SCIENTISTS have raised “urgent concerns” over new viruses discovered in bats which have the potential to spill over into humans and could be “highly fatal”.
Testing bats in China, experts found 22 viruses – 20 of which have never been seen before.
Two of the new viruses were close relatives of Nipah and Hendra viruses[/caption]
Two of these new bugs were of particular concern, as they were closely related to the deadly Nipah and Hendra viruses.
Both viruses can cause brain inflammation and dangerous respiratory disease in humans.
Nipah is a bat-bourne virus that’s been flagged as a “priority pathogen” by the World Health Organization (WHO) because of its potential to trigger an epidemic.
It can kill up to 70 per cent of its victims, with outbreaks reported in Bangladesh, India, Malaysia, the Philippines, and Singapore.
Meanwhile, Hendra is a rare virus that can spread to humans from horses that have been infected by disease-carrying bats.
Only seven cases have been reported in people, in Australia.
Scientists at the Yunnan Institute of Endemic Disease Control and Prevention detected two worrying viruses – described as the “evolutionary cousins” of Nipah and Hendra – while testing the kidneys of bats in the Yunnan province of China.
The bats lived in orchards close to villages, sparking concerns that fruit eaten by inhabitants and livestock may get contaminated and risk wider transmission.
“Bats have been implicated in a number of major emerging disease outbreaks, including Hendra, Nipah, Marburg and Ebola virus disease, severe and acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS) and Covid-19,” researchers wrote in the journal PLOS Pathogens.
“Bat-borne viruses are transmitted to humans either through direct contact with bats or via the ingestion of food or water contaminated with bat saliva, faeces, or urine.”
The study team – led by Dr Yun Feng – pointed out that previous research looking at the disease spreading potential of bats has only focused on their faeces.
But they said bugs living in bats’ kidneys also “present potential transmission risks” as they may be excreted through urine.
“The kidney can harbour important zoonotic pathogens, including the highly pathogenic Hendra and Nipah viruses,” scientists said.
They looked inside the kidneys of 142 bats from ten species, which were collected over four years in five areas of the Yunnan province.
Using advanced genetic sequencing, the team found 22 viruses, 20 of them never seen before.
Two of the most concerning were new henipaviruses, which are in the same group as Nipah and Hendra bugs.
The henipaviruses were found in fruit bats living near orchards close to villages.
Scientists said their study “rais[ed] urgent concerns about the potential for these viruses to spill over into humans or livestock.”
What is Nipah virus?
Nipah is a serious, and sometimes deadly, viral disease.
It’s carried by fruit bats which can be passed onto people.
Some patients present no symptoms while others present with severe inflammation of the brain.
Symptoms include fever, and headache followed by drowsiness and mental confusion.
About half of patients with neurological symptoms also experienced respiratory difficulty.
Progression of symptoms
People with Nipah usually start getting sick between four and 14 days after they were infected with the virus.
They are typically sick for three to 14 days with fever, headache, cough, sore throat, and difficulty breathing.
Later in the infection, some people may experience brain swelling, or encephalitis, where severe symptoms can include confusion, drowsiness, and seizures.
People with these symptoms can fall into a coma within 24 to 48 hours.
How it spreads
- Nipah virus can be transmitted from bats to humans through contact with infected bat secretions – for example by consuming raw date palm sap
- The virus can also spread to domestic animals, notably pigs, and cause disease in these populations
- NiV can also be transmitted through close contact with infected patients
How to prevent it
If you travel to or live in an area where Nipah virus outbreaks have occurred, you should:
- Wash your hands regularly with soap and water
- Avoid contact with flying fox bats or sick pigs
- Avoid areas where bats roost or
- Avoid touching anything that could be soiled by bats
- Avoid eating raw date palm sap or fruit that could be soiled by bats
- Avoid contact with the blood or body fluids of someone with Nipah
How it is treated
Treatment is currently limited to supportive care.
A vaccine has been developed to protect horses and this holds promise for future henipavirus protection for humans
Source: Centers for Disease Control and Prevention
Dr Alison Peel, a veterinarian and wildlife disease ecologist from the Sydney School of Veterinary Science at The University of Sydney, said: “The main significance of this work lies in the discovery of viruses in bats in China that are ‘evolutionary cousins’ to two of the most concerning pathogens in humans – Hendra virus and Nipah virus – which circulate in bats and are highly fatal if they spill over into people.”
But she said the viruses require further study before we can definitively state that they can pass on from bats to people.
“While one of the new viruses in this study appears to be the closest known relative to these highly fatal viruses, there are some genetic differences in the regions of the virus responsible for binding to and entering cells, so we can’t automatically assume that it can cross over to new species.
“We have other examples of close evolutionary cousins to Hendra and Nipah that appear not to be of any concern for spillover, so there will need to be some more laboratory studies on these new viruses to determine the actual risk.
Dr Peel went on: “Importantly, the bats infected with the Hendra-like virus were captured in fruit orchards, highlighting potential opportunities for contact with humans and domestic species.
“Our research on Hendra virus spillover in Australia has demonstrated clear links between habitat destruction, loss of natural food, and increased spillover risk – so this may also be the case in China.
“Rather than focusing on bats as the problem, we’ve also shown evidence that protecting and restoring bat food sources is an effective and sustainable solution.”
What is Hendra virus?
Hendra disease is an extremely rare illness caused by the Hendra virus.
Hendra virus was first identified during a 1994 outbreak of lung and brain disease in horses and people in Hendra, Australia.
The virus is part of the same virus family as Nipah virus.
Flying fox bats can infect horses with the virus when they bite the horses. Horses can also be infected if they are exposed to the urine, droppings, or saliva of an infected bat.
Hendra infections in people remain rare; only seven cases have ever been reported.
Progression of symptoms
Symptoms in people typically begin nine and 16 days after they had contact with an infected horse.
Hendra infection can cause lung problems with severe flu-like symptoms. In some cases, illness may progress to brain swelling.
Hendra infections are rare. However, it leads to death in more than half of people who get it (57 per cent).
Source: Centers for Disease Control and Prevention
