Division of Virology, Indian Veterinary Research Institute, Mukteswar-263138, India.
Abstracts of the papers presented at the International Conference of Indian Virological Society on “Emerging and Re-emerging viral Diseases of the Tropics and Subtropics” at Indian Agricultural Research Institute, New Delhi, India, December 11–14, 2007.
Vaccinia virus (VACV), the type species of the genus Orthopoxvirus (OPV) is a double-stranded DNA virus, belongs to the subfamily Chordopoxvirinae of the family Poxviridae. The causative agents of smallpox, VACV and Variola virus (VARV) are mutually immunogenic and a type species of Orthopoxvirus, cause only mild complications in humans. Therefore, the VACV was used as a smallpox vaccine world over under mass immunization program promoted by WHO, which lead to the variola eradication globally in 1979. Since then, no vaccination of human population has been carried out, however, vaccination has continued for at-risk laboratory workers, military personnel and others working with recombinant VACV or other non-variola orthopoxviruses (OPVs). There has now been a surge in the development of safer smallpox vaccines and, understanding of the biology of VACV, because of rise in bioterrorist threats globally, necessitating re-use of this vaccine in most vulnerable population, the emergence and re-emergence of vaccinia-like viruses (VLVs) in Brazil, buffalopox viruses (BPXV) in Egypt, Indonesia, India and its neighbouring countries like Nepal, Pakistan. Bioterror threat as-well-as emergence and re-emergence of VLVs constitute a concern as 50% of the population globally (40% in USA) <30 years are unvaccinated and most vulnerable for smallpox reemergence. Thus, the search for new generation safer smallpox vaccine entails review of biology of VLVs in the smallpox-free world. In this paper, we present occurrence of VLVs in the world with exhaustive discussion particularly emergence and re-emergence of these viruses in India and Brazil where VLVs are sufficiently studied.
