General Parasitology and Protozoa
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. 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.