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Ticks
Published in Jerome Goddard, Public Health Entomology, 2022
Tick paralysis. Tick paralysis is characterized by an acute, ascending, flaccid motor paralysis that may terminate fatally if the tick is not located and removed. The causative agent is believed to be a salivary toxin produced by ticks when they feed. Many hard tick species may be involved, but Dermacentor andersoni, D. variabilis, and Ixodes holocyclus are notorious offenders. The disease is especially common in Australia. In North America, hundreds of cases have been documented from the Montana–British Columbia region.21,22 Tick paralysis may occur in the southeastern United States as well. The author has seen two documented cases in young children admitted to the University of Mississippi Medical Center in Jackson, MS. Sporadic cases may occur elsewhere, such as Europe, Africa, and South America.
Mite allergens
Published in Richard F. Lockey, Dennis K. Ledford, Allergens and Allergen Immunotherapy, 2020
Enrique Fernández-Caldas, Leonardo Puerta, Luis Caraballo, Victor Iraola, Richard F. Lockey
Ticks (Ixodida), belonging to the families Ixodidae and Argasidae, have several proteins in their saliva that can induce IgE-mediated reactions after a bite. Several cases of anaphylaxis after tick bites are reported [187]. The allergenic composition of these mites has been analyzed [188], and an important allergen of Argas reflexus, the European pigeon tick, is cloned. Arg r 1 is a protein belonging to the lipocalin family [189]. In the case of the paralysis tick, Ixodes holocyclus, an allergen of 28 kDa from the salivary gland, has been identified [190]. Other allergenic proteins, with molecular masses of 51, 38, and 35 kDa from I. pacificus, I. ricinus, Haemaphysalis punctata, and Rhipicephalus sp. are described [191–194].
Clinical Toxicology of Tick Bites
Published in Jürg Meier, Julian White, Handbook of: Clinical Toxicology of Animal Venoms and Poisons, 2017
Most work on the tick neurotoxins has been on the Australian paralysis tick, Ixodes holocyclus. The toxins are difficult to collect in sufficient quantity to characterise. In reviewing this research, Stone1 notes that for this species, the toxin is a pronase resistant protein, produced in the salivary gland (Cell “b” of the granular acinus II), with a MW of about 50 kD, and named Holocyclotoxin. It functions as a presynaptic neurotoxin at the neuromuscular junction. Experimentally, peak production appears to be at about day 5 of the female tick feeding cycle. Studies on the toxin from the North American tick, Dermacentor andersoni, have shown a similar presynaptic neurotoxic action at the NMJ1,2. A list of ticks reported as causing paralysis (in animals) is given in Table 1.
Alpha-gal syndrome: challenges to understanding sensitization and clinical reactions to alpha-gal
Published in Expert Review of Molecular Diagnostics, 2020
José de la Fuente, Alejandro Cabezas-Cruz, Iván Pacheco
Among the co-factors associated to the AGS, several evidence show that exposure to tick bites is an essential risk factor for the development of this syndrome [6]: (i) tick bites elicit an increase in the levels of IgE to α-Gal of 20-fold or greater [2], (ii) most AGS patients have a history of tick bites [26,34,38], (iii) AGS patients have antibodies reactive to tick antigens [2], and (iv) a strong positive correlation between anti-α-Gal IgE and anti-tick IgE levels was reported [2,3]. However, some patients that develop strong allergic reactions to tick bites and have high levels of IgE to α-Gal are mammalian meat tolerant [9]. This finding suggests that mammalian meat allergy is a special type of allergy within a wide spectrum of allergies related to tick bites. AGS has been associated with several tick species including Amblyomma americanum (USA), Amblyomma sculptum (Brazil), Amblyomma testudinarium, and Haemaphysalis longicornis (Japan), Ixodes holocyclus (Australia) and the principal vector of Lyme disease in Europe, Ixodes ricinus [8,39]. Surprisingly, Ixodes scapularis, the main vector of Lyme disease in the USA, which produces α-Gal [40,41] and is closely related to I. ricinus, is almost certainly not a major cause of AGS in the USA [6].