Neosporosis

Question 1

Neospora caninum final host

Answer 1

dog

Question 2

Neospora caninum location

Answer 2

IH: muscle
FH: SI

Question 3

Neospora caninum intermediate host

Answer 3

equine, ruminants

Question 4

Neospora caninum life cycle

Answer 4

) Unsporulated oocyst sporulates in the environment within 1-3 days in favorable conditions (warmth and moisture) and become INFECTIVE. Each sporulated oocyst contain 2 sporocysts, each with 4 sporozoites.
2) The intermediate host ingest the sporulated oocyst from contaminated feed, water or pasture. They excyst and sporozoites are released in intestine. Inside intestinal cells, they multiply as TACHYZOITES (fast replication) and later form BRADYZOITES (slowly replicating, encyst in tissue). Tachyzoites can cross placenta and cause VERTICAL transmission (abortion or congenital infection).
3) Final host (dog) becomes infected by eating IH tissue cysts (bradyzoites). Bradyzoites are released and initiated Merogony, and then Gametogony formation in the small intestine. Oocysts are produced after sexual reproduction, and unsporulated oocysts are shed in the feces.

Question 5

Neospora caninum transmission

Answer 5

• Transplacental (vertical)
• Ingestion of meat / oocyst

Question 6

Neospora caninum pathogenesis

Answer 6

Villous atrophy, cyst formation in muscle and CNS.

IH: Tachyzoites spread rapidly through bloodstream to various organs, especially placenta and fetus causing placentitis, fetal tissue destruction (esp. brain, heart, liver) and then abortion of persistent infection in fetus.
Bradyzoites form tissue cysts and can persist, causing reactivation and repeated abortions.

FH: neuromuscular disease is the main problem
Tachyzoites replication in neural and muscular tissue leads to inflammation, necrosis and demyelination.

Question 7

Neospora caninum clinical signs

Answer 7

Cows: abortion, stillborn, mummified fetuses
Dogs: paralysis or hind limb weakness, muscle atrophy, seizures or ataxia

Question 8

Neospora caninum diagnosis

Answer 8

• Clinical signs
• PCR, serology
• Histopathology (foetus)

Question 9

Neospora caninum treatment

Answer 9

Dogs:

• Sulfanomides
• sulfadiazine
• sulfadimethoxine
• May be combined with Pyrimethamine / Clindamycin

IH:

• culling of seropositive animals, do not breed
• vaccine in some countries (limited efficacy).

Question 10

Neospora caninum control

Answer 10

Prevent animal contamination in feed, prevent bovine/canine contact with placenta