Bats in Nagaland can carry the Ebola virus family: study

NEW DELHI: Bats in some parts can harbor filovirus, a family of viruses that includes Marburg viruses and, which puts people who hunt them at risk for fatal diseases, according to a recent study.

Researchers, including Ian Mendenhall of Singapore, as well as pilot Dovih and Uma Ramakrishnan of the National Center for Biological Sciences in Bangalore, analyzed blood serum samples from bats hunted by people in the Mimi village of Nagaland.

The results of the study, published in PLOS Neglected Tropical Diseases on Thursday night, revealed that some bats sampled in the study may have been exposed to filovirus by finding antibodies (proteins reactive to specific parts of an infectious agent) in serum taken from the bats.

In the state of Nagaland, in northeastern India, local ethnic groups have made bat crops for at least seven generations as a source of food and traditional medicine. These bat hunters are exposed to the saliva, blood and excreta of the species of bats Rousettus leschenaultii and Eonycteris spelaea, the researchers wrote in the study.

The study calls for better community monitoring of bats in specific regions to prevent an epidemic outbreak in the future.

We report the presence of reactive antibodies of filovirus (eg, Ebolavirus, marburgvirus and dianlovirus) both in humans (eg bat hunters) and in bat populations of northeastern India, a region with no historical history of disease, the researchers wrote in the study.

They said that five of the 85 human serum samples taken from the villagers contained antibodies. This meant that there was evidence of immune reaction against three different filoviruses, they explained.

We have antibodies in bats that react against three different filovirus surface proteins - these are the part of the virus against which most antibodies are made, co-author of the study, Ian Mendenhall of Duke-National University of Singapore told PTI in an email interview.

One is probably the Mengla virus, described earlier this year from a site in China 800 kilometers away, and in one of the same species of bats in the harvest. The other two filoviruses are probably unknown, he added.

However, the researchers said they did not detect evidence of filovirus itself.

Mendenhall reasoned that this could be due to the fact that the sample size of the bat in the study is small, due to a weak presence of the virus in the serum or to the high genetic diversity of the family of filovirus that is not captured in the tests used .

It is unknown if these viruses are pathogenic or if they are present in bats without causing any symptoms, he added.

We continue our studies in this region to better understand your public health risk, he said.

The researchers said some factors prevent outbreaks of filovirus disease in Asia. These included ecological barriers that prevented the transmission of these viruses from animals to humans, the viruses could not maintain transmission between humans or the presence of diverse and closely related filoviruses that cause infection without symptoms in humans.

However, Mendenhall warned that any increase in contact between bats and humans can increase the risk of an infectious disease being transmitted to humans.

He said that this can happen through changes in the landscape where humans and bats coexist, which leads to increased interactions with humans, or by amplifying hosts such as cattle or other wildlife.

This was observed in SARS coronavirus outbreaks in Hong Kong and Guangdong Province, China, and in the Nipah virus outbreak in Malaysia in 1999, he told PTI.

The researchers warned that any contact that infected bats may have with wild animals provides an opportunity for these viruses to break through the species barrier and begin to infect new populations of animals, a phenomenon that researchers call an indirect infection.

However, Mendenhall said that the incidence of this is incredibly rare since one requires a virus that encounters a susceptible host (for example, a human-ecological barrier), is able to replicate in it (cell barrier, since it needs the correct cellular receptor), and needs to be transmitted from human to human (epidemiological barrier).

He said it is still unknown if there is an increased risk of spreading of filovirus in India, as there is no evidence of a past outbreak in South Asia and Southeast Asia.

It is known that the Ebola and Marburg viruses cause serious diseases that affect many organs and damage blood vessels, killing more than 50 percent of the people they infect.