Pesquisa de dermatófitos em pets e no ambiente domiciliar

Resumo (EN)

Dermatophytes are important fungi for public health, being transmitted between animals and humans, causing zoonosis. These fungi have been reported in dogs, cats, guinea pigs, and rabbits, among other pets, being isolated from animals with or without lesions, representing infection sources for other animals and human beings. The aim of this research was to diagnose dermatophytosis in pets with lesions clinically consistent with this infection; investigate the presence of dermatophytes in their household environment; compare two diagnosis techniques: direct examination and culture; and two techniques to collect clinical samples, skin scraping/hair traction, and rubbing the haircoat with a carpet. Samples from haircoat were collected from 70 pets of both genders and varying ages. Of these samples, 47 (67.1%) were from dogs, 19 (27.1%) from cats, three (4.3%) from guinea pigs and one (1.4%) from a rabbit. There were visited 26 homes of animals that had the disease confirmed by mycological culture. There were collected 212 samples in the household environments, 24 samples from other animals that were in contact with the infected animals and 188 from selecting objects/sites with the help of owners. Many of these sites were of human-animal common use, but they were categorized as follows: 78 (41.5%) samples from sites that were of predominant use by the owners (sofas, chairs, beds, sheets); 66 (35.1%) samples from sites of predominant use by the animals (animals’ houses, cribs, toys, feeders); and 44 (23.4%) samples from general flooring (carpet, wood). To compare the collecting techniques, we collected 67 samples originating in pets, using both methods mentioned above. To compare the diagnostic techniques, direct examination and culture, 66 samples have been used. Samples from the animals and the environment were seeded on Mycosel agar (BBL-BD) and incubated at 25° C for up to four weeks. Colonies were submitted to microculture technique and identified by their macro-and-microscopic characteristics. For direct examination, skin scales/hair have been clarified with 20% potassium hydroxide (KOH), and optical microscope readings were taken at 100X and 400X. Statistical analysis to compare the employed techniques was performed using the McNemar test (p≤0.05). Dermatophytes were found in 37.1% (26/70) of the samples originated in sick animals. Microsporum canis was the most prevalent dermatophyte isolated in 20 animals (20/26-76.9%), 12 dogs and eight cats; Trichophyton quinckeanum was isolated in three guinea pigs (3/26-11.5%), Microsporum gypseum in two dogs (2/26- 7.7%) and Trichophyton mentagrophytes in a cat (1/26 - 3.8%). Dermatophytes were found in 69.2% (18/26) of the surveyed homes. Among the samples taken from household environments, 34.6% (65/188) were positive, with dermatophytes isolated in 29.5% (23/78) of the sites/objects of predominant use by owners, 42.4% (28/66) from sites/objects of prevalent animal use, 31.8% (14/44) from floors, and 50.0% (12/24) from animals that had some contact with infected animals. The same species of dermatophytes previously detected in animals with lesions were isolated in homes. Isolation of dermatophytes was obtained in 23/67 (34.3%) and 22/67 (32.8%) samples, collected respectively by hair traction and carpet friction, with no statistical differences between the two methods (p=1). Between the diagnostic techniques, 9/66 (13.6%) samples were positive on direct examination and 22/66 (33.3%) in culture, though the last method was statistically superior (p=0.03). Animals that showed no lesions, but from which dermatophytes had been isolated, were considered asymptomatic carriers, and they also represent sources of infection, helping to spread the fungus in the household environment. Nowadays the contact between humans and pets is becoming more intimate, with greater sharing of the same space in a home, making dermatophytosis important in medical/veterinary clinics and in public health as a whole