Date Published: 11 October 2012
Scientists link HIV with Salmonella epidemic in sub Saharan Africa
Scientists have recently reported the emergence and spread of a deadly strain of Salmonella. According to researchers at Liverpool University, England, Salmonella Typhimurium has been associated with the HIV virus in parts of sub-Saharan Africa.
The scientists tracked the spread of invasive Non-Typhoidal Salmonella (iNTS) in sub-Saharan Africa, where it reports indicate that it kills 25% of people who catch it. They found that the emergence and spread of the deadly version of this intestinal bacteria is closely associated with Africa's HIV epidemic.
The research team sequenced the DNA of 179 samples of Salmonella strains from across Africa. They found that new strains of the bacterium emerged in two waves and in two locations. The first started in south-eastern Africa about 52 years ago and the second wave started 35 years ago in the Congo Basin - the Congo region of Africa including many countries (in whole or in part), specifically Angola, Cameroon, the Central African Republic, the Democratic Republic of the Congo, the Republic of the Congo (also known as Congo-Brazzaville and simply as Congo), Burundi, Rwanda, Tanzania and Zambia.
Dr Melita Gordon, from the University's Institute of Translational Medicine said:
" We found that the emergence and spread of new variants of Salmonella Typhimurium mirrors the emergence of HIV in Africa. These strains seem to be quite unique to Africa. This is the first time we have demonstrated the spread of a variant right across the continent, associated with HIV.
_ HIV attacks the immune system and leaves people more vulnerable to other infections. It looks like the bacterium was able to enter, adapt, circulate and thrive in the people whose immune systems were weakened by the HIV virus. Hopefully, improving HIV treatment across Africa will reduce the prevalence of this infection."
The researchers found that another major contributing factor for the increased spread of the new strains of Salmonella Typhimurium was that the bacteria had become resistant to the antibiotics used to treat them.
Outside Africa, Salmonella Typhimurium causes gastroenteritis and diarrhoea (see also causes of diarrhoea) but is only fatal in less than 1% of healthy people infected. In sub-Saharan Africa the infection poses a much more serious health threat, invading into the blood stream and having a mortality rate of 25% or more among those with HIV, malnutrition, or malaria.
The newly-evolved strain of Salmonella has been recognised in Africa since 2009 but this new work has provided evidence that it is a single epidemic causing deaths right across the continent.
Ref. to Paper:
"Intracontinental spread of human invasive Salmonella Typhimurium pathovariants in sub-Saharan Africa", C K Okoro et.al. Nature Genetics, Pub. 30 Sept 2012, doi:10.1038/ng.2423
Main source: Liverpool University