Researchers search for the Ebola virus through bats in the Congolese jungle.

At the beginning of the new month, the jungle was as dark as the deep sea.
four people sitting in plastic chairs, waiting.
the hot weather, they wore long-sleeved shirts, gloves and masks.
darkness, above their heads, an invisible giant net hung between the two trees.
are fishermen in the sky, waiting for their prey to arrive.
these people were listening to the short, hoarse cry of hammerhead fruit bats.
night, dozens of male hammerhead bats gather in this tropical rainforest area in the northern part of the Republic of Congo and compete for female bats with their calls.
hammerhead fruit bat has a wingspan of up to 1 meter and is the largest bat in Africa.
they may be the answer to one of the mysteries of virology: where exactly is the deadly Ebola virus lurking? The problem has plagued researchers for more than 40 years.
1976, the Ebola virus suddenly emerged from a jungle hundreds of kilometers northwest of the region, near the Ebola River.
the then unknown pathogen is raging in a small church hospital in Janbuku, now in the Democratic Republic of the Congo, and surrounding villages.
victim initially developed symptoms such as sore throat, fever, headache and stomach pain.
, their eyes, nose and other cavities began to bleed.
these people died within a few days.
ebola virus infected 318 people and killed 90 percent before it disappeared.
, the virus, now named after the river in which it appears, has re-emerged in unpredictable ways.
are found in central Africa, but sometimes further afield, causing small but deadly outbreaks of disease in one or two villages.
, Ebola appeared in Guinea at the end of 2013 and spread to the densely populated capital Conakry.
outbreak quickly engulfed nearby Liberia and Sierra Leone.
more than 11,000 people have died in the three West African countries in the largest outbreak on record.
, a 44-year-old virologist who has been caught catching bats in the jungle, usually works on another remote continent.
in a high-security laboratory run by the National Institute of Allergy and Infectious Diseases in Montana, USA, where he studies Ebola and other dangerous pathogens.
Early in his career, Munster participated in a controversial "functional gain" trial at Erasmus Medical Center in Rotterdam, the Netherlands, to transform the deadly H5N1 avian influenza virus to make it more likely to spread among mammals, presumably humans.
, however, he talks less about viral genes and proteins and more about viral ecology: the network of interactions that allow animal-borne viruses to spread between species.
felling of trees, hunting and other human violations of the pristine environment have all played a role in linking humans to the microbes lurking there.
Munster says the forces of globalization, urbanization and mobility can spread faster once new pathogens jump on humans.
that's why Munster came to the jungle to catch bats.
more than half of all outbreaks triggered by the Ebola Zairian virus, one of the deadliest, have occurred here or in the neighbouring Democratic Republic of the Congo.
the world's largest Ebola hotspot.
," Munster said.
, on 11 May, the Ministry of Health of the Democratic Republic of the Congo informed the World Health Organization of a new Ebola outbreak in the country.
, 37 suspected cases have been reported in seven villages, resulting in the death of several people.
Munster is planning to travel to the area again to help investigate the outbreak.
2 a.m., Munster and epidemiologist Sarah Olson began a day's work.
her work began at the end of Alain Ondzie, a Congolese veterinarian who works for the Wildlife Conservation Society (WCS).
olson had his arms disinfected, put on protective clothing, put on a mask, a respirator, and another layer of leather gloves on two layers of plastic gloves.
untie a bag and take it to a tent that serves as a makeshift laboratory.
munster, who was wearing similar clothes except leather gloves, was waiting.
a bare light bulb shines on the tent, making it a bright island in a dark forest.
black walls are made up of banana leaves.
Olson grabbed the bat's head between his thumb and forehead and exposed his lower limbs.
Munster massages the bat's bladder until urine flows into a plastic bottle.
, Olson let go of the whole animal.
Munster examined and measured the bat, while another researcher took notes next to him.
Olson works for WCS.
, she studied how Ebola affected chimpanzees and gorillas.
's guess about how the virus spreads from bats to primates is different.
, however, it is as dangerous to these primates as it is to humans.
is why WCS has become Munster's partner in the exploration of the truth.
" in addition to illegal hunting, Ebola is the biggest threat to gorillas.
," says Emma Stokes, a WCS primatologist.
estimates, Ebola killed about half of the gorillas in the Republic of Congo between 2005 and 2012.
a huge blow to the species, as about 60 per cent of the world's gorillas live in the northern part of the Republic of Congo.
is where the Munster team works.
in turn, gorillas and other primates pose a threat to humans who often come into contact with the virus by treating dead animals or eating jungle meat.
another job for Ondzie was to visit local communities to urge people not to come into contact with dead animals in the forest and to inform WCS, which is why.
first bat analyzed that night from the test sample was alive and looked healthy.
"very good physical condition.
," Munster said, "the head is 42 mm long, the body is 97 mm long, the lower limb is 95 mm."
" he wiped the bat's mouth, nostrils and anus with a cotton swab.
, the animal backed away, and one paw scraped Munster's plastic gloves.
didn't see blood coming out, he lost his outer gloves and changed into a new pair.
was then the most dangerous part: when Olson grabbed the bat, Munster inserted a needle into the blood vessels of his wings and slowly pumped blood out.
"You have to be very careful.
," he said, "after all, we're talking about Ebola."
Munster knows how to deal with deadly viruses.
tested hundreds of samples in Monrovia during the 2013-2015 Ebola outbreak.
too many samples tested positive for the virus.
"We underestimate the virus.
," Munster said.
decided not to make such a mistake again.
rapid changes are taking place in the Republic of the Congo.
the researchers' tents may be only 100 metres from a road that divides the country in two.
the road extends 800 kilometres south to the capital Brazzaville.
when Munster first came here a few years ago, it was still a red land.
today, the road has become a smooth asphalud road.
Ebola virus emerges from the forest again, it could reach Brazzaville tomorrow and Boston, Mumbai or Berlin in another day.
team examined 13 bats one by one and released them.
about 5 a.m., the sound of hammerhead fruit bats faded.
the last bag was opened and the researchers wiped the last animal.
they stored samples collected at night in liquid nitrogen.
because the shipment of materials that may contain the Ebola virus involves multiple departments, samples may not reach the United States for months.
samples arrive, they will be separated, some of which will be used to test Ebola RNA in Munster's lab.
if it turns out to be positive, the researchers will mix another sample with cultured bat and monkey cells to test whether they are positive for the live virus.
"You only need to add a small sample to your cell and wait to see if there is a virus replication."
, Munster said, if enough samples test positive, his team could establish a pattern of how virus levels fluctuate within bat populations.
monitoring could help scientists understand what causes influenza viruses to jump from animals to humans.
and this may one day lead to a similar understanding of the Ebola virus.
.