Microfilariosis in Dogs ? An Emerging Cause for Renal Failure

" ABSTRACT Filariasis is a disease of great public health importance in the country. It can remain asymptomatic for years. Since Kerala is an endemic focus of brugian filariosis, we have to consider the role of natural filarial infections as one of the possible cause for increasing incidence of renal failure in human beings and dogs.The present study was carried out to elucidate the possible role of microfilariae in renal diseases in dogs. Hundred dogs above 6 months of age presented to Veterinary college hospital with clinical signs suggestive of microfilariosis were utilised for the study. Animals screened positive for microfilaria by wet film examination were subjected to detailed study and treatment trials. Serum samples were collected from all the animals, blood urea nitrogen (BUN) and creatinine were analysed and compared with healthy controls. Urine samples of microfilaraemic and six healthy controls were analysed for specific gravity , bile pigments and protein ,urine protein creatinine ratio, γ glutamyl transferase, alkaline phosphatase (ALP) and N-Acetyl-β-D-Glucosaminidase (NAG). Ultrasonographic evaluation of kidneys of a few affected animals revealed hyperechoic areas in medullary region and renal pelvis with corresponding reduction in corticomedullary delineation indicating advanced renal damage. Results of biochemical and urinalysis revealed elevated levels of BUN, creatinine, urine protein creatinine ratio, NAG, ALP, proteinuria with low specific gravity. Two animals died during the course of treatment were subjected to postmortem examination and lesions indicating chronic interstitial nephritis were observed. Results of ultrasonographic evaluation, biochemical and urinalysis and histopathological evaluation were highly correlated to suggest an impending renal insult. Nephrotoxic changes could be reversed if treatment instituted at an early stage. This renal pathology in canine microfilariosis suggested the involvement of toxic and immunological effects of filarial parasites in the pathogenesis of the disease. "