The plague epidemic which has flared in Madagascar worries specialists in this disease which ravaged the world a very long time ago. But don’t panic: the antibiotic treatment remains very effective and the preventive measures are well known. However, vigilance against this disease must be maintained.
The recent plague epidemic which flared in Madagascar was worrying for specialists because it was very unusual.
Unusual first of all because of its magnitude: each 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 have been infected with the bacteria Yersinia pestis, and among them, 202 have succumbed to the disease.
Another atypia, unlike in previous years, three quarters of the patients this year were affected by the pulmonary form of plague, clearly more contagious, more serious and more fatal than the bubonic form.
Finally, the 2017 plague epidemic in Madagascar was almost general and it also affected large cities, in particular the capital, Antananarivo, while it only affected rural areas in other years.
Will the plague of Madagascar spread? Are there other cases today in other countries?
JFL: The latest data from the WHO shows 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 3,248 cases of plague in the world, of which 584 were fatal.
After the implementation of drastic measures (with the support of the WHO), the Malagasy government officially proclaimed on November 27 “the end of this epidemic of urban pulmonary plague”, but surveillance must absolutely continue.
Isn’t it like smallpox that has been completely wiped off the map?
JFL: Indeed smallpox has been eradicated thanks to vaccination, but cholera and polio are still there and as with these diseases, cases of plague appear especially in unsanitary places and associated with great poverty. Today, it is in Africa, for example in the Democratic Republic of the Congo and also in Madagascar that the disease strikes the most.
But several developed countries, such as the United States or Russia, regularly report new outbreaks of plague. This is linked to the existence of a wild animal (a different species of rodent depending on the country) which 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 immune to it because the plague is reappearing 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 hotbeds of war and massive population transfers, the plague could reappear on a large scale, including in France.
Are we risking something in France?
JFL: The last major epidemic in France dates back 3 centuries! Between 1720 and 1723, a plague epidemic in Marseille and its region had killed nearly 120,000 out of the 400,000 inhabitants that the region had at that time!
But the last French case is not buried in history in France since it was 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 to ourselves that it would not take much for it to start again.
How to explain this re-emergence of the pulmonary form in Madagascar?
JFL: One of the explanations could be the decline in the vigilance of health authorities over the years. As long as a country knows it is infected with the plague, many surveillance measures are put in place and antibiotic treatments put in place? With these precautions, the epidemic does not take hold. But as cases are becoming rare, some countries are letting their guard down.
We also talk about global warming. Several studies have shown that temperature changes could promote the development of the animal reservoir and its expansion, or even a change in the virulence of bacteria which become more aggressive.
This animal tank, as you say, are the rats? The plague is still associated with misery?
JFL: And to a bacterium! Yersinia Pestis, named after its discoverer Alexandre Yersin. This bacteria often lives in the blood of mammals, especially rats and related animals which are the reservoir where the bacteria persist. But a vector is needed to transfer the bacteria to humans. This vector is a chip which has sucked the contaminated blood of the rodent and can transfer the bacillus to humans if the latter gets too close to the rats.
In the causes of reappearance of the plague, come the major sanitary degradations (wars), the great human migrations and the international trade. They could help the bacteria find their way to the West.
What are the symptoms of plague?
JFL: The first symptoms of plague appear more or less quickly, a few hours to five days after infection.
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 size of the lymph node which drains the area of the bite of the flea. This enlarged, painful lymph node is called a “bubo”. It may start to fester and then heal.
In cases of the pulmonary form of the plague, the disease begins as a particularly severe pneumonia (fever, cough, pain in the chest), which progresses very quickly to sepsis, which is a generalized infection, fatal in a few days … and above all very contagious. This is what happened in Madagascar.
Do we have a treatment?
JFL: Yes, fortunately, the plague bacillus is still sensitive to antibiotics, which made it possible, with hygiene measures, to no longer have these terrible epidemic waves. But is it necessary to have access to these drugs, which is not always the case in some regions. Hence the persistence of outbreaks.
The ideal solution lies in the vaccine?
JFL: Several plague vaccines have already been developed over the years, but they have serious side effects. In addition, they have no effect on pulmonary plague.
A team from the Institut Pasteur has already obtained very promising results on a potential vaccine, but due to lack of funding, it is currently impossible to test it in humans. Manufacturers are not interested in this plague market which remains underdeveloped, it must be admitted.
In conclusion, do not panic, the plague has not disappeared, however, a plague epidemic is not for tomorrow.
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