Brown Recluse Research Articles

Generalized vasculitic exanthem following Loxosceles reclusa envenomation

Brown recluse spider bites (BRSB) cause a myriad of reactions ranging from local necrosis to potentially lethal systemic involvement. Envenomation may induce a generalized exanthem known clinically but not described histologically. We report a 49-year-old female who developed a generalized exanthem 24 hours after BRSB. The histopathology demonstrated a necrotizing vasculitis similar to that seen at an envenomation site but without epidermal necrosis. Loxoscelism should be considered in patients residing in endemic areas who present with a vasculitic exanthem.

Community Associated Methicillin Resistant Staphylococcus Aureus Causing Fournier’s Gangrene and Genital Infections

We identified an emerging infectious disease of the genitoperineum caused by community associated, methicillin resistant Staphylococcus aureus. We report our experience with severe genital infections caused by community associated, methicillin resistant S. aureus occurring in 3 individuals who lacked any of the risk factors associated with traditional methicillin resistant S. aureus infection. Two cases were limited to scrotal abscesses that required only incision and drainage plus antimicrobial therapy. To our knowledge the third case represents the first and only reported case to date of Fournier's gangrene caused by community associated, methicillin resistant S. aureus. The prevalence of community associated, methicillin resistant S. aureus complicated skin and skin structure infections is increasing throughout the United States and other countries. Community associated, methicillin resistant S. aureus contains unique virulence factors but retains sensitivity to various nonbeta-lactam antibiotics. Historical risk factors associated with methicillin resistant S. aureus appear not to apply to infections associated with community associated, methicillin resistant S. aureus. Infections due to the latter cause have been identified in healthy individuals of all ages, races and ethnicities. Surgical and antimicrobial approaches to management are presented. Community associated, methicillin resistant S. aureus infections of the genitoperineum are likely to increase in incidence, necessitating heightened awareness on the part of the urologist.

Medical Applications of Digital Image Morphing

The authors present a unique medical technical application for illustrating the success and/or failure of the physiological healing process as a dynamically morphed video. Two examples used in this report include the healing of a severely fractured humerus from an explosion in Iraq and the other of dramatic tissue destruction from a poisonous spider bite. For the humerus, several sequential x-rays obtained throughout orthopedic surgical procedures and the healing process were morphed together representing a time-lapsed video of the healing process. The end result is a video that demonstrates the healing process in an animation that radiologists envision and report to other clinicians. For the brown recluse spider bite, a seemingly benign skin lesion transforms into a wide gaping necrotic wound with dramatic appearance within days. This novel technique is not presented for readily apparent clinical advantage, rather, it may have more immediate application in providing treatment options to referring providers and/or patients, as well as educational value of healing or disease progression over time. Image morphing is one of those innovations that is just starting to come into its own. Morphing is an image processing technology that transforms one image into another by generating a series of intermediate synthetic images. It is the same process that Hollywood uses to turn people into animals in movies, for example. The ability to perform morphing, once restricted to high-end graphics workstations, is now widely available for desktop computers. The authors describe how a series of radiographic images were morphed into a short movie clip using readily available software and an average laptop. The resultant video showed the healing process of an open comminuted humerus fracture that helped demonstrate how amazingly the human body heals in a case presentation in a time-lapse fashion.

Epidemiology of the brown recluse spider bite

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

Toxicity of two North American Loxosceles (brown recluse spiders) venoms and their neutralization by antivenoms

The toxic, biochemical, and immunological characteristics of L. boneti and L. reclusa venoms and its neutralization by anti–L. boneti and anti–L. reclusa antivenoms were studied. The electrophoretic profile showed very similar patterns and the toxic activities were very close. Immunological studies showed cross-reactivity among L. boneti and L. reclusa venoms, with L. boneti and L. reclusa experimental antivenoms, and anti-L. gaucho and anti-L. laeta antivenoms. The venom of L. laeta showed low immunological reactivity with the North American Loxosceles antivenoms. Experimental anti-North American Loxosceles antivenoms protected mice of the systemic toxicity and were able to prevent necrosis in rabbit skin after the injection of the venom. Both antivenoms displayed cross neutralization. The results showed that both Loxosceles venoms have very close toxic, biochemical, and immunological characteristics, and that either monospecific antivenoms or an antivenom raised with L. boneti and L. reclusa venoms as immunogens could be useful for treating bites by North American Loxosceles spiders.

Cutaneous and systemic effects of varying doses of brown recluse spider venom in a rabbit model.

To ascertain whether a dose response exists between the dose of brown recluse spider venom (BRSV) and the cutaneous and coagulation effects in a rabbit model. Cutaneous necrosis is a serious complication of brown recluse spider envenomation (spider bite with venom). Disseminated intravascular coagulation (DIC) is a dreaded complication of brown recluse envenomation in humans. New Zealand white (NZW) rabbits have proved to be a model for the study of therapeutic regimens to prevent skin necrosis after spider bites. We studied the venom's effects on the skin and the coagulation mechanism in this rabbit model to determine if a clear dose-response relationship could be established. Establishment of a dose-response relationship is an important first step in determining if the NZW rabbit is a suitable model to study both cutaneous and systemic effects of the venom. Thirty-six NZW rabbits were divided into three groups. One group received a saline injection, and the other two groups received a 4.0 microg or a 10.0 microg dose of purified BRSV intradermally into the skin on the dorsum of the back. Blood was collected at baseline, 24, 48, and 72 hours. Tissue specimens were obtained after seven days during the animal necropsy and gross and microscopic pathology examination was conducted to assess tissue damage. Measurements included complete blood count (CBC); platelets; PT; activated partial thromboplastin time (APTT); fibrinogen (clottable, immunological); coagulation factors II, V, VII, VIII, IX, X, XI, XII; anti-thrombin (AT); alpha-2 antiplasmin (AP); Protein C (PC); mixing studies; lupus anticoagulant screening; plasminogen; thrombin-antithrombin; fibrin degradation products (FDP); d-dimer; and thrombin time. Gross pathology results were consistent with previous studies that used higher doses of BRSV. The WBC and platelet counts decreased at 24 hours in the two groups receiving the BRSV (p < 0.05). BRSV produced a dose related prolongation in the APTT (p < 0.05). Levels of fibrinogen as well as factors V, VII, VIII, IX, X, AT, and AP (p < 0.05) were increased in response to the BRSV. Protein C decreased at 24 hours (p < 0.05) and remained low in other time points. Mixing studies corrected the prolonged APTTs to normal ranges. Factor IIXI and XII showed no significant alteration in response to the BRSV. In the model, both the size and depth of the eschar were dose-related. We also observed a dose related elevation in the APTT that corrected with mixing studies. The dose-response relationship suggests direct interference by a component of the venom, rather than an idiosyncratic response. We did not detect a deficiency of commonly measured coagulation factors or evidence of a lupus anticoagulant. Protein C demonstrated a decrease. Although DIC did not occur in this rabbit model, a dose-related elevation in APTT was noted. The finding that the elevation corrected with mixing studies suggests that a plasma factor is essential in the coagulopathy associated with brown recluse envenomation. Further studies to identify this factor could shed light on human coagulopathy following envenomation.

Spiderbite

In North America alone, there are more than 3,000 species of spiders. While most are harmless, several species including the Latrodectus (black widow), Atrax (funnel-web), and the Loxosceles (brown recluse) have been known to inflict varying degrees of injury to humans. While an overwhelming majority of spider bites may go unnoticed, others result in local skin reactions, necrotic cutaneous lesions, or a severe syndrome associated with hemolysis and death.

Diagnosis of loxoscelism in two Turkish patients confirmed with an enzyme-linked immunosorbent assay (ELISA) and non-invasive tissue sampling

Confirmed envenomations due to Loxosceles reclusa have not been previously documented in Turkey, to our knowledge. This brief report describes two Turkish patients with suspected envenomation by Loxosceles spider bites on the eyelids. Material obtained by swabbing the lesions with gauze was tested using a venom-specific enzyme-linked immunosorbent assay (ELISA). Both patients tested positive for the presence of Loxosceles venom.

Brown Spider Envenomation

The venom from spiders of the genus Loxosceles, the most famous being Loxosceles recluse (the most brown recluse spider) can cause serious poisoning. These spiders inhabit the south and south central states from Georgia through Texas and north to southern Wisconsin. They are commonly called violin spiders because of the violin-shaped marking on the dorsum of the cephalothorax. Many dermonecrotic lesions are incorrectly diagnosed as Brown recluse bites, as up to 50% of the diagnoses are in geographic regions of the country which do not have Loxosceles spiders. Sphingomyelinase D is the primary venom dermonecrotic factor. The toxin depletes serum hemolytic complement, prolongs the activated partial thromboplastin time and depletes clotting factors VIII, IX, XI, and XII. The venom induces rapid coagulation and occlusion of small capillaries, causing subsequent tissue necrosis. A classic "bulls eye" lesion develops, an erythematous area inside of which is a pale ischemic region that develops a dark necrotic center as the lesion matures. Healing is slow, and these ulcers may persist for months leaving a deep scar. Systemic signs occur less commonly but can be life threatening. The most prevalent sign is a hemolytic anemia with significant hemoglobinuria. There is no specific antidote. Dapsone a leukocyte inhibitor has been shown to be effective in treating dermal lesions in animal models. Conservative therapy includes several cleanings daily with Burrow's solution and hydrogen peroxide. Systemic signs of Loxosceles envenomation are potentially fatal and should be aggressively addressed. Hospitalization and intravenous fluid therapy may be needed to maintain adequate hydration and to protect renal function.

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

Necrotic arachnidism represents a common health problem and standard treatments are usually safe and effective. The aim of this study was to review documented Loxosceles species spider envenomations and identify the natural history of affected patients. 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. 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). 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.

Diagnosis of loxoscelism in a child confirmed with an enzyme-linked immunosorbent assay and noninvasive tissue sampling

Confirmation of mild bites caused by Loxosceles reclusa with swab testing has not been previously documented, to our knowledge. We report a case using an enzyme-linked immunosorbent assay (ELISA) test. A lesion lacking necrosis or other specific signs of loxoscelism was confirmed by identification of the Loxosceles venom and further confirmed by identification of a spider found in the patient's bed. This is a pilot single-case report for this enzyme-linked immunosorbent assay test. A sensitive and specific enzyme-linked immunosorbent assay designed to detect Loxosceles venom, using a specimen obtained by swabbing the lesion, can aid in diagnosis of loxoscelism.

OBSERVATIONS ON LOXOSCELES RECLUSA (ARANEAE, SICARIIDAE) FEEDING ON SHORT-HORNED GRASSHOPPERS

Abstract Observations on Loxosceles reclusa Gertsch & Mulaik 1940, feeding on various species of short-horned grasshoppers are presented. In this paper, prey attack strategy, duration of feeding, and behaviors surrounding feeding are reported. The spiders routinely fed on prey larger than themselves. Lightly touching prey with palps prior to feeding was always observed. The first quick bites and the first attachment sites were mostly peripheral, with later attachment sites central, on the head, thorax or abdomen. Feeding times, typically 3–10 hours, ranged up to 23 hours 38 minutes. The first long attachment was usually on a peripheral location of the prey (antenna or leg), but subsequent long attachments were more often central. Overall, 39.5% of long attachments were on the main body of the prey (not antenna or leg). Long attachments were then frequently followed by web spinning, or uncommonly, bradykinesia. Rocking, tugging or pulling at prey between attachments was common. The slow feeding from multip...

Immunizations, neonatal jaundice and animal-induced injuries

To review the literature published within the last year on three topics essential to clinical pediatrics: immunizations, neonatal jaundice, and animal-induced injuries. New vaccines that protect against meningococcus, pertussis and rotavirus are safe, effective and recommended for routine immunization. Young children remain a high priority for influenza vaccination while the world awaits further developments of avian influenza. Pneumococcal and varicella vaccinations have benefited many. Debate exists on how to screen for hyperbilirubinemia in neonates and new strategies are emerging to prevent it. There seems to be no link between hyperbilirubinemia and autism spectrum disorders. We have learned that rabies can be transmitted by transplantation; it remains a global public health problem and its incidence is frequently underestimated in developing nations. Lastly, brown recluse spider bites are often misdiagnosed. The face of pediatric infectious disease is changing as we incorporate new vaccines into our routine practice. Rotavirus vaccine has significant implications for the health of children across the globe. The management strategy for neonatal jaundice continues to focus on screening and prevention. We need to devote more energy to combating rabies in countries where it is endemic.

North and South American Loxosceles spiders: Development of a polyvalent antivenom with recombinant sphingomyelinases D as antigens

We report the cloning of sphingomyelinase D (SMD) cDNA from Loxosceles reclusa, Loxosceles boneti and Loxosceles laeta into bacterial expression systems, as well as optimization of expression conditions so as to obtain soluble and active recombinant enzymes. The recombinant mature SMDs, tagged with a histidine tail at the N- or C-termini, were compared in terms of toxicity and enzymatic activity, and were used as immunogens for the production of monovalent antisera in rabbits and F(ab′) 2 preparations in animals used for commercial antivenom production (horses). We performed studies on in vitro inhibition of enzymatic activity of natural venom preparations by antibodies generated against the tagged proteins. We also present and discuss the results of studies on the specific and para-specific in vivo protective potential of the rabbit and equine antibody preparations against the recombinant proteins themselves and natural venom preparations. Our conclusions support the feasibility of using recombinant SMDs for production and evaluation of polyvalent anti- Loxosceles antivenoms, and we offer data on the potential of paraspecific neutralization in the context of the antigenic groupings and the molecular phylogeny of those active SMDs for which amino acid sequence information is available.

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 1 h, 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.

Brown Recluse Spider Bites: A Case Report

The brown recluse spider is found more commonly in the Southeast and the Central Midwest. Its bite is not common because it is a shy spider that only bites if cornered. A severe bite may necrose a large area that requires skin grafting; systemic reactions rarely occur. This article discusses the brown recluse spider and presents a case study of a patient with two spider bites that did require extensive grafting.

Lateral gene transfer of a dermonecrotic toxin between spiders and bacteria

Spiders in the genus Loxosceles, including the notoriously toxic brown recluse, cause severe necrotic skin lesions owing to the presence of a venom enzyme called sphingomyelinase D (SMaseD). This enzyme activity is unknown elsewhere in the animal kingdom but is shared with strains of pathogenic Corynebacteria that cause various illnesses in farm animals. The presence of the same toxic activity only in distantly related organisms poses an interesting and medically important question in molecular evolution. We use superpositions of recently determined structures and sequence comparisons to infer that both bacterial and spider SMaseDs originated from a common, broadly conserved domain family, the glycerophosphoryl diester phosphodiesterases. We also identify a unique sequence/structure motif present in both SMaseDs but not in the ancestral family, supporting SMaseD origin through a single divergence event in either bacteria or spiders, followed by lateral gene transfer from one lineage to the other.

Brown Recluse Spider Bite to the Face

Oral and maxillofacial surgeons must be prepared to manage a variety of maxillofacial infections, both odontogenic and non-odontogenic in nature. While odontogenic infections are quite common, non-odontogenic infections can present with diagnostic and therapeutic challenges. An uncommon non-odontogenic infection is the cellulitis secondary to a spider bite. Few spider species have the ability to bite through human skin. Most of these insults result in only a small, red nodule centered within a larger, erythematous plaque. Symptoms are usually limited to pruritus and perhaps mild tenderness. The brown recluse and the black widow are 2 types of spiders that inhabit the United States that can cause serious injury or major medical problems to their victim. The bite of the brown recluse spider (Loxosceles reclusa) results in an envenomation that can have deleterious effects on the patient. Within 6 hours after the bite, pain and erythema develop at the site. The area of erythema spreads during the first 24 hours and may turn bluish-purple. Necrosis of the skin often occurs 24 to 48 hours later. Signs include bullae formation, cyanosis, and hyperesthesia. Depending on their size, complete resolution of these lesions can take from weeks to months. Systemic symptoms include fever, chills, malaise, vomiting, and arthralgias. Less common but more severe reactions to the venom have resulted in hemolytic anemia, convulsions, renal failure, shock, disseminated intravascular coagulation, and rarely, death. Brown recluse spider bites usually occur on the extremities or the trunk, but bites to the face have been reported. Treatment of a brown recluse spider bite is controversial and ranges from conservative comfort measures including rest, ice compresses, and elevation, to drug therapy and surgical excision.

Brown recluse spider (Loxosceles reclusa) venom phospholipase D (PLD) generates lysophosphatidic acid (LPA)

Envenomation by the brown recluse spider (Loxosceles reclusa) may cause local dermonecrosis and, rarely, coagulopathies, kidney failure and death. A venom phospholipase, SMaseD (sphingomyelinase D), is responsible for the pathological manifestations of envenomation. Recently, the recombinant SMaseD from Loxosceles laeta was demonstrated to hydrolyse LPC (lysophosphatidylcholine) to produce LPA (lysophosphatidic acid) and choline. Therefore activation of LPA signalling pathways may be involved in some manifestations of Loxosceles envenomation. To begin investigating this idea, we cloned a full-length cDNA encoding L. reclusa SMaseD. The 305 amino acid sequence of the L. reclusa enzyme is 87, 85 and 60% identical with those of L. arizonica, L. intermedia and L. laeta respectively. The recombinant enzyme expressed in bacteria had broad substrate specificity. The lysophospholipids LPC, LPI (18:1-1-oleyol lysophosphatidylinositol), LPS, LPG (18:1-1-oleoyl-lysophosphatidylglycerol), LBPA (18:1-1-oleoyl-lysobisphosphatidic acid) (all with various acyl chains), lyso-platelet-activating factor (C16:0), cyclic phosphatidic acid and sphingomyelin were hydrolysed, whereas sphingosylphosphorylcholine, PC (phosphatidylcholine; C22:6, C20:4 and C6:0), oxidized PCs and PAF (platelet-activating factor; C16:0) were not hydrolysed. The PAF analogue, edelfosine, inhibited enzyme activity. Recombinant enzyme plus LPC (C18:1) induced the migration of A2058 melanoma cells, and this activity was blocked by the LPA receptor antagonist, VPC32183. The recombinant spider enzyme was haemolytic, but this activity was absent from catalytically inactive H37N (His37-->Asn) and H73N mutants. Our results demonstrate that Loxosceles phospholipase D hydrolyses a wider range of lysophospholipids than previously supposed, and thus the term 'SMaseD' is too limited in describing this enzyme.

Brown recluse spiders: A review of biology, life history and pest management

Members of the spider genus Loxosceles (Araneae: Sicariidae) are found throughout the world. Their venom can cause severe open necrotic lesions in humans that can take several months to heal. Bite victims may also develop systemic reactions that can be life-threatening if medical attention is delayed or unavailable. Many Loxosceles species establish large populations in human habitats, creating a threat to human health and safety. Loxosceles reclusa, the brown recluse spider, is by far the most abundant spider species in many homes throughout the south-central United States. There has been an increase in awareness of brown recluse spiders, primarily due to negative media coverage of disfiguring bites and immense, slow-healing wounds. Although the bite of L. reclusa has been identified as a cause of necrotic lesions for nearly five decades, surprisingly few studies examine the biology of these spiders, and none have examined their association with humans. Few data have been published on the killing efficacy of pesticides on L. reclusa. Although millions of dollars are spent each year to control populations of L. reclusa in homes, no studies have been conducted to test newly developed chemicals or examine the benefits of integrated pest management practices. Here, we review historical accounts of pest management for L. reclusa populations and previous laboratory studies of biology and behavior. We then discuss how current studies of urban ecology, biological control, and urban pest management contribute to the management of L. reclusa populations in human habitats.