Current Trends in Immunity and Respiratory Infections - Hardcoverby Nikolas Stephen (Editor) Respiratory infections or respiratory tract infections (RTIs) are infections that lead to diseases that affect the respiratory tract. Infections of the respiratory tract may be caused due to microbes like virus, bacteria, and fungi. The common respiratory tract infections include common cold, pneumonia, bronchitis and tonsillitis. All beings have an innate ability to resist and fight with infection causing agents and this