An infectious disease that has almost vanished appears to be returning. In a new article this week, scientists warn that cases of diphtheria have gradually increased in recent years, although there are signs that antibiotics and vaccines against the disease bacteria may be in danger of losing its potency as the germ continued to evolve.
Diphtheria is caused by certain strains of the bacteria Corynebacterium diphtheriae. It is mainly spread by means of respiratory droplets and, more rarely, through skin contact with infected wounds. The damage that these bacteria do does not usually come from the infection itself but the toxin they can produce. ANDInitial symptoms include a sore throat and a low-grade fever. Within days, the toxin can kill enough cells along the throat and cause revealing granulationYish accumulation of dead debris that makes it difficult for victims to breathe. Sufferers may also develop a swollen “bull’s neck” caused by enlarged lymph nodes. If left untreated, the toxin can seep into the bloodstream and other organs, causing massive internal damage that kills about half of its victims.
Although diphtheria has killed people for centuries, the emergence of antitoxins, antibiotics and a highly effective vaccine in the first half of the 20th century has largely neutralized it. From 1980 to 2000, following the World Health Organization’s push for universal childhood vaccination in the 1970s, the incidence of new annual cases of diphtheria have dropped by more than 90%. Today, about 85% of the world’s population is vaccinated against diphtheria, and the disease is virtually extinct in many countries, including the USA
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There are still pockets in the world where access to effective treatments and vaccines is more limited, Yet. The incidence of diphtheria has also started to increase gradually recently. Ia new study Published On Monday at Nature Communications, scientists say there is evidence that diphtheria bacteria are at risk of genetically changing enough to weaken the effectiveness of antibiotics and vaccines used against them.
The study, which involved researchers from the United Kingdom, India and the World Health Organization, analyzed the genetic diversity of these bacteria (strains producing toxins and non-toxins) over the past century, studying samples collected from patients in 16 countries. This included India, where most annual cases of diphtheria occur. They used this data to trace the evolution of these bacteria over time.
There are signs that the bacteria are beginning to adapt to our weapons, the researchers found. They found a substantial increase in the average number of antimicrobial resistance genes carried by the diphtheria bacterium in the past decade, compared to previous decades. The diversity of its “tox” gene, responsible for producing the deadly toxin has also increased recently. They identified 18 different variants of the tox gene, some of which could alter the basic structure of the toxin, which could make existing treatments less effective..
Antibiotic-resistant strains of diphtheria bacteria can also make it difficult for doctors to treat infections. Meanwhile, the diphtheria vaccine works by training the body to recognize the toxin specifically. ONEAny significant change in its structure can weaken how well our immune system will defend it, as well as the strength of the antitoxin drugs. That said, these findings do not show that diphtheria is now immune to antibiotics or vaccines. The mutations found in your tox gene do not appear to affect the effectiveness of our current vaccine, although there were no evidence of substantial resistance to the most common antibiotics used to treat infections.
The growing diversity of these bacteria suggests that one day it could “learn” how to better escape from our vaccines, antitoxins and antibiotics. And in the context of current trends, this is definitely worrying. In 2018, there were more than 16,000 cases of diphtheria reported worldwide – the highest annual number of deaths seen in 22 years –and 2019 was balanced worst. And last year, the covid-19 pandemic halted vaccination efforts for diseases like diphtheria.
Even in the worst case, vaccines and antitoxins can be modified if necessary, and there are other antibiotics that doctors can use if theremedies for these still-rare infections also begin to fail. But the researchers warn that we must continue to study and start preparing for these possibilities now, before it is too late and diphtheria follows in the footsteps of other vaccine-preventable diseases, such as measles, which caused a scary resurgence recently.
“[I]It is more important than ever to understand this historically important disease, to prevent it from becoming a major global threat again in its original or modified form, better adapted ”, wrote the authors.