A Coccidioidomycosis Outbreak Following the Northridge, Calif, Earthquake

Abstract

Both the location and timing of cases strongly suggest that the coccidioidomycosis outbreak in Ventura County was caused when arthrospores were spread in dust clouds generated by the earthquake. This is the first report of a coccidioidomycosis outbreak following an earthquake. Public and physician awareness, especially in endemic areas following similar dust cloud-generating events, may result in prevention and early recognition of acute coccidioidomycosis.

Coccidioidomycosis: Host Response and Vaccine Development

“…Sievers (266), in his study of disseminated coccidioidomycosis in the American Indian population, found that children younger than 5 years and adults older than 50 years were significantly more susceptible than persons aged 6 through 49 years. An increased susceptibility of older persons was observed in the outbreak in Ventura County following the Northridge earthquake (260), in the 3-year coccidioidomycosis epidemic that started in San Joaquin Valley in 1991 (12,157) as well as a subsequent follow-up covering the period from January 1995 through December 1996 (248), and in analyses of cases of coccidioidomycosis in Arizona (182). In the last study, elderly persons who had recently relocated to Arizona appeared to be at the highest risk.…”

“…Coccidioidomycosis is considered to be a reemerging disease because of the dramatic increase in the number of cases during the early part of the past decade (47,52,105,157,207,219,260,282). Between 1991 and 1994, there was a notable increase of new cases in California, in particular in Kern and Tulare counties in the southern part of the San Joaquin Valley (219).…”

“…Since the early epidemiological studies by Smith et al (274,277,279), it has become almost axiomatic that fully 60% of primary infections with Coccidioides are asymptomatic, being evident only by conversion of skin test reactivity. Notable exceptions have occurred during outbreaks during archeological excavations, construction projects, and military exercises (83,180,260,282,302,307), where symptomatic infections have been documented in 90% or more of persons. This increased incidence of symptomatic infection following primary exposure to arthroconidia is probably attributable to exposure to an unusually high dose of arthroconidia (37).…”

“…This incidence has been higher in more recent studies. In an epidemiologic investigation of the outbreak that occurred in Ventura County following the earthquake in Northridge, Calif., in 1994, Schneider et al (260) reported that 3.7% of patients developed disseminated disease. Pappagianis and Einstein (221) (216).…”

Evaluation of Coccidioides exposures and coccidioidomycosis infections among prison employees.

“…Environmental conditions, including drought, precipitation, temperature, and wind speed, appear to have an impact on coccidioidomycois incidence [Comrie 2005]. Previous studies have hypothesized that Coccidioides spores (vegetative fungal cells in a resting state) are most abundant in the soil after heavy rains and may be most effectively dispersed during dry, hot periods, such as prolonged droughts [Smith et al 1946;Schneider et al 1997;Kolivras and Comrie 2003;Comrie 2005]. Thus, increased incidence of infection often occurs after a heavy wet season followed by a prolonged dry spell [Zender and Talamantes 2005].…”