Editorial: Zoonotic Diseases

Abstract

Zoonotic diseases (zoonoses) are infectious diseases of vertebrate animals that can be transmitted to humans. The causative agents are bacteria, fungi, protozoan parasitesand viruses. Typical examples are anthrax, leptospirosis, bovine spongiform encephalopathy (BSE, mad cow disease), brucellosis, bovine tuberculosis, bubonic plague, taeniasis, trypanosomiasis, viral haemorrhagic fevers, rabies and influenza. It is thought that many modern epidemic diseases started out as zoonoses. This possibility is supported by evidence based on DNA and RNA sequencing. These include diseases such as measles, smallpox, human immunodeficiency virus (HIV) and diphtheria. Many types of "common cold" and tuberculosis are adaptations of strains originating from other animal species. Similarly, swine flu (H1N1) and avian flu (H5N1) have spilled over to human population even though on a limited scale. An observation by Dr. Jenner in 1798 that dairy workers exposed to cows infected by cowpox were immune to smallpox supports this theory. The HIV-1 that causes acquired immune deficiency syndrome is related to simian immunodeficiency virus found in chimpanzees. A brief description of some of the notable zoonotic diseases follows.