Pulex irritans, or human flea, is a tiny bloodsucking insect that can be found on almost every continent. It was a common nuisance in rich and poor families during the Middle Ages, but was rarely found indoors in 2011. These insects often irritate the skin when they bite human hosts. They are also capable of spreading serious illness from one person to another.
A human flea can feed on skunks.
The human flea is less common than other varieties such as mouse or cat fleas. This species usually breeds around styes. Human fleas primarily prefer pig and human blood, but they also feed on the blood of badgers, foxes, skunks, and some other wild mammals.
Pulex irritans fleas are usually between a sixteenth and an eighth of an inch in length (1.587 to 3.175 mm). They have dark brown or black bodies, with long, spiny legs; short articulated antennae; flat sides; and without wings. They move from place to place by crawling or jumping. A human flea can jump up to 100 times its body size.
The human flea can transmit bacteria from mice to humans.
These insects have piercing and sucking mouthparts. Its saw-like jaws cut through the host’s flesh and release an anticoagulant into the skin to prevent the blood from clotting as the insect feeds. They then suck blood from the human or animal host. Fleas can live for months or years without feeding when no acceptable hosts are available.
Female fleas lay eggs on the bodies of their hosts. The eggs are not barbed or sticky and do not stick to the host, so they often fall from the animal to the bedding. The eggs hatch into white, worm-like, legless larvae. Human flea larvae feed on adult fecal matter and animal organic material.
Young fleas shed their exoskeletons three times before entering the pupal stage. They mature inside silk cocoons and come out as adults. The maturation process usually takes three to four weeks, depending on climate and host availability.
Human flea bites often leave small red, itchy marks on hosts when they feed. Some people are more sensitive to flea bites than others. The anticoagulant in human flea saliva can cause severe itching or rash. Scratching flea bites can lead to secondary infections.
Pulex irritans is able to spread the Yersinia pestis bacteria from mice to humans. This bacterium causes the bubonic plague, a serious disease that killed an estimated 200 million people during the 14th century in a pandemic called the Black Death. Plague outbreaks were still occurring in 2011, but antibiotics greatly improved the survival rate of infected patients.