A boy infected by typhoid from polluted water, lies at a hospital in al-Qouniya village in Idlib countryside, May 27, 2013. 
 
 LONDON An antibiotic-resistant "superbug" strain of typhoid fever has spread globally, driven by a single family of the bacteria, called H58, according to the findings of a large international study. 
 
 The research, involving some 74 scientists in almost two dozen countries, is one of the most comprehensive sets of genetic data on a human infectious agent and paints a worrying scene of an "ever-increasing public health threat", they said. 
 
 Typhoid is contracted by drinking or eating contaminated matter and symptoms include nausea, fever, abdominal pain and pink spots on the chest. Untreated, the disease can lead to complications in the gut and head, which may prove fatal in up to 20 percent of patients. 
 
 Vaccines are available -- although, due to limited cost effectiveness, not widely used in poorer countries -- and regular strains of the infection can be treated with antibiotic drugs. However, this study found that the H58 "superbug" version, which is resistant to multiple types of antibiotics, is now becoming dominant. 
 
 "H58 is displacing other typhoid strains, completely transforming the genetic architecture of the disease and creating a previously under appreciated and on-going epidemic," the researchers said in a statement about their findings. 
 
 Vanessa Wong of Britain's Wellcome Trust Sanger Institute, who was part of the international team, said that since typhoid affects around 30 million people a year, robust and detailed good global surveillance is critical to trying to contain it. 
 
 The research team, whose work was published in the journal Nature Genetics on Monday, sequenced the genomes of 1,832 samples of Salmonella Typhi bacteria that were collected from 63 countries between 1992 and 2013. 
 
 They found 47 percent were from the H58 strain. 
 
 DON'T MISS THESE OTHER STORIES ON REUTERS.COM 
 
 Hundreds of refugees arrive in Malaysia and Indonesia after Thai crackdown 
 
 Why NSA surveillance is worse than you’ve ever imagined 
 
 
 
 The team found that H58 emerged in South Asia 25 to 30 years ago and spread to Southeast Asia, Western Asia, East and South Africa and Fiji. They also found evidence of a recent and unreported wave of H58 transmission in many countries in Africa, which may represent an ongoing epidemic. 
 
 Kathryn Holt, a scientist at the University of Melbourne in Australia who worked on the study, said multidrug resistant typhoid is caused by the bacteria picking up new resistance genes as disease strains mix and pass from person to person. 
 
 Resistance "has been coming and going since the 1970s", she said, but in the H58 strain, the resistance genes are becoming a stable part of the genome "which means multiple antibiotic resistant typhoid is here to stay". 
 
 (Editing by Crispian Balmer/Hugh Lawson) 

 An antibiotic-resistant strain of the bacteria that causes typhoid fever has spread to many countries and reached epidemic levels in Africa, a new study warns. 
 
 The strain, H58, emerged in South Asia between 25 and 30 years ago and has slowly grown to become one of the predominant forms of the bacteria Salmonella Typhi, said study author Vanessa Wong, a microbiologist at the University of Cambridge in England. 
 
 "This multidrug-resistant strain, H58, is resistant to a number of first-line antibiotics used to treat the disease and is continuing to evolve and acquire new mutations to newer drugs," Wong said. 
 
 Typhoid presents no direct threat to people living in the United States, where clean water supplies and good sanitation prevent exposure to the bacteria, said Dr. Henry Chambers, chief of infectious diseases at San Francisco General Hospital and a professor at the University of California, San Francisco. 
 
 But travelers headed to typhoid-ridden parts of Africa and Asia should make sure they receive a vaccination before heading there, Chambers added. 
 
 Dr. Wanda Filer, president-elect of the American Academy of Family Physicians, agreed. 
 
 "We recommend that people who are traveling to parts of the world where [typhoid] is endemic get the typhoid vaccine," Filer said, adding that the vaccine is 50 percent to 80 percent effective against all strains of typhoid, even those that have become antibiotic-resistant. 
 
 Typhoid fever affects between 20 million and 30 million people around the globe each year, the researchers said. 
 
 Symptoms include a high, sustained fever, weakness, stomach pains, headache and loss of appetite. As many as 20 percent of patients may die from complications associated with typhoid infection, which can last for weeks or months without proper treatment, according to the U.S. Centers for Disease Control and Prevention. 
 
 People contract typhoid when they eat food or drink beverages that have been contaminated with the bacteria, according to the CDC. Someone infected with S. Typhi can pass it on by handling food or drinks. Or, water used for drinking or washing food might become contaminated with sewage containing the bacteria. 
 
 In this study, a multinational team of researchers used genetic sequencing to track the spread of antibiotic-resistant typhoid. 
 
 The research team found that the H58 strain has displaced other typhoid fever strains that have endured for decades or even centuries. H58 was identified in nearly half of more than 1,800 bacteria samples collected from 63 countries between 1992 and 2013. 
 
 After the H58 strain emerged in South Asia more than two decades ago, it spread to Southeast Asia, Western Asia, East and South Africa and Fiji, the researchers reported. 
 
 They also found evidence of a recent and unreported wave of H58 transmission in multiple countries in Africa, which may represent an ongoing epidemic. 
 
 Tactics used to fight typhoid in these countries appear to have led to increased antibiotic resistance, Wong said. 
 
 "Vaccinations are not currently in widespread use in typhoid-endemic countries," she said. "Instead, antibiotics are commonly used as a preventive measure. As a consequence, there is a rise in antibiotic resistance to many pathogens and in particular a resurgence of multidrug-resistant typhoid has been observed in some areas, including parts of Africa." 
 
 Their findings were published online May 11 in the journal Nature Genetics. 
 
 Americans who travel to a country that has typhoid should get vaccinated and then monitor their temperature in the weeks following their return home, he said. If they do develop a fever, they should tell their doctor about their travels. 
 
 "It would be important to tell your doctor that you've been to one of those areas, because then certain antibiotics you would normally use would not be effective," he said. "There already are guidelines to use antibiotics that work against the more drug-resistant strains." 

 Image copyright CDC/ Melissa Brower/SCIENCE PHOTO LIBRARY 
 
 Antibiotic-resistant typhoid is spreading across Africa and Asia and poses a major global health threat, warn experts. 
 
 Researchers from the Wellcome Trust, who have been tracking the hard-to-treat infection, say it is replacing regular typhoid in many countries. 
 
 They analysed bacterial samples from 63 countries - nearly half were impervious to standard antibiotic treatments. 
 
 Over-reliance on these drugs is to blame, they say in Nature Genetics. 
 
 Increasingly, doctors now need to use other, more expensive and less readily available antibiotics to treat typhoid fever - a disease that kills around 200,000 people each year. 
 
 Creeping resistance 
 
 The Wellcome Trust work is the largest snapshot of what is happening globally to typhoid resistance. 
 
 It shows the problem is widespread. 
 
 In many parts of Asia and Africa, where typhoid is endemic, a multidrug-resistant strain of typhoid called H58 has displaced other typhoid strains that have been around for centuries. 
 
 Of the 63 countries the researchers looked at, 21 had H58. 
 
 Image copyright Science Photo Library Image caption Typhoid growing in the lab 
 
 Dr Kathryn Holt, from the University of Melbourne and one of the study authors, said H58 was gaining a firm foothold. 
 
 "Multidrug-resistant typhoid has been coming and going since the 1970s and is caused by the bacteria picking up novel antimicrobial resistance genes, which are usually lost when we switch to a new drug. 
 
 "In H58, these genes are becoming a stable part of the genome, which means multiple-antibiotic resistant typhoid is here to stay." 
 
 The researchers say the global creep of H58 needs urgent international attention. 
 
 A third of the world's population is at risk of getting typhoid. 
 
 It is caused by the highly contagious bacterium Salmonella typhi, spread from person to person by food and water that is contaminated with traces of infected faeces or urine. 
 
 Improved water, sanitation and hygiene could dramatically cut the number of infections, but the investment needed to do this may be our of reach for many developing countries. 
 
 There are vaccines against typhoid, but they are not available in all parts of the world, nor are they 100% protective. 
 
 A spokeswoman for the World Health Organization said: "Limiting the inappropriate use of antibiotics is part of the solution, and surveillance systems to identify antibiotic-resistant bacteria need to be improved to identify hotspots and intensify prevention and control measures."
– Efforts to fight typhoid in some of the world's poorest countries have helped create an antibiotic-resistant "superbug" strain of the disease that's spreading worldwide, researchers warn. According to a study published in Nature Genetics, the resistant H58 strain of typhoid is now present in at least 21 countries, mainly in Africa and Asia, where it has displaced older and more easily treated forms of the bacteria, the BBC reports. The researchers, who looked at bacteria samples collected from 63 countries over more than 20 years, warn that H58 is "completely transforming the genetic architecture of the disease and creating a previously under-appreciated and ongoing epidemic," Reuters reports. The researchers say the H58 strain started to spread from South Asia around 30 years ago and is making it much tougher for doctors to treat typhoid, which is spread through contaminated food and water and kills around 200,000 people a year. In countries where typhoid is endemic, vaccines aren't widely used but "antibiotics are commonly used as a preventive measure. As a consequence, there is a rise in antibiotic resistance to many pathogens and in particular a resurgence of multidrug-resistant typhoid," study author Vanessa Wong tells CBS, which notes that while Americans are at little risk from the disease at home, experts recommend they be vaccinated before traveling to at-risk areas. (Liberia is now Ebola-free—but it's experiencing a related surge in measles cases.)