In the beginning of September his family brought him back to the hospital, but by then he was already in very poor condition. He vomited uncontrollably, had an acute case of diarrhea, headaches and troubles with breathing. In the days that followed he started bleeding from his nose, eyes and gums. Unfortunately, there were no doctors in the mission hospital, only nurses, so they did everything in their power to help him, but were unable to determine the real cause of the disease. On September the 8th, approximately two weeks after the first symptoms of the illness had occurred, Mabalo died.
“We’re all going to bleed to death!”
In keeping with tradition, Mabalo’s wife Mbunzu, who took care of him all along, washed her husband’s body with her mother, her husband’s mother, her sister and other close female relatives to prepare him for his funeral. Soon after the funeral, Mabalo’s relatives and friends who were present at the ceremony all developed the same symptoms as those the deceased teacher had shown only a couple of days earlier. Some nurses from the hospital where Mabalo was being treated fell ill as well. People started to panic; it seemed that they were all going to bleed to death.
On September 15th, after the director of the mission hospital requested his council, Dr. Ngoy Mushola, a doctor from the nearby town Bumba, came to Yambuku. He quickly discovered that they were dealing with a case of a highly contagious disease that spread at a rapid pace throughout the town and the neighboring villages. He wrote down a detailed description of the symptoms and tried to get the people to establish at least a minimal quarantine for the diseased. This was necessary because the locals were used to burying their dead right next to their houses or even inside their dwellings, which only accelerated the rate at which the disease was spreading. On 17 September Dr. Mushola sent his first official report of the outbreak of this contagious disease to those responsible in Kinshasa and requested immediate assistance.
On 23 September two experts on microbiology and epidemiology, otherwise professors at the National University of Zaire, came to Yambuku for a closer examination of the situation. After they arrived, they diagnosed the illness as an outbreak of atypical yellow fever and soon left the area of epidemic. They brought a very ill Sister and two other members from the mission with them to Kinshasa. The samples of the diseased Sister’s blood were then sent to the Pasteur Institute in Paris through the French Embassy with a request to try and find out which disease it was. At the Institute it was discovered that the disease was caused by a new virus which was named Ebola after a stream in the vicinity of Yambuku from where it was supposed to originate.
Shortly afterwards, in the beginning of October, the local authorities isolated the area and surroundings of the town of Yambuku with road blocks which were under the surveillance of the Army. In the larger nearby town of Bumbu movement was also very restricted, two field hospitals were set up as quarantines, and traveling to other parts of the country was prohibited. Despite the efforts, the disease spread to many of the nearby villages, infecting 318 people of which 280 (almost 90%) died from the consequences of the disease.
At the same time, a slightly different version of the virus spread from this area in the heart of Africa to the south of Sudan. Here, the epidemic affected 284 people of which 151 died, meaning that the Sudanese form of the virus was less deadly, with a mortality of “only” a little more than 50 percent.
The monkey connection
While studying the virus that was killing people in the north of Congo and in the south of Sudan, virologists in laboratories specially equipped for researching the most contagious diseases discovered that they were dealing with a similar virus that had appeared in Europe a mere decade earlier. In 1967 in Marburg, Germany, the local clinic for infectious diseases admitted a number of severely ill patients who had a very high fever, suffered great pain and bled from several parts of the body. It turned out that all of them worked at the same pharmaceutical company and were infected by a virus they had contracted from monkeys imported from Uganda. Half of the monkeys that were needed to prepare cell cultures, which were used to produce vaccines, had already died on the way from Africa.
Apart from Marburg, some cases of infection with the same virus were also discovered in Frankfurt and Beograd. 25 people were infected by direct contact with the monkeys and seven did not survive the disease. Besides these primary infections, six more individuals fell ill, but there were no death casualties.
When it comes to outbreaks of this deadly viral disease, the fortunate thing is that the Ebola virus kills too rapidly to effectively spread among people. The infected individual quickly becomes too afflicted and weak to walk around and spread the infection, so Ebola viruses are limited. From 1976 less than 2000 people contracted Ebola, but the mortality of each outbreak was as high as 50-90%. One of the highest death rates was recorded during the 1976 outbreak in Congo.
Could bats be the carriers?
Although we are much more familiar with the ways these deadly diseases function and spread today than we were decades ago, in African countries outbreaks of Ebola and similar viruses still occur. In 2007, around a hundred people were afflicted by Ebola with a mortality of 25 percent. In the middle of July this year, a Dutch woman who had returned from her travels in this African country also died from the consequences of an Ebola-like virus. Supposedly she got infected during a visit to a cave where she came into close contact with a bat.
On the HealthMap website a map of the world enables us to daily follow the visual representation of different sources of news reporting about disease outbreaks. The website automatically tracks professional health information sources and warnings as well as newspapers and other news sources, classifies them according to the level of danger and locates them on the map. At the beginning of this summer, a red flag marked the Dutch city of Leiden where local doctors wearing protective gear in a specially secured part of the hospital were treating the diseased tourist.
However, Ebola does not only attack people, but can also affect monkeys and forrest antelopes. This very disease has been the cause of death of many gorillas and, according to estimations, could significantly weaken their population in the decades to follow, so vaccines against Ebola are also being developed for gorillas.
One of the more important questions concerning Ebola and similar viruses is who is their natural host, or how they are transmitted to people, monkeys and some other animals. For some time now it has been suspected that the natural reservoir of this disease are bats, but nobody has yet succeeded in providing incontestable evidence to confirm this theory. However, it has been established that bats are not affected by the disease even if infected with the virus. One of the first cases of infection in Sudan in 1976 occurred in an employee of a cotton factory which was also the home of a number of bats. It has also been suggested that animals might get infected by eating fruits that had been chewed on and cast off by bats and are later collected and eaten by, for example, monkeys. The teacher Mabalo Lokela, who was officially the first to have died from the consequences of an Ebola infection, supposedly ate the meat of antelope, also a disease carrier, during his travels in the north of Congo.
For exceptionally dangerous diseases, such as the Ebola or anthrax infections, the American Food and Drug Administration (FDA) even changed its rule to only approve a vaccine after it had been successfully tested on people. For these most deadly diseases it is enough if scientists are able to prove immunity in at least two species of animals. Naturally, it would be difficult to find someone who would be “brave enough” to take an injection of a new vaccine and then intentionally get infected just to prove that the vaccine really works.
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