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The typical flea is usually less than one-eighth of an inch long. Its smooth body is covered with a hard outer skeleton, and extending along the back are several rows of backward-pointing bristles and spines. Unlike the bodies of most insects, the flea's body is flattened from side to side, enabling it to move easily and quickly through hair or feathers. Fleas can leap long distances because of their strong slender legs. Some fleas, for example, can jump higher than 7 inches and farther than 13 inches.
A flea is any of a large group of small wingless insects that feed on the blood of many warm-blooded animals.
Fleas are common throughout the world, but they are particularly numerous in tropical regions. In addition to being annoying pests, some fleas can transmit disease.
Usually each kind of flea attacks only one kind of animal. If the usual hosts are not available, however, most fleas readily attack other animals. For example, the cat flea (Ctenocephalides felis) also attacks dogs, man, and rodents, and the human flea (Pulex irri-tans} often attacks pigs. Only adult fleas suck blood. Although they usually feed once a day, some, such as the human flea, can live for several months without eating. Most fleas leave their host after feeding and live in the host's nest or surroundings. Later they again attack the same host or find another. However, some fleas remain attached to their host. For example, stick-tight fleas (Echidnophaga gallinacea) often gather in clusters on the heads of chickens, cats, and dogs.
Some fleas can transmit serious diseases to man. The oriental rat flea (Xenopsylla cheopis) is the chief carrier of the bacteria that cause bubonic plague, an infectious and often fatal disease. The cat flea, which also attacks other animals, can infect man with a tapeworm common in cats and dogs. The chigoe (Tunga penetrans), also known as the sand flea, often burrows under the skin, causing serious ulcers.
Like many other parasites of warm-blooded animals, fleas reproduce throughout the year. Their small oval white eggs are deposited on the host, in the host's nest, or on the ground. In 2 to 14 days the eggs hatch into larvae, slender white animals without legs and eyes. The larvae feed on the wastes of adult fleas and other animals until they are fully grown. Each larva then spins a silken cocoon in which it pupates. The adult flea emerges from a week to several months later. Fleas live longer than most insects. Some species, such as the human flea, live 2 or more years.
Fleas are often found in barns, stables, chicken coops, and other places where animals are kept. Sometimes they are also brought into homes by cats, dogs, and other pets. Once a home or a pet is infested with fleas, anyone living in the house or coming in contact with the pet may also be attacked. One method of ridding an animal of fleas is to dust it with a commercial flea powder. Fleas can usually be eliminated from houses by spraying basements, floors, and rugs with a kerosene emulsion or an oil base spray.