what is a tick talk - neha certtick talk: identification of ixodidae (acari) with notes on...

Tick talk:Identification of Ixodidae (Acari) with notes on identification, ecology and phenology.

ByDr. Gerald Fauske

Department of EntomologyNorth Dakota State University

What is a Tick

Image sources (left) Blog‐ Lazy Lizard tales http://lazy‐lizard‐tales.blogspot.com/2009/02/ticked‐off.html ;(right): Iowa State University, Entomology image gallery http://www.ent.iastate.edu/imagegal/ticks/iscap/i‐scap‐m.html

What is a Tick

Image sources: (far right, top bottom) CDC Public Health Library http://phil.cdc.gov/phil/home.asp; (top center right) University of Florida extension http://edis.ifas.ufl.edu/IG140; (lower center right) University of Sao Paulo, Biomedical Sciences http://icb.usp.br/~marcelcp/Default.htm; (left, lower center) University of MI, Barry O’Conor http://insects.ummz.lsa.umich.edu/ACARI/index.html; (top far left) Gary Alpert, Harvard http://www.forestryimages.org/insects.cfm; (left, lower and upper center) Wikipedia http://en.wikipedia.org/wiki/Main_Page

What is a Tick• Phylum Arthropoda: Jointed‐legged animals

Image source: Wikipedia http://en.wikipedia.org/wiki/Main_Page


– Class Arachnida: Arachnids

Image source: Wikipedia http://en.wikipedia.org/wiki/Main_Page


– Class Arachnida: Arachnids• Order Acari: Mites and Tics

At present the are approximately 45,000 described species of Acari placed in about 70 families. This is thought to represent about 5% of the extant species.

Image source: Mites and Ticks, a virtual introduction http://www.sel.barc.usda.gov/acari/index.html; (lower left) University of MI, Barry O’Conor http://insects.ummz.lsa.umich.edu/ACARI/index.html ; (lower center right) NYC Environmental and Forest Biology http://www.esf.edu/efb/faculty/norton.htm.

What is a Tick• Order Acari: Mites & Ticks

– Clade Acariformes• Suborder Trombidiformes

– Prostigmata‐ incl. Velvet mites

• Suborder Sarcoptiformes– Astigmata‐ incl. Mange mites – Oribatida‐ Soil mites

– Clade Opilioaraciformes (Harvestmen‐like mites)

– Clade Parasitiformes• Suborder Mesostigmata‐ incl. Skin mites

• Suborder Holothyrida‐ primitive mites

• Suborder Ixodida‐ Ticks

What is a Tick• Suborder Ixodida

– Family Argasidae: Soft Ticks

– Family Nuttalliellidae: one rare African species.

– Family Ixodidae: Hard Ticks

The approximately 860 species of ticks are placed in 22 genera and three families world wide.

Image source: CDC, emerging infectous diseases http://www.cdc.gov/ncidod/eid/vol8no2/01‐0198‐G1.htm

Tick morphologyIxodidae: Hard ticks

Image source: (left) CDC Public Health Library http://phil.cdc.gov/phil/home.asp ;(right) Gary Alpert USDA http://www.forestryimages.org/insects.cfm

• Scutum present. Mouthparts gnathosoma) visible from above.

Tick morphologyArgasidae: Soft ticks

Image source: (center right) Mat Pound USDA http://www.forestryimages.org/insects.cfm ;(far right) Jim Gathany, (left chart) both CDC Public Health Library http://phil.cdc.gov/phil/home.asp

• Scutum absent.• Mouthparts (gnathosoma) not visible from above.


• Host finding:– Haller’s organ for long distance host detection.

– Four segmentedpalpi for host contact.

Image source: CDC Public Health Library http://phil.cdc.gov/phil/home.asp


• Host finding • Haller’s organ.– Proximal pit: Chemoreceptors.

– Distal pit: Humidity sensor.

Chemoreceptorssensitive to CO2and Butyric acid.

Image source: (left) Gary Alpert, Harvard http://www.forestryimages.org/insects.cfm ;(right) Uncyclopediahttp://uncyclopedia.wikia.com/wiki/Uncyclopedia:Templates/General


• Host findingPalpi.– Apical pit:Mechanoreceptors.Chemoreceptors.

Mechanoreceptors are both heat sensing and tactile. chemoreceptors ‘taste’butyric acid and salts.

Image source: Nation Tick collection via Discover Life http://www.discoverlife.org/mp/20q?search=Ixodes+scapularis


• Hypostome and the feeding process.

Image sources: (right) Science learning network http://www.mos.org/sln/sem/needle.html ;(left) Nation Tick collection via Discover Life http://www.discoverlife.org/mp/20q?search=Ixodes+scapularis


• Feeding process.

Image source: CDC Public Health Library http://phil.cdc.gov/phil/home.asp ; (lower left) Ticks and Lyme disease Vworkers forum http://forums.vwvortex.com/zerothread?cmd=print&id=3873597

Tick life cycle

• Adults

Adults mate on a host and after another blood meal, eggs develop. Female then leaves host for egg deposition.

Individual ticks have been known to survive for as long as 7 years without feeding under laboratory conditions.


Tick life cycle

• Egg: Females lay eggs on soil or at the base of vegetation. A single tick (Ixodidae) may lay as many as 2,000‐ 18,000 eggs. Females of the Argasidae lay from 100‐ 200 eggs. Females die after egg deposition.

Image sources: (top) Cate Hill, Purdue, Stephen Wikel, UCHC http://www.entm.purdue.edu/igp/default.html; (bottom) CDC via Wikimediahttp://commons.wikimedia.org/wiki/File:Argas_spec_columbidae.jpg

Tick life cycle

• Larvae

The six‐legged larva eclosesfrom the egg and ascends vegetation where it waits for a passing host.

Image sources: (top) Vermont Lyme network, Blacklegged tick http://www.vermontlyme.org/ticks.htm; (bottom) Lone star tick larva http://www.visitmonmouth.com/page.aspx?Id=2873

Tick life cycle

• Nymphs

After larvae have taken a blood meal from their host, they moult into the nymphal stage. Some species remain on the host for this process, most leave the host, moult, and then again ascend vegetation and lay in wait for a new host.

Nymphs have eight walking legs but lack the genital plate of adult ticks.

Image source: Penn State University dept of Entomology Image gallery http://www.ento.psu.edu/imagegallery/Ticks‐1.htm

Tick life cycle

• Adults

After Nymphs have fed from their host, they mould into an adult which then has a well developed genital plate and genitalia. As with the previous moult, some species remain on the host for this process, most leave the host, moult, and then again ascend vegetation and lay in wait for a new host.

Image source: CDD

http://www.cdc.gov/ncidod/dvbid/lyme/ld_transmission.htm

Differentiating immature stages from adult ticks

• Necessary for species identification in the family Ixodidae. Larvae: three pairs of walking legs.Nymphs and adults: four pairs of

walking legs.Nymphs without well developed

genital plate, about 1 mm in length.

Adults with well developed genital plate (eggs often visible in female ovaries). Specimens > 1 mm in length.

Note‐ based upon morphological characters, species identification is often not possible with immature stages.


Tick life cycle

• Phenology

– One host tick: larvae, nymphs and adults on a single host.

– Two host tick: larvae and nymphs on one host, adults on a second host.

– Three host tick: each active life stage on a separate host.

Image source: University of Georgia: http://www.vet.uga.edu/vpp/ivm/eng/ticks/biology/feed.htm

Tick life cycleDermacentor variabilis: a 3 host tick

Image source Purdue University, drawing by Scott Charlesworth: http://extension.entm.purdue.edu/eseries3/view.php?article=articles/the_biology_and_medical_importance_of_ticks_in_indiana.txt&id=&section=Medical

Tick life cycleIxodes scapularis: a 3 host tick

Image source CDC: http://www.cdc.gov/ncidod/dvbid/LYME/ld_transmission.htm

Tick Anatomy

Image source: Ticks and Animal disease http://www.vet.uga.edu/vpp/IVM/ENG/ticks/intro.htm

Distinguishing males from females


Tick Identification

Genus Ixodes Non‐Ixodes genera: Dermacentor, Amblyoma, Haemaphysalisand Rhipicephalus

Image sources: (top) Animal and Human Parasite organisms, Gary Upton, University of Kansas http://www.k‐state.edu/parasitology/625tutorials/index.html; (bottom) CDC Public Health Library http://phil.cdc.gov/phil/home.asp

Identification of Tick genera• Ixodes‐ Ixodes scapularis: Black‐legged tick

– Anal groove encirclinganal plate.

– No festoons.

– Basis capitulinot angulate


Ixodidae (Hard ticks)Ixodes

• SpeciesI. angustus NeumannI. banksi BishoppI. brunneus KochI. cookei PackardI. dentatusMarxI. kingi BishoppI. marxi BanksI. muris Bishopp & SmithI. ochotonae GregsonI. scapularis SayI. sculptus NeumannI. spinipalpis Hawden & NuttallI. texanus Banks

• Common name‐‐Skunk tickBird IxodesWoodchuck tickEastern Rabbit tick Rotund tickSquirrel tickMouse tick‐‐Black legged tickGround squirrel tick‐‐Raccoon tick

Ixodes species of the upper Midwest (IA, MI, MN, ND, SD, WI)These 13 species lack festoons. Anal sulcus as a ‘parabolic’ groove around anal plate.

• DistributionIA, MI, MN, ND, SD, WIMI, WIWIIA, MI. MN, SD, WI IA, WIIA, MI, ND, SDMI, MN, ND, WI MI, MN, SD, WISDIA, MN, ND, WIIA, MN, ND, SD, WIND, SDIA, MI, WI

Ixodidae (Hard ticks)Amblyomma, Dermacentor, Haemaphysalis, Rhipicephalus

• SpeciesAmblyomma americanumDermacentor albipictusDermacentor andersoniDermacentor variabilisHaemaphysalis leporuspalustrisRhipicephalus sanguineus

• Common nameLone star tickWinter tickRocky Mountain wood tickAmerican dog tickRabbit tickBrown dog tick

Non‐Ixodes species of the upper Midwest (IA, MI, MN, ND, SD, WI)These species have festoons.

Anal sulcus as a semicircular groove posteriad of anal plate.

• DistributionIA, strays in other states MI, MN, ND, SDND. SDIA, MI. MN, ND, SD, WI IA, MI, MN, ND, SD, WIstrays in all states

Identification of Tick genera

• Amblyomma‐ A. americana: Lone star tick

– Palpi longer than basis capitulum.

Image source Oklahoma State University http://www.ento.okstate.edu/ddd/insects/lonestartick.htm


• Dermacentor‐ D. variabilis: American dog tick

– Palpi and basis capitulumnot angulate.

– Palpi not longer than basis capitulum.

– Opisthosoma withfestoons.

Image source Oklahoma State University http://www.ento.okstate.edu/ddd/insects/lonestartick.htm


• Haemaphysalis‐ H. leporispalustris: Rabbit tick

– 2nd segment of palpusangulate.

Image source: (left) University of Florida, IFAS Extension http://edis.ifas.ufl.edu/topic_fleas_and_ticks(right) CDC Public Health Library http://phil.cdc.gov/phil/home.asp


• Rhipicephalus‐ R. sanguineus: Brown dog tick

– Basis capitulumhexagonal

Image source: (left) University of Florida, IFAS Extension http://edis.ifas.ufl.edu/topic_fleas_and_ticks(right) CDC Public Health Library http://phil.cdc.gov/phil/home.asp

Ticks and disease transmission

• Tick removal.– Using a fine forceps, grasp the capitulum as close to the wound as possible.

– Apply steady upward force until tick is free. Part or all of the hypostome may remain in wound and can be treated as a sliver.

– Do not apply a petroleum product to remove tick.

– Do not squeeze the opisthosoma.

– Do not heat tick with a match.

Image source CDC: http://www.cdc.gov/ncidod/dvbid/Lyme/ld_tickremoval.htm

Summary

• Ticks are Arthropods (Jointed legged animals). Ticks fall within the class Arachnidaand constitute 3 families of Parasitiform Acari. Only Argasidae (soft ticks) and Ixodidae (hard ticks) occur in North America. The hard ticks are the most important with regard to human health.

• The Tick life cycle has four life stages: egg, larva, nymph and adult. Larvae have 6 legs, nymphs and adults have 8 legs. Adults have a well developed genital plate.

• The active stages may be passed on a single host or each stage on a different host. These various associations between active stage and host gives rise to the terms one, two and three host ticks.

• 19 species of Ticks have been recorded from the Upper Midwest. • Ticks are readily identified to genus, even with the immature and often

incomplete specimens submitted for identification. Species identification usually requires complete adult specimens. Identification is often easier with female specimens.

• Because ticks are known disease vectors and individual Ticks may also harbor disease causal organisms for which they are not vectors, proper removal of embedded ticks is important.

Acknowledgements

• This talk has its initial basis in a tick survey of ND ticks conducted by Dr. Don Hyder in 1989‐91. Recent work, Dr. Jeff Vaughn, has added I. scapularis to the ND fauna. Specimen records for the state are from this research and specimens deposited in the North Dakota State Insect Reference Collection (NDSIRC). Sources for images are listed on each slide.

Image sources: (left) http://kirkstarr.vox.com/library/photo/6a00c225264172549d00f48ceedcac0002.html; (right) http://templeofcartoonmojo.blogspot.com/search/label/sketch%20challenge

Useful Literature and references

• Primary literature.– Keirans, J. E. and C. M. Clifford. 1979. The genus Ixodes in the United States: a scanning electron microscope study and key to the adults. Journal of Medical Entomology. Supplement 2. 149 pp.

– Keirans, J. E. and T. R. Litwak. 1989, Pictorial key to the adults of hard ticks, Family Ixodidae(Ixodida: Ixodidae), east of the Mississippi River. Journal of Medical Entomology. 26(5): 435‐ 448.


• Texts.– Evans, G.O. 1992. Principles of Acarology. CAB International,

Cambridge.

– Krantz, G. W. 1978. A manual of Acarology, 2nd ed. Oregon State University Bookstore, Corvalis, OR.

– McDaniel, B. 1979. How to know the mites and ticks. Picture key nature series, Wm. C. Brown Publ. Dubuque, IA.

– van der Hammen, L. 1989. An Introduction to Comparative Arachnology. SPB Academic Publishing, The Hague.


• Web resources:– Tree of Life‐ Acari: http://tolweb.org/Acari– CDC, Tickborne rickettsial diseases: http://www.cdc.gov/ticks/diseases/– University of Lincoln, UK, Tick genus identification key:

http://webpages.lincoln.ac.uk/fruedisueli/FR‐webpages/parasitology/Ticks/TIK/tick‐key/index_lifestage.htm

– Mites and ticks, a virtual introduction: http://www.sel.barc.usda.gov/acari/index.html– Discover Life. Acari‐ Ixodidae:

http://www.discoverlife.org/mp/20q?search=Ixodidae– Ticks and animal diseases: http://www.vet.uga.edu/vpp/IVM/ENG/ticks/intro.htm– Animal and human parasite images: http://www.k‐

state.edu/parasitology/625tutorials/index.html– University of Rhode Island, Tick encounter resource center:

http://www.tickencounter.org/– Oak Ridge national laboratory, Tick identification and prevention:

http://www.esd.ornl.gov/facilities/nerp/Ticks.pdf– Iowa State University, Entomological image gallery, ticks:

http://www.ent.iastate.edu/imagegal/ticks/

what is a tick talk - neha certtick talk: identification of ixodidae (acari) with notes on...

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