"The only things we have to go by are the actual health data," said James Tamerius, a postdoctoral researcher in environmental health sciences at the Mailman School of Public Health at Columbia University. Based on this information, he noted, some patterns have started to emerge.
Tamerius explained that heavy fall and winter precipitation preceded previous spikes in valley fever by a year or so. He also noted that the disease tends to cluster near swaths of desert. "These big, open environments are what's necessary," he said. Cases also emerge as the dust is perturbed, often on construction sites and sometimes from dust storms that occasionally blanket the region.
As for the climate, Tamerius said it is hard to tell if warming temperatures are having an effect on the increases in the disease. "Some people think it has to do with changes in climate. Some people think it has to do with people moving in from out of state," he said, noting that previously unexposed people, like retirees settling down in Phoenix, may be at greater risk. The Centers for Disease Control and Prevention notes on its valley fever website that 30 to 60 percent of people who live in endemic regions are exposed to the fungi at some point in their lives. Better surveillance, awareness and reporting may also be pushing numbers higher.
Researchers are concerned because there is no reliable way to anticipate a surge or outbreak, or even increased risk for the disease. "There's not enough ecological data at the sub-meter scale to make those predictions," Tabor said. Valley fever's regional impacts also make it harder for local officials to garner national attention and research support.
For now, health officials are pinning their hopes on a vaccine to push back against dust clouds of infection. "This is a disease that's very hard to prevent because you can't tell people not to breathe," Tsang said.
Reprinted from Climatewire with permission from Environment & Energy Publishing, LLC. www.eenews.net, 202-628-6500