Diphtheria threatens to resurface, Cambridge scientists warn. The relatively easily preventable infection is becoming more resistant to various antibiotics and the vaccines are likely to become less effective.
Diphtheria is a highly contagious infection that can affect the nose, throat and sometimes the skin. Left untreated, the disease can be fatal.
In many parts of the world, babies are vaccinated against the infection. In low and middle income countries, the disease continues to cause sporadic outbreaks in unvaccinated and partially vaccinated communities.
The disease has not yet been completely defeated, a new study in the journal warns Nature Communications led by Cambridge University. Worldwide, the number of cases is increasing again. In 2018 there were 16,651 reports. That is more than double the annual average between 1996 and 2017.
The scientists examined the genomes of bacteria all over the world and thus constructed a “genetic” family tree. This shows that the bacterium C. diphtheriae has been present in the human population for more than a century and has spread around the world as the population migrated. The scientists identified eighteen variants of the disease-causing component, the so-called “diphtheria toxin”. That is important, because the vaccine focuses on that variant. “So any genetic variants that change the structure of the toxin can affect how effective that vaccine is,” says Professor Gordon Dougan of the Cambridge Institute of Therapeutic Immunology and Infectious Disease (CITIID).
Resistance
The scientists also found that the bacteria’s resistance to antibiotics increased every decade. “The C. diphtheriae genome is complex and incredibly diverse,” says lead researcher Robert Will. ‘It builds up resistance to antibiotics that are not even used clinically in the treatment of diphtheria. So there are other factors to consider, such as an asymptomatic infection and exposure to all kinds of antibiotics that are intended to treat other diseases. ‘
According to the researchers, covid-19 also plays a role in the fight against diphtheria. The pandemic is hampering childhood vaccination schedules and comes just as the number of reported cases is on the rise. “It’s more important than ever to understand how diphtheria evolves and spreads,” said Ankur Mutreja, who led the study. ‘We must not let our attention get lost with diphtheria, otherwise we run the risk that it will again become a major global threat, possibly in a different, more adapted form.’
Diphtheria is a highly contagious infection that can affect the nose, throat and sometimes the skin. Left untreated, the disease can be fatal, and many parts of the world are vaccinating babies against the infection. In low- and middle-income countries, the disease continues to cause sporadic outbreaks in unvaccinated and partially vaccinated communities.The disease has not yet been fully defeated, warns a new study in the journal Nature Communications led by Cambridge University. Worldwide, the number of cases is increasing again. In 2018 there were 16,651 reports. That is more than double the annual average between 1996 and 2017. The scientists examined the genomes of bacteria all over the world and thus constructed a “genetic” family tree. This shows that the bacterium C. diphtheriae has been present in the human population for more than a century and has spread around the world as the population migrated. The scientists identified eighteen variants of the disease-causing component, the so-called “diphtheria toxin”. That is important, because the vaccine focuses on that variant. “ So any genetic variants that change the structure of the toxin can affect how effective that vaccine is, ” says Professor Gordon Dougan of the Cambridge Institute of Therapeutic Immunology and Infectious Disease (CITIID). of the antibiotic bacteria increased every decade. “The C. diphtheriae genome is complex and incredibly diverse,” says lead researcher Robert Will. ‘It builds up resistance to antibiotics that are not even used clinically in the treatment of diphtheria. So there are other factors to play, such as an asymptomatic infection and exposure to all kinds of antibiotics that are intended for the treatment of other diseases. ‘ According to the researchers, covid-19 also plays a role in the fight against diphtheria. The pandemic is hampering childhood vaccination schedules and comes just as the number of reported cases is on the rise. “It’s more important than ever to understand how diphtheria evolves and spreads,” said Ankur Mutreja, who led the study. ‘We must not let our attention get lost with diphtheria, otherwise we run the risk that it will again become a major global threat, possibly in a different, more adapted form.’
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