A devastating Salmonella epidemic is ravaging parts of sub-Saharan Africa right now — and it appears that HIV gave this rapidly evolving form of Salmonella a major boost. According to a new study, the African HIV epidemic appears to have provided this strain of Salmonella with a large number of humans with weakened immune systems, giving it a place to evolve, and to spread rapidly.
Worse still: the new, improved strain of Salmonella doesn't respond to the first set of antibiotics, meaning that doctors have to use more expensive drugs, instead. Just one more way that HIV is more evil than we ever knew.
Called non-Typhoidal Salmonella (iNTS), the relatively new disease was generated by a new form of the bacteria Salmonella typhimurium that spread from two different focal hubs in Southern and Central Africa. It emerged in two separate waves, the first in 1960 and the second in 1977 (possibly from the Congo Basin).
iNTS is a blood-borne infection that kills 25% to 45% of Sub-Saharan Africans who contract it. In other parts of the world, NTS is fatal in less than 1% of people infected. The disease appears to be more severe in Africa, on account of such factors as malnutrition, co-infection with malaria or HIV — and possibly also, the new mutated version of the Salmonella bacteria.
In a new study, researchers analyzed the pathogen's genetic makeup and found that it is evolving into a more typhoid-like bacteria, that is able to efficiently spread around the human body.
And indeed, it was this perfect storm of factors — HIV, malaria, and malnutrition — that has allowed this disease to enter, adapt, circulate, and thrive. The researchers tracked its spread over the past 50 years from the Congo to the northern Sub-Saharan regions as it came into contact with susceptible populations.
In addition to this, the researchers also found that one of the major contributing factors for the successful spread of iNTS is that it developed a resistance to several front line drugs used to treat blood-borne infections such as iNTS.
On a positive note, the study marks the first time that whole-genome sequencing was used to track the spread of iNTS — an important bit of insight that may allow the researchers to determine how NTS is actually transmitted in sub-Saharan Africa, something that still remains a mystery (though some evidence exists that it may be passed on from human to human).
You can read the entire study at Nature Genetics.
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