Epidemiological investigation and molecular typing of dermatophytosis caused by Microsporum canis in dogs and cats

Asymptomatic colonization of stray dogs and domestic cats with Trichophyton mentagrophytes II in Northern Iran

BACKGROUND

Despite changes in the epidemiology of dermatophyte infections, the incidence of fungal infections associated with Trichophyton species still remains high among dogs and cats. The objective of the present study was to isolate and characterize dermatophytes from dogs and cats in Iran.

METHOD

From December 2022 to May 2023, skin and hair samples were collected from symptomatic and asymptomatic cats and dogs in Mazandaran, a northern province of Iran. The samples were then inoculated into Mycosel™ Agar. Dermatophyte isolates were identified by sequencing the internal transcribed spacer region. Antifungal susceptibility tests were conducted using the Clinical and Laboratory Standards Institute (CLSI-M38-A3).

RESULT

Of the 250 samples collected (from 200 dogs and 50 cats), 20 (from 19 dogs and one cat) (8.0 %) were positive for dermatophyte growth. Based on sequence and phylogenetic analysis, all isolates belonged to T. mentagrophytes II*. Of these positive samples, 14 (70.0 %), 3 (15.0 %), 2 (10.0 %), and 1 (2.0 %) were isolated from asymptomatic stray dogs, symptomatic stray dogs, symptomatic domestic dogs, and symptomatic cats, respectively. Luliconazole and terbinafine displayed potent activity against all T. mentagrophytes isolates, with Minimum inhibitory concentration (MIC) values of 0.016 µg/ml. Miconazole and griseofulvin demonstrated higher MIC (1 and 8 µg/ml).

CONCLUSION

The present study indicated that T. mentagrophytes II* asymptomatic carriage is frequent in stray dogs in Iran. The potential risk to public health needs to be evaluated However, T. mentagrophytes genotype VIII, considered as an endemic and emerging human pathogenic clone in several countries, was not detected during the present survey.

Dermatophytosis in Companion Animals in Portugal: A Comprehensive Epidemiological Retrospective Study of 12 Years (2012-2023)

Dermatophytosis, commonly referred to as ringworm, is a common superficial fungal infection in companion animals and humans. Between 2012 and 2023, plucked hair and scraped scale samples from domestic dogs and cats with clinical suspicion of dermatophytosis were collected from 355 veterinary medical centres across mainland Portugal. A total of 4716 animal samples were inoculated onto DERM agar, incubated at 25 °C for up to 4 weeks, and periodically examined macro- and micro-scopically to observe and evaluate fungal growth. Of these, 271 samples were removed due to contaminant fungi. Of the 568 positive cultures, the highest number were from the North (48.1%; 95% CI: 44.0-52.2%) and Centre (32.4%; 95% CI: 28.7-36.4%) regions. Microsporum canis was the most frequently isolated species (63.9%), followed by Trichophyton spp. (20.3%) and Nannizia gypsea (formerly Microsporum gypseum) (8.1%). Felines exhibited a higher frequency (17.4%) compared with dogs (9.1%) (p < 0.001). In dogs, the Yorkshire Terrier, West Highland White Terrier, Miniature Pinscher, Dalmatian and Miniature Schnauzer demonstrated a significant predisposition to dermatophytosis (p < 0.05). In cats, the Persian and Scottish Fold breeds were significantly predisposed (p < 0.05). No significant differences were found between sexes (p > 0.05). These findings underscore dermatophytosis as an increasing public health concern due to its zoonotic and contagious nature, providing comprehensive insights into the epidemiology of dermatophytosis in Portugal.

Bovine ringworm - Detection of Trichophyton verrucosum by SYBR-Green real-time PCR

Trichophyton verrucosum is the most commonly dermatophyte involved in cattle ringworm. This work reported a case of bovine dermatophytosis due to Trichophyton verrucosum detected from the clinical sample by SYBR-Green real-time PCR. The strategy was based on the DNA extraction directly from the infected hair followed by real-time PCR and melting-point analysis. A faster and differential diagnosis was observed when compared to the conventional mycological methodology for detection and identification of Trichophyton verrucosum.

First study on molecular epidemiology of dermatophytosis in cats, dogs, and their companions in the Kurdistan region of Iraq

Background and Aim

Dermatophytosis is a zoonotic infection of the hair, skin, or nails in animals and humans caused by dermatophytes fungi. This study aimed to estimate the prevalence of dermatophytosis and its associated factors in cats, dogs, and humans in the Kurdistan region of Iraq.

Materials and Methods

Skin scraping samples were taken from cats, dogs, and humans with or without skin lesions. In total, 271 samples were collected; 133 from cats, 94 from dogs, and 44 from humans. The collected samples were cultured on dermatophyte test media for fungal isolation and molecular identification.

Results

The prevalence of the disease was 44.36%, 40.43%, and 65.91% in cats, dogs, and humans, respectively. Microsporum canis, the most frequently isolated dermatophyte, occurred in 94.92% of cats, 92.11% of dogs, and 100.0% of humans whereas, Trichophyton mentagrophytes was only isolated from 5.08% of cats to 7.89% of dogs. Animals and humans at younger ages were more susceptible to the infection. Males were more susceptible than females among animals, while the reverse was true in humans. Housed cats were at higher risk of dermatophytosis than outdoor-reared cats, whereas outdoor-reared dogs were at higher risk of dermatophytosis than indoor-reared dogs. The affected skin in animals and humans is significantly associated with higher prevalence rates of the disease. Contact with infected cats and dogs was associated with increased infection rates in humans. Patients with a history of coronavirus disease 2019 (COVID-19) were found to be at higher risk of dermatophytosis than those with no history of COVID-19.

Conclusion

Awareness should be raised among people about the zoonotic aspect of the disease, especially among those with COVID-19, to avoid contact with cats and dogs, who are at risk of the disease.

Trichophyton species isolated from asymptomatic patients of the pet-owner pair in Mexico

Background and Purpose:

Superficial mycoses are the fourth most common cause of disease worldwide. It is not surprising that zoonotic transmission occurs to humans due to close contact with different animals, be it companion or farm animals. Therefore, the objective of this study was to determine the presence of asymptomatic dermatophyte carriers in the owner-pet pairs, identify the most common etiologic agents, and find the likely connection between the carrier status of an owner and the presence of dermatophytes in their pets.

Materials and Methods:

From May 2019 to January 2020, 21 cats and 115 dogs with their respective owners were selected for dermatophyte culture. All the dogs and cats included in the study were from the communities of southeastern Mexico. The samples were taken with a cotton swab, which was vigorously rubbed and twisted on the scalp or body of the pet four times and grown on Mycosel Agar. The isolates were identified based on macroscopic and microscopic characteristics. The prevalence of the binomial ranged from 0.73% in pet skin and human hands to 2.2% in human scalp. In humans, the agents were Trichophyton tonsurans and Trichophyton verrucosum, while in pets, a strain of Trichophyton sp was found.

Conclusion:

Different species of dermatophytes were found in the owner/pet pairs, which denotes that coexistence is not related in asymptomatic cases.

Efficacy of cyclic lipopeptides obtained from Bacillus subtilis to inhibit the growth of Microsporum canis isolated from cats

Background and aim

Microsporum canis (M. canis) is a dermatophyte fungal pathogen that causes ringworms. Cats are considered to be a dominant reservoir host enabling M. canis transmission to humans. The concerns of dermatophyte resistance were raised among the usage of antifungal drugs to treat the ringworm. This study aimed to evaluate the fungal activity of cyclic lipopeptides (CLPs) obtained from Bacillus subtilis (B. subtilis) as an alternative method for the inhibition of M. canis growth.

Materials and methods

The culture plate of M. canis from confirmed cats with ringworm infection was provided. The purification of CLP extract, fengycin, iturin A, and surfactin was carried out from B. subtilis by preparative thin-layer chromatography (PTLC) coupled with solid-phase extraction (SPE) methods. Half-maximal effective concentration (EC₅₀) and agar well diffusion assays were performed to determine the efficacy of Bacillus CLP extract, fengycin, iturin A, and surfactin to inhibit the growth of M. canis isolated from cats.

Results

All purified Bacillus substances displayed antifungal activity to control the growth of M. canis when compared with 80% ethanol (control). EC₅₀ values for CLP extract, fengycin, iturin A, and surfactin were 0.23, 0.05, 0.17, and 0.08 mg/mL, respectively. In agar well diffusion assay, the ability of CLP extract, fengycin, iturin A, and surfactin on fungal inhibition had no statistically significant difference at 24 and 48 h after treatment (p < 0.05). However, CLP extract showed a statistically significant difference on M. canis inhibition at 62.21% followed by surfactin with 59.04% at 72 h after treatment.

Conclusion

In vitro, Bacillus CLPs revealed an inhibitory effect on M. canis growth which is a zoonotic pathogen that causes ringworms. This study suggests an alternative approach to control the growth of M. canis using substances obtained from B. subtilis as a biomedicine agent with antifungal activity.

Isolation of Dermatophytes from Infected Stray Dogs in Selangor, Malaysia

Background: Dermatophytosis is one of the most common skin diseases that affects cats and dogs. Geographic factors play an important role in determining prevalence, showing high rates of prevalence in warm and humid environments. Purpose: The aim of this study was to determine the macroscopic and microscopic identification of different types of dermatophytes present on stray dogs. Methods: The design of this study was laboratory-based research. Each sample was collected from an infection site (nail, hair, or skin) that was identified by conducting a physical examination of a stray dog that was infected with fungi. The skin scraping, nail clipping, and fur cutting samples were collected from infected dogs and then cultured on Sabouraud Dextrose Agar (SDA). The cultures were incubated at 26°C for five weeks. The isolates of fungi were then examined macroscopically and microscopically. The Lactophenol Cotton Blue (LPCB) staining technique was used for fungi morphology identification. Results: Overall, the most common type of dermatophytes that affected the dogs were Trichophyton spp. (64.70%), Aspergillus spp. (10.10%), Microsporum spp. (7.20%), and Curvularia spp. (5.60%). Conclusion: This study revealed the most common dermatophyte infections found on stray dogs in Selangor, Malaysia. This study can assist investigators in understanding the prevalence of the dermatophyte burden in stray dogs and help prevent further complication, such as the spread of illness, especially zoonotic infection.

Evaluation of activity and toxicity of combining clioquinol with ciclopirox and terbinafine in alternative models of dermatophytosis

Dermatophytosis is a superficial fungal infection that affects humans and is very common in small animals. The treatment using the most commonly used antifungals is failing, and new therapeutic alternatives are required to combat the resistance of these fungal infections. Previous studies by the group have shown that clioquinol is an important therapeutic alternative in the treatment of dermatophytosis. The object was to conduct studies of antidermatophytic activity and the irritant potential from the double and triple combinations of clioquinol, terbinafine and ciclopirox in ex vivo and in vivo alternative models. To evaluate the irritant potential of antifungal combinations, the alternative HET-CAM method (chicken egg test chorioallantoic membrane) was used. Ex vivo models were used to assess the effectiveness of antifungal combinations, using pig hooves and veterinary fur. Any possible tissue damage was to assess through in histopathology of swine ears. HET-CAM results showed that all combinations can be classified as non-irritating, corroborated by the results of the histopathological evaluation of the pig's ear skin. Only the double combinations managed to remove 100% of the colony-forming units (CFU) formed on the pig's hooves. The clioquinol + terbinafine combination and the triple combination were more effective than clioquinol + ciclopirox in eradicating the preformed biofilm in fur of veterinary origin. These results show the potential of formulations of clioquinol in combination with antifungals for use in humans and in the veterinary field to combat dermatophytosis, as an important alternative therapy, for use in the near future.

Dermatophytosis in companion animals: A review

Dermatophytosis, a zoonotic disease, is caused by fungi of three main genera, namely, Micropsorum, Trichophyton, and Epidermophyton. Specific lesions of dermatophyte infections are localized in the face, legs, and/or tail. Skin lesions in infected animals demonstrate localized alopecia, erythema, and crust, which are more commonly known as ringworm. Factors that affect dermatophytosis include the dermatophyte species; virulence factors of the agent; and the immune status, age, and sex of the host. High levels of cortisol and pro-inflammatory cytokines have also been reported to play an important role in dermatophyte infection. This review aims to explore and understand factors that affect dermatophyte infection with an emphasis on the prevalence, clinical signs, pathogenesis, immune response, and the roles of cortisol and cytokines in companion animals infected by a dermatophyte.

A One Health Perspective on the Human-Companion Animal Relationship with Emphasis on Zoonotic Aspects

Over time the human-animal bond has been changed. For instance, the role of pets has changed from work animals (protecting houses, catching mice) to animals with a social function, giving companionship. Pets can be important for the physical and mental health of their owners but may also transmit zoonotic infections. The One Health initiative is a worldwide strategy for expanding collaborations in all aspects of health care for humans, animals, and the environment. However, in One Health communications the role of particularly dogs and cats is often underestimated.

OBJECTIVE

Evaluation of positive and negative One Health issues of the human-companion animal relationship with a focus on zoonotic aspects of cats and dogs in industrialized countries.

METHOD

Literature review.

RESULTS

Pets undoubtedly have a positive effect on human health, while owners are increasing aware of pet's health and welfare. The changing attitude of humans with regard to pets and their environment can also lead to negative effects such as changes in feeding practices, extreme breeding, and behavioral problems, and anthropozoonoses. For the human, there may be a higher risk of the transmission of zoonotic infections due to trends such as sleeping with pets, allowing pets to lick the face or wounds, bite accidents, keeping exotic animals, the importation of rescue dogs, and soil contact.

CONCLUSIONS

One Health issues need frequently re-evaluated as the close human-animal relationship with pet animals can totally differ compared to decennia ago. Because of the changed human-companion animal bond, recommendations regarding responsible pet-ownership, including normal hygienic practices, responsible breeding, feeding, housing, and mental and physical challenges conforming the biology of the animal are required. Education can be performed by vets and physicians as part of the One Health concept.

Species distribution of the main aetiologic agents causing skin dermatophytosis in Colombian patients: A 23-year experience at a Mycological Reference Center

BACKGROUND

Dermatophytosis is one of the most frequent superficial mycoses in the world.

MAIN AIM

To describe the cases of skin dermatophytosis and its main aetiologic agents in patients referred to a Mycological Reference Laboratory in Medellín, Colombia.

METHODS

A retrospective study was carried out with records of patients referred between 1994 and 2016 to the Corporación para Investigaciones Biológicas (CIB), Medellín-Colombia, because of clinical suspicion of skin dermatophytosis.

RESULTS

Of a total of 5628 clinical records of patients with suspicion of skin dermatophytosis analysed, 2780 (49.4%) had a proven or probable dermatophytosis diagnosis, 2774 cultures were performed, and aetiologic agents were isolated in 2576 samples (92.9%). The most frequently isolated aetiologic agents were Trichophyton rubrum (44.3%), followed by Trichophyton mentagrophytes complex (33.3%), Epidermophyton floccosum (12.4%), Nannizzia gypseum complex (5.7%, formerly Microsporum gypseum), Microsporum canis (3.5%) and Trichophyton tonsurans (0.8%). The most frequent clinical forms were tinea pedis (72.7%) and tinea corporis (12.7%). In addition, a group of patients (0.9%) developed mixed infections by two dermatophyte agents and another (4.1%) developed infections in more than one anatomical site.

CONCLUSIONS

The results of the present study are coherent with previous reports where T rubrum and T mentagrophytes complex were the main causative agents of dermatophytosis. However, the increased incidence of N gypsea complex over M canis is worth highlighting.