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article imageFungus that is deadly to AIDS patients found to live in trees

By Megan Hamilton     Aug 25, 2014 in Health
Los Angeles - It may be small, but for people with AIDS it can be deadly. Researchers have narrowed down the source of fungal infections that have been making people with HIV/AIDS in southern California sick for decades.
Thanks to a 13-year-old girl and her science project, researchers now know that trees harbor the deadly fungus. The girl spent her summer science project collecting samples from soil and local trees in areas that have been particularly hard-hit by the fungus, according to Duke Today.
She swabbed more than 30 species of trees to collect samples of DNA and sent them to Duke for genetic sequencing. A team of researchers found DNA from C. gattii among three of the trees sampled and genetically matched the fungus to strains found previously in Los Angeles AIDS patients, reports News.Sciencemag.org.
There are several species of cryptococcus that cause life-threatening infections of the lungs and brain, and they are responsible for one-third of all deaths related to AIDS.
The study, published in PLOS Pathogens on Aug. 21, found genetic evidence that three species of trees--Canary Island pine, Pohutukawa, and American sweetgum — can serve as hosts for the fungus and provide sources of these human infections, noted Duke Today.
"Just as people who travel to South America are told to be careful about drinking the water, people who visit other areas like California, the Pacific Northwest and Oregon need to be aware that they are at risk for developing a fungal infection, especially if their immune system is compromised," said Deborah J. Springer, Ph.D. Springer is the study's lead author and a postdoctoral fellow at the Center for Microbial Pathogenesis at Duke University School of Medicine.
The project began to blossom a few years ago when Duke university's chairman of Molecular Genetics and Microbiology, Joseph Heitman M.D., was contacted by UCLA infectious disease specialist Scott Filler, M.D. His daughter, Elan, was searching for a summer project. They decided that looking for fungi living in the greater Los Angeles area would be fun, per Duke Today.
She swabbed 109 trees comprising 30 species and 58 soil samples, and then grew and isolated the Cryptococcus fungus. Next, she sent them to Springer at Duke, who DNA-sequenced the samples from California. Springer compared the sequences to those from HIV/AIDS patients with C. gattii infections.
She was surprised by the results. Specimens from three of the tree species were nearly genetically indistinguishable from the specimens provided by patients. The researchers also discovered that the fungus samples isolated from the environment were fertile — reproducing by sexual or asexual reproduction.
"That finding is important for long-term prevalence in the environment, because this fungal pathogen will be able to grow, reproduce, disperse spores, and serve as a source of ongoing infections," Springer said.
The CDC reports that many fungal infections are opportunistic, meaning that they often attack people with weakened immune systems.
CDC recommendations for patients with HIV/AIDS:
• Keep informed about fungal infections. There are many types of fungal infections, and learning about them can help patients to keep their health care providers recognize the symptoms early on.
• Know the risks. The danger of getting one of these infections can vary depending upon where a person lives, and their CD4 count. CD4 cells, or T-cells alert the immune system when they detect viruses or bacteria. Knowing the risks may prevent serious illness.
• Get additional medical care when necessary. Fungal infections frequently resemble other illnesses. Visiting a health care provider can mean a quicker diagnosis and may stop serious illness in its tracks.
• Avoid areas that contain a lot of dust. This can include construction or excavation sites.
• Stay indoors during dust storms.
• Stay away from areas where bird and bat droppings are found — including chicken coops and caves.
• Wear gloves when handling soil, moss, or manure. Patients should also wear shoes, long pants, and a long-sleeved shirt when working in the garden or visiting wooded areas.
• Getting tested early — especially in parts of the world with high rates of HIV/AIDS and where cryptococcosis is common can help detect infection early on, making it easier to provide treatment to keep the infection from becoming deadly.
While cryptococcal diseases are a common killer of HIV-infected people who have weakened immune systems, the advent of potent antiretroviral drugs has fortunately led to a steep decline in its incidence in places where people can access these drugs, News. Sciencemag.org reports.
More about Aids, HIV, Fungus, Cryptococcus gattii, Duke university
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