REVIEW
Coccidioidomycosis in African Americans

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Coccidioidomycosis is caused by Coccidioides species, a fungus endemic to the desert regions of the southwestern United States, and is of particular concern for African Americans. We performed a PubMed search of the English-language medical literature on coccidioidomycosis in African Americans and summarized the pertinent literature. Search terms were coccidioidomycosis, Coccidioides, race, ethnicity, African, black, and Negro. The proceedings of the national and international coccidioidomycosis symposia were searched. All relevant articles and their cited references were reviewed; those with epidemiological, immunologic, clinical, and therapeutic data pertaining to coccidioidomycosis in African Americans were included in the review. Numerous studies documented an increased predilection for severe coccidioidal infections, coccidioidomycosis-related hospitalizations, and extrapulmonary dissemination in persons of African descent; however, most of the published studies are variably problematic. The immunologic mechanism for this predilection is unclear. The clinical features and treatment recommendations are summarized. Medical practitioners need to be alert to the possibility of coccidioidomycosis in persons with recent travel to or residence in an area where the disease is endemic.

Section snippets

MYCOLOGY AND IMMUNOLOGY

Coccidioides is a dimorphic fungus that thrives in the soil of portions of the southwestern United States (Figure 1) and northern Mexico.3, 6 Two recognized species cause indistinguishable infection in humans: Coccidioides immitis and Coccidioides posadasii.1, 3 Coccidioides species grow as branching septate hyphae when the soil is moist. As the soil dries, thick-walled arthroconidia form6; when the soil and hyphae are disrupted, the disarticulated arthroconidia (spores) may become aerosolized.

INCIDENCE AND PREVALENCE

Recent population growth in the southwestern United States, where Coccidioides is endemic, has been rapid and racially diverse. For example, from 2000 to 2008, the population in Arizona increased 26% to more than 6.5 million persons.11, 12 During that same period, the number of African American residents in Arizona increased by 73%.12 The Southwest also serves as a winter vacation destination for an increasing number of travelers and part-time residents, who may return home after having

COCCIDIOIDOMYCOSIS IN PERSONS OF AFRICAN DESCENT

With the same level of exposure, persons of any particular race are not more likely or less likely to inhale airborne spores than persons of another race. Therefore, there is no known difference in the racial susceptibility to primary coccidioidomycosis.20 Of note, reported incidence data cite only identified cases, usually on the basis of symptoms, and do not reflect all primary coccidioidal infections, 60% of which are asymptomatic. Skin test reactivity to spherulin or coccidioidin more

LIMITATIONS OF LITERATURE

Most of the aforementioned studies are problematic to various degrees; their strengths and weaknesses have been summarized (eTable). Additionally, most of the studies are retrospective, which is a particular problem for studying coccidioidomycosis because asymptomatic or mild to moderate forms of the infection may be unrecognized, leaving only a minority of the more severe cases identified and treated by medical practitioners (and subsequently reported to public health officials). Many studies

MANAGEMENT

Treatment of coccidioidomycosis varies according to the clinical manifestations and anatomical sites of the infection. Specific antifungal drugs and treatment plans have recently been outlined in guidelines of the Infectious Diseases Society of America.54 The first step in management is to define the extent of a patient's disease.55

Optimal treatment of patients with self-limited pulmonary infection is an unsettled issue. Many experts do not recommend specific antifungal therapy in this

CONCLUSION

Coccidioidomycosis is a fungal infection endemic to the southwestern United States. Numerous retrospective studies have suggested that African Americans have an increased risk of severe or disseminated coccidioidal infections, but many of these studies are small and subject to potential bias. Prospective, controlled epidemiological studies are required to give a clearer picture of the true risk of complicated coccidioidomycosis among racial groups. Further study into the nature of inherent

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