This is not true. Plantar warts may take from one month to one year to appear after acquiring the virus. The virus often enters through cuts or abrasions on the bottom of the foot. The virus also thrives on warm, humid climates. Shared showers, gym floors, and swimming facilities are common places of infection because of their warm, moist environments.
Prevention consists of avoiding sharing socks, shoes, and showering facilities.
Good pedal hygiene is also helpful in preventing warts. The wart subsides and disappears due to the action of the body's immune system. Plantar warts, left untreated, can lead to pre-cancerous lesions. Treatment of plantar warts varies greatly. There are various options, some of which are covered here.