With its death toll on a rise and the death of the nurse at Perambra Taluk hospital Kerala, panic about Nipah Virus is knowing no bounds. With half-informed WhatsApp messages about Nipah already doing rounds, it is tough to distinguish fact from fiction. While we have already done an article on what exactly is Nipah Virus (read here), this one is solely going to focus on the way the virus spreads and how it can be controlled.
As per the fact sheet about Nipah Virus by the World Health Organization, following are certain facts about the spread of Nipah, quoted verbatim:
- Infected bats shed virus in their excretion and secretion such as saliva, urine, semen and excreta but they are symptomless carriers.
- The NiV is highly contagious among pigs, spread by coughing.
- Direct contact with infected pigs was identified as the predominant mode of transmission in humans when it was first recognized in a large outbreak in Malaysia in 1999.
- Drinking of fresh date palm sap, possibly contaminated by fruit bats (P. giganteus) during the winter season, may have been responsible for indirect transmission of Nipah Virus to humans
- There is circumstantial evidence of human-to-human transmission in India in 2001. During the outbreak in Siliguri, 33 health workers and hospital visitors became ill after exposure to patients hospitalized with Nipah Virus illness, suggesting nosocomial infection.
- During the Bangladesh outbreak the virus is suggested to have been transmitted either directly or indirectly from infected bats to humans.
- Human-to-human transmission of NiV has been reported in recent outbreaks demonstrating a risk of transmission of the virus from infected patients to healthcare workers through contact with infected secretions, excretions, blood or tissues.
HOW DID THE VIRUS SPREAD IN KERALA?
It is being reported that three people who died due to NiV in Kerala may have consumed mangoes bitten by fruit bats as infected mangoes were found in their houses.
SO, HOW EXACTLY CAN HUMANS PREVENT THEMSELVES?
If you live in a region which is on an alert due to NiV, you can help yourselves in the following ways:
Animal-to-human transmission prevention
Do not consume date palm sap as the chances of it being contaminated are very high. Fruit bats are very likely to visit the date palm trees and lick the sap.
Domestic animals can also be the carriers of NiV as fruit bats often drop partially eaten fruits which can be consumed by them. Try to keep them indoors and feed them yourself or if there's a chance of them being infected, keep distance from them and get them treated.
Don't climb trees where bats may have left their saliva or secretions.
Human-to-human transmission prevention
Epidemiological surveys have yet suggested that human-to-human transmission of NiV is not very common. However, it is possible to get infected with NiV if one gets in touch with the secretions of infected patients.
The primary carriers of NiV in humans are the respiratory secretions. If you are near anyone who has the infection and have the chance to breathe in their out-breath, you can get infected too. The risk gets very high is the patient has respiratory symptoms, such as coughing and sneezing. Because of the same reason, never share food, bed or be very close to a sneezing or coughing NiV patient. At any cost, one should not come in contact with the saliva of an infected person.
Now, what about the urine of infected humans? As per a study published in the Journal of Infection, NiV was isolated from the patients in the Malaysia outbreak and it was found that traces of NiV were present in urine as well, besides saliva and throat swabs. So, be cautious if you are sharing a washroom with an infected person.
WHY ARE BATS SUDDENLY TURNING DANGEROUS?
As per the WHO, “There is strong evidence that emergence of bat-related viral infection communicable to humans and animals has been attributed to the loss of natural habitats of bats. As the flying fox habitat is destroyed by human activity the bats get stressed and hungry, their immune system gets weaker, their virus load goes up and a lot of virus spills out in their urine and saliva.” This means that ultimately, what is at blame is human activity only.
VACCINATION FOR NiV?
The WHO states that a vaccine is being developed. The vaccine is a recombinant sub-unit formulation that has proven successful in cats. Canarypox vectored Nipah F and G vaccine has appeared promising for preventing infection in swine and also has potential as a vaccine for humans.