Brown Recluse Research Articles

The influence of spider news on online information-seeking.

Fear of spiders is a widespread condition often disproportionate to the actual danger spiders pose to humans. Likely rooted in evolutionary history, fear of spiders might also have a cultural component. Recent studies have shown that a significant fraction of spider-related media reports are misleading and sensationalistic. Information-seeking behaviours serve as common coping mechanisms for our fears and anxieties, yet the link between spider-related news stories and such behaviors remains unexplored.We hypothesize that media reports foster concern about spiders, resulting in an increased awareness of spiders and health issues associated with them. We extracted 1486 reports in English from a public database providing a content-analysis of spider-related online traditional media reports published between 2010-2020. We examined whether the volume of spider-related queries in Google Trends, Wikipedia, and iNaturalist increased in the week following the publication of each news story.Sensationalistic news stories were associated with a small, significant increase in search volumes, compared to non-sensationalistic ones. The search volume for "brown recluse" (Loxosceles reclusa), which are potentially dangerous spiders, was higher after the publication date of news related to human-spider encounters. There was a significant positive relationship between the number of spider-related news stories published in a given month and the traffic on target spider-related Wikipedia pages, especially so for the page on brown recluse spiders.Our results suggest that traditional media have a detectable impact on the behaviour of the general public towards spiders, supporting the hypothesis that the fear of spiders is perpetuated by culture. Additionally, our findings indicate that information-seeking behaviour is a common response to learn about spiders and potentially fact-check spurious claims found in sensationalised news. By recognizing the role of media in shaping attitudes towards spiders and acknowledging the benefits of accurate representation, we can lay the foundation for a more informed and harmonious relationship between humans and spiders.

ID: 329655 Stellate Ganglion Blocks to Treat CRPS and Neuropathy Caused by Brown Recluse Spider Bite

ID: 329655 Stellate Ganglion Blocks to Treat CRPS and Neuropathy Caused by Brown Recluse Spider Bite

Binding of green tea epigallocatechin gallate to the arginine kinase active site from the brown recluse spider (Loxosceles laeta): A potential synergist to chemical pesticides

Loxosceles spp. spiders can cause serious public health issues. Chemical control is commonly used, leading to health and environmental problems. Identifying molecular targets and using them with natural compounds can help develop safer and eco-friendlier biopesticides. We studied the kinetics and predicted structural characteristics of arginine kinase (EC 2.7.3.3) from Loxosceles laeta (LlAK), a key enzyme in the energy metabolism of these organisms. Additionally, we explored (−)-epigallocatechin gallate (EGCG), a green tea flavonoid, as a potential lead compound for the LlAK active site through fluorescence and in silico analysis, such as molecular docking and molecular dynamics (MD) simulation and MM/PBSA analyses. The results indicate that LlAK is a highly efficient enzyme (KmArg 0.14 mM, KmATP 0.98 mM, kcat 93 s−1, kcat/KmArg 630 s−1 mM−1, kcat/KmATP 94 s−1 mM−1), which correlates with its structure similarity to others AKs (such as Litopenaeus vannamei, Polybetes pythagoricus, and Rhipicephalus sanguineus) and might be related to its important function in the spider's energetic metabolism. Furthermore, the MD and MM/PBSA analysis suggests that EGCG interacted with LlAK, specifically at ATP/ADP binding site (RMSD <1 nm) and its interaction is energetically favored for its binding stability (−40 to −15 kcal/mol). Moreover, these results are supported by fluorescence quenching analysis (Kd 58.3 μM and Ka 1.71 × 104 M-1). In this context, LlAK is a promising target for the chemical control of L. laeta, and EGCG could be used in combination with conventional pesticides to manage the population of Loxosceles species in urban areas.

Correction to "A Brief Overview of the Toxic Sphingomyelinase Ds of Brown Recluse Spider Venom and Other Organisms and Simple Methods To Detect Production of Its Signature Cyclic Ceramide Phosphate".

Correction to "A Brief Overview of the Toxic Sphingomyelinase Ds of Brown Recluse Spider Venom and Other Organisms and Simple Methods To Detect Production of Its Signature Cyclic Ceramide Phosphate".

The use of therapeutic plasma exchange in systemic loxoscelism induced treatment resistant hemolytic anemia: A case report

Brown recluse spider bites can lead to severe reactions such as skin necrosis,hemolytic anemia, and multiorgan failure, which can be life-threatening. Therapeutic plasma exchange has been reported to provide clinical benefit for such cases. In thisreport, we present a case of a brown recluse spider bite that was successfully treated with therapeutic plasma exchange and compare it with previous case reports.

Discovery of broadly-neutralizing antibodies against brown recluse spider and Gadim scorpion sphingomyelinases using consensus toxins as antigens.

Broadly-neutralizing monoclonal antibodies are becoming increasingly important tools for treating infectious diseases and animal envenomings. However, designing and developing broadly-neutralizing antibodies can be cumbersome using traditional low-throughput iterative protein engineering methods. Here, we present a new high-throughput approach for the standardized discovery of broadly-neutralizing monoclonal antibodies relying on phage display technology and consensus antigens representing average sequences of related proteins. We showcase the utility of this approach by applying it to toxic sphingomyelinases from the venoms of species from very distant orders of the animal kingdom, the recluse spider and Gadim scorpion. First, we designed a consensus sphingomyelinase and performed three rounds of phage display selection, followed by DELFIA-based screening and ranking, and benchmarked this to a similar campaign involving cross-panning against recombinant versions of the native toxins. Second, we identified two scFvs that not only bind the consensus toxins, but which can also neutralize sphingomyelinase activity of native whole venom in vitro. Finally, we conclude that the phage display campaign involving the use of the consensus toxin was more successful in yielding cross-neutralizing scFvs than the phage display campaign involving cross-panning.

A Brief Overview of the Toxic Sphingomyelinase Ds of Brown Recluse Spider Venom and Other Organisms and Simple Methods To Detect Production of Its Signature Cyclic Ceramide Phosphate.

A special category of phospholipase D (PLD) in the venom of the brown recluse spider (Loxosceles reclusa) and several other sicariid spiders accounts for the dermonecrosis and many of the other clinical symptoms of envenomation. Related proteins are produced by other organisms, including fungi and bacteria. These PLDs are often referred to as sphingomyelinase Ds (SMase Ds) because they cleave sphingomyelin (SM) to choline and "ceramide phosphate." The lipid product has actually been found to be a novel sphingolipid: ceramide 1,3-cyclic phosphate (Cer1,3P). Since there are no effective treatments for the injury induced by the bites of these spiders, SMase D/PLDs are attractive targets for therapeutic intervention, and some of their features will be described in this minireview. In addition, two simple methods are described for detecting the characteristic SMase D activity using a fluorescent SM analog, (N-[12-[(7-nitro-2-1,3-benzoxadiazol-4-yl)amino]dodecanoyl]-SM (C12-NBD-SM), that is cleaved to C12-NBD-Cer1,3P, which is easily separated from other potential metabolites by thin-layer chromatography and visualized under UV light. Besides confirming that C12-NBD-Cer1,3P is the only product detected upon incubation of C12-NBD-SM with brown recluse spider venom, the method was also able to detect for the first time very low levels of activity in venom from another spider, Kukulcania hibernalis The simplicity of the methods makes it relatively easy to determine this signature activity of SMase D/PLD. SIGNIFICANCE STATEMENT: The sphingomyelinase D/phospholipase D that are present in the venom of the brown recluse spider and other sources cause considerable human injury, but detection of the novel sphingolipid product, ceramide 1,3-cyclic phosphate, is not easy by previously published methods. This minireview describes simple methods for detection of this activity that will be useful for studies of its occurrence in spider venoms and other biological samples, perhaps including lesions from suspected spider bites and infections.

A Nocardia brasiliensis Infection Secondary to a Loxosceles reclusa Bite: A Spinal Cord Stimulation Case Report

Background: Nocardia brasiliensis, an uncommon human pathogen, is rarely seen in infections secondary to insect bites or stings. However, Nocardia brasiliensis can infect an individual through an ulcerative wound, such as one mediated by the phospholipase D toxin immune response following a Loxosceles reclusa (i.e., brown recluse spider) bite. Case Report: This report presents the case of a patient who underwent a spinal cord stimulator (SCS) trial with an unknown brown recluse spider bite on her left foot. We describe the Nocardia brasiliensis cutaneous infection following a brown recluse bite and the effective management of the infection through long-term antibiotic use, which allowed for the eventual successful implantation of the SCS. Conclusion: The present case urges health care providers to conduct thorough, full-body examinations prior to any surgical procedure to identify and treat all remote infections prior to SCS implantations, as advised by the Neurostimulation Appropriateness Consensus Committee’s recommendations for infection prevention. Key words: Nocardiosis, Loxosceles reclusa, Nocardia brasiliensis, spinal cord stimulation, case report

Cutaneous Blastomycosis Presenting as a Nonhealing Wound in the Northeast United States: A Case Report.

Primary cutaneous blastomycosis is a rare presentation of infection caused by direct inoculation of a wound. We present a 61-year-old male with an extensive history of wound dehiscence and wound care noncompliance after a bite from a brown recluse spider on the left thigh while on vacation in Cape Cod in September of 2020. After antibiotic therapy and culture, treatment involved debridement, split thickness skin grafting, strict wound vacuum-assisted closure care, and oral itraconazole. This brief demonstrates a case of blastomycosis arising from trauma in a non-endemic region for infection and serves as an example of successful management of the longstanding wound.

Brown Recluse Spider Bite: A Case Report of Severe Hemolysis and Sepsis

Abstract Introduction/Objective The brown recluse spider, Loxosceles reclusa, is commonly found in the southern and central United States and is known for its venomous bite. It has six eyes, uniformly colored abdomen and legs, is around 1 cm in length and prefers to live in warm, dark and dry places. Its bite in humans can cause skin necrosis as well as more severe manifestations including acute hemolytic anemia, disseminated intravascular coagulation (DIC), rhabdomyolysis and renal failure. Methods/Case Report We present a case report of a 27 year old male with no known past medical history who was referred from another medical center with a critical hemoglobin of 3.6 g/dl and acute hemolytic anemia that was not responsive to packed red blood cell transfusion and intravenous immunoglobulin treatment. He reported of having bitten by a brown recluse spider 8 days ago on the right scapular region. He started developing wound and pain in the area 2 days later when he was admitted to the hospital for a day and treated with antibiotics. His white blood cell count (WBC) at the time was mildly elevated with near normal hemoglobin and was incidentally found to have COVID 19 positivity. After being discharged, he developed fever with chills, dark urine, body ache, headache, nausea and vomiting. When presented to our hospital, laboratory review exhibited normocytic normochromic anemia with elevated bilirubin and decreased haptoglobin showing a hemolytic picture. The patient also displayed severe leukocytosis (WBC count: 53.50) with absolute neutrophilia, lymphocytosis, and monocytosis. Monocyte distribution width (MDW) was 30.02. These changes were attributed to be reactive to venom effect and sepsis. The patient showed significant improvement with plasmapheresis. Results (if a Case Study enter NA) NA. Conclusion The diagnosis of systemic loxoscelism is often difficult and delayed. Brown recluse spider bites may not always present with sharp stings to be noticed and reported by the patient. Presence of another infectious condition, like COVID 19 in this case, may divert the diagnosis. An elaborate patient history, physical examination for bite wound and patient education may help in identifying the cause early. Spider bites should be considered as a differential diagnosis in a patient with dermonecrosis and abrupt onset hemolysis or sepsis. Prompt treatment can prevent development of DIC, renal failure and life threatening conditions.

Venomous spiders of Albania -does an increase of temperature influence the toxicity of spider venom?

Black widow spiders (Latrodectus sp.) are distributed worldwide, and in Albania the L. tredecimguttatus Rossi, 1790 has been the dominant spider. Other medically important spiders in Albania include the brown recluse with symptoms known as loxoscelism, the false black widow and the egg sac spiders; the last two inducing similar symptoms to a wasp sting. Methods: The data analyzed is from a decade-long study of 125 patients hospitalized in the regional hospital of Fier County, in the Western Lowland of Albania from May 2009 and to October 2018. Objective: Although the venom is rarely fatal, the recent spider bites raise questions about the influence of higher air temperatures on their possibly increased toxicity. Results: Significantly the severity of the α-latrotoxin rises during the summer, when human–spider contact frequency is higher and when the black widow spiders have an increased motivation to protect their egg sacs. Conclusion: This study revealed an increased severity of the black widow bites with respect to patient health, shown via all the severe systemic symptoms, during those months with higher temperatures.

Systemic loxoscelism induced warm autoimmune hemolytic anemia: clinical series and review

ABSTRACT Objectives Describe the development of warm autoimmune hemolytic anemia warm (AIHA) secondary to a brown recluse spider (Loxosceles reclusa) bite is known as systemic loxoscelism; and review epidemiology, clinical manifestations, diagnostic work-up, pathophysiology, and treatment options associated with warm AIHA secondary to systemic loxoscelism. Methods Cases series of two cases of warm AIHA due to systemic loxoscelism and a review of the current literature: epidemiology, clinical manifestations, diagnostic work-up, pathophysiology, and treatment options associated with warm AIHA secondary to systemic loxoscelism. Results Presented here are two cases of warm AIHA due to systemic loxoscelism. Each patient was generally healthy appearing and presented with symptomatic anemia in the setting of brown recluse spider bites. Both patients were eventually found to have warm AIHA. Upon recognition of the diagnosis, the patients were started on corticosteroids and aggressive intravenous fluid hydration. In addition, they received transfusions of packed red blood cells. Their clinical courses improved, and they recovered to eventually be discharged home. Conclusion Envenomation by a brown recluse spider, Loxosceles reclusa, can result in systemic loxoscelism which can cause warm AIHA. The diagnosis of warm AIHA is confirmed by the direct antiglobulin/Coomb's test. Warm AIHA can be a life-threatening disease process. Hemodynamic support with intravenous fluids and RBC transfusion is the initial step in the management of these patients. Corticosteroids are the mainstay of current management. Second line treatments include rituximab. Rarely patients require splenectomy for refractory disease. Corticosteroids should be tapered over a three-month period.

Observations of dispersal in the brown recluse spider, Loxosceles reclusa (Araneae: Sicariidae)

We studied dispersal of brown recluse spiders, Loxosceles reclusa (Gertsch & Mulaik, 1940), around an infested urban garage using pitfall traps. Over a four-month period, 23 were captured from a source population that averaged 100 individuals observed in nocturnal censuses. Loxosceles reclusa were captured in far lower proportions compared to their potential source population size than were other spiders such as theridiids and agelenids that also resided in the garage, albeit in far lower numbers. Dispersal was weakly positively correlated with the source population size. We compare our findings to anecdotal reports from prior studies and the general consensus that brown recluse spiders are poor dispersers to argue for more detailed examination of the movement and specific habitat requirements of this medically important spider. Habitat specificity and high mortality during dispersal may help explain the highly clustered spatial distribution of brown recluse spiders, not only a lack of attempted emigration.

Verified envenomations by crevice weaver spiders (genus Kukulcania): Bites are of minor expression but the spiders are commonly misidentified as medically important brown recluses (genus Loxosceles) in North America

From southern North America, five verified bites by crevice weaver spiders, Kukulcania spp. (Filistatidae), are presented here, three of which are pediatric cases. Although the envenomation manifestations were of minimal expression, the salient aspect of this report is that Kukulcania spiders are frequently misidentified as brown recluse spiders (genus Loxosceles) which are infamous for causing serious dermonecrosis and rarely, life-threatening systemic effects. Misidentification of this relatively harmless spider as a medically important recluse when presented to a physician in an envenomation episode could lead to unwarranted and overzealous treatment such as contraindicated debridement of the affected area.

Delayed Endothelial Immune Ring after Brown Recluse Spider Bite

Left brow eschar after 8 days (inset). Initial treatment was a tetanus shot and doxycycline for 1 week. Four weeks after the incident, the patient developed redness, discomfort, and blurred vision in his left eye presenting with central corneal swelling and an endothelial immune ring, without evidence of spider hair(s). Tobramycin/dexamethasone drops were used 3 times per day and tapered over 2 months with improvement after 1 week and complete resolution thereafter. We hypothesize that the (spider) antigen was introduced into the pericentral stroma via a fine spider hair (Magnified version of Figure is available online at www.aaojournal.org).

Laboratory Predictors of Hemolytic Anemia in Patients With Systemic Loxoscelism.

To develop a sensitive and specific protocol for detecting preclinical hemolysis in patients with brown recluse spider (BRS) bites by comparing a large cohort of individuals with brown recluse spider (BRS) bites with and without hemolytic anemia. A cross-sectional, retrospective analysis of clinical features and laboratory values, including urinalysis (UA) and peripheral blood results, and timing of positive laboratory values prior to a significant drop in hematocrit was performed to evaluate effective predictors of clinically significant hemolysis. In total, 275 patients with BRS bites were identified (64 with hemolytic anemia). Sensitivity and specificity of UA positive for blood (with and without microscopic hematuria) for detecting hemolysis were 72% and 75%, respectively. The combination of elevated serum total bilirubin (TB) and lactate dehydrogenase (LDH) had greater sensitivity (94%) and specificity (91%) for detecting patients developing hemolysis. When TB and LDH were evaluated prior to a significant decrease in hematocrit, they were positive in 82% of cases, while UA was positive for blood prior to a hematocrit decrease in 38% of cases. Serum TB and LDH levels are more effective at detecting preclinical hemolysis than UA and should be serially analyzed to triage patients with BRS bites before life-threatening hemolysis occurs.

Identification and quantification of 11 airborne biochemicals emitted by the brown recluse and another primitive hunting spider using headspace solid-phase microextraction-GC/MS.

Loxosceles reclusa, or brown recluse spider, is a harmful household spider whose habitat extends throughout the Midwest in the USA and other regions in the world. The pheromones and other biomolecules that facilitate signaling for brown recluses and other spider species are poorly understood. A rapid and sensitive method is needed to analyze airborne spider signaling biomolecules to better understand the structure and function of these biochemicals in order to control the population of the spiders. In this study, we developed a novel headspace solid-phase microextraction (HS-SPME)-GC/MS method to analyze potential pheromones and biomolecules emitted by the brown recluse spider. The method is highly selective and sensitive for biomolecule identification and quantification from a single live spider. Using this novel non-destructive HS-SPME-GC/MS technique, we identified 11 airborne biomolecules, including 4-methylquinazoline, dimethyl sulfone, 2-methylpropanoic acid, butanoic acid, hexanal, 3-methylbutanoic acid, 2-methylbutanoic acid, 2,4-dimethylbenzaldehyde, 2-phenoxyethanol, and citral (contains both isomers of neral and geranial). Some of these airborne biomolecules were also reported as semiochemicals associated with biological functions of other spiders and insects. The method was also applied to study the airborne biochemicals of Plectreurys tristis, another primitive hunting spider with a poor web, enabling quantitation of the same compounds and demonstrating a difference in signaling molecule concentrations between the two species. This method has potential application in the study of pheromones and biological signaling in other species, which allows for the possibility of utilizing attractant or deterrent functions to limit household populations of harmful species.

Effects of food, kinship, and density on the longevity of spiderlings

Cannibalism is a behavioral characteristic found in a wide variety of animal groups. Although the rates of cannibalism can vary from one group to another, studies indicate that the main factors contributing to an increase in the frequency of such behavior are the availability of food, population density, the behavior and availability of victims, and environmental stress. We carried out different laboratory experiments to assess whether different factors such as the presence or absence of food among siblings and non-siblings, and at different densities among conspecific and heterospecific individuals, affect longevity of recently emerged Brazilian brown recluse (Loxosceles intermedia Mello-Leitão, 1934) and Chilean recluse (Loxosceles laeta (Nicolet, 1849)) spiderlings during periods of starvation. The results revealed that the survivorship of L. laeta during starvation was significantly higher than that of L. intermedia and that the addition of conspecific individuals increased survival rates by 1.5- and 1.6-fold, respectively. The tolerance of conspecifics differed between the two species, and generally, cannibalism was not observed, probably due to the risk of predation and limited consumption by weakened spiders, which coincided with the continued availability of endogenous vitelline reserves, thus indicating that the use of these spiderlings as a food resource may act to regulate starvation in more resistant spiders. The greater longevity and conspecific tolerance of L. laeta may be important factors contributing to the establishment of large populations of this spider in restricted areas, whereas for L. intermedia, hunger probably functions as a trigger for dispersal.

Ecological niche divergence between the brown recluse spiders Loxosceles laeta and L. surca (Sicariidae) in Chile

ABSTRACT The laeta species group is the main source of Loxosceles species in Chile, a genus of medical importance due to the cytotoxic properties of its venom and the synanthropic habits of its dominant species, Loxosceles laeta. However, a poorly studied, cryptic, and putative sister species, Loxosceles surca, is also known to live in Chile at latitudes that overlap with L. laeta. In contrast to L. laeta, L. surca lives in natural areas away from humans. We used DNA sequences from L. surca to infer the phylogenetic history of this species and its congenerics. Additionally, we used ecological niche modelling to define the ecology of this species in contrast to its sister species. Our results show that L. surca does, indeed, belong to the laeta species group, and is likely a sister species to L. laeta. Although these species are fairly cryptic with respect to each other, the substantial genetic divergence between them is consistent with other distinct sister species in this genus. The laeta group is also sister to the large reclusa group that radiated into the Caribbean, Central, and North America. The phylogeny further supports the contention that L. diaguita belongs in its own species group separate from laeta. Our ecological niche analysis shows that L. surca and L. laeta have distinctly different allopatric habitats, and we suggest that these differences explain why one species became synanthropic, while the other did not.

Nodules on the Thigh after Brown Recluse Spider Venom Bite: A Quiz.

Nodules on the Thigh after Brown Recluse Spider Venom Bite: A Quiz.