Division of Virology, Indian Veterinary Research Institute, Mukteswar, Nainital Districts, Uttaranchal-263138.
Abstracts of the papers presented at the 16th Annual Convention and International Symposium of Indian Virological Society on “Management of Vector-Borne Viruses” at International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru-502324, Hyderabad, India, February 7–10, 2006.
Emerging infectious diseases (EIDs) can be defined as diseases that have recently increased in incidence or geographic range, recently moved into new host populations, recently been discovered or caused by newly evolved pathogens. The line between human and animal pathogens has become finer in the past few years. There has been tremendous increase in number of zoonotic diseases that affect both humans and animals. Notable among them are Hantavirus diseases, Lyme borreliosis, Hendra, Nipah, and West Nile viral diseases, monkeypox (via black tailed prairie dogs [Cynomys ludovicianus], avian influenza, and the coronavirus, severe acute respiratory syndrome (SARS). RNA viruses have high mutation rates (RNA polymerase lacks proof-reading activity) and therefore have more potential to emerge and re-emerge. Quasi-species have been reported for many RNA viruses, which allow considerable plasticity within the viral population for adaptation in a harsh new environment of a new host, selective pressure of the host immune system or antiviral drugs. The influenza epidemics or annual outbreaks of foot and mouth disease (FMD) in animals result due to antigenic drift resulting in appearance of a new variant. A zoonotic disease in pig workers in 1998 in Malaysia was attributed to the Nipah virus, a member of family Paramyxoviridae, subfamily Paramyxovirus. Hendra virus is closely related to Nipah virus (approx. 78% N gene sequence homology) is fatal to horses and humans, under experimental conditions. Hendra virus may infect cats and guinea pigs. The sensitivity of a passive surveillance system is always a concern. In general, any system will find large outbreaks but finding smaller outbreaks or scattered cases of disease is the real challenge warranting effective disease surveillance employing highly sensitive and specific assays.
