Occurrence of Malassezia dermatitis in Dogs in and around Navsari (Gujarat)

Introduction

The skin, as the body's largest organ, acts both anatomically and physiologically to separate the internal environment from the external. Its condition is a reflection of overall bodily health and can be influenced by various internal and external factors (Muller and Kirk, 2013) [1] . Managing skin diseases in dogs is challenging due to their chronic nature, causing discomfort for animals and anxiety for owners. Accurate identification and treatment are essential to prevent chronic illness and ensure complete recovery. Ongoing veterinary care is often necessary to manage these conditions effectively. Malassezia pachydermatis, formerly known as Pityrosporum canis, is a common commensal organism found in the anal sacs, anus, auditory canal, and skin of both healthy and sick dogs. It is a nonmycelial, unipolar, lipophilic budding yeast. Belgian veterinarian Dufait first identified this organism as a disease-causing agent (Kumari, 2007) [2] . Malassezia pachydermatis, part of the normal canine cutaneous microbiota, acts as a facultative pathogen when conditions like cutaneous inflammation and altered sebum production favor its spread. These changes can lead to yeast dermatitis in any age, breed, or season of dogs (Nardoni et al., 2004) [26] . Diagnosing it as a pathogen can be challenging. Certain dog breeds, such as the German Shepherd, Poodle, Cocker Spaniel, West Highland White Terrier, and Daschund, have a higher predisposition than others (Mircean et al., 2010) [3] . In addition to food allergies, elevated relative humidity and extreme outside temperatures may raise the incidence of disease among young ones (Carlotti, 2006) [14] . Malassezia dermatitis in dogs can present as either localized or generalized, marked by intense pruritus, alopecia, hyperpigmentation, lichenification, and thickened skin. Additional symptoms include erythema, scaling, rancid odor, greasiness, and hyperkeratinization (Ganguly et al., 2013) [15] . Commonly affected areas are the muzzle, lips, ears, ventral neck, axilla, and ventral body, and it may be secondary to other conditions like endocrinopathies and skin neoplasms (Mircean et al., 2010) [3] .

Diagnosing Malassezia infections requires yeast presence confirmation through methods like culture analysis, PCR, and cytological examinations of tape and slide impressions (Kumari, 2007) [2] . PCR effectively identifies Malassezia species (Guillot et al., 2000) [16] . Sequencing methods, including CHS2, LSU, ITS-1, and IGS-1 regions of ribosomal RNA, analyze genetic diversity among Malassezia species (Guillot et al., 1997) [17] .

Materials and Methods

A. Location and place of work

The proposed study was carried out for six months i.e., from February 2024 to July 2024 at the Department of Veterinary Medicine, Veterinary Clinical Complex (VCC), College of Veterinary Science and Animal Husbandry, Kamdhenu University, Navsari, Gujarat. Geographically, Navsari is located at 20.95°N 72.93°E. It has an average elevation of 9 meters, or 30 feet, above sea level. The city is located in southern Gujarat and near the Purna River, within a few kilometers of the river's delta, which is west of the city and empties into the Gulf of Khambhat. The climate of the region is humid and tropical with heavy rainfall.

B. Screening

For this study, a total of 895 dogs of either sex, irrespective of breed and age group, brought to the Veterinary Clinical Complex, College of Veterinary Science and Animal Husbandry, Navsari and in and around Navsari were carefully screened based on history and presence of clinical symptoms indicative for Malassezia dermatitis viz., erythema, pruritus, hyperpigmentation, offensive odour, scales, crusts, alopecia, lichenification, etc. Out of 895 dogs, 140 dogs with dermatological disorders were screened for Malassezia dermatitis. For confirmation of Malasseziosis, dogs with dermatological disorders were subjected to cytological examination using Acetate tape impressions, and Glass slide impression smears. The prepared smears were then stained for one minute with a drop of new methylene blue by the Diff-Quick method. After that, the stained slides were viewed using an oil immersion objective. The presence of more than five organisms per oil power field (x1000) was considered positive for the study.

C. Statistical analysis

The collected data was analyzed by Chi-square test and Paired t-test using IBM SPSS statistical software version 27.0.

Results and Discussion

A. Overall occurrence

An epidemiological study was conducted on dogs to know the occurrence of Malassezia dermatitis in dogs in and around Navsari during a period of six months i.e. from February to July 2024. A total of 895 dogs were presented over the period of time, out of which 140 dogs had a history and signs of pruritus, erythema, alopecia, hyperpigmentation, offensive greasy rancid odour and various visible signs. The overall occurrence of dermatological disorders among the dog population in and around Navsari was 15.64%. A detailed laboratory investigation did not confirm the causative agent of dermatitis in 75 cases. Out of them, 73 (52.14%) and 2 (1.43%) were suspected of atopic dermatitis and flea allergy dermatitis, respectively, depending on their type and distribution of lesions. The overall occurrence of Malassezia dermatitis was 4.47% among all dogs presented over a period of time, while the specific occurrence of Malassezia dermatitis among dogs with different dermatological disorders was 28.57%. The present study's results are in close agreement with the findings of Kumar et al. (2011) [24] and Suresh and Kumar (2017) [11] , who reported 30% and 27.78%, respectively. Mircean et al. (2010) [3] and Khosravi et al. (2008) [18] documented a higher prevalence of 37.6% and 50%, respectively. On the lower side prevalence, Daniel (2021) [7] and Saranya (2011) [9] reported 14.70%, 17.19%, and 17.75%, respectively. [19] , Girao et al. (2006) [20] , Saranya (2011) [9] , Seetha et al. (2018) [10] , and Daniel (2021) [7] reported that the majority of dogs affected by M. pachydermatis were aged between 1 and 3 years old. In contrast, Suresh and Kumar (2017) [11] reported higher rates of malasseziosis in dogs older than 8 years. Similarly, Dohre et al. (2021) [8] also found that the prevalence of Malassezia dermatitis increased with age, with higher rates in dogs between 6 and 9 years old. Additionally, Borkar (2014) [ 21] documented that geriatric animal (over 9 years old) had a 63.30% and 11.09% prevalence of Malassezia infection, respectively. However, Nambi (2002) [22] observed more common Malassezia infection in young puppies under one year of age and in geriatric patients, possibly due to poor immune status. On the other hand, found no correlation between Malassezia dermatitis and the age of animals. Carlotti (2006) [14] suggested that elevated relative humidity and extreme outside temperature lead to immunosuppression in young dogs followed by an increase in the occurrence of malasseziosis. So, the tropical and humid environment of South Gujarat might affect the occurrence rate in young animals. Apart from this, other factors like seasonal fluctuations, immune status, geographical variations, and management practices could influence the prevalence of malasseziosis in dogs.

C. Gender-wise occurrence of Malassezia dermatitis in dogs

Out of the total affected dogs with malasseziosis, 27 (67.50%) were males and 13 (32.50%) were females. A non-significant difference was observed in the gender-wise occurrence of Malassezia dermatitis in dogs in and around Navsari. The details are summarized in Table 5. [11] , Seetha et al. (2018) [10] , and Dohre et al. (2021) [8] , all of whom reported a higher occurrence of Malassezia dermatitis in male dogs compared to females. Higher concentrations of androgens in male might contribute to increased sebum production and secretion, making male dogs more susceptible to subclinical Malassezia infection (Dohre et al., 2021) [8] . Conversely, Mauldin et al. (1997), Saranya (2011) [9] , and Daniel (2021) [7] observed a higher prevalence of canine malasseziosis in females. However, Nardoni et al. (2004) [26] , and Girao et al. (2006) [20] found no significant difference in the prevalence of Malassezia dermatitis between the two sexes.

D. Breed-wise occurrence of Malassezia dermatitis in dogs

The occurrence of Malassezia dermatitis was examined in various dogs in and around Navsari. Statistically, no significant difference was observed between breeds in relation to the occurrence of malasseziosis in dogs. The highest prevalence was observed in Labrador Retrievers (32.5%), German Shepherds (20.00%) and other breeds (15.00%) (Including American Bully, Cocker Spaniel, Lhasa Apso, Beagle, Bull Mastiff, Rottweiler, Saint Bernard, Dachshund, Doberman, Pomeranian, Shih Tzu, etc.). Non-descript breeds (12.50%), Pugs (10.00%) and the lowest prevalence were recorded in Golden Retrievers and Cross-breeds (5.00% each), both at 5.00 percent (2 out of 40). The detailed data are presented in Table 6. The findings of the present study align with those of Kumar et al. (2011), Saranya (2011) [9] , Suresh and Kumar (2017) [11] , and Dohre et al. (2021) [8] , all of whom reported a higher prevalence of malasseziosis in Labrador Retrievers. However, these results differ from those of Mircean et al. (2010) [3] , who observed varying prevalence patterns. In contrast, a higher prevalence of malasseziosis in German Shepherds has been reported by Lakshmi and Padmaja (2013) [13] , and Daniel (2021) [7] . The variation in prevalence among different breeds might be due to the popularity and distribution of these breeds in the study's geographic area. The higher rates of malasseziosis in Labrador Retrievers observed in this study likely stem from the breed's popularity and increased representation during the study period.

E. Month-wise occurrence of Malassezia dermatitis in dogs

Skin infections associated with Malassezia dermatitis were reported throughout the year in many part of the world. In the present study, month-wise distribution of malasseziosis revealed no significant variation in the occurrence of disease, however, the highest prevalence of Malassezia dermatitis was observed in July (32.50%), followed by February (17.50%), June (20.00%), and May (15.00%). The lowest occurrences were recorded in March and April (7.50% each). The detailed data are presented in Table 7. The findings of the present study are consistent with previous reports by Daniel (2021) [7] , Suresh and Kumar (2017) [11] , Saranya (2011) [9] , all of whom reported a higher prevalence of Malassezia dermatitis during the summer months. In contrast, observed a relatively higher prevalence of Malassezia dermatitis/otitis in autumn, with rates as high as 52.6%. As discussed earlier, increased relative humidity and environmental temperature provide suitable conditions for the proliferation of yeast. Navsari city is situated in a tropical area just 12 km away from sea and monsoon starts here at the end of June, so an increase in humidity along with warm environmental temperature favours the high occurrence of disease in July month.

Conclusions

The overall incidence of Malassezia dermatitis in dogs in and around Navsari was 4.47%, while the occurrence of dermatological disorders in the screened population was 15.64%. No significant variation between age, sex, breed, and month was observed for the occurrence of Malassezia dermatitis. However, dogs aged between 1-4 years, Labrador Retrievers and male dogs had higher occurrence of disease.

Future Scope

The current study provides valuable insights into the prevalence of Malassezia dermatitis in dogs in Navsari, Gujarat. Future research could focus on examining the association between various risk factors and the zoonotic potential of Malassezia dermatitis. Further comprehensive investigations would help deepen our understanding of this condition and its implications for both canine and human health.

Acknowledgement

AcknowledgementThe authors extend their sincere appreciation to the Dean of the College of Veterinary Sciences and Animal Husbandry (Navsari), Kamdhenu University, Gujarat for providing the necessary facilities to conduct this research.

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