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New Zealand Veterinary Journal Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/tnzv20

Dermatophytes isolated from domestic and feral animals a

b

Miriam G. Carman , F.M. Rush-Munro & Margery E. Carter a

a

Ruakura Animal Health Laboratory , Private Bag, Hamilton, New Zealand

b

National Health Institute , Box 7126, Wellington, New Zealand Published online: 23 Feb 2011.

To cite this article: Miriam G. Carman , F.M. Rush-Munro & Margery E. Carter (1979) Dermatophytes isolated from domestic and feral animals, New Zealand Veterinary Journal, 27:7, 136-144, DOI: 10.1080/00480169.1979.34628 To link to this article: http://dx.doi.org/10.1080/00480169.1979.34628

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136

NEW ZEALAND VETERINARY JOURNAL

VOL 27

Dermatophytes isolated from domestic and feral animals Miriam G. Carman*, F. M.

Rush-Munro~"::,

and Margery E.

Carter~'

N.z. veU.27: 136 & /43-4

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ABSTRACT

In work over a period of8 years, dermatophytes were recovered from 12 animal species in the North Island of New Zealand. A total of 552 dermatophytes were isolated and belonged to the Microsporum (6 species) and Trichophyton (6 species) genera. Some unusual isolations are reported: Microsporum canis and Trichophyton mentagrophytes var. mentagrophytes were recovered from calves; Microsporum distortum from a dog, which was the first known isolation from an animal in the North Island; four horses, from the same stable, yielded Microsporum equinum which has not previously been recorded in this country; Trichophyton erinacei was recovered from lesions on a cat which is the first report of the dermatophyte from an animal other than the dog, hedgehog or man; Trichophyton equinum var. autotrophicum was a rare isolation from a dog. Species affinity was demonstrated with the dermatophytes M. canis; M. nanum; M. equinum; T. equinum; and T. verrucosum. These zoophilic species appear to be passed between individuals of the same species, with occasional infection in man and other animal species. T. mentagrophytes var. mentagrophytes had a wider distribution, being isolated from dogs, cats, guinea-pigs and rats. The infection in rats was subclinical. The geophilic species M. cookei, T. ajelfoi and T. terrestrewere recorded but not regarded as being pathogenic. M. gypseum was significant in cases involving dogs, horses and a cat, as arthrospores were seen invading the affected hairs. INTRODUCTION

Dermatophytes from a variety of animals are recorded that were isolated over a period of 8 years. The clinical features are discussed briefly when the isolations were uncommon, or when a dermatophyte was cultured from an unusual host. MATERIALS AND METHODS

Samples from domestic animals with lesions were supplied by veterinarians practising in the northern half of the North Island. The remainder of the specimens were obtained from feral animals in the North Island. Rats, obtained during a survey of the pathogens carried by them, were routinely examined for dermatophytes, but other feral animals were investigated because they had skin lesions. Clinical samples usually consisted of hair and scab plucked, or scraped. from lesions. The feral animals were sampled by brushing the hair coat with small squares of sterile carpet. Specimens from all animal species were inspected for ectoparasites in addition to dermatophytes. Scab specimens from horses and ruminants were examined also for Dermatophilus congolensis using a modified Gram stain. Isolation of dermatophytes was made on a Sabouraud dextrose agar with cycloheximide, minomycin and gentamicin added to a final concentration of 0.5 mg/ml, 0.1 mg/ml, and 0.1 mg/ml, respectively. The culture plates were incubated at 32°C for 3 weeks, except for specimens from cattle when duplicate plates were incubated at 32°C and 37°C for up to 6 weeks. *Ruakura Animal Health Laboratory. Private Bag, Hamilton. New Zealand. ·*National Health Institute, Box 7126, Wellington, New Zealand.

With the exception of8 specimens from cats and 15 from dogs which yielded Microsporum canis, all specimens from these animals were examined under the Wood's lamp (ultraviolet radiation). When sufficient material was available, all specimens, except those from rats, were examined by direct microscopy. The hair and scab material was softened in 20% KOH for 24 hours, and then examined for arthrospore formation. RESULTS

Culture A total of 2483 specimens from 17 animal species were examined for dermatophytes over an 8-year period. Table I indicates the Microsporum and Trichophyton species that were isolated from 2430 samples obtained from 12 hosts. No dermatophytes were cultured from the remaining S3 specimens; these were from goats (20 specimens) birds (9) hedgehogs (10) hares (13) and a llama. Wood's Lamp Only 31.6% of the specimens from dogs and cats that yielded M. canis fluoresced under the lamp. The hairs from the dog, from which Microsporum distortum was isolated, also fluoresced. In 19 (6.7%) cases, hair from dogs and cats fluoresced under the lamp but no dermatophytes were isolated. Microscopy Table II indicates the correlation between observation of arthrospores and eventual isolation of dermatophytes. Arthrospores were not seen in hair from which Microsporum cookei, Trichophyton ajelloi, or Trichophyton terrestre were isolated. Dermatophytes could not be isolated from seven hair samples (3.4%) in which arthrospores were observed. Other Findings D. congolensis was found in specimens from cattle (98 cases) horses (47) sheep (20) and goats (7). Two horses had a dual M. canis / D. congolensis infection, and a calfwas infected with both T. verrucosum and D. congo/ensis. Chrysosporum keratinophilum was isolated from three rats and Aphanoascus fulvescens from two rats. These fungi closely resemble the geophilic dermatophytes, and probably represent contamination from soil. Mycologically, their differentiation from dermatophytes is important. Various genera of mites were seen in direct microscopy, and a diagnosis of mange. unassociated with dermatophytes, was made in dogs (12 cases) pigs (6) cats (5) cattle (5) and hedgehogs (3). DISCUSSION

. Microsporum canis was isolated most commonly from cats and dogs. Four cases occurred in horses and one isolation was made from a three-month-old Ayrshire heifer. The heifer had alopecia and scabs along its back, resembling streptothricosis, but D. congolensis was not detected. M. canis was cultured as a pure heavy growth and arthrospores were observed in some of the affect~d hairs. Hair samples were obtained from two cats and two dogs on the same property but M canis was not isolated from them. (Continued on page 143)

1979

NEW ZEALAND VETERINARY JOURNAL

143

(Continued/rom page 136)

The geophilic. keratinophilic dermatophytes M. cookei, T. ajel/oi and T. t?rrestre are common soil inhabitants. No arthrospores were seen in hairs from cases in which these three dermatophytes werc cultured, so the isolates probably represent contamination of the hair by soil, and their presence was unlikely to have been related to the skin lesions. M. gypseum is also a geophilic dermatophyte and, because of this, isolation of this fungus does not necessarily establish a diagnosis of ringworm. However, arthrospores were seen in the hairs when M. gypseum was isolated from dogs (7 cases) horses (8) and a cat. Therefore, it was thought that M. gypseum was responsible for the lesions in these cases. M. distortum appears to have a limited distribution here, and

Only 31.6% of specimens from dogs and cats that proved to be mycologically positive for M. canis fluoresced under the Wood's Lamp. This percentage is in agreement with information from the USA (30%)1'> and UK (44%)18>. It was thought that the fluorescence seen in 19 samples of hair from cats and dogs, when no dermatophytes were seen or cultured, may have been due to skin medication. Arthrospores were observed in 46% of hair samples that yielded M. canis. This low proportion might be due to several factors: the samples sent to the laboratory are often meagre; sometimes the hairs are cut and not plucked from the animal; and. in dogs especially, there is the difficulty of seeing arthrospores if the hairs are black.

TABLE I: DERMATOPHYTES ISOLATED FROM DOMESTIC & FERAL ANIMALS OVER AN 8-YEAR PERIOD (1971-8) on

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