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}}
 
<br>
 
<br>
 +
 +
==Neospora==
 +
*2 main species
 +
**''Neospora caninum'' in the dog
 +
**''Neospora hughesi'' in the horse
 +
 +
*Sporulated oocysts measuring just 10μm
 +
 +
*Oocyst contains 2 sporocysts with 4 sporozoites
 +
 +
*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''
 +
 +
*Limited range of warm-blooded intermediate hosts
 +
**Asexual reproduction occurs in intermediate host forming tissue cysts
 +
 +
*Host range of sexual stage is unknown for ''N.caninum''
 +
**Intermediate host for ''N.hughesi'' is the horse, but the definitive host is unknown
 +
 +
*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
 +
 +
*''Neospora caninum'' in [[Muscles Inflammatory - Pathology#Protozoa|myositis]]
 +
 +
'''Prevention and Control'''
 +
*Do not allow dogs access to calving cows, placental membranes and aborted or dead calves
 +
 +
*Do not allow dogs to defecate in cattle feeding areas
 +
 +
*Identify and cull seropositive cattle, or do not breed from them or their progeny
 +
 +
*Select seronegative cattle for breeding
 +
 +
*Vaccinate
 +
**Only in the USA
 +
**Neoguard or Intervet
 +
**Killed protozoal vaccine for healthy, preganant cows
 +
**Dosed in first 3 weeks of pregnancy and then every 3-4 weeks during gestation
 +
**Revaccination with 2 doses during each subsequent pregnancy
 +
 +
==Sarcocystis==
 +
[[Image:Sarcocystis Life Cycle.jpg|thumb|right|150px|''Sarcocytis'' Life Cycle Diagram - Dennis Jacobs & Mark Fox RVC]]
 +
[[Image:Sarcocystic.jpg|thumb|right|150px|''Sarcocytis'' - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona]]
 +
*Most infections are asymptomatic
 +
 +
*Heavy infections are causes of chronic wasting in large animals, hide sondemnation and downgrading of carcasses
 +
 +
*''Sarcocystis'' should be differentiated from other tissue-cyst forming coccidia
 +
 +
*There are many species of ''Sarcocystis'' which differ in size from microscopic to several centimetres in length
 +
**''S.neurona'' is an important equine pathogen in the USA
 +
 +
*Infective cyst in the intermediate host is called a '''sarcocyst'''
 +
 +
'''Life Cycle'''
 +
*Individual life cycles incompletely misunderstood
 +
 +
*Indirect life cycle
 +
 +
*Life cycle alternates between the final and the obligatory intermediate host
 +
 +
*Only '''one''' final and '''one''' intermediate host
 +
 +
*Sporulated oocyst has 2 sporocysts containing 4 sporozoites
 +
**Naked oocyst usually seen in faeces as the oocyst wall is very delicate
 +
**Oocyst measures 15μm in length
 +
 +
*No schizogony in final host
 +
 +
*Gametogeny occurs deep in subepithelial tissue
 +
 +
*Faecal oocyst count is low
 +
 +
*Oocysts are sporulated when passed
 +
**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'''
 +
*Widespread infection but mostly asymptomatic
 +
 +
*Cause meat inspection losses
 +
 +
*''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
    
==Toxoplasma==
 
==Toxoplasma==
Line 151: Line 308:  
***14 weeks before lambing
 
***14 weeks before lambing
 
**The best method of protection is to prevent cats from contaminating the pasture, lambing sheds and feed stores
 
**The best method of protection is to prevent cats from contaminating the pasture, lambing sheds and feed stores
  −
==Sarcocystis==
  −
[[Image:Sarcocystis Life Cycle.jpg|thumb|right|150px|''Sarcocytis'' Life Cycle Diagram - Dennis Jacobs & Mark Fox RVC]]
  −
[[Image:Sarcocystic.jpg|thumb|right|150px|''Sarcocytis'' - Joaquim Castellà Veterinary Parasitology Universitat Autònoma de Barcelona]]
  −
*Most infections are asymptomatic
  −
  −
*Heavy infections are causes of chronic wasting in large animals, hide sondemnation and downgrading of carcasses
  −
  −
*''Sarcocystis'' should be differentiated from other tissue-cyst forming coccidia
  −
  −
*There are many species of ''Sarcocystis'' which differ in size from microscopic to several centimetres in length
  −
**''S.neurona'' is an important equine pathogen in the USA
  −
  −
*Infective cyst in the intermediate host is called a '''sarcocyst'''
  −
  −
'''Life Cycle'''
  −
*Individual life cycles incompletely misunderstood
  −
  −
*Indirect life cycle
  −
  −
*Life cycle alternates between the final and the obligatory intermediate host
  −
  −
*Only '''one''' final and '''one''' intermediate host
  −
  −
*Sporulated oocyst has 2 sporocysts containing 4 sporozoites
  −
**Naked oocyst usually seen in faeces as the oocyst wall is very delicate
  −
**Oocyst measures 15μm in length
  −
  −
*No schizogony in final host
  −
  −
*Gametogeny occurs deep in subepithelial tissue
  −
  −
*Faecal oocyst count is low
  −
  −
*Oocysts are sporulated when passed
  −
**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'''
  −
*Widespread infection but mostly asymptomatic
  −
  −
*Cause meat inspection losses
  −
  −
*''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==
  −
*2 main species
  −
**''Neospora caninum'' in the dog
  −
**''Neospora hughesi'' in the horse
  −
  −
*Sporulated oocysts measuring just 10μm
  −
  −
*Oocyst contains 2 sporocysts with 4 sporozoites
  −
  −
*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''
  −
  −
*Limited range of warm-blooded intermediate hosts
  −
**Asexual reproduction occurs in intermediate host forming tissue cysts
  −
  −
*Host range of sexual stage is unknown for ''N.caninum''
  −
**Intermediate host for ''N.hughesi'' is the horse, but the definitive host is unknown
  −
  −
*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
  −
  −
*''Neospora caninum'' in [[Muscles Inflammatory - Pathology#Protozoa|myositis]]
  −
  −
'''Prevention and Control'''
  −
*Do not allow dogs access to calving cows, placental membranes and aborted or dead calves
  −
  −
*Do not allow dogs to defecate in cattle feeding areas
  −
  −
*Identify and cull seropositive cattle, or do not breed from them or their progeny
  −
  −
*Select seronegative cattle for breeding
  −
  −
*Vaccinate
  −
**Only in the USA
  −
**Neoguard or Intervet
  −
**Killed protozoal vaccine for healthy, preganant cows
  −
**Dosed in first 3 weeks of pregnancy and then every 3-4 weeks during gestation
  −
**Revaccination with 2 doses during each subsequent pregnancy
 
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