Brown Recluse Research Articles

Influence of Spider Silk on Refugia Preferences of the Recluse Spiders <I>Loxosceles reclusa</I> and <I>Loxosceles laeta</I> (Araneae: Sicariidae)

In a previous experimental study, recluse spiders Loxosceles reclusa Gertsch and Mulaik and Loxosceles laeta (Nicolet) (Araneae: Sicariidae) preferred small cardboard refugia covered with conspecific silk compared with never-occupied refugia. Herein, we investigated some factors that might be responsible for this preference using similar cardboard refugia. When the two Loxosceles species were given choices between refugia previously occupied by their own and by the congeneric species, neither showed a species-specific preference; however, each chose refugia coated with conspecific silk rather than those previously inhabited by a distantly related cribellate spider, Metaltella simoni (Keyserling). When L. laeta spiders were offered refugia that were freshly removed from silk donors compared with heated, aged refugia from the same silk donor, older refugia were preferred. Solvent extracts of L. laeta silk were chosen approximately as often as control refugia when a range of solvents (methylene chloride:methanol, water, and hexane) were used. However, when acetone was used on similar silk, there was a statistical preference for the control, indicating that there might be a mildly repellent aspect to acetone-washed silk. Considering the inability to show attraction to chemical aspects of fresh silk, it seems that physical attributes may be more important for selection and that there might be repellency to silk of a recently vacated spider. These findings are discussed in regard to pest management strategies to control recluse spiders.

Suspected Brown Recluse Envenomation: A Case Report and Review of Different Treatment Modalities

The Loxosceles reclusa, commonly known as the brown recluse spider, is responsible for virtually all cases of spider bites leading to a significant necrosis. We report the case of a 72-year-old man who presented to the Emergency Department complaining of back pain, weakness, and diarrhea. The patient stated that he sustained a bug bite 1 week before presenting to the hospital. His wound was necrotizing in nature and after an exhaustive work-up, the most likely etiology was found to be envenomation by a brown recluse spider, Loxosceles reclusa. This is an endemic cause of a necrotizing wound bite in areas of the Midwestern and Southern United States, but it is rarely reported in the Northeast.

Brown Recluse Spider ( Loxosceles reclusa) Envenomation Leading to Acute Hemolytic Anemia in Six Adolescents

Loxosceles reclusa (brown recluse spider) bites often cause local envenomation reactions; however, acute hemolysis from systemic loxoscelism is rare. To highlight this important diagnostic consideration for unexplained hemolysis in areas endemic for brown recluse spiders, we report on 6 adolescents with acute hemolytic anemia from presumed L reclusa bites.

Loxoscelism and Negative Pressure Wound Therapy (Vacuum-Assisted Closure): A Clinical Case Series

Brown recluse spider (Loxosceles sp) bites continue to be a significant challenge to manage clinically. Sequelae from these lesions range from chronic necrotic ulcers that persist for months to an acute life-threatening course of sepsis. Negative pressure wound therapy using vacuum-assisted closure (VAC) has been described for use in both acute and chronic wounds. We present a novel application for the use of this therapy in a retrospective review of eight clinical cases treated with the VAC.

Brown recluse spider (Loxosceles reclusa) envenomation in small animals.

To provide a comprehensive review of relevant literature regarding the brown recluse spider (BRS) and to define those criteria that must be satisfied before making a diagnosis of brown recluse envenomation. The complex venom of the BRS contains sphingomyelinase D, which is capable of producing all the clinical signs in the human and some animal models. There is no current commercially available test. In humans there are many proposed guidelines to achieve a definitive diagnosis; however, there are no established guidelines for veterinary patients. Currently, no consensus exists for treatment of BRS envenomation other than supportive care, which includes rest, thorough cleaning of the site, ice, compression, and elevation. Prognosis varies based on severity of clinical signs and response to supportive care.

Brown Recluse Spider Venom: Proteomic Analysis and Proposal of a Putative Mechanism of Action

Loxosceles intermedia spider venom was subjected to proteomic analysis through a MudPIT shot-gun approach to identify the protein composition. Were identified 39 proteins which seem to responsible by the lesion of different types of tissues, to some physiopathological actions and by the prevention of structural damage to the toxin structures.

Arachnids misidentified as brown recluse spiders by medical personnel and other authorities in North America

Misidentification of harmless or nearly benign arachnids as Loxosceles spiders by medical personnel and other authorities proliferates misinformation in regard to alleged loxoscelism and leads to decreased health care. This is especially true in areas of North America where Loxosceles spiders are rare or non-existent. A diverse assemblage of such misidentified arachnids is presented here. It is hoped that authorities will honestly assess their arachnological limitations and, instead, seek qualified arachnologists for spider identifications.

The Distribution of Brown Recluse Spiders in the Southeastern Quadrant of the United States in Relation to Loxoscelism Diagnoses

The southern and eastern margins of the range of the brown recluse spider run through the southeastern quadrant of the United States. Populations vary from abundant in states such as Arkansas and west and central Kentucky and Tennessee to absent in the Atlantic seaboard states. The diagnosis of loxoscelism should be restricted to areas of the southeastern United States where brown recluse spiders are both common and widespread. Better knowledge of the local presence of recluse spiders in one's area, along with the list of differential diagnoses for dermonecrosis, will allow medical personnel in the south to better assess the probability of spider involvement in a necrotic skin lesion. In North America, there are two groups of spiders proven to be medically important: the widow spiders (genus Latrodectus) and the recluse spiders (genus Loxosceles). The widow spiders are a known entity, because their distinctive coloration makes them readily identifiable by nonarachnologists. Also, the physiological mechanism of the venom, the antivenom to counter it, and the symptoms are known, causing misdiagnosis to rarely occur. In contrast, recluse spiders are almost at the other end of the spectrum. They are readily misidentified or confused with harmless spiders, and the physiological mechanism of the venom is still being elucidated. Furthermore, no antivenom is commercially available, and the brown recluse's infamy causes many skin lesions of nonarachnid origin to be misdiagnosed as brown recluse spider bites.

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.

The Mediterranean Recluse Spider, Loxosceles rufescens (Dufour): An Abundant but Cryptic Inhabitant of Deep Infrastructure in the Washington, D.C. Area (Arachnida: Araneae: Sicariidae)

Loxosceles rufescens (Dufour), a relatively cosmopolitan, synanthropic species commonly known as the Mediterranean recluse spider, inhabits numerous government buildings in the Washington, D.C. area. Like the closely related brown recluse spider ( L. reclusa Gertsch and Mulaik ) in the south-central United States, L. rufescens can be extremely abundant with in a structure. Unlike L. reclusa , D.C. populations of L. rufescens are essentially troglophilic, concentrated mainly in basements, foundation walls, and other man-made subterranean habitats, typically in close association with Periplaneta americana (L.) and/or Reticulitermes spp. It has not been observed either outdoors or in smaller, residential buildings. Since this spider is often misidentified as L. reclusa by entomologists who are unaware of L. rufescens ' widespread distribution and potential for persistent and dense local populations, we present photographs to aid in distinguishing the adults of these two similar species.

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.

S104 – Treatment of a Brown Recluse Spider Bite to the Face

Objectives 1) To raise awareness among otolaryngologists about the presentation, complications, and treatment options of brown recluse spider bites. 2) To present a case of a brown recluse spider bite to the face that was treated conservatively and had an excellent aesthetic result. Methods A 48-year-old woman was referred to the otolaryngology clinic with a dermonecrotic wound on the left upper lip from a brown recluse spider bite. The lesion consisted of a 4mm eschar with surrounding erythema, and the necrosis extended almost through the lip, sparing only the oral mucosa. She was given antibiotics and followed clinically. The eschar was left in place without debridement or topical treatments, and it fell off on day 40. Results After the eschar fell off on its own, the patient was left with complete healing of the necrotic area and a 1mm scar with mild erythema, giving her an excellent aesthetic result. Conclusions This case represents conservative management of a self-limited dermonecrotic lesion of the upper lip that resulted from a brown recluse spider bite. Conservative management should be considered with brown recluse spider bites, especially on the face, which has an excellent blood supply and where good aesthetic outcome is crucial.

Loxosceles Reclusa Bite to the Eyelid

The authors report a case of Loxosceles reclusa infestation on the eyelid. The specimen collected by swabbing the lesions with gauze was tested by using a venom-specific enzyme-linked immunosorbent assay. Loxosceles venom was detected in specimen. The patient was managed with conservative therapy that included saline compresses and ocular lubrication. The case presented with severe edema and necrosis on the left upper eyelid. On laboratory examination, a significant left shift of white blood cell count was detected. Although residual scar of the eyelid and punctate epitheliopathy on the inferior of cornea was detected, vision was not impaired. Supportive therapy may be reasonable treatment for Loxosceles reclusa infestation on the eyelids. The presence of venom proteins detected with an enzyme-linked immunosorbent assay technique is beneficial for supporting the diagnosis of Loxosceles envenomatio.

Are brown recluse spiders, Loxosceles reclusa (Araneae, Sicariidae) scavengers? The influence of predator satiation, prey size, and prey quality

Abstract I examined prey choice of the brown recluse spider (Loxosceles reclusa Gertsch & Mulaik 1940) with reference to unusual scavenging behavior originally reported by Sandidge (2003). Because scavenging is an unexpected behavior in normally predatory spiders, I hypothesized that special circumstances must converge for the brown recluse to prefer dead prey over live prey. I offered crickets (Acheta domesticus) to brown recluses in several choice experiments. I varied predator satiation (spiders not fed for two or four weeks), prey size (small or large), and prey quality (live, fresh dead, dead 1–2 days, 1 week or 1 month). Overall, recluses preferred live prey over dead, but their choice was influenced by all three variables. Recluses were more likely to scavenge when presented with large live prey paired with dead prey of equal size than when presented with small live and dead prey. Spiders that had fed recently were more likely to scavenge. Finally, recluses preferred dead prey that were freshly kil...

Cold temperature tolerance and distribution of the brown recluse spider Loxosceles reclusa (Araneae, Sicariidae) in Illinois

Abstract Although the temperatures at which the brown recluse spider (Loxosceles reclusa) is active have been described, no work has been done on lethal thermal limits that may influence the distribution of this medically important species. We tested the cold tolerance of L. reclusa at temperatures ranging from 3° C to −14° C. First, we tested spiders over brief 4-h exposures to a test temperature. Second, we tested spider tolerance to long-term, 30-da exposures to constant, low temperatures to simulate overwintering conditions. We also recorded temperatures beneath the plant litter layer and compared these to ambient surface air temperatures to estimate the effect of litter insulation. We then used the regression of ambient temperature to litter temperature to predict isotherms of litter retreats in Illinois during January, the month of lowest mean winter temperatures. Using the cold temperature lethal limits we found in the lab, we predicted a theoretical distribution of L. reclusa based solely on tempe...

Spiders of the genus Loxosceles (Araneae, Sicariidae): a review of biological, medical and psychological aspects regarding envenomations

Loxosceles spiders are of concern outside of the arachnological world because their bites can cause occasional necrotic skin lesions and/or systemic complications; these manifestations are known as loxoscelism. Once these spiders became well associated as medical entities, much notoriety was attained through the publication of medical case histories as well as tales of horrific wounds in the general literature. Although most Loxosceles spider bites are unremarkable, require only general supportive care, and often result in excellent outcome, they are an occasional source of severe dermonecrotic injury with long healing times and significant scarring. In rare cases of systemic loxoscelism, serious intravascular, nephrological and/or multi-organ damage can occur, sometimes resulting in death. However, also of concern is that loxoscelism is diagnosed by medical personnel or presumed by the general public in highly improbable scenarios preventing or delaying proper remedy, which can lead to deleterious outcome. Herein, Loxosceles spider biology and medical aspects are reviewed. In particular, an extensive discussion of the distribution of the brown recluse spider, L. reclusa Gertsch & Mulaik 1940, is presented along with life history characteristics, which relate to the medical aspects of the genus. Also presented are manifestations and epidemiology of loxoscelism, misdiagnoses of bites by the medical community, alternative diagnoses confused with recluse spider bites and a discussion of the psychological basis for the proliferation of the myth of loxoscelism by both the general public and the medical community. North and South American species are reviewed because this is where the genus predominates and is the region where the most pertinent research has originated.

Refugia Preferences by the SpidersLoxosceles reclusaandLoxosceles laeta(Araneae: Sicariidae)

A variety of refugia were offered to different instars of brown recluse spiders, Loxosceles reclusa Gertsch and Mulaik, and a South American recluse spider, L. laeta (Nicolet), to determine whether they preferred certain types of refugia spaces. Variables included (1) crevice widths ranging from 3.2 to 21 mm, (2) horizontal and vertical orientations, and (3) new refugia or refugia that had silk deposited by a previous conspecific resident. An additional 30-d assay with similar-sized refugia studied each species’ propensity for site fidelity or movement among refugia. L. reclusa preferred crevice widths ≥9 mm with no correlation of body size to crevice width, whereas L. laeta preferred crevice sizes ≥6.4 mm with a marginally significant correlation between crevice width and body size. Both species preferred (1) vertical instead of horizontal-oriented refugia and (2) refugia with conspecific silk compared with previously uninhabited refugia. There was no significant difference between the species in their propensity to move among refugia in the 30-d trial; however, both species had individuals that were always found in the same refugium for the entire assay and individuals changing refugia every 2–3 d. The propensity to switch refugia was not affected by the degree of starvation for the period tested as was initially hypothesized. The possible implications of this research toward developing novel control measures for Loxosceles spiders are discussed.

Refugia Preferences by the Spiders <I>Loxosceles reclusa</I> and <I>Loxosceles laeta</I> (Araneae: Sicariidae)

A variety of refugia were offered to different instars of brown recluse spiders, Loxosceles reclusa Gertsch and Mulaik, and a South American recluse spider, L. laeta (Nicolet), to determine whether they preferred certain types of refugia spaces. Variables included (1) crevice widths ranging from 3.2 to 21 mm, (2) horizontal and vertical orientations, and (3) new refugia or refugia that had silk deposited by a previous conspecific resident. An additional 30-d assay with similar-sized refugia studied each species' propensity for site fidelity or movement among refugia. L. reclusa preferred crevice widths > or = 9 mm with no correlation of body size to crevice width, whereas L. laeta preferred crevice sizes > or = 6.4 mm with a marginally significant correlation between crevice width and body size. Both species preferred (1) vertical instead of horizontal-oriented refugia and (2) refugia with conspecific silk compared with previously uninhabited refugia. There was no significant difference between the species in their propensity to move among refugia in the 30-d trial; however, both species had individuals that were always found in the same refugium for the entire assay and individuals changing refugia every 2-3 d. The propensity to switch refugia was not affected by the degree of starvation for the period tested as was initially hypothesized. The possible implications of this research toward developing novel control measures for Loxosceles spiders are discussed.

Images in Emergency Medicine

Images in Emergency Medicine

Reports of Envenomation by Brown Recluse Spiders Exceed Verified Specimens of Loxosceles Spiders in South Carolina

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. 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. 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. 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.