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