This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
[{'content': 'The classic triad of congenital rubella includes all except - \nSelect and explain. \nA. Cataract, B. Deafness, C. Retinitis, D. CHD', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Congenital rubella syndrome\n\n\xa0Maternal viremia associated with rubella infection during pregnancy may result in infection of the\n\nplacenta and fetus.\n\n\xa0The most important factor in the pathogenicity of rubella virus for the fetus is the gestational age at the time\n\nof infection.\n“In general, the earlier in pregnancy infection occurs, the greater the damage to the fetus. Maximum\xa0damage to the fetus occurs when infection is acquired in the first trimester of pregnancy”.\n\n\xa0Fetus infected in the twentieth week may have isolated deafness.\n\xa0Clinical manifestations\n\nThe classical triad of congenital rubella consists of cataract, deafness and congenital heart diseases.\n\n\xa0Laboratory diagnosis\n\xa0Isolation of virus in cell cultures of throat samples, urine or other secretions.\n\nNormally, maternal rubella antibodies in the form of IgG is transferred to infants and is\xa0gradually last over a period of 6 months. Persistent beyond 1 year in an un vaccinated child\xa0suggests the diagnosis of congenital rubella.\nPresence of Ig M antibodies is diagnostic.\nPCR for rubella RNA', 'role': 'assistant'}]