NEOSPORA CANINUM OOCYST SHEDDING IN A NATURALLY INFECTED DOG

Although the seroprevalence of Neospora caninum infection in dogs can be relatively high, there are few reports of dogs naturally shedding N. caninum oocysts and the prevalence of Neospora excretion in faeces is about 0.03% in Europe. A mixed-breed male household dog of about 8 years in age living in the district of Pisa was referred for dysorexia, weakness and general lymph node enlargement. Clinical pathology evidenced mild normocytic and normochromic anaemia, thrombocytopenia and hypoproteinemia with hypoalbuminemia. Serology for Leishmania, Ehrlichia canis and Anaplasma phagocytophilum was negative. From lymph node and bone marrow analysis, T cell lymphoma, high grade, pleomorphic type, clinical stage V, was diagnosed. The dog was treated with a chemotherapy induction protocol with vincristine (0.75mg/m2 IV once a week), cyclophosphamide (50mg/m2 orally 3–4 days/week), and prednisone (40mg/m2 orally daily for the first week, then tapered to 5 mg/m2 orally daily in the further weeks) for 8 weeks. A faecal sample analysed by flotation test by using a low density solution 7 days after the beginning of the treatment, revealed the presence of N. caninum-like unsporulated oocysts of about 10-11 um in diameter. An aliquot of the same faecal sample analysed by PCR with species-specific primer pairs Np6+/Np21+ was positive for N. caninum DNA, while serology for N. caninum performed a month later by IFAT, was positive with a titer of 1:320. Naturally occurring systemic illness or iatrogenic immunosuppression may predispose dogs to proliferation of the parasite. The dog described was receiving chemo-immunosuppressive treatment for T cell lymphoma. For these reasons it is not possible to suppose whether emission of Neospora oocysts in this dog was caused by reactivation of a latent infection or by a recently acquired infection.