Novel Pathogen Epidemic Identified in Sub-Saharan Africa:

The spread of human an invasive chloramphenicol resistant Salmonella Typhimurium is the causative agent.

Researchers have found that the spread of a dangerous pathogen that can be fatal in up to 45% of people infected in sub-Sahara Africa may have been instigated by the emergence and spread of HIV in Africa. The study also found that one of the major contributing factors for the successful spread of the disease -- non-Typhoidal Salmonella (iNTS) -- was the acquisition of genes that afford resistance to several front line drugs used to treat blood-borne infection such as iNTS.

A new study out September 30 reveals that the emergence and spread of a rapidly evolving invasive intestinal disease, that has a significant mortality rate (up to 45%) in infected people in sub-Saharan Africa, seems to have been potentiated by the HIV epidemic in Africa.

The team found that invasive non-Typhoidal Salmonella (iNTS) disease is caused by a new form of the bacteria Salmonella Typhimurium that has spread from two different focal hubs in Southern and Central Africa beginning 52 and 35 years ago, respectively. They also found that one of the major contributing factors for the successful spread of iNTS was the acquisition of genes that afford resistance to several front line drugs used to treat blood-borne infection such as iNTS.

iNTS is a blood-borne infection that kills approximately one of four people in sub-Saharan Africa who catch it. Yet, in the rest of the world, NTS is a leading cause of acute inflammatory diarrhea that is self-limiting and tends to be fatal in less than 1 per cent of people infected. The disease is more severe in sub-Saharan Africa than the rest of the world because of factors such as malnutrition, co-infection with malaria or HIV and potentially the novel genotype of the Salmonella bacteria.

"The immune system susceptibility provided by HIV, malaria and malnutrition at a young age, may provide a population in sub-Saharan Africa that is large enough for this detrimental pathogen to enter, adapt, circulate and thrive," says Chinyere Okoro, joint first author from the Wellcome Trust Sanger Institute. "We used whole genome sequencing to define a novel lineage of Salmonella Typhimurium that is causing a previously unrecognised epidemic across the region. Its genetic makeup is evolving into a more typhoid like bacteria, able to efficiently spread around the human body"

"Because it acquired resistance to chloramphenicol, this pathogen has much greater opportunity to survive and spread across the region," says Professor Gordon Dougan, lead author from the Wellcome Trust Sanger Institute. "This is the first time that the power of whole-genome sequencing has been used to track the spread of iNTS. Our research highlights the power this approach has to monitor the emergence and spread of dangerous pathogens both locally and globally over time."

Source: www.sanger.ac.uk/about/press/.../120930.html