Which one of the foil owing diseases is not caused by virus?

Tetanus is not caused by a virus; it is a bacterial disease caused by the toxin-producing bacterium Clostridium tetani [t3]. In contrast, the other options are viral in nature. Chickenpox (Varicella) is caused by the varicella-zoster virus [c1][t1]. Measles is a highly contagious respiratory infection caused by the measles virus [c1][t7][t9]. Poliomyelitis, commonly known as polio, is a viral infection that affects the nerves and brain, often leading to paralysis [t7][t9]. While vaccines exist for all four conditions, the underlying pathogens differ significantly. Tetanus vaccines specifically target the potent toxin produced by the bacteria rather than a viral agent [t3]. Therefore, among the listed diseases, tetanus is the only one of bacterial origin, making it the correct answer to the question regarding which disease is not caused by a virus.

Sources

1. [1] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 3: Health: The Ultimate Treasure > Activity 3.4: Let us find out > p. 33
2. [2] https://doh.wa.gov/you-and-your-family/immunization/diseases-and-vaccines
3. [3] https://www.ncbi.nlm.nih.gov/books/NBK20370/
4. [4] https://www.cdc.gov/vaccines-children/diseases/index.html