Characteristics of Hendra and Nipah Virus Infections

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In 1994 in Australia in Hendra suburb of the city of Brisbane the deadly outbreak of zoonotic influenza-like disease was primarily registered in horses that, in turn, infected contact humans with lethal outcomes. The causative agent was identified as a new parainfluenza virus (Hendra virus).

Likewise, in 1998-1999 in Malaysia in the village of Nipah a novel zoonotic parainfluenza virus was isolated after the severe animal outbreak that also affected humans with high lethality (Nipah virus).

Further outbreaks of Hendra and Nipah infections were repeatedly registered in Australia and Southeast Asia countries (Bangladesh, India, Malaysia, and Singapore).

Zoonotic Hendra and Nipah parainfluenza viruses appeared to be highly pathogenic for humans. The primary sources and natural reservoirs of infections are the fruit bats that spread the viruses to other animals or humans. The diseases are contracted via the direct contact with infected animals or fomites; aerosol or oral transmission is also taken into account.

In humans Hendra and Nipah infections are manifested as systemic viral disorders with encephalitis and severe pneumonia with acute respiratory failure. The lethality of disease outbreaks is very high in the range 40-60%.

Laboratory diagnosis of infections is based on molecular genetic methods (PCR) and serological testing (ELISA).

Human specific prophylaxis and treatment of these infections are not elaborated yet. In Australia the horses are immunized with vaccine against Hendra infection; experimental human Nipah vaccine is under clinical trial now.