Ticks

Bad Bugs Slideshow

• Ticks Overview
• Ticks Symptoms
• When to Seek Medical Care
• Exams and Tests
• Ticks Treatment
• Self-Care at Home
• Medical Treatment
• Next Steps
• Prevention
• Outlook
• Synonyms and Keywords
• Authors and Editors
• Related Lyme disease article:
  Lyme disease - on WebMD
• Pictures of Bad Bugs - Slideshow

Where Ticks Come From Medical Authors: Barbara K. Hecht, PhD, Frederick Hecht, MD Medical Editor: William C. Shiel Jr., MD, FACP, FACR Ticks carry the bacteria that cause Lyme disease. People contract Lyme disease by being bitten by these ticks. In order to investigate whether specific human behavior increases the risk of tick exposure, researchers from the University of California at Berkeley took to the woods. They found that sitting on a log carried with it the greatest risk of picking up a tick. If you sit on a log (at least in Northern California) for only five minutes, you have a 30% chance of getting a tick on you! Gathering wood was also cited as a risky activity as well as leaning up against a tree. Comment: Aside from issuing a press release (below) about this study, it was also published in the current issue of the Journal of Medical Entomology. In case you aren't familiar with this journal, it is chock-full of everything you might want to know (or not know) about the dangers that mosquitoes, cat fleas, ticks, flies, scorpions, mange mites and other insects pose to you. We don't recommend it for bedtime reading. Read the press release and learn how to avoid ticks »

Ticks Overview

Ticks are the leading carriers of diseases to humans in the United States, second only to mosquitoes worldwide. It is not the tick bite but the toxins or organisms in the tick's saliva transmitted through the bite that cause disease.

Ticks are arthropods, like spiders. There are more than 800 species of ticks throughout the world. They are responsible for carrying such diseases as Rocky Mountain spotted fever, Lyme disease , babesiosis (Texas fever), ehrlichiosis, and tularemia (also transmitted via rabbits), as well as Colorado tick fever and Powassan (a form of encephalitis).

In addition to disease transmission, ticks can also cause tick paralysis. This condition occurs when neurotoxins in the tick saliva make you ill; cause paralysis of the body; and in extreme cases, can stop you from breathing in extreme cases.

Two groups of ticks are important to humans because of the diseases they can transmit:

• Hard ticks have a tough back plate or scutum that defines their appearance. The hard ticks tend to attach and feed for hours to days. Disease transmission usually occurs near the end of a meal, as the tick becomes full of blood. Some of the more common hard ticks are these:
  
  
  • American dog tick
    
    
  • Wood tick
    
    
  • Deer tick (they carry Lyme disease)
    
    
  • Lone star tick
  
  
• Soft ticks have more rounded bodies and do not have the hard scutum found in hard ticks. These ticks usually feed for less than 1 hour. Disease transmission can occur in less than a minute. The bite of some of these ticks produces intensely painful reactions. Two common soft ticks found in the United States are the Pajaroello tick and spinose ear tick.
  
  
• Outbreaks of tick-related illnesses follow seasonal patterns as ticks evolve from larvae to adults. They hide in low brush to hitch a ride on a potential host. Ticks require a "blood meal" to grow and survive, and they are not very particular upon whom or what they feed. If these freeloaders don't find a host, they may die.
  
  
  • Once a tick finds a host—such as you, your pet, a deer, a rabbit—and finds a suitable site for attachment, the tick begins to burrow with its mouthparts into exposed skin. Tick mouthparts are barbed, which helps to secure them to the host.
    
    
  • Often the tick secrets "cementum" to more firmly anchor its mouthparts and head to the host. Ticks may secrete or regurgitate small amounts of saliva that contain neurotoxins. These nerve poisons cleverly prevent you from feeling the pain and irritation of the bite. You may never notice the tick feeding on you. The saliva may contain a blood thinner to make it easier for the tick to get its blood meal.