Toxoplasma

Question 1

Sample and method

Answer 1

Sabin-Feldman antibody dye test- disable tachyzoites by methylene blue!
Complement fix
Serological
Histo sample of brain/ muscle-HE
Mouse inoculation
Cannot distinguish from Hammondia hammondi

Question 2

Diagnosis

Answer 2

Unsporulated oocysts in cat faeces

Patency max= 20 days

Question 3

Position of parasite

Answer 3

Develops in intestinal epithelia, all cells are infected

Question 4

Shape

Answer 4

Sporulated oocyst

2 sporocysts with 4 sporozoites each

Question 5

Host and vector

Answer 5

FH: cats and lions
IH: mammals and birds
infection from oocysts in the environment or ingestion from IM host e.g cow

Facultative heteroxenous
V. euryxenous

Question 6

Life cycle and development

Answer 6

1) the oocysts in the faeces become sporozoites
2) acute inf: the sporozoites become tachyzoites
3) tachyzoites find cell to infect– immune system– becomes bradyzoite in cyst! this is in the case of chronic infection

Develops in intestinal ep, but can survive in extraintestinal tissues

Question 7

Morph of tachyzoite/trophozoite

Answer 7

Divide by endodyogeny (special type of binary fission)
Long and thin
Giemsa
May also be found in cysts without a wall

Question 8

Clinical signs

Answer 8

Symptomless
Acute: Dx, fever, depression
Cats: pneumonia, encephalitis, enteritis
Dogs: CNS symptoms
Human: mental disorder, newborn blindness, miscarriage

Question 9

Patho signs

Answer 9

Related to extraintestinal!
Rabbits: disseminated: necrotic foci/granulomas in liver, spleen, lungs
Dogs: disseminated in conjunction with Rubarth’s/ canine distemper
Sheep and goat: white-yellow necrotic spots on the placenta