section_path: Interaction with humans/As pests and disease vectors
section_name: As pests and disease vectors
paragraph_text: As pests and disease vectors
  
  Some rodent species are serious agricultural pests, eating large quantities of food stored by humans. For example, in 2003, the amount of rice lost to mice and rats in Asia was estimated to be enough to feed 200 million people. Most of the damage worldwide is caused by a relatively small number of species, chiefly rats and mice. In Indonesia and Tanzania, rodents reduce crop yields by around fifteen percent, while in some instances in South America losses have reached ninety percent. Across Africa, rodents including Mastomys and Arvicanthis damage cereals, groundnuts, vegetables and cacao. In Asia, rats, mice and species such as Microtus brandti, Meriones unguiculatus and Eospalax baileyi damage crops of rice, sorghum, tubers, vegetables and nuts. In Europe, as well as rats and mice, species of Apodemus, Microtus and in occasional outbreaks Arvicola terrestris cause damage to orchards, vegetables and pasture as well as cereals. In South America, a wider range of rodent species, such as Holochilus, Akodon, Calomys, Oligoryzomys, Phyllotis, Sigmodon and Zygodontomys, damage many crops including sugar cane, fruits, vegetables, and tubers.
  
  Rodents are also significant vectors of disease. The black rat, with the fleas that it carries, plays a primary role in spreading the bacterium Yersinia pestis responsible for bubonic plague, and carries the organisms responsible for typhus, Weil's disease, toxoplasmosis and trichinosis. A number of rodents carry hantaviruses, including the Puumala, Dobrava and Saaremaa viruses, which can infect humans. Rodents also help to transmit diseases including babesiosis, cutaneous leishmaniasis, human granulocytic anaplasmosis, Lyme disease, Omsk hemorrhagic fever, Powassan virus, rickettsialpox, relapsing fever, Rocky Mountain spotted fever, and West Nile virus.
  
  Because rodents are a nuisance and endanger public health, human societies often attempt to control them. Traditionally, this involved poisoning and trapping, methods that were not always safe or effective. More recently, integrated pest management attempts to improve control with a combination of surveys to determine the size and distribution of the pest population, the establishment of tolerance limits (levels of pest activity at which to intervene), interventions, and evaluation of effectiveness based on repeated surveys. Interventions may include education, making and applying laws and regulations, modifying the habitat, changing farming practices, and biological control using pathogens or predators, as well as poisoning and trapping. The use of pathogens such as Salmonella has the drawback that they can infect man and domestic animals, and rodents often become resistant. The use of predators including ferrets, mongooses and monitor lizards has been found unsatisfactory. Domestic and feral cats are able to control rodents effectively, provided the rodent population is not too large. In the UK, two species in particular, the house mouse and the brown rat, are actively controlled to limit damage in growing crops, loss and contamination of stored crops and structural damage to facilities, as well as to comply with the law.