Which of the following statements reflects the pathogenesis of influenza？
A. The virus enters the host in airborne droplets
B. Viremia is common
C. The virus frequently establishes persistent infections in the lung
D. Pneumonia is not associated with secondary bacterial infections
E. Viral infection does not kill cells in the respiratory tract
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Which of the following statements concerning antigenic drift in influenza viruses is correct?
A. It results in major antigenic changes
B. It results in new subtypes over time
C. It is exhibited only by influenza A viruses
D. It is caused by frameshift mutations in viral genes
E. It affects predominantly the matrix protein
Which of the following statements about isolation of influenza viruses is correct?
A. Primary influenza virus isolates grow readily in cell culture
B. Diagnosis of an influenza virus infection can only be made by isolating the virus
C. Isolation of virus can help determine the epidemiology of the disease
D. Isolation of influenza virus is done using newborn mice.
A 2-month-old infant developed a respiratory illness that the pediatrician diagnosed as bronchiolitis（细支气管炎）. The most likely cause of the disease is
A. Parainfluenza virus type 4
B. Respiratory syncytial virus
C. Influenza virus
D. Metapneumovirus
E. Measles virus
A 20-month-old boy had an illness characterized by fever, irritability, conjunctivitis, and a brick-red rash initially on the face but spreading downward and outward. At age 9 years, the boy had a gradual onset of severe, generalized neurologic deterioration. Subacute sclerosing panencephalitis (SSPE) was diagnosed. Which of the following statements about SSPE is correct?
A. Rapidly progressive deterioration of brain function occurs
B. The disease is a rare, late complication of rubella infection
C. The incidence of the disease is rising since the introduction of MMR vaccine
D. High titers of measles antibody are found in cerebrospinal fluid
E. Defective varicella-zoster virus is present in brain cells.
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