Epidemiological Aspects of Renal Disorders in Dogs at South-Saurastra Region of Gujarat- A Prospective Study

The body’s essential kidneys carry out a variety of tasks to keep the system in balance. Because of their distinct anatomical and physiological characteristics, as well as their transport tasks and high metabolic rates, kidneys are vulnerable to ischemia and toxicants. In dogs, renal dysfunction is a prevalent issue that contributes significantly to morbidity and mortality. It always requires emergency attention and treatment since it is life-threatening. The loss of over 75% of the kidney’s functional unit (nephrons) is attributed to renal failure. It is frequently too late to save the canines when they receive a diagnosis.
       
Renal diseases are most common clinical problems, occurring upto 2-5% of dogs (Katoch et al., 2017) and considered as the third leading cause of death (Sosnar et al., 2003). Incidence has been ever increasing as seen from by various authors reporting renal failure as 1.16 per cent (Chand et al., 2024), 2.65 per cent (Pathak et al., 2023), 11.9 per cent (Sosnar et al., 2003) and 12.03 per cent (Nabi et al., 2018). According to a study, renal failure is observed at a high rate of 49.58 per cent in dogs of geriatric age group i.e. more than 8 years of age (Tufani et al., 2015). Differences in study design may also explain the variation in occurrence rates (Chand et al., 2024).
       
The clinical manifestations of renal disorders are multifaceted, which can lead to challenges in diagnosis. The prevalence of various clinical indicators in renal disorders is contingent upon the level of renal impairment, the presence of azotemia and the overall health status of affected canines. Renal disorders have become a significant threat to dogs in recent years due to the challenge of timely detection. Often, these disorders are only identified once irreversible kidney damage has occurred, resulting in substantial illness and death (Chand et al., 2024). Epidemiological database regarding renal disorders in dogs is lacking in this area. Hence, this is the first ever study planned to generate baseline database, key trends and challenges in the diagnosis and management of renal disorders in this geographical area, offering insights for veterinary practitioners and public health initiatives.

A total of 2850 clinical cases of dogs presented at Veterinary clinical Complex (VCC), College of Veterinary Science and Animal Husbandry, Kamdhenu University, Junagadh, Gujarat, India during the study period September 2022 to August 2023 were screened for renal disorders.
 
Study plan
 
The clinical cases of dogs presented at VCC during the study period were screened for renal disorders by employing detailed physical examination, haemato-biochemistry, blood smear examination, urinalysis, radiography and ultrasonography.  The confirmed cases of renal failure were further analyzed to assess epidemiological parameters i.e. Age (0-2, 2-4, 4-6, 6-8, 8-10 and >10 years), Gender (Male/Female), Breed, Month (January to December) and Season (summer, monsoon and winter). The data are presented in either number or percentage. 
 
Diagnosis of renal disorders
 
Clinical examination
 
All the animals underwent a clinical examination, gathering comprehensive information about the general condition, clinical signs and vital parameters, i.e. rectal temperature, heart rate, respiration rate, the colour of the conjunctival mucus membrane, size of lymph nodes, capillary refilling time and dehydration percentage, were recorded during the examination. A physical examination was carried out by palpation for assessment of abnormities related to the urinary system, viz. abdominal pain, enlargement of the urinary bladder, swelling over the prepusal region, tissue growth over the genital organ and micturition pattern (oliguria, straguria, hematuria or hemoglobinuria, anuria and dribbling of urine/urinary incontinence).
 
Sample collection
 
Blood samples were collected in a sterile anticoagulant vial containing ethylene diamine tetra acetic acid (K3EDTA) and clot activator vial from clinical cases as well as healthy animals were subjected to analysis to compare the alterations in affected dogs. The collection of urine samples from dogs was carried out as per the standard method described by Sink and Weinstein (2012) depending on the clinical manifestation of renal dysfunction by either of these procedures: Collection of freshly voided urine sample or Collection of the urine sample by gentle compression of the urinary bladder or collection of urine by use of a urinary catheter in cases with urinary incontinence, obstruction or dribbling.
 
Sample analysis
 
A complete hemtobiochemical analysis was carried out by automated machines. In addition a physical and semi-quantitative urinalysis was performed by dip-stick method followed by analysis by URISCAN machine.
 
Nephrosonography
 
EXAGO B-mode ultrasound machine was used to perform a nephrosonogram. A convex probe with 3.5 MHz, 5 MHz and 7.5 MHz frequencies was used for large, medium and small dogs, respectively. The echogenicity of the identifiable lesion was classified on the basis of grayscale 2-dimensional images, subjectively. A standard procedure was used for ultrasonography includes:  Clipping of hair on the entire abdomen, positioned either on its side or its back and a generous amount of coupling gel was applied to ensure good contact. Standard mid-sagittal and mid-transverse planes were obtained as per the established protocol. The grayscale 2-dimensional images were used to identify lesions and the echogenicity of these lesions was classified as usual, increased (hyperechoic), decreased (hypoechoic), or absent (anechoic) compared to the regular echo pattern for canine kidneys (Walter et al., 1987).

In the present investigation, 2850 dogs presented at the Veterinary Clinical Complex were screened for renal disorders from September 2022 to August 2023. Out of 2850 dogs, 170 dogs were suffering from renal disorders. 170 dogs, various clinical abnormalities were observed and the most common signs were weakness/apathy, vomiting, oliguria to polyuria, dehydration and melena in 118 dogs. Subsequently, other signs like ataxia, roupy salivation, ascites and arrhythmia was evident. In addition, some dogs reported to be having petechiae, recumbency, prostration, epilepsy and pleural effusions. The vital parameters like rectal temperature (103.1±0.49 °F) Heart rate (138.7±2.61 beats/min), respiration rate (34.44±2.1 breaths/min) and capillary refilling time (1.2±0.23 sec) in affected animals showed elevation in values but was in normal reference range.
 
Age wise distribution
 
Age wise distribution is depicted in Table 1. The overall incidence of renal disorders was 5.96 per cent. Only 1 dog (0.27%) was having renal disorders in the age group of 0-2 year while 28 dogs (5.31%) were having renal disorder in the age group of >10 years. An increase in the incidence of renal disorder was noted with advancement of age as 28 dogs (7.35%), 37 (8.42%) and 56 (9.62%) in the age groups of 2-4, 4-6 and 6-8 years, respectively. The higher incidence of renal disorders was observed in dogs of age group 6-8 years followed by 8-10 years.
 

       
These findings was in corroborate with Karunanithy et al., (2019) who reported higher incidence rate of kidney diseases in the 6-8 years age group. Sahu et al., (2021) recorded the highest prevalence of renal disorders in dogs aged 5-10 years (54.29%) followed by dogs belonging 18 months to 5 years (24.29%) and belonging more than 10 years of age (15.71%).
       
The incidence of renal disorders is increased with the advancement of age (Nabi et al., 2018; Meena et al., 2022; Ahmed et al., 2023; Chand et al., 2024) while Mshelbwala et al., (2016) opinioned that senile age could be a precipitating factor in renal failure. As age increases, their kidney function may decline due to reduced blood flow and a depletion of nephrons. Additionally, the resorption mechanisms within the nephrons may become compromised. These factors can heighten the risk of developing renal dysfunction.
 
Gender-wise distribution
 
Table 2 suggest that male dogs had a slightly higher incidence of the health condition compared to female dogs (6.61% vs. 5.17%). The present observation is lined well with findings of (Tufani et al., 2015; Katoch et al., 2017; Sahu et al., 2021; Meena et al., 2022; Ahmed et al., 2023 and Chand et al., 2024). 
 

       
However, it differs from the findings of and Bhojne et al., (2016) and Bouillon et al., (2018) who reported a higher incidence of females than males in similar cases. The reason could be environmental variables, rather than hormonal factors, may have contributed to the predisposition to renal disorders Mshelbwala et al., (2016) while Kandula and Karlapudi (2014) concluded higher incidence in female dogs might be due to various unhygienic management practices during the puerperal stage that may lead to genital infection and may progress as urogenital complaints. Understanding gender-specific risks can be crucial for veterinarians and pet owners. It may influence screening protocols, treatment strategies and overall health management for dogs. However, further analysis and consideration of factors such as population demographics and potential risk factors should be consider to enhance the understanding of these findings.
 
Breed-wise distribution
 
The study found that the Labrador retriever breed has one of the highest incidence rates of renal disorders, with 9.68% of the 558 presented dogs being affected (Table 3). German Shepherds had a slightly lower incidence rate of 7.24%, while smaller breeds like Pomeranians and Pugs had lower incidence rates of 3.64% and 3.92%, respectively. Dalmatians and Lhasa Apsos had no affected dogs in the data set, indicating their remarkable health resilience. This finding was no longer differ from other researcher who found higher incidence in Labrador retriever breed of dog. i.e. (Tufani et al., 2015; Katoch et al., 2017; Sahu et al., 2021; Ahmed et al., 2023 and Chand et al., 2024).
 
 
       
Due to friendly and gentle temperament, obedience, agility, adaptable to different living environments, Labradors are making them great family pets and companions. In the present investigation, the higher incidence could be due to higher number of dogs presented during study period. This data can be useful for veterinarians, researchers and breeders in managing and addressing health concerns in different breeds and understanding the prevalence of certain conditions or diseases within specific dog breeds.
 
Month-wise distribution
 
The data of Table 4 indicates variability in monthly incidence rates, with peaks observed in October (10.0%), September (9.1%) and August (8.5%). Conversely, lower incidence rates were noted in June (3.7%), February (4.1%) and December (4.2%). Currently, there is a dearth of information on the monthly incidence of renal disorders among canines. Hence, this could be first ever study to elucidating month wise incidence. The fluctuations in monthly incidence rates suggest potential seasonal, environmental, or demographic influences on the prevalence of renal disorders in dogs. Factors such as climate changes, exposure to allergens and variations in dog population dynamics may contribute to these patterns.
 

 
Season-wise distribution
 
Seasonal variations in disease incidence have been documented in various species, including dogs. However, limited research has focused on how seasonal changes impact the prevalence of renal disorders among dogs. This study aims to fill this gap by analyzing data collected over twelve months, categorized into three distinct seasons, to elucidate seasonal patterns in renal disorders among dogs. The data indicate a clear seasonal variation in renal disorders among dogs (Table 5). The Monsoon season shows the highest incidence rate at 7.61%, followed by summer at 5.64% and winter at 5.03%. These findings suggest a potential influence of seasonal factors on the prevalence of renal disorders across different breeds. The higher incidence rates observed during the Monsoon season may be attributed to environmental factors such as increased humidity, changes in allergen exposure, or seasonal variations in infectious agents.
 

 
Renal disorders
 
The data reveal that nephritis and renal failure (AKI/CKD) are the most prevalent renal disorders among the studied dogs, each accounting for 35.88% of cases. Cystitis and urolithiasis also show notable percentages at 10% and 6.47%, respectively. Other renal disorders such as UTI, urethritis, polycystic kidney disease, hydronephrosis and tumors have lower but still significant prevalence rates within the sample population (Table 6).
 

 
The present observation were in agreemnent with Vijay Kumar et al., (2011) who reported that Nephritis, urolithiasis, end stage kidney and hydronephrosis were the more common renal disorders among dogs. Whereas, Ji-Young et al., (2010), reported that urolithiasis (24.30%) and nephritis (22.9%) were the common renal disorders in dogs. Present findings were opposite to Katoch et al., (2017) who reported 4.74 per cent (108/2277) renal disorders while Chaitanya et al., (2020) noted overall occurrence of renal affection was 3.48% (318/9347). Of 318 affected dogs, 58 (18.24%) suffered with acute kidney injury, while 260 (81.76%) were of chronic kidney disease. Gupta et al., (2021) recorded 14 dogs with signs of renal failure while 18 were of urinary obstruction. Kumar et al., (2022) studied 576 geriatric dogs and noted 81 dogs had signs suggestive of renal diseases. Amongst, 52 cases diagnosed for different lower urinary tract disorders viz., cystitis (n=22), cystic calculi (n=13), prostate infection (n=8), transitional cell carcinoma (n=5) and both calculi with cystitis (n=4). This might be due to increased urbanization and environmental pollution, unscientific feeding and indiscriminate use of therapeutic agents (Katoch et al., 2017). The variations in the occurrence could be due to several extrinsic factors like variations in geographical, environmental and manage mental practices or differences in sample size. The high prevalence of nephritis and renal failure underscores the importance of early detection, proper management and targeted interventions for these conditions in dogs. Factors contributing to the incidence of these disorders, such as breed predispositions, environmental influences and underlying health conditions, merit further investigation.

Canine renal disorders, a medical condition affecting the kidneys of dogs, are a significant concern that requires attention from pet owners and veterinary professionals. Early detection and intervention can mitigate these disorders’ adverse effects and improve the affected dogs’ quality of life. Therefore, it is critical to have a comprehensive understanding of the signs, symptoms and risk factors associated with such disorders. Pet owners should be vigilant in monitoring their dogs for any signs of renal disorders, such as changes in urination patterns, weight loss, or loss of appetite. Veterinary professionals can provide valuable guidance in managing these conditions through appropriate diagnostic testing, treatment and ongoing monitoring. By working together, pet owners and veterinary professionals can ensure the best possible outcomes for canine patients with renal disorders.

The authors are highly thankful to the Director of Research and Dean of Kamdhenu University, Gandhinagar for providing funds and necessary facilities in carrying out the present research work.

The authors declare no conflicts of interest.