Typhoid could be the next medical crisis in store for the UK, as the ancient illness is building a resistance to the medication that treats it.
The highly contagious bacterial infection has been around for more than 1,000 years and antibiotics are the only way to effectively treat Typhoid.
But researchers say the Typhoid bacterium is evolving to become more drug-resistant, Wales Online reports.
Earlier this week, Polio was detected in Britain for the first time in ten years, with experts declaring a national incident.
Salmonella enterica serovar Typhi (S Typhi),the bacterium that causes Typhoid, has reportedly been building up its resistance to oral antibiotics for the last 30 years.
After sequencing genomes of 3,489 different S Typhi strains contracted from 2014 to 2019 in Nepal, Bangladesh, Pakistan, and India, experts found that one strain particular strain was very resistant.
Called (XDR) Typhi, it is not only resistant to trademark antibiotics such as ampicillin and chloramphenicol, but is also building up a resilience to newer drugs too.
These include treatments such as fluoroquinolones and third-generation cephalosporins.
XDR Typhi cases are on the rise globally and while it is mainly found in Asia, health chiefs have warned it represents a global threat, including to the UK.
The World Health Organisation (WHO) has designated antibiotic resistance as a global health emergency.
Jason Andrews, an infectious disease specialist from Stanford University in the US, said: "The speed at which highly-resistant strains of S Typhi have emerged and spread in recent years is a real cause for concern.
It highlights the need to urgently expand prevention measures, particularly in countries at greatest risk."
The latest development follows the discovery of a typhoid "superbug" in 2018 which was found to be resistant to five types of antibiotics.
At least one travel-related case of the bug was detected in the UK after an epidemic started spreading in Pakistan.
The first XDR typhoid strain was identified in Pakistan in 2016, and by 2019, the strain became the dominant genotype in the nation.
It has become so resistant to antibiotics that only one, called azithromycin, can treat it, and mutations which have built up resistance to this drug are now spreading.
In a study on the spread of antibiotic-resistant typhoid strains published in the medical journal Lancet, a team of international authors warned that this is "threatening the efficacy of all oral antimicrobials for typhoid treatment".
They added: "The recent emergence of XDR and azithromycin-resistant S Typhi creates greater urgency for rapidly expanding prevention measures, including use of typhoid conjugate vaccines in typhoid-endemic countries.
"Such measures are needed in countries where antimicrobial resistance prevalence among S Typhi isolates is currently high, but given the propensity for international spread, should not be restricted to such settings."
Up to 70 per cent of typhoid cases come from South Asia, but as the illness is an infection it is easily possible for the disease to be brought over from abroad. In the UK, around 300 infections are confirmed each year, according to the NHS.
The NHS reports that most of these people became infected while visiting relatives in Bangladesh, India or Pakistan. But travellers to other parts of Asia, Africa and South America are also at risk.
While typhoid vaccines are available in the UK, Dr Rumina Hasan, a pathology professor at the Aga Khan University in Pakistan, warned: "Antibiotic resistance is a threat to all of modern medicine and the scary part is we are out of options."
According to the WHO, around 21 million people contract typhoid each year, and it kills 161,000.
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