International travel with pets. Part II. The threat of foreign pathogens

This article reviews an assortment of foreign pathogens that have been intr oduced into the United States (or other countries) by the pets of unwitting owners. These pathogens may be rickettsiae, protozoans, schistosomes, dipt eran fly larvae, filarial parasites, ticks, fleas, or leeches. Each pathoge n is discussed according to geographic distribution, clinical presentation, diagnosis, treatment, and zoonotic potential. Protozoans such as Trypanoso ma evansi have been introduced from other countries by pets. Myiasis-produc ing dipteran fly larvae, such as Cochliomyia hominivorax. Chrysomyia bezzia na, Cordylobia anthropophaga, and Dermatobia hominis, have the potential fo r producing significant myiases in humans and animals in the United States. Rhipicephalus sanguineus is already native to the United States and North America; however, this tick is capable of transmitting a variety of serious foreign pathogens, especially Rickettsia conorii, the etiologic agent of t ick-borne typhus. Ixodes holocyclus, the scrub tick, produces the most seri ous form of tick paralysis and could easily become established in North Ame rica. Dirofilaria repens, a filarial parasite found in the subcutaneous tis sues of dogs in Africa and the Orient, is now a proven zoonosis. A hermaphr oditic nasal leech, Myxobdella annandalei, has been imported into Germany i n the nostrils of a dog returning from Nepal. Veterinarians must be able to recognize this wide variety of foreign pathogens. Part I of this three-par t presentation discussed issues pertinent to leaving and returning to U.S, territorial borders with pets. Parts II and III review foreign pathogens th at have been introduced into various countries by pets.