Bats: carriers of zoonotic viral and emerging infectious diseases

Bats are reported as reservoir host for several viruses, which cause significant illness in human and animals. Some of the bat transmitted zoonotic viral diseases such as Ebola, Hendra, Nipah and rabies may cause severe human casualties. They also harbor several other viruses such as MERS and SARS corona viruses, which may cause disease in human through direct spillover to human or through an intermediate host or vectors. Being reservoir hosts bats do not get affected by these viruses. This probably may happen due to the specificity of bat immune system, which reacts differently with viral pathogens in comparison to their other mammalian counterparts. Although bats are important reservoir hosts for several zoonotic viruses, very little information is available regarding host/virus relationships as only few experimental studies have been done on bat colonies, lack of expertise for study of bat immunology and antiviral responses and difficulty in conducting field work. However, with the advancement in epidemiology and molecular biology, these problems can be addressed, which will provide the insight into interactions of bats and zoonotic viruses. It may also clarify regarding virus persistence in nature and various associated risk factors which might facilitate viral transmission to animals and humans.