Isolation of Dermatophytes from the Haircoats of Stray Cats from Selected Animal Shelters in two Different Geographic Regions in the United States

Résumé— Le but de cette étude était de déterminer la prévalence des isolements de Microsporum canisà partir de chats apparemment sains dans des refuges de deux régions de climats différents aux Etats-Unis. Deux cents chats (chats sans signes apparent de maladie) provenant d'une région froide et séche et d'une région chaude et humide ont étéétudiés et la technique de la brosse à dents utilisée pour la mise en culture et la rechehe de Dermatophytes. Cinq espèces de Dermatophytes communément associées aux dermatophyties humaines et animales ont été isolées: M. canis (n= 8), Trichophyton verrucosum (n= 5), T. mentagrophytes (n - 1), T. rubrum (n= 16), et Epidermophyton spp. (n= 5). Microsporum canis n'a été isolé que chez les chats vivant dans le Sud et principalement sur des chatons. Trichophyton rubrum a surtout été isolé chez les chats du nord. La prévalence de M. canis chez les chats sains était dans cet étude de 4 pourcent et la prévalence totale de tous les pathogénes de 17,5 pour cent. [Isolation of dermatophytes from the haircoats of stray cats from selected animal shelters in two different geographic regions of the United States. (Isolement de dermatophytes du pelage de chats errants pris dans des refuges de deux regions différentes des Etats-Unis.) Zusammenfassung— Ziel der Studie war, die Prävalenz von Microsporum canis-Isolaten von scheinbar gesunden Katzen in Tierheimen in zwei klimatisch unterschiedlichen Regionen der Vereinigten Staaten festzustellen. Zwei hundert Katzen (Katzen ohne makroskopische oder offenscichtliche physische Anzeichen von Krankheit) aus Tierheimen in einer relativ kalt-trockenen geographischen Region und einer feucht-war-men Region der Vereinigten Staaten wurden untersucht und aus dem Haarkleid mittels Zahnbürstentechnik Pilzkulturen angelegt. Es wurden fünf Arten von Dermatophyten identifiziert, die häufig mit menschlichen oder tierischen Hautpilzerkrankungen verbunden sind: M. cams (n= 8), Trichophyton verruscosum (n= 5), T. mentagrophytes (n= 1), T. rubrum (n= 16) und Epidermophyton spp. (n= 5). Microsporum canis wurde nur von Katzen aus dem Süden isoliert, vorwiegend von Katzenwelpen. Trichophyton rubrum wurde häufiger von Katzen aus dem Norden isoliert. Die Prävalenz von M. canis bei scheinbar gesunden Katzen in dieser Studie betrug 4 Prozent, die Gesamtprävalenz aller pathogenen Keime betrug 17,5 Prozent. [Isolation of dermatophytes from the haircoats of stray cats from selected animals shelters in two different geographic regions in the United States (Isolierung von Dermatophyten aus dem Fell von streunenden Katzen aus ausgewahlten Tierheimen in awei verschiedenen geographischen Regionen der Vereinigten Staaten.) Abstract— The purpose of this study was to determine the prevalence of Microsporum canis isolation from apparently healthy cats in shelters in two different climatic regions of the United States. Two hundred cats (cats without gross or obvious physical illness) from animal shelters in a relatively cold dry geographic region and a warm humid region of the United States were examined and their haircoat cultured for fungi using the toothbrush technique. Five species of dermatophytes commonly associated with either animal or human dermatophytosis were identified: M. canis (n= 8), Trichophyton verruscosum (n= 5), T. mentagrophytes (n= 1), T. rubrum (n= 16), and Epidermophyton spp. (n = 5). M. canis was isolated only from cats in the south, predominantly from kittens. T. rubrum was isolated more commonly from cats from the north. The prevalence of M. canis in apparently healthy cats in this study was 4 per cent and the overall prevalence of all pathogens was 17.5 per cent.     

Dermatophytes from skin lesions of domestic animals in Nsukka,Enugu State,Nigeria

Background – Dermatophytes are well‐recognized cutaneous fungi with public health implications. In Nigeria, several studies have been carried out on dermatophytosis in humans; however, data on dermatophytes in animals are lacking. Objectives – This study was conducted to determine the occurrence and species of dermatophytes in skin lesions in domestic animals in Nsukka Agricultural Zone of Enugu State, Nigeria. Animals – Forty‐six domestic animals (dogs, goats, sheep and pigs) presented for sale in the local markets in the study area and with suspected lesions of dermatophytosis were used for the study. Methods – Plucked hairs and epidermal scales from the skin lesions of affected animals were inoculated on Sabouraud dextrose agar slants containing 0.05 mg/mL of chloramphenicol and 0.5 mg/mL of cycloheximide. Inoculated slants were incubated at room temperature (27°C) for up to 4 weeks and examined at 2–3 day intervals for fungal growth. Laboratory identification of the fungal isolates was based on their colonial, microscopic and biochemical characteristics. Results – Of the 46 animals with suspected lesions of dermatophytosis, six (13.0%) were positive for a dermatophyte, and the following dermatophytes were identified: Microsporum gypseum, two of 12 sheep; Microsporum audouinii, one of 16 dogs; Trichophyton mentagrophytes, one of 16 dogs and one of 12 sheep; and Trichophyton schoenleinii, one of 13 goats. Conclusions and clinical importance – Anthropophilic dermatophytes are among the fungal agents associated with dermatophytosis in animals in Nsukka Agricultural Zone. These dermatophytes could constitute health risks to humans in contact with the animals.     

Chitin synthase 1 (Chs1) gene sequences of Microsporum equinum and Trichophyton equinum

Chitin synthase 1 (Chs1) genes from Microsporum equinum and Trichophyton equinum were compared with those of the other dermatophytes. The Chs1 nucleotide sequences of these dermatophytes from horses showed more than 80% similarity to those of Arthroderma benhamiae, A. fulvum, A. grubyi, A. gypseum, A. incruvatum, A. otae, A. simii, A. vanbreuseghemii, Epidermophyton floccosum, T. mentagrophytes var. interdigitale (T. interdigitale), T. rubrum and T. violaceum. Especially high degree of nucleotide sequence similarity of more than 99% was noted between the Chs1 gene fragments of M. equinum and A. otae, and those of T. equinum, T. interdigitale and A. vanbreuseghemii, respectively. The phylogenetic analysis of their sequences revealed that M. equinum was genetically very close to A. otae and T. equinum to A. vanbreuseghemii. A molecular analysis of Chs1 genes will provide useful information for the genetic relatedness of M. equinum and T. equinum and confirm the value of DNA sequencing in identification of these two dermatophytes.     

Dermatophytozoonoses in Italy

The pattern of human dermatomycoses has changed in Italy during this century, as a progressive escalation of zoophilic dermatophytes over anthropophilic dermatophytes has been experienced: dermatophytozoonoses now prevail over other dermatophytoses (by anthropophilic and geophilic mycetes). Urban dermatophytozoonoses are caused mainly byMicrosporum canis and are an important problem in young people in cities. Many cats and dogs are symptomless carriers of the fungus. Rural dermatophytozoonoses are caused byTrichophyton verrucosum andT. mentagrophytes. They are an important economic problem in calf, rabbit and laboratory animal farms. They are an occupational disease of agricultural workers: family members may also be affected.

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Kurzfassung Im letzten Jahrhundert hat sich das Vorkommen von Dermatomykosen bei Menschen in Italien sehr verändert, seitdem man festgestellt hat, dass die zoophylen Dermatophyten die Uberhand über die antropophylen gewinnen, d.h. augenblicklich gibt es mehr Dermatophytozoonosen als andere, von antropophylen und geophylen Pilzen hervorgerufene Dermatophytosen. Die in Städten vorkommenden Dermatophytozoonosen werden hauptsächlich von Microscarum canis bewirkt; sie stellen ein wichtiges Problem für die Stadtjugend dar. Viele Katzen und Hunde sind symptomlose Träger dieser Pilze. Die Dermatophytozoonosen ländlicher Gebiete werden durchTrichophyton verrucosum undT. mentagrophytes hervorgerufen. Sie stellen ein ökonomisches Problem für die Aufzucht von Kälbern, Kaninchen und Labortieren dar. Sie müssen ebenfalls als Berufskrankheit der Landarbeiter angesehen und können auch auf Familienmitglieder übertragen werden.

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Resume Le tableau des dermatomycoses s'est modifié en Italie au cours de ce siècle au fur et à mesure qu'on constatait que les dermatophytes zoophiles prenaient le pas sur les anthropophiles: les dermatophytozoonoses l'emportent actuellement sur les cutres dermatophytoses (mycètes anthropophiles et géophiles). Les dermatophytozoonoses urbaines sont causées principalement parMicrosporum canis et constituent un problème important chez les jeunes dans les villes. Beaucoup de chats et chiens sont des porteurs asymptomatiques du champignon. Les dermatophytozoonoses rurales sont provoquées parTrichophyton verrucosum etT. mentagrophytes. Elles représentent un problème économique important chez le veau, le lapin et dans les élevages d'animaux de laboratoire. Elles constituent une maladie professionnelle des travailleurs agricoles; les membres de leur famille peuvent être également affectés.

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Riassunto Nel corso di questo secolo la tavola delle dermatomicosi umane si è modificata in Italia a seguito di un progressivo aumento dei dermatofiti zoofili in relazione e quelli antropofili: le dermatofitizoonosi attualmente sono più frequenti delle altre dermatofitosi (miceti antropofili e geofili). Le dermatofitozoonosi urbane sone causate principalmente dalMicrosporum canis e costituiscono un problemaeconomico importante per la popolazione giovane della città. Molti gatti e cani sono portatori asintomatici di questo fungo. Le dermatofitozoonosi rurali sono provocate dalTrichophyton verrucosum e dalT. mentagrophytes. Esse rappresentano un problema importante per il vitello, il coniglio e per gli allevamenti di animali da laboratorio e costituiscono una malattia professionale per i lavoratori agricoli e i membri delle loro famiglie.

     

Dermatophytes in clinically healthy dogs and cats

The hair and skin of 300 clinically healthy animals, 268 dogs and 32 cats, were examined mycologically. The method described by Mariat and Tapia (1966) was used for the examination, along with square pieces of the fitted carpet Kovral. The dermatophytes were isolated in 12 samples, all from the material taken from dogs. Trichophyton mentagrophytes was isolated six times, Microsporum canis four times, Trichophyton gallinae once, Trichophyton rubrum once. The origin of the dermatophyte Trichophyton gallinae, found in a village dog, was not determined. In one case of occurrence of the dermatophyte Trichophyton mentagrophytes in a dog the dermatophyte was probably transmitted from man to the dog. Microsporum canis was not proved to be the most frequent dermatophyte in dogs or cats in this country.     

Prevalence and Potential Risk Factors of Dermatophytosis in Arabian Horses in Egypt

The objective of the present study was to verify the prevalence and the risk factors associated with dermatophytosis in Arabian horses. For this purpose, a total of 457 Arabian horses in 15 farms were examined. A questionnaire was constructed to include the hypothesized risk factors. Fungal isolation and identification for each horse were carried out by standard microbiological procedures. Logistic regression analysis was used to evaluate the risk factors on both animal and farm levels. Trichophyton spp. was recovered from 50 horses and Microsporum spp. from 27 cases. Trichophyton equinum was more prevalent than Trichophyton mentagrophytes (45 vs. 4) and Trichophyton tonsurans (45 vs. 1). However, Microsporum canis was more prevalent than Microsporum gypseum (21 vs. 5) and Microsporum audouinii (21 vs. 1). On horse level, final multivariate logistic regression analysis showed that there was a significant association between dermatophytosis and horse' age (P < .05; odds ratio [OR]: 1.07; 95% confidence interval [CI]: 1.0–2.69), poor grooming practice (P < .05; OR: 57.11; 95% CI: 2.47–13.44), moist condition (P < .05; OR: 42.77; 95% CI: 2.0–25.18), and farm size (P < .05; OR: 1.06; 95% CI: 1.00–7.05). However, on the farm level, farm size of >30 horses was the risk factor (P < .05; OR: 1.0; 95% CI: 1–3.03). In conclusion, the present results indicate existance of dermatophytosis in Arabian horses. Identification of the potential risk factors associated with the disease may be helpful to construct the ideal preventive measures.     

Immunization with Trichophyton verrucosum Vaccine in Hunter/Jumper and Dressage Horses with Naturally Occurring Trichophyton equinum Infection: A Prospective,Randomized, Double-Blinded,Placebo-Controlled Clinical Trial

The aim of the current study was to investigate the efficacy of Trichophyton verrucosum vaccine in hunter/jumper and dressage horses with trichophytosis caused by Trichophyton equinum (cross immunity). A total of 25 hunter/jumper and dressage horses between the ages of 2 and 14 years, naturally infected with Trichophyton equinum, were enrolled and randomly assigned to either a placebo or an intramuscular lyophilized Trichophyton verrucosum vaccine group. Clinical evaluations were done by the same investigator, who scored clinical healing at the beginning, during, and at the end of the treatment and was blinded to allocation to the groups. At the end of the trial, vaccine treatment significantly decreased the investigator's clinical scores (P < .001), and no significant changes were detected in the placebo treatment group. In all of the horses vaccinated, the lesions improved gradually within 7 to 12 days after vaccination. Complete clinical remission was detected within 28 to 42 days, and all treated horses became culture negative within 25 days of starting treatment. No clinical healing was observed in nine untreated control horses throughout the study. No recurrence was observed in treated horses within 10 months after therapy. Results of the current study indicate that inactivated Trichophyton verrucosum vaccine may be a safe and effective therapy for horses with Trichophyton equinum infection.     

Pets as the main source of two zoonotic species of the Trichophyton mentagrophytes complex in Switzerland, Arthroderma vanbreuseghemii and Arthroderma benhamiae

In cases of highly inflammatory dermatophytosis in humans, it is important to identify the possible source of animal transmission in order to prevent recurrence, family outbreaks or rapidly progressing epidemics. A survey of dermatophytes in pets during a 14-month period in Switzerland revealed, in addition to Microsporum canis , two different species of the Trichophyton mentagrophytes complex, Arthroderma benhamiae and Arthroderma vanbreuseghemii , all causing inflammatory dermatophytoses. Arthroderma benhamiae was only and frequently isolated from guinea pigs. Arthroderma vanbreuseghemii was isolated mainly from European short hair cats, but also from dogs and in one case from a pure-bred cat. Ninety-three percent of the cats carrying A. vanbreuseghemii were hunters and all had skin lesions. In contrast, cats with skin lesions that were strictly indoors were found to be almost exclusively infected by M. canis . Therefore, it can be suspected that infection with A. vanbreuseghemii occurred during hunting and that the natural source of this dermatophyte is either soil or an animal other than the cat, most probably a rodent.     

Fungal flora of the coat of pet cats

The fungal flora of the coat of 172 healthy pet cats was examined qualitatively. Fungi were isolated from 136 (79%) of the 172 cats. Fifteen genera were isolated; 13 are commonly regarded as saprophytes, and 2 (Microsporum and Trichophyton) are commonly regarded as pathogens. Aspergillus, Alternaria, Penicillium, and Cladosporium spp were the most frequently isolated saprophytes. Dermatophytic fungi, including Microsporum gypseum (n = 1), M vanbreuseghemii (n = 1), and Trichophyton rubrum (n = 14), were recovered from 16 cats. Microsporum canis was not isolated from any cat during this study.     

STUDIES ON THE PREVALENCE OF RINGWORM AMONG HORSES IN RACING AND BREEDING STABLES

A survey of 568 horses in training and 2,535 horses on breeding farms has shown 32 percent of the horses in training to be clinically affected while only 1.1 percent of breeding horses were affected with pathogenic dermatophytes. The majority of lesions on racing horses were located on the girth areas. Trichophyton equinum var. autotrophicum, M. canis and M. equinum were found to be restricted to racing horses only. M. gypseum occurred in racing, riding and breeding horses.     

Isolation of keratinophilic fungi from the floors of private veterinary clinics in Italy

To evaluate the presence of keratinophilic fungi in the environment, 400 samples were collected from the floors of 50 private veterinary clinics using 55-mm-diameter contact plates, containing mycobiotic agar. After incubation for 15 days at 25°C, the following species were isolated: Microsporum canis, Trichophyton terrestre, Chrysosporium keratinophilum, Chrysosporium sp., Microsporum gypseum, Trichophyton ajelloi, Chrysosporium tropicum, Trichophyton mentagrophytes, Chrysosporium state of Arthroderma tuberculatum and Chrysosporium pannorum. It is concluded that the keratinic material shed by infected pets may contribute to the development and propagation of dermatophytes and related fungi in veterinary clinics. Therefore, such veterinary clinics may represent sites where pets and humans are exposed to risk of infection with keratinophilic fungi from the environment.     

Severe dermatophytosis due to Trichophyton mentagrophytes var. interdigitale in flocks of green iguanas (Iguana iguana)

Objective : To describe the clinical, mycological, histopathological and molecular findings in green iguanas (Iguana iguana) affected with severe dermatophytosis in selected flocks near Tehran, Iran. Materials and Methods : Samples were collected from the scales of skin lesions and tested with standard mycological methods and dermatophyte‐specific PCR amplification analysis using the primer pair for the chitin synthase 1(CHS1) gene. Results : All iguanas were definitively diagnosed with dermatophytosis using both traditional and molecular diagnostic methods. PCR fingerprinting profiles using simple repetitive (GACA)4 primers showed that all diagnosed iguanas had the same pattern profile. Intraspecific variability was not observed for these isolates. Oligonucleotide sequencing of CHS1 gene PCR products confirmed Trichophyton mentagrophytes var. interdigitale as the infectious agent. Clinical Significance : These results suggest that (GACA)4‐based PCR has utility both as a simple and rapid method for identification of dermatophyte species and for differentiation of T. mentagrophytes variants.     

Isolation of dermatophytes from domestic animals in Norway

The examination of 2066 skin scrapings from domestic animals in the period from July 1981 to June 1984, revealed dermatophytes in 439 samples. Dermatophytes isolated were: M. canis in dog, cat, cattle, horse, swine, goat, rabbit and hamster, M. equinum in dog and horse, M. gypseum in horse, T. equinum in horse and cattle, T. mentagrophytes in dog, cat, cattle, horse, guinea pig and rabbit, T. verrucosum in cattle and E. floccosum in dog.     

Recovery of dermatophytes in pet grooming tools from veterinary clinics and pet grooming salons

Objectives : Fomites such as brushes and clippers are known to be potential risk factors for the transmission of dermatophytes between pet animals. The aim of this study was to investigate this risk by examining those grooming implements for the presence of any viable dermatophytes. Methods : For this purpose, samples from 235 pieces of grooming equipments and swab samples from the surface of the 14 grooming tables were taken from 41 veterinary clinics and 3 pet grooming salons. Results : Trichophyton tonsurans was isolated from two clipper blades from one veterinary clinic and Microsporum canis were isolated from three clipper blades and one toothbrush from another clinic. Clinical Significance : This study shows that current disinfection protocols and grooming procedures of the veterinary clinics and pet grooming salons appear to be adequate.     

Experimental medication of equine ringworm due to Trichophyton equinum var. autotrophkum

SUMMARY Twelve medicaments were tested for their efficacy in the treatment of Trichophyton equinum var. autotrophicum; povidone iodine, thiabendazole ointment, captan ointment and Burroughs Wellcome Ringworm Ointment gave satisfactory results but their usefulness may be limited for treatment of large numbers of horses. Aqueous washes containing 0.5% hexetidine or 0.3% chloramine-T did not prevent fungi being isolated from lesions for up to 7 days after treatment. Similarly neither etisazole nor thiabendazole suspension prevented fungi from being isolated from lesions for up to 15 days after treatment. Commonly used aqueous solution of 2.5% lime sulphur and 2% captan were least successful, as fungi could still be isolated from lesions for up to 30 days after treatment. The need to treat large numbers of horses may dictate the use of such solutions rather than ointments because of ease of application and cost factors. Treatments consisting of 10% nystatin ointment, 10% iodine fortis, 10% Medol and a proprietary ointment, Queensland Itch Dressing, were not satisfactory. Clinical appraisal and a scratch test must be used together to evaluate progress of treatment. Mass medication of large numbers of horses should be primarily aimed at reduction of spread of infection; normal hair growth should not be used as an indication of the removal of infective agents in the hair as regrowth was altered very little by medication. Hence assessments of cure on the basis of regrowth of hair alone are of dubious value.     

Microsporum canis: Inapparent carriage by cats and the viability of arthrospores

A total of 181 dermatologically healthy pet cats from 177 different households, attending a veterinary clinic, were sampled for the presence of dermatophytes by a modified MacKenzie hair brush technique. Microsporum canis was the only dermatophyte recovered and was isolated from four cats (2.2 per cent) from four different households. In addition to clinical details, owners were questioned about the environment and management of all the cats sampled. The data regarding the cats from which M canis was recovered showed little variation from that of the culture-negative cats except that all four cats were from multi-cat (more than two cats) households, whereas only 35 per cent of the culture-negative cats were from a similar environment. The viability of M canis in infected feline hairs stored at room temperature was maintained for between 13 and 18 months.     

Keratinopathogenic mould fungi and dermatophytes in healthy and diseased hooves of horses

Specimens of hoof horn from 187 horses were examined for a possible relationship between clinically affected hooves and the occurrence of pathogenic fungi. Specimens were taken from the coronary band and from the stratum externum and medium of the coronary horn and transferred on to Sabouraud dextrose agar, with and without cycloheximide, and incubated at 28 degrees C. Dermatophytes and mould fungi were identified by their macroscopic and microscopic characteristics. The 732 isolates could be assigned to 26 species of moulds, two different species of the dermatophyte Microsporum and three different species of the dermatophyte Trichophyton. Depending on their pathogenic potential they were assigned to three groups: (i) fungi known to be keratinopathogenic (Acremonium blochii, Alternaria alternata, Alternaria chlamydospora, Geotrichum candidum, Microsporum ferrugineum, Microsporum gypseum, Scopulariopsis brevicaulis, Trichophyton species, Trichophyton mentagrophytes, Trichophyton sch?nleinii, 57 isolates), (ii) a group of uncertain pathogenicity (223 isolates), and (iii) a group of non-pathogenic species (452 isolates). Eighty per cent of the samples from horses with hoof horn lesions and 66.7 per cent of the samples from horses with slightly affected hoof horn contained fungi of the keratinopathogenic group, whereas only 8.9 per cent of the samples from horses with healthy hoof horn contained fungi of this group. There were no significant correlations between the clinical data and the age, sex or breed of the horses or their bedding and hygiene. Twelve species of fungi were isolated from the air in the horses' stables, but none of them belonged to the keratinopathogenic group.     

KERATINOPHILIC FUNGI ON FOUR ANIMAL GROUPS

Four surveys were conducted on different animal groups in the metropolitan area of Perth. Microsporum canis was the only fungus isolated from cats and was prevalent in these animals. Dermatophyte infections in dogs were less common and were caused by M. canis, M. gypseum and Trichophyton mentagrophytes. T. mentagrophytes was isolated from laboratory guinea pigs but not from native animals.     

Ringworm in dogs and cats

Ringworm is an uncommon disease of dogs, but cats, especially the longhaired breeds, are more frequently infected. Of the several dermatophytes involved, Microsporum canis causes 94 per cent of ringworm in cats and 65 per cent in dogs. This species is highly contagious for man but the true incidence of human infection is unknown. Ringworm caused by M canis usually responds readily to treatment, but when the infection establishes in a colony of cats, eradication can be difficult and expensive. Other forms of ringworm in dogs and cats are caused by dermatophytes acquired from wild animals, mainly small rodents such as mice and voles. This is an uncommon and trivial disease of cats, but some infections in dogs can be remarkably persistent and difficult to resolve.     

Presence of opioid growth factor and its receptor in the normal dog,cat and horse cornea

Objective To determine if opioid growth factor (OGF, [Met⁵]enkephalin) and its specific receptor (OGFr) are present in normal cat, dog and horse cornea. Animals studied Normal dog, cat and horse. Procedure Corneas were obtained from animals euthanized for reasons unrelated to this project. One cornea from each of three normal cats, dogs and horses was evaluated. The right or left cornea from each animal was chosen randomly. Corneas were harvested and placed in corneal storage media for transport to The M.S. Hershey Medical Center of The Pennsylvania State University where immunocytochemistry techniques were used to demonstrate the presence and location of OGF and OGFr. Tissues were rinsed in Sorenson's phosphate buffer, immersed in 20% sucrose in buffer and then snap frozen in isopentane. Corneas were then embedded in OCT medium and 15 µm cryostat sections were created. Presence of OGF was determined by using a polyclonal antibody to [Met⁵]enkephalin and assessing immunoreactivity. OGFr presence was determined by using a previously characterized rabbit polyclonal antibody to the receptor. Results OGF and OGFr were identified in large quantities in the corneal epithelium of all three species. Conclusion Opioid growth factor and its specific receptor are present in the corneal epithelium of normal cats, dogs and horses. OGF is present in the cornea of many species and its presence is theorized to inhibit healing of injured tissue.