A variety of typhoid fever, highly resistant to antibiotics, is spreading around the world, according to a new study.
The outbreak may have already reached epidemic proportions in Africa. The H58 family of bacteria, a drug-resistant form of the microorganism responsible for the illness, is now beginning to infect people around the world, according to a new study.
A team of 74 researchers in 12 nations examined the spread of the bacteria as well as its effects on human beings. More than 1,800 samples of Salmonella typhi collected from 63 nations were examined as part of the study, and 47 percent of these bacteria were found to be of the H58 variety that has health care workers so concerned.
"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 multiply antibiotic-resistant typhoid is here to stay," Kathryn Holt of the University of Melbourne, said.
Typhoid fever is contracted through the consumption of food or drink contaminated with the feces of human beings. The illness strikes about 30 million people around the world each year, producing symptoms that include fever, nausea, abdominal pain and pink marks. People infected often experience additional problems in the abdomen and head.
Treatment of the disease is possible, but roughly one in five people who are left untreated will die from the infection. Simple strains of the bacteria can be treated with antibiotics, but vaccines are rare in poorer nations due to the cost of manufacturing and delivering the drugs.
"H58 is displacing other typhoid strains, completely transforming the genetic architecture of the disease and creating a previously under appreciated and on-going epidemic," researchers wrote in a statement announcing their investigation.
Biologists believe the H58 strain of the bacteria may have first evolved 25 to 30 years ago in south Asia before spreading to the southeast of that continent. From there, H58 likely traveled to western Asia, southern and eastern Africa and then on to Fiji. On the African continent, which is finally recovering from the world's worst outbreak of Ebola, transmission is rapid enough to have researchers concerned they may be witnessing a new epidemic. As the bacteria spreads from one person to another, the organisms can acquire resistance to additional drugs, making them harder to treat.
Analysis of H58 and how the antibiotic-resistant form of the bacteria responsible for typhoid fever is infecting human populations was profiled in the journal Nature Genetics.
Photo: The Library of Congress | Flickr
