Bushmeat causes Ebola

Ebola - deadly virus from bush meat

Vienna / Guinea - Death lurks in the African tropical forest. Hunters kill monkeys, small antelopes and porcupines there, eat their prey with the family or sell it as "bush meat" at the market. Game is a popular source of protein for people, but preparation and consumption can sometimes have fatal consequences. The animals can be infected with highly dangerous germs such as the Ebola virus.

Dangerous strains of viruses

Five different strains or species of the Ebola virus are known to science today. The first to be discovered in 1976 was the Zaire tribe, which at the time claimed at least 280 lives in the Congo. Most Ebola outbreaks are caused by this type of virus. The pathogens currently rampant in Guinea also belong to the Zaire tribe, explains tropical medicine specialist Esther Sterk from the organization "Doctors Without Borders" in Geneva to STANDARD. Other often fatal variants are the Sudan and Bundibugyo Ebola viruses. The West African Ta Forest strain and the East Asian Reston Ebola virus, on the other hand, do not appear to pose a serious threat to humans.

The pathogens are transmitted through the body fluids of infected animals and humans - blood, saliva, sperm and the like. The germs penetrate the body through the mucous membranes or injuries. A small cut, for example, becomes a risk when cutting game.

Ebola is a tricky virus, says Esther Sterk. It masks itself against the immune system and can therefore initially spread unhindered. "Before you notice it, it is already in all organs," emphasizes the expert. The incubation period is two to 21 days. "Most patients show the first signs of illness after about eight to 14 days." The more viruses that get into the body when infected, the faster it happens.

Unspecific symptoms

Unfortunately, the initial symptoms aren't very specific. Those affected first get a fever, accompanied by weakness, headache and muscle pain. Such complaints occur with various tropical diseases. Vomiting and diarrhea set in later. In the final stages, most patients experience internal and external bleeding. The pathogens have already destroyed so much tissue that the blood vessels are leaking. At the same time, coagulopathy often occurs, as Esther Sterk explains. The blood's ability to clot decreases.

The clear diagnosis of Ebola disease is made using laboratory tests. Doctors and nursing staff should therefore always be on their guard when working in remote African regions - for their own safety. Regular disinfection and the use of protective clothing, rubber gloves and breathing masks are mandatory when dealing with suspected Ebola cases. "If you follow the general precautionary measures, the risk of infection is low," says Sterk. In contrast to flu viruses, Ebola pathogens cannot be transmitted via the air either. However, a droplet infection at a short distance is possible.

Contagious beyond death

The mortality rate from Ebola can be up to 90 percent. Most people die less than two weeks after the first symptoms appear. But some patients survive the disease. Why they defeat the Ebola virus is not yet fully understood. The original virus dose certainly plays a role, says Sterk, as does the general health of an infected person. The tropical medicine specialist emphasizes that there is still a risk for the relatives of Ebola patients after their death. "The corpse is full of viruses." Therefore, mourning rituals such as washing the dead, which are widespread in many places, must be avoided. A quick cremation or burial in a tightly sealable body bag is safest.

In the food chain

Researchers have long puzzled over the exact origin of the Ebola virus. Monkeys, including chimpanzees and gorillas, are more often involved in the transmission of the pathogen, but they themselves also die from the disease. The original hosts, the so-called virus reservoir, appear to be large, fruit-eating bats. Also known as flying foxes, they are found in large parts of Africa. The animals carry the virus in themselves, but do not become ill (see, inter alia: BMC Infectious Diseases, Vol. 9, p. 159).

They form antibodies in a targeted manner and thereby keep the germs in check. Humans and other mammals are therefore only false hosts. The Ebola viruses can multiply in their bodies almost unhindered. Nevertheless, the pathogens do not manage to spread widely in their populations. They kill too quickly for that. (Kurt de Swaaf, DER STANDARD, 8.4.2014)