Molecular detection of Leptospira spp. from canine kidney tissues and its association with renal lesions

The study aimed to detect the prevalence of Leptospira spp. in kidney tissues collected during necropsy and to establish its association with renal lesions in dogs of Mumbai region.

Kidney tissues from 40 dogs were collected during necropsy after gross examination and then fixed in neutral buffered formalin and Bouin's fluid for histopathology and histochemistry, respectively. Kidney tissues were also collected for the detection of Leptospira spp. by polymerase chain reaction (PCR) in a sterile container and stored at -80°C until further processing.

Of 40 cases studied, 13 (32.5%) cases showed lesions of nephritis of varying histotype and severity. Glomerulonephritis was reported as the most common type of nephritis in 9 (69.23%) cases, and interstitial nephritis was recorded in 4 (30.76%) cases. Chronic and acute interstitial nephritis was observed in two cases each. Renal failure as a cause of death was found in 7 (17.5%) dogs. Of a total of 40 cases, 9 were found positive for pathogenic Leptospira spp. genome by PCR. However, of nine PCR-positive cases, only four cases showed lesions in kidneys as glomerulonephritis and interstitial nephritis in two cases each. The rest five cases positive for Leptospira spp. by PCR did not show any appreciable lesions in the kidneys.

Leptospiral DNA was detected in 9 (22.5%) cases by PCR. Of these nine cases, only four cases showed renal lesions. Other five cases which were positive for Leptospira spp. by PCR did not show any appreciable gross and microscopic lesions in the kidneys which might be carriers for Leptospira spp. Considering variable reports on types of nephritis in Leptospira spp. infection and also the prevalence of non-pathogenic Leptospira spp., it is important to conduct an extensive study on the prevalence of Leptospira spp. and its association with renal lesions involving batteries of tests.