Lesions and distribution of Neospora caninum in tissues of naturally infected female goats

• This is the first study of N. caninum distribution in adult female goat tissues.
• This is the first study that analyzed several tissues to demonstrate the NC distribution.
• In the CNS the highest positive results for NC was in spinal cord cervical segment.
• Cleidooccipital, brachial tríceps and semimembranaceous were the most affected muscles.

Histopathology, immunohistochemistry (IHC) and molecular biology methods were used to evaluate the lesions and the distribution of Neospora caninum in the tissues of eight female non-pregnant goats, naturally infected with N. caninum. The goats transmitted the parasite to their offspring in previous pregnancies. Histopathological examination showed a mild lymphoplasmacytic inflammatory infiltrate in skeletal muscles (10/168 muscles; 1.68%) and myocardium in two goats. Moderate to severe lymphoplasmacytic perivascular cuffs were the most significant lesion in the nervous system and were observed in 62.5% of the goats. Mild to moderate gliosis also affected 37.5% of them. Parasitic structures were not found in the tissues by histopathology and IHC labeling for N. caninum Polymerase chain reaction (PCR) analysis of 359 tissue samples showed 133 (37%) positive samples. The highest percentage of positive results was found in the nervous system (28/63; 44.4%) and skeletal muscle (72/168; 42.8%). Statistical analysis of the PCR results did not show parasitic preference for any particular muscle group (head, hindlimbs, neck, thoracoabdominal or forelimb muscles) or region of the nervous system. Yet, the highest percentage of PCR-positive samples was from the cleido-occipital, brachial triceps and semimembranosus muscles and the cervical segment of the spinal cord (62.5% each).These data suggest that PCR diagnosis of N. caninum infection should include analysis of these tissues. This is the first report of N. caninum distribution in adult female goat tissues.