Why in News:
- Nipah virus antibodies (IgG antibodies) were detected in bat samples collected by the National Institute of Virology (NIV), from Kerala.
- Antibody, also called immunoglobulin, a protective protein produced by the immune system in response to the presence of a foreign substance
About Nipah Virus
- Nipah virus (NiV) is a ‘zoonotic’ virus, that is, it is transmitted to human beings from animals. The virus can also be transmitted through contaminated food, or directly between people.
- The pathogen that causes NiV encephalitis is an RNA virus of the family Paramyxoviridae, genus Henipavirus, and which is closely related to the Hendra virus (HeV).
- The animal host reservoir for both HeV and NiV is the fruit bat, which is commonly known as the ‘flying fox’. Fruit bats of the Pteropodidae family are the natural host of Nipah virus.
- In infected people, it causes a range of illnesses from asymptomatic (subclinical) infection to acute respiratory illness and fatal encephalitis. The virus can also cause severe disease in animals such as pigs, resulting in significant economic losses for farmers.
- The virus is present in urine, bat faeces, saliva, and birthing fluids of bats.
- Infected fruit bats can spread the disease to other animals as well, such as pigs — and also dogs, cats, goats, horses and sheep.
- Human beings can get infected if they come in close contact with the infected animal — bats or other animals such as pigs or its body fluids such as saliva or urine.
- The initial jump of the virus from animal to human is known as a ‘spillover’ event in an outbreak.
- Once the infection has moved to humans, person-to-person spread of NiV can occur.
- There is no treatment or vaccine available for either people or animals. The primary treatment for humans is supportive care.
- Nipah virus is on the WHO list of Blueprint priority diseases.
Nipah virus: symptoms
- NiV infection can cause a mild to severe disease, which in the latter situation sees a major swelling in the brain (encephalitis), and can lead to death.
- Symptoms of the infection can appear at any time from four days to two weeks after exposure to the virus. Patients usually report a fever and headache that can last from three days to a couple of weeks, accompanied by symptoms of respiratory illness such as cough, sore throat, and difficulty in breathing.
- If the disease progresses to encephalitis, the patient may experience drowsiness, disorientation, and mental confusion, which can then progress very quickly to a coma within 1-2 days.
- Between 40 percent and 75 percent of cases can lead to death, according to the World Health Organisation (WHO). However, the fatality rate in the 2018 outbreak in Kozhikode was well over 90 per cent.
- Those who have survived the disease have reported long-term side effects, among them persistent convulsions and, in some cases, changes in personality.
History of Nipah
- Nipah virus was first recognized in 1999 during an outbreak among pig farmers in Malaysia.
- It was also recognized in Bangladesh in 2001, and nearly annual outbreaks have occurred in that country since.
- In 2018, an outbreak of the disease caused deaths in Kerala.
- Bats are the largest mammalian group after rodents, with over 1,300 species making up a quarter of all mammals.
- The Indian Wildlife Protection Act of 1972 consigned bats to schedule V as ‘vermin’.
- They are the only mammals capable of true flight and have a unique sonar-based echolocation mechanism to capture prey at night.
- Bats are important pollinators and crop protectors, especially of large-flowered plants. Pollination of flowers, dispersal of seeds of trees, shrubs and climbers are all part of their function in the ecosystem.
- Insectivorous bats are ferocious hunters of nocturnal insects and crop pests, accounting for 70% of all bat species.
- Bat droppings contribute to soil fertility and agricultural output by providing organic input and facilitating nutrient transfer. In terms of human health, the practise is safe.
- Seed dispersal
- Tropical fruit bats play a significant role in rainforest ecosystems.
- Bat droppings in the caves they occupy support a delicate ecosystem composed of unusual organisms.
Some of the diseases spread by bats
- Severe Acute Respiratory Syndrome (SARS)