Marine antivenoms

Toxin metalloproteinases exert a dominant influence on pro-inflammatory response and anti-inflammatory regulation in jellyfish sting dermatitis

Toxin metalloproteinases are the primary components responsible for various toxicities in jellyfish venom, and there is still no effective specific therapy for jellyfish stings. The comprehension of the pathogenic mechanisms underlying toxin metalloproteinases necessitates further refinement. In this study, we conducted a differential analysis of a dermatitis mouse model induced by jellyfish Nemopilema nomurai venom (NnNV) samples with varying levels of metalloproteinase activity. Through skin tissue proteomics and serum metabolomics, the predominant influence of toxin metalloproteinase activity on inflammatory response was revealed, and the signal pathway involved in its regulation was identified. In skin tissues, many membrane proteins were significantly down-regulated, which might cause tissue damage. The expression of pro-inflammatory factors was mainly regulated by PI3K-Akt signaling pathway. In serum, many fatty acid metabolites were significantly down-regulated, which might be the anti-inflammation feedback regulated by NF-κB p65 signaling pathway. These results reveal the dermatitis mechanism of toxin metalloproteinases and provide new therapeutic targets for further studies. SIGNIFICANCE: Omics is an important method to analyze the pathological mechanism and discover the key markers, which can reveal the pathological characteristics of jellyfish stings. Our research first analyzed the impact of toxin metalloproteinases on jellyfish sting dermatitis by skin proteomics and serum metabolomics. The present results suggest that inhibition of toxin metalloproteinases may be an effective treatment strategy, and provide new references for further jellyfish sting studies.

Rapid and permanent cytotoxic effects of venom from Chiropsella bronzie and Malo maxima on human skeletal and cardiac muscle cells

Jellyfish envenomation is a global public health risk; Cubozoans (box jellyfish) are a prevalent jellyfish class with some species causing potent and potentially fatal envenomation in tropical Australian waters. Previous studies have explored the mechanism of action of venom from the lethal Cubozoan Chironex fleckeri and from Carukia barnesi (which causes "Irukandji syndrome"), but mechanistic knowledge to develop effective treatment is still limited. This study performed an in-vitro cytotoxic examination of the venoms of Chiropsella bronzie and Malo maxima, two understudied species that are closely related to Chironex fleckeri and Carukia barnesi respectively. Venom was applied to human skeletal muscle cells and human cardiomyocytes while monitoring with the xCELLigence system. Chiropsella bronzie caused rapid cytotoxicity at concentrations as low as 58.8 μg/mL. Malo maxima venom caused a notable increase in cell index, a measure of cell viability, followed by cytotoxicity after 24-h venom exposure at ≥11.2 μg/mL on skeletal muscle cells. In contrast, the cardiomyocytes mostly showed significant increased cell index at the higher M. maxima concentrations tested. These findings show that these venoms can exert cytotoxic effects and Malo maxima venom mainly caused a sustained increase in cell index across both human cell lines, suggesting a different mode of action to Chiropsella bronzie. As these venoms show different real-world envenomation symptoms, the different cellular toxicity profiles provide a first step towards developing improved understanding of mechanistic pathways and novel envenomation treatment.

The Geographic Distribution, Venom Components, Pathology and Treatments of Stonefish (Synanceia spp.) Venom

Stonefish are regarded as one of the most venomous fish in the world. Research on stonefish venom has chiefly focused on the in vitro and in vivo neurological, cardiovascular, cytotoxic and nociceptive effects of the venom. The last literature review on stonefish venom was published over a decade ago, and much has changed in the field since. In this review, we have generated a global map of the current distribution of all stonefish (Synanceia) species, presented a table of clinical case reports and provided up-to-date information about the development of polyspecific stonefish antivenom. We have also presented an overview of recent advancements in the biomolecular composition of stonefish venom, including the analysis of transcriptomic and proteomic data from Synanceia horrida venom gland. Moreover, this review highlights the need for further research on the composition and properties of stonefish venom, which may reveal novel molecules for drug discovery, development or other novel physiological uses.

Identifying and revealing the geographical variation in Nemopilema nomurai venom metalloprotease and phospholipase A2 activities

Venom geographical variation is common among venomous animals. This phenomenon presents problems in the development of clinical treatments and medicines against envenomation. The venomous giant jellyfish Nemopilema nomurai, Scyphozoan, is a blooming jellyfish species in the Yellow Sea and the East China Sea that causes numerous jellyfish sting cases every year. Metalloprotease and phospholipase A₂ (PLA₂) are the main components in Nemopilema nomurai venom and may activate many toxicities, such as hemolysis, inflammation and lethality. Geographical variation in the content and activity of these enzymes may cause different symptoms and therapeutic problems. For the first time, we verified metalloprotease and PLA₂ geographical variation in Nemopilema nomurai venom by performing a comparative analysis of 31 venom samples by SDS-PAGE, analyzing protease zymography, enzymatic activity, and drawing contour maps. Band locations and intensities of SDS-PAGE and protease zymograms showed geographical differences. The enzymatic activities of both metalloprotease and PLA₂ showed a trend of geographic regularity. The distribution patterns of these activities are directly shown in contour maps. Metalloproteinase activity was lower near the coast. PLA₂-like activity was lower in the Southern Yellow Sea. We surmised that metalloproteinase and PLA₂-like activities might be related to venom ontogeny and species abundance respectively, and influenced by similar environmental factors. This study provides a theoretical basis for further ecological and medical studies of Nemopilema nomurai jellyfish venom.

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.

The pathology of Chironex fleckeri venom and known biological mechanisms

The large box jellyfish Chironex fleckeri is found in northern Australian waters. A sting from this cubozoan species can kill within minutes. From clinical and animal studies, symptoms comprise severe pain, welts, scarring, hypotension, vasospasms, cardiac irregularities and cardiac arrest. At present, there is no cure and opioids are used to manage pain. Antivenom is available but controversy exists over its effectiveness. Experimental and combination therapies performed in vitro and in vivo have shown varied efficacy. These inconsistent results are likely a consequence of the different methods used to extract venom. Recent omics analysis has shed light on the systems of C. fleckeri venom action, including new toxin classes that use pore formation, cell membrane collapse and ion channel modulation. This review covers what is known on C. fleckeri pathomechanisms and highlights current gaps in knowledge. A more complete understanding of the mechanisms of C. fleckeri venom-induced pathology may lead to novel treatments and possibly, the discovery of novel cell pathways, novel drug scaffolds and novel drug targets for human disease.

Isolation, Structure Determination, and Synthesis of Cyclic Tetraglutamic Acids from Box Jellyfish Species Alatina alata and Chironex yamaguchii

Cubozoan nematocyst venoms contain known cytolytic and hemolytic proteins, but small molecule components have not been previously reported from cubozoan venom. We screened nematocyst extracts of Alatina alata and Chironex yamaguchii by LC-MS for the presence of small molecule metabolites. Three isomeric compounds, cnidarins 4A (1), 4B (2), and 4C (3), were isolated from venom extracts and characterized by NMR and MS, which revealed their planar structure as cyclic γ-linked tetraglutamic acids. The full configurational assignments were established by syntheses of all six possible stereoisomers, comparison of spectral data and optical rotations, and stereochemical analysis of derivatized degradation products. Compounds 1-3 were subsequently detected by LC-MS in tissues of eight other cnidarian species. The most abundant of these compounds, cnidarin 4A (1), showed no mammalian cell toxicity or hemolytic activity, which may suggest a role for these cyclic tetraglutamates in nematocyst discharge.

Dermatological Progression of a Probable Box Jellyfish Sting

This case report describes the typical features of the dermatological progression of a patient stung by a (probable) box jellyfish. The purpose is to guide clinicians and patients to an understanding of what to expect after such a sting using the clinical narrative and unique sequential photographs of the injury. With knowledgeable consultation from experienced physicians and meticulous care, this envenomation healed without the need for skin grafting.

Molecular dissection of box jellyfish venom cytotoxicity highlights an effective venom antidote

The box jellyfish Chironex fleckeri is extremely venomous, and envenoming causes tissue necrosis, extreme pain and death within minutes after severe exposure. Despite rapid and potent venom action, basic mechanistic insight is lacking. Here we perform molecular dissection of a jellyfish venom-induced cell death pathway by screening for host components required for venom exposure-induced cell death using genome-scale lenti-CRISPR mutagenesis. We identify the peripheral membrane protein ATP2B1, a calcium transporting ATPase, as one host factor required for venom cytotoxicity. Targeting ATP2B1 prevents venom action and confers long lasting protection. Informatics analysis of host genes required for venom cytotoxicity reveal pathways not previously implicated in cell death. We also discover a venom antidote that functions up to 15 minutes after exposure and suppresses tissue necrosis and pain in mice. These results highlight the power of whole genome CRISPR screening to investigate venom mechanisms of action and to rapidly identify new medicines.

Box jellyfish venom causes tissue damage, pain, and death through unknown molecular mechanisms. Here, Lau et al. perform a CRISPR screen to identify genes required for venom action and use this information to develop an antidote that blocks venom-induced pain and tissue damage in vivo.

Venomous Fish Sting Cases Reported to Hong Kong Poison Information Centre: A Three-Year Retrospective Study on Epidemiology and Management

Objective

To study the epidemiology of venomous fish sting injuries, management and clinical outcomes of injured patients reported to the Hong Kong Poison Information Centre (HKPIC).

Methods

All venomous fish sting cases reported to HKPIC from July 2005 to June 2008 were retrieved from its database (DATOX) and the Hong Kong Hospital Authority (HA) Electronic Patient Record (ePR) computer system for analysis.

Results

There were a total of 33 fish sting cases in this study. The average age of the patients was 43 years (range 20 to 84) and 24 patients were males. Most cases were injured by catfish (n=12), followed by stonefish (n=7) and lionfish (n=4). Ten cases sustained fish sting injury whilst at work. Five patients developed fish sting complications including cellulitis, subacute tenosynovitis, abscess formation and foreign body retention. No mortality was recorded. Within 7 cases of stonefish injury, 3 cases were classified as moderate effect outcome. Two patients received stonefish antivenom and none developed anaphylaxis.

Conclusion

The majority of marine envenomations did not result in significant morbidity and required only supportive management. However, stonefish injuries might be associated with an increased risk of severe local symptoms which therefore required aggressive treatment including antivenom.

Watch Out for Wild Animals: A Systematic Review of Upper Extremity Injuries Caused by Uncommon Species

BACKGROUND

Across the world, many species of nondomesticated animals dwell among humans in metropolitan areas. Rare animal bites pose a dilemma for hand surgeons, as they often result in operative injuries and recalcitrant infections. The authors treated an 85-year-old man who experienced severe cellulitis of the index finger following an opossum bite. This case prompted a systematic review of upper extremity injuries caused by species other than dogs, cats, snakes, and insects.

METHODS

The authors conducted a systematic review of PubMed and Scopus databases to identify relevant articles published between 1980 and 2016. Two reviewers critically appraised the studies that met inclusion and exclusion criteria.

RESULTS

The hand infection in the man who sustained an opossum bite at the authors' institution was successfully treated with targeted antibiotic therapy, hand elevation, and splinting. Seventy-one articles met inclusion criteria for and were included in this systematic review. The vast majority of existing articles represent level IV and level V evidence. The relevant literature suggests that the majority of hand infections attributable to animal bites and stings are polymicrobial.

CONCLUSIONS

Injuries secondary to aquatic animals appear to be the most frequently described in the literature, and hot water immersion should be used for the majority of envenomation attributable to aquatic species. Infections can often be treated with an aminopenicillin antibiotic combined with a beta-lactamase inhibitor. Given the variability in presentation and potential for sequelae such as soft-tissue necrosis and systemic reactions, hand surgeons should approach such upper extremity injuries with a high degree of caution.

Melatonin inhibits snake venom and antivenom induced oxidative stress and augments treatment efficacy

Snakebite is a neglected health hazard. Its patho-physiology has largely been focused on systemic and local toxicities; whereas, venom and antivenom induced oxidative stress has long been ignored. Antivenom therapy although neutralizes venom lethality and saves many lives, remains ineffective against oxidative stress. This prompted us to complement antivenom with an antioxidant molecule melatonin that would protect against oxidative stress and increase the efficacy of the existing snakebite therapy. Here we show that D. russelli and E. carinatus venoms induce strong oxidative stress that persists even after antivenom administration in mice model. Additionally, antivenoms also induce oxidative stress. Polyvalent antivenom induce more oxidative stress than monovalent antivenom. Strikingly, antivenom and melatonin together not only inhibit venom and antivenom induced oxidative stress but also significantly reduce the neutralizing antivenom dose. This study provides a therapeutic potential for enhancing the existing snakebite therapy. The combined treatment of antivenom+melatonin would prevent the upsurge of oxidative stress as well as minimize the antivenom load. Thus the investigation offers immense scope for physicians and toxinologists to reinvestigate, design new strategies and think beyond the conventional mode of antivenom therapy.

Got the Travel Bug? A Review of Common Infections, Infestations, Bites, and Stings Among Returning Travelers

The popularity of international travel continues to increase among Americans, even though they often experience subsequent illness on return from their journey. The pathogens responsible are not necessarily endemic to the destination itself but are often the result of poor sanitary conditions or activities engaged in while away. Skin disease ranks third among all medical concerns in returning travelers. This review addresses the pathogenesis, epidemiology, clinical presentation, and treatment of the most common skin diseases in returning travelers: insect bites and bedbugs, cutaneous larva migrans, scabies, tungiasis, myiasis, leishmaniasis, viral exanthems, and marine envenomation. Primary care physicians and dermatologists should be familiar with these illnesses and a general approach to their evaluation and management.

[Jellyfish sting injuries]

BACKGROUND

Jellyfish are distributed worldwide; they cause local skin injuries upon contact which are often followed by systemic signs of envenoming.

OBJECTIVES

Which jellyfish species are of medical importance, which skin reactions and systemic symptoms occur, which first-aid measures and treatment options exist?

METHODS

Review of the medical literature and discussion of first-aid and therapeutic options.

RESULTS

Jellyfish capable of causing skin injuries occur in almost all oceans. Several jellyfish species may cause severe, potentially lethal, systemic symptoms; they include the Portuguese man-of-war (Physalia physalis) and box jellyfish (Chironex fleckeri, Carukia barnesi, Chiropsalmus quadrigatus).

CONCLUSIONS

Among the injuries and envenoming symptoms caused by marine organisms, jellyfish dermatitis should not be underestimated. Skin reactions may not only a dermatological problem, but also be accompanied by complex systemic toxic symptoms which are a challenge for internists.

Engineering venom's toxin-neutralizing antibody fragments and its therapeutic potential

Serum therapy remains the only specific treatment against envenoming, but anti-venoms are still prepared by fragmentation of polyclonal antibodies isolated from hyper-immunized horse serum. Most of these anti-venoms are considered to be efficient, but their production is tedious, and their use may be associated with adverse effects. Recombinant antibodies and smaller functional units are now emerging as credible alternatives and constitute a source of still unexploited biomolecules capable of neutralizing venoms. This review will be a walk through the technologies that have recently been applied leading to novel antibody formats with better properties in terms of homogeneity, specific activity and possible safety.

Dose and time dependence of box jellyfish antivenom

Background

The effectiveness of the currently available box jellyfish (Chironex fleckeri) antivenom has been subject of debate for many years. To assess whether the box jellyfish antivenom has the ability to attenuate venom-induced damage at cellular level, the present study analyzed the dose and time dependence of the antivenom in a cell-based assay.

Methods

Different doses of antivenom were added to venom and subsequently administered to cells and the cell index was measured using xCelligence Technology (ACEA Biosciences). Similarly, antivenom and venom were incubated over different time periods and cell survival measured as stated above. For both experiments, the cell index was plotted as a measure of cell survival against the dose or incubation time and significance was determined with the use of a one-way ANOVA with a LSD post hoc test.

Results

Increasing concentrations of antivenom significantly augmented cell survival, with a concentration of approximately five times the currently recommended dose for human envenomation, causing the first significant increase in cell survival compared venom alone. Further, cell survival improved with increasing incubation time of venom and antivenom prior to addition to the cells, indicating that box jellyfish antivenom requires approximately 70 minutes to neutralize C. fleckeri venom.

Conclusion

The presented results suggest that the currently recommended dose of antivenom requires adjustment, and more importantly, a human trial to test the effects of higher concentrations is also necessary. Further, antivenom has delayed neutralizing effects (i.e. after 70 minutes) which underlines the eminence of immediate and prolonged cardiopulmonary resuscitation in victims suffering from a C. fleckeri venom-induced cardiovascular collapse.

Jellyfish stings and their management: a review

Jellyfish (cnidarians) have a worldwide distribution. Despite most being harmless, some species may cause local and also systemic reactions. Treatment of jellyfish envenomation is directed at: alleviating the local effects of venom, preventing further nematocyst discharges and controlling systemic reactions, including shock. In severe cases, the most important step is stabilizing and maintaining vital functions. With some differences between species, there seems to be evidence and consensus on oral/topical analgesics, hot water and ice packs as effective painkillers and on 30 s application of domestic vinegar (4%-6% acetic acid) to prevent further discharge of unfired nematocysts remaining on the skin. Conversely, alcohol, methylated spirits and fresh water should be carefully avoided, since they could massively discharge nematocysts; pressure immobilization bandaging should also be avoided, as laboratory studies show that it stimulates additional venom discharge from nematocysts. Most treatment approaches are presently founded on relatively weak evidence; therefore, further research (especially randomized clinical trials) is strongly recommended. Dissemination of appropriate treatment modalities should be deployed to better inform and educate those at risk. Adequate signage should be placed at beaches to notify tourists of the jellyfish risk. Swimmers in risky areas should wear protective equipment.

A pharmacological investigation of the venom extract of the Australian box jellyfish, Chironex fleckeri, in cardiac and vascular tissues

The pharmacology of Australian box jellyfish, Chironex fleckeri, unpurified (crude) nematocyst venom extract (CVE) was investigated in rat isolated cardiac and vascular tissues and in anaesthetised rats. In small mesenteric arteries CVE (0.01-30 μg/ml) caused contractions (EC(50) 1.15±0.19 μg/ml) that were unaffected by prazosin (0.1 μM), bosentan (10 μM), CGRP(8-37) (1 μM) or tetrodotoxin (1 μM). Box jellyfish antivenom (5-92.6 units/ml) caused rightward shifts of the CVE concentration-response curve with no change in the maximum. In the presence of l-NAME (100 μM) the sensitivity and maximum response to CVE were increased, whilst MgSO(4) (6 mM) decreased both parameters. CVE (1-10 μg/ml) caused inhibition of the contractile response to electrical sympathetic nerve stimulation. Left atrial responses to CVE (0.001-30 μg/ml) were bi-phasic, composed of an initial positive inotropy followed by a marked negative inotropy and atrial standstill. CVE (0.3 μg/ml) elicited a marked decrease in right atrial rate followed by atrial standstill at 3 μg/ml. These responses were unaffected by 1 μM of propranolol, atropine or CGRP(8-37). Antivenom (54 and 73 units/ml) caused rightward shifts of the CVE concentration-response curve and prevented atrial standstill in left and right atria. The effects of CVE do not appear to involve autonomic nerves, post-synaptic α(1)- or β(1)-adrenoceptors, or muscarinic, endothelin or CGRP receptors, but may occur through direct effects on the cardiac and vascular muscle. Box jellyfish antivenom was effective in attenuating CVE-induced responses in isolated cardiac and vascular tissues.

Evolution of box jellyfish (Cnidaria: Cubozoa), a group of highly toxic invertebrates

Cubozoa (Cnidaria: Medusozoa) represents a small clade of approximately 50 described species, some of which cause serious human envenomations. Our understanding of the evolutionary history of Cubozoa has been limited by the lack of a sound phylogenetic hypothesis for the group. Here, we present a comprehensive cubozoan phylogeny based on ribosomal genes coding for near-complete nuclear 18S (small subunit) and 28S (large subunit) and partial mitochondrial 16S. We discuss the implications of this phylogeny for our understanding of cubozoan venom evolution, biogeography and life-history evolution. Our phylogenetic hypothesis suggests that: (i) the last common ancestor of Carybdeida probably possessed the mechanism(s) underlying Irukandji syndrome, (ii) deep divergences between Atlantic and Indo-Pacific clades may be explained by ancient vicariant events, and (iii) sexual dimorphism evolved a single time in concert with complex sexual behaviour. Furthermore, several cubozoan taxa are either para- or polyphyletic, and we address some of these taxonomic issues by designating a new family, Carukiidae, a new genus, Copula, and by redefining the families Tamoyidae and Tripedaliidae. Lastly, cubozoan species identities have long been misunderstood and the data presented here support many of the recent scientific descriptions of cubozoan species. However, the results of a phylogeographic analysis of Alatina moseri from Hawai'i and Alatina mordens from Australia indicate that these two nominal species represent a single species that has maintained metapopulation cohesion by natural or anthropogenic dispersal.

Antivenom efficacy or effectiveness: the Australian experience

Despite widespread use of antivenoms, many questions remain about their effectiveness in the clinical setting. The almost universal acceptance of their value is based mainly on in vitro studies, animal studies and human observational studies. Numerous examples exist where they demonstrate clear benefit, such as consumption coagulopathy in viper envenoming, prevention of neurotoxicity in Australasian elapid bites, systemic effects in scorpion and funnel-web spider envenoming. There are also concerns about the quality and efficacy of some antivenoms. However, it is important not to confuse the efficacy of antivenom, defined as its ability to bind and neutralise venom-mediated effects under ideal conditions, and the effectiveness of antivenom, defined as its ability to reverse or prevent envenoming in human cases. There are numerous potential reasons for antivenom failure in human envenoming, of which antivenom inefficacy is only one. Other important reasons include venom-mediated effects being irreversible, antivenom being unable to reach the site of toxin-mediated injury, or the rapidity of onset of venom-mediated effects. A number of recent studies in Australia bring into question the effectiveness of some antivenoms, including snake antivenom for coagulopathy, redback spider and box jellyfish antivenoms. Despite brown snake antivenom being able to neutralise venom induced clotting in vitro, use of the antivenom in human envenoming does not appear to change the time course of coagulopathy. However, it is important that apparent antivenom ineffectiveness in specific cases is correctly interpreted and does not lead to a universal belief that antivenom is ineffective. It should rather encourage further studies to investigate the underlying pathophysiology of envenoming, the pharmacokinetics of venoms and antivenoms, and ultimately the effectiveness of antivenom based on snake type, clinical effects and timing of administration.

An in vivo comparison of the efficacy of CSL box jellyfish antivenom with antibodies raised against nematocyst-derived Chironex fleckeri venom

Although CSL box jellyfish antivenom (AV) remains the primary treatment for Chironex fleckeri envenoming, there has been considerable debate regarding its clinical effectiveness. Animal studies have shown that AV is largely ineffective in preventing C. fleckeri-induced cardiovascular collapse. This study examined the effectiveness of CSL box jellyfish AV (ovine IgG), raised against 'milked' venom, and polyclonal rabbit IgG antibodies (Ab) raised against nematocyst-derived venom. A venom dose of 30microg/kg, i.v., which causes an initial presser response (34+/-5mmHg; n=7) followed by cardiovascular collapse, was used in all experiments. A bolus dose of AV (3000U/kg, i.v.) or Ab (12mg; i.e. an equivalent protein 'load' to 3000U/kg AV), administered 15min prior to a bolus dose of venom, did not significantly attenuate the effects of venom. The venom response was also not significantly attenuated when AV (3000U/kg) was given as a bolus dose 10-60min prior to venom infusion. However, when the venom was incubated with either AV (3000U/kg) or Ab (12mg) for 3h prior to infusion, the effect of the venom was almost abolished. The results of this study demonstrate that antibodies raised against both 'milked' and nematocyst-derived venom are able to neutralise the cardiovascular collapse produced by the venom. However, large amounts of AV are required and must be preincubated with the venom to be protective. This indicates a very rapid action of the toxin(s) and that AV is unlikely to be clinically effective because it cannot be administered early enough.

[Jellyfish sting. A case report]

Jellyfish bites in Hungary are rare. Yet, from a differential diagnostic point of view this epizoonozis might gain importance given the ever-growing popularity of seaside tourism. A 10 year old female patient was stung by a jellyfish while sea-bathing in the Adriatic in the summer of 2005. A couple of minutes after the bite urticaria were formed in the contacted area accompanied by a burning and sore sensation. In a few hours the above lesions turned livid and the patient developed low-grade fever and general discomfort. In acute therapy she received thorough rinse with vinegar, antibiotic ointment and systemic calcium. General symptoms regressed within 24 hours and dermatological symptoms improved progressively. Finally, the patient grew symptomless in 4 weeks altogether due to general antihistamine and local antibiotic therapy. 3 months later the patient presented again with hyperaemic papules and an increasing itching and burning sensation in the previously jellyfish-contacted area. Histopathology showed vascular involvement and eosinophilic infiltration. The inflammatory symptoms gradually diminished to locally applied steroids in an occlusive bandage leaving behind hypopigmentation. Although bare-skin contact with the different poisonous jellyfish species usually do lead to the forming of dermatological symptoms, vascular involvement developed months after the encounter in the exposure site has seldom been published. The article covers the main potential symptoms of jellyfish stings--both local and general--going into details about the possible dermatological differential diagnoses. Furthermore, the most venomous jellyfish species, their geographical habitats, do's and don't-s of first aid, therapy and prevention are being briefly discussed by the authors.

Neutralizing antibodies obtained in a persistent immune response are effective against deleterious effects induced by the Thalassophryne nattereri fish venom

Thalassophryne nattereri envenoming represents a great cost to North and Northeast Brazilian communities in terms of public healths, leisure and tourism. Victims rapidally develop symptoms as pain, local swelling, erythema followed by intense necrosis that persist for long days. The aim of this work was tested the immune competence of neutralizing antibodies in pre-immunized mice against principal toxic activities induced by venom. During the primary antibody response in mice, an elevation of IgG antibody levels was only observed on day 28. After boosting, high antibody levels were detected between days 49 and 70, with a 12-fold increase in IgG level over control values at day 49. We confirmed the in vitro neutralizing capacity of T. nattereri anti-venom against toxic effects and thereafter we show that neutralizing antibodies obtained in a persistent immune response are more effective, inclusive against edematous reaction. After boosting during the secondary response mice with high antibody levels do not present any alterations in venule or arteriole after topical application of venom on cremaster muscle. In addition, CK activity diminished in these mice with high neutralizing antibody levels corroborating the attenuation of the myonecrotic effect by venom. In addition, we determined the presence of high IgG antibodies levels in patients 6 months after injury by T. nattereri. In conclusion, the presence of neutralizing antibodies against to T. nattereri venom in the serum of pre-immunized mice could change the outcome of lesion at site of posterior envenoming. Antigen-specific antibodies of high affinity in consequence to specific immune response, dependent of T lymphocyte activation, could minimize the symptoms of intense and immediate inflammatory reaction caused by T. nattereri venom. These finding prompt us to the possibility of development of immune therapeutic strategies using specific anti-venom as an efficient intervention for protecting human victims.

An in vivo examination of the stability of venom from the Australian box jellyfish Chironex fleckeri

We have previously characterised the pharmacological activity of a number of jellyfish venoms with a particular emphasis on the profound cardiovascular effects. It has been suggested that jellyfish venoms are difficult to work with and are sensitive to pH, temperature and chemical changes. The current study aimed to examine the working parameters of the venom of the Australian box jellyfish Chironex fleckeri to enable fractionation and isolation of the toxins with cardiovascular activity. C. fleckeri venom was made up fresh each day and subjected to a number of different environments (i.e. a pH range of 5-9 and a temperature range of 4-30 degrees C). In addition, the effect of freeze drying and reconstituting the venom was investigated. Venom (50 microg/kg, i.v.) produced a transient hypertensive response followed by cardiovascular collapse in anaesthetised rats. This biphasic response was not significantly effected by preparation of the venom at a pH of 5, 7 or 9. Similarly, venom (50 microg/kg, i.v.) did not display a loss of activity when exposed to temperatures of 4, 20 or 30 degrees C for 1.5h. However, the cardiovascular activity was abolished by boiling the venom. Freeze drying, and then reconstituting, the venom did not significantly affect its cardiovascular activity. However, repeated freeze drying and reconstituting of extracted venom resulted in a significantly loss of activity. This study provides a more detailed knowledge of the parameters in which C. fleckeri venom can be used and, while supporting some previous studies, contradicts some of the perceived problems of working with the venom.

Prospective study of Chironex fleckeri and other box jellyfish stings in the “Top End” of Australia's Northern Territory

OBJECTIVE

To describe the epidemiology and clinical features of box jellyfish envenoming in the Top End of the Northern Territory and, in particular, confirmed stings from the major Australian box jellyfish, Chironex fleckeri.

DESIGN

Prospective collection of clinical data and skin scrapings or sticky-tape tests for nematocyst identification from patients presenting to Royal Darwin Hospital and remote coastal community health clinics in the Northern Territory, spanning 10 950 km of coastline; analysis of tidal, weather and seasonal data.

PATIENTS

All patients with jellyfish sting details recorded between 1 April 1991 and 30 May 2004.

MAIN OUTCOME MEASURES

Demographic and clinical features, use of C. fleckeri antivenom, and associations between weather, seasonal and tidal factors and confirmed C. fleckeri stings.

RESULTS

Of 606 jellyfish stings documented, 225 were confirmed to have been caused by C. fleckeri. 37% of C. fleckeri stings were in children, 92% occurred during the "stinger season" (1 October to 1 June), 83% occurred in water 1 m or less deep, and 17% occurred while victims were entering the water. Stings were least common on outgoing tides (P < 0.001) and commonest between 15:00 and 18:00 (P < 0.001) and on days with wind speed less than that month's average (P < 0.001). Nearly all victims experienced immediate pain, but this could often be controlled with ice; only 30% required parenteral narcotics and 8% required hospital admission. Cardiorespiratory arrest occurred within several minutes of the sting in the one fatal case, involving a 3-year-old girl with only 1.2 m of visible tentacle contact. C. fleckeri antivenom was given to another 21 patients, none of whom had life-threatening features at the time they were given antivenom.

CONCLUSIONS

Most C. fleckeri stings are not life-threatening; patients who die usually have cardiopulmonary arrest within minutes of the sting. The potential benefit of antivenom and magnesium under these circumstances remains to be shown, but a protocol with their rapid use is recommended if cardiopulmonary arrest has occurred. Unfortunately, this is unrealistic for many rural coastal locations, and the priority remains prevention of stings by keeping people, especially children, out of the sea during the stinger season.

Illnesses caused by marine toxins

Marine toxins are produced by algae or bacteria and are concentrated in contaminated seafood. Substantial increases in seafood consumption in recent years, together with globalization of the seafood trade, have increased potential exposure to these agents. Marine toxins produce neurological, gastrointestinal, and cardiovascular syndromes, some of which result in high mortality and long-term morbidity. Routine clinical diagnostic tests are not available for these toxins; diagnosis is based on clinical presentation and a history of eating seafood in the preceding 24 h. There is no antidote for any of the marine toxins, and supportive care is the mainstay of treatment. In particular, paralytic shellfish poisoning and puffer fish poisoning can cause death within hours after consuming the toxins and may require immediate intensive care. Rapid notification of public health authorities is essential, because timely investigation may identify the source of contaminated seafood and prevent additional illnesses. Extensive environmental monitoring and sometimes seasonal quarantine of a harvest are employed to reduce the risk of exposure.

Assessment of the viral safety of antivenoms fractionated from equine plasma

Antivenoms are preparations of intact or fragmented (F(ab′)₂ or Fab) immunoglobulin G (IgG) used in human medicine to treat the severe envenomings resulting from the bites and stings of various animals, such as snakes, spiders, scorpions, or marine animals, or from the contact with poisonous plants. They are obtained by fractionating plasma collected from immunized horses or, less frequently, sheep. Manufacturing processes usually include pepsin digestion at acid pH, papain digestion, ammonium sulphate precipitation, caprylic acid precipitation, heat coagulation and/or chromatography. Most production processes do not have deliberately introduced viral inactivation or removal treatments, but antivenoms have never been found to transmit viruses to humans. Nevertheless, the recent examples of zoonotic diseases highlight the need to perform a careful assessment of the viral safety of antivenoms.

This paper reviews the characteristics of equine viruses of antivenoms and discusses the potential of some manufacturing steps to avoid risks of viral contamination. Analysis of production parameters indicate that acid pH treatments and caprylic acid precipitations, which have been validated for the manufacture of some human IgG products, appear to provide the best potential for viral inactivation of antivenoms. As many manufacturers of antivenoms located in developing countries lack the resources to conduct formal viral validation studies, it is hoped that this review will help in the scientific understanding of the viral safety factors of antivenoms, in the controlled implementation of the manufacturing steps with expected impact on viral safety, and in the overall reinforcement of good manufacturing practices of these essential therapeutic products.

The in vivo cardiovascular effects of box jellyfish Chironex fleckeri venom in rats: efficacy of pre-treatment with antivenom, verapamil and magnesium sulphate

Using a new technique to extract venom from the nematocysts, the efficacy of CSL box jellyfish antivenom (AV) and adjunct therapies, verapamil and magnesium sulfate (MgSO(4)), were investigated against the in vivo cardiovascular effects of Chironex fleckeri venom in anaesthetised rats. C. fleckeri venom (30 microg/kg; i.v.) produced a transient hypertensive response followed by hypotension and cardiovascular collapse within 4 min of administration. Prophylactic treatment of anaesthetised rats with CSL box jellyfish AV (3000 U/kg; i.v.) did not have any effect on the venom-induced pressor response, but prevented cardiovascular collapse in four out of 10 animals. Administration of verapamil (20mM@0.25 ml/min; i.v.) either alone or in combination with AV, did not have any effect on the C. fleckeri venom-induced pressor response nor the consequent hypotension or cardiovascular collapse of animals. However, the administration of verapamil negated the partially protective effects of AV. Concurrent artificial respiration of animals with the above treatments did not attenuate the C. fleckeri venom-induced cardiovascular effects. MgSO(4) (0.05-0.07M@0.25 ml/min; i.v.) alone did not have any effect on the venom-induced pressor response nor the consequent cardiovascular collapse of animals. However, although combined AV and MgSO(4) administration could not inhibit the transient pressor effect following the administration of C. fleckeri venom, it prevented cardiovascular collapse in all animals. We show for the first time, the cardiovascular effects of a C. fleckeri venom sample free of tentacular contamination and the potential of MgSO(4) as an adjunct therapy for the treatment of potentially fatal C. fleckeri envenomings.