Rodents are among the most important competitors with humans for food and other resources. It has been estimated that worldwide there is one rat for every human being. Both rats and mice constitute a major threat to mankind because of the disease organisms they harbor and damage they cause. The Food and Agricultural Organization of the United Nations reported worldwide, rats destroy more than 42 million tons of food worth $30 billion. Other reports indicate that one-fifth to one-third of all the world's food crops are consumed or contaminated by rats each year. Moreover, in the past century alone, more than 10 million people have died from rodent-borne diseases. Thus, rodent pest management is essential to achieving and maintaining an acceptable standard of living.
In the United States, the adoption of rodent control measures by homeowners, public health and professional pest control personnel has prevented the extreme losses seen in some developing countries. Nonetheless, each year an estimated 50,000 Americans, mostly children, are bitten by rats. Property losses include millions of dollars worth of food consumed or contaminated on farms and in warehouses. In addition, numerous building fires are attributed to rodents chewing gas pipes or stripping insulation from electrical wires. Furthermore, the diseases carried by rodents in this country are numerous and include, dysentery, hantavirus pulmonary syndrome, leptospirosis, lymphocytic choriomeningitis, murine typhus, rabies, rickettsial pox, salmonellosis, trichinosis and tularemia. And each year, the several human deaths in the Western states resulting from rodent-borne sylvatic plague serve to remind us of the potential for disaster if we relax rodent control measures .
In addition to spreading human diseases or causing damage to buildings and their contents, rodents can severely affect the health of farm and domestic animals. Rat attacks on animals such as newborn pigs and poultry cause death and mutilation, and numerous animals suffer illness or death from rodent-borne diseases.