Tick paralysis: development of a vaccine

Transcriptome and toxin family analysis of the paralysis tick, Ixodes holocyclus

“…Tick saliva mediates the disruption of host defenses through a complex mixture of molecules such as serine protease inhibitors, proteases and lipocalins (Francischetti et al, 2009;Rodriguez-Valle et al, 2010;Ribeiro et al, 2011). Additionally, the saliva of some tick species have venomous characteristics due to the presence of toxins that induce host paralysis (Masina and Broady, 1999;. Stone et al (1989) suggested that paralyzing tick toxins' 'most likely primary function is as a feeding stimulant, with toxicity as a secondary, probably accidental, additional function'.…”

“…It has been reported that 69 tick species from a total of 892 described species are associated with tick paralysis, and most are members of the Ixodidae (hard ticks) while only nine are members of the Argasidae (soft ticks). The most economically significant of these tick species for animal and human health are Dermacentor andersoni and Dermacentor variabilis in North America; Ixodes rubicundus, Rhipicephalus evertsi evertsi and Argas (Persicargas) walkerae in Africa; and Ixodes holocyclus (the Australian paralysis tick) in Australia (Masina and Broady, 1999;.…”

“…Three neurotoxins (HTs) with molecular weights of approximately 5 kDa, named HT1, HT2 and HT3, were identified by isolating the proteins bound to rat synaptosomes, and a partial protein and full-length DNA sequence for HT1 was reported (Thurn, 1992). Other studies attempted to produce a recombinant variant of HT1, which exhibited immunogenic properties against toxin present in salivary gland (SG) extracts of I. holocyclus but no protection from paralysis symptoms in immunized animals (Masina and Broady, 1999;HallMendelin et al, 2011). Twenty-one nucleotide sequences related to HTs were recently submitted to GenBank (https://www.ncbi.nlm.nih.gov/pubmed/23193287) and were linked to a patent application by Zoetis, Australia (WO 2014018724 A1).…”

Tick paralysis in Australia caused byIxodes holocyclusNeumann

“…Subsequently, HT-1 was isolated and defined by N-terminal amino-acid sequencing (Thurn, 1994). The corresponding gene, which was isolated, sequenced and characterised by Masina and Broady (1999), showed a high homology with the gene coding scorpion neurotoxin.…”

Tick Paralysis of a Snake Caused by Amblyomma rotundatum (Acari: Ixodidae)

“…Tick paralysis is caused by a salivary neurotoxin secreted by one or more ticks during prolonged feeding on a host, and it can cause motor impairment and even death of the host (Masina andBroady 1999, Mans et al 2004). Signs of paralysis usually improve within hours of tick removal and may completely reverse, depending on the duration of attachment and individual host response (Gothe 1984).…”