Does biodiversity protect humans against infectious disease?

Area of Science:

• Disease Ecology
• Conservation Biology
• Public Health

Background:

• Biodiversity conservation is often framed as an ecosystem service that controls infectious diseases.
• Two proposed mechanisms for biodiversity loss increasing disease risk: increased competent hosts and loss of dilution effects.
• The dilution effect hypothesis suggests higher biodiversity lowers disease risk, a concept widely discussed in disease ecology.

Purpose of the Study:

• To evaluate the generality of the dilution effect across various human infectious disease agents.
• To assess the association between biodiversity and public health risks for a broad range of pathogens.

Main Methods:

• Review of existing literature and case studies on the relationship between biodiversity and infectious disease risk.
• Analysis of associations across diverse human disease agents and their transmission dynamics.

Main Results:

• The conditions for the dilution effect are unlikely to be met for most significant human diseases.
• Biodiversity has minimal net effect on the majority of human infectious diseases.
• When biodiversity does influence disease risk, it is more likely to increase than decrease it.

Conclusions:

• The dilution effect is not a universally applicable model for all infectious diseases.
• Elevated biodiversity may increase, rather than decrease, infectious disease risk for public health concerns.
• Conservation strategies must consider specific disease dynamics rather than assuming a general dilution effect.