Veterinary Epidemiology and Zoonosis

ROLE OF WILD ANIMALS IN THE TRANSMISSION OF ZOONOTIC DISEASES 

• Wild animals are the known host to the wide range of different microorganisms.
• Wild animal diseases may be expressed as frank diseases or silent infection. But, many infections of man and domestic animals exist silently in wild animal species as infections which are not apparent.
• Many emerging and sylvatic zoonoses are being reported with increasing frequency in man and animals like the orphan viruses (enterovirus, myxovirus, herpesvirus).
• Infections present in wildlife form ‘enzootic foci’.
• Alteration in the environment for the human welfare such as construction of dams, canals, deforestation and tilling of the grass lands for agricultural development may enhance the chances of human contact with the foci of infection.
• Rats, mice, monkeys, bats, foxes, wolves, skunks, migratory water fowls, ducks involve with epidemiology of zoonotic diseases.
  • Examples
    • Monkeys: Deforestation in Shimoga district near Mysore (Karnataka), India resulted in the outbreaks of Kyasanur forest disease (KFD) in humans due to migration of carrier monkeys through an epidemiological cycle of ‘Monkey-Tick (Haemophilus spinigera)-Migratory birds’.
    • Arthropod-borne/tick-borne zoonoses: Monkeys are the reservoirs for yellow fever in humans, tick typhus (boutonneuse fever), Crimean haemorrhagic fever, Q-fever, tularaemia.
    • Migratory birds: Avian influenza, West Nile virus, EEE, WEE
    • Skunks, ferrets, bats, foxes, wild dogs and cats: Rabies