What has caused the record number of valley fever cases in California?
El Nino and other winter storm phenomena are most likely to blame, according to the best available information on the disease. Stanislaus County’s almond harvest dust is off the hook.
Last year, the state recorded the largest number of valley fever cases since the disease became reportable to public health agencies in 1995. The numbers kept surging this year in counties such as Stanislaus, which has seen more than 50 percent annual increases since 2014.
“We are seeing very many people with valley fever,” said Dr. Demosthenes Pappagianis, associate director of the Coccidioidomycosis Serology Laboratory at UC Davis. “It is probably the greatest occurrence in recorded history on the disease."
The lab and an associated department at UC Davis are leaders in research and care for coccidioidomycosis, the official name of the valley fever fungal lung infection, which also is known as cocci.
Juan Lomeli of Merced came down with the classic signs of cocci in April 2016 – pneumonia and a lumpy rash on his legs. His fevers were constant for a month and night sweats soaked his bed sheets. He was admitted to a hospital and diagnosed that September, his wife Bianca said.
Doctors have given Lomeli high doses of medication, one that turned his vision red, and he may have to take medication the rest of his life, Bianca said. Lomeli, who has five children, improved enough to return to his forklift driver job with a Modesto company, but it’s still a struggle.
“He feels tired, like he’s walking with bricks on his legs,” Bianca said.
Two years of elevated valley fever counts in Stanislaus County and other counties where it’s endemic followed weather patterns that are key to predicting outbreaks, according to experts who study the disease. The El Nino storms of late 2015 and early 2016 gave Modesto more than 17 inches of rain, or 5 inches above normal, and the storms last winter caused Sierra reservoirs to fill and spill water.
Pappagianis said those kind of winters in California create a moist environment for the coccidioides fungi to grow in soil types that host cocci. When the ground dries out months later, the soil is more laden with the fungal spores, which are carried in dust stirred by construction and other activities.
People breathing in the spores are infected, and cases sharply increase. Following winters with less rain, there is not as much fungus in the ground and fewer people get sick.
The danger of catching valley fever continues into the fall, until the next rain season suppresses the dust and fungus in the ground. This fall has been rather dry, with less than an inch of precipitation recorded in downtown Modesto. Valley fever experts like Pappagianis won’t sleep easier until the rain returns.
Milton David, a retired orthopedic surgeon in Modesto, recently expressed the opinion that almond harvest dust contributed to the upsurge in valley fever. The fall harvest is notorious for creating dusty air in a county with 182,000 acres of almonds in production. Over a lengthy career in Modesto, David treated patients with painful cocci lesions on their tendons and joints.
Dr. Robert Tanaka, a pulmonary disease specialist in Modesto for 35 years, joined the debate last week with his own assessment. Tanaka, a physician with Sutter Gould Medical Foundation, said he has not seen a correlation between the almond harvest and patients coming to him for treatment of cocci-related pneumonia .
Tanaka cited previous outbreaks of valley fever among construction workers, solar-farm workers near San Luis Obispo, workers laying pipelines and students taking part in archeological digs.
A research paper concluded that dust clouds created by the Northridge earthquake in 1994 was to blame for more than 200 cases of valley fever in Ventura County in the two months after the quake.
Tanaka said he hasn’t seen almond-harvest workers come down with valley fever. “The (patients) I have seen were usually working in construction,” said Tanaka, who’s given talks on valley fever at Modesto Junior College and continuing education seminars.
If the almond harvest was a factor in valley fever, “you would expect a lot of farmworkers who work in almonds to get this,” he said.
Pappagianis said people working in agriculture come down with valley fever, but a connection between the disease and agricultural land has not been well studied.
“We have had an impression that soil that’s cultivated regularly will not support the growth of fungus very well,” Pappagianis said. Microorganisms that support crops are more dominant in soil that’s cultivated, irrigated and fertilized.
Agricultural workers may be infected by dust coming off roads or that has settled on grape leaves and trees, Pappagianis said. “I would not ascribe it to any specific crop.”
Public health literature on valley fever usually warns about digging in undisturbed ground where cocci is present in the San Joaquin Valley, Central California and other western states.
Disease experts today still rely on the epidemiological studies of Charles Smith, a Stanford physician who first investigated valley fever among Dust Bowl migrants in the 1930s and military service people who trained at valley bases in World War II. Both populations came to California without immunity to the fungal disease.
Among other discoveries, Smith noted over time that the incidence of valley fever changed with weather patterns. The amount of winter rain seemed to determine how many cases would emerge in the summer and fall.
The same effect was reported after the 1987-to-1992 drought, Pappagianis said, when the dry years were followed by soaking rains in the valley and summertime outbreaks of cocci.
Arizona has two annual seasons of valley fever, arriving like clockwork months after winter rainfall and a July-August “monsoon” period, Pappagianis said.
In California, valley fever set what was then a record in 2011 with 5,213 cases statewide. Modesto’s rainfall totals of 16 inches and 16.76 inches in 2010 and 2011, respectively, well above the 12-inch average, gave way to three years with rain less than 10 inches. Valley fever dropped as low as 35 annual cases during the dry spell.
Stanislaus had 88 cases in 2016, growing to 118 in the first 11 months of this year.
Bianca Lomeli said she doesn’t believe the public health numbers draw such a clear picture of the prevalence of the disease. She suspects that people who are seriously ill are the ones counted.
Most people infected have no symptoms; others may have flulike symptoms that are not diagnosed. The complications of more severe disease include pneumonia and infection of the brain, joints, bone, skin and other organs. The disease can be fatal.
“People need to understand how serious the disease is,” said David Filip of Washington state, who’s the author of Valley Fever Epidemic and communications director for the Valley Fever Survivor group. “It can be reactivated in the body. People can be symptom-free for years and then have all kinds of symptoms.”
The California Department of Public Health has additional information on valley fever at www.cdph.gov.
Ken Carlson: 209-578-2321, @KenCarlson16