In the 14th century, the Black Death caused the death of tens of millions of people and depleted part of the European population. And while the disease has been largely eradicated in parts of the developed world, it still affects hundreds of people, and scientists consider it to be a re-emerging and neglected disease, especially in Madagascar, where the majority of cases worldwide occur. yearly.
When a human is infected with bubonic plague from a flea bite and does not receive proper treatment, the infection can progress and spread to the lungs, resulting in a pneumonic plague. It is the most feared clinical manifestation of plague, which is often fatal if not treated quickly. In addition, it does not necessarily have to be transmitted through fleas: infected patients can transmit the disease to others through respiratory droplets, just like COVID-19.
Now, a team of researchers has published in the journal Clinical Infectious Diseases , the analysis of a strain of Yersinia pestis , the bacterium that causes the dreaded disease, resistant to the antibiotic streptomycin, generally the first-line treatment for plague in Madagascar. This was isolated from an outbreak of pneumonic plague that took place in this country in 2013 and involved 22 people, causing three deaths.
Person-to-person transmission
“By characterizing the outbreak using epidemiology, clinical diagnostics, and DNA fingerprinting approaches, we determined, for the first time, that these Y. pestis strains can be transmitted from person to person,” explains Dave Wagner, researcher at the University of Arizona North and study leader. “ The strain in this outbreak is resistant to streptomycin due to a spontaneous point mutation, but is still susceptible to many other antibiotics, including cotrimoxazole. Fortunately, the 19 cases that were treated received cotrimoxazole in addition to streptomycin, and all survived “
“The point mutation, which is also the source of streptomycin resistance in other bacterial species, has occurred independently in Y. pestis at least three times and appears to have no negative effect on the strain, suggesting that it could persist in nature through the natural cycle of rodent-flea transmission. However, these strains are extremely rare and the mutation has not been observed in Madagascar since this outbreak ”, he concludes.
