Frequency and Type of Renal Lesions in Dogs Naturally Infected with Leptospira Species

Authors

  • A. Ortega-Pacheco,

    1. Departamento de Medicina Interna y Cirugía, Facultad de Medicina Veterinaria y Zootecnia, Universidad Autónoma de Yucatán, Mérida, Yucatán, México
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  • R. F. Colin-Flores,

    1. Departamento de Medicina Interna y Cirugía, Facultad de Medicina Veterinaria y Zootecnia, Universidad Autónoma de Yucatán, Mérida, Yucatán, México
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  • E. Gutiérrez-Blanco,

    1. Departamento de Medicina Interna y Cirugía, Facultad de Medicina Veterinaria y Zootecnia, Universidad Autónoma de Yucatán, Mérida, Yucatán, México
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  • M. Jiménez-Coello

    1. Laboratorio de Biología Celular, Departamento de Biomedicina de Enfermedades Infecciosas y Parasitarias, Centro de Investigaciones Regionales “Dr. Hideyo Noguchi” Unidad Biomédicà, Universidad Autónoma de Yucatán, Mérida, Yucatán, México
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Address for correspondence: Matilde Jiménez-Coello, DVM., CIR ‘Dr. Hideyo Noguchi’, Laboratorio de Biología Celular, Departamento de Biomedicina de Enfermedades Infecciosas y Parasitarias, Universidad Autónoma de Yucatán, Av. Itzaes No. 490 x C. 59 CP 97000, Mérida Yucatán, México. Voice: +52 999 9245755; fax: +52 999 9245755. mjcoello@uady.mx

Abstract

The aim of this study was to determine the frequency and type of renal lesions associated with positive titers against Leptospira sp. in a stray dog population. Three hundred fifty pairs of kidneys and an equal number of serum samples were collected from dogs captured by the dog pound of Merida, Yucatan, Mexico. Euthanasia of dogs was performed following the regulations of the Official Mexican Health Ministry (NOM-033-ZOO-1995). Serum samples were evaluated with the microscopic agglutination test, and tissue samples were processed and fixed in paraffin. After staining with hematoxylin and eosin, the frequency of renal lesions was determined and classified. As an additional evaluation, samples with interstitial nephritis were stained by the Warthin–Starry method in order to observe the presence of spirochete forms that could be morphologically compatible with Leptospira spp. We found that 98% of cases presented at least one type of lesion. The main histological lesions found were mesangial proliferative glomerulonephritis (MPGN) in 63.7% (n= 223), mesangial proliferative glomerulonephritis and interstitial nephritis (MPGN+IN) in 34% (n= 119), nephrosclerosis in 0.57% (n= 2), mesangial glomerulonephritis in 0.28% (n= 1), and interstitial nephritis (IN) in 0.28% (n= 1). Thirty-four percent (n= 122) of the dogs were seropositive to Leptospira sp., mainly against serovar canicola. Among dogs with IN (alone or associated with MPGN) (n= 120), 49.1% were seropositive to Leptospira sp., but only 17% of them showed spirochete forms compatible with the bacteria. A statistical association between seropositive dogs and the presence of MPGN+IN was determined (P < 0.0001; odds ratio 2.7, confidence interval 1.7–4.5). We concluded that the frequency of renal lesions found in this study is high and L. canicola is probably the most common circulating serovar in dogs from this area. Dogs that have been in contact with Leptospira spp. have a higher risk of developing renal lesions of the type MPGN+IN.

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