Human Metapneumovirus (HMPV) Scanning electron micrograph (SEM) of an African Green Monkey Kidney Epithelial cells (Vero cell line) infected with HMPV for 3 days. The image shows an infected cells with long filamentous enveloped particles emerging from the plasma membrane. These infections can cause "cold-like" symptoms similar to other viruses that cause upper and lower respiratory infections (RSV, Rhinovirus, Influenza) ranging from mild symptoms such as cough, fever, nasal congestion, and shortness of breath to more severe bronchitis or pneumonia. Magnification: 3000 x when printed 10 centimetres wide.