New and Emerging Parasitic Zoonoses

Abstract

The global burden of zoonotic parasites is huge but not well characterized and the annual human incidence or prevalence worldwide [not been calculated] is likely in the hundreds of millions. These parasites are widespread in wildlife, domestic animals used for food, and pets. Transmission of zoonotic parasites can be from the food chain, contamination of water/food through fecal/soil contamination, and insect vectors. Zoonotic parasites are not limited to tropical and subtropical regions but are also prevalent in the temperate hemisphere, and no country in the world is spared. Globalization of these uncommon conditions are facilitated by ease of international travel, large migration of refugees fleeing regional conflicts and wars, and change in dynamic interactions between arthropods and their hosts, including humans. These latter factors include climate change, urbanization and deforestation to change demo-graphics in developed and developing countries, impact of economic crisis, and increased movement of people and animals following major catastrophes [1]. This chapter will review existing parasitic zoonosis that rarely affected humans but has been emerging as a problem, such as sarcocystosis, and parasites that were considered only animal pathogens but have been increasingly recognized to infect humans, i.e., Baylisascaris procyonis, Dirofilaria species, Onchocerca lupi, and Trypanosoma species. See Table 11.1 for a summary of these conditions. 11.2 Baylisascariasis Baylisascariasis is a zoonotic infection caused by the raccoon roundworm, Baylisascaris procyonis [2]. Raccoons [Procyon lotor] are the definitive host and the adult worms live in the small intestine, where females pass embryonated eggs in the feces. The life cycle is maintained in young raccoons by the ingestion of embryonated