Bedbugs, Lice and Ticks (Who)
BEDBUGS: PUBLIC HEALTH IMPORTANCE
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CHAPTER 4
Bedbugs, fleas, lice, ticks and mites
Ectoparasites that live on the body, in clothing and in beds
There are many different species of bloodsucking fleas, lice, ticks and mites. Lice live on humans or in their clothing, while fleas are frequently found taking bloodmeals on people and domestic animals. Bedbugs, which can be found in beds or furniture, feed on humans to obtain blood-meals. Some mites live in people’s skin, e.g. the mites that cause scabies. Other mite species and ticks may take bloodmeals on humans. Fleas, bedbugs and lice are insects, whereas ticks and mites belong to another group of arthropods, the Acarina. Unlike adult insects they have only two main sections to their body, and the adults have four pairs of legs (as opposed to three pairs in insects). Bedbugs, head lice and crab lice do not carry disease, but their biting can be a serious nuisance. However, important diseases of humans and animals are transmitted by other arthropods dealt with here, among them the following: — — — — epidemic typhus and epidemic relapsing fever (body lice); plague and murine typhus (certain fleas); Lyme disease, relapsing fever and many viral diseases (ticks); scrub typhus (biting mites).
BEDBUGS
Two species of bedbug feed on humans: the common bedbug (Cimex lectularius), which occurs in most parts of the world, and the tropical bedbug (Cimex hemipterus), which occurs mainly in tropical countries. They are a severe nuisance when they occur in large densities, being commonest in places with poor housing conditions. They are not important in the transmission of diseases, although they possibly play a role as vectors of hepatitis B virus.
Biology
Bedbugs have a flat, oval-shaped body with no wings, and are 4–7 mm long. Their colour is shiny reddish-brown but after a blood-meal they become swollen and dark brown in colour. There are three stages in the bedbug’s life cycle: egg, nymph and adult (Fig. 4.1).
237
CHAPTER 4
Bedbugs, fleas, lice, ticks and mites
Ectoparasites that live on the body, in clothing and in beds
There are many different species of bloodsucking fleas, lice, ticks and mites. Lice live on humans or in their clothing, while fleas are frequently found taking bloodmeals on people and domestic animals. Bedbugs, which can be found in beds or furniture, feed on humans to obtain blood-meals. Some mites live in people’s skin, e.g. the mites that cause scabies. Other mite species and ticks may take bloodmeals on humans. Fleas, bedbugs and lice are insects, whereas ticks and mites belong to another group of arthropods, the Acarina. Unlike adult insects they have only two main sections to their body, and the adults have four pairs of legs (as opposed to three pairs in insects). Bedbugs, head lice and crab lice do not carry disease, but their biting can be a serious nuisance. However, important diseases of humans and animals are transmitted by other arthropods dealt with here, among them the following: — — — — epidemic typhus and epidemic relapsing fever (body lice); plague and murine typhus (certain fleas); Lyme disease, relapsing fever and many viral diseases (ticks); scrub typhus (biting mites).
BEDBUGS
Two species of bedbug feed on humans: the common bedbug (Cimex lectularius), which occurs in most parts of the world, and the tropical bedbug (Cimex hemipterus), which occurs mainly in tropical countries. They are a severe nuisance when they occur in large densities, being commonest in places with poor housing conditions. They are not important in the transmission of diseases, although they possibly play a role as vectors of hepatitis B virus.
Biology
Bedbugs have a flat, oval-shaped body with no wings, and are 4–7 mm long. Their colour is shiny reddish-brown but after a blood-meal they become swollen and dark brown in colour. There are three stages in the bedbug’s life cycle: egg, nymph and adult (Fig. 4.1).