The correct answer is option 4, Tetanus. Tetanus is not caused by a virus, but by a bacterium called Clostridium tetani. Tetanus is a serious bacterial infection that affects the nervous system and can lead to muscle stiffness and spasms. It is usually contracted through a puncture wound or a contaminated wound where the bacteria can enter the body and produce a toxin.

Option 1, Chickenpox, is caused by the varicella-zoster virus. It is a highly contagious viral infection that causes an itchy rash and flu-like symptoms.

Option 2, Measles, is caused by the measles virus. It is a highly contagious viral infection that affects the respiratory system and can lead to a characteristic rash.

Option 3, Poliomyelitis (polio), is caused by the poliovirus. Polio is a viral infection that affects the nervous system and can lead to muscle weakness, paralysis, and even death if it affects the muscles that control breathing.

Therefore, all the options except for option 4 are diseases caused by viruses.