Coccidioïdomycose : une maladie d’importation d’actualité en France

Coccidioidomycosis: A Contemporary Review

Coccidioidomycosis, colloquially known as Valley Fever, is an invasive dimorphic fungal infection caused by Coccidioides immitis and C. posadasii. The fungi are found in the arid desert soils of the southwestern US, as well as in parts of Mexico and Central and South America. Acquisition is typically via inhalation of arthroconidia which become airborne after both natural (e.g., earthquakes, dust storms, and fires) and human-related events (e.g., military maneuvers, recreational activities, agriculture, and construction). The incidence of infection in increasing likely a result of both climatic and populational changes. Further, the recognized geographic distribution of Coccidioides spp. is expanding, as cases are being diagnosed in new areas (e.g., eastern Washington, Oregon, and Utah). Most coccidioidal infections are asymptomatic (60%); however, approximately one-third develop a pulmonary illness which is a leading cause of community-acquired pneumonia in highly endemic areas. Uncommonly (0.5–2% of cases), the infection disseminates to extrapulmonary locations (e.g., skin, bones/joints, and the central nervous system), and is most commonly seen among persons with cellular immunodeficiencies (e.g., transplant recipients, HIV, and pregnancy) and non-Caucasian races (especially African Americans and Filipinos). The diagnosis of coccidioidomycosis requires astute clinical suspicion and laboratory findings, including positive serology, cultures, and/or histopathology results. Treatment is warranted among persons with pneumonia who have risk factors for complicated disease and among those with extrapulmonary disease. Novel antifungals with improved fungicidal activity and rapidity of action with fewer side effects and drug interactions are needed. Preventive strategies (e.g., education regarding the disease, dust avoidance, mask wearing, including among select groups, antifungal prophylaxis, and surveillance laboratory testing) are advised for residents and travelers to endemic areas. Currently, no preventive vaccine is available. Coccidioidomycosis has been recognized for over a century, and an expanding wealth of knowledge has been gained regarding this emerging infectious disease which will be reviewed here.

Coccidioidomycosis: Epidemiology, Fungal Pathogenesis, and Therapeutic Development

Purpose of Review

Coccidioidomycosis can result from the inhalation of infectious spores of Coccidioides species (spp.) immitis or posadasii. Clinical manifestations range from mild flu-like disease to severe disseminated infection that can require life-long therapy. Burden of this mycosis is high in the southwest region of the USA where it is well characterized, and in many areas of Mexico and Latin America where it is inadequately characterized. Here, we provide historical data and current knowledge on Coccidioides spp. pathogenesis as well as recent progress in therapeutic and vaccine development against coccidioidomycosis.

Recent Findings

The virulence mechanisms of Coccidioides spp. are largely unknown; however, production and regulation of a spherule glycoprotein, ammonium production, and melanization have all been proposed as integral factors in Coccidioides spp.' pathogenesis. Therapeutic options are limited and not 100% effective, but individualized treatment with triazoles or amphotericin B over the course of pulmonary or disseminated infection can be effective in resolution of coccidioidomycosis. Human immunization has not been achieved but efforts are ongoing.

Summary

Advances in therapeutic and vaccine development are imperative for the prevention and treatment of coccidioidomycosis, especially for those individuals at risk either living or traveling to or from endemic areas.

Travel-related risk factors for coccidioidomycosis

BACKGROUND

Coccidioidomycosis is a regionally endemic systemic mycosis with unique risk factors. Since people travel for business or pleasure, and often in conjunction with their avocations or hobbies, the objectives of this review were to describe these and other risk factors for coccidioidomycosis; to alert travel medicine clinicians to the different presenting manifestations of coccidioidomycosis; and to recommend effective treatment, disease control and prevention strategies.

METHODS

To meet the objectives of this review, Internet search engines were queried with the keywords as medical subject headings over the study period, 1970-2017.

RESULTS

The principle transmission mechanism of coccidioidomycosis is by deep inhalation of aerosolized arthroconidia with resulting symptomatic pulmonary infections ranging from febrile influenza-like illnesses to fatal disseminated mycoses. In addition to residency or travel in endemic areas, persons immunocompromised by advancing age, pregnancy, cancer, corticosteroid therapy, diabetes, organ transplantation and human immunodeficiency virus infection are at significantly increased risks of contracting coccidioidomycosis. Persons of African, Asian, Filipino and Hispanic descent are also at increased risks of contracting coccidioidomycosis. Hobbies associated with coccidioidomycosis have included armadillo hunting, model airplane flying and archaeological digging. Occupational risk factors for coccidioidomycosis include endemic exposures during military maneuvers, outdoor track and field events, road construction, solar-power and wind-power farm construction, archaeological excavation and prison work.

CONCLUSIONS

Coccidioidomycosis is more common in endemic and non-endemic areas than previously recognized and can result in considerable morbidity and mortality. Coccidioidomycosis is increasingly imported from endemic areas in the Western Hemisphere to non-endemic areas worldwide. Increased awareness of disease risk factors among the public and the international healthcare community will improve the timely diagnosis and treatment of coccidioidomycosis and prevent disease progression, dissemination and deaths in residents in and in travellers returning from endemic regions. A vaccine for the primary prevention of coccidioidomycosis would be cost-effective.

Coccidioidomycosis: first imported case in Italy

We report a case of pulmonary coccidioidomycosis imported from the United States to Italy. This disease should enter in the differential diagnosis of any febrile patient (especially if presenting with pulmonary symptoms, with or without hypereosinophilia) coming from Coccidioides immitis endemic areas.

[Coccidioidomycosis presenting as a pulmonary nodule after pneumonia]

Coccidioidomycosis is a fungal infection endemic in the south west of the United States. Sixty percent of infected individuals remain asymptomatic. Symptomatic disease manifests itself with variable signs such as pneumonia, pleural effusion, empyema or acute respiratory distress syndrome. Residual disease includes pulmonary nodules and fibrosis. We report a case of a woman, returning from a trip to Arizona, presenting with an acute respiratory infection associated with erythema nodosum and arthralgia. She was successfully treated with routine antibiotics. The acute pneumonia resolved and the radiological infiltrate contract into a solitary pulmonary nodule. We suspected a malignant nodule in a previous smoker. The diagnosis of pulmonary Coccidioidomycosis was made after surgical resection. One year later, the patient is asymptomatic and well. This review focuses on the most common clinical manifestations, the diagnostic strategy and the treatment and management of pulmonary Coccidioidomycosis.

Coccidioidomycosis: an unexpected diagnosis in a patient with persistent cough

Coccidioidomycosis is an endemic fungal infection of the new world caused by Coccidioides immitis. Because of its low incidence in the European continent, the disease is not well known in Belgium. A 34-year-old male was referred by his general physician with a chronic cough and a nodular infiltrate on chest X-ray. Because a malignant tumour was suspected, a diagnostic work-up was performed and, finally, a broad excision of the pulmonary lesion was carried out. The unsuspected diagnosis of chronic coccidioidomycosis was eventually made based on identification of the filamentous fungus in mycological culture of the lung tissue, and the presence of the typical spherules with endospores upon histopathologic examination. The patient later admitted to have been travelling to Arizona frequently in the past year for professional reasons. Coccidioides spp. should always be considered as a possible aetiologic agent of pulmonary infection in former residents and recent travellers to regions where the fungus is endemic.