Emergence of Protozoal Diseases Impacting Arctic Communities

Dr. Grigg will discuss parasites, particularly outbreaks of coccidian parasites that are increasingly emerging as threats to arctic marine wildlife and indigenous community health.  He has identified an Arctic invasion of new parasite genetic variants concomitant with population expansion of definitive hosts (e.g., felids and canids) near Arctic marine estuaries and human communities that are causing widespread exposure of people and marine wildlife to these pathogenic pollutagens. 

Waterborne outbreaks of coccidian parasites such as Toxoplasma gondii and Sarcocystis neurona, parasites that belong to the same major protist group as Plasmodium (the agent of malaria) are increasingly causing fatal disease in marine wildlife. Using population genetic and molecular methods to study the evolution, emergence and transmission of pathogenic strains of Toxoplasma and Sarcocystis parasites, our work has identified a marine invasion of new genetic variants produced when two parasites mate inside their definitive hosts (cats in the case of Toxoplasma, a wide variety of definitive hosts in the case of the genus Sarcocystis). Population expansions of definitive hosts near marine estuarine environments due to climate change and anthropogenic disturbance has led to increased deposition of highly infectious oocysts and widespread exposure of marine wildlife to these pathogenic pollutagens, particularly after storm events. Co-infection with both coccidian agents (i.e., polyparasitism) has been identified as a serious risk factor predisposing marine mammals to fatal infections