An outbreak of acute pulmonary histoplasmosis in members of a trekking trip in Martinique, French West Indies

Abstract

Background: Thirteen clustered cases of American histoplasmosis, a deep mycosis caused by Histoplasma capsulatum and acquired through inhalation of airborne spores was reported. Twenty-five persons traveled in Martinique, French West Indies. Thirteen underwent trekking and passed through a mountain tunnel full of bats (tunnel group). The 12 others performed canyoning and did not go through the tunnel (control group). Fifteen days after exposure, 1 patient of the tunnel group developed fever, chills, and cough. Methods: The index case was diagnosed in the hospital, but 12 cases where initially diagnosed as prolonged influenza. All individuals were contacted and submitted to a phone questionnaire. They were asked about eventual occurrence of influenzalike symptoms, about activities practiced, and the notion of contact with bats. All were invited to have clinical examinations, chest x-ray films, and blood samplings. Serologic testing for histoplasmosis was performed by immunodiffusion. Clinical evidence of infection with H. capsulatum was obtained in all the remaining patients of the tunnel group and in none in the control group. Symptoms occurred with an acute onset in 11 to 23 days: fever and chills, severe asthenia, headaches, digestive tract involvement, and then cough, dyspnea, hepatic involvement. Pulmonary micro- or macronodules and mediastinal adenopathies were seen on radiograph and/or computed tomography scan. Results: H. capsulatum serologic tests were positive in all 13 cases with presence of specific M and or H precipitins, 5 to 13 weeks after exposure, and were negative in control group. All patients were treated with itraconazole 200 mg per day during at least 2 months. Treatment was well tolerated; patients progressively recovered. Clinical and serologic follow-up was obtained for some patients at 1 and 4 years. The present study reports the first large outbreak of histoplasmosis acquired in Martinique. Conclusion: Histoplasmosis still occurs and is potentially serious. In patients returning from endemic areas, presenting prolonged influenzalike symptoms, clinicians should look for previous possible exposure to Histoplasma.