Lecture 06 - Toxoplasma

Question 1

What is toxoplasma

Answer 1

a protozoan parasite in the phylum apicomplexa that infects most warm-blooded animals

Question 2

Where do toxoplasma sexually replicate

Answer 2

cats

Question 3

What is unique about toxoplasma

Answer 3

it can invade the host cells and evade the immune system

Question 4

What is a trophozoite

Answer 4

does the invading
has two generations (tachyzoites and bradyzoites)

Question 5

What are tachyzoites

Answer 5

fast multiplying

Question 6

What are bradyzoites

Answer 6

slow multiplying or inert

Question 7

How do trophozoites multiply

Answer 7

asexual multiplication via internal budding

Question 8

What are cysts

Answer 8

the resting/chronic form, has a thick wall to protect it

Question 9

What is a pseudocyst

Answer 9

when mother cell bursts it stays connected for a short period and looks like a cyst

Question 10

Where is the intestinal form found

Answer 10

cats

Question 11

What is the pathogensis of toxoplasma

Answer 11

an intracellular parasite that only invade nucleated cells, cell invasion is facilitated by the apical complex and survival is ensured by the creation of a protective parasitophorous vacuole

Question 12

What is the acute phase of infection

Answer 12

tachyzoites invading cells, cell destruction, mononuclear cell inflammation, blood vessel blockage

Question 13

What is the chronic phase of infection

Answer 13

bradyzoites and tissue cysts, latency/immunological evasion, hyopersensiticity

Question 14

How do they evade the immune system

Answer 14

the walls of tissue cysts are made of the host so not recognize as intruder

Question 15

Sites of invastion

Answer 15

lymph nodes, cardiac or skeletal muscle, brain, eyes

Question 16

What is dangerous about pregnant women

Answer 16

if they are infected for the first time during pregnancy toxoplasma can cross the placenta and cause abortion or congenital defects

Question 17

What happens with toxoplasma and the brain

Answer 17

it infects neurons directly by increasing dopamine synthesis causing a modification of host behaviour

Question 18

What is the association with toxoplasma and human abnormalities

Answer 18

association with increased aggression in women, increase impulsivity in men, homicide rates, suicide rates, schizophrenia

Question 19

Acute disease symptoms

Answer 19

90% asympotomatic

lymphadenopathy
mono like
hepatitis with jaundice
splenomegaly
rash
involvement of CNS an eye (often seen in reactivation)

Question 20

Chronic disease symptoms

Answer 20

always asymptomatic

Question 21

What is ocular toxoplasmosis

Answer 21

when infection gets into the eye and causes hemorrhage or scarring

Question 22

What can transplacental transmission cause

Answer 22

abortion or stillbirth, CNS lesions, blindness, hydrocephaly, cerebral calcifications

Question 23

What is the transmission of toxoplasma

Answer 23

ingestion, transfusion or transplantation, transplacentally, reactivation of chronic infection

Question 24

What is the direct demonstration of toxoplasma

Answer 24

giemsa stain
fluorescent antibody stains
NAAT
animal inoculation/tissue cultures (rarely used)

Question 25

What is the serology of toxoplasma

Answer 25

sabin feldman dye test
immunofluorescent assays
enzyme immunoassays