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Coccidioidomycosis -- United States, 1991-1992
During 1991, reported cases of coccidioidomycosis (i.e., valley fever) in California increased more than three-fold over the annual number of cases reported since 1986; during 1992, the number of reported cases increased 10-fold. Coccidioidomycosis, a fungal disease caused by Coccidioides immitis, is endemic in certain parts of Arizona, California, Nevada, New Mexico, Texas, and Utah. Sporadic cases occur each year in parts of the United States in which the disease is not endemic and may present diagnostic difficulties and laboratory hazards because health-care workers may be unfamiliar with coccidioidomycosis. Recent increases in California and reports of isolated cases in areas without endemic disease suggest that physicians and laboratory personnel should be alert to the possible role of C. immitis. This report summarizes the occurrence of coccidioidomycosis in California during 1991 and 1992 and highlights three cases that occurred in areas in which the disease is not endemic. Outbreak in California
In 1991, 1208 new cases of coccidioidomycosis were reported to the California Department of Health Services (CDHS), compared with an average of 450 cases per year during the previous 5 years. Of these cases, 959 (80%) were reported from Kern County, where coccidioidomycosis is known to be endemic and where the county health department serves as a referral laboratory for coccidioidomycosis serologic tests. Of all cases reported to CDHS in 1991, 765 (63%) were reported from October through December. In 1992, 4541 cases of coccidioidomycosis were reported to CDHS (Figure 1). Of these, 4198 (92%) were reported from the central valley and southern California, including 3027 (67%) from Kern County. Reports from the Coccidioidomycosis Serology Laboratory of the University of California at Davis, a reference laboratory that receives specimens from areas of California other than Kern County, also documented an increased incidence in 1991 and 1992. Nonendemic Coccidioidomycosis
Although no national surveillance system exists for coccidioidomycosis, each year several cases are reported to CDC that occur outside of the southwestern United States, where the disease is endemic. Three such case- reports follow.
Case 1. In September 1992, a 24-year-old black man from Virginia developed pulmonary coccidioidomycosis 2 weeks after driving through California. He was admitted to a hospital after a chest radiograph indicated bilateral lower lobe infiltrates with extensive mediastinal and hilar lymphadenopathy. He was presumed to have bacterial pneumonia and was treated with antibiotics. Efforts to diagnose the pneumonia, which included bronchoalveolar lavage and transbronchial biopsy, were unsuccessful until an open-lung biopsy was performed. Culture of the biopsy specimen grew C. immitis. The patient was treated with an intravenous antifungal agent and was discharged after 12 days.
Case 2. In August 1992, a 13-year-old black male from Georgia developed symptoms that included hoarseness, noisy breathing, and difficult breathing 2 months after visiting southern California, Nevada, and northern Mexico. During initial evaluation, a laryngeal mass was detected; a laryngeal papilloma was suspected. Treatment with steroids and bronchodilaters resulted in symptomatic improvement. In October 1992, a subsequent laryngoscopy detected diffuse granular tissue on the larynx. Histopathologic examination of the biopsy revealed spherules of C. immitis and culture of the biopsy specimen grew C. immitis. The patient was treated with an intravenous antifungal agent and, after 5 days, was discharged on an oral antifungal agent.
Case 3. In October 1992, a 30-year-old black woman, who had previously resided in Arizona, was hospitalized in Florida because of chronic disseminated coccidioidomycosis. A slant of C. immitis culture isolated from her blood was inadvertently broken in the hospital's microbiology laboratory. The fungus had not been handled in a biological cabinet. The spill was promptly cleaned and disinfected. No subsequent evidence of clinical infection was found in potentially exposed laboratory personnel.
Reported by: D Pappagianis, MD, Univ of California, Davis; RK Sun, MD, SB Werner, MD, Disease Investigation Section, GW Rutherford, III, MD, State Epidemiologist, California Dept of Health Svcs. RW Elsea, MD, Lynchburg Family Practice, Univ of Virginia; GB Miller, Jr, MD, State Epidemiologist, Virginia Dept of Health. N Bootwala, MD, Egleston Children's Hospital, Emory Univ, Atlanta. RS Hopkins, MD, State Epidemiologist, Florida Dept of Health and Rehabilitative Svcs. Div of Field Epidemiology, Epidemiology Program Office; Div of Bacterial and Mycotic Diseases, National Center for Infectious Diseases, CDC.
Editorial Note: C. immitis resides in the soil in certain parts of the southwestern United States, northern Mexico, and a few other areas in the Western Hemisphere. Infection is caused by inhalation of airborne, infective arthroconidia, one stage in the organism's life cycle. In the host, these conidia convert into endosporulating spherules, the organism's other morphologic form. The disease is not transmitted from person to person (1-3).
A substantial proportion of adults who are long-time residents of areas where the disease is endemic have evidence of prior infection with C. immitis by positive coccidioidin or spherulin skin tests. However, in addition to sporadic disease, these areas also experience outbreaks, demonstrated by the recent sharp increase in disease incidence in California. The current outbreak in California may be associated with weather conditions, especially a recent protracted drought followed by occasional heavy rains. The magnitude of the outbreak may be partially explained by recent migration of persons previously unexposed to C. immitis into areas of California where coccidioidomycosis is endemic. This outbreak illustrates how factors such as weather and demographic changes can affect the emergence of public health problems from infectious diseases (4).
Approximately 60% of persons infected with C. immitis remain asymptomatic. Symptomatic coccidioidomycosis has a wide clinical spectrum, ranging from mild influenza-like illness to serious pneumonia to widespread dissemination. Dissemination outside the lungs occurs in approximately 0.5% of infections. Coccidioidal meningitis is a particularly serious manifestation of disseminated coccidioidomycosis. Among persons who become infected, blacks, Filipinos and other Asians, Hispanics, and women who acquire the primary infection during the later stages of pregnancy are at increased risk for disseminated coccidioidomycosis (2,3,5). Extrapulmonary coccidioidomycosis is an acquired immunodeficiency syndrome-defining illness when it occurs in a person with evidence of infection with human immunodeficiency virus (6).
Infection with C. immitis in persons residing outside coccidioidomycosis-endemic areas may occur as a result of travel in these areas, laboratory exposure, or inhalation of contaminated fomites (e.g., soil, cotton, packing material, or museum artifacts) taken from areas with endemic coccidioidomycosis (7,8).
In laboratory cultures, C. immitis develops the highly infectious mycelial form and may pose a hazard to laboratory workers if arthroconidia from cultures are inadvertently aerosolized. When clinical laboratories handle C. immitis, laboratory activities should be performed at biosafety level 3. Subculturing or harvesting of arthroconidia and opening tubes containing cultures of C. immitis should be performed only in an appropriate biological cabinet (9). Agar slants or bottles should be used, instead of petri dishes, for the isolation of C. immitis (10). If a plate culture is prepared, the plate should be sealed with adhesive tape once growth is evident, and the culture plate should be destroyed after 10-14 days. Cultures sent through the mail should be packaged and labeled in accordance with regulations concerning the interstate shipment of etiologic agents. *
Clinicians should consider the diagnosis of coccidioidomycosis in persons with undiagnosed respiratory illnesses or syndromes that could represent disseminated coccidioidomycosis for those who reside in, or have traveled to, areas where the disease is endemic, or who have had occupational exposure to C. immitis. Laboratory personnel should be reminded of necessary safety precautions when handling C. immitis.
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