Rats cause a lot of damage. As the teeth of rodents continue to grow over their lifetime, they need to gnaw on hard substances such as lead and plastic pipes, insulation material and electric wiring. This habit increases the risk of short circuits and fires. In addition to this, they transmit a number of dangerous diseases such as Salmonella, Leptospirosis (Weil's disease), Tuberculosis and even tape worms. Rats cause a lot of contamination. One single rat equals more than 25000 droppings per year, which contain allergens that can cause acute allergic reactions. Rats introduce secondary pests. Rats are also known to introduce other pests, such as fleas, mites and ticks into the premise, causing additional damage. .