Bites and stings of medically important venomous arthropods

IL, Duran CFD, Cammayo MFKM, Alviola MS, Mercado SMQ, Osio CAL, Eusebio OL, Lucañas CC, Barrion AT. Integrative taxonomy reveals first record of Loxoscelesrufescens (Dufour, 1820) (Araneae, Sicariidae) in the Philippines

Background

The spider family Sicariidae Keyserling, 1880 represented by the synanthropic Mediterranean recluse spider, Loxoscelesrufescens (Dufour, 1820), is reported in the Philippines for the first time, based on morphological and molecular data. The introduced spider was observed in a small cave (Kamantigue Cave) in Lobo, Batangas Province. Considering the medical importance of this spider, the proximity of its habitat to human habitation and tourist sites poses a potential public health concern.

New information

This study reports on the first record of the family Sicariidae in the Philippines and the fourth recorded occurrence of L.rufescens in Southeast Asia.

Experimental envenomation with honeybee venom melittin and phospholipase A2 induced multiple ultrastructural changes in adrenocortical mitochondria

Bee stings represent a public health subject, but the mechanisms involved in bee venom toxicity are not yet fully understood. To evaluate the reactions of adrenocortical cells, through which organisms respond to stress, two honeybee venom components: melittin (Mlt) and phospholipase A2 (PLA2) were tested as potential chemical stressors. Modifications were investigated with transmission electron microscopy and microanalysis. A single dose of Mlt (31 mg/kg) or PLA2 (9.3 mg/kg) was injected in rats of groups ML and PL; daily doses of Mlt (350 μg/kg) or PLA2 (105 μg/kg) were injected 30 days in rats of groups M30 and P30. Adrenocortical cells in ML group showed ultrastructural degenerative alterations of nuclei, endoplasmic reticulum, and mitochondria that exhibited lipid inclusions and mitochondrial cristae (MC) re-organized into mono- or multimembrane large vesicles, and whorls of membranes. Many MC were degenerated. In the M30 group, similar ultrastructural changes, but of lower amplitude were noted; lipid cytosolic droplets were heterogenous. MC diameters in Mlt groups (melittin treated groups) were significantly higher than in control (C) group. In PL group, mitochondria contained large lipid inclusions, vesicular MC of different sizes and multiple membranes, and debris, or whorl structures. In P30 group MC were tubular with increased diameters. In both PLA2 groups (PLA2 treated groups) MC were significantly larger than in C group. We concluded that Mlt and PLA2 were powerful stressors, toxic at the tested doses, cellular reactions concerning in all groups mainly mitochondria, but also other cellular compartments. Apart from degenerative regression of MC, the rearrangement of tubular MC occurred into one or multiple large multimembrane vesicular MC. Reactions to the high doses were more pronounced, with the highest amplitude in ML group, and the lowest in P30 group.

Subarachnoid hemorrhage following wasp stings: A case report

Three days after being stung by wasps in a rural area, a 60-year-old man was admitted to the emergency department with headaches. The physical examination showed that the patient was conscious, had moderate pain, had four head and back stings with local edema and erythema around the wounds, and had a stiff neck. Brain computed tomography upon admission revealed no abnormalities. Following lumbar puncture, the patient was diagnosed with subarachnoid hemorrhage (SAH) induced by wasp stings. No obvious aneurysms were found by either computed tomography angiography or three-dimensional rotational angiography. He received symptomatic treatment including antiallergy medication (chlorpheniramine and intravenous hydrocortisone), nimodipine for possible vasospasm, fluid infusion, and mannitol for intracranial pressure reduction and was discharged on the 14th day. This case of wasp sting-induced SAH is being reported to improve doctors' diagnostic abilities when encountering patients with wasp stings. It is important for emergency physicians to be aware that patients stung by wasps may develop rare complications such as SAH. Hymenoptera-induced SAH is an example of such a case.

Therapeutic Potential of Bee and Scorpion Venom Phospholipase A2 (PLA2): A Narrative Review

Venomous arthropods such as scorpions and bees form one of the important groups with an essential role in medical entomology. Their venom possesses a mixture of diverse compounds, such as peptides, some of which have toxic effects, and enzymatic peptide Phospholipase A2 (PLA2) with a pharmacological potential in the treatment of a wide range of diseases. Bee and scorpion venom PLA2 group III has been used in immunotherapy, the treatment of neurodegenerative and inflammatory diseases. They were assessed for antinociceptive, wound healing, anti-cancer, anti-viral, anti-bacterial, anti-parasitic, and anti-angiogenesis effects. PLA2 has been identified in different species of scorpions and bees. The anti-leishmania, anti-bacterial, anti-viral, and anti-malarial activities of scorpion PLA2 still need further investigation. Many pieces of research have been stopped in the laboratory stage, and several studies need vast investigation in the clinical phase to show the pharmacological potential of PLA2. In this review, the medical significance of PLA2 from the venom of two arthropods, namely bees and scorpions, is discussed.

Critical Upper Airway Edema After a Bee Sting to the Uvula

Hymenoptera stings of the upper airway are rare events, but can result in rapid, life-threatening airway emergencies. The allergenic and toxic mediators that are released from the stings of bees, wasps, and hornets can cause local tissue inflammation and edema with subsequent upper airway obstruction. We report the case of a 15-y-old girl who suffered a bee sting to the uvula while zip-lining in Costa Rica. Shortly thereafter, she developed a choking sensation with associated dysphonia, odynophagia, drooling, and respiratory distress. She was brought to a rural emergency medical clinic where she was noted to have an erythematous, edematous, boggy uvula, with a black stinger lodged within it, as well as edema of the anterior pillars of the tonsils and soft palate. The stinger was removed with tweezers and she was treated with an intravenous corticosteroid and antihistamine. She had persistence of airway edema and symptoms until the administration of epinephrine, which resulted in clinical improvement shortly thereafter. In our review of this case and the existing literature, we emphasize the importance of early recognition and management of hymenoptera stings of the upper airway, which should always include immediate manual removal of the stinger, and in cases with significant upper airway edema, the administration of epinephrine should be considered.

Knowledge, attitudes and control practices regarding venomous arthropods among staff and students in a Nigerian public university campus

BACKGROUND

The objectives of this study were to assess the knowledge, attitudes and control practices among the staff and students of Nnamdi Azikiwe University (NAU), Awka, Anambra State, Nigeria, regarding venomous arthropods.

METHODS

The knowledge, attitudes and control practices regarding venomous arthropods were assessed in 350 participants.

RESULTS

The respondents were aware of the presence of venomous arthropods at NAU and they had seen them on campus, with spiders (40.44%) being the most common and electric ants (1.39%) being the least common. The control practices applied to limit the activities of these arthropods included keeping the environment clean (40.80%), the use of insecticides (37.33%), the use of repellents (8.68%), spraying houses with kerosene (7.81%), spraying of fuel on the arthropods (3.47%), screening of houses (1.39%) and the use of bed nets (0.52%).

CONCLUSIONS

An assessment and determination of knowledge, attitudes and control practices regarding venomous arthropods among the staff and students of NAU is necessary in order to improve the preventive measures to reduce injuries caused by venomous arthropod encounters, which are some of the most underestimated health hazards in tropical regions, including southeastern Nigeria, affecting primarily rural communities. According to the findings of our study, students and staff at NAU are rarely involved in life-threatening incidents as a result of their encounters with venomous arthropods and most apply several globally accepted standard practices for the control of venomous arthropods.

Dengue Shock Syndrome: Its Similarity with Anaphylaxis and with the Homeopathic Medicine Apis mellifica (European Honeybee)

Dengue, with four viral serotypes, causes epidemics in tropical and sub-tropical regions. Allopathic antiviral therapies and a vaccine of general use are lacking. The homeopathic medicine Apis mellifica, advised in anaphylaxis from honeybee sting, is proposed to address the life-threatening dengue shock syndrome, which develops from dengue hemorrhagic fever and has features of anaphylaxis. In both dengue and anaphylaxis, immunoglobulin E activates, and released vasoactive mediators (importantly histamine, tryptase and platelet-activating factor) cause, a vascular permeability enabling shock. In dengue, another mechanism, namely antibody-dependent enhancement, due to secondary infection with a heterologous dengue serotype, is associated with release of vasoactive mediators. The homeopathic medicine Apis mellifica indicates plasma leak, shock, and the serous effusion that is noted in dengue patients, and is a suggested prophylactic and therapeutic medicine for dengue shock syndrome.

Bee Venom-A Potential Complementary Medicine Candidate for SARS-CoV-2 Infections

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is characterized by severe cytokine storm syndrome following inflammation. SARS-CoV-2 directly interacts with angiotensin-converting enzyme 2 (ACE-2) receptors in the human body. Complementary therapies that impact on expression of IgE and IgG antibodies, including administration of bee venom (BV), have efficacy in the management of arthritis, and Parkinson's disease. A recent epidemiological study in China showed that local beekeepers have a level of immunity against SARS-CoV-2 with and without previous exposure to virus. BV anti-inflammatory properties are associated with melittin and phospholipase A2 (PLA2), both of which show activity against enveloped and non-enveloped viruses, including H1N1 and HIV, with activity mediated through antagonist activity against interleukin-6 (IL-6), IL-8, interferon-γ (IFN-γ), and tumor necrosis factor-α (TNF-α). Melittin is associated with the underexpression of proinflammatory cytokines, including nuclear factor-kappa B (NF-κB), extracellular signal-regulated kinases (ERK1/2), and protein kinase Akt. BV therapy also involves group III secretory phospholipase A₂ in the management of respiratory and neurological diseases. BV activation of the cellular and humoral immune systems should be explored for the application of complementary medicine for the management of SARS-CoV-2 infections. BV "vaccination" is used to immunize against cytomegalovirus and can suppress metastases through the PLA2 and phosphatidylinositol-(3,4)-bisphosphate pathways. That BV shows efficacy for HIV and H1NI offers opportunity as a candidate for complementary therapy for protection against SARS-CoV-2.

Methods of Honey Bee Stinger Removal: A Systematic Review of the Literature

Honey bee envenomations are a common occurrence and cause localized morbidity but rarely cause systemic symptoms or death in humans. Honey bee stingers have a uniquely designed venom sac with a piston-containing bifurcated stinger that can remain in human skin and continue injecting venom after stinging. For some time, it has been proposed that a retained honey bee stinger should be scraped out by a dull edge, as opposed to pinching and pulling out the stinger, in order to minimize the volume of venom injected. We undertook a literature review to evaluate the evidence regarding the effectiveness and safety of methods of honey bee stinger removal. The initial search identified 23 articles of interest; following title and abstract screening, two studies met the inclusion criteria. The included articles used different methods and models to evaluate the relationship between venom injection over time, and one of these studies also compared different methods of stinger removal. The literature review was limited by the small number of studies on the topic, but both included studies include findings relevant to the clinical question of interest. Based on the available evidence, a retained honey bee stinger should be removed as quickly as possible, and there appears to be no disadvantage in doing it by pinching and pulling.

Bee Updated: Current Knowledge on Bee Venom and Bee Envenoming Therapy

Honey bees can be found all around the world and fulfill key pollination roles within their natural ecosystems, as well as in agriculture. Most species are typically docile, and most interactions between humans and bees are unproblematic, despite their ability to inject a complex venom into their victims as a defensive mechanism. Nevertheless, incidences of bee stings have been on the rise since the accidental release of Africanized bees to Brazil in 1956 and their subsequent spread across the Americas. These bee hybrids are more aggressive and are prone to attack, presenting a significant healthcare burden to the countries they have colonized. To date, treatment of such stings typically focuses on controlling potential allergic reactions, as no specific antivenoms against bee venom currently exist. Researchers have investigated the possibility of developing bee antivenoms, but this has been complicated by the very low immunogenicity of the key bee toxins, which fail to induce a strong antibody response in the immunized animals. However, with current cutting-edge technologies, such as phage display, alongside the rise of monoclonal antibody therapeutics, the development of a recombinant bee antivenom is achievable, and promising results towards this goal have been reported in recent years. Here, current knowledge on the venom biology of Africanized bees and current treatment options against bee envenoming are reviewed. Additionally, recent developments within next-generation bee antivenoms are presented and discussed.

Immunology of Bee Venom

Bee venom is a blend of biochemicals ranging from small peptides and enzymes to biogenic amines. It is capable of triggering severe immunologic reactions owing to its allergenic fraction. Venom components are presented to the T cells by antigen-presenting cells within the skin. These Th2 type T cells then release IL-4 and IL-13 which subsequently direct B cells to class switch to production of IgE. Generating venom-specific IgE and crosslinking FcεR1(s) on the surface of mast cells complete the sensitizing stage in allergic individuals who are most likely to experience severe and even fatal allergic reactions after being stung. Specific IgE for bee venom is a double-edged sword as it is a powerful mediator in triggering allergic events but is also applied successfully in diagnosis of the venom allergic patient. The healing capacity of bee venom has been rediscovered under laboratory-controlled conditions using animal models and cell cultures. The potential role of enzymatic fraction of bee venom including phospholipase A2 in the initiation and development of immune responses also has been studied in numerous research settings. Undoubtedly, having insights into immunologic interactions between bee venom components and innate/specific immune cells both locally and systematically will contribute to the development of immunologic strategies in specific and epitope-based immunotherapy especially in individuals with Hymenoptera venom allergy.

Ultrastructural analysis of early toxic effects produced by bee venom phospholipase A2 and melittin in Sertoli cells in rats

In this study, we aimed to investigate the testicular toxicity of two molecules derived from bee venom (BV): phospholipase A2 (PlA2) and melittin (Mlt). Ultrastructural effects of purified BV PlA2 and Mlt were assessed consecutive to repeated dose (30 days) and acute toxicity studies. For the subchronic treatment, PlA2 and Mlt were injected in daily doses equivalent to those released by a bee sting (105 μg PlA2/kg/day and 350 μg Mlt/kg/day), while in the acute treatment their doses corresponded to those released by 100 bee stings (9.3 mg PlA2/kg and 31 mg Mlt/kg). Both PlA2 and Mlt affected the Leydig cells and the cells in seminiferous tubules, the Sertoli cells first of all. PlA2 injection resulted in detachment of the Sertoli cells from the surrounding cells, and extracellular vacuolations, cytoplasmic vacuolations in their basal region and in branches as well, detachment of spermatids, residual bodies and sometimes even spermatocytes into the lumen, changes that had a higher magnitude after the acute treatment. Mlt injection induced similar ultrastructural alterations, but more severe, including degeneration of cellular organelles and cellular necrosis, resulting into rarefaction of the seminiferous epithelium; the ultrastructural changes had a higher magnitude after the 30 repeated dose treatment. We concluded that either of the two molecules tested here, PlA2 and Mlt, were Sertoli cells toxicants at the used doses, and they participated both in the BV testicular toxicity. We consider the observed changes as part of a preceding mechanism of the more severe alterations produced by the BV. It also remains possible that these early unspecific changes reported here could represent the response of the SCs not only to the components of bee venom, but to molecules of other venoms as well. The Sertoli cells were the primary target of PlA2 and Mlt in the spermatogenic epithelium, and their alteration led to further degenerative changes of the germ cells. Since the exposure to PlA2 and Mlt caused severe alteration, including cell death and detachment of immature germ cells into the lumen, we may also conclude that the bee venom molecules had a potential to interfere with normal progression of spermatogenesis. All the degenerative changes observed in the Sertoli cells were accompanied with changes of the Leydig cells.

Diversity and human perceptions of bees (Hymenoptera: Apoidea) in Southeast Asian megacities

Urbanization requires the conversion of natural land cover to cover with human-constructed elements and is considered a major threat to biodiversity. Bee populations, globally, are under threat; however, the effect of rapid urban expansion in Southeast Asia on bee diversity has not been investigated. Given the pressing issues of bee conservation and urbanization in Southeast Asia, coupled with complex factors surrounding human-bee coexistence, we investigated bee diversity and human perceptions of bees in four megacities. We sampled bees and conducted questionnaires at three different site types in each megacity: a botanical garden, central business district, and peripheral suburban areas. Overall, the mean species richness and abundance of bees were significantly higher in peripheral suburban areas than central business districts; however, there were no significant differences in the mean species richness and abundance between botanical gardens and peripheral suburban areas or botanical gardens and central business districts. Urban residents were unlikely to have seen bees but agreed that bees have a right to exist in their natural environment. Residents who did notice and interact with bees, even though being stung, were more likely to have positive opinions towards the presence of bees in cities.

Scorpion sting nephropathy

Scorpion envenomations are ubiquitous, but nephropathy is a rare manifestation, reported mainly from the Middle East and North Africa. Rapid venom redistribution from blood, delayed excretion from the kidneys, direct toxicity of venom enzymes, cytokine release and afferent arteriolar constriction have been seen in experimental animals. Haemoglobinuria, acute tubular necrosis, interstitial nephritis and haemolytic–uraemic syndrome have been documented in human victims of scorpion envenomation. Epidemiology, venom components and toxins, effects on the laboratory mammals especially the kidneys and reports of renal failure in humans are reviewed in this article.

Laboratory identification of arthropod ectoparasites

The collection, handling, identification, and reporting of ectoparasitic arthropods in clinical and reference diagnostic laboratories are discussed in this review. Included are data on ticks, mites, lice, fleas, myiasis-causing flies, and bed bugs. The public health importance of these organisms is briefly discussed. The focus is on the morphological identification and proper handling and reporting of cases involving arthropod ectoparasites, particularly those encountered in the United States. Other arthropods and other organisms not of public health concern, but routinely submitted to laboratories for identification, are also briefly discussed.

Acute kidney injury due to acute cortical necrosis following a single wasp sting

Acute kidney injury (AKI) can develop after multiple wasp or bee stings. The etiology is the acute tubular necrosis secondary to shock, pigment toxicity, interstitial nephritis, or direct nephrotoxicity of venom. We report a 40-year-old female who presented with oliguric AKI after a single wasp sting on her hand. Her history, examination, and investigations did not support any of the established causes of AKI in such settings. She did not improve with supportive management and dialysis, and kidney biopsy showed acute cortical necrosis (ACN). This is the first report of ACN after a single wasp sting.

Fatal Envenomations - Snakes and Other Creatures

Envenomations by toxic creatures is a global health problem with an annual mortality from snake envenomation of over 125,000 cases. While various snake species bites are the most commonly encountered fatal envenomation, scorpions, spiders and marine creatures can all cause fatalities. Although venomous creatures have specific geographical habitats, the keeping of exotic pets and modern transportation, along with venomous collections in zoos, means that fatal envenomations may be encountered in non-endemic areas. There are a variety of toxins that may be encountered including neurotoxins, proteases, and myotoxins that will result in a variable amount of tissue damage depending upon the species involved and the toxin they carry. The autopsy findings may be relatively nonspecific and a careful search of the skin may be required to identify the envenomation site, along with a consideration of the history and the scene. External and internal damage will vary with the specific toxin. This paper reviews fatal envenomations, the toxinology and likely autopsy findings.

Bee (Apis mellifera) venom produced toxic effects of higher amplitude in rat thoracic aorta than in skeletal muscle--an ultrastructural study

In this study, changes produced in aorta and triceps surae muscle of Wistar rats as response to bee venom (BV) envenomation were analyzed by transmission electron microscopy and morphometry. A subchronic treatment of 30 days with daily doses of 700 μg BV/kg and an acute-lethal treatment with a single dose of 62 mg BV/kg were performed. The subchronic treatment resulted in endothelial cell retraction, a thicker subendothelial layer, and thinner elastic laminae and musculoelastic layers in aorta, and thicker endothelium and basal laminae in skeletal muscle. In both tissues polymorphous, swollen mitochondria with disrupted cristae were observed. The acute treatment produced extensive endothelial lesions, breakdown of the collagen layer and migration of muscle cells toward the intima in the aorta, and dilatation of endoplasmic reticulum in the skeletal muscle cells. Mitochondria were almost devoid of cristae or with few circular cristae in the smooth muscle cells while most of the mitochondria presented abnormal circular cristae in the skeletal muscle cells. Degenerative alterations in the aorta were of higher intensity in our experiments-both the intima and media strongly responded to BV, in contrast to those found at the level of the skeletal muscle cells where a moderate degenerative myopathy was recorded.

Acute renal failure following multiple hornet stings

Hornet stings are medically important stings which can cause allergic manifestations and, in severe cases, may lead to the unusual complication of acute renal failure (ARF) and other systemic complications. ARF results from toxic or ischaemic acute tubular necrosis in a setting of haemolysis or rhabdomyolysis or both and acute allergic interstitial nephritis. Venom from hornet stings can also contribute to myocardial injury or liver impairment. Here, we report three cases of hornet stings leading to ARF. Case #1 and Case #3 recovered their renal function and body physiology after a 38-day and 15-day stay in the hospital, respectively, whereas Case #2 died. They were meticulously supported by haemodialysis along with the combination of various drug regimens.

A case of Spider bite localized to the eyelid

Loxosceles Spiders have a worldwide distribution and are considered one of the most medically important groups of Spiders. The venom from Spiders of the genus Loxosceles, the most famous being Loxosceles reclusa (brown recluse Spider), can promote severe local and systemic damages. This report describes a girl presenting with a Spider bite over her right upper eyelid.

Electrophysiological and structural aspects in the frontal cortex after the bee (Apis mellifera) venom experimental treatment

The aim of this study is to evaluate the bioelectrical and structural-functional changes in frontal cortex after the bee venom (BV) experimental treatments simulating both an acute envenomation and a subchronic BV therapy. Wistar rats were subcutaneously injected once with three different BV doses: 700 μg/kg (T(1) group), 2100 μg/kg (T(3) group), and 62 mg/kg (sublethal dose-in T(SL) group), and repeated for 30 days with the lowest dose (700 μg/kg-in T(S) group). BV effects were assessed by electrophysiological, histological, histochemical, and ultrastructural methods. Single BV doses produced discharges of negative and biphasic sharp waves, and epileptiform spike-wave complexes. The increasing frequency of these elements suggested a dose-dependent neuronal hyperexcitation or irritation. As compared to the lower doses, the sublethal dose was responsible for a pronounced toxic effect, confirmed by ultrastructural data in both neurons and glial cells that underwent extensive, irreversible changes, triggering the cellular death. Subchronic BV treatment in T(S) group resulted in a slower frequency and increased amplitude of cortical activity suggesting neuronal loss. However, neurons were still stimulated by the last BV dose. Structural-functional data showed a reduced cellular density in frontal cortex of animals in this group, while the remaining neurons displayed both specific (stimulation of neuronal activity) and unspecific modifications (moderate alterations to necrotic phenomena). Molecular mechanisms involved in BV interactions with the nervous tissue are also discussed. We consider all these data very important for clinicians who manage patients with multiple bee stings, or who intend to set an appropriate BV therapy.

Effects induced by Apis mellifera venom and its components in experimental models of nociceptive and inflammatory pain

The effects induced by Apis mellifera venom (AMV), melittin-free AMV, fraction with molecular mass < 10 kDa (F<₁₀) or melittin in nociceptive and inflammatory pain models in mice were investigated. Subcutaneous administration of AMV (2, 4 or 6 mg/kg) or melittin-free AMV (1, 2 or 4 mg/kg) into the dorsum of mice inhibited both phases of formaldehyde-induced nociception. However, F<₁₀ (2, 4 or 6 mg/kg) or melittin (2 or 3 mg/kg) inhibited only the second phase. AMV (4 or 6 mg/kg), but not F<₁₀, melittin-free AMV or melittin, induced antinociception in the hot-plate model. Paw injection of AMV (0.05 or 0.10 mg), F<₁₀ (0.05 or 0.1 mg) or melittin (0.025 or 0.050 mg) induced a nociceptive response. In spite of inducing nociception after paw injection, scorpion (Tityus serrulatus) or snake (Bothrops jararaca) venom injected into the dorsum of mice did not inhibit formaldehyde-induced nociception. In addition, AMV (6 mg/kg), but not F<₁₀ (6 mg/kg) or melittin (3 mg/kg), inhibited formaldehyde paw oedema. Concluding, AMV, F<₁₀ and melittin induce two contrasting effects: nociception and antinociception. AMV antinociception involves the action of different components and does not result from non-specific activation of endogenous antinociceptive mechanisms activated by exposure to noxious stimuli.

Abnormal mitochondrial cristae were experimentally generated by high doses of Apis mellifera venom in the rat adrenal cortex

In the present study, Apis mellifera venom (AmV) was tested for its ability to cause ultrastructural changes in mitochondria of rat adrenal cortex in vivo. In order to achieve this goal, different AmV treatments were performed and the effects were quantified on transmission electron micrographs. In a first experimental group, AmV injected for 30 days in low daily doses (700 μg/kg) generated important ultrastructural changes in zona fasciculata. The mitochondrial ultrastructure was not affected, but the diameters of mitochondrial cristae (MC) were reduced (57.066 ± 7.795 nm) as compared to the MC diameters in the corresponding control groups (58.596 ± 6.603 nm, and 58.503 ± 5.708 nm). In adrenal glands collected from rats injected with a single, high dose of AmV (62 mg/kg), many ultrastructural changes were described. Mitochondria with normal, tubular MC (with diameter of 58.711 ± 5.907 nm) were observed in many cells, very close to the values calculated for the corresponding control group (58.639 ± 6.117 nm). However, the striking data reported herein concerned the ability of AmV high doses to promote dramatic alterations in the ultrastructure of these particular mitochondria, similar to those described in certain severe diseases. Thus, several types of abnormal mitochondria were observed, including mitochondria displaying lamellar and/or circular, concentric cristae and mitochondria devoid of cristae. The abnormal circular, concentric MC, with large inner (281.904 ± 158.588 nm) and outer (432.076 ± 230.372 nm) diameters, appeared to be the most stable form of MC in the adrenal cortex after the acute treatment with AmV. Among other ultrastructural aspects, these important changes indicated a high level of cytotoxicity of AmV in adrenocortical cells following in vivo experimental poisoning.

Neurotoxic activity and ultrastructural changes in muscles caused by the brown widow spider Latrodectus geometricus venom

Brown widow spider (Latrodectus geometricus) venom (BrWSV) produces few local lesions and intense systemic reactions such as cramps, harsh muscle pains, nausea, vomiting and hypertension. Approximately 16 protein bands under reducing conditions and approximately 14 bands under non-reducing conditions on a 12.5% sodium dodecyl sulfate-polyacrylamide gel electrophoresis were observed. Neurotoxic clinical manifestations were confirmed in vivo, while proteolytic activity was demonstrated on gelatine film. Severe ultrastructural damages in mice skeletal muscles were observed at 3, 6, 12 and 24 h postinjection with at total of 45 microg of venom protein. Infiltration of eosinophils and ruptures of the cellular membranes were observed in the muscles along with swelling of the nuclear cover and interruption of the collagen periodicity. Altered mitochondrias and autophage vacuoles, nuclear indentation and mitochondria without cristae, slight increment of intermyofibrillar and subsarcolemic spaces and myelinic figures formation were also observed. In the capillary, endothelial membrane unfolding into the lumen was noticed; along with myelinic figures compatible with a toxic myopathy. Swollen sarcotubular systems with lysis of membrane, intense mitochondria autophagia and areas without pinocytic vesicles were observed. Swollen mitochondria surrounded by necrotic areas, myofibrillar disorganization and big vacuolas of the sarcotubular system, degenerated mitochondrium with formation of myelinic figure was seen. Glycogenosomes with small particulate, muscle type glycogen was noticed. Autophagic vacuole (autophagolysosomes) and necrotic areas were also noticed. These damages may be due to interactive effects of the multifactorial action of venom components. However, Latrodectus geometricus venom molecules may also be utilized as neuro therapeutic tools, as they affect neuronal activities with high affinity and selectivity. To our knowledge, the present study is the first ultrastructural report in the literature of muscle injuries and neurological and proteolytic activities caused by BrWSV.

NMR-spectroscopic screening of spider venom reveals sulfated nucleosides as major components for the brown recluse and related species

Extensive chemical analyses of spider venoms from many species have revealed complex mixtures of biologically active compounds, of which several have provided important leads for drug development. We have recently shown that NMR spectroscopy can be used advantageously for a direct structural characterization of the small-molecule content of such complex mixtures. Here, we report the application of this strategy to a larger-scale analysis of a collection of spider venoms representing >70 species, which, in combination with mass spectrometric analyses, allowed the identification of a wide range of known, and several previously undescribed, small molecules. These include polyamines, common neurotransmitters, and amino acid derivatives as well as two additional members of a recently discovered family of natural products, the sulfated nucleosides. In the case of the well studied brown recluse spider, Loxosceles reclusa, sulfated guanosine derivatives were found to comprise the major small-molecule components of the venom.

Uninvited "guests" in patient homes

This article reviews commonly prescribed medications used to treat insect bites or stings in a case study format. The review describes the implications of treatment for a patient with chronic kidney disease and acute hepatic obstruction who experienced an insect bite.

Hymenoptera Stings

The medically important groups of Hymenoptera are the Apoidea (bees), Vespoidea (wasps, hornets, and yellow jackets), and Formicidae (ants). These insects deliver their venom by stinging their victims. Bees lose their barbed stinger after stinging and die. Wasps, hornets, and yellow jackets can sting multiple times. Most deaths related to Hymenoptera stings are the result of immediate hypersensitivity reactions, causing anaphylaxis. Massive envenomations can cause death in nonallergic individuals. The estimated lethal dose is approximately 20 stings/kg in most mammals. Anaphylactic reactions to Hymenoptera stings are not dose dependent or related to the number of stings. Bee and wasp venoms are made up primarily of protein. Conversely, fire ant venoms are 95% alkaloids. Four possible reactions are seen after insect stings: local reactions, regional reactions, systemic anaphylactic responses, and less commonly, delayed-type hypersensitivity. Clinical signs of bee and wasp stings include erythema, edema, and pain at the sting site. Occasionally, animals develop regional reactions. Onset of life-threatening, anaphylactic signs typically occur within 10 minutes of the sting. Diagnosis of bee and wasp stings stem from a history of potential contact matched with onset of appropriate clinical signs. Treatment of uncomplicated envenomations (stings) consists of conservative therapy (antihistamines, ice or cool compresses, topical lidocaine, or corticosteroid lotions). Prompt recognition and initiation of treatment is critical in successful management of anaphylactic reactions to hymenopteran stings. Imported fire ants both bite and sting, and envenomation only occurs through the sting. Anaphylaxis after imported fire ant stings is treated similarly to anaphylactic reactions after honeybee and vespid stings. The majority of Hymenopteran stings are self-limiting events, which resolve in a few hours without treatment. Because life-threatening anaphylactic reactions can progress rapidly, all animals stung should be closely monitored and observed. In the following review article, we will examine the sources and incidence, toxicokinetics, pathological lesions, clinical signs, diagnosis, treatment, and prognosis for dogs and cats suffering Hymenoptera stings.

Mechanisms of bee venom-induced acute renal failure

The spread of Africanized bees in the American continent has increased the number of severe envenomation after swarm attacks. Acute renal failure (ARF) is one of the major hazards in surviving patients. To assess the mechanisms of bee venom-induced ARF, rats were evaluated before, up to 70 min and 24h after 0.5mg/kg of venom injection. Control rats received saline. Bee venom caused an early and significant reduction in glomerular filtration rate (GFR, inulin clearance, 0.84+/-0.05 to 0.40+/-0.08 ml/min/100g, p<0.0001) and renal blood flow (RBF, laser Doppler flowmetry), which was more severe in the cortical (-72%) than in the medullary area (-48%), without systemic blood pressure decrease. Creatine phosphokinase, lactic dehydrogenase (LDH) and serum glutamic oxaloacetic transaminase increased significantly, pointing to rhabdomyolysis, whereas serum glutamic pyruvic transaminase and hematocrit remained stable. Twenty-four hours after venom, RBF recovered but GFR remained significantly impaired. Renal histology showed acute tubular injury and a massive tubular deposition of myoglobin. Venom was added to isolated rat proximal tubules (PT) suspension subjected to normoxia and hypoxia/reoxygenation (H/R) for direct nephrotoxicity evaluation. After 60 min of incubation, 0.1, 2 and 10 microg of venom induced significant increases in LDH release: 47%, 64% and 86%, respectively, vs. 21% in control PT while 2 microg of venom enhanced H/R injury (85% vs. 55%, p<0.01). These results indicate that vasoconstriction, direct nephrotoxicity and rhabdomyolysis are important mechanisms in the installation of bee venom-induced ARF that may occur even without hemolysis or hypotension.

Avoidance of bee and wasp stings: an entomological perspective

PURPOSE OF REVIEW

Clinicians and researchers in allergy and immunology are often unaware of aspects of stinging insect biology that would be of practical interest to their patients. This review discusses entomological literature pertaining to avoidance of bee and wasp stings, with emphasis on risk factors associated with provoking individual foragers versus disturbing colonies and preventive measures for both circumstances.

RECENT FINDINGS

Recent work pertaining to sting avoidance has mostly been concerned with the development and testing of attractants, insecticides and delivery systems for toxic baiting programs to control vespine wasps.

SUMMARY

Sting risks and avoidance measures associated with bee and wasp foragers are different from those posed by disturbing colonies. Despite widespread advice to the contrary, no evidence currently exists that wearing perfume or bright, floral-colored clothing elevates sting risk. Foragers usually have to be firmly touched before they will sting; therefore, personal protection largely involves guarding against accidental direct contact. Although still under development, the most effective means for reducing local populations of foraging vespine wasps are toxic baiting programs. Preventing stings from colonies is more problematic and depends mostly on personal awareness when disturbing vegetation. The most effective measure in mitigating the severity of a mass attack is probably the wearing of white or light-colored clothing.

Survey for potentially necrotizing spider venoms, with special emphasis on Cheiracanthium mildei

It has proven difficult to identify those spiders which cause necrotic lesions. In an effort to design a simple, inexpensive screening method for identifying spiders with necrotizing venoms, we have examined the venom gland homogenates of a variety of spider species for their ability to cause red blood cell lysis. Those venoms which were positive were further examined for the presence of sphingomyelinase D, and their ability to evoke necrotic lesions in the skin of rabbits. Sphingomyelinase D is known to be the causative agent of necrosis and red blood cell lysis in the venom of the brown recluse spider (Loxosceles reclusa), and our assumption was that this would be the same agent in other spider venoms as well. This did not prove to be the case. Of 45 species examined, only the venom of L. reclusa and Cheiracanthium mildei lysed sheep red blood cells. Unlike L. reclusa venom, however, C. mildei venom did not possess sphingomyelinase D nor did it cause necrotic lesions in the skin of rabbits. We present evidence suggesting that a phospholipase A2 is the hemolytic agent in C. mildei venom.

Brown spiders and loxoscelism

Accidents caused by brown spiders (Loxosceles genus) are classically associated with dermonecrotic lesions and systemic manifestations including intravascular haemolysis, disseminated intravascular coagulation and acute renal failure. Systemic reactions occur in a minority of cases, but may be severe in some patients and occasionally fatal. The mechanisms by which Loxosceles venom exerts these noxious effects are currently under investigation. The venom contains several toxins, some of which have been well-characterised biochemically and biologically. The purpose of the present review is to describe some insights into loxoscelism obtained over the last ten years. The biology and epidemiology of the brown spider, the histopathology of envenomation and the immunogenicity of Loxosceles venom are reviewed, as are the clinical features, diagnosis and therapy of brown spider bites. The identification and characterisation of some toxins and the mechanism of induction of local and systemic lesions caused by brown spider venom are also discussed. Finally, the biotechnological application of some venom toxins are covered.

Venom effects on monoaminergic systems

The monoamines, dopamine, epinephrine, histamine, norepinephrine, octopamine, serotonin and tyramine serve many functions in animals. Many different venoms have evolved to manipulate monoaminergic systems via a variety of cellular mechanisms, for both offensive and defensive purposes. One common function of monoamines present in venoms is to produce pain. Some monoamines in venoms cause immobilizing hyperexcitation which precedes venom-induced paralysis or hypokinesia. A common function of venom components that affect monoaminergic systems is to facilitate distribution of other venom components by causing vasodilation at the site of injection or by increasing heart rate. Venoms of some scorpions, spiders, fish and jellyfish contain adrenergic agonists or cause massive release of catecholamines with serious effects on the cardiovascular system, including increased heart rate. Other venom components act as agonists, antagonists or modulators at monoaminergic receptors, or affect release, reuptake or synthesis of monoamines. Most arthropod venoms have insect targets, yet, little attention has been paid to possible effects of these venoms on monoaminergic systems in insects. Further research into this area may reveal novel effects of venom components on monoaminergic systems at the cellular, systems and behavioral levels.

The miscellaneous blistering disorders

Historically, the classification of the blistering disorders has been arbitrarily assigned by common clinical features (ie, vesicle, bullae), etiologic factors (ie, infectious, immunologic), or histologic parameters (ie, intraepidermal and subepidermal). There are distinct advantages to each of these classification systems, yet there remain a small number of either common conditions that rarely manifests as a blistering disorder or uncommon conditions that routinely blister, defying conventional classification. Such misfits comprise a miscellaneous group of blistering conditions that merit special consideration.

Sudden unexplained hemolysis occurring in an infant due to presumed Loxosceles envenomation

We report the case of a 3-week-old infant referred for evaluation of sudden onset jaundice and unexplained hemolysis. After an exhaustive workup, the most likely etiology was found to be envenomation by a brown recluse spider, Loxosceles reclusa. This case underscores the fact that severe loxoscelism may occur in the absence of the classically described necrotic cutaneous lesion, and represents one of the youngest presumed cases of loxoscelism. We present the case to illustrate the importance of considering loxoscelism in the differential diagnosis of sudden massive hemolysis in children, particularly in endemic areas of the midwestern and southern United States.

Latrodectism: a prospective cohort study of bites by formally identified redback spiders

OBJECTIVE

To determine the spectrum of severity and early diagnostic predictors of redback spider bites (Latrodectus hasselti), and to examine the effect of intramuscular redback antivenom.

DESIGN AND SETTING

Prospective cohort study of calls to New South Wales, Queensland and Western Australian poisons information centres and presentations to Royal Prince Alfred Hospital and Royal Darwin Hospital emergency departments.

PATIENTS

68 people with definite redback spider bites in which the spider was immediately collected and expertly identified (1 February 1999 to 30 April 2002).

INTERVENTIONS

Intramuscular redback spider antivenom in a smaller cohort of hospitalised patients.

MAIN OUTCOME MEASURES

Pain severity and duration, local effects and systemic envenomation (effects, prevalence, and persistence > 24 hours).

RESULTS

The median duration of effects was 48 hours (interquartile range, 24-96 hours). Pain occurred after all bites and was severe in 42 (62%). Forty-five patients (66%) had pain lasting longer than 24 hours, and 22 (32%) were unable to sleep because of pain. Systemic effects occurred in 24 (35%). Increasing pain over one hour occurred in 37 cases (54%), and local/regional diaphoresis in 23 (34%); both these features were highly predictive of L. hasselti bites compared with bites of other spiders. One of six patients treated with intramuscular antivenom (17%) had no pain at 24 hours, compared with two of 17 untreated patients (12%) (difference, 5%; 95% CI, -36% to +64%; P = 0.95). There was no difference in duration of systemic effects with antivenom administration.

CONCLUSIONS

Most redback spider bites cause severe and persistent effects. Intramuscular antivenom appears to be less effective than previously thought and its use by this route needs review.

Distribution of the medically-implicated hobo spider (Araneae: Agelenidae) and a benign congener, Tegenaria duellica, in the United States and Canada

The hobo spider, Tegenaria agrestis (Walckenaer), and the related Tegenaria duellica Simon are very similar European spiders that have become well established in the northwestern United States and British Columbia. The hobo spider is considered to be medically important; T. duellica is considered harmless but is often misidentified as the hobo spider. The current distribution of the hobo spider includes southern British Columbia, Washington, Oregon, Idaho, northern Utah, the western half of Montana, western Wyoming, and two small, isolated populations in Colorado. T. duellica is found mostly west of the Cascade and Coastal mountain ranges from southern British Columbia to central Oregon. In large human population centers where both species are sympatric, T. duellica is usually more common than the hobo spider. Data from a total of 1,232 hobo spiders and 395 T. duellica are included in this study.

Bites by spiders of the family Theraphosidae in humans and canines

Spiders of the family Theraphosidae occur throughout most tropical regions of the world. There have only been three case reports of bites by these spiders in Australia. The aim of this study was to describe the clinical effects of bites by Australian theraphosid spiders in both humans and canines. Cases of spider bite were collected by the authors over the period January 1978-April 2002, either prospectively in a large study of Australian spider bites, or retrospectively from cases reported to the authors. Subjects were included if they had a definite bite and had collected the spider. The spiders were identified by an expert arachnologist to genus and species level where possible. There were nine confirmed bites by spiders of the family Theraphosidae in humans and seven in canines. These included bites by two Selenocosmia spp. and by two Phlogiellus spp. The nine spider bites in humans did not cause major effects. Local pain was the commonest effect, with severe pain in four of seven cases where severity of pain was recorded. Puncture marks or bleeding were the next most common effect. In one case the spider had bitten through the patient's fingernail. Mild systemic effects occurred in one of nine cases. There were seven bites in dogs (Phlogellius spp. and Selenocosmia spp.), and in two of these the owner was bitten after the dog. In all seven cases the dog died, and as rapidly as 0.5-2h after the bite. This small series of bites by Australian theraphosid spiders gives an indication of the spectrum of toxicity of these spiders in humans. Bites by these spiders are unlikely to cause major problems in humans. The study also demonstrates that the venom is far more toxic to canines.

An infestation of 2,055 brown recluse spiders (Araneae: Sicariidae) and no envenomations in a Kansas home: implications for bite diagnoses in nonendemic areas

During a 6-mo period, 2,055 brown recluse spiders, Loxosceles reclusa Gertsch and Mulaik, were collected in a 19th-century-built, currently occupied home in Lenexa, KS. We conservatively estimate that at least 400 of these spiders were large enough to cause envenomation. Additional collections from more typically infested homes in Missouri and Oklahoma in 2001 yielded 45 and 30 brown recluse spiders, respectively. Despite these infestations, no envenomations of the inhabitants of these three homes occurred. Considering the levels of infestations with no bites in the homes presented here, nonendemic areas in the United States, which typically lack recluse spider populations and have had zero to few verified specimens of the spider, do not have sufficient numbers of brown recluse spiders to make envenomation a likely scenario. Despite this, physicians from nonendemic recluse areas often diagnose brown recluse bites which, therefore, are unlikely to be correct.

[Biceps crural myositis after an insect bite]

INTRODUCTION

It can be difficult to diagnose focal muscular disease. We report a case of crural biceps focal myositis after an insect bite.

DISCUSSION

We then discuss diagnostics of one or a small number of muscle injury. Focal inflammatory myositis has been described. We emphasize the role of pathology. In our case, pathological examination rules out inflammatory or tumoral disease and access likely toxical etiology. Muscle injury can appear, most frequently around the bite of venomous animal.

CONCLUSION

Hymenopters are often responsible for such stings in France. Venoms are toxic for muscle cells membrane.

Reports of presumptive brown recluse spider bites reinforce improbable diagnosis in regions of North America where the spider is not endemic

Envenomations by the brown recluse spider have been reported throughout North America, despite the fact that the spider's range is limited to the South and central Midwest of the United States. Several of these medical reports have originated from regions of nonendemicity where the spider has never or rarely been documented and brown recluse spider populations are unknown. In most of these reports, no spider is positively identified in association with the dermonecrotic wound, and diagnosis has been based on clinical examination findings. Considering the extreme rarity of brown recluse spiders in areas of nonendemicity, the diagnosis of a presumptive bite is a misdiagnosis that reinforces the assumption that brown recluse spiders are common local etiologic agents of necrosis. There are many medical conditions of diverse origin that have been misdiagnosed as brown recluse spider bites, some of which can be fatal or debilitating. Physicians' awareness of these conditions will increase diagnostic accuracy in areas of North America where bites from brown recluse spiders are improbable.

An autopsy approach to bee sting-related deaths

Although severe reactions to the sting of the common honey bee (Apis mellifera) are a common problem in Australia, reported deaths are uncommon, with the estimated mortality varying from one to four persons each year. The following study presents the postmortem findings in three cases of bee sting fatality, including one in which no observable sting was found. An autopsy approach to such cases is detailed. Overreporting of bee sting-related deaths may occur due to the inclusion of deaths unrelated to a reaction to bee venom, while under-reporting may be due to unexplained deaths where a history of a bee sting is not available or apparent at autopsy. A classification of bee sting-related deaths is proposed, which would allow more accurate reporting of bee sting-related fatalies. A serum tryptase and specific IgE to bee venom on serum obtained at autopsy can assist in confirming anaphylactic reaction to bee venom as the cause of death, particularly in the absence of observable stings. Although there are limitations to the usefulness of serum tryptase tests in the postmortem situation, it may still be useful to confirm suspected anaphylaxis in autopsy cases with an undetermined cause of death.

An analysis of geographic and intersexual chemical variation in venoms of the spider Tegenaria agrestis (Agelenidae)

The spider Tegenaria agrestis is native to Europe, where it is considered medically innocuous. This species recently colonized the US where it has been accused of bites that result in necrotic lesions and systemic effects in humans. One possible explanation of this pattern is the US spiders have unique venom characteristics. This study compares whole venoms from US and European populations to look for unique US characteristics, and to increase our understanding of venom variability within species. This study compared venoms from T. agrestis males and females from Marysville, Washington (US), Tungstead Quarry, England (UK) and Le Landeron, Switzerland, by means of liquid chromatography; and the US and UK populations by insect bioassays. Chromatographic profiles were different between sexes, but similar within sexes between US and UK populations. Venoms from the Swiss population differed subtly in composition from UK and US venoms. No peaks were unique to the US population. Intersexual differences were primarily in relative abundance of components. Insect assays revealed no differences between US and UK venom potency, but female venoms were more potent than male. These results are difficult to reconcile with claims of necrotic effects that are unique to venoms of US Tegenaria.