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| *Oocyst contains 2 sporocysts with 4 sporozoites | | *Oocyst contains 2 sporocysts with 4 sporozoites |
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| + | *Route of transmission not fully understood |
| + | |
| + | *Often misdiagnosed as ''Toxoplasma gondii'' |
| + | **''Sarcocystis'' cysts have thicker walls |
| + | |
| + | *Infection diagnosed by IFAT, ELISA or PCR |
| + | **Identification of lesions and organisms in tissue using immunohistochemical staining |
| + | **Eliminate other causes of abortion first |
| + | |
| + | '''Life cycle''' |
| *Life cycle similar to ''Toxoplasma gondii'' | | *Life cycle similar to ''Toxoplasma gondii'' |
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| **Intermediate host for ''N.hughesi'' is the horse, but the definitive host is unknown | | **Intermediate host for ''N.hughesi'' is the horse, but the definitive host is unknown |
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− | *Route of transmission not fully understood | + | *Final host |
| + | **Dogs pass oocysts |
| + | **Role not fully understood in pathogenesis |
| + | **5 day prepatent period |
| + | **Other wild canids may also act as final definitive hosts |
| + | |
| + | *Intermediate host |
| + | **Mostly cattle |
| + | **Natural infection has been documented in other herbivores |
| + | |
| + | *Transmission |
| + | **Transplacental infection occurs in all intermediate hosts and in the canine final host |
| + | ***Transplacental can occur in '''successive pregnancies''' |
| + | **In cattle, vertical transmission occurs |
| + | ***Post-natal infection occurs but is less common |
| + | |
| + | '''Pathogenesis''' |
| + | *Dogs |
| + | **Occurs mainly in puppies |
| + | **Causes ascending paralysis, especially of hind limbs, with muscle wasting |
| + | **Causes sudden collapse due to myocarditis |
| + | **More than puppy in a litter may be affected, although this may not occur simultaneously |
| + | **Successive litters affected |
| + | |
| + | *Cattle |
| + | **Commenest cause of infectious abortion in dairy cattle |
| + | **Congenitally infected calves can have encephalomyelitis and paresis |
| + | **Abortion usually occurs between 5-7 months of gestation but can occur as early as 3 months |
| + | **No other clinical signs in the cow |
| + | **Repeat abortions possible in same cow (persistently infected) |
| + | |
| + | *Horses |
| + | **Myeloencephalitis |
| + | **Transplacental infection occurs |
| + | **Disease only diagnosed in USA |
| + | |
| + | '''Prevention and Control''' |