According to some scientists, global warming is anticipated to be accompanied by altered patterns of precipitation, changes in the frequency and intensity of extreme weather events, and continued species extinction. In the face of these events, pathogenic microscopic organisms appear to be on a mission to impact the surviving species. Bacteria, viruses, fungi, and parasites are rapidly adapting to–and in some cases, thriving in–Earth's changing environment.

Pathogenic microorganisms pose an important health threat to our horses as new diseases invade North America and previously eradicated diseases reappear.

"By definition, an emerging (infectious) disease is an infectious disease that has newly appeared in a population, and a re-emerging disease is one that has been known for some time but the number of cases is rapidly increasing in a certain population or geographic range," explains Scott Weese, DVM, DVSc, Dipl. ACVIM, an associate professor at the University of Guelph's Ontario Veterinary College