Nipah virus is a highly pathogenic, bat-borne virus first identified in 1998. It can cause severe respiratory illness and fatal brain inflammation (encephalitis) in humans and has a high case fatality rate, though it spreads poorly between people. The virus is not present in Australia, and there is currently no approved vaccine. Recent outbreaks in India have brought global attention back to Nipah, emphasizing its potential for small but serious outbreaks in affected regions.
Australian researchers at CSIRO are studying Nipah virus and related bat-borne pathogens to strengthen national preparedness and expand scientific understanding of emerging infectious diseases. CSIRO recently discovered a previously unknown virus in the same family as Nipah, highlighting the ongoing focus on high-consequence pathogens. Research activities include developing diagnostics, surveillance tools, early-stage vaccines and treatments, and conducting field studies both domestically and internationally.
Transmission of Nipah virus occurs mainly through direct contact with bodily secretions of infected bats or intermediate hosts such as pigs, as well as through contaminated food, like date palm sap. Human-to-human transmission can happen through close contact with infected individuals or exposure to their bodily fluids. Outbreaks are largely localized and effectively contained through existing public health measures, as the virus does not spread easily or via airborne routes.
Although Australia has no Nipah cases, related viruses such as Hendra virus exist in Australian flying foxes. Hendra can spill over from bats to horses and occasionally to humans, but there is no evidence of direct bat-to-human transmission. CSIRO studies these viruses under Biosafety Level 4 containment, the highest level of biocontainment, to safely investigate their behavior and potential treatments.
Bats can host many viruses that are deadly to humans without falling ill themselves. Their immune systems are uniquely adapted to avoid overreacting, suppressing inflammation that would otherwise cause disease in humans. Human activity, habitat loss, and closer contact with wildlife increase the risk of spillover events, highlighting the need for careful monitoring and ecological conservation.
CSIRO advises the public not to handle bats directly. In case of encountering sick or trapped bats, contacting wildlife rescue organizations is the safest course of action, as trained and vaccinated rescuers can handle the animals safely. This approach helps minimize the risk of exposure to viruses such as Nipah or the Australian bat lyssavirus.
