Terrestrial Pathogen Pollutant, Toxoplasma gondii, Threatens Hawaiian Monk Seals (Neomonachus schauinslandi) Following Heavy Runoff Events Journal of Wildlife Diseases
April 25, 2023
To understand environmental factors influencing Hawaiian monk seal exposure to Toxoplasma gondii, we examined monk seal strandings from toxoplasmosis in relationship to location and rainfall patterns throughout the main Hawaiian Islands.
Toxoplasmosis is a major threat to Hawaiian monk seals (Neomonachus schauinslandi) in the main Hawaiian Islands where seal habitat overlaps with substantial human and domestic cat populations. As the definitive hosts, members of the Felidae are the sole sources contaminating the environment with infectious oocysts; these oocysts can be transported into the marine environment, thereby threatening marine mammals.
We found that cases were up to 25 times more likely than controls to occur after heavy runoff events. The greatest odds ratio was observed when rainfall occurred 3 wk before strandings, potentially indicating important timelines in the disease process. Our results suggest that heavy rainfall frequently delivers sufficient numbers of oocysts to infect Hawaiian monk seals. With infectious doses of as low as a single oocyst, any contaminated runoff constitutes a risk to Hawaii's endangered monk seal.
Robinson SJ, Amlin A, Barbieri MM 2023. Terrestrial Pathogen Pollutant, Toxoplasma gondii, Threatens Hawaiian Monk Seals (Neomonachus schauinslandi) Following Heavy Runoff Events Journal of Wildlife Diseases 59(1), 1-11.
https://doi.org/10.7589/JWD-D-21-00179