Understanding How Host Interactions Affect Disease and Biodiversity

Jim Crocker
5th May, 2024

Understanding How Host Interactions Affect Disease and Biodiversity

Glossary of network node metrics and definition of the types of species considered in this study.

Image adapted from: Barroso et al. / CC BY (Source)

Key Findings

  • In Spain, higher biodiversity slightly reduces disease risk, challenging the belief that more species always increase disease spread
  • Areas with low biodiversity and high wild boar centrality or livestock presence show the highest risk for multiple pathogen exposure
  • The study suggests that promoting biodiversity can be crucial for disease control in wildlife management and agricultural practices
Understanding the complex interplay between wildlife, livestock, and infectious diseases is crucial for both conservation efforts and agricultural management. A recent study by researchers at the University of Leon[1] has shed new light on this relationship by using camera-trapping-based social network analysis (SNA) to examine how biodiversity influences disease risk in Spain. The study focused on a range of vertebrate species captured on camera traps, with the number of species at each site varying from 10 to 33. Researchers assessed the diversity of these communities using the Shannon index, a mathematical formula that takes into account both the number of species and the evenness of their distribution. The values obtained ranged from 0.57 to 2.55, indicating varying levels of biodiversity across the study sites. One of the key findings was that at the community level, a marginal dilution effect was observed. This means that higher host diversity was slightly linked to a lower risk of disease, contradicting the idea that more biodiversity always increases the risk of disease transmission. In fact, the study found that the risk of exposure to multiple pathogens was negatively associated with the apparent diversity of host species. However, the relationship between biodiversity and disease risk is not straightforward. The study revealed that the highest risk of co-exposure to pathogens occurred in areas with the lowest rates of apparent biodiversity, especially when these areas also had high centrality of wild boars within the host community or the presence of livestock. Central species, like wild boars, play a significant role in the maintenance and transmission of pathogens within their communities. This study builds upon previous research that has explored the interactions between wildlife, livestock, and disease transmission. For example, a study in Doñana National Park, Spain[2], found that the spatial overlap between cattle and wild boar was a significant factor in the transmission of bovine tuberculosis (TB). The latest research expands on this by using SNA to identify key species and their role in pathogen spread within diverse animal communities. Moreover, the use of unmanned aircraft systems (UAS) in earlier studies[3] provided valuable data on the distribution and abundance of hosts, which is essential for understanding the determinants of disease transmission. The current study complements these findings by incorporating the centrality of species in the network, which could help in identifying hotspots for disease transmission. The debate over whether biodiversity has a dilution or amplification effect on disease risk is further complicated by the results of another previous study[4], which suggested that in Mediterranean Spain, ungulate host species richness correlates with increased community competence to maintain and transmit TB pathogens. The latest research suggests that this relationship is nuanced and influenced by environmental factors and the specific characteristics of the host community. The implications of these findings are significant for wildlife management and disease control strategies. By understanding the conditions that lead to the highest confluence of pathogens, such as lower apparent diversity indexes and higher relative abundances of species like the wild boar, managers can design more effective interventions. These might include targeted actions to reduce interactions between key wildlife species and livestock, as suggested by the Doñana National Park study[2], or prioritizing control measures in areas identified as high-risk through SNA. In conclusion, the study from the University of Leon highlights the complexity of the diversity-disease relationship and underscores the importance of considering multiple factors, including species centrality and environmental characteristics, when assessing disease risk. This nuanced understanding can lead to more targeted and effective disease prevention strategies, benefiting conservation, agriculture, and public health.

HealthEcologyEvolution

References

Main Study

1) New insights into biodiversity-disease relationships: the importance of the host community network characterization

Published 4th May, 2024

https://doi.org/10.1007/s10344-024-01799-y

Related Studies

2) Spatiotemporal interactions between wild boar and cattle: implications for cross-species disease transmission.

https://doi.org/10.1186/s13567-014-0122-7

3) Unmanned aircraft systems for studying spatial abundance of ungulates: relevance to spatial epidemiology.

https://doi.org/10.1371/journal.pone.0115608

4) Host Richness Increases Tuberculosis Disease Risk in Game-Managed Areas.

https://doi.org/10.3390/microorganisms7060182


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