The people of Guinea have been locked in a life-and-death struggle with Ebola virus since last December. Nearly 60 percent of Guineans infected with the virus since then have died. To cope with the unprecedented disease, the government went so far as to ban soup made from bats.
Why bats? Because three kinds of bats from the region are believed to harbor the deadly filovirus. That's based on a survey of small animals in Gabon and the Democratic Republic of the Congo, where the Ebola virus seems to be endemic. The DRC even hosts the Ebola River that gave the virus its name. (It is a tributary of the Congo River that gives the country its name.)
Although Ebola does not kill the bats as far as scientists know, it does kill more than humans—the virus has devastated chimpanzee and gorilla populations as well. So intrepid researchers from the International Center for Medical Research of Franceville in Gabon set out to trap small animals that might harbor the disease from forest regions that had recently been devastated, starting in 2001.
All told, the researchers gathered 679 bats, 222 birds and 129 mice and other small mammals over several years to test for evidence of the Ebola virus. A few individuals from three different kinds of fruit bats tested positive for an immune response to the disease or had pieces of its RNA in their cells, although no one has yet found the actual virus in these bats. The three fruit bat species are the hammer-headed bat (Hypsignathus monstrosus), Franquet's epauletted bat (Epomops franqueti) and the little collared bat (Myonycteris torquata).
All three bats are widespread in Africa, including the regions of west Africa that are now afflicted with the disease for the first time, although it is the far western edge of their range. All eat fruit and it is unclear how or even if the disease jumped from bats to humans or if there was an intermediate host, such as apes. Researchers and health officials still do not even know whether bat-to-bat transmission, bat-to-human transmission or bat-to-other animal-to-human transmission is responsible for the beginning of the current outbreak. And it remains far from clear that bats are the hosts of the deadly zoonotic disease since two similar surveys of thousands of animals, including bats, at sites where human outbreaks occurred in the past failed to turn up any sign of Ebola virus.
What is clear is that human-to-human transmission is the main cause for the continuing outbreak this time. A genetic analysis of the virus showed that since at least May there has been no evidence of any crossover from bats or any other animal to humans. In fact, the disease bears much the same genetics from Liberia to Guinea, suggesting a single jump from some animal to a human that happened in eastern Guinea. People afflicted with the disease suffer from high fever, diarrhea, vomiting, pain and sometimes bleeding. Contact with such bodily fluids is the way the disease spreads from person to person, with symptoms of infection taking two to 21 days to manifest themselves. In fact, the genetics suggest that the outbreak in Sierra Leone stems from a single funeral held in Guinea in late April, according to a paper published in Science in August. Five of the co-authors of that paper died from Ebola in the course of researching the epidemic’s roots.
Nearly 8,400 people have now suffered from the disease, and almost half (4,033) have died, according to the World Health Organization. Those are just the reported cases, so the WHO figures likely underestimate the real impact of the disease. The epidemic has been exacerbated by distrust of government; a persistent rumor that Ebola does not exist still circulates in the region as does one that it was purposefully introduced by international medical workers.
To counteract these rumors imams in Guinea were tasked with spreading the message of good hygiene during some 7,000 sermons over the recent Tabaski Festival. And the government carried out a coordinated campaign of text messages bearing good hygiene information. In this case, hygiene primarily involves staying clear of bodily fluids from those afflicted with the Ebola virus—and that involves ending traditional burial practices that include a thorough cleansing of the corpse, which remains contagious for several days after death. Other rules are relatively simple: wash hands often; do not shake hands; and do not eat meat from animals found dead in the forest.
At the same time, however, some of the steps taken by international groups and national governments, such as quarantines, may have exacerbated the outbreak, according to medical anthropologist Barry Hewlett of Washington State University. Hewlett published the definitive account of the local response to such outbreaks in central Africa in the late 1990s and early 2000s: "Ebola, Culture and Politics: The Anthropology of an Emerging Disease." Most of those earlier outbreaks stemmed from people finding, butchering and eating apes found dead in the forest, although some seem to have started with soldiers moving across regions carrying the illness. The key to stopping an outbreak is trust, a trust developed between the sick, the infected, the local populace and authorities, so that hygiene rules can promulgate. Such trust is easily destroyed by a forcefully imposed quarantine that traps the healthy with the sick, Hewlett notes.
In the 41st week of the outbreak in Guinea the spread of the disease shows no signs of slowing, with the majority of cases to date reported in just the last three weeks. Health workers are recording roughly 100 new cases per week, including in the capital of Conakry. And it still remains unclear where the virus came from when it made the leap into humans last December in the forests of eastern Guinea. "Humans have been responding to deadly outbreaks for thousands of years," Hewlett notes. "We have minds adapted to deal with them, we have accumulated cultural knowledge of options, we have culture to adapt relatively quickly." But as it stands, WHO predicts that the outbreak will not end before next year—and that is the best-case scenario. And the host of the Ebola virus is still hiding somewhere in the forests.