Which of the following is not a common route of transmission for pinworm infection?

Pinworm infection, caused by the Enterobius vermicularis parasite, typically spreads through several specific routes. The ingestion of contaminated food occurs when eggs from pinworms, which are often found on contaminated surfaces or transmitted from hands to mouth, are swallowed. Additionally, inhalation of eggs is possible, as tiny pinworm eggs can become airborne and be inhaled, leading to infection if they reach the gastrointestinal tract.

Direct contact with contaminated surfaces also plays a crucial role in the transmission cycle. Pinworm eggs can survive on surfaces like bedding, clothing, or toilet seats, and if a person touches these contaminated areas and then touches their mouth or face, they can become infected.

On the other hand, injection is not a route of transmission for pinworm infection. This mode of transmission is not applicable as pinworm eggs do not enter the body through the bloodstream or via any injectable means. Understanding the common routes of transmission helps in implementing proper hygiene practices to prevent pinworm infections effectively.