Clinical and pathological effects of Dirofilaria repens and Dirofilaria immitis in a dog with a natural co-infection

- A case of Dirofilaria immitis and D. repens natural co-infection is presented.
- Ectopic localizations of D. repens adults are reported.
- The pathological role of microfilariae is discussed.

Canine dirofilarioses are mosquito-borne zoonotic diseases with a continuous expansion of their geographical distribution, as a consequence of different climatic and ecological factors. Dirofilaria immitis, the aetiological agent of heartworm disease, has gained a major veterinary interest, mainly due to its severe clinical implication. In the last decades, D. repens, despite of being regarded as a less pathogenic species, regained attention due to its recognized zoonotic potential. Romania has been traditionally regarded as a non-endemic country, but recent epidemiological surveys are highlighting the presence of both D. repens and D. immitis. The present case report describes the clinical and pathological features of a natural co-infection with D. repens and D. immitis in 5 year old male Boxer from north-western Romania. Based on clinical and laboratory investigations, a diagnosis of kidney failure and chronical cystitis was established. The parasites were identified by morphology and confirmed by PCR and sequencing. To the best of our knowledge this is the first worldwide report of the ectopic presence of D. repens adults in the pelvic cavity and mesentery by natural infection and first report of the ocular localization of this parasite for Romania. The clinical and paraclinical findings suggest the implication of D. repens microfilariae in the aetiology of histopathological lesions. Further investigations are needed in order to establish the actual pathogenic potential of D. repens, a frequently neglected parasite.