Nipah/Hendra Virus & Fruit Bat Home Range – WHO
# 6098
Last summer the movie `Contagion’ showed the world how a bat virus might mutate, evolve, and eventually move into the human population. While the movie used a fictionalized MEV-1 virus, it was based on the all-too-real Nipah Virus, which first came to prominence in the 1990s after a deadly outbreak in Malaysia in 1998.
While human infections with Nipah (or its Australian cousin Hendra) have been relatively uncommon, when they have occurred they have proven particularly lethal, with fatality rates pushing 60%.
During the Malaysian outbreak in 1998, the virus jumped to local swine herds from bats, and along with infecting hundreds of people caused the loss over 100 lives. The virus was then exported via live pigs to Singapore, where 11 more people died.
Over the past decade, Nipah has sparked a number of small outbreaks across Southern Asia, although the most intense activity has been centered around Bangladesh.
Over the past 48 hours we’ve seen some reports coming out of Bangladesh indicating that several people have been infected with the Nipah virus. Nipah reports out of this region typically come between December and May.
Today, the IEDCR issued the following statement, indicating there have been 5 fatalities thus far.
Nipah Outbreak at Joypurhat in January 2012
From 20 January 2012, two clusters of Nipah were identified in the Joypurhat Municipality area and Khetlal upazila of Joypurhat district. A joint team of IEDCR and ICDDR,B are working in the field now.
Till date (23 rd January 2012), the team identified 3 cases from the municipal area and 2 cases from Khetlal. All 5 cases have died. Laboratory tests for Nipah were done in IEDCR. All four samples collected from suspected cases were positive for Nipah.
Map Credit- Wikipedia
CIDRAP has a nicely done Overview of the Nipah Virus including the clinical symptom chart below:
Exactly how the Nipah virus is transmitted from human-to-human isn’t well understood, although it is thought to be mostly through direct contact with respiratory secretions or other bodily fluids.
For now - while Human-to-human transmission has been documented - only limited outbreaks have been reported.
Last February, in Bangladesh: Updating The Nipah Outbreak I wrote about a couple of EID Journal studies that looked at Nipah transmission between humans.
The World Health Organization has this to say about the human-to-human transmission of the Nipah Virus.
Transmission
During the initial outbreaks in Malaysia and Singapore, most human infections resulted from direct contact with sick pigs or their contaminated tissues. Transmission is thought to have occurred via respiratory droplets, contact with throat or nasal secretions from the pigs, or contact with the tissue of a sick animal.
In the Bangladesh and India outbreaks, consumption of fruits or fruit products (e.g. raw date palm juice) contaminated with urine or saliva from infected fruit bats was the most likely source of infection.
During the later outbreaks in Bangladesh and India, Nipah virus spread directly from human-to-human through close contact with people's secretions and excretions. In Siliguri, India, transmission of the virus was also reported within a health-care setting, where 75% of cases occurred among hospital staff or visitors. From 2001 to 2008, around half of reported cases in Bangladesh were due to human-to-human transmission.
Reducing the risk of infection in people
In the absence of a vaccine, the only way to reduce infection in people is by raising awareness of the risk factors and educating people about the measures they can take to reduce exposure to the virus.
Public health educational messages should focus on the following.
- Reducing the risk of bat-to-human transmission. Efforts to prevent transmission should first focus on decreasing bat access to date palm sap. Freshly collected date palm juice should also be boiled and fruits should be thoroughly washed and peeled before consumption.
- Reducing the risk of human-to-human transmission. Close physical contact with Nipah virus-infected people should be avoided. Gloves and protective equipment should be worn when taking care of ill people. Regular hand washing should be carried out after caring for or visiting sick people.
- Reducing the risk of animal-to-human transmission. Gloves and other protective clothing should be worn while handling sick animals or their tissues, and during slaughtering and culling procedures.
While the Nipah Virus may not pose anywhere near as great of a threat to the world as a pandemic influenza, it does point out the need for increased surveillance and improved public health programs around the world.
