Neospora Flashcards
Which species are affected by Neospora caninum?
Cattle and Dogs
How do Neospora diseases differ in cattle and dogs?
Disease in dogs – neonatal paresis
Disease in cattle – abortion
What kind of parasite is Neospora caninum?
Apicomplexan protozoa
What are the 3 life cycle stages of Neospora caninum?
- Tachyzoite
- Bradyzoite
- Oocyst
What is the definitive host of Neospora caninum?
Dogs
What is the intermediate host of Neospora?
Dogs
Cattle
How does disease transmission of Neospora occur?
Horizontal transmission e.g. dog to cow, dog to dog
Vertical transmission - to offspring
Describe the life cycle of Neospora, through both hosts
- Bradyzoites released in dog duodenum
- Unsporulated oocyst passed in dog faeces
- Becomes sporulated in food, water or soil
- Ingested by intermediate host
- Becomes a cyst in the muscle tissue of the intermediate host
- Dog ingests tissue cysts
Describe the life cycle of Neospora from a dog to a cow to a foetus
= Exogenous transplacental transmission
- Oocysts excreted in dog faeces, contaminate food and water, ingested by pregnant cows
- Tachyzoites cross the placenta and infect the foetus
What are the two outcomes for an infected foetus?
- Abortion
- Persistent infection
Describe the life cycle of Neospora from a cow to a foetus, without the definitive host
- Endogenous transplacental transmission
- Persistently infected cow – recrudescence of infection
- Slow growing bradyzoites persist within the tissue cysts in neural tissue
- Cow doesn’t show any clinical signs
- During pregnancy bradyzoites differentiate into rapidly dividing tachyzoites – thought to be due to a drop in the cows immunity during pregnancy
What are the consequences for the calf if infected in each of the 3 pregnancy trimesters?
1 - early embryonic death
2- foetal death, abortion, born with congenital defects
3 - weak, brain damaged or normal
How can abortion due to Neospora caninum be diagnosed?
Maternal serology - ELISA - test for antibodies in the second half a pregnancy
Foetus - antibody detection in foetal fluids
Foetal histology of brain or heart
How can endogenous transmission of Neospora be controlled?
- Identification of positive cows: serology of the whole herd
- Cull infected cows
- Embryo transfer, insuring recipients are negative
How can exogenous transmission of Neospora be controlled?
- reduce the risk of infection of dogs
- dispose of afterbirth and aborted material
- minimise risk of contamination of cattle feed with dog faeces
- no current drug development or vaccine
