Description
Ticks are in the phylum of animals called Arthropoda (jointed appendage). This phylum of animals is the largest in the animal kingdom. There are over 850 different species of ticks, and they parasitize every class of terrestrial vertebrate animal, including amphibians.Ticks are small rounded arachnids that cling to one spot and do not move. They have inserted their head under the skin and are engorging themselves on the blood. Diseases carried by ticks means that you should have yourself or your pets checked after you find ticks. On the one hand, ticks are a little easier to deal with since they remain outdoors, and do not infest houses the way fleas do on the other hand, they carry more dangerous diseases and are harder to find.
Role in diseases
Ticks are the most important arthropod in transmitting diseases to domestic animals and run a close second to mosquitoes in arthropod borne human diseases. They transmit a greater variety of infectious agents than any other type of arthropod. Ticks can cause disease and illness directly. They are responsible for anemia due to blood loss, dermatosis due to salivary secretions, and ascending tick paralysis due to neurotoxins in the salivary secretions. They also can be the vector of other diseases. Some of the more noted tick borne diseases are babesiosis, anaplasmosis, ehrlichia, East Coast fever, relapsing fever, rocky mountain spotted fever and, of course, Lyme disease.Kinds of ticks
There are two basic types of ticks. Soft ticks, the argasids, are distinguished by their soft, leathery cuticle and lack of scutum. They can be recognized easily by their subterminal mouthparts that are on the underside of the tick. Soft ticks when engorged with blood blow up like a balloon. Soft ticks are fast feeders, being able to tank up in a matter of hours.Hard ticks, the Ixodids, have a hard plate on the dorsal surface and have terminal mouthparts. When attaching, a tick will slice open the skin with the mouthparts and then attach itself. They also secrete a cement that hardens and holds the tick onto the host. Hard ticks are slow feeders, taking several days to finish their bloodmeal.
During feeding a tick may extract up to 8 ml of blood, they can take 100X their body weight in blood. Interestingly, they concentrate the blood during feeding and will return much of the water to the host while losing some by transpiration through the cuticle.