Rare, New and Emerging Helminth Zoonoses

Abstract

This chapter deals with zoonotic species, which have been selected largely as being responsible for unrecognized helminth zoonoses or those, which although known to be zoonotic, have unexpectedly emerged as a major health hazard caused by social or other factors that have affected their epidemiology. Zoonoses are diseases and infections, which are naturally transmitted between vertebrate animals and man. At least 150 zoonoses have been recognized world-wide. Some “new” or “emerging” zoonoses have been man-made and are directly a result of unusual eating habits or a change in life style. In this group the rare but fatal infection with the trematode Alaria marcianae can be included with the trematode, which is acquired by eating raw frogs containing mesocercariae, and infection with the cestode Mesocestoides lineatus , which is acquired by eating raw chicken viscera. The most serious and widespread of the “emerging zoonoses” are caused by nematodes. The nematodes in this group, species of Angiostrongylus , Baylisascaris and, Oesophagostomum , have posed problems of diagnosis and have frequently been misdiagnosed in the past. The development of reliable seroimmunological tests is helping to resolve the diagnostic problems of these aberrant zoonoses, and while some progress is being made in this field much remains to be done.