Coccidioides posadasii Infection in Bats, Brazil

Rossana de Aguiar Cordeiro

, Kylvia Rocha de Castro e Silva, Raimunda Sâmia Nogueira Brilhante, Francisco Bergson Pinheiro Moura, Naylê Francelino Holanda Duarte, Francisca Jakelyne de Farias Marques, Rebecca de Aguiar Cordeiro

, Renato Evando Moreira Filho, Roberto Wagner Bezerra de Araújo, Tereza de Jesus Pinheiro Gomes Bandeira, Marcos Fábio Gadelha Rocha, and José Júlio Costa Sidrim

Author affiliations: Universidade Federal do Ceará, Fortaleza-Ceará, Brazil (R.A. Cordeiro, K.R.C. Silva, R.S.N. Brilhante, F.J.F. Marques, R.A. Cordeiro, R.E. Moreira Filho, R.W.B. Araújo, T.J.P.G. Bandeira, M.F.G. Rocha, J.J.C. Sidrim); Instituto Federal de Educação, Ciência e Tecnologia, Ceará, Brazil (K.R.C. Silva); Universidade Estadual do Ceará, Fortaleza- Ceará (M.F.G. Rocha); Secretaria da Saúde do Estado do Ceará, Ceará (F.B.P. Moura, N.F.H. Duarte)

Abstract

To analyze the eco-epidemiologic aspects of Histoplasma capsulatum in Brazil, we tested 83 bats for this fungus. Although H. capsulatum was not isolated, Coccidioides posadasii was recovered from Carollia perspicillata bat lungs. Immunologic studies detected coccidioidal antibodies and antigens in Glossophaga soricina and Desmodus rotundus bats.

Studies have demonstrated that bats (order Chiroptera) are reservoirs for many infectious agents, including protozoa, bacteria, viruses, and fungi (1). Several studies confirm that bats have a great effect on human health because they can transmit numerous infectious agents and provide a reservoir for emerging pathogens (1,2). The interaction between these animals and pathogenic fungi is well illustrated by the occurrence of histoplasmosis outbreaks in humans who are exposed to bat droppings in the environment (3,4). In Brazil, histoplasmosis is an endemic disease that occurs mainly in patients with AIDS (5), but Histoplasma capsulatum var. capsulatum has also been isolated from bats captured in urban areas (4).
To analyze the eco-epidemiologic aspects of H. capsulatum in northeast Brazil, we captured bats from urban and rural areas of Ceará State. However, the research revealed the existence of a bat that was naturally infected with Coccidioides posadasii and 2 other chiropterans with coccidioidal immunologic responses. This fungal pathogen can cause coccidioidomycosis, a serious infection in humans and animals. The mycosis is presently considered to be endemic to Northeast Brazil, as evidenced by human autochthonous cases (6–8), positive coccidioidin skin-test results (7), and isolation of the fungus from soil (7,9). We describe the isolation of C. posadasii in bats and discuss the epidemiologic effects of this finding.

The Study

From August 2010 to March 2011, a total of 83 bats of 7 species were captured in 6 cities in Ceará State, Northeast Brazil, where patients with histoplasmosis are seen: Ubajara, Itapiúna, Quixadá, Russas, Aracoiaba, and Baturité. The animals were captured during the day (nonhematophagous bats) or night (hematophagous bats) by using nylon mist nets with 36-mm mesh. The study was part of the rabies control surveillance program headed by the Ceará State Health Department and was approved by the ethics committee of the State University of Ceará (process 07381395–8).
Immediately after capture, the bats were euthanized by an overdose of diethyl ether by inhalation, and their spleen, liver, and lungs were analyzed for H. capsulatum isolation. Fragments of each organ were homogenized by maceration in saline supplemented with 200 mg/L chloramphenicol. Aliquots of 100 µL were seeded onto plates containing brain–heart infusion agar, supplemented with 1% glucose, 0.1% l-cysteine, 200 mg/L chloramphenicol, and 0.05% cycloheximide, and incubated at 25°C or 35°C for as long as 6 weeks (10). Remaining aliquots of each homogenate, as well as organ fragments, were kept at −20°C.