Ixodes scapularis
Ixodes scapularis | |
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Adult female deer tick | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Subphylum: | Chelicerata |
Class: | Arachnida |
Order: | Ixodida |
Family: | Ixodidae |
Genus: | Ixodes |
Species: | I. scapularis
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Binomial name | |
Ixodes scapularis Say, 1821
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Synonyms[1] | |
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Ixodes scapularis is commonly known as the deer tick or black-legged tick (although some people reserve the latter term for
Description
As a nymph and adult, Ixodes scapularis has eight legs, while larvae have six.[7] Unlike ticks from other genera,[8] deer ticks do not have eyes.[3][8] The scutum is dark, inornate (plain), and, in unfed females, contrasts with the exposed orange or red remainder of the idiosoma.[3] There are no festoons.[3][9] Ixodes ticks have an anal groove that resembles a horseshoe[9] on their underside anterior to the anal pore.[8][10] The palps of male deer ticks, part of the mouthparts or capitulum, are shorter than those of the female.[7][11]: 5 Adult female deer ticks are approximately 3 to 4 mm long,[10] and may engorge while feeding,[7] while adult males are 2 to 3 mm long[10] and cannot engorge due to the rigidity of their scutum, which covers the entire male body.[7]
Behavior
Ixodes scapularis has a 2-year life cycle, during which time it passes through three stages: larva, nymph, and adult. The tick must take a blood meal at each stage before maturing to the next. Deer tick females latch onto a host and drink its blood for 4–5 days. Deer are the preferred host of the adult deer tick, but it is also known to feed on small rodents.
Like other ticks, I. scapularis is hardy. It can be active after a hard
As disease vector
Ixodes scapularis is the main
It can also transmit other Borrelia species, including Borrelia miyamotoi.[17] Ticks that transmit B. burgdorferi to humans can also carry and transmit several other parasites, such as Babesia microti and Anaplasma phagocytophilum, which cause the diseases babesiosis and human granulocytic anaplasmosis (HGA), respectively.[18] Among early Lyme disease patients, depending on their location, 2%–12% will also have HGA and 2%–40% will have babesiosis.[19]
Co-infections complicate Lyme symptoms, especially diagnosis and treatment. It is possible for a tick to carry and transmit one of the co-infections and not Borrelia, making diagnosis difficult and often elusive. The
Deer, the preferred mammalian hosts of adult I. scapularis, cannot transmit Borrelia spirochaetes to ticks. Ticks acquire Lyme disease microbes by feeding on infected mice and other small rodents as nymphs or larvae.[12]
One of the keys of the success of I. scapularis as a Borrelia vector relies on its ability to limit the proliferation of the spirochaete. This is due to the activity of domesticated amidase effector (dae) genes. Dae genes are a family of horizontally acquired genes related to type VI secretion amidase effector (tae) genes in certain bacteria which encode toxins honed to mediate interbacterial antagonism. Once transferred to eukaryotes tae genes confer novel antibacterial capabilities;[21] this provides a selective advantage to the tick and to other eukaryotes also: tae genes have been transferred from bacteria to eukaryotes at least in six independent events. In particular, I. scapularis have inherited the dae 2 family from a common ancestor between ticks and mites.[21] The product of dae2 expression has been shown to degrade bacterial peptidoglycan of different species and particularly from B. burgdorferi, but does not limit initial acquisition of the bacterium by the tick. Dae2 contributes to the innate ability of I. scapularis to control B. burgdorferi levels after its acquisition. This has potential ramifications for Lyme disease transmission, as spirochaete load in the tick can influence transmission efficiency.[21][22]
A recent study has identified the
Genome sequencing
NCBI genome ID | 523 |
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Ploidy | diploid |
Genome size | 1,765.38 Mb |
Number of chromosomes | 15 pairs |
Year of completion | 2008 |
The genome of I. scapularis has been sequenced.[24]
See also
References
- ^ "Ixodes scapularis Say, 1821". Global Biodiversity Information Facility. Retrieved 11 April 2024.
- ISBN 978-0-89997-353-1.
- ^ a b c d Patnaude, Michael R.; Mather, Thomas N. (December 2014) [Originally published July 2000]. Rhodes, Elena (ed.). "Deer tick, Ixodes scapularis Say". Featured Creatures. Photographs by Michael R. Patnaude, web design by Kay Weigel. University of Florida Entomology & Nematology, Institute of Food and Agricultural Sciences. Retrieved 11 April 2024.
- PMID 7799148.
- PMID 9439111.
- PMID 18245258.
- ^ a b c d Thivierge, Karine; Cecan, Alexandra; Saint-Pierre, Dominique; Bertrand, Vicky; Germain, Geneviève (2024). "Detailed description of the Ixodes scapularis, or black-legged tick or deer tick". Institut national de santé publique du Québec. Government du Québec. Retrieved 11 April 2024.
- ^ a b c Thivierge, Karine; Cecan, Alexandra; Saint-Pierre, Dominique; Bertrand, Vicky; Germain, Geneviève (2024). "Other tick species found in Québec". Institut national de santé publique du Québec. Government du Québec. Retrieved 11 April 2024.
- ^ a b Thevanayagam, Sharavanan (2012). Liere, Heidi; Marino, John; OConnor, Barry; Mulcrone, Renee (eds.). "Ixodes scapularis". Animal Diversity Web. Retrieved 11 April 2024.
- ^ a b c Houseman, Richard M. (August 2013). "Ticks and Tick-borne Diseases". MU Extension. Curators of the University of Missouri. Retrieved 11 April 2024.
- ^ Hill, Catherine A.; MacDonald, John F. (August 2013). "THE BIOLOGY AND MEDICAL IMPORTANCE OF TICKS IN INDIANA" (PDF). Purdue Extension Public Health Department of Entomology. Publication ID E-243-W. Retrieved 11 April 2024.
- ^ a b "Westport Weston Health District". 2004. Archived from the original on 2013-09-29. Retrieved 2013-09-26.
- ISBN 978-1-55365-126-0.
- PMID 19008966.
- ^ "Lyme disease graphs | Lyme Disease | CDC". www.cdc.gov. 2017-11-06. Retrieved 2018-05-18.
- ^ "Transmission of Lyme disease | CDC". 29 January 2020.
- ^ McNeil, Donald (19 September 2011). "New Tick-Borne Disease Is Discovered". The New York Times. pp. D6. Retrieved 20 September 2011.
- PMID 11450660.
- PMID 16807416.
- PMID 9452402.
- ^ PMID 25470067.
- ^ Erin Garcia de Jesus (10 December 2020). "How some ticks protect themselves from deadly bacteria on human skin". ScienceNews.
- PMID 31156631.
- ^ Ixodes scapularis genome sequence at VectorBase
External links
- Information on Tick-Related Health Threats and Deer Tick Fact Sheet from the National Pest Management Association
- black-legged tick, Ixodes scapularis on the UF / IFAS Featured Creatures Web site
- Ixodes scapularis, black-legged tick, deer tick overview as a vector for Lyme disease, developmental stages at MetaPathogen
- Ixodes scapularis genome sequence at VectorBase
- Powassan Virus: Transmission on the Centers for Disease Control and Prevention website.