schistosoma species and their hybrids. These techniques could be used to monitor schistosome populations more effectively and to understand the dynamics of transmission between humans and animals. Overall, the research conducted by the Swiss Tropical and Public Health Institute advances our knowledge of schistosome infections in cattle and underscores the importance of considering animal health in the broader context of human schistosomiasis control. It also highlights the need for continued surveillance and research to fully understand the epidemiology of this disease and to develop strategies that can mitigate its impact on public health and the economy in regions where it is endemic.

BiotechGeneticsAnimal Science

References

Main Study

1) Genetic characterization of schistosome species from cattle in Côte d'Ivoire.

Published 12th March, 2024

https://doi.org/10.1186/s13071-024-06221-9

Related Studies

2) Prevalence and risk factors of schistosomiasis and hookworm infection in seasonal transmission settings in northern Côte d'Ivoire: A cross-sectional study.

https://doi.org/10.1371/journal.pntd.0011487

3) Population genetic structure of Schistosoma haematobium and Schistosoma haematobium × Schistosoma bovis hybrids among school-aged children in Côte d'Ivoire.

https://doi.org/10.1051/parasite/2022023

4) Hybridization increases genetic diversity in Schistosoma haematobium populations infecting humans in Cameroon.

https://doi.org/10.1186/s40249-022-00958-0

5) A duplex tetra-primer ARMS-PCR assay to discriminate three species of the Schistosoma haematobium group: Schistosoma curassoni, S. bovis, S. haematobium and their hybrids.

https://doi.org/10.1186/s13071-023-05754-9


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