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Arthropod Bites or Stings
Published in Jerome Goddard, Public Health Entomology, 2022
Direct tissue damage from stings or bites may lead to development of skin lesions. Arthropod mouthparts puncture skin in various ways (through a siphoning tube, scissor-like blades, and so on), leading to skin damage; hence damage may be a small punctum, dual puncta (from fangs), or lacerations. However, most lesions result from host immune reactions to salivary secretions or venom. Arthropod saliva is important during feeding in order to lubricate the mouthparts on insertion, increase blood flow to the bite site, inhibit coagulation of host blood, anesthetize the bite site, suppress the host’s immune and inflammatory responses, and aid in digestion. In contrast, venom from certain spiders may directly cause tissue death (necrosis) in human skin. In the United States violin spiders (Figure 20.2D) are primarily responsible for necrotic skin lesions, although sac spiders (Cheiracanthium spp.) and hobo spiders are sometimes reported to cause necrotic arachnidism.17,18 Brown recluse spider venom contains a lipase enzyme, sphingomyelinase D, which is the primary necrotic agent involved in the formation of the typical lesions. Neutrophil chemotaxis may be induced by sphingomyelinase D. The influx of neutrophils into the area contributes to the formation of the necrotic lesion.
Spiders
Published in Gail Miriam Moraru, Jerome Goddard, The Goddard Guide to Arthropods of Medical Importance, Seventh Edition, 2019
Gail Miriam Moraru, Jerome Goddard
It is important to note that at least 50 other species have been implicated in bites on humans. Bites from these species, although painful, generally are not considered as dangerous as the above-mentioned species. Sac spiders in the genus Cheiracanthium can sometimes pose health concerns.2 In Europe, Cheiracanthium punctorium may cause painful burning and swelling at the bite site, while in North America C. inclusum and C. mildei bites may be associated with immediate local pain, erythema, and wheal.3 The famous entomologist WC Reeves carefully documented a bite by C. inclusum wherein he described intense throbbing pain in the local area of the bite, subsiding completely within 12 hours.4 As for other spider groups, Carpenter et al.5 reported on a 15-year-old boy bitten by a plectreurid spider (Plectreurys tristis) in Kern County, California. Initially, the bite produced pain, edema, and slight pallor at the site of the wound, which persisted for 15–30 minutes; subsequently, the patient reported vague, diffuse numbness near the site. All these symptoms resolved within 2 hours. Because not all spider bites are life-threatening or lead to necrotic lesions, it is important for the patient to bring the offending spider into the clinic for identification. This can help physicians avoid the use of expensive treatments used for spider bites from dangerous species. In addition to the direct effects of spider venom, spider bites may produce secondary infections and allergic reactions (apparently rare in the United States).
Poisonous and Venomous Animals - The Physician’s View
Published in Jürg Meier, Julian White, Handbook of: Clinical Toxicology of Animal Venoms and Poisons, 2017
Venom detection is a technique which, although available for more than 20 years, is nevertheless utilised in only a few places worldwide, despite the important information it can provide the clinician. It has been most widely and successfully used in Australia for snakebite7,8, where a commercial snake venom identification kit (Figure 8) can demonstrate the presence of venom and type of antivenom needed from minute samples of venom left at the bite site, giving a result within 20 minutes, and not requiring any laboratory equipment or training. There are many other regions of the world where a variety of snake species are known to cause envenoming, requiring different antivenoms, and a kit such as developed for Australia could prove very useful in such areas. Though not currently commercially available, identification of spider venom and even some marine toxins, such as ciguatoxin, might prove useful at a clinical decision making level.
The role of hydrophobic /hydrophilic balance in the activity of structurally flexible vs. rigid cytolytic polypeptides and analogs developed on their basis
Published in Expert Review of Proteomics, 2018
Peter V. Dubovskii, Roman G. Efremov
Spider venom features the presence of compounds of different complexity with molecular weight from several daltons to few kilodaltons [50]. A substantial portion is represented with disulfide-rich neurotoxins, acting on a variety of calcium, potassium, and sodium channel subtypes. However, some spiders express linear cytolytic peptides (from 20 to 35 residues) without disulfide bridges [51,52]. This is especially valid for ant spider Lachesana tarabaevi [52]. The respective peptides were called Ltc [51]. As many as 12 Ltc were characterized (Figure 1(b), lower panel). Their net positive charge, invoked by the presence of multiple Lys/Arg residues in their sequences varies from + 2 to + 10. The peptide with the lowest charge, Ltc 7, features the presence of multiple Glu-residues, as is typical for some fusion, endosomolytic and pHLIP peptides [53–55].
Black widow spider bite in Johannesburg
Published in Southern African Journal of Infectious Diseases, 2018
Teressa Sumy Thomas, Alan Kemp, Kim Pieton Roberg
Drawn-out symptoms may lead to exhaustion and dehydration, which may have consequences. Treatment of a black widow spider bite includes fluid rehydration, analgesia, relief of muscle cramps and antivenom, when indicated. Anti-tetanus toxoid should be administered. Opioids and benzodiazepines have good anecdotal evidence for the treatment of muscle spasms and may provide effective pain relief,4,6 although some authors advise that caution be exercised if a patient’s respiration is already compromised by symptoms.1 Calcium gluconate, although theoretically thought to decrease the amount of neurotransmitter release in nerve endings that are made more permeable to calcium by the spider venom, has clinically shown to be of short-term benefit only.6
Spider toxins targeting ligand-gated ion channels
Published in Toxin Reviews, 2021
Spider venom includes mixture of compounds ranging in size, structure and function. Despite the fact that we learned a great deal about many of them, there are still looming questions that should be addressed. For example, activity of JSTX-3 and other polyamines on nicotinic receptors is worth investigation. The mode of interaction of PnTx4-5-5 with NMDA receptors is unknown. The factors contributing to the high selectivity of PT1 and PT2 toward P2X3 channels is an interesting question.