Coccidioidomycosis Outbreak
Coccidioidomycosis Outbreak
Abstract & Commentary
Synopsis: Eighteen of 19 physicians failed to diagnose coccidioidomycosis in members of a church group from Washington returning from Mexico.
Source: Cairns L, et al. Outbreak of coccidioidomycosis in Washington State residents returning from Mexico. Clin Infect Dis 2000;30:61-64.
A cluster of flulike illnesses in a church group was reported to the Washington State Department of Health in July 1996. The 126-member group had recently returned from Tecate, Mexico, a town in the Sonoran Desert adjacent to the United States-Mexico border, where members had stayed in an orphanage for six days and assisted in construction projects. One person was eventually diagnosed with coccidioidomycosis. As a result, a retrospective cohort study was conducted to assess the extent of the outbreak and risk factors for acquisition of this disease.
Investigators used a questionnaire to collect demographic data, travel and medical histories, information on activities while in Tecate, and symptoms of illness since the trip. Spherulin skin tests were done on all consenting group members. Serum specimens were collected from persons with any flulike symptoms or those with a positive skin test. These specimens were tested for antibodies to Coccidioides immitis by 1) quantitative complement fixation (CF) tests; 2) immunodiffusion tube precipitin (IDTP) for IgM antibody; and 3) immunodiffusion complement fixation (IDCF) for IgG antibody. A case of acute coccidioidomycosis was defined by a positive serological test for C. immitis. In addition, soil specimens were collected from various sites at the orphanage in Tecate and inoculated into mice for growth of C. immitis.
Of the 126 members, 59 (47%) completed questionnaires and underwent skin tests. Thirty-five (59%) were female and 51 (86%) were 14-18 years of age. None reported being immunocompromised or pregnant. Twenty-seven (46%) members had a positive skin test. Forty members underwent serological testing. Twenty-one of these members met the case definition of coccidioidomycosis with positive serology. The majority of cases were adolescents (95%) and female (86%). The attack rate for the 59 members who responded to the questionnaire was 36%, and the minimum attack rate for the entire group was 17%. A total of 95% of the cases were symptomatic, with an average incubation period of 12 days (range, 7-20 days). The symptoms included fever (85%), headache (81%), chest pain (76%), body aches (71%), cough (66%), fatigue (66%), rash (62%), muscle pain (52%), nausea (43%), and joint pain (33%). Four patients reported lesions consistent with erythema nodosum.
A total of 16 symptomatic patients saw 19 health care providers, who appeared to be aware of the patients’ travel history. The patients were diagnosed with bacterial bronchitis, contact dermatitis, and viral infection. Only an infectious disease specialist trained in California made the diagnosis of coccidioidomycosis after seeing a patient with erythema nodosum.
Analysis of reported activities found that digging a swimming pool was associated with an increased risk of acute coccidioidomycosis. Furthermore, soil inoculation studies yielded illness in mice as well as lesions that contained spherules characteristic of C. immitis.
Comment by Lin H. Chen, MD
Coccidioidomycosis is caused by C. immitis, a dimorphic fungus. The mycelial form is found in soil, which produces arthroconidia that become airborne. When inhaled by a host, the arthroconidia develop into spherules and cause infection.1,2
C. immitis is endemic in the southwestern United States—primarily California, Arizona, Texas, and New Mexico.3 C. immitis is also highly endemic in parts of Mexico, including Sonora, Chihuahua, Coahuila, Sinaloa, Nayarit, Jalisco, Colima, Coshuila, Nuevo Leon, Durango, San Luis Potosi, and Guanajuato. Venezuela has endemic areas in the northwestern states of Falcon, Lara, and Zulia. Other endemic areas include Comayagua Valley in Honduras, the Motagua River Valley in Guatemala, and Patagonia and Rio Hondo in Argentina. Cases have also been reported in Bolivia, Paraguay, and Colombia.4
Sixty percent of those infected with C. immitis are asymptomatic or have symptoms resembling an upper respiratory infection.1,5 They are only diagnosed because of positive coccidioidal skin tests. The other 40% develop a pulmonary infection after an incubation period of 1-3 weeks. The clinical presentation may include cough, sputum production, fever, chills, anorexia, weakness, arthralgias, chest pain, and rashes such as erythema nodosum or erythema multiforme. Chest radiography may show infiltrates, pleural effusions, and hilar adenopathy. The acute infection usually resolves without specific treatment, although the symptoms may last several weeks. Five percent of those infected may have remaining pulmonary nodule or cavitary lesions, and a progressive pneumonia or chronic lung infection can occasionally develop. Disseminated infections may develop in 0.5-1% of infected people, more commonly in immunocompromised hosts, pregnant women, diabetics, and nonwhites.3,7 The usual sites involved in disseminated infections are bone and joints, meninges, skin, and soft tissues.
A diagnosis of coccidioidomycosis can be made by culture, staining of tissue specimen, skin testing to coccidioidal antigens, and serology. The latter include the tube precipitin test for IgM, immunodiffusion test (for IgM and IgG), enzyme immunoassay (for IgM and IgG), and complement fixation test for IgG. Although most acute infections resolve spontaneously, progressive primary disease or disseminated disease requires treatment with amphotericin B and/or itraconazole or fluconazole.8
The study by Cairns and associates made some interesting observations. First of all, the majority (85%) of patients reported a rash, which was more frequent when compared to the incidence of rash (20%) in other reports.6 Cairns et al suggested that children and young adults possibly have a different clinical presentation during acute coccidioidomycosis. Second, the incidence of headache was also high (81%), yet the headaches did not appear to indicate meningitis. Next, excavation was a definite risk factor, similar to the outbreaks associated with archaeological digging.8 Finally, the study demonstrated the difficulty in recognizing and diagnosing coccidioidomycosis in nonendemic areas, emphasizing the need to improve health care providers’ awareness of the epidemiology and presentations of coccidioidomycosis. C. immitis is clearly endemic in areas of Central and South America as well as the southwestern United States. Physicians and travelers to these areas should understand the specific epidemiology, risk groups, and manifestations of coccidioidomycosis. Immunocompromised individuals should especially be aware of this disease. (Dr. Chen is Clinical Instructor, Harvard Medical School and Travel/Tropical Medicine Clinic, Lahey Clinic Medical Center.)
References
1. Deresinski SC, Kemper CA. Coccidioides immitis. In: Gorbach S, Bartlett J, Blacklow N, eds. Infectious Diseases. Philadelphia, Pa: W.B. Saunders; 1998:2344-2360.
2. Deresinski SC, Kemper CA. Coccidioidomycosis. In: Schlossberg D, ed. Current Therapy of Infectious Disease. 2nd ed. Philadelphia, Pa: Mosby Year Book; 2000: in press.
3. Einstein HE, Johnson RH. Coccidioidomycosis: New aspects of epidemiology and therapy. Clin Infect Dis 1993;16:349-354.
4. Kirkland TN, Fierer J. Coccidioidomycosis: A reemerging infectious disease. Emerg Infect Dis 1996;2(3):192-199.
5. Rios-Fabra A, et al. Fungal infection in Latin American countries. Infect Dis Clin North Am 1994;8(1):129-154.
6. Smith CE, et al. Varieties of coccidioidal infection in relation to the epidemiology and control of the disease. Am J Public Health 1946;36:1394.
7. Stevens DA. Coccidioidomycosis. N Engl J Med 1995; 332(16):1077-1082.
8. Werner SB, et al. An epidemic of coccidioidomycosis among archeology students in northern California. N Engl J Med 1972;286:507-512.
Which of the following are true regarding coccidioidomycosis?
a. Culture, serology, skin test, or tissue staining can diagnose coccidioidomycosis.
b. C. immitis is endemic in the southwestern United States as well as northwestern Mexico, Venezuela, parts of Honduras, Guatemala, Argentina, Bolivia, Paraguay, and Colombia.
c. The majority of acute infections with C. immitis are asymptomatic or mild upper respiratory infections.
d. Clinical presentations of coccidioidomycosis include cough, fever, chills, arthralgias, erythema nodosum, and weakness.
e. All of the above
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