coccidian parasite is a very important topic for pg entrance........so every important point about it have been discussed in detail......take a look at it...
5. -MODE OF TRANSMISSION :
1) ingestion of sporulated oocyst from contaminated soil,water or food
2) ingestion of tissue cysts containing Bradyzoites from undercooked
meat
3) by blood transfusion or vertical transmission tachyzoites are infective
form
6. -Maximum chances of transmission = 3rd Trimester
-Severity is more if transmission occurs in= 1st trimester
-C/F : 3C + 2M
Chorioretinitis :MC manifestation
Cerebral calcification
Convulsions
Microcephaly
Mental Retardation
13. -Blood smear : shows comma shaped Tachyzoites (Indicates active lesion)
-Biopsy from tisse : Shows tisse cysts wit bradyzoites
(Indicates past or chronic infection)
14.
15. - Gold stadard test
-Highly sensitive and specific test
-But can not distinguish between recent or past infection
-Antibody detection test
16. 1) Immunocompetent hosts = No treatmet
2) Toxoplasmosis In Pregnancy = Spiramycin
3) In HIV = Cotrimoxazole
17. Q. A 36-year-old man with AIDS develops right-sided weakness involving
the lower, but not the upper, limb. MRI scans reveal a ring-enhancing
lesion within the white matter of the left frontal lobe. A biopsy shows
coagulative necrosis of brain parenchyma with macrophage-rich chronic
inflammatory infiltration admixed with microscopic cysts that contain
characteristic bradyzoites. Which is the most common source of this type
of infection? (AIPG 2011)
A Anopheles mosquitoes
B Bird droppings
C Cats
D Cooling systems
18. Ans. C Cats
a. This is the history of toxoplasmosis.
b. The commonest source is oocysts shed in the definitive host i.e cat.
The intermediate host is mouse, human.
c. Most of the infections in immunocompetent people are asymptomatic.
d. In immunocompromised people it causes encephalitis (HIV/AIDS).
e. The infection can also be transmitted from the pregnant mother to the
fetus through placenta. The highest chance of transmission in during the
third trimester, however, the infection in the fetus is most severe if the
infection is transmitted in the first trimester of pregnancy.
f. The serological test used for diagnosis is Sabin & Feldman dye test and
ELISA.
19. 2. All of the following statements about toxoplamosis are true except:
A Oocyst in freshly passed cat faeces is non-infectious
B May spread by organ transplantation
C Maternal infection acquired during third trimester has high risk of
transmission
D Arthalgia, sore throat and abdominal pain are the most common
manifestations
20. Ans. D Arthalgia, sore throat and abdominal pain are the most common
manifestations
Definite host in toxoplasmosis is cat.
The intermediate host is man or any other mammal like sheep or pig.
Stages-
a. Trophozoite (tachyzoites): crescent shaped: Indicates ACute Infection
b. Tissue cyst: formed during chronic infection. Skeletal, heart muscle,
brain. 200 m. Bradyzoites
d. Infective form for man-tissue cyst in poorly cooked meat of infected
animal and food or water contaminated by feces with sporulated oocyst.
The oocyst in cat feces becomes infectious in 1-2 days after passage in
cat feces.
e. Common symptoms in immunocompetent people are cervical
lymphadenopathy, fever and malaise.
f. Tissue cyst with bradyzoites in organ can transmit disease via organ
transplantation.
21. 3. Acute toxoplasmosis is commonly associated with all
of the following except (AIIMS May 2011)
A Cervical lymphadenopathy
B Axillary lymphadenopathy
C Muscle pain
D Myocarditis
23. 3. A 24 year old primi in her 8th month of pregnancy develops a positive
igm titer to T. Gondii for the first time. She should be advised by her
physician that
A That this child and all future fetuses would be infected
B That the new born with positive anti-toxoplasma igg response should be
treated with anti-parasitics
C That future infections can be avoided by proper vaccination and
deworming of cats
D That chorioretinitis can be prevented by drug treatment of an infant with
positive igm response.
24. Ans. D That chorioretinitis can be prevented by drug treatment of an
infant with positive igm response.
a. Presence of igm in the primi in 8th month of pregnancy indicates
recent primary infection.
c. Infection acquired in the first trimester by women who were not treated
with anti–T. Gondii drugs results in congenital infection in 10% to 25% of
cases.
d. For second- and third-trimester infections, the incidences of fetal
infection ranged between 30% and 54% and 60% and 65%, respectively.
e. Majority of children born of women who acquire their infection during
the third trimester as in this case are born with the subclinical form of the
infection.
If IgM to toxoplasma is positive in the neonate, then appropriate
treatment will prevent the complication
25. 5. A person who had recently consumed half a box of raspberries came
down with severe watery diarrhoea. What is the most likely diagnosis?
A Cyclospora
B Cryptosporidium
C Isospora
D Vibrio
26. Intake of contaminated raspberries or basil followed
by diarrhea suggests cyclospora infection.
A Cyclospora
27. 6. A person having diarrhea of six month duration. AFB of size 12 micron
are found in stool. Most likely cause is:
A Cryptosporidium
B Isospora
C Cyclospora
D Giardia
28. Ans. C Cyclospora
a. Cyclospora oocysts are of 12 micron size. They contain 2 sporocysts
with 2 sporozoites each.
b. Isospora oocysts are of 20-33 micron size. They contain 2 sporocysts
with 4 sporozoites each.
c. Cryptosporidium oocysts are 4-5 micron in size and contain 4 naked
sporozoites.
d. Giardia cyst are not acid fast.
29. Acid fast staining of stools is used for all except
A Cyclospora caytenensis
B Isospora belli
C Blastocystis hominis
D Cryptosporidium
31. An AIDS patient presents to his primary care physician with a two
week history of watery, nonbloody diarrhea. The most likely diagnosis
is which of the following? (AIIMS May 2012)
A Acid-fast bacilli
B Enterocytozoon
C Cryptosporidium
D Cyclospora
