Two common fungi found on food in developing countries could be worsening the effects of HIV, say researchers from the University of Alabama, Birmingham.

Their study, published in the World Mycotoxin Journal, found that types of fungus on stored foods such as rice, wheat, nuts and corn, are linked to higher HIV viral loads (higher concentrations of the virus in infected people’s blood).

The researchers say:

Higher viral load translates into higher rates of HIV transmission and the potential for earlier progression to the opportunistic infections of AIDS.”

According to the researchers, foods that are stored in warehouses and barns of developing countries near the equator, such as Asia and Africa, become contaminated by Aspergillus flavus and A. parasiticus.

Because these fungi produce aflatoxin, a poisonous substance that has been known to cause cancer and liver damage in humans and animals, the Food and Drug Administration (FDA) has imposed regulations on the levels of the toxin in US food – particularly in animal feeds.

There are no similar restrictions on the levels of this toxin in developing countries, meaning citizens are much more likely to be exposed to high levels of the fungi and aflatoxin.

The researchers say around 4.5 billion people worldwide are exposed to unsafe levels of aflatoxin.

For the study, 314 HIV-positive people were recruited who had not yet started antiretroviral treatment for the infection.

Patients were split into four groups dependent on their levels of exposure to aflatoxin.

HIV-infected people subjected to the highest exposure of aflatoxin were 2.6 times more likely to develop a higher HIV viral load than those in the lowest-exposure group.

Pauline Jolly, professor in epidemiology at the University of Alabama’s School of Public Health, says:

“Our work suggests that aflatoxin exposure may be taking an even greater toll in areas where millions are infected with HIV, including Africa and Asia, the latter with a fast-growing HIV population and rice storage areas contaminated by fungi.”

Prof. Jolly adds that the team conducted previous studies focusing on the link between the progression of HIV and interaction with aflatoxin, but the current study analyzed twice as many patients.

For the first time, this study also eliminated factors such as opportunistic infections and antiviral therapy to determine the relationship between HIV and aflatoxin exposure.

Prof. Jolly notes that although studies have shown a link between aflatoxin exposure and HIV infection, the issue has not yet been recognized or addressed.

She says:

While this study was larger than our previous study, a fungal contribution to HIV transmission will only be proved once and for all by larger randomized studies for which there is no funding.

The scientific and world-health communities need to decide soon whether or not this question is worth answering.”