Correct option is B
Correct Answer: (b)
Explanation: Tetanus is not caused by a virus but by a bacterium, Clostridium tetani. The disease results from a neurotoxin (tetanospasmin) produced by the bacterium, leading to muscle rigidity and spasms. In contrast, smallpox, rubella, and measles are all caused by viruses. Hence, tetanus is the only non-viral disease among the options.
Information Booster
· Smallpox is caused by the Variola virus.
· Rubella is caused by the Rubella virus, a togavirus.
· Measles is caused by the Measles virus, a paramyxovirus.
· Tetanus toxin interferes with inhibitory neurotransmitter release.
· Vaccination is effective against both viral diseases listed and tetanus.
Additional Knowledge
Tetanus is a toxin-mediated disease rather than an infection caused by active bacterial spread in the body. Clostridium tetani spores are commonly found in soil and enter the body through wounds, where they germinate under anaerobic conditions. Viral diseases such as smallpox, rubella, and measles spread through direct contact or respiratory routes and involve viral replication within host cells, clearly distinguishing them from tetanus.
