Pneumonia Caused by Emerging Viral Agents

Emerging viruses that cause pneumonia in humans are agents which normally circulate in the animal population but can move to human hosts under certain circumstances, which determines the occurrence of a new type of disease. The Middle East respiratory syndrome (MERS) is caused by a coronavirus. The disease has a wide symptomatic spectrum that can range from asymptomatic infections to fulminant respiratory failure. Diagnostic confirmation is achieved through viral isolation. Severe acute respiratory syndrome (SARS), also produced by a coronavirus, is capable of producing a serious pulmonary disease outbreak with no reappearance. The clinical presentation includes fever, malaise, cough, and headache followed by diarrhea. Other coronaviruses (HCoV-NL63 and HCoV-HKU1) can cause serious lower respiratory infections in small children, the elderly, and immunosuppressed patients. Influenza virus is widespread in nature, and avian virus may spread to humans, as has been reported with H7N9, H5N1, H10N8, and H6N1. Cardiopulmonary hantavirus syndrome, a feverish disease characterized by respiratory insufficiency and shock, is produced by Andes virus. Other emerging viruses are enterovirus D68 and polyomavirus.