<unk>  is believed to be due to toxins found in the<unk> 's saliva that enter the bloodstream while the<unk>  is feeding. The two<unk> s most commonly associated with North American<unk>  are the Rocky Mountain wood<unk>  (Dermacentor andersoni) and the American dog<unk>  (Dermacentor variabilis); however, 43<unk>  species have been implicated in human disease around the world. Most North American cases of<unk>  occur from April to June, when adult Dermacentor<unk> s emerge from hibernation and actively seek hosts. In Australia,<unk>  is caused by the<unk>  Ixodes holocyclus. Prior to 1989, 20 fatal cases were reported in Australia. Although<unk>  is of concern in domestic animals and livestock in the United States as well, human cases are rare and usually occur in children under the age of 10.<unk>  occurs when an engorged and gravid (egg-laden) female<unk>  produces a neurotoxin in its salivary glands and transmits it to its host during feeding. Experiments have indicated that the greatest amount of toxin is produced between the fifth and seventh day of attachment (often initiating or increasing the severity of symptoms), although the timing may vary depending on the species of<unk> . Unlike Lyme disease, ehrlichiosis, and babesiosis, which are caused by the systemic proliferation and expansion of parasites in their hosts long after the offending<unk>  is gone,<unk>  is chemically induced by the<unk>  and therefore usually only continues in its presence. Once the<unk>  is removed, symptoms usually diminish rapidly. However, in some cases, profound paralysis can develop and even become fatal before anyone becomes aware of a<unk> 's presence.
Tick paralysis
Monoplegia
Flaccid paralysis
Pyramidal signs
Hard flaccid syndrome
Periodic paralysis
Klumpke paralysis
Multi/minicore myopathy