Warning to Ventura County residents: The next time an earthquake hits, don’t breathe the dust.
Doctors who studied 1994’s deadly outbreak of valley fever in Ventura County conclude in a report that dust clouds kicked up by the Northridge earthquake carried fungus spores that caused the disease.
The report, appearing in today’s issue of the Journal of the American Medical Assn., is the first nationally published study tying an outbreak of the flu-like illness to an earthquake.
The report’s authors–including Ventura County health officials and researchers from the national Centers for Disease Control–said Tuesday that they hoped their research would warn people to steer clear of billowing dust during future quakes.
“Staying out of the dust clouds is about all we can do for prevention at this point,” said Gary Feldman, Ventura County health officer.
The report should also alert doctors to the possibility of valley fever cases after earthquakes, said author Eileen Schneider, a medical epidemiologist with the CDC.
“We want to make people aware so that if people come down with symptoms consistent with valley fever, there’ll be early diagnoses and treatment,” she said.
Researchers cautioned Tuesday that earthquakes trigger outbreaks of the disease only under specific circumstances. The fungal spore that causes the disease must be present in the soil and the earthquake must shake the ground violently enough to unleash the spores into the air.
The January 1994 Northridge earthquake apparently met those criteria. Between Jan. 24 and March 15 of that year, 203 cases of valley fever were reported in Ventura County, compared with less than 60 cases for all of 1993.
Most of the cases–56%–were in Simi Valley at the foot of the Santa Susana Mountains. The quake had unleashed landslides in the mountains and sent clouds of dust drifting over the city, while seaward winds blew some of the dust west into the Oxnard Plain.
Researchers found that many of the disease’s victims had been in a dust cloud unleashed by the quake. They found that people who reported being in a dust cloud were three times more likely to be diagnosed with valley fever than those who did not.
In addition, the risk of contracting the disease increased the longer people were in the dust cloud.
Symptoms of valley fever can vary. About 60% of those who become infected with the spores never know they are sick or suffer mild symptoms that they may dismiss as something else, Schneider said. Other people experience fatigue or respiratory problems similar to the flu.
About one in 200 cases will lead to more serious health problems, such as meningitis, Schneider said.
Three Ventura County residents died during the 1994 outbreak: a 71-year-old woman from Newbury Park, a 56-year-old Oxnard man and a 71-year-old Simi Valley man.
Schneider said that the disease can be treated with anti-fungal medications and that early detection helps treatment.