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Trees in public park may be source of cryptococcal infection in South Africa
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Researchers identified large populations of Cryptococcus neoformans and C. gattii — two fungi that cause substantial morbidity and mortality among patients with HIV — on trees in a public park and game farm in South Africa.
Jo-Marie Vreulink, PhD student in the department of microbiology at Stellenbosch University, and colleagues reported in Fungal Ecology that their findings provide evidence that Cryptococci on trees in South Africa may be causing infections in patients.
According to the researchers, pathogenic Cryptococci have been known to colonize in trees; however, data on the prevalence of Cryptococci in the South African environment are scarce.
Lead study researcher Alf Botha, PhD, professor in the department of microbiology at Stellenbosch University, said in a press release that he has been searching for Cryptococcus in South Africa since 2003. Researchers initially conducted searches in woody debris sampled from pristine areas, according to Vreulink. After increasing evidence showed that Cryptococci are commonly found in areas with pigeons, old trees and people, the researchers began collecting samples in more public spaces. They sampled trees at a public park in Cape Town and a privately owned game farm in the Northern Cape.
Six trees in the public park and one tree at the game farm tested positive for C. neoformans and C. gattii. The majority (80%) of isolates from trees in the public park were C. gattii, which the researchers described as “surprising” because this species was isolated from the environment in South Africa only once before.
“Considering that members of the C. gattii species complex are emerging in regions with a Mediterranean climate, the C. gattii sensu stricto population in the public park might pose a risk to human health,” they wrote. “It is, therefore, clear that more environmental, clinical and sentinel studies should be conducted in South Africa to monitor any emerging trend of this and related species.”
After further investigation, the researchers found that C. neoformans isolated from trees in the park matched a clinical isolate from a patient treated a Western Cape hospital, indicating that trees in the area may be a source of infection.
“At the moment, my research is generating more questions than answers,” Vreulink said in the release. “For now, I’m focusing on the ecology of these yeasts. I want to understand the population dynamics, the genetics and how these interact with their environment. If we can understand how they survive out there, we can use this knowledge to better predict how they can survive in their human host.” – by Stephanie Viguers
Disclosures: Infectious Disease News was unable to confirm relevant financial disclosures at the time of publication.
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