Influenza Viruses

A 35-year-old woman from Delhi presents with fever, myalgia, and cough for 3 days during the winter season. Rapid influenza diagnostic test (RIDT) is positive. Which structural feature would best help differentiate whether this is influenza A or influenza B infection based on virion morphology and genetic organization?

A 72-year-old man with chronic obstructive pulmonary disease (COPD) and diabetes mellitus presents to hospital with a 4-day history of fever, productive cough with purulent sputum, dyspnea, and chest pain. He reports influenza-like illness in his community 1 week ago. Rapid influenza diagnostic test is positive for influenza A. Chest X-ray shows left lower lobe consolidation. Blood culture grows Streptococcus pneumoniae. Which of the following best explains the pathophysiology of secondary bacterial pneumonia in this patient?

A 52-year-old man with type 2 diabetes mellitus and COPD presents with acute influenza B infection confirmed by RT-PCR. He is allergic to oseltamivir (rash). Which is the preferred alternative antiviral agent?

During an influenza outbreak in a hospital, a 68-year-old man with COPD presents with fever, cough, and dyspnea on day 3 of illness. Rapid antigen test is positive for influenza A. The infection control team needs to identify the strain and assess for antiviral resistance. Which investigation is most appropriate for this purpose?

A 32-year-old woman presents to the emergency department with a 2-day history of fever (39.5°C), myalgia, cough, and sore throat during the influenza season. Rapid antigen test (RAT) for influenza is negative. Clinical suspicion for influenza remains high. What is the most appropriate next investigation to confirm the diagnosis?