salmonella
A link has been found between salmonella, which causes food poisoning, and HIV, leading scientists to believe that the discovery could lead to a salmonella vaccine.
In a study published in the journal Science, scientists explain what appears to be a link between HIV infections and susceptibility to the life-threatening non-typhoidal strains of salmonella, or NTS.
Symptoms of NTS include vomiting and diarrhea. NTS is predominantly contracted in developed countries through the consumption of infected foods, including uncooked meat and eggs.
NTS can lead to fatal bloodstream infections in people who have compromised immune systems, such as those infected with HIV, and in children under the age of two who have malaria, anemia or malnutrition.
"The association between HIV infection and fatal cases of non-typhoidal salmonella disease has been known since the onset of the AIDS pandemic 26 years ago, but this is the first time we’ve been able to offer a scientific explanation," the University of Birmingham’s Dr. Cal MacLennan, who lead the research, told Netdoctor.co.uk.
The research, which was funded by the Wellcome Trust and GlaxoSmithKline, examined why a lack of antibodies caused by HIV could account for the absence of killing and explain why adults infected with HIV are particularly susceptible to salmonella infections.
The team found, contrary to expectations, that blood from HIV infected adults held high levels of antibodies to fight salmonella. The antibodies, unlike those in healthy adults, were not able to kill salmonella. Antibodies from these patients actually stopped healthy adults’ antibodies from killing salmonella.
"We normally think of HIV patients as being more susceptible to bacterial infections because of deficiencies in their immune systems, and often they have problems making antibodies when given vaccinations," Dr. MacLennan said. "In the present study, we found that it’s actually an excess of antibodies that causes the problem.
"The findings are important because LPS [lipopolysaccharide] is currently being investigated as a potential target for a vaccine. Our observations that antibodies targeting LPS can actually impede the protective immune response to salmonella would caution against this, suggesting that such a vaccine could do more harm than good."