Clinical Toxicology of Tick Bites
Jürg Meier, Julian White in Handbook of: Clinical Toxicology of Animal Venoms and Poisons, 2017
Ticks are invertebrates, members of the class Arachnida, subclass Acari, order Meostigmata. They have 4 pairs of walking legs and no antennae, a feeding device (hypostoma) and are all ectoparasites of terrestrial vertebrates, particularly mammals. Ticks of medical importance are found in two distinct families; Ixodidae (hard ticks) and Argasidae (soft ticks). The Ixodid ticks are in the majority (at least 644 species2). They have a hard body plate, or cuticle, unlike the Argasid ticks (at least 149 species2), the cuticle of which is not rigid, and “leathery”. Argasid ticks feed, then drop off the host, the feeding process often taking only 5 to 25 mins. In contrast, Ixodid ticks in the adult phase (females) may remain attached to the host, feeding, for a considerably longer period of time, up to 11 days, possibly more. In general, it appears that the longer the period of attachment, the more likely is paralysis. Tick paralysis is a phenomenon associated with Ixodid ticks, and the following description of feeding biology relates to this group.
Comparative aspects of the tick–host relationship: immunobiology, genomics and proteomics
G. F. Wiegertjes, G. Flik in Host-Parasite Interactions, 2004
Ticks are obligate haematophagous ectoparasites that belong to the Class Arachnida, a group of arthropods including mites and spiders that are able to infest a wide variety of vertebrate hosts in most habitats of the world (Klompen et al., 1996; Sonenshine, 1991). Ticks are generally classified into three major families: the Ixodidae or ‘hard ticks’, the Argasidae or ‘soft ticks’, and the Nuttalliellidae comprised of a single species. Argasid ticks, characterized by the absence of a dorsal cuticular shield (scutum) (Figure 1), are generally represented by the genus Ornithodoros which includes species of medical importance such as Ornithodoros moubata found in the African continent, and Ornithodoros hermsii, common in the western United States. Argasids are normally found in the immediate vicinity of their hosts (endophilic) and are known for their ability to resist desiccation and starvation. Developmental stages of soft ticks may include several nymphal stages, and characteristically both nymphs and adults feed frequently for short periods of time (Anderson, 2002; Parola and Raoult, 2001).
Mite Allergens
Richard F. Lockey, Dennis K. Ledford in Allergens and Allergen Immunotherapy, 2014
Several parasitic mite species are in frequent contact with humans and domestic animals. The itch mite Sarcoptes scabiei causes skin lesions and IgE-mediated sensitization in parasitized individuals [143–145]. Allergens homologous to serine proteases (group 3), GSTs (group 8), paramyosin (group 11), tropomyosin, and apolipoprotein have been identified [146–150]. Ticks (Ixodida) belonging to families Ixodidae and Argasidae have several proteins in their saliva that can induce IgE-mediated reactions after biting. Several cases of anaphylaxis after tick bites are reported [151]. The allergenic composition of these mites has been analyzed [152], and an important allergen of Argas reflexus, the European pigeon tick, is cloned. Arg r 1 is a protein belonging to the lipocalin family [153]. In the case of the paralysis tick, Ixodes holocyclus, an allergen of 28 kDa from the salivary gland has been identified [154]. Other allergenic proteins, with molecular masses of 51, 38, and 35 kDa from I. pacificus, I. ricinus, Haemaphysalis punctata, and Rhipicephalus sp., are described [155–158].
Laboratory diagnosis of Lyme borreliosis: Current state of the art and future perspectives
Published in Critical Reviews in Clinical Laboratory Sciences, 2018
Benedikt Lohr, Volker Fingerle, Douglas E. Norris, Klaus-Peter Hunfeld
The natural reservoir of LB agents is primarily small rodents, but a variety of other small- to medium-sized wild and domestic animals may also serve as reservoirs [2]. The bacteria are transmitted by members of the Ixodes (I.) ricinus complex, predominantly I. ricinus and I. persulcatus in Europe and Asia, and I. scapularis and I. pacificus in North America [4,9]. Once infected with borreliae, these three-host hard-bodied ticks (Ixodidae) retain the infection for the remainder of their lives, including through molts, thereby effectively transmitting spirochetes to the next feeding stage and potentially to their hosts [10]. The geographical presence of the disease follows a belt-like distribution and mirrors the distribution of ixodes ticks that transmit LB agents in the Northern Hemisphere (Figure 1).
Post-exposure prophylactic vaccine candidates for the treatment of human Risk Group 4 pathogen infections
Published in Expert Review of Vaccines, 2020
James Logue, Ian Crozier, Peter B Jahrling, Jens H Kuhn
Finally, tick-borne encephalitis virus (TBEV; Flaviviridae: Flavivirus) is generally transmitted by ixodid ticks in Western (Ixodes ricinus) and Eastern (Ixodes persulcatus) Europe. The virus is maintained by over 100 species of wild animals, including voles, deer, and domestic animals such as sheep [122–124]. Although patients infected with TBEV normally only present with an initial, nonspecific febrile phase, 20–30% of patients progress to a second stage of disease with CNS signs (meningitis, encephalitis, or both). Lethality is generally 1–2%, but 30–60% of patients develop chronic neuropsychiatric sequelae [125,126]. Three different vaccines for pre-exposure disease prevention (IPVE, FSME-IMMUN, and Encepur) are generally available in endemic regions [127]. However, fears over the potential of antibody-dependent disease enhancement or increased viral infectivity caused by ‘sub-optimal’ concentrations of virus-specific antibodies have hampered further vaccine development [128]. For this reason and the potential of other adverse effects [129], none of these vaccines are licensed by the US FDA. Vaccine use is neither recommended by the US Centers for Disease Control and Prevention (CDC) nor the WHO except for high-risk individuals, such as laboratory workers or workers with high exposure to potentially infected host ticks [130,131]. Multiple studies into the use of antibody treatments as PEP have produced promising results in laboratory mice with no disease enhancement [132,133].
Additional considerations for anti-tick vaccine research
Published in Expert Review of Vaccines, 2022
José de la Fuente, Marinela Contreras
Recent publications and particularly a recent paper by Ndawula, Jr [1]. provided a comprehensive review on anti-tick vaccine research and results. In this review, the author addressed the limitations in tick vaccine research with emphasis on the methodology for the evaluation of vaccine efficacy and effectiveness and the need to advance in the characterization of the immunological mechanisms mediating vaccine efficacy for the control of both ixodid and argasid tick infestations. We agree on this proposal for the evaluation of vaccine efficacy and effectiveness. However, additional considerations disclosed here using our research based on the Subolesin tick antigen model are relevant for the development of effective and safe vaccines for the control of tick infestations and tick-borne diseases (TBD).
Related Knowledge Centers
- Argasidae
- Borrelia
- Dermacentor
- Moulting
- Mouth
- Rickettsia
- Tick
- Scute
- Disease Vector
- Biological Life Cycle