Salmonella Food Poisoning and HIV
Salmonella infection is never pleasant, but for most healthy people who are exposed to the bacteria suffer from gastroenteritis and recover. For patients with AIDS, however, the same bacteria that result in uncomfortable food poisoning for most is often fatal. Scientists from the UC Davis Medical School have discovered what mechanisms the HIV virus uses that allow for the lethal aspects of Salmonella.
According to Science Daily,
The results of the study, which will be published online by Nature Medicine March 23, revealed that viral infection of the intestine results in the depletion of a type of white blood cell, called Th-17, in the gut mucosa. This T helper lymphocyte produces IL-17, a cytokine or chemical messenger that plays a crucial role in the inflammatory response, recruiting other immune system cells to the site of infection.
In healthy patients, the bacterial infection is defeated in the gut, but with AIDS patients, this battle is lost and the infection spreads into the bloodstream. When the Salmonella spreads to the bloodstream, it is known as NTS bacteremia.
The scientist tested their theory by examining rhesus macaques infected with simian immunodeficiency virus (SIV), a model for HIV. The animals that were not infected with SIV were able to combat infection by producing Th-17 cells in huge amounts, whereas those with SIV were unable to do so.
The team of researchers also used mice that lacked the IL-17 receptor, an arm of the mucosal immune response, to confirm that IL-17 deficiency leads to increased systemic dissemination of Salmonella.
By narrowing down the mechanisms and pathways and understanding how Salmonella can become in fatal in the growing number of individuals who have AIDS, scientists will hopefully be able to curb the number of fatalities. Future research will examine more specifically how healthy patients are able to get rid of Salmonella infection in the gut and apply what they learn to decrease the mortality rate from Salmonella poisoning in AIDS patients.