The outbreak of plague that has flared up in Madagascar worries specialists in this disease that ravaged the world a long time ago. But not panic: the antibiotic treatment remains very effective and prevention measures are well known. However vigilance against this disease must be maintained.
The recent outbreak of plague in Madagascar has been worrying for specialists because it has been very unusual.
Unusual first of all because of its size: every year, more than 300 cases of plague are recorded in Madagascar during the epidemic season, which runs from September to April. But this year, 2,348 Malagasy were infected with the bacterium Yersinia pestis, and among them, 202 succumbed to the disease.
Another anomaly, unlike in previous years, three quarters of the patients were this year suffering from the pulmonary form of the plague, much more contagious, more serious and more deadly than the bubonic form.
Finally, the 2017 plague epidemic in Madagascar was almost universal and it also affected major cities, including the capital, Antananarivo, while it affected only rural areas in other years.
Will the plague of Madagascar spread? Are there other cases today in other countries?
JFL: The latest data from WHO show that this appalling disease is not just a thing of the past. Every year around the world, around 600 people are affected. According to the latest figures from the World Health Organization, from 2010 to 2015, there were 3248 cases of plague in the world, including 584 deaths.
After drastic measures were put in place (with the support of WHO), the Malagasy government officially proclaimed November 27th as "the end of this epidemic of urban lung plague", but surveillance must continue.
It's not like smallpox that has been completely erased from the map?
JFL: Yes, smallpox has been eradicated by vaccination, but cholera and poliomyelitis are still there, and as with these diseases, plague cases appear mostly in unhealthy places and associated with great misery. Today, it is in Africa, for example in the Democratic Republic of Congo and also in Madagascar that the disease strikes the most.
But many developed countries, such as the United States or Russia, regularly report new outbreaks of plague. This is related to the existence of a wild animal (a different species of rodent depending on the country) that serves as a reservoir for the disease
Does this mean that the plague is at the gates of Europe?
JFL: Currently Europe is spared, but we are not completely safe because the plague reappears in countries where it had completely disappeared, sometimes for 80 years. For example she returned to Algeria where there had been none since the famous plague described by Camus in Oran (which succeeded that of Algiers) (1944-45). Same in Jordan. With the proliferation of foci of war and mass transfers of populations, the plague could reappear on a large scale, including in France.
Do we risk something in France?
JFL: The last big epidemic in France dates from 3 centuries ago! Between 1720 and 1723, an epidemic of plague in Marseilles and its region had killed nearly 120,000 of the 400,000 inhabitants of the region at that time!
But the last French case is not buried in history in France since it is located in Corsica in 1945. So the risk of a resurgence of the plague is absolutely not excluded.
In addition, when we see the proliferation of rats in Paris, we say that it would not much to go back.
How to explain this reemergence of the pulmonary form in Madagascar?
JFL: One of the explanations could be the decrease of the vigilance of the health authorities over the years. As long as a country is infected with plague, many surveillance measures are put in place and antibiotic treatments put in place? With these precautions, the epidemic does not take. But as cases become rare, some countries drop their guard.
We are also talking about global warming. Several studies have shown that changes in temperature could favor the development of the animal reservoir and its expansion, or even a change in virulence of bacteria that become more aggressive.
This animal tank, as you say, are the rats? The plague still remains associated with misery?
JFL: And a bacterium! Yersinia Pestis, named after its discoverer Alexander Yersin. This bacterium often lives in the blood of mammals, including rats and related animals that are the reservoir where the bacterium persists. But you need a vector to transfer the bacteria to humans. This vector is a flea that has sucked the tainted blood of the rodent and can transfer the bacillus to humans if it comes too close to rats.
In causes of reappearance of the plague, come the major sanitary degradations (the wars), the great human migrations and the international trade. They could help the bacteria to end up in the West.
What are the symptoms of the plague?
JFL: The first symptoms of the plague appear more or less quickly, from a few hours to five days after the contamination.
Bubonic plague is the most common form of the disease (80% to 93%). It is manifested by a high fever, a poor general condition and an increase in the volume of the lymph node that drains the area of bite of the flea. This hypertrophied and painful ganglion is called "bubo". He can begin to fester and then heal.
In cases of pulmonary form of the plague, the disease begins as particularly severe pneumonia (fever, cough, chest pain), which evolves very rapidly to sepsis, which is a generalized infection, fatal in a few days ... and most importantly very contagious. This is what happened in Madagascar.
Does one have treatment?
JFL: Yes, thankfully, the bacillus of the plague is still susceptible to antibiotics, which allowed with hygiene measures to no longer have these terrible epidemic waves. But must we have access to these drugs, which is not always the case in some regions. Hence the persistence of homes.
The ideal solution is the vaccine?
JFL: Several vaccines against plague have already been developed over the years, but they have serious side effects. In addition, they have no efficacy on pulmonary plague.
A team from the Institut Pasteur has already obtained very promising results on a potential vaccine, but for lack of funding, it is currently impossible to test it in humans. The industrialists are not interested in this plague market which remains undeveloped, we must admit.
In conclusion, do not panic, the plague has not disappeared, so far, an epidemic of plague is not for tomorrow.