A case of intraocular dirofilaria in a dog: alarm bell for human beings?

Purpose The genus Dirofilaria includes various species, in particular immitis and repens, that are natural parasites of dogs and other domestic and wild mammals. From those natural hosts microfilariae circulating in blood may accidentally be transmitted by mosquitoes to man. These microfilariae can be localized in the human beings' periorbital or subconjunctival tissues or in the intraocular region. This case report observed an increase of the ocular filariasis in dogs and it aims to put emphasis on the possible transmission of this parasite from animals to the human eye. Methods A 2-year-old male, mixed breed living in the North of Italy, in the Emilia Romagna area, was presented to the author having pain to the right eye. Ocular esamination showed miosis, corneal edema and low intraocular pressure. Slit lamp examination revealed a lively motile worm in the anterior chamber. Results It was not possible both to remove the parasite and to identify its species. At the same time no parasite was identified in the peripherial blood. Conclusion The rise of weather temperatures of these last years caused an increase in the occurrence of “tropical disease”. This particuar case shows many similarities to the human parasite because the dog had no microfilariae in the blood. Many studies pointed out a remarkable incidence of microfilariae in the dogs' eyes living in the Mediterrenean area; this remark must be taken into serious consideration because it can be considered as an emerging zoonosis and as an alarm bell for human beings.