Release date: 2017-06-15 Source: Science Network / Zong Hua Jiangsu Asbao Medical Technology Co., Ltd. , https://www.iigloves.com
Image source: K. KUPFERSCHMIDT/SCIENCE
At the beginning of the new moon, the jungle is as dark as the deep sea. 4 people sat in a plastic chair and waited. Despite the hot weather, they wore long-sleeved shirts, gloves and masks. In the darkness, on top of their heads, an invisible huge net hangs between the two trees. They are fishermen in the sky, waiting for the prey to arrive.
These people are listening to the short and hoarse voice of the hammerhead bat. Every night, dozens of male hammerhead bats gather in this tropical rainforest region in the northern part of the Republic of the Congo and use their voices to compete for female bats. Hammerhead bat wings are stretched to 1 meter and are the largest bats in Africa. They may be the answer to one of the mysteries of virology, where is the deadly Ebola virus lurking?
This problem has plagued researchers for more than 40 years. In 1976, the Ebola virus suddenly appeared in the jungle near the Ebola River, a few hundred kilometers northwest of the area. This unknown pathogen was raging in a small church hospital in Yangbuku (now in the Democratic Republic of the Congo) and surrounding villages. The victim first developed symptoms such as sore throat, fever, headache and stomach aches. Subsequently, their eyes, nose and other channels began to bleed. These people died within a few days. The Ebola virus infects 318 people and causes 90% of deaths before disappearing.
Since then, the virus, now named after its emerging river, has reappeared in an unpredictable way. Most occur in central Africa, but sometimes further, causing small but fatal outbreaks in one or two villages. Subsequently, at the end of 2013, Ebola appeared in Guinea and spread to the densely populated capital Conakry. The epidemic quickly engulfed nearby Liberia and Sierra Leone. Of the largest outbreaks on record, more than 11,000 people died in the three West African countries.
Grab the bat in the jungle
Vincent Munster, a 44-year-old virologist, usually works on another distant continent. He studied Ebola and other dangerous pathogens in a high-security laboratory run by the National Institute of Allergy and Infectious Diseases in Montana, USA. Early in his career, Munster participated in a controversial “function-acquisition†trial at the Erasmus Medical Center in Rotterdam, the Netherlands, to transform the deadly H5N1 avian influenza virus, making it easier for mammals (probably also included People) spread.
However, these days, he mentions less about viral genes and proteins, and more talk about viral ecology: an interactive network that allows animal-borne viruses to spread between species. Deforestation, hunting, and other human violations of the original environment have played a role in linking people to microbes that are lurking there. Munster said that once new pathogens jump to humans, the forces of globalization, urbanization and mobility will allow them to spread faster.
This is why Munster came to this jungle to catch bats. More than half of all outbreaks caused by the Ebola Zaire virus, one of the deadliest Ebola viruses, occur here or in the neighbouring Democratic Republic of the Congo. “This is the world's largest Ebola hotspot,†Munster said. In fact, on 11 May, the Ministry of Health of the Democratic Republic of the Congo informed the World Health Organization that a new round of Ebola outbreaks had erupted in the country. To date, 37 suspected cases have occurred in seven villages, and several have lost their lives. Munster is planning to travel to the area again to help investigate the outbreak.
Sampling animals
At two in the morning, Munster and epidemiologist Sarah Olson started a day's work. Her work began at the end of the Congolese veterinarian Alain Ondzie, who worked for the Wildlife Conservation Society (WCS). Olson sterilized his arm, put on protective clothing, put on a mask, a respirator, and put on a pair of leather gloves on two layers of plastic gloves. She untied a bag and took it to a tent that served as a temporary lab. In addition to leather gloves, other similar Munsters are waiting. A bare light bulb shines on the tent, making it a bright island in the dark forest. The black walls are made of banana leaves.
Olson grabbed the bat's head tightly between the thumb and forefinger and exposed its lower limbs. Munster massages the bat's bladder until the urine flows into a plastic bottle. Subsequently, Olson released the entire animal. Munster checked and measured the bat, and another researcher took notes next to it.
Olson works for WCS. There, she studied how Ebola affects chimpanzees and gorillas. Everyone's guess is different about how the virus spreads from bats to primates. However, it is as dangerous to these primates as it is to humans. This is why WCS has become a partner for Munster to explore the truth. “In addition to illegal hunting, Ebola is the biggest threat to gorillas,†said WCS primatologist Emma Stokes. Some estimates show that between 2005 and 2012, Ebola caused about half of the gorillas in the Republic of Congo to die. This is a huge blow to the species, as about 60% of the world's gorillas live in the northern part of the Republic of the Congo. This is where the Munster team works.
In turn, gorillas and other primates pose a threat to humans who often come into contact with viruses through the treatment of dead animals or the consumption of jungle meat. The reason why Ondzie's other job is to visit the local community to urge people not to touch the dead animals in the forest but to inform the WCS is for this reason.
Test sample
The first bat analyzed that night was alive and looked healthy. “Very good physical condition,†Munster said. “The head is 42 mm long, 97 mm in length and 95 mm in the lower limbs.†He wiped the bat's mouth, nostrils and anus with a cotton swab. Suddenly, the animal stepped back and a claw scraped Munster's plastic gloves. Although he did not see the tears flowing out, he lost the outer gloves and replaced them with a new one.
Then came the most dangerous part: when Olson grabbed the bat, Munster inserted a needle into the blood vessels of the wings and slowly pulled the blood out. "You have to be very careful," he said. "After all, we are talking about Ebola."
Munster knows how to deal with deadly viruses. During the Ebola outbreak in 2013-2015, he tested hundreds of samples in Monrovia. Too many samples are positive for the virus. “We underestimated the virus,†Munster said. He decided not to make this mistake anymore. The Republic of the Congo is undergoing rapid changes. The researchers’ tents may be only 100 meters away from a road that divides the country into two. The road extends 800 kilometers to the south and goes directly to the capital, Brazzaville. When Munster first came here several years ago, it was still a red land. Today, this road has become a smooth asphalt road. If the Ebola virus emerges again from the forest, it is possible to reach Brazzaville tomorrow and arrive in Boston, Mumbai or Berlin in a day.
The team checked 13 bats one by one and released them. At around 5 in the morning, the scream of the hammerhead bat gradually faded. The last bag was opened and the researchers wiped the last animal. They stored samples collected at night in liquid nitrogen. Since the shipment of these materials, which may contain Ebola, involves multiple departments, the sample may not be able to reach the United States within a few months.
Once the samples arrive, they will be separated, some of which will be used to test Ebola RNA in Munster's lab. If the test proves positive, the researchers will mix another sample with the cultured bat and monkey cells to test whether it is positive for the activated virus. “You just need to add a small sample to your cells and wait to see if there is a virus replication.†Munster said that if enough samples test positive, his team could establish a virus level. The pattern of fluctuations within the bat population. This type of monitoring can help scientists understand the factors that trigger the flu virus to jump from animals to humans. And this may one day bring a similar understanding of the Ebola virus.
In a tropical rainforest camp, a group of researchers trapped the hammerhead bats and sampled them overnight.