For several weeks, the Democratic Republic of the Congo has been facing a new outbreak of the hemorrhagic fever Ebola. Where does this virus come from? What is the latest on the current crisis? An update with Arnaud Fontanet, Professor at the CNAM and Head of the Epidemiology of Emerging Diseases Unit at the Institut Pasteur in Paris.
Arnaud Fontanet, Professor at the CNAM and Head of the Epidemiology of Emerging Diseases Unit at the Institut Pasteur.
Compared with the Ebola outbreak in 2014, the response in the DRC was much quicker.
In 2014, the WHO called Ebola "the worst health crisis of modern times". What is the history of this disease which claimed more than 11,000 lives four years ago?
The first known outbreak of Ebola dates back to 1976 in the former Zaire, now the Democratic Republic of the Congo. This first appearance was characterized by an outbreak of hemorrhagic fever in a clinic deep in the tropical forest, close to the river Ebola, hence the name of the disease. It was particularly worrying at the time because an estimated 90% of cases were fatal. Healthcare workers who came into contact with patients also became infected and were among the victims. It was a very contagious, unknown hemorrhagic fever with a very high mortality rate.
At the time, teams from the Centers for Disease Control and Prevention (CDC), the Institute of Tropical Medicine Antwerp and the Institut Pasteur were involved in investigating this first outbreak. The virus was isolated at the Institute of Tropical Medicine Antwerp, in Belgium, from a sample sent by Peter Piot [Editor's note: current director of the London School Of Hygiene and Tropical Medicine, and, back then, a young doctor at the Antwerp Institute]. As the outbreak occurred in a very remote area, it eventually died out on its own. Ebola claimed 280 lives. Since then, there have been a few dozen limited outbreaks of Ebola in this region of central Africa.
The large outbreak in West Africa in 2014 marked a major shift. It was the first time an outbreak had been seen in that area of Africa and even today, it is not known how the virus got there. It was no doubt carried by bats but this has not been proven. As the disease was unknown in the West at the time, diagnosis came late. Four months passed between the first cases and the identification of the virus by the National Reference Center for Viral Hemorrhagic Fevers at the Institut Pasteur in Lyon, headed by Sylvain Baize. The virus broke out in a border area between Guinea, Sierra Leone and Liberia. It was able to circulate, more easily than when it was confined to remote areas, and affect the capitals of the three countries concerned – Conakry, Freetown and Monrovia. But when the virus reaches urban areas, the risk of it spreading is obviously much greater. It took over a year to contain this major outbreak. The response from the World Health Organization (WHO) was slow and inappropriate. The scale of the outbreak was under-estimated at the start. Lessons were no doubt learned from this failure because the response to the new outbreak, which has just begun in the Democratic Republic of the Congo, was much better.
How did this disease spread to humans?
Bats are reservoirs for the virus and it can infect a great number of animals. Outbreaks are most often found in large primates, such as gorillas and chimpanzees, in the weeks leading up to an outbreak in humans. It is the hunters who, by coming into contact with affected and more easily captured animals, become infected with the disease themselves and take it back to their villages. As these outbreaks often occur in remote villages in the tropical forest, they resolve themselves because the virus cannot get out of these isolated communities which are under strict quarantine.
What are the symptoms of Ebola infection?
Incubation of the disease is highly variable, ranging from 2 to 21 days but 8 to 12 days on average. It starts with a fever, a sign that could suggest influenza. As the disease progresses, patients can present hemorrhagic symptoms with severe bleeding that very often results in death.
Vomiting and diarrhea were observed in the outbreak in West Africa. These are not typical symptoms of Ebola virus infection but they led to severe dehydration, which claimed many lives.
The virus is spread by contact with bodily fluids, and patients are contagious during the advanced stages of the disease, when they present with bleeding. Burial rituals are often cited as a source of contamination because the family comes into contact with the body (if only just to wash it) and, according to tradition, it is important to touch the body of the deceased. But the virus is still present after the patient dies. So, in this context, it is very important to meet communities to discuss ways in which they can perform these rituals while avoiding contact. It is not a question of banning these rituals, which are culturally important, but of performing them differently so as not to expose families of the deceased to the virus. During the last outbreak of Ebola, this experience showed us the role that anthropologists could play in understanding these rituals and developing new practices that would meet cultural demands while preventing contamination.
What are the signs that the new outbreak currently affecting the Democratic Republic of the Congo has been handled better?
The current outbreak began in a province in the northwest of the Democratic Republic of the Congo, in Bikoro, then in Iboko, a border area with the Republic of the Congo (Brazzaville). Although the first cases probably date from April 2018, the Ebola outbreak was confirmed as early as the beginning of May.
Ebola is known in the DRC. Symptoms were immediately suggestive of Ebola. Diagnosis was therefore established in a laboratory in Kinshasa. Once the results had been confirmed, there was a strong response from the national authorities. The World Health Organization also acted rapidly. Its Director-General even visited the area in the first half of May. International stakeholders, like the well-prepared Médecins Sans Frontières, sent their support, particularly for patient care.
Today, around fifty cases have been reported with 35 deaths. The appearance of cases in Mbandaka, a city with 1.2 million inhabitants located over 100 kilometers north of the start of the outbreak, is a cause for concern.
But, compared with the 2013-2014 outbreak, the response was much quicker and, we hope, more effective. Isolation measures have been introduced. In the field, a dedicated area has been set up at Wangata General Hospital in Mbandaka to treat patients. Above all, a vaccine is now available that was clinically tested during the outbreak in West Africa. It is the first time that we have had a vaccine to tackle Ebola. Those in close contact with patients and front line healthcare workers treating people with the disease [some 400 people] have therefore been vaccinated. The vaccine is complicated to use however as it needs to be kept at -80°C. Will these measures be enough to contain the spread of the virus? It is not yet known.
Courtesy of the National Conservatory of Arts and Trades (CNAM).