orthomyxoviridae family. It attacks the respiratory tract in humans (nose, throat, and lungs) characterized by headaches, muscle aches, fever, weakness, and cough. It is caused by one of three strains of influenza virus (A, B, and C).">Influenza (or as it is commonly known, the orthomyxoviridae family. It attacks the respiratory tract in humans (nose, throat, and lungs) characterized by headaches, muscle aches, fever, weakness, and cough. It is caused by one of three strains of influenza virus (A, B, and C).">flu or the grippe) is a contagious disease caused by an RNA virus of the orthomyxoviridae family. It attacks the respiratory tract in humans (nose, throat, and lungs) characterized by headaches, muscle aches, fever, weakness, and cough. It is caused by one of three strains of orthomyxoviridae family. It attacks the respiratory tract in humans (nose, throat, and lungs) characterized by headaches, muscle aches, fever, weakness, and cough. It is caused by one of three strains of influenza virus (A, B, and C).">influenza virus (A, B, and C).