What a Global Typhoid Outbreak Means for the U.S.

Diseases don't respect borders, the Centers for Disease Control and Prevention likes to remind us. Even with a disease like typhoid, which is somewhat contained to developing countries with poor sanitation, there can be global implications when treatments fail.

So when researchers announced this week that they had mapped a strain that has become resistant to multiple antibiotics, health organizations around the world took note of its widening spread.

"We are limited in our treatment options" since the superbug has become resistant to a number of first-line antibiotics used to treat typhoid, said Dr. Vanessa Wong, an infectious-disease specialist at the Wellcome Trust Sanger Institute in Hinxton, UK, who sequenced the genomes of more than 1,800 Salmonella typhi samples for the study published in Nature Genetics.

"If it continues to develop resistance to newer agents, eventually we'll run out of options."

While it's extremely unlikely that typhoid would rage in country with good sanitation (of the estimated 5,700 cases of typhoid the United States sees annually, the CDC says most are picked up through travel), the resistance of the strain known as H58 has implications far beyond the countries where the disease is common.

The researchers traced the strain, which they found in 47 percent of the typhoid-causing bacteria, to Southeast Asia, Western Asia, East Africa and Fiji. It's also been found in Southern Africa.

Typhoid, which is spread through contaminated food or water, causes fever, headaches, aches and lethargy for 3-4 weeks; if untreated with antibiotics, it has a 20 percent fatality rate.

Ever since typhoid first showed resistance to an antibiotic back in the middle of the 20th century, new drugs have had to replace versions that stopped working. But the problem isn’t just that researchers are running out of new antibiotics for treating typhoid.

Other related diseases could potentially stop responding to antibiotics as well. One common type of traveler's E. coli, for example, is typically treated with antibiotics, said Dr. Eric Mintz, an epidemiologist for CDC’s Division of Foodborne, Waterborne, and Environmental Diseases. If you consider the environment bacteria live in, he said, they can pass around genetic material like peanuts at a cocktail party.

In other words, E. coli could pick up the resistance of the typhoid, making it no longer responsive to antibiotics.

"Having a gene that encodes for resistance in that pool could get to other types of salmonella or E. coli or any other bugs that cause disease," he said.

Read more at Discovery News