Microalbuminuria (MAU) is associated with underlying renal and systemic diseases in dogs. Glomerular disease and proteinuria is common in dogs naturally or experimentally infected with Dirofilaria immitis. The prevalence of MAU in dogs with experimentally infected heartworm disease is higher than in healthy animals. Dirofilaria repens is the causative agent of subcutaneous canine dirofilariasis and is considered an emerging zoonosis in many parts of Europe. Dirofilaria repens infection is usually associated with no or only minor clinical signs in dogs. It is not known whether D. repens is capable of producing similar glomerular lesions and proteinuria to those caused by heartworm infection.

The purpose of this study was to determine the prevalence of MAU (urinary albumin to creatinine ratio, UAC >0,03) and proteinuria (urinary protein to creatinine ratio, UPC >0,5) in dogs naturally infected with D. repens.

Blood and urine samples were taken from 70 clinically healthy beagles kept in two closed colonies with similar housing and feeding conditions. Extensive laboratory workup was used to reveal any underlying disease and to distinguish D. repens infection from occult heartworm disease (including modified Knott test, two different Ag-ELISA tests and Dirofilaria species specific real time PCR). Urine was obtained by cystocentesis and albumin was measured with a formerly validated commercial human immunoturbidimetric method. Exclusion criteria were severe laboratory alterations, a positive D. immitis test or positive urine culture. Some older, otherwise eligible, D. repens-infected dogs also had to be excluded, as there were no older animals without infection to age match the two groups.

After all the exclusions, there remained 29 D. repens-infected and 27 non-infected beagles. There were no statistically significant differences between the two groups in respect of their age, weight and sex ratio. There were significantly more dogs with MAU in the D. repens-infected group compared to the non-infected beagles (28% vs. 4%, p=0,0150). There were also more proteinuric dogs in the infected group (24% vs. 7%), but it did not yield a significant difference (p=0,0885).

Our study showed that the prevalence of MAU in dogs infected with D. repens is higher than that observed in other non-infected dogs kept in the same conditions. Further studies are needed to determine whether dogs infected with D. repens and MAU will progress to develop overt proteinuria and renal failure.

Disclosures

Disclosures to report
The research was partly supported by Bayer Hungary.