An old disease — in new immigrants

By Carol A. Kemper, MD, FACP

Clinical Associate Professor of Medicine, Stanford University, Division of Infectious Diseases, Santa Clara Valley Medical Center

Dr. Kemper does research for Abbott Laboratories and Merck; this article originally appeared in the June issue of Infectious Disease Alert.

Coccidioidal infections are always unique — the travel history often provides the right clue for the practitioner — but first you have to think to ask the right question. My practice has recently seen three Asian immigrants hospitalized with what proved to be acute coccidioidomycosis; two of whom had focal pulmonary disease (one with cavities and erythema nodosum) and the third with evidence of dissemination to mediastinal nodes and skin. All three were suspected of having pulmonary tuberculosis until pathology and fungal cultures surprisingly revealed coccidioidomycosis. The first two patients were Asian Indian and the third was Chinese. All three worked in high tech in Silicon Valley, were young (28-40 years of age), were in good health, and had recent, albeit brief, exposure to an endemic area. Two of the patients had traveled down Highway 5 from the Bay Area to Las Vegas for holiday, stopping for gas and food along the way. The third, who was Chinese, had traveled to Phoenix for business for 3 days, and had lunch on the outskirts of the city at an outdoor Mexican restaurant.

These cases are reflective of some of the people acquiring coccidioidal infection around the United States — young, healthy Asian or Latin American immigrants who happen to be exposed while vacationing or working in higher risk areas of California and Arizona. None of my patients had ever heard of cocci before.

Increases in coccidioidomycosis are occurring in both California and Arizona (approximately 60% of cases in the United States are reported from Arizona).1 From 2000 to 2006, California cases increased from 816 to 2,981. The estimated average annual incidence in California is highest among 40- to 49-year-olds, while hospitalizations are highest among persons aged 60-79 (5.8 hospitalizations per 100,000). Two-thirds of cases (65%) were reported in males. Hospitalizations were highest among non-Hispanic blacks (7.5 per 100,000), followed by Hispanics (3.6 per 100,000), non-Hispanic whites (3.5 per 100,000), and Asians/Pacific Islanders (1.9 per 100,000). From 2000 to 2007, 752 (8.7%) of those 8,657 persons in California requiring hospitalization died. About three-fourths of California cases are acquired in the San Joaquin Valley area, where C. immitis is endemic, with the hot spot being Kern County.

The reason for this apparent increase is not well understood. Mandatory reporting requirements for coccidioidomycosis in California have not changed. Climatic changes and increases in rainfall may impact disease incidence (so this coming year should see an increase in cases in California with the bonanza of winter rain). Increasing numbers of non-immune immigrants from Latin America or Asia and elderly persons who travel for business or pleasure may provide an explanation. My theory is that the booming housing industry in the 2000s and expansion of urban residential areas in both Arizona and California probably played a significant role. Interestingly, based on preliminary data for 2008-2009, cases in Arizona and California may have modestly decreased in 2008. Perhaps the downturn in the housing economy and negative impact on new construction in endemic areas, as well as a decrease in business and vacation travel, had a positive effect on total numbers of coccidioidal infections.

Reference

  1. Centers for Disease Control and Prevention. Increase in coccidioidomycosis — California, 2000-2007. MMWR Morb Mortal Wkly Rep 2009;58:105-109.