Ticks saliva

Ticks have a bad reputation for good reasons. Not only are they carriers of a number of diseases, the saliva of some can cause paralysis. North American natives were aware of tick paralysis, but the condition was officially noted as a disease of both animals and humans in 1912. The bites of at least 60 species of ticks can cause paralysis, which often does not appear until several days after the bite. The first indication is redness and swelling around the site of the bite. This is followed by neuromuscular weakness and difficulty in walking. If the tick is not removed, speech and breathing are affected, with eventual respiratory paralysis and death. Fortunately, removal of the tick results in a quick recovery of function. The exact mechanism of paralysis is not known but it appears to come from a substance that affects the neuromuscular junction. While not related to the venom of the tick saliva, the tick can also transmit diseases such as Lyme disease, Rocky Mountain spotted fever, Q fever, typhus, and others. Table 13.1 lists some venomous arachnids. 

Infective metacyclic sporozoites in tick saliva are passed directly into the host, where they immediately enter erythrocytes and begin to undergo... 

Interaction of Tick Saliva with the Mammalian Host... 

Valenzuela JG. Exploring tick saliva from biochemistry to sialomes and functional genomics. Parasitology 2004 129 S83-S94. 

Juncadella IJ, Garg R, Ananthanarayanan SK et al. T-cell signaling pathways inhibited by the tick saliva immunosuppressor, salplS. FEMS Immunol Med Microbiol 2007 49(3) 433-438. 

Genes encoding putative metalloproteases are present in the salivary glands of/, scapularis 50). Tick saliva metalloproteases would provide another means of preventing platelet aggregation, hi addition, the disruption of extracellular matrix likely contributes to maintaining the feeding lesion around tick mouthparts. 

Arbovirus transmission is enhanced by mosquito saliva. Cache Valley virus introduced into feeding sites of Aedes aegypti, Aedes triseriatus, or Culex pipiens enhances infection (108). Likewise, saliva of A. triseriatus potentiates vesicular stomatitis virus transmission (109). Tick saliva facilitates transmission of Thogoto virus (110), tick-borne encephalitis virus (111), vesicular stomatitis virus (112), Theileria parva (113), and Francisella tularensis (114). 

Ticks Bite - saliva neurotoxin - transmit other diseases Tick paralysis - weakness and difficulty walking -remove tick... 

These cxamfdes provide evidence of co-evolutionary mechanisms that result in the maintenance of a beneficial relationship between ticks and pathogens. However, while the presence oftick saliva proteins that are beneficial for the completion of the infectious cycle ofthese micro-organisms has been described, no infi>rmation is available chat provides evidence of advantages provided to the vector by the presence of the micro-organism. Thus, the relationship between both may be merely of a parasitic nature, although it is possible that unknown mechanisms would reside in advants es CO the tick due to the presence of these bacteria. Further research should clarify this point. 

Ferreira BR, Silva JS. Saliva of Rhipicephalus sanguineus tick impairs T-cell proliferation and IFN-gamma-induced macrophage microbicidal activity. Vet Immunol Immunopathol 1998 64(3) 279-293. 

Insects are not the only organisms to express serpins that allow these organisms to invade their hosts and evade the host inflammatory responses. Helminthes, such as Schistosomes and Brugia express serpins that dampen the immune responses of their hosts in not one, but several pathways. " In blood feeding, ticks also secrete serpins in their saliva to inhibit the local inflammatory response and blood clotting to prolong their ability to feed without detection. ... 

Prevot PP, Adam B, udjcltia KZ et aL Anti-hemostatic effects of a serpin from the saliva of the tick ixodes ricinus. J Biol Chem 2006 281(36) 26361-26369. 

Tick paralysis A disease characterized by fever and paralysis due to anticoagulants and toxins secreted into a tick s bite via the ectoparasite s saliva. 

Tick-borne encephalitis (TBE) is found as a broad band from Europe to Siberia and is also present in Japan and parts of Asia. In Europe, Austria has one of the highest incidences. Those expecting to be trekking and walking in forested areas of endemic countries are often advised to receive the TBE vaccine. The virus in the saliva of the tick multiples rapidly during feeding so early removal of the tick would not be of great benefit. 

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