How can invasive species spread parasites and diseases in an ecosystem?

Invasive species can significantly disrupt ecosystems by acting as disease vectors, facilitating the spread of parasites and pathogens to native populations that may lack natural resistance.12

They typically spread these threats through the following mechanisms:

• Vector-borne transmission: Many invasive organisms, particularly insects, serve as biological or mechanical vectors. Biological vectors allow a pathogen to develop or replicate within them before transmitting it to a new host, while mechanical vectors passively carry infectious agents on their bodies, depositing them onto food or surfaces.34
• Introduction of novel pathogens: Invasive species often arrive in new habitats carrying microbes or parasites from their native ranges. When these are introduced to a new environment, they can cause widespread outbreaks among local species that have not evolved defenses against them.12
• Human-mediated transport: Global trade, travel, and the pet trade frequently transport invasive animals and plants alongside the parasites and pathogens they harbor, effectively bypassing natural geographic barriers.12

The ecological impact of these introductions is profound, often leading to population declines or the localized extinction of native species, further destabilizing the ecosystem.12