Venomous ticks??

Image of a tick from: www2.outdoorchannel.comScience Blogs – by Dr. Doolittle

Ticks are blood-sucking arthropods that can act as vectors for various diseases in both animals and humans. A recent article published in Frontiers in Zoology summarizes findings that suggest ticks may also be considered venomous ectoparasites. For example, Ixodes holocyclus is a species of Australian tick whose saliva can induce paralysis in humans and animals. According to the new article, about 8% of known tick species can induce paralysis. Ornithodoros savignyi ticks even secrete a lethal salivary toxin (for mice at least). Several proteins from venomous families have been identified in tick saliva such as:  

  • Kunitz peptides: target ion channels and inhibition of enzymes that degrade proteins, aka proteases
  • Cystatins: another protease inhibitor
  • Defensins: small proteins that in ticks act as antimicrobial proteins and in some species can break down red blood cells
  • Lipocalins: cardiovascular effects and blood clot inhibition
  • Phospholipase A2: function in  ticks unclear, may help with prolonged feeding
  • Lectins: tick lectin shown to suppress the immune system of mice

Based on these components of tick saliva, the study authors argue that ticks should be considered venomous ectoparasites.

Source:

Cabezas-Cruz A and Valdés JJ. Are ticks venomous animals? Frontiers in Zoology. 11:47, 2014. doi:10.1186/1742-9994-11-47

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http://scienceblogs.com/lifelines/2014/07/06/venomous-ticks/

8 thoughts on “Venomous ticks??

  1. This one caught my attention due to the thread we had going the other day on ticks and chiggers.

    Had no idea that some are capable of paralyzing a human.

    1. Dumping a planeload on Congress (while in session), the White House, and the Pentagon simultaneously comes to mind.

        1. Angel and #1, I just went through the most fast acting, virulent strain of Lyme’s disease I’ve ever had. Incubation period usually is a week or better. I was sick as a dog in 3 days and this tick was not on my arm even close to 24 hours. It’s not normal, they must have introduced a deadlier strain. I shutter to think about how sick I would have been had I not started the antibiotics right away.

  2. “Science Blogs – by Dr. Doolittle” …..really? To funny, wish the fine Dr. could give me some tips on freaking fly’s!

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