Neospora caninum: the First Demonstration of the Enteroepithelial Stages in the Intestines of a Naturally Infected Dog.

A 1.5-month-old Kangal breed puppy from a dairy cattle farm died after showing severe diarrhoea and incoordination. Necropsy examination revealed multifocal pulmonary consolidation and necrosis and fibrinohaemorrhagic enteritis. Microscopically, there was necrotic and purulent bronchopneumonia, myocarditis and non-purulent encephalitis. In the jejunum and ileum there was villous atrophy and crypt hyperplasia with oocyst-like and schizont-like structures in the epithelia. Immunohistochemically, Neospora caninum antigen was detected in association with the intestinal protozoal structures, degenerative neurons and areas of necrosis in the lungs and heart. Polymerase chain reaction confirmed that the organism was N. caninum and not Toxoplasma gondii. The seroprevalence for N. caninum was 74.2% (49/66 animals) for the cattle and 57.1% (4/7 animals) for dogs on this farm. This report documents fatal systemic neosporosis and enteroepithelial stages of N. caninum in a naturally infected puppy. To the authors' knowledge, this is the first definition of intestinal neosporosis in a naturally infected dog as well as the first evidence of fatal canine neosporosis in Turkey.

Astrocytes, microglia/macrophages, and neurons expressing Toll-like receptor 11 contribute to innate immunity against encephalitic Toxoplasma gondii infection.

Toll-like receptor 11 (TLR11) is a specific receptor for Toxoplasma gondii and uropathogenic Escherichia coli and has recently been identified in the mouse brain. In the present study, TLR11 gene expression was measured in the mouse brain by Real-time quantitative polymerase chain reaction (RT-PCR). Furthermore, the TLR11 protein expression profile was evaluated in neuroglia and neurons throughout the encephalitic period (10, 20, and 30days after inoculation) in mice with experimentally induced T. gondii infection. In the brains of experimental (n=21) and control (n=7) mice, TLR11, glial fibrillary acidic protein (GFAP), cd11b, NeuN, TLR11/GFAP+, TLR11/cd11b+, and TLR11/NeuN+ cells were investigated using either indirect single- or double-labeling immunoperoxidase staining. The results indicated that TLR11 gene expression increased during chronic toxoplasmic encephalitis, and there was a variable degree of TLR11 immunopositivity among cd11b+, GFAP+, and NeuN+ cells in the brain. On the tenth day of infection, there was a significant increase in TLR11 protein and gene expression, which remained stable during the later stages of infection. In this experimental model, TLR11 expression was induced in astrocytes, neurons, and microglia/macrophages during the immune response to T. gondii infection.