Considered a disease of the past, the plague still worries researchers. Africa is the most affected country, but one death again took place this weekend in the United States.
The Department of Health of the State of New Mexico in the United States has announcement 1er November: an 80-year-old man died of the plague. This is the 4th human case recorded this year in this American state, the 3 other victims now healed, being a 15-year-old boy, an 11-year-old girl and a 52-year-old man.
A balance sheet that contrasts with the popular belief that the plague is a disease of the past buried in the great historical epidemics.
Yet, according to a scientific study published in The American Journal of Tropical Medicine and Hygiene, unlike smallpox which has been eradicated, the plague continues to kill across the world. While the authors of this analysis report 21,725 cases of plague and 1,612 deaths recorded between 2000 and 2009, some specialists believe that the real toll would be greater. As proof, the latest data declared by the WHO show 40,000 cases between 1991 and 2006 in 25 countries.
For about a decade, the African continent has been the biggest provider of this disease. And Madagascar holds the sad record for the most affected country. In addition, several developed countries such as the United States or Russia, regularly report new outbreaks of plague.
Listen to Professor Elisabeth Carniel, Pastor Institute : “Since the 1990s, the plague has reappeared in countries where it had disappeared for some 80 years. This means that potentially outbreaks can resume and re-explode. “
France could be affected by a plague epidemic
Even if the last French case dates from 1945 in Corsica, this risk is absolutely not excluded in France, according to scientists. “We cannot rule out this possibility, even if there is still a history of suitable rodents,” explains Elisabeth Carniel. In the United States, for example, there is everything you need in parks to allow animal reservoirs and disease to be maintained. In France, if the plague returns, no one can say if it could find an appropriate animal reservoir, until this has happened ”.
Indeed, plague is an infection caused by a bacterium (Yersinia pestis) which circulates mainly among rodents. People are usually infected when they are bitten by a flea from a rodent carrying the bacteria. Moreover, specialists point out that even if we tend to mention only human cases of plague, the absence of infected patients does not mean that the disease has been eradicated from the country.
Listen to Prof. Elisabeth Carniel : ” Currently Europe is spared, Russia which had not had a case for a very long time declared an animal outbreak this year, so some European countries could be affected at one time or another. “
To explain this increase in the number of countries affected by the plague, infectious disease specialists have several hypotheses. One of the explanations could be the decline in vigilance over the years. As long as a country knew it was infected with the plague, many surveillance measures were put in place, as was the case in India for example. “For 30 years, no case of plague has been notified in India, she believed to be rid of this disease. All the surveillance systems were completely stopped, until she resurfaced in her pulmonary form in 1994 and there was panic, ”explains Elisabeth Carniel.
Finally, another phenomenon that would explain this re-emergence of the plague could be global warming. Several studies have shown that temperature changes could promote the development of the animal reservoir and its expansion.
A very promising vaccine in need of industrial
In addition, scientists are constantly interested in this disease, its treatment, as well as the means to prevent it. Although the use of antibiotics and the implementation of better public health measures made it possible to eliminate the terrible waves of plague like that of the 14th century which decimated a third of the population, this did not however make it possible to eradicate it.
For example, the development of a preventive vaccine would represent a major step forward. “Death from plague is often caused by a problem of access to antibiotic treatment in some countries. If a vaccine that protects for several years was available, for example in Madagascar, they would be very demanding, ”concludes Elisabeth Carniel.
The problem is that the plague, like some other neglected diseases, interests researchers, but not enough industrialists. While a team from the Institut Pasteur has already obtained very promising results on a potential vaccine, due to lack of funding, it is currently impossible to test it in humans. Part of this work has also been published in 2012, on a vaccine which would protect in 100% of cases against pulmonary plague.
Listen to Prof. Elisabeth Carniel : ” We are working on a vaccine that is giving excellent results. But the number of human cases is not sufficient to interest industrialists in development. The clinical phases in humans in particular are very expensive. “
But plague research is not limited to treating the disease. Several teams around the world are trying to better understand why the bacterium responsible for the plague is able to kill with such formidable efficiency. Finally, other work in progress is analyzing certain determinisms of natural resistance. Indeed, several animals, but probably some men as well, would be able to survive this disease thanks to certain genetic predispositions. Identifying the genes responsible for this capacity for resistance to plague would make it possible in particular to develop new means of protecting oneself against “Yersinia pestis”.
.
