It is debated as to whether heartworm can cause renal disease, as the evidence as yet is indirect. There has been an association noted between heartworm infection and renal disease, and the renal problems have been alleviated following heartworm therapy.
Most infected dogs have no renal damage.
The immune response of the infected individual may also affect the probability of renal disease. There are three proposed mechanisms as to how the renal disease may progress. The disease may be immune complex mediated, causing damage to the glomerular basement membrane. Fluorescent antibody tests have demonstrated Ig deposition on the basement membrane. Secondly, microfialria induced trauma to the glomerular epithelium may cause glomerulosclerosis.