Subsequent surveys carried out by the National Institute of Virology. Pune indicated that about half the population in South India had neutralizing antibodies of this virus. The disease is transmitted to man by the bite of infected mosquitoes. Man to man transmission has not so far been recorded. Before we see how the disease is transmitted let us look at some of the factors that enable the virus to replicate and survive to cause disease.
Animals are the major hosts for the virus.
Among them pigs are the most common. Cows, buffaloes and goats may also be affected by the virus but do not harbor the virus as a host. It has been postulated that certain birds may also act as the major hosts of the virus like the herons and the egrets. Among the animal hosts, pigs have been incriminated as the major vertebrate hosts for JE virus. The rice fields are probably the most important breeding places.