Neosporosis
Neospora caninum is a coccidian parasite related to Toxoplasma gondii. The dog is the definitive host, with sexual stages in the gut resulting in oocysts shed in faeces.
Cattle (an intermediate host species) are infected by ingesting feed contaminated by sporulated N caninum oocysts shed by dogs or by infected cattle tissues (eg infected foetal membranes), or are infected transplacentally.
The asexual proliferative stages of Neospora caninum (including tissue cysts), cause:
- Abortion in cattle (world-wide, including coastal NSW) and congenital neonatal neurological disease in cattle (rarely). Neospora abortion is reported in deer (rarely).
- Neurological disease in the dog (rarely)
Diagnosis
Cattle
History, clinical signs (abortion), histopathology, serology.
Distinctive histological changes are seen in brain (necrogranulomatous encephalitis) and myocardium (non-suppurative myocarditis).
Dog
Clinical signs (neurological disease), histopathology, serology.
Specimens required
Cattle
Aborted foetuses
- Specimens as required for diagnosis of Abortion in cattle, particularly:
- Serous foetal body fluid (pericardial, thoracic or peritoneal) or heart blood for serology
- Brain and myocardium (including from autolyzed foetuses) formalin-fixed for histopathology
Cows
- 10 ml of clotted blood in vacuum tube for serology. A group of aborted and non-aborted animal should be tested. In view of the widespread prevalence of subclinical neosporosis in cattle in coastal NSW areas, seropositivity in an aborted cow does not confirm Neospora abortion.
Dogs
- Spinal cord and brain and other tissue formalin-fixed for histopathology.
- Clotted blood in vacuum tube for serology.