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Tissue cyst-forming coccidia (view source)
Revision as of 18:50, 18 November 2008
, 18:50, 18 November 2008→Sarcocystis
*Oocysts are sporulated when passed
*Oocysts are sporulated when passed
**Difficult to find on faecal examination as the sporocysts are few in number and small
**Difficult to find on faecal examination as the sporocysts are few in number and small
*Ingestion of sporocyst by intermediate host
**2 phases of rapid asexual reproduction in vascular endothelial cells
**Slow multiplication of bradyzoites in muscle tissue
**Sarcocyst forms with bradyzoites inside, surrounded by a cyst wall and divided into compartments
'''Epidemiology'''
*Final hosts are carnivores and omnivores
*Intermediate hosts are herbivores and omnivores
*Humans are the final host for some species and the intermediate hosts for others
**Final host for species infecting cattle and pigs
*Dogs are final hosts for species infecting cattle, sheep, goats, pigs and horses
*Cats are final hosts for species infecting cattle, sheep and pigs
'''Pathogenesis'''
'''Pathogenesis'''
*Widespread infection but mostly asymptomatic
*Cause meat inspection losses
*Cause meat inspection losses
*''Sarcocystis'' in [[Muscles Inflammatory - Pathology#Protozoa|myositis]]
*''Sarcocystis'' in [[Muscles Inflammatory - Pathology#Protozoa|myositis]]
*Experimental infections cause severe, acute pyrrhexic disease when the organism multiplies in the vascular endothelium
*Can cause chronic wasting disease in cattle and horses
**Causes abortion and post-natal disease in sheep
*Equine protozoal myeloencephalitis
**Necrotising encephalomyelitis affecting the grey and white matter of the CNS
**Caused by ''S.neurona''
**Opossum thought to be the definitive host
**Horses thought to be accidental hosts
**Natural intermediate hosts currently unknown
**Western Blotting shows 50% of horses in the USA are seropositive
**Risk factors poorly understood
**Causes spinal cord dysfunction
***Ataxia and paralysis
==Neospora==
==Neospora==