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Category: Clinical Microbiology
Tick Systematics and Identification, Page 1 of 2
< Previous page | Next page > /docserver/preview/fulltext/10.1128/9781555816490/9781555812386_Chap07-1.gif /docserver/preview/fulltext/10.1128/9781555816490/9781555812386_Chap07-2.gifAbstract:
Ticks are obligate ectoparasites of terrestrial vertebrates (amphibians, reptiles, birds, and mammals). They belong to the class Arachnida, which as a group are distinguished from the class Insecta by having four pairs of legs as nymphs and adults, lacking both antennae and wings, and having two pairs of appendages associated with their mouthparts, i.e., chelicerae and pedipalps. All ticks and some mites are the only members of the Arachnida that are parasitic. In terms of size, ticks are the largest acarines and can be recognized by their dorsoventrally flattened appearance and by one component of the mouthparts, a hypostome with recurved teeth that acts as a holdfast organ, anchoring the tick to its host. They also possess a unique sensory apparatus, called Haller’s organ on the tarsus of each foreleg. Ticks can be divided into three families, the Argasidae (soft ticks), Ixodidae (hard ticks), and Nuttalliellidae. The last-named family includes a single species from Africa that is infrequently collected, but the other two families are widespread and include many species, some of which may bite humans. While several species of ticks may occasionally attach to humans, relatively few species commonly bite humans, and some of these are vectors of disease-causing pathogens. This chapter considers ticks that are frequently recorded as biting humans. It lists identification guides for ticks that occur in the world’s different zoogeographic regions.
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Line drawings of an ixodid (hard) tick (Ixodes sp.), showing prinicipal dorsal and ventral morphological features, including enlargements of two types of male hypostomes with denticles or crenulations (from reference 47 with permission).
Line drawings of an ixodid (hard) tick (Ixodes sp.), showing prinicipal dorsal and ventral morphological features, including enlargements of two types of male hypostomes with denticles or crenulations (from reference 47 with permission).
Scanning electron micrographs (SEMs) showing dorsal (top) and ventral (bottom) morphology of a larval ixodid (hard) tick. Scale bars, 100 µm. The specimen is Amblyomma falsomarmoreum from the Afrotropical region.
Scanning electron micrographs (SEMs) showing dorsal (top) and ventral (bottom) morphology of a larval ixodid (hard) tick. Scale bars, 100 µm. The specimen is Amblyomma falsomarmoreum from the Afrotropical region.
SEMs showing dorsal (top) and ventral (bottom) morphology of a nymphal ixodid (hard) tick. Scale bars, 200 µm. The specimen is Amblyomma cajennense from the Neotropical and southern Nearctic regions.
SEMs showing dorsal (top) and ventral (bottom) morphology of a nymphal ixodid (hard) tick. Scale bars, 200 µm. The specimen is Amblyomma cajennense from the Neotropical and southern Nearctic regions.
SEMs showing dorsal (top) and ventral (bottom) morphology of a larval argasid (soft) tick. Scale bars, 200 µm. The specimen is Argas cucumerinus from the Neotropical region.
SEMs showing dorsal (top) and ventral (bottom) morphology of a larval argasid (soft) tick. Scale bars, 200 µm. The specimen is Argas cucumerinus from the Neotropical region.
SEMs showing dorsal (top) and ventral (bottom) morphology of an adult Argas sp. soft tick. Scale bars, 1,000 µm. The upper specimen is a male Argas reflexus from the Palearctic region; the lower specimen is a female A. cucumerinus from the Neotropical region.
SEMs showing dorsal (top) and ventral (bottom) morphology of an adult Argas sp. soft tick. Scale bars, 1,000 µm. The upper specimen is a male Argas reflexus from the Palearctic region; the lower specimen is a female A. cucumerinus from the Neotropical region.
SEMs showing dorsal (top) and ventral (bottom) morphology of an adult Ornithodoros sp. soft tick. Scale bars, 500 µm (top) and 1,000 µm (bottom). The specimens are male Ornithodoros capensis ticks; this species occurs almost worldwide in tropical, subtropical, and warm temperate maritime regions.
SEMs showing dorsal (top) and ventral (bottom) morphology of an adult Ornithodoros sp. soft tick. Scale bars, 500 µm (top) and 1,000 µm (bottom). The specimens are male Ornithodoros capensis ticks; this species occurs almost worldwide in tropical, subtropical, and warm temperate maritime regions.
SEMs showing dorsal (top) and ventral (bottom) morphology of an adult Amblyomma sp. hard tick. Scale bars, 500 µm. The specimen (both figures) is a male A. cajennense tick; this species occurs in the Neotropical and southern Nearctic regions.
SEMs showing dorsal (top) and ventral (bottom) morphology of an adult Amblyomma sp. hard tick. Scale bars, 500 µm. The specimen (both figures) is a male A. cajennense tick; this species occurs in the Neotropical and southern Nearctic regions.
SEMs showing dorsal (top) and ventral (bottom) morphology of an adult Dermacentor sp. hard tick. Scale bars, 1,000 µm. The specimen is a female D. andersoni tick; this species occurs in the Nearctic region.
SEMs showing dorsal (top) and ventral (bottom) morphology of an adult Dermacentor sp. hard tick. Scale bars, 1,000 µm. The specimen is a female D. andersoni tick; this species occurs in the Nearctic region.
SEMs showing dorsal (top) and ventral (bottom) morphology of an adult Hyalomma sp. hard tick. Scale bars, 1,000 µm. The specimen is a female H. truncatum tick; this species occurs in the Afrotropical region, although a few have been collected from the southern Palearctic region. Note: some leg segments were removed from this specimen as part of another study.
SEMs showing dorsal (top) and ventral (bottom) morphology of an adult Hyalomma sp. hard tick. Scale bars, 1,000 µm. The specimen is a female H. truncatum tick; this species occurs in the Afrotropical region, although a few have been collected from the southern Palearctic region. Note: some leg segments were removed from this specimen as part of another study.
SEMs showing dorsal (top) and ventral (bottom) morphology of an adult Ixodes sp. hard tick. Scale bars, 500 µm. The specimen is a male I. ricinus tick; this species occurs in the Palearctic region. Note: some leg segments were removed from this specimen in connection with another study.
SEMs showing dorsal (top) and ventral (bottom) morphology of an adult Ixodes sp. hard tick. Scale bars, 500 µm. The specimen is a male I. ricinus tick; this species occurs in the Palearctic region. Note: some leg segments were removed from this specimen in connection with another study.
SEMs showing dorsal (top) and ventral (bottom) morphology of an adult Rhipicephalus sp. hard tick. Scale bars, 500 µm. The specimen is a female Rhipicephalus appendiculatus tick from the Afrotropical region.
SEMs showing dorsal (top) and ventral (bottom) morphology of an adult Rhipicephalus sp. hard tick. Scale bars, 500 µm. The specimen is a female Rhipicephalus appendiculatus tick from the Afrotropical region.
Tick identification references organized by zoogeographic region
Tick identification references organized by zoogeographic region