Two instances of the fatal Nipah virus in India have prompted authorities in Thailand and Malaysia to enhance airport screening measures to prevent the spread of the infection. But what exactly is the Nipah virus, and how concerned should the public be? Here are some insights.
India’s Health Ministry revealed on Tuesday that two cases of Nipah had been identified since December. All contacts of the patients were placed in quarantine and tested. While the ministry did not disclose details about the patients, it mentioned that 196 contacts were traced, all of whom tested negative.
“The situation is continuously being monitored, and all essential public health measures are in place,” stated the ministry.
No cases of the virus outside India have been reported, but several Asian nations have introduced or strengthened screening protocols at airports as a precautionary measure.
Nipah is a rare viral infection primarily transmitted from infected animals, particularly fruit bats, to humans. It can be asymptomatic but is often severe, with a case fatality rate ranging from 40 to 75 percent, depending on the local healthcare system’s detection and management capabilities, as per the World Health Organization.
Although person-to-person transmission is possible, it is not easily spread, and outbreaks are typically limited in size and containment, according to experts and the European Centre for Disease Prevention and Control. While candidate vaccines are in development, none have yet received approval.
Nipah was first identified in Malaysia in 1999, leading to small outbreaks almost every year, primarily in Bangladesh, with sporadic occurrences in India. As of December, the Coalition for Epidemic Preparedness Innovations reported 750 cases, resulting in 415 fatalities.
Initially spreading through direct contact with sick pigs or contaminated tissues in Malaysia, Nipah now mainly transmits through contact with its natural host, fruit bats. Consuming fruits or products like raw date palm juice contaminated with urine or saliva from infected fruit bats is identified as the primary mode of infection, according to WHO. Human-to-human transmission occurs primarily through close contact between a sick individual and their family or caregivers.
Symptoms of Nipah, such as fever, headaches, and muscle pain, are nonspecific and may mimic other illnesses. Neurological signs indicating acute encephalitis or brain inflammation may follow, along with severe respiratory issues. Severe cases may progress to seizures and coma, with most patients recovering fully, although some may experience long-term neurological complications.
Despite its high fatality rate, Nipah has not demonstrated increased transmissibility among humans or widespread global spread to date, according to scientists. Nevertheless, it remains a significant public health concern, particularly in regions with frequent outbreaks, potentially leading to the mass culling of susceptible farm animals like pigs.
Although global spread is unlikely, scientists caution that airport screening may be ineffective due to the virus’s extended incubation period.
Currently, there are no approved vaccines or treatments for Nipah. However, several candidates are undergoing testing, including one developed by Oxford University scientists involved in COVID-19 vaccine development. Their Nipah vaccine, utilizing similar technology, commenced Phase 2 trials in Bangladesh in December in partnership with the International Centre for Diarrhoeal Disease Research, Bangladesh, and with financial support from the Coalition for Emergency Preparedness Innovations.