There are many genera and species of ticks in the families Ixodidae (hard ticks) that are of public health importance. Some representative genera, and diseases they are known vectors for, include: Amblyomma (tularemia, ehrlichiosis, Rocky Mountain spotted fever [RMSF], boutonneuse fever); Dermacentor (RMSF, Colorado tick fever, tularemia, Siberian tick typhus, and Central European tick-borne encephalitis, as well as being an agent of tick paralysis); Hyalomma (Siberian tick typhus, Crimean-Congo hemorrhagic fever); Ixodes (Lyme disease, babesiosis , human granulocytic ehrlichiosis, Russian spring-summer encephalitis); and Rhipicephalus (RMSF and boutonneuse fever).
Members of the family Ixodidae undergo either one-host, two-host or three-host life cycles. During the one-host life cycle, ticks remain on the same host for the larval, nymphal and adult stages, only leaving the host prior to laying eggs. During the two-host life cycle, the tick molts from larva to nymph on the first host, but will leave the host between the nymphal and adult stages. The second host may be the same individual as the first host, the same species, or even a second species. Most ticks of public health importance undergo the three-host life cycle, whereby the tick leaves the host after the larval and nymphal stages. The three hosts are not always the same species, but may be the same species, or even the same individual, depending on host availability for the tick.
Molecular Biology and Genetics
Statistics of barcoding coverage
|Specimen Records:||2,345||Public Records:||727|
|Specimens with Sequences:||1,786||Public Species:||82|
|Specimens with Barcodes:||1,615||Public BINs:||110|
|Species With Barcodes:||129|
They are distinguished from the other main family of ticks, the soft ticks (Argasidae) by the presence of a scutum or hard shield. In both the nymph and the adult, a prominent capitulum (head) projects forwards from the animal's body; in the Argasidae, conversely, the capitulum is concealed beneath the body.
The family contains these genera:
- Amblyomma – 130 species (includes some of Aponomma)
- Anomalohimalaya – three species
- Bothriocroton – seven species
- Cosmiomma – one species
- Cornupalpatum – one species
- Compluriscutula – one species
- Dermacentor – 34 species (includes Anocentor)
- Haemaphysalis – 166 species
- Hyalomma – 27 species
- Ixodes – 243 species
- Margaropus – three species
- Nosomma – two species
- Rhipicentor – two species
- Rhipicephalus – 82 species (includes Boophilus)
- D. H. Molyneux (1993). "Vectors". In Francis E. G. Cox. Modern parasitology: a textbook of parasitology (2nd ed.). Wiley-Blackwell. pp. 53–74. ISBN 978-0-632-02585-5.
- Alberto A. Guglielmone, Richard G. Robbing, Dmitry A. Apanaskevich, Trevor N. Petney, Agustín Estrada-Peña, Ivan G. Horak, Renfu Shao & Stephen C. Barker (2010). "The Argasidae, Ixodidae and Nuttalliellidae (Acari: Ixodida) of the world: a list of valid species names" (PDF). Zootaxa 2528: 1–28.