Marked subcutaneous mast cell and eosinophilic infiltration associated with the presence of multiple Dirofilaria repens microfilariae in 4 dogs.

Dirofilaria repens is a parasitic nematode in the subcutaneous tissue of carnivores, including dogs and cats, transmitted by mosquitoes. Human beings may be accidental hosts. Infection of a dog with D repens was first reported in Palestine in 1934, and 2 additional cases were reported in dogs in Israel to date.