Brown spiders (Loxosceles) are taking hold in Pernambuco, Brazil: a case series, 2018-2022

OBJECTIVE

To describe accidents involving brown spider (genus Loxosceles) bites notified by the Pernambuco Poison Information and Care Center (CIATox-PE), Brazil, from January 2018 to December 2022.

METHODS

This was a case series study of brown spider bites notified by the CIATox-PE.

RESULTS

The study included 22 cases with median age of 35 years, the majority being female (13); the cases occurred in rural and urban areas (12 versus 10), at night (10); Petrolina was the municipality with the highest number of notifications (6); spider bites occurred mainly in the lower (11) and upper (9) limbs, almost exclusively inside households (21); specific serum therapy was not indicated for 8 cases because the time for its effectiveness had already elapsed.

CONCLUSION

Loxoscelism cases occurred more frequently in females, in both rural and urban areas and mainly at home, with delays in seeking medical care.

MAIN RESULTS

The 22 cases described represent an alert for the presence of a venomous species not reported in previous studies in Pernambuco. The severity of cases may be associated with delays in seeking medical care, especially due to the population's lack of information.

IMPLICATIONS FOR SERVICES

Identify the presence of brown spiders in households in the region and the potential severity of poisonings. Alert health professionals to recognize the clinical picture with a view to appropriate early treatment.

PERSPECTIVES

Develop research on poisoning by venomous animals and educational actions alerting the population to prevent these accidents and updating health professionals on care.

Spider bites in France: Epidaemiology of cases occurring in 10 years in metropolitan France

Spiders are often wrongly designated as responsible for cutaneous eruptions. We aim to describe spider bites and the spider species implicated in metropolitan France. A retrospective observational study was conducted for all reported cases of spider bites from 2007 to 2018 extracted from the French Poison Control Centers (PCCs) information system, after exclusion of non-native spiders. We described identification of the spider, level of certainty of the bite, symptoms and severity of cases. 1194 cases of spider bites met the inclusion criteria. The average age of the patients was 36.9 ± 19.8 years. Identification of the species or at least that a spider was implicated was only possible in 346 cases (29.0%). Loxosceles were involved in 53 cases (4.4%), Latrodectus in 46 cases (3.9%) and Cheiracanthium in 35 cases (2.9%). In one third of cases, the involved spider was not known to be present where the bite occurred. Where most of the patients (n = 1111, 93%) reported at least one cutaneous symptom, most of the symptoms were neurological. The bite was considered proven in only 242 cases (20%). Despite the efforts of arachnologists to educate the public, the fear of spiders is still alive in France, where spider bite is rare with low severity and often unproven.

A Review of Black Widow (Araneae: Theridiidae) Envenomation, Epidemiology, and Antivenom Utilization in Canada

Two species of black widow spider (BWS-Latrodectus hesperus Chamberlin & Ivie and Latrodectus variolus Walckenaer) naturally occur in Canada and are capable of causing deleterious envenomation to humans. No Canadian literature exists on the frequency of envenomations by these species or the use of antivenom in the treatment of those patients. A review of primary Canadian arachnology data was undertaken to identify BWS populations. A retrospective review of the Health Canada Special Access Program records generated epidemiology and the utilization of antivenom for BWS envenomations in Canada. The geographical distribution of BWS species is limited to along the southern Canadian border. From January 2009 to December 2015, there were five BWS envenomations that required treatment with antivenom and all cases occurred in British Columbia. An average patient age of 41 yr ± 21 SD (range 7-59) was observed, along with three of the five patients being female. The average number of vials used for treatment was 2 ± 1 SD (range 1-3). BWS Antivenin was also obtained by facilities in Alberta, Ontario, and Nova Scotia, but not used in any of these jurisdictions. Further investigation is necessary to determine the annual incidence of BWS envenomations and if treatment with BWS antivenin is required.

Clinical aspects, diagnosis and management of Loxosceles spider envenomation: literature and case review

The genus Loxosceles comprises 140 species widely distributed around the world. These spiders are nocturnal, sedentary and remarkably nonaggressive, although they cause accidents in humans with wide degrees of severity, generating signs and symptoms that define the clinical condition known as loxoscelism. Its local signs and symptoms were first reported in 1872, and over the years, a large medical literature has been accumulated; unfortunately, it is not always trustworthy. Assessing the reliability of such information, we reviewed 120 case reports of loxoscelism published in 84 articles over the past 20 years. This search allowed us to gather information on the clinical aspects, diagnosis and treatment of loxoscelism, showing that the severity of these accidents has multiple degrees and that it is influenced by many factors. Thus, coupled with epidemiological and species occurrence information, this study can be a useful tool for the clinical practice of loxoscelism. It may support and provide a multidisciplinary view that should be taken into consideration when establishing the therapeutic approach in cases of Loxosceles envenomation.

Matching global and regional distribution models of the recluse spider Loxosceles rufescens: to what extent do these reflect niche conservatism?

The Mediterranean recluse spider, Loxosceles rufescens (Dufour, 1820) (Araneae: Sicariidae) is a cosmopolitan spider that has been introduced in many parts of the world. Its bite can be dangerous to humans. However, the potential distribution of this alien species, which is able to spread fairly quickly with human aid, is completely unknown. Using a combination of global and regional niche models, it is possible to analyse the spread of this species in relation to environmental conditions. This analysis found that the successful spreading of this species varies according to the region invaded. The majority of populations in Asia are stable and show niche conservatism, whereas in North America this spider is expected to be less successful in occupying niches that differ from those in its native region and that do not support its synanthropic way of living.

Niche modelling of the Chilean recluse spider Loxosceles laeta and araneophagic spitting spider Scytodes globula and risk for loxoscelism in Chile

In Chile, all necrotic arachnidism is attributed to the Chilean recluse spider Loxosceles laeta (Nicolet) (Araneae: Sicariidae). It is predated by the spitting spider Scytodes globula (Nicolet) (Araneae: Scytodidae). The biology of each of these species is not well known and it is important to clarify their distributions. The aims of this study are to elucidate the variables involved in the niches of both species based on environmental and human footprint variables, and to construct geographic maps that will be useful in estimating potential distributions and in defining a map of estimated risk for loxoscelism in Chile. Loxosceles laeta was found to be associated with high temperatures and low rates of precipitation, whereas although S. globula was also associated with high temperatures, its distribution was associated with a higher level of precipitation. The main variable associated with the distribution of L. laeta was the human footprint (48.6%), which suggests that this is a highly invasive species. Similarly to other species, the distribution of L. laeta reaches its southern limit at the Los Lagos region in Chile, which coincides with high levels of precipitation and low temperatures. The potential distribution of L. laeta in Chile corresponds to the distribution of cases of loxoscelism.

Low Health System Performance, Indigenous Status and Antivenom Underdosage Correlate with Spider Envenoming Severity in the Remote Brazilian Amazon

Background

A better knowledge of the burden and risk factors associated with severity due to spider bites would lead to improved management with a reduction of sequelae usually seen for this neglected health problem, and would ensure proper use of antivenoms in remote localities in the Brazilian Amazon. The aim of this study was to analyze the profile of spider bites reported in the state of Amazonas in the Western Brazilian Amazon, and to investigate potential risk factors associated with severity of envenomation.

Methodology/Principal Findings

We used a case-control study in order to identify factors associated with spider bite severity in the Western Brazilian Amazon from 2007 to 2014. Patients evolving to any severity criteria were considered cases and those with non-severe bites were included in the control group. All variables were retrieved from the official Brazilian reporting systems. Socioeconomical and environmental components were also included in a multivariable analysis in order to identify ecological determinants of incidence and severity. A total of 1,181 spider bites were recorded, resulting in an incidence of 4 cases per 100,000 person/year. Most of the spider bites occurred in males (65.8%). Bites mostly occurred in rural areas (59.5%). The most affected age group was between 16 and 45 years old (50.9%). A proportion of 39.7% of the bites were related to work activities. Antivenom was prescribed to 39% of the patients. Envenomings recorded from urban areas [Odds ratio (OR) = 0.40 (95%CI = 0.30–0.71; p<0.001)] and living in a municipality with a mean health system performance index (MHSPI >median [OR = 0.64 (95%CI = 0.39–0.75; p<0.001)] were independently associated with decreased risk of severity. Work related accidents [OR = 2.09 (95%CI = 1.49–2.94; p<0.001)], Indigenous status [OR = 2.15 (95%CI = 1.19–3.86; p = 0.011)] and living in a municipality located >300 km away from the state capital Manaus [OR = 1.90 (95%CI = 1.28–2.40; p<0.001)] were independently associated with a risk of severity. Living in a municipality located >300 km away from the state capital Manaus [OR = 1.53 (95%CI = 1.15–2.02; p = 0.003)] and living in a municipality with a MHSPI <median [OR = 1.91 (95%CI = 1.28–2.47; p = 0.002)] increased the odds of antivenom underdosage.

Conclusions

Spider bites is prevalent across the study region with a higher incidence in the rainy season in rural areas. Spider bites can be painful and lead to local manifestations but rarely result in life-threatening envenoming. Major local complications were dermonecrosis and secondary infection in cases diagnosed as Loxosceles bites. Based on the correlations shown here, envenomings occurring in remote rural areas, Indigenous status and living in a municipality located >300 km away from the state capital Manaus could be contributing factors to higher severity of spider envenomings in this area, as well as to antivenom underdosage.

Envenomation by Trachelas tranquillus (Araneae: Corrinidae) in Connecticut

We report a case of envenomation by Trachelas tranquillus (Hentz) in Connecticut in late September 2013. The bitten subject, a 50 yr-old-female Caucasian, reported a painful wasp-like sting and brushed the spider from her leg. An erythematous macule formed at the site of the bite. The macule was gone by the next day and there was no associated necrosis. The spider was collected and brought to our laboratory for identification. This is the second confirmed case of envenomation by T. tranquillus and the only case reported from Connecticut.

Bites and stings: epidemiology and treatment

Rapid and effective treatment of bites is a major variable in the overall outcome of a patient who is a victim of a bite. There are a wide range of animals that bite and sting, and the reactions vary depending on the individual and the animal involved. Although most bites are treated on an outpatient basis, patients who have severe complications related to bites become patients in critical care settings. An overview of potential bite and sting sources, with some general guidelines for what to expect and how to treat the patient, is presented.

[Overall pattern of accidents caused by poisonous animals in Colombia, 2006-2010]

OBJECTIVE

This study was motivated as only partial knowledge is available (regarding national statistics) about accidents caused by poisonous animals in Colombia. The study was aimed at establishing a base-line concerning accidents reported by phone to the Toxicology Management and Research Information Centre (CIGITOX) from all over Colombia; such data was taken from the centre's data-base following its five years of being in operation(2006-2010).

METHODS

This was a descriptive, retrospective study, taking information from the CIGITOX database over a five-year period (2006-2010); Excel 2011was used for statistical analysis.

RESULTS

The database contained 1,783 cases which had been reported and attended; 47 % concerned snake bite accidents (an obligatory report event in Colombia), 25 % scorpion stings and 11 % spider bites, followed by others having valuable epidemiologic representation in the main areas of occurrence, such as the Antioquia, Valle del Cauca and Cundinamarca departments.

DISCUSSION

The data provided an overview of the situation which could lead to promoting public health program aimed at raising awareness in communities, institutions and healthcare professional's whilst enforcing their ability to respond effectively.

Spider bite

Spiders are a source of intrigue and fear, and several myths exist about their medical effects. Many people believe that bites from various spider species cause necrotic ulceration, despite evidence that most suspected cases of necrotic arachnidism are caused by something other than a spider bite. Latrodectism and loxoscelism are the most important clinical syndromes resulting from spider bite. Latrodectism results from bites by widow spiders (Latrodectus spp) and causes local, regional, or generalised pain associated with non-specific symptoms and autonomic effects. Loxoscelism is caused by Loxosceles spp, and the cutaneous form manifests as pain and erythema that can develop into a necrotic ulcer. Systemic loxoscelism is characterised by intravascular haemolysis and renal failure on occasion. Other important spiders include the Australian funnel-web spider (Atrax spp and Hadronyche spp) and the armed spider (Phoneutria spp) from Brazil. Antivenoms are an important treatment for spider envenomation but have been less successful than have those for snake envenomation, with concerns about their effectiveness for both latrodectism and loxoscelism.

Spider bites - Assessment and management

BACKGROUND

Spider bite is common, but most species cause minimal or no effects. Patients may be misinformed regarding the nature and consequences of a bite. Understanding the current literature can assist the physician in the management of spider bite patients.

OBJECTIVE

This article reviews the current literature on spider bites and describes the clinical assessment and management of the medically important spider bites.

DISCUSSION

Most spider bite is minor and causes nothing more than local irritation. Some spiders can cause significant morbidity and rarely, mortality. Lay identification of the spider has not been shown to be reliable. Latrodectism (red back spider envenomation) is characterised by pain (local, radiating, and regional); systemic symptoms occur less commonly. Funnel web spider bite is a medical emergency; a pressure immobilisation bandage should be applied and the patient transferred to a hospital with available antivenom and resuscitation facilities. Clinicians must consider spider bite in the differential diagnosis of unexplained autonomic and neurological dysfunction, particularly in children. In Australia, skin ulceration is more likely to be an infective, inflammatory or traumatic cause than a case of necrotising arachnidism.

Spider poisoning: a report of six cases from the Central Anatolian region, Turkey

Spiders exist in every place and ecosystem. Spiders in tropical regions are particularly poisonous and can be dangerous to humans. Nearly 20,000 spider species are known, and almost all are venomous, although only 60 species worldwide are poisonous in humans. In our area, eight species are reported as poisonous in humans. Although most cases of spider bite are benign and require no intervention, severe local and systemic reactions may occur sometimes in the pediatric population, resulting in admission to the pediatric intensive care unit. In this report, we present the cases of six children from the Central Anatolian region in Turkey who were seriously affected by spider bites, and we review the literature on spider envenomation.

New Zealand's venomous creatures

AIM

New Zealand is home to a small number of venomous creatures. The purpose of this review is to educate and update healthcare professionals on the management of envenoming from these creatures.

METHODS

An extensive literature review was performed by systematically searching OVID MEDLINE and ISI Web of Science. In addition, further information was obtained from book chapters, relevant news reports, and web material.

RESULTS

The signs and symptoms resulting from envenoming of clinically significant venomous creatures found in New Zealand are discussed. Definitive medical treatment recommendations are made.

CONCLUSION

Encounters with New Zealand's few venomous creatures, while rarely fatal, can cause significant morbidity. Effective management can be achieved by informed health professionals having regard to the principles outlined in this review.

Distribution of the brown recluse spider (Araneae: Sicariidae) in Georgia with comparison to poison center reports of envenomations

Georgia is on the southeastern margin of the native range of the brown recluse spider, Loxosceles reclusa Gertsch and Mulaik. The brown recluse is not a common Georgia spider and has limited distribution in the state. Using recent submissions, previously published records, and examination of museum specimens, we document the spider's presence in 31 (19.5%) of Georgia's 159 counties, with almost all being found in the northern portion. The spider was collected almost exclusively north of the Fall Line (a transition zone separating the Piedmont and the Coastal Plain geological provinces). Only two locations in the southern Coastal Plain province produced L. reclusa specimens; these southern finds are considered spiders that were transported outside their range. There were six finds of the non-native world tramp species, L. rufescens (Dufour), three south of the Fall Line. In conspicuous contrast, over a 5-yr period, a Georgia poison center database recorded 963 reports of brown recluse spider bites from 103 counties. These figures greatly outnumber the historic verifications of brown recluses in the state for both specimen quantity and county occurrence, indicating improbable spider involvement and the overdiagnosis of bites. In the southern half of the state, medical diagnoses of brown recluse spider bites have virtually zero probability of being correct. Bite diagnoses should be made with caution in north Georgia given the spider's spotty distribution with low frequency of occurrence.

[Envenomation and poisoning by venomous or poisonous animals. VII: arachnidism in the New World]

The incidence of scorpion stings and spider bites is high in Latin America. This is particularly true for Mexico, part of Amazonia, and southern and eastern Brazil. Centruroides and Tityus scorpion stings present a real danger for humans, especially children. Envenomation results in intense pain, neurological signs, and cardiorespiratory manifestations that can lead to death by acute pulmonary edema or heart failure. In the event of confirmed envenomation, antivenin must be administered as soon as possible in association with symptomatic treatment and, if necessary, cardiorespiratory resuscitation. Spider bites are a less frequent and severe. Envenomation by Loxosceles is extremely painful and necrotizing. Severe visceral complications can develop. An effective antivenim has recently become available for local and systemic envenomation. Envenomation by Latrodectus leads to neurological symptoms that can also be treated with antivenom. Envenomation by other spiders is less frequent and generally harmless.

Medical aspects of spider bites

Spiders have been incriminated as causes of human suffering for centuries, but few species worldwide cause medically significant envenomation. Widow spiders (Latrodectus spp.) occur worldwide and cause latrodectism, which is characterized by pain (local and generalized) associated with nonspecific systemic effects, diaphoresis, and less commonly other autonomic and neurological effects. Recluse spiders (Loxosceles spp.) are distributed mostly through the tropical and subtropical Western Hemisphere and can cause severe skin lesions and rarely systemic effects; most bites are unremarkable. Highly dangerous spiders in South America (armed spiders) and Australia (funnel-web spiders) cause rare but severe envenomation requiring medical intervention and sometimes antivenom. Most other spiders involved in verified bites cause minor, transient effects. Many spiders blamed for causing medical mischief have been elevated to medical significance via circumstantial evidence, poor reporting, and repetitive citation in the literature; several species have been shown to be harmless with more stringent scientific evidence involving verified bites in humans.

Reports of envenomation by brown recluse spiders exceed verified specimens of Loxosceles spiders in South Carolina

PURPOSE

To determine whether the number of brown recluse spider bites diagnosed by South Carolina physicians coincides with evidence of brown recluse spiders found in the state.

METHODS

Brown recluse spider bite diagnosis data were extracted from 1990 and 2004 surveys of South Carolina physicians. This was compared with the known historical evidence of brown recluse spiders collected in South Carolina and derived from various sources, including state agencies, arachnologists, and museum specimens.

RESULTS

South Carolina physicians diagnosed 478 brown recluse spider bites in 1990 and 738 in 2004. Dating to 1953, 44 brown recluse spider specimens have been verified from 6 locations in South Carolina.

DISCUSSION

The number of brown recluse bites reportedly diagnosed in South Carolina greatly outnumbers the verified brown recluse specimens that have been collected in the state. The pattern of bite diagnoses outnumbering verified brown recluse specimens has been reported in other areas outside of this spider's known endemic range.

Of spiders and zebras: publication of inadequately documented loxoscelism case reports

The dermatology and general medical literature is filled with articles that report skin disease caused by the brown recluse spider, Loxosceles reclusa. A large number of these articles contain inadequate documentation of Loxosceles bites; many come from areas that have no Loxosceles spiders. Authors submitting papers alleging loxoscelism should adhere to standards of evidence when writing case reports.

Epidemiology of the brown recluse spider bite

PURPOSE

The purpose of this article was to provide a comprehensive epidemiological and clinical description of the brown recluse spider bite.

DATA SOURCES

Review of evidenced-based scientific literature and practice guidelines. A specific descriptive case study is interwoven through the article to tie in the clinical presenting figure associated with this bite.

CONCLUSIONS

The brown recluse lives in a circumscribed area of the United States (the south central Midwest) with a few less common recluse species living in the more sparsely populated southwest United States. In these areas, where spider populations may be dense, recluse spiders may be a cause of significant morbidity.

IMPLICATIONS FOR PRACTICE

Most spider bites are asymptomatic but what makes this bite so devastating is the toxin injected by the brown recluse spider, which can cause considerable systemic symptoms as well as necrotic skin ulcers (necrotic arachnidism). The article presents process for diagnosis and stresses the importance of identifying the spider if at all possible.

Epidemiological and clinical manifestations of patients hospitalized with brown recluse spider bite

BACKGROUND

Necrotic arachnidism represents a common health problem and standard treatments are usually safe and effective.

OBJECTIVE

The aim of this study was to review documented Loxosceles species spider envenomations and identify the natural history of affected patients.

METHODS

A retrospective single-centre study included 52 patients with necrotic arachnidism hospitalized in the dermatology department between 1997 and 2004. We examined the relationship between the epidemiological, clinical and laboratory parameters and degree of lesion severity, length of hospitalization and time to complete healing.

RESULTS

The bites occurred predominantly in rural areas, 67% between April and August. Only 35% of the patients sought medical care within 24 h post bite. Most bites were of the extremities (67%). Time to complete healing ranged from 14 days to more than 8 weeks (mean, 4.8 weeks). A marked relationship was found between age, comorbidities, lesion severity and time to complete healing (P < 0.01). Duration of hospitalization was significantly longer in patients with severe thigh lesions (P < 0.02).

CONCLUSIONS

Loxosceles species spider bites frequently induce necrotic, slowly healing ulcers on the fatty areas of the body. Early, appropriate systemic therapy may provide clinical benefit.

Skin Lesions in Barracks: Consider Community-Acquired Methicillin-ResistantStaphylococcus aureusInfection Instead of Spider Bites

Recent outbreaks of mysterious skin lesions on multiple personnel at several military facilities were initially blamed on spiders. Requests were made for pest inspection and control to remedy the situation. Greater scrutiny of the situation led to a hypothesis that instead of spiders, an infectious outbreak of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) should be investigated as the etiology. Subsequent culturing of the lesions on personnel at one facility confirmed this bacterial etiology. Barracks, as well as other close quarter military living conditions, are ripe environments for the establishment, persistence, and spread of CA-MRSA. Military medical personnel should consider CA-MRSA as a more likely etiologic agent than spider bites for cutaneous eruptions in which there are multiple lesions on one person or multiple patients with similar lesions.

Verified bites by the woodlouse spider, Dysdera crocata

Bites by the woodlouse spider, Dysdera crocata, are virtually innocuous. The main symptom is minor pain, typically lasting less than 1h, probably due mostly to mechanical puncture of the skin. However, because the spider has a strong proclivity to bite, has large fangs which it bares when threatened and is commonly mistaken for the medically important brown recluse spider in the United States, documentation of the mild effects of its bites may prevent excessive, unwarranted and possibly harmful treatment. We present information on eight verified bites reported to us as well as eight additional bites recorded in the literature.

Arachnids submitted as suspected brown recluse spiders (Araneae: Sicariidae): Loxosceles spiders are virtually restricted to their known distributions but are perceived to exist throughout the United States

An Internet offer was made to identify any spider in the United States perceived to be a brown recluse spider, Loxosceles reclusa Gertsch & Mulaik (Sicariidae). In total, 1,773 arachnids from 49 states represented three orders (Araneae, Solifugae, and Opiliones) and the identifiable spiders (Araneae) consisted of 38 families, 88 genera, and 158 recognizable species. Participants from states at least half within the known brown recluse distribution submitted Loxosceles spiders 32- 89% of the time, except Louisiana and Mississippi with no submissions. From 25 of 29 states completely or almost completely outside of the range of Loxosceles spiders, no recluse spiders were submitted. Only two discoveries of brown recluses and two of the worldwide tramp species Loxosceles rufescens (Dufour) were submitted from nonendemic Loxosceles areas. States on distribution margins of brown recluse or other native Loxosceles spiders were intermediate in their Loxosceles submissions. This study showed that 1) the general public perceives brown recluses to occur over wide-ranging areas of the United States; and 2) brown recluses are frequently submitted from endemic states and almost never from nonendemic states, and therefore are virtually limited to their known distributions. This study corroborates opinions that diagnosis of brown recluse spider bites is best restricted to areas historically supporting proven, widespread populations of Loxosceles spiders.

Funnel-web spider bite: a systematic review of recorded clinical cases

OBJECTIVE

To investigate species-specific envenoming rates and spectrum of severity of funnel-web spider bites, and the efficacy and adverse effects of funnel-web spider antivenom.

DATA SOURCES

Cases were identified from a prospective study of spider bite presenting to four major hospitals and three state poisons information centres (1999-2003); museum records of spider specimens since 1926; NSW Poisons Information Centre database; MEDLINE and EMBASE search; clinical toxinology textbooks; the media; and the manufacturer's reports of antivenom use.

DATA EXTRACTION

Patient age and sex, geographical location, month, expert identification of the spider, clinical effects and management; envenoming was classified as severe, mild-moderate or minor/local effects.

DATA SYNTHESIS

198 potential funnel-web spider bites were identified: 138 were definite (spider expertly identified to species or genus), and 77 produced severe envenoming. All species-identified severe cases were attributed to one of six species restricted to NSW and southern Queensland. Rates of severe envenoming were: Hadronyche cerberea (75%), H. formidabilis (63%), Atrax robustus (17%), Hadronyche sp. 14 (17%), H. infensa (14%) and H. versuta (11%). Antivenom was used in 75 patients, including 22 children (median dose, 3 ampoules; range, 1-17), with a complete response in 97% of expertly identified cases. Three adverse reactions were reported, all in adults: two early allergic reactions (one mild and one with severe systemic effects requiring adrenaline), and one case of serum sickness.

CONCLUSIONS

Severe funnel-web spider envenoming is confined to NSW and southern Queensland; tree-dwelling funnel webs (H. cerberea and H. formidabilis) have the highest envenoming rates. Funnel-web spider antivenom appears effective and safe; severe allergic reactions are uncommon.

Brown recluse spider bites: a complex problem wound. A brief review and case study

Brown recluse spiders (Loxosceles reclusa) are responsible for virtually all documented cases of spider bites leading to significant necrosis. The actual spider bite often goes unnoticed for as long as 4 to 6 hours, which makes diagnosis and, therefore, appropriate treatment, difficult. The spider bite generally results in either a necrotic wound or systemic symptoms that can lead to hemolysis. The patient described in this article experienced both complications. Dapsone and hyperbaric oxygen therapy brought the adverse response to the bite under control. The patient was hospitalized for 7 days during treatment for hemolysis and an extensive, necrotic wound. Efforts are underway to develop an assay to provide a definitive diagnosis for the brown recluse spider bite, but none is yet commercially available. Antivenom is scarce; capture of the offending spider appears to be most helpful in the diagnosis and proper treatment of spider bites.

The epidemiology, syndromic diagnosis, management, and prevention of spider bites in the South

Unlike other arthropods, spiders rarely transmit communicable diseases, and thus play a critical role in the ecosystem by consuming other insects that frequently transmit human diseases, such as mosquitoes, ticks, and fleas. There are more than 30,000 species of spiders worldwide, most of which are venomous, but cannot inflict serious bites due to delicate mouthparts and short fangs. Other insect bites, skin infections, and chemical- or physical-agent exposures are often misdiagnosed as spider bites. Approximately 40 species from 4 major genera of spiders in Louisiana and throughout the South, however, can cause severe human envenomings, with dermonecrosis, systemic toxicity, and, rarely, death. Spider bites can usually be prevented by simple personal and domestic measures. Early species identification and specific management may help prevent serious sequelae of spider bites.

Morsures d’araignées : les aranéismes d’importance médicale

LIMITED RISKS: Although most species of spiders are venomous, only ten or so are able to induce human envenomations. From a systematic point of view, it is possible to distinguish the araneomorph spiders - or "true" spiders - from the mygalomorph spiders. Dangerous species for humans can be found in both groups. Regarding "true' spiders, two kinds of envenomation are frequent, ubiquitous and potentially severe: latrodectism (neurotoxic symptomatology) due to the Widow spiders of the Latrodectus species,and loxoscelism (viscero-cutaneous symptomatology). Regarding the mygalomorph spiders, the Australian species responsible for atraxism (neurotoxic symptomatology) are considered as the most dangerous. Most of the other mygalomorph spiders, when they bite, only provoke benign loco regional problems. A supplementary defensive weapon exists in certain South-American species: urticating hairs which may induce severe ocular damage.

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.

Loxoscelism: Old obstacles, new directions

Loxosceles spiders have a worldwide distribution and are considered one of the most medically important groups of spiders. Envenomation (loxoscelism) can result in dermonecrosis and, less commonly, a systemic illness that can be fatal. The mechanism of venom action is multifactorial and incompletely understood. The characteristic dermonecrotic lesion results from the direct effects of the venom on the cellular and basal membrane components, as well as the extracellular matrix. The initial interaction between the venom and tissues causes complement activation, migration of polymorphic neutrophils, liberation of proteolytic enzymes, cytokine and chemokine release, platelet aggregation, and blood flow alterations that result in edema and ischemia, with development of necrosis. There is no definitive treatment for loxoscelism. However, animal model studies suggest the potential value of specific antivenom to decrease lesion size and limit systemic illness even when such administration is delayed.

The global epidemiology, syndromic classification, management, and prevention of spider bites

Spiders are carnivorous arthropods that coexist with humans and ambush or ensnare prey. Unlike other arthropods, spiders rarely transmit communicable diseases, and play a critical role in the ecosystem by consuming other arthropods that frequently transmit human diseases, such as mosquitoes and flies. There are more than 30,000 species of spiders, most of which are venomous, but they cannot inflict serious bites due to delicate mouthparts and short fangs. The differential diagnosis of spider bites is extensive and includes other arthropod bites, skin infections, and exposure to chemical or physical agents. However, approximately 200 species from 20 genera of spiders worldwide can cause severe human envenomings, with dermonecrosis, systemic toxicity, and death. Spider bites can usually be prevented by simple personal and domestic measures. Early species identification and specific management may help prevent serious sequelae of spider bites.

Australian wolf spider bites (Lycosidae): clinical effects and influence of species on bite circumstances

BACKGROUND

Necrotic arachnidism continues to be attributed to wolf spider bites. This study investigates the clinical effects of bites by wolf spiders in Australia (family Lycosidae).

METHODS

Subjects were recruited prospectively from February 1999 to April 2001 from participating emergency departments or state poison information centers. Subjects were included if they had a definite bite by a wolf spider and had collected the spider, which was later identified by an arachnologist. Spiders were identified to the lowest taxonomic level possible and cephalothorax width was measured to correlate bite effects and spider size.

RESULTS

There were 45 definite wolf spider bites (23 male and 22 female patients; age range 1 to 69 years, median age 28 years). Species level identifications (14 species) were possible for 31 of 43 spiders belonging to seven different generic groupings. Most bites were by spiders from four generic groupings, Tasmanicosa (including 'Lycosa') (15), Venatrix (8), Venator (10), and Hogna (7). Bites occurred more commonly in south-eastern Australia and occurred throughout the year, with 7 bites (16%) in late autumn or winter. In 7 cases (16%) the person was swimming in or cleaning a pool. Seventy-two percent of bites occurred on distal parts of limbs. Pain occurred in all bites and was severe in 11 cases (24%), with a median duration of 10 min (IQR: 2-60 min). Other effects included puncture marks/bleeding (33%), swelling (20%), redness (67%), and itchiness (13%). Minor systemic effects occurred in three patients (7%): nausea (two), headache (one) and malaise (one). There were no cases of necrotic ulcers [0%; 97.5% CI 0-8%]. Tasmanicosa spider bites caused significantly more itchiness and redness, and large spiders (>5 mm) more often caused severe pain and left fang marks.

CONCLUSION

Wolf spider bites cause minor effects, no more severe than most other spiders, and do not appear to cause necrotic ulcers. The effects are likely to be due to mechanical injury, although minor local envenomation occurs with Tasmanicosa bites.

Reports of envenomation by brown recluse spiders (Araneae: Sicariidae) outnumber verifications of Loxosceles spiders in Florida

Bites attributed to the brown recluse spider, Loxosceles reclusa Gertsch & Mulaik, are frequently reported by medical personnel throughout Florida, whereas the extensive arachnological evidence contradicts the alleged widespread occurrence of Loxosceles spiders in the state. We compared reports of brown recluse spider bites made by medical personnel from a 6-yr Florida poison control center database to the known verifications of Loxosceles spiders from 100 yr of Florida arachnological data. Medical personnel diagnosed 124 brown recluse spider bites from 31 of Florida's 67 counties in 6 yr. In contrast, only 11 finds of approximately 70 Loxosceles spiders have been made in 10 Florida counties in 100 yr. Florida does not have sufficient widespread populations of Loxosceles spiders to warrant consideration of brown recluse spider envenomation as a probable etiology of dermonecrosis. Florida health care would improve if medical personnel would consider the multitude of other etiologies that manifest in dermonecrosis.

Prospective cohort study of definite spider bites in Australian children

OBJECTIVES

To describe the clinical effects of spider bites in a paediatric population and compare to bites in an adult population.

METHODS

Prospective follow up study of children with definite spider bites where the spiders were immediately collected and expertly identified. Cases were recruited from Australian emergency departments and poison information centres and followed up. Data were collected on circumstances of bites and clinical effects, and compared with similar data from adult spider bites.

RESULTS

There were 163 cases (62% male, 38% female; age <16, median age 7 years, interquartile range (IQR): 3-11 years). The median duration of effects was 2 h (IQR 0.25-12 h). The commonest spiders were Huntsman spiders (Sparassidae) and Orb weavers (Araneidae), and comparatively few bites by theridiid spiders, including Red-back spiders. Pain or discomfort occurred in all bites and was severe in 20%. Local effects included puncture marks/bleeding (36%) and red mark/redness (73%). Systemic effects occurred in only 6% of cases. There were no necrotic lesions or ulcers as a consequence of any spider bites (0%; 97.5% CI 0.0-2.2%) and no early allergic reactions or secondary infections. The median duration of clinical effects was shorter than adults, the frequency of severe pain was less than adults and systemic effects were less common in children.

CONCLUSIONS

Paediatric spider bite causes minor effects in the majority of cases, and is unlikely to cause necrotic ulcers, allergic reactions or infection. The severity and duration of effects differ from adults.

Clinical consequences of spider bites: recent advances in our understanding

Spider bite continues to be a controversial subject worldwide and attribution of clinical effects to different spiders is problematic because of poor case definition and paucity of clinical evidence. The effects of medically important spiders are sometimes underestimated and simultaneously there is misattribution of effects to harmless spider groups. The majority of suspected spider bites present as skin lesions or necrotic ulcers where the history of a spider bite must be confirmed. To be a definite spider bite, the patient must immediately observe the spider and there be evidence of the bite, such as pain. Important groups of spiders worldwide include the widow spiders (latrodectism), recluse spiders (loxoscelism) and some mygalomorph spiders including the Australian Funnel web spider. Most spiders only cause minor effects, including a large number of groups that have been implicated in necrotic arachnidism.

Epidemiological data, clinical admission gradation and biological quantification by ELISA of scorpion envenomations in Algeria: effect of immunotherapy

An epidemiological and biological survey of scorpion envenomation was conducted in Algeria. Analysis of 182 medical files showed that 70% of the patients were stung by Androctonus australis. Most accidents occurred during the morning (40%) or the evening (30%). Two-thirds of the patients reached a hospital 1 hour after being stung. Their clinical symptoms classified 78% of them as Grade I (mild envenomation) and 17% of them as Grade II (moderate envenomation) on admission to hospital. No severe envenomation (Grade III) was reported. Most patients were treated with antivenom by the intramuscular route. Blood samples were collected before and after antivenom immunotherapy. A good correlation was observed between the grade of envenomation on admission and the blood venom concentrations measured by ELISA. The venom concentration decreased as function of the interval between the sting and blood collection (t1/2 = 2 h). Intramuscular injection of 10 ml of antivenom did not efficiently neutralize scorpion venom. Inflammation was followed by measuring IL6 concentration. IL6 peaked 1 h after scorpion envenomation. This study shows that optimization of the administration of antivenom is required to achieve clinical efficiency. In particular, intravenous injection of a larger dose of a more potent antivenom should be considered.

Mouse spider bites (Missulena spp.) and their medical importance. A systematic review

OBJECTIVE

To determine the clinical significance of definite bites by mouse spiders (Actinopodidae: Missulena spp.) from published case reports/series and museum records.

DATA SOURCES

A computerised literature search of MEDLINE and EMBASE was undertaken. All cases reported to major Australian museums and reports from venom researchers working with mouse spiders were also reviewed. Textbooks on clinical toxinology were searched and further reports of cases were located.

STUDY SELECTION

All cases of definite spider bites where the spider was collected and identified by an expert as a mouse spider were included.

DATA EXTRACTION

All reports were evaluated and the following data extracted: patient demographics (age, sex, geographical location, season), bite site, local and systemic effects, and hospital attendance. Clinical effects were classified into three groups: severe neurotoxic envenoming, local neurotoxic effects or mild systemic effects, and minor local effects.

DATA SYNTHESIS

Forty definite bites were identified from around Australia, with only one case of severe envenoming (a 19-month-old child). Local neurotoxic effects occurred in six cases and minor systemic effects in five. There was no evidence of envenoming in most bite victims, and the rate of severe envenoming was 2.5% (95% CI, 0-13%). There were no recorded deaths.

CONCLUSIONS

In most cases, bites by mouse spiders cause only minor or moderate effects. Severe envenoming is rare and far less common than for funnel-web spider bites. Mouse spider bites do not appear to be a major medical problem.

Bites by Australian mygalomorph spiders (Araneae, Mygalomorphae), including funnel-web spiders (Atracinae) and mouse spiders (Actinopodidae: Missulena spp)

A number of mygalomorph spiders cause bites in Australia, including the funnel-web spiders (Hexathelidae, Atracinae: Hadronyche and Atrax) and mouse spiders (Actinopodidae: Missulena). There is ongoing debate about the significance of bites by mouse spiders and the frequency of severe envenoming by funnel-web spiders. We conducted a prospective cohort study of definite spider bites with expert spider identification and include the analysis of mygalomorph spiders here. Subjects were recruited prospectively from February 1999 to April 2003 from patients presenting to participating hospitals or contacting a state poison information centre. Forty-nine cases of bites by mygalomorph spiders were included: 16 were by funnel-web spiders, 13 by mouse spiders and 20 by other trapdoor spiders (Families Idiopidae and Nemesiidae). Of the 49 bites, 45 (92%) occurred on distal limbs (hands and feet). Local effects included severe pain (53%), puncture marks (61%) and bleeding (27%), local redness (33%). Itchiness did not occur. The following were highly statistically associated with mygalomorph spider bites compared to all other spiders (p<0.0001) circumstances (gardening at the time (likelihood ratio (LR) 7.9) and distal limb bites (LR 2.0)) and early clinical features (presence of puncture marks OR bleeding (2.3), or severe pain (2.0)). Of 16 funnel-web spider bites, there were 10 cases with minor local effects, four with moderate envenoming (non-specific systemic or local neurotoxicity) and two with severe envenoming requiring antivenom. In addition to local effects, mouse spider bites caused local paraesthesia in three cases, local diaphoresis in one case and non-specific systemic effects in five cases, but not severe envenoming. True trapdoor spider bites caused only minor effects. The data from a mixed species sample of funnel-web spiders confirms previous observations suggesting that only a small proportion of funnel-web bites cause severe effects. Mouse spider bites are unlikely to cause major envenoming but the clinical effects are consistent with neurotoxic venom and are more severe than the trapdoor spiders.