Experimental Assays to Assess the Efficacy of Vinegar and Other Topical First-Aid Approaches on Cubozoan (Alatina alata) Tentacle Firing and Venom Toxicity

Clinical Management of North American Snake and Marine Envenomations

Envenomations are the 23rd most common reason for calls to US poison control centers, with over 35,000 incidents reported annually. Snake bites account for over 20% of those calls, while marine envenomations are likely underreported at 3% to 4%.1 While these types of envenomations may not be encountered on a daily basis for many physicians, the different types of envenomations warrant unique management strategies based on the offending creature and symptom presentation. This text serves as a review of the epidemiology, clinical presentations, and management of endemic North American species of snakes and marine vertebrate and invertebrate envenomations.

Jellyfish Stings: A Review of Skin Symptoms, Pathophysiology, and Management

With the surge in the human coastal population and the increasing frequency of human activities along the coast, cases of marine envenomation, particularly jellyfish envenomation, have notably risen. Jellyfish stings can induce a spectrum of symptoms that vary in severity, encompassing skin injuries, acute systemic venom effects, delayed indirect sequelae, and even fatality, causing significant distress to patients. Among these manifestations, the occurrence of skin lesions following jellyfish stings is prevalent and substantial. These lesions are characterized by evident blister formation, development of bullae, subcutaneous hemorrhage, erythema, papules, wheal, ecchymosis, and ulceration or skin necrosis. Local cutaneous manifestations may persist for several weeks or even months after the initial sting. Despite aggressive treatment, many skin injuries still result in significant pigmentation or scarring after recovery. To address this issue effectively, it is imperative to conduct comprehensive evidence-based medical research, elucidate various components within jellyfish venom, and elucidate its pathogenic mechanism to develop targeted treatment programs. This article aims to review the skin symptoms, pathophysiology, and management of jellyfish stings. Such considerations can provide comprehensive guidance to medical professionals and the public and minimize the harm caused by jellyfish stings.

Effect of Rinse Solutions on Rhizostoma pulmo (Cnidaria: Scyphozoa) Stings and the Ineffective Role of Vinegar in Scyphozoan Jellyfish Species

Rhizostoma pulmo is a widely distributed scyphozoan in the Mediterranean Sea. Their stings result mainly in erythema, small vesicles, or/and pain, and cause a high number of bathers to seek assistance from first-aid services during the summer season. Despite the threat that jellyfish stings represent to public health, there is disagreement in the scientific community on first-aid protocols, with the dispute largely centered around the effectiveness of vinegar. In the present research, we investigated the effect of commonly used rinse solutions on nematocyst discharge in R. pulmo and the effect of vinegar on three more scyphozoans (Aurelia sp., Cassiopea sp., and Rhizostoma luteum). Scented ammonia, vinegar, and acetic acid triggered nematocyst discharge in R. pulmo. Vinegar also caused nematocyst discharge in Aurelia sp., Cassiopea sp., and R. luteum. In contrast, seawater, baking soda, freshwater, urine, and hydrogen peroxide were considered neutral solutions that did not induce nematocyst discharge. These results indicate that the use of vinegar, acetic acid, or commercial products based on these compounds is counterproductive. Their use can worsen pain and discomfort caused not only by R. pulmo stings but also by those of any scyphozoan. The use of seawater is recommended for cleaning the R. pulmo sting site until an inhibitor solution that irreversibly prevents nematocyst discharge is discovered.

Inhibition of Nematocyst Discharge from Pelagia noctiluca (Cnidaria: Scyphozoa)—Prevention Measures against Jellyfish Stings

Pelagia noctiluca stings are common in Mediterranean coastal areas and, although the venom is non-lethal, they are painful. Due to its high toxicity and abundance, P. noctiluca is considered a target species for the focus of research on active ingredients to reduce the symptoms of its sting. To determine the effect of 31 substances and formulations on nematocyst discharge, we performed three tests: (1) screening of per se discharge activator solutions, (2) inhibitory test with nematocyst chemical stimulation (5% acetic acid) and (3) inhibitory test quantifying the hemolytic area. Ammonia, barium chloride, bleach, scented ammonia, carbonated cola, lemon juice, sodium chloride and papain triggered nematocyst discharge. All of them were ruled out as potential inhibitors. Butylene glycol showed a reduction in nematocyst discharge, while the formulations of 10% lidocaine in ethanol, 1.5% hydroxyacetophenone in distilled water + butylene glycol, and 3% Symsitive® in butylene glycol inhibited nematocyst discharge. These last results were subsequently correlated with a significant decrease in hemolytic area in the venom assays versus seawater, a neutral solution. The presented data represent a first step in research to develop preventive products for jellyfish stings while at the same time attempting to clarify some uncertainties about the role of various topical solutions in P. noctiluca first-aid protocols.

Raising Awareness on the Clinical and Forensic Aspects of Jellyfish Stings: A Worldwide Increasing Threat

Jellyfish are ubiquitous animals registering a high and increasing number of contacts with humans in coastal areas. These encounters result in a multitude of symptoms, ranging from mild erythema to death. This work aims to review the state-of-the-art regarding pathophysiology, diagnosis, treatment, and relevant clinical and forensic aspects of jellyfish stings. There are three major classes of jellyfish, causing various clinical scenarios. Most envenomations result in an erythematous lesion with morphological characteristics that may help identify the class of jellyfish responsible. In rare cases, the sting may result in delayed, persistent, or systemic symptoms. Lethal encounters have been described, but most of those cases happened in the Indo-Pacific region, where cubozoans, the deadliest jellyfish class, can be found. The diagnosis is mostly clinical but can be aided by dermoscopy, skin scrapings/sticky tape, confocal reflectance microscopy, immunological essays, among others. Treatment is currently based on preventing further envenomation, inactivating the venom, and alleviating local and systemic symptoms. However, the strategy used to achieve these effects remains under debate. Only one antivenom is currently used and covers merely one species (Chironex fleckeri). Other antivenoms have been produced experimentally but were not tested on human envenomation settings. The increased number of cases, especially due to climate changes, justifies further research in the study of clinical aspects of jellyfish envenoming.

Trial Assay for Safe First-Aid Protocol for the Stinging Sea Anemone Anemonia viridis (Cnidaria: Anthozoa) and a Severe Toxic Reaction

Anemonia viridis is an abundant and widely distributed temperate sea anemone that can form dense congregations of individuals. Despite the potential severity of its sting, few detailed cases have been reported. We report a case of a severe toxic reaction following an A. viridis sting in a 35-year-old oceanographer. She developed severe pain, itching, redness, and burning sensation, which worsened one week after treatment with anti-inflammatories, antihistamines and corticosteroids. Prompted by this event, and due to the insufficient risk prevention, lack of training for marine-environment users, and lack of research into sting-specific first-aid protocols, we evaluated the cnidocyst response to five different compounds commonly recommended as rinse solutions in first-aid protocols (seawater, vinegar, ammonia, baking soda, and freshwater) by means of the Tentacle Solution Assay. Vinegar and ammonia triggered an immediate and massive cnidocyst discharge after their application and were classified as activator solutions. Baking soda and freshwater were also classified as activator solutions, although with a lower intensity of discharge. Only seawater was classified as a neutral solution and therefore recommended as a rinse solution after A. viridis sting, at least until an inhibitory solution is discovered.

Differing Effects of Vinegar on Pelagia noctiluca (Cnidaria: Scyphozoa) and Carybdea marsupialis (Cnidaria: Cubozoa) Stings-Implications for First Aid Protocols

The jellyfish species that inhabit the Mediterranean coastal waters are not lethal, but their stings can cause severe pain and systemic effects that pose a health risk to humans. Despite the frequent occurrence of jellyfish stings, currently no consensus exists among the scientific community regarding the most appropriate first-aid protocol. Over the years, several different rinse solutions have been proposed. Vinegar, or acetic acid, is one of the most established of these solutions, with efficacy data published. We investigated the effect of vinegar and seawater on the nematocyst discharge process in two species representative of the Mediterranean region: Pelagia noctiluca (Scyphozoa) and Carybdea marsupialis (Cubozoa), by means of (1) direct observation of nematocyst discharge on light microscopy (tentacle solution assay) and (2) quantification of hemolytic area (tentacle skin blood agarose assay). In both species, nematocyst discharge was not stimulated by seawater, which was classified as a neutral solution. In P. noctiluca, vinegar produced nematocyst discharge per se, but inhibited nematocyst discharge from C. marsupialis. These results suggest that the use of vinegar cannot be universally recommended. Whereas in case of a cubozoan C. marsupialis sting, the inhibitory effect of vinegar makes it the ideal rinse solution, in case of a scyphozoan P. noctiluca sting, vinegar application may be counterproductive, worsening the pain and discomfort of the stung area.

Field Experiment Effect on Citrus Spider Mite Panonychus citri of Venom from Jellyfish Nemopilema nomurai: The Potential Use of Jellyfish in Agriculture

Jellyfish are rich in resources and widely distributed along coastal areas. As a potential approach to respond to jellyfish blooms, the use of jellyfish-derived products is increasing. The citrus spider mite (Panonychus citri) is one of the key citrus pests, negatively impacting the quality and quantity of oranges. Due to the resistance and residue of chemical acaricides, it is important to seek natural substitutes that are environmentally friendly. The field efficacy of the venom from the jellyfish Nemopilema nomurai against P. citri was assayed in a citrus garden. The frozen N. nomurai tentacles were sonicated in different buffers to isolate the venom. The venom isolated by PBS buffer (10 mM, pH 6.0) had the strongest acaricidal activity of the four samples, and the corrected field efficacy 7 days after treatment was up to 95.21%. This study demonstrated that jellyfish has potential use in agriculture.

Preparation and Neutralization Efficacy of Novel Jellyfish Antivenoms against Cyanea nozakii Toxins

Jellyfish stings are a common issue globally, particularly in coastal areas in the summer. Victims can suffer pain, itching, swelling, shock, and even death. Usually, hot water, vinegar, or alumen is used to treat the normal symptoms of a jellyfish sting. However, a specific antivenom may be an effective treatment to deal with severe jellyfish stings. Cyanea nozakii often reach a diameter of 60 cm and are responsible for hundreds of thousands of stings per year in coastal Chinese waters. However, there has been no specific C. nozakii antivenom until now, and so the development of this antivenom is very important. Herein, we collected C. nozakii antisera from tentacle extract venom immunized rabbits and purified the immunoglobulin (IgG) fraction antivenom (AntiCnTXs). Subsequently, two complete procedures to produce a refined F(ab')₂ type of antivenom (F(ab')₂-AntiCnTXs) and Fab type of antivenom (Fab-AntiCnTXs) by multiple optimizations and purification were established. The neutralization efficacy of these three types of antivenoms was compared and analyzed in vitro and in vivo, and the results showed that all types of antibodies displayed some neutralization effect on the lethality of C. nozakii venom toxins, with the neutralization efficacy as follows: F(ab')₂-AntiCnTXs ≥ AntiCnTXs > Fab-AntiCnTXs. This study describes the preparation of novel C. nozakii jellyfish antivenom preparations towards the goal of developing a new, effective treatment for jellyfish stings.

Protective effect of epigallocatechin-3-gallate (EGCG) on toxic metalloproteinases-mediated skin damage induced by Scyphozoan jellyfish envenomation

Jellyfish stingings are currently raising serious public health concerns around the world. Hence, the search for an effective first aid reagent for the envenomation has been the goal of many investigators in the field. There have been a few previous reports of in vivo as well as in vivo studies suggesting the metalloproteinase activity of scyphozoan jellyfish venom, such as N. nomurai venom (NnV), plays a major role in the pathogenesis. These results have inspired us to develop a metalloproteinase inhibitor as a candidate for the treatment of Scyphozoan jellyfish envenomation. It has been previously demonstrated that the major polyphenol component in green tea, epigallocatechin-3-gallate (EGCG), can inhibit metalloproteinase activity of snake venoms. In fact, plant polyphenols as potential therapeutics have been shown to exert positive effects on neutralizing snake venoms and toxins. In the present study, we found that EGCG significantly inhibits the toxic proteases of NnV in a concentration-dependent manner. Human keratinocyte (HaCaT) and Human dermal fibroblast (HDF) cell culture studies showed that EGCG treatment can protect the cells from NnV-induced cytotoxicity which has been accompanied by the down-regulation of human matrix metalloproteinase (MMP)-2 and -9. Simulated rat NnV envenomation study disclosed that topical treatments with EGCG considerably ameliorated the progression of the dermonecrotic lesions caused by NnV. EGCG also reduced the activitions of tissue MMP-2 and MMP-9, which seem to be crucial players in the dermal toxic responses induced by NnV. Therefore, we propose that EGCG might be an effective therapeutic agent for the treatment of cutaneoous jellyfish symptoms.

Impact of Scyphozoan Venoms on Human Health and Current First Aid Options for Stings

Cnidaria include the most venomous animals of the world. Among Cnidaria, Scyphozoa (true jellyfish) are ubiquitous, abundant, and often come into accidental contact with humans and, therefore, represent a threat for public health and safety. The venom of Scyphozoa is a complex mixture of bioactive substances—including thermolabile enzymes such as phospholipases, metalloproteinases, and, possibly, pore-forming proteins—and is only partially characterized. Scyphozoan stings may lead to local and systemic reactions via toxic and immunological mechanisms; some of these reactions may represent a medical emergency. However, the adoption of safe and efficacious first aid measures for jellyfish stings is hampered by the diffusion of folk remedies, anecdotal reports, and lack of consensus in the scientific literature. Species-specific differences may hinder the identification of treatments that work for all stings. However, rinsing the sting site with vinegar (5% acetic acid) and the application of heat (hot pack/immersion in hot water) or lidocaine appear to be substantiated by evidence. Controlled clinical trials or reliable models of envenomation are warranted to confirm the efficacy and safety of these approaches and identify possible species-specific exceptions. Knowledge of the precise composition of Scyphozoa venom may open the way to molecule-oriented therapies in the future.

Cnidarian Jellyfish: Ecological Aspects, Nematocyst Isolation, and Treatment Methods of Sting

Cnidarians play an important role in ecosystem functioning, in the competition among species, and for possible utilization of several active compounds against cardiovascular, nervous, endocrine, immune, infective, and inflammatory disorders or having antitumoral properties, which have been extracted from these organisms. Nevertheless, notwithstanding these promising features, the main reason for which cnidarians are known is due to their venomousness as they have a serious impact on public health as well as in economy being able to affect some human activities. For this reason a preeminent subject of the research about cnidarians is the organization of proper systems and methods of care and treatment of stinging. This chapter aims to present the data about the morphological, ecological, toxicological, epidemiological, and therapeutic aspects regarding cnidarians with the purpose to summarize the existing knowledge and to stimulate future perspectives in the research on these organisms.

Evaluation of Cyanea capillata Sting Management Protocols Using Ex Vivo and In Vitro Envenomation Models

Lion's mane jellyfish (Cyanea capillata) stings cause severe pain and can lead to dangerous systemic effects, including Irukandji-like syndrome. As is the case for most cnidarian stings, recommended medical protocols in response to such stings lack rigorous scientific support. In this study, we sought to evaluate potential first aid care protocols using previously described envenomation models that allow for direct measurements of venom activity. We found that seawater rinsing, the most commonly recommended method of tentacle removal for this species, induced significant increases in venom delivery, while rinsing with vinegar or Sting No More® Spray did not. Post-sting temperature treatments affected sting severity, with 40 min of hot-pack treatment reducing lysis of sheep's blood (in agar plates), a direct representation of venom load, by over 90%. Ice pack treatment had no effect on sting severity. These results indicate that sting management protocols for Cyanea need to be revised immediately to discontinue rinsing with seawater and include the use of heat treatment.

Assessing the Efficacy of First-Aid Measures in Physalia sp. Envenomation, Using Solution- and Blood Agarose-Based Models

Stings from the hydrozoan species in the genus Physalia cause intense, immediate skin pain and elicit serious systemic effects. There has been much scientific debate about the most appropriate first aid for these stings, particularly with regard to whether vinegar use is appropriate (most current recommendations recommend against vinegar). We found that only a small percentage (≤1.0%) of tentacle cnidae discharge during a sting event using an ex vivo tissue model which elicits spontaneous stinging from live cnidarian tentacles. We then tested a variety of rinse solutions on both Atlantic and Pacific Physalia species to determine if they elicit cnidae discharge, further investigating any that did not cause immediate significant discharge to determine if they are able to inhibit cnidae discharge in response to chemical and physical stimuli. We found commercially available vinegars, as well as the recently developed Sting No More® Spray, were the most effective rinse solutions, as they irreversibly inhibited cnidae discharge. However, even slight dilution of vinegar reduced its protective effects. Alcohols and folk remedies, such as urine, baking soda and shaving cream, caused varying amounts of immediate cnidae discharge and failed to inhibit further discharge, and thus likely worsen stings.

Cubozoan Sting-Site Seawater Rinse, Scraping, and Ice Can Increase Venom Load: Upending Current First Aid Recommendations

Cnidarian envenomations are the leading cause of severe and lethal human sting injuries from marine life. The total amount of venom discharged into sting-site tissues, sometimes referred to as "venom load", has been previously shown to correlate with tentacle contact length and sequelae severity. Since <1% of cnidae discharge upon initial tentacle contact, effective and safe removal of adherent tentacles is of paramount importance in the management of life-threatening cubozoan stings. We evaluated whether common rinse solutions or scraping increased venom load as measured in a direct functional assay of venom activity (hemolysis). Scraping significantly increased hemolysis by increasing cnidae discharge. For Alatina alata, increases did not occur if the tentacles were first doused with vinegar or if heat was applied. However, in Chironex fleckeri, vinegar dousing and heat treatment were less effective, and the best outcomes occurred with the use of venom-inhibiting technologies (Sting No More® products). Seawater rinsing, considered a "no-harm" alternative, significantly increased venom load. The application of ice severely exacerbated A. alata stings, but had a less pronounced effect on C. fleckeri stings, while heat application markedly reduced hemolysis for both species. Our results do not support scraping or seawater rinsing to remove adherent tentacles.

The clinical manifestations, outcome and identification of jellyfish stings in Jaffna, Sri Lanka

We carried out a descriptive study over one year on 62 fishermen stung by jellyfish while fishing. Most were aged under 60 years. The timing of the sting was mostly between midnight and 4am (32%). Clinical symptoms were mainly localised pain and burning (80%), itching (67%) and shortness of breath (42%). Almost all patients received antihistamines (97%) and steroids (87%). None of them needed intensive care; they needed only 1-2 days in hospital. Jellyfish identified in fishing nets were Catostylus mosaicus, Cynea capillata and moon jellyfish.

Box Jellyfish Alatina alata Has a Circumtropical Distribution

Species of the box jellyfish (Cubozoa) genus Alatina are notorious for their sting along the beaches of several localities of the Atlantic and Pacific. These species include Alatina alata on the Caribbean Island of Bonaire (the Netherlands), A. moseri in Hawaii, and A. mordens in Australia. Most cubozoans inhabit coastal waters, but Alatina is unusual in that specimens have also been collected in the open ocean at great depths. Alatina is notable in that populations form monthly aggregations for spermcast mating in conjunction with the lunar cycle. Nominal species are difficult to differentiate morphologically, and it has been unclear whether they are distinct or a single species with worldwide distribution. Here we report the results of a population genetic study, using nuclear and mitochondrial sequence data from four geographical localities. Our analyses revealed a general lack of geographic structure among Alatina populations, and slight though significant isolation by distance. These data corroborate morphological and behavioral similarities observed in the geographically disparate localities, and indicate the presence of a single, pantropically distributed species, Alatina alata. While repeated, human-mediated introductions of A. alata could explain the patterns we have observed, it seems more likely that genetic metapopulation cohesion is maintained via dispersal through the swimming medusa stage, and perhaps via dispersal of encysted planulae, which are described here for the first time in Alatina.

To Pee, or Not to Pee: A Review on Envenomation and Treatment in European Jellyfish Species

There is a growing cause for concern on envenoming European species because of jellyfish blooms, climate change and globalization displacing species. Treatment of envenomation involves the prevention of further nematocyst release and relieving local and systemic symptoms. Many anecdotal treatments are available but species-specific first aid response is essential for effective treatment. However, species identification is difficult in most cases. There is evidence that oral analgesics, seawater, baking soda slurry and 42-45 °C hot water are effective against nematocyst inhibition and giving pain relief. The application of topical vinegar for 30 s is effective on stings of specific species. Treatments, which produce osmotic or pressure changes can exacerbate the initial sting and aggravate symptoms, common among many anecdotal treatments. Most available therapies are based on weak evidence and thus it is strongly recommended that randomized clinical trials are undertaken. We recommend a vital increase in directed research on the effect of environmental factors on envenoming mechanisms and to establish a species-specific treatment. Adequate signage on jellyfish stings and standardized first aid protocols with emphasis on protective equipment and avoidance of jellyfish to minimize cases should be implemented in areas at risk.

Heated Debates: Hot-Water Immersion or Ice Packs as First Aid for Cnidarian Envenomations?

Cnidarian envenomations are an important public health problem, responsible for more deaths than shark attacks annually. For this reason, optimization of first-aid care is essential. According to the published literature, cnidarian venoms and toxins are heat labile at temperatures safe for human application, which supports the use of hot-water immersion of the sting area(s). However, ice packs are often recommended and used by emergency personnel. After conducting a systematic review of the evidence for the use of heat or ice in the treatment of cnidarian envenomations, we conclude that the majority of studies to date support the use of hot-water immersion for pain relief and improved health outcomes.