animals that do harm to man directly (for example, by infesting him or by transmitting to him the causative agents of diseases) or indirectly by causing damage to livestock, crops, trees, and so forth.
External and internal parasites are directly harmful to man. The external parasites are mostly insects: lice, bedbugs, fleas, and such two-winged bloodsucking insects as mosquitoes, buffalo gnats, biting midges, and horseflies. Ixodoid ticks are external arachnid parasites. Many worms (helminths, which cause helminthiases) and protozoans are internal parasites.
Animal pests also include a variety of insects and ticks that transmit the causative agents of viral, bacterial, and protozoan diseases of man. Man is also subject to the effects of poisonous animals, which inject toxins through their bites: snakes (for example, the cobra, viper, adder), poisonous spiders (for example, the karakurt), scorpions, and blood-sucking insects and ticks that inject toxic saliva after puncturing the skin. Parasites, transmitters of various diseases, and venomous animals injure domestic and game animals. The diseases caused by parasites (for example, warble fly, itch mite, helminth) and transmitted diseases decrease the productivity of cattle and often kill them. Many rodents (rats, mice, and so forth) are pests. A number of animal pests injure bees and silkworms.
Some insects (for example, moths) and mites damage woolen fabrics, leather, and fur. Termites destroy wooden structures. A number of insects injure stored lumber and wooden furniture (for example, furniture beetles). The bandicoot rat sometimes destroys dams, which may result in floods. Certain mollusks (wood borers) attack wooden underwater structures and wooden ships.
E. N. PAVLOVSKII