Veterinary mycosis in a tropical country

Objectives:
The aim of this study is to present the experience of 10 years of work in veterinary mycology and research in mycotic diseases in companion, productive and wildlife animals in a tropical country.

Methods:
We analyzed databases, cases, and results of investigations in veterinary mycology generated in our laboratory from January 2008 to December 2017. A case of mycosis was confirmed if fungal structures were identified in clinical samples by direct microscopic examination, by the finding of fungal structures by histopathology and/or culture isolation. Results of lung cultures for avian aspergillosis controls in the poultry industry are presented. We also include the main findings of theses carried out in our laboratory.

Results:

For the study period of 2008-2017, there were a total of 2469 cases that underwent mycological analysis and 27.8% (686/2469) were confirmed with mycotic diseases. The most common mycosis was Malassezia spp. otitis and/or dermatitis with 36.1% (248/686), followed by dermatophytosis with 31% (213/686). Aspergillosis in poultry, in the third place, accounted for 26.7% (183/686) of the cases. Cryptococcosis, histoplasmosis, candidiasis, pythiosis, protothecosis, conidiobolomycosis, phaeohyphomycosis and hyphomycosis were demonstrated in wild and domestic’s animals in the remaining diagnoses mainly in the last five years.

Aspergillus section Fumigati was the most repetitive isolation in poultry lungs with 57.4% (105/183). Microsporum canis was the most common dermatophyte with 62.3% (96/154) in dogs and cats. Overgrowth of Malassezia spp. was observed in direct examinations and cultures from ear canal swabs of 100% (54/54) healthy pigs.

The frequency of canine dermatophytosis varied among different populations: our laboratory casuistry accounts of 11.3% (97/860), a regional survey 4.72% (6/127) and dogs from rural and indigenous areas without veterinary care 20% (25/127). Dermatophyte detection in the skin of cats from all over the country was of 17.1% (21/123) while this etiology was confirmed in 32.5% (88/271) of the samples sent to our laboratory.

Among the relevant findings from research performed in wild animals was the identification of Microsporum canis on the fur of 5% (4/79) asymptomatic free-living monkeys, and the isolation of Candida spp. from the ear canal in 23.1% (46/199) of apparently healthy bats. Injured Caribbean sea fans were demonstrated with dark septate and hyaline septate hyphae by histopathology and cultivation of the damaged tissues yielded fungal isolation in pure culture in 33.3% (3/9).

Conclusion:
Due to the climate conditions, Aspergillus sp. is an infectious agent widely prevalent and its control is important for the food industry. Superficial mycoses in dogs and cats are the most common fungal diseases identified in this tropical country with occurrence all over the year, nevertheless, variations in the frequency could be a result of the different geographic areas and living conditions of the animals. Confirmation of systemic and deep mycoses in wild and domestics animals have increased over the last years since veterinarians are more aware of the possibility of the mycotic etiology and are considering in their differential diagnosis. Mycological surveys in fauna contribute to baseline knowledge on fungal agents and further studies are needed in order to elucidate threats to wildlife conservation.

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