First detection of Onchocerca lupi infection in dogs in southern Spain

Background: Onchocerca lupi causes ocular pathology of varying severity in dogs from south-western United States, western Europe and northern Asia. This filarioid has also been recognized as a zoonotic agent in Tunisia, Turkey, Iran and the USA, though the information about the biology and epidemiology of this infection is largely unknown. In Europe, O. lupi has been reported in dogs from Germany, Greece, Hungary, Portugal and Romania and in a cat from Portugal. The present study was designed to establish the occurrence of O. lupi in dogs in southwestern Spain. In the present study a total of 104 dogs of different breed, sex, and age living in a shelter in Huelva (SW Spain) were examined. Skin snip samples were collected using a disposable scalpel in the forehead and inter-scapular regions and stored as aliquots in saline solution (0.5 ml) before light microscopy observation of individual sediments (20 mu l) and molecular examination. Results: Of the 104 dogs examined, 5 (4.8 %) were skin snip-positive for O. lupi: two by microscopy and three by PCR. One of the O. lupi infected dogs showed neurological signs but ocular ultrasonography and/or MRI detected no abnormalities. Conclusions: This first report of O. lupi infection in dogs in southern Spain expands the range of geographical distribution of this parasite and sounds an alarm bell for practitioners and physicians working in that area.