The disease that doctors at first thought was lung cancer was likely carried on a speck of dust.
一道本不卡免费高清A few years ago, Kevin Pierce, a laconic retired sheriff who has lived his whole life in the Central Valley of California, went to see his family physician about some chest pains. An X-ray showed several nodules in his lungs, suggestive of a spreading cancer – not entirely surprising since Pierce is a smoker. He was referred to for treatment.
一道本不卡免费高清But when the doctors there investigated further, they realized the nodules in his lungs were not from cancer but from a fungal infection.
Pierce had Valley Fever, an illness caused by the fungus Coccidioides immitis, which grows in the hot, dry soil of the Central Valley and across the American Southwest.
“It’s hard to be a doctor in Fresno and not have to deal with Valley Fever,” said , MD, a pulmonologist and associate dean at UCSF Fresno. In fact, Peterson said in his clinic’s experience, up to one-third of patients who are sent for biopsy to confirm lung cancer turn out instead to have Valley Fever., MD, PhD, a microbiologist at UC San Francisco is working to crack this central mystery of Coccidioides: why the fungus makes some people so sick and not others.
To do so, she said, we must first learn a lot more about the basic biology of the fungus and how it behaves inside a host. “We actually know much less about fungal pathogens than we do about other types of microbial pathogens,” she said.
Coccidioides immitis evolved in the Americas long before humans arrived in the New World. It evolved to infect small mammals, like rodents, which may have served as precious sources of food and water in the desert. As more humans moved into these hot arid regions, farming and building in the dusty soil, the fungus infected us, too. It is one of a class of soil fungi known to cause disease and to shape-shift inside a host. In its spherule phase, the fungus is larger than the immune cells that would normally take up and destroy harmful microbes.
一道本不卡免费高清“When they're in the environment of the human body, these fungi really alter their growth program dramatically, and they become attuned to manipulating the human immune response and are really very good at surviving long-term in the human body,” said Sil.
To study how Coccidioides immitis一道本不卡免费高清 undergoes its striking transformation, Sil’s lab is comparing samples of the fungus in its environmental form to samples of the fungus in its parasitic spherule phase.
They hope to identify the changes in gene expression that trigger the transition and also how the fungus interacts with immune cells. “Maybe having a more effective immune response, that could be one of the best weapons we could have to fight infection.”
“We want to do some fundamental research on the fungus, filling in some of our gaps in the knowledge that will ultimately impact prevention, diagnosis, and therapeutics,” said Sil.
Studying a fungus that could potentially be deadly means the researchers take no chances when handling it. Sil’s team at UCSF works with the fungus in a new, state-of-the-art Biosafety Level 3 (BSL-3) laboratory where the air is filtered completely about once a minute and every piece of equipment, even the Sharpies used to label test tubes, is sprayed down with bleach. Researchers must wear full-body protective suits with an attached air-purifying respirator, booties and two layers of gloves. No one works in the lab alone.
These precautions are necessary because the fungus infects easily through inhalation and can make even healthy people sick, said Sil.
一道本不卡免费高清“It's critical then to protect laboratory personnel from infection because any individual could be susceptible to infection with Coccidioides.”.
一道本不卡免费高清A recent makes a grim prediction: by 2100, a warming climate will allow Valley Fever to expand throughout much of the western United States.
Even now, the fungus is almost certainly more widespread than the recorded cases. Researchers estimate that only 60 percent of infected people show symptoms. Some studies estimate that a quarter of community-acquired pneumonia in Arizona are actually Valley Fever. That means tens of thousands more people may be infected with Coccidioides immitis without knowing it.
Increasing infections will have health and financial impacts. A recent estimated that the average lifetime cost for a person diagnosed with Valley Fever approaches $94,000. For the 7,466 Californians who were diagnosed with Valley Fever in 2017, that will total nearly $700 million over their lifetimes.
Californians diagnosed with Valley Fever in 2017
Lifetime financial impacts for those diagnosed
一道本不卡免费高清On New Year’s day 2012, Rob Purdie of Bakersfield woke up with a pounding headache that would not go away. Two courses of antibiotics and headache medication did nothing to help and, for weeks, Purdie could do little but lie in bed in a dark room. “It consumed my life. Twenty-four hours a day for six weeks, I had one thing on my mind and it was how bad my head hurt,” he said.
Finally, a lumbar puncture confirmed that he had meningitis caused by Valley Fever. He thinks he might have picked up a spore doing yardwork in his backyard. He was put on strong doses of antifungal drugs and eventually required a port on his head to directly deliver the drugs into his brain. Some of the antifungal drugs have made his skin more sun-sensitive so he’s also had to deal with several bouts of skin cancer, and he will likely require the drugs for the rest of his life.
一道本不卡免费高清“What I want people to know is, if you live or travel though the Southwestern United States – Vegas or Arizona or Bakersfield or L.A. or wherever – you’re not going to travel through that part of the country without potentially coming in contact with Valley Fever,” said Purdie.
Harrowing stories like Purdie’s are raising awareness of the need for more research into Valley Fever. The disease carried on specks of dust is finally gaining attention from state officials. Last year, California approved $8 million to boost Valley Fever research and outreach, of which $3 million will go toward research across the University of California system, including the work in Sil’s lab.
“Valley Fever is very much a growing problem, and we need to be able to counteract it more effectively than we can now,” said Sil.“We have a long way to go before we’re at that point, but we hope that the knowledge we uncover will lead to new strategies to fight these infections.”