A recent clinical case involving a Poecilotheria regalis bite was treated with Mexican L. mactans antivenom (Aracmyn Plus, Silanes, Mexico), resulting in the improvement of some of the symptoms. This could be attributed to cross-reactivity caused by structural similarities between certain components of L. mactans and P. regalis venoms. The aim of the present study was to evaluate the cross-reactivity of P. regalis venom with commercial antivenoms that target the venom of the Latrodectus mactans spider and American scorpions. Hyaluronidase activity was evaluated via a turbidimetric method, while edema was evaluated in rat paw via a histopathological analysis. Cross-reactivity was determined using SDS-PAGE and western blotting. The results obtained showed that both antivenoms significantly reduced the hyaluronidase activity of P. regalis venom and that induced by other tarantula venoms. Aracmyn Plus did not reduce inflammation caused by P. regalis venom. Furthermore, it was previously observed that this antivenom failed to reduce the characteristic muscle cramps induced by this venom. Finally, western blotting revealed that both antivenoms showed cross-reactivity with P. regalis venom. The above findings suggest that hyaluronidases and other high-molecular-weight components exhibit structural similarities across the venoms from different arachnid species.

Latrodectus, or "black widow" spiders, are found worldwide. Black widow envenomations are rare occurrences in Greece. Black widow bites cause unremarkable local lesions that may also include systemic signs and symptoms. Our purpose is to present a rare case of a black widow spider bite.  Herein, we report the case of a 66-year-old farmer who presented to our hospital due to abdominal pain and was admitted after he was bitten by a black widow spider. Our patient showed the typical symptoms of latrodectism, that is, rubor and pain at the bite spot, washboard abdomen, rhabdomyolysis, and lower-extremities neuromuscular paralysis. Our case was complicated by acute renal failure, which is not common in such cases. A quite remarkable finding is the detection and capture of the culprit arthropod from the patient's clothes and its identification by expert military veterinarian-arachnologists. The patient was completely cured and discharged after a week-long hospitalization. Black widow spider bites, rare as they may be, especially in Greece, should be considered within the differential diagnosis of unremarkable local lesions, rhabdomyolysis, or acute renal failure.

IntroductionThe black widow spider, Latrodectus mactans, stands out as one of the most medically significant arachnids due to its extensive geographic distribution in the United States and its ability to produce a potent neurotoxin, α-latrotoxin. This study aimed to describe the epidemiology of black widow spider exposures by month of exposure, geographic distribution, demographics, symptoms, treatment, and health system resource utilization between 2012 and 2022.MethodsThis was a retrospective observational study using the US National Poison Data System, the data warehouse of the 55 US poison centers. A descriptive analysis of patient demographic data, month of exposure, clinical effects, level of healthcare received, and medical outcome was performed.ResultsDuring the studied period, a total of 15,299 cases of Latrodectus spp exposures were reported to US poison centers. Exposures occurred with higher frequency in warm-weather states and during summer months. Almost half the cases were managed outside a healthcare facility (48.6%). Hospital admission was required for 10.0% of exposures. The most common therapies received were wound care (43.7%) and benzodiazepines (18.6%). Antivenom was administered in 3.4% (n=521) of exposures.ConclusionsPoison center data indicate that most black widow spider exposures result in minor consequences. Supportive care is the primary approach for black widow spider bites. Although antivenom use is infrequent, providers may seek administration guidance from toxicologists through local poison centers. This study underscores the pivotal role of poison centers in mitigating unnecessary healthcare visits and subsequent hospitalizations.

The poison ivy does not normally occur in Slovakia, like in the Czech Republic, but it can be introduced. The venom of the black widow spider is an effective weapon for capturing prey. It is a mixture of various active substances containing a protein neurotoxin called α-latrotoxin (α-LTX). Necrotizing fasciitis (NF) is a rapidly progressive soft tissue infection caused by fulminant tissue destruction with severe systemic toxicity and high mortality (Fig. 9, Ref. 16). Keywords: poisonous weaver, necrotizing fasciitis, streptococcus pyogenes, latrodectism, multiorgan failure.

Poecilotheria spiders are considered theraphosids of underestimated clinical importance, with bites from these species inducing symptoms such as severe pain and intense muscle cramps. However, there is no specific treatment for the envenomation caused by these species, which, while native to India and Sri Lanka, are widely distributed worldwide. The present study reports the case of a 31-year-old man bitten by a Poecilotheria regalis specimen. The patient's clinical presentation was similar to Latrodectus envenomation, and patient was treated with an L. mactans antivenom. Most of patient's symptoms improved (fasciculations, pain, erythema, and local swelling), except muscle cramps. A toxicological study conducted on mice did not show that L. mactans antivenom has a neutralizing effect on the toxicity of P. regalis. The present report discusses the envenoming process of Poecilotheria species and the possible neutralizing effect exerted by L. mactans antivenom.

Poisoning by widow-spider (genus Latrodectus) bites occurs worldwide. The illness, termed latrodectism, can cause severe and persistent pain and can lead to muscle rigidity, respiratory complications, and cardiac problems. It is a global health challenge especially in developing countries. Equine serum-derived polyclonal anti-sera are commercially available as a medication for patients with latrodectism, but the use of sera imposes potential inherent risks related to its animal origin. The treatment may cause allergic reactions in humans (serum sickness), including anaphylactic shock. Furthermore, equine-derived antivenom is observed to have batch-to-batch variability and poor specificity, as it is always an undefined mix of antibodies. Because latrodectism can be extremely painful but is rarely fatal, the use of antivenom is controversial and only a small fraction of patients is treated. In this work, recombinant human antibodies were selected against alpha-latrotoxin of the European black widow (Latrodectus tredecimguttatus) by phage display from a naïve antibody gene library. Alpha-Latrotoxin (α-LTX) binding scFv were recloned and produced as fully human IgG. A novel alamarBlue assay for venom neutralization was developed and used to select neutralizing IgGs. The human antibodies showed in vitro neutralization efficacy both as single antibodies and antibody combinations. This was also confirmed by electrophysiological measurements of neuronal activity in cell culture. The best neutralizing antibodies showed nanomolar affinities. Antibody MRU44-4-A1 showed outstanding neutralization efficacy and affinity to L. tredecimguttatus α-LTX. Interestingly, only two of the neutralizing antibodies showed cross-neutralization of the venom of the Southern black widow (Latrodectus mactans). This was unexpected, because in the current literature the alpha-latrotoxins are described as highly conserved. The here-engineered antibodies are candidates for future development as potential therapeutics and diagnostic tools, as they for the first time would provide unlimited supply of a chemically completely defined drug of constant quality and efficacy, which is also made without the use of animals.

Black widow spiders (BWSs) are poisonous spiders of the Arthropoda phylum that live in the Mediterranean region. The effects of BWS bites ranges from local damage to systemic manifestations including paresthesia, stiffness, abdominal cramps, nausea, vomiting, headache, anxiety, hypertension and tachycardia. However, cardiac involvement following a BWS bite is uncommon. We report a 35-year-old male patient who presented to a tertiary hospital in Menoufia, Egypt, in 2019 and developed acute pulmonary oedema with electrocardiogram (ECG) changes that showed ST elevation in leads I and aVL with reciprocal ST segment depression in infero-lateral leads with elevated cardiac biomarkers. Echocardiography showed regional wall motion abnormalities with an impaired ejection fraction of 42%. The condition was reversible after one week of supportive treatment and the patient was discharged from the hospital with normal electrocardiogram, ejection fraction and negative cardiac markers. A routine cardiac evaluation, serial ECG, serial cardiac markers and echocardiography should be considered for any patient exposed to a BWS bite for detection of any potentially fatal cardiac abnormalities.

The genus Latrodectus contains the most medically important spiders around the world. This study describes the first case of Latrodectus cinctus Blackwall, 1865 bite and clinical treatment from Iran. Also, it is the first collection report from the southeast of the country that can enhance prior knowledge on the geographical distribution of this species. We describe a 42-year-old female patient with neurological pain caused by the spider bite. Also, a summary of the entomological survey and morphological identification of the collected species from the patient's house is presented.

This game is appropriate for medical students, interns, junior and senior residents.

Latrodectism from black widow spider (BWS) bites is rare in the United States. Latrodectism is a severe systemic manifestation of the envenomation that includes severe abdominal pain mimicking acute surgical abdomen and, in rare cases, could lead to acute myocarditis and rhabdomyolysis. The BWS typically inhabits dark, low-lying areas such as woodpiles, tree stumps, outdoor storage, outdoor furniture, outdoor toilets, and rock piles and is most active during warm weather months. Military service members often participate in field training exercises during warm weather in wooded areas littered with woodpiles and tree stumps; therefore, they are at an increased risk for bites by arachnids. We report the case of a 26-year-old active duty male soldier evacuated from field training with latrodectism and possible envenomation-induced myocarditis after a suspected BWS bite.

Black widow spiders are distributed worldwide and, although rarely fatal, account for significant morbidity. Diagnosis can be challenging, and children are at risk of increased morbidity due to their small size.