Prevalence of Pseudomonas associated otitis externa in dogs

Introduction

The disorder of sensorineural impaired hearing is regarded as incurable. It comprises hearing loss brought on biologically by otitis externa and hearing loss brought on physically by noise. Otitis externa, often referred to as external ear canal inflammation is one of the most frequently seen clinical illnesses, affecting 5 to 20% of dogs (Rougier et al., 2005) [15] . Further, it is a common multifactorial chronic or recurrent illness with a prevalence as high as 20% in dogs (Korbelik et al., 2019) [10] . The causes of otic illness, including otitis externa, are multifaceted, and microorganisms are a major contributor (Hariharan et al., 2006) [7] . In general practice, this condition in dogs is a fairly prevalent clinical issue that is also quite difficult to treat, particularly when instances are recurring. Otitis externa may be caused by a variety of microorganisms, such as Gram-positive cocci or Gram-negative rods (Barnard and Foster, 2017) [2] . Clinical signs commonly associated with otitis externa include frequent head shaking, itching of the ears, foul smell coming from the ear, redness, hair loss around the affected area, and self-trauma to the region around the ear. Animals may also show sensitivity when the head is touched, discharge within the ear canal, development of an aural hematoma, and ulceration of the external ear canal. If the ear canal is thicker, rigid, and less flexible due to a persistent illness, patients may feel discomfort especially when the canal is palpated (Pye, 2018) [14] .

Materials and Methods

The present study was carried out in the College of Veterinary Science and A.H., Anjora, Dau Shri Vasudev Chandrakar Kamdhenu Vishwavidyalaya, Durg, Chhattisgarh. Dogs seeking therapeutic intervention for varying ear affections presented to the Teaching Veterinary Clinical Complex, College of Veterinary Science and Animal Husbandry, Anjora, Durg (C.G.) and various Government Veterinary Hospitals and Private Pet Clinics in and around Durg were taken up for the present study. Relevant information regarding age, breed, sex, date of sample collection, pattern of lesion and symptoms in dogs affected with otitis externa were recorded.

Prevalence was determined by calculating the proportion of dogs diagnosed with otitis externa relative to the total number of dogs examined. The occurrence of ear disease was further analyzed according to age groups and breed categories.

Results and Discussion

Prevalence of otitis externa in dogs

A total screening of 263 cases presented at Teaching Veterinary Clinical Complex, College of Veterinary Science and Animal Husbandry and various Government Veterinary Hospitals and Private Pet Clinics in and around Durg district, revealed that 52 dogs had clinical cases of otitis externa, with an overall prevalence of 19.77%. The prevalence of otitis externa in dogs is shown by the data provided in Table 1 and Fig. 1.

In the present study it was found that out of 52 dogs affected with otitis externa, 19 dogs harboured Pseudomonas which accounted for 36.54% cases of otitis externa shown in Fig. 2. Pseudomonas is a gram-negative rod and is not usually isolated from a normal dog`s ear. The of present study are in accordance with those stated by Korbelik who have reported the prevalence rate of otitis externa as 20% in dogs. The prevalence of otitis externa in dogs has also been reported to be around 20% in clinical cases of dogs (Angus, 2004; Martino et al., 2016 and Choi et al. 2018) [1,11,4] . In contrast to present findings, lower prevalence of otitis externa 8.70% in dogs has been reported by Topala et al. (2007) [17] while O'Neill (2021) [23] have reported prevalence of otitis externa in dogs to be 7.30%. The presence of other etiological agent, parasites, ambient temperature and humidity of the particular geographical area, allergies, co-occurring diseases like dermatological and endocrine disorders, maintenance of hygiene and adoption of regular cleaning practices may all play a role in the differences between the findings of other studies and the results of the current study.

Age wise prevalence of otitis externa in dogs

The rate of prevalence of otitis externa in dogs based on the age has been presented in Table 2 and Fig. 3. The age wise prevalence was recorded as 7.6%, 15.38%, 30.8% and 46.2% in dogs of age group < 1 year, 1 to 3 years, 3 to 5 years and > 5 years respectively. Highest prevalence of otitis externa (46.2%) was observed among dogs older than five years of age. A number of studies carried out by various workers have also documented that dogs between 5-8 years of age were mostly affected. Topala et al. (2007) [17] reported that 16.2% dogs between 1-2 years, 28.2% dogs between 2-5 years and 33.4% dogs between 5-8 years were affected with otitis externa. Similarly, observation made by Dziva et al. (2015) [5] also indicated that the otitis externa appears to occur more in older than in younger dogs. The findings of our study indicate that all age groups of dogs may suffer from otitis externa. However, frequency of occurrence is higher in dogs which have attained age of more than five years. The higher rate of prevalence could be correlated initially with activity of sebaceous gland which is under the influence of androgen hormones but in subsequent stage of age, it might be correlated with the reduction in the immunity and initiation of degenerative process. However, Nair (2004) [12] reported higher incidence of otitis externa in dogs aged between 1-6 years. Similarly, Fernandez et al. (2006) [6] and Roy et al. (2018) [16] observed a higher incidence of otitis in dogs between 2 and 5 months of age. In contrast to these reports, Zur et al. (2011) [19] have opined that there is no correlation of age in dogs for occurrence of otitis externa.

Breed wise prevalence of otitis externa in dogs

The breed wise prevalence of otitis externa has been represented in Table 3 and Fig. 4. The obtained data of the present study revealed that there was uneven distribution in various breeds of the dogs in relation to occurrence of otitis externa. The reasons of this uneven rate of prevalence could be due to various factors viz. anatomy of ear canal and pinna, moisture, trauma, hairy or pendulous ear etc. During the present study, the highest occurrence of otitis externa was observed in German shepherd (30.8%) followed by Spitz (15.4%), Labrador retriever (11.6%), Rottweiler (9.6%), Pug (7.6%), Doberman (7.6%), Cocker spaniel (5.7%), Dalmatian (3.9%), Saint Bernard (3.9%) and others (3.9%). The findings of the present study are in accordance with the reports of Kiss et al. (1997) [9] who have also recorded the highest incidence of otitis externa in German shepherd (28.5%) followed by Cocker spaniel (19%), Cross breed (19.9%) and Miniature poodle (8.3%). Similarly, Chaudhary and Mirakhur (2002) [3] also recorded higher (31.14%) incidence of otitis in German shepherd breed followed by Spitz breed (29.87%). Contrary to the findings of present study, Fernandez et al. (2006) [6] reported higher incidence of otitis externa in Poodle (30.19%) followed by Mongrel (26.42%), Cocker spaniel (16.98%) and German shepherd (9.49%). Higher incidence of otitis externa was reported in our study in German shepherd breed might be due to hyperactivity of cerumen producing glands. However, Yoshida et al. (2002) [18] have reported no significant difference among breeds for occurrence of otitis externa in dogs.

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