Zoonotic Infections
Overview
Zoonotic infections (also called zoonoses or anthropozoonotic infections) are human diseases acquired from a vertebrate animal. As a matter of fact, all arthropod-borne diseases with an animal host belong to the group of zoonotic infections, whether yellow fever, West Nile fever, Japanese encephalitis, tick-borne encephalitis or Rift Valley fever, to only name a few. Zoonotic infections also include haemorragic fevers such as EBOLA or Marburg, which primarily infect bats and secondarily African apes, Lassa fever and South American haemorragic fevers due to arenaviruses, which affect specific rodents, Nipah viral encephalitis, which is harbored in bats and may cause a lethal bronchopneumonia in pigs, as well as avian influenza (H5N1). They also include SARS, leptospirosis, plague, anthrax, and many other parasitic, viral and bacterial zoonoses. Several of these diseases are newly emerged and the general perception of their public health significance extends far beyond their actual incidence, due to their extremely high case fatality rate (60% for avian influenza, 50% for Nipah, 50% to 90% for EBOLA outbreaks). Many zoonotic infections actually are promoted by human behavior such as bush-meat hunting (EBOLA fever), the farming and trade of live wild animals (SARS), close and repeated contacts with infected animals (avian influenza), deforestation, which brings humans closer to infected vectors and animal reservoirs (leishmaniasis), or building of dams, that favors the proliferation of mosquitoes (Rift Valley fever). It is probable that bush-meat hunting was at the origin of HIV/AIDS
[1]
[2]. Rabies remains a major public health problem in the world's poorest areas, especially in Africa and South and South-East Asia, where most human cases follow stray dog bites.
This chapter will focus on rabies, anthrax, whose interest was renewed when used as a bioterrorism agent, plague, and hepatitis E, an acute viral hepatitis with a high case fatality rate in pregnant women whose most likely reservoir is pigs. Rift Valley Fever is another zoonotic infection with an important, albeit geographically limited, impact.