The leeches hold the 'key' to prevent future corona virus outbreaks

A new way of monitoring wildlife can be an effective tool to prevent future diseases - starting with the operation of leeches to draw blood.

Using the latest biotechnology, the team of Professor Douglas Yu of the University of East Anglia, in Norwich, UK, can take blood that leeches suck into their stomachs, separate genetic codes of DNA, and then determine if the leech Which animals suck blood.

After 5 years and 30,000 leeches, the team hopes to apply the same technology to help prevent future diseases. For example, a sample of sewage from a market for fresh produce can be analyzed, whether or not evidence of wildlife consumption or trade - is being considered as the cause of the current corona virus.

Wildlife - germs of disease

Wildlife carrying many strains of the virus can 'jump' to other species, including humans, thanks to the virus's ability to alter genetic genes. For example, the outbreak of SARS is thought to be due to the virus 'jumping' from bats to civets to humans.

Professor Douglas Yu led the research team to separate animal DNA from blood in the stomach of leeches.(Photo: South China Morning Post).

The virus that causes acquired immunodeficiency syndrome (HIV) is suspected of being spread from chimpanzees to humans in the first half of the 20th century.

The origin of the new strain of corona virus (now known as Covid-19) is unknown, but pangolin, the world's most traded wild animal, is thought to be an intermediary host. Scientists hypothesize that the virus may have jumped from bat to pangolin before to humans.

'Dangerous wildlife. Hunting, transporting and consuming them is very dangerous, '' said Professor Yu. He also led investigations at the Kunming Zoological Institute in Yunnan, China.

His major is ecology, studying the interaction between organisms and the environment. According to the South China Morning Post, he is at the forefront of applying 'e-DNA' or 'environmental DNA' to ecological research. The 'environmental DNA' can be thought of as a collection of all the small pieces of DNA left by different species in the environment, also known as the 'DNA soup bowl'.

Thanks to the concept of 'environmental DNA' , the presence of animals can be detected by soil, water, or blood samples in the stomach of leeches.

Detecting wildlife through leeches

In the past, it was not easy to survey species in an ecosystem, like a forest.Camera traps can be used, but the camera does not capture small species. Going to the survey forest takes time and requires many people.

'Animals don't want humans to see,' Mr. Yu said.

The team chose to use leeches, because they are ubiquitous, suck lots of blood from all species, and are not 'picky eaters'. For them, the frog's blood or the bear's blood is equally delicious. They are in huge numbers - in the summer, visitors to the forests of Yunnan are appalled because every few minutes they have to get rid of leeches clinging to shoes.

Mr. Yu's group's geophysical forest survey project started in 2015, at the A Huao Shan Preserve in 170 km south of Kunming. About the size of Singapore, this is the most abundant nature in China, but has not been fully surveyed. The illegal hunting of wildlife still takes place.

The Ailao Shan Preserve is far from China's most abundant nature.(Photo: WildChina).

The team hired ranger to collect leeches during patrol trips, and rangers covered the entire forest area.

Professor Yu's group then extracted the DNA from the stomach leech, then used sophisticated statistical software to compare the different DNA codes with the DNA database of the existing database, similar to the way the software recognizes the template. The face compares an interrogator to millions of known faces, according to the South China Morning Post.

Thanks to the leeches, the team found the DNA of many species, such as the Asian black bear, the Sambar deer . The list included extinct animals.

This result is almost identical to reality.'It is true that those species were found in the right place in reality' , which is consistent with the record of animal encounters in the reserve, Mr. Yu said. 'You can trust leeches'.

The stomach of the leech contains the genetic code of the DNA of the species it has drawn.(Photo: Reuters)

Help suppress wild animal markets

Now, the fruit of Professor Douglas Yu can suddenly be an important contribution to disease prevention.

'We do not know the corona virus outbreak will occur,' he said. 'The government now says it may ban wildlife markets altogether and suppress the trade in these species.'

Enforcing the ban requires close surveillance. The technology to analyze DNA from the blood in the stomach of leeches can be applied to analyze samples of wastewater from the market, to see if there are wildlife in the market. Mr. Yu said his group was 'ready for it'.

The analysis also helped assess the effectiveness, shifting from the ban, comparing the amount of wildlife DNA code before and after suppression.

He also said that the cost of several hundred thousand yuan (6.98 yuan = 1 USD) per survey was affordable.

Hoa Nam Seafood Market, believed to be the source of the disease outbreak, was closed.(Photo: AFP).

The US-born professor also gave an assessment of the risks from wildlife trade and consumption, not only in China but also in many countries in the region.

'Only a small percentage of Chinese eat wild animals, but because they are Chinese, a small percentage is also a lot of people. Wildlife consumers are 'paying' for the supply chain from hunters, transporters, sellers - all exposed to pathogens, viruses - and that risk has erupted into a viral epidemic. corona this year, ' he told the South China Morning Post.