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.

Reversible Myocarditis Following Black Widow Spider (Latrodectus spp.) Bite in Egypt: A case report.

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.

Severe complications in a 25-year-old male after brown recluse spider bite treated by therapeutic plasma exchange: A case report and review of other case studies.

Although in the majority of patients (90%), the bite wound of brown recluse spider resolves spontaneously, some patients may experience a severe reaction requiring hospitalization. A 25-year-old male developed severe hemolytic anemia, jaundice, and other complications following a brown recluse spider bite on his posterior right thigh. He was treated with methylprednisolone, antibiotics, and red blood cells (RBCs) transfusion without response. Therapeutic plasma exchange (TPE) was added to the treatment regimen, and his hemoglobin (Hb) was eventually stabilized, leading to significant clinical improvement. The beneficial effect of TPE in the current case was compared to three other reported cases. We recommend close monitoring of Hb levels in patients with systemic loxoscelism during the first week after brown recluse spider bite and early implementation of TPE in the management of severe acute hemolysis when patients do not respond to usual treatment modalities and RBC transfusion.

Arthropod Bites and Stings.

Arthropods, including insects and arachnids, significantly affect humans as vectors for infectious diseases. Arthropod bites and stings commonly cause minor, usually self-limited reactions; however, some species are associated with more severe complications. Spider bites are rarely life-threatening. There are two medically relevant spiders in the United States. Widow spider (Latrodectus) envenomation can cause muscle spasm and severe pain that should be treated with analgesics and benzodiazepines. Antivenom is not widely available in the United States but may be considered for severe, refractory cases. Recluse spider (Loxosceles) bites are often overdiagnosed, should be treated supportively, and only rarely cause skin necrosis. Centruroides scorpions are the only medically relevant genus in the United States. Envenomation causes neuromuscular and autonomic dysfunction, which should be treated with analgesics, benzodiazepines, supportive care, and, in severe cases, antivenom. Hymenoptera, specifically bees, wasps, hornets, and fire ants, account for the most arthropod-related deaths in humans, most commonly by severe allergic reactions to envenomation. In severe cases, patients are treated with analgesia, local wound care, and systemic glucocorticoids. Diptera include flies and mosquitoes. The direct effects of their bites are usually minor and treated symptomatically; however, they are vectors for numerous infectious diseases. Arthropod bite and sting prevention strategies include avoiding high-risk areas, covering exposed skin, and wearing permethrin-impregnated clothing. N,N-diethyl- m-toluamide (DEET) 20% to 50% is the most studied and widely recommended insect repellant.

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

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.

Brown spider (Loxosceles sp.) bite and COVID-19: A case report.

We present the case of a 32-year-old male patient hospitalized during the COVID-19 pandemic because of a Brown spider bite on his lower lip. The Brown spider accident occurred in southern Brazil; at hospital admission, the patient presented on his lip: edema, pustules, necrotic regions, and ulcerations. The patient complained of lower back pain, fever and dyspnea. Laboratory tests showed monocytosis, leukocytosis, neutrophilia, increased D-dimer levels, C-reactive protein, glutamate-pyruvate transaminase, delta bilirubin, creatine phosphokinase, procalcitonin, and fibrinogen. The patient was hospitalized and a multi-professional team carried out the treatment. The medical team diagnosed loxoscelism with moderate changes. The dentist treated the oral cavity. The patient began to develop nausea, vomiting, and desaturation episodes during hospitalization. A computed tomography of the chest was performed, which showed signs of viral infection. The RT-PCR test for COVID-19 was positive. The systemic conditions worsened (renal dysfunction, systemic inflammatory response, pulmonary complications). This condition may have resulted from the association of the two diseases (loxoscelism and COVID-19), leading to the patient's death. This case illustrates the difficulties and risks in treating patients with venomous animal accidents during the pandemic, and the importance of a multi-professional team in treating such cases.

Hitchhiking spider: a case of unilateral vasculitis.

A 63-year-old man presented with two days of palpable purpura over the right anterior shin and calf with notable point tenderness on the distal mid-calf without any palpable deep abnormality. Localized right calf pain worsened with walking and was associated with headache, chills, fatigue, and low-grade fevers. A punch biopsy of the anterior right lower leg showed necrotizing neutrophilic vasculitis of superficial and deep vessels. Direct immunofluorescence showed non-specific focal granular deposition of C3 within vessel walls. Three days after presentation, a live spider was found and microscopically identified as a male hobo spider. The patient suspected the spider arrived via packages shipped from Seattle, Washington. The patient was treated with a prednisone taper with full resolution of his cutaneous symptoms. Given the unilaterality of his symptoms and otherwise unexplained etiology, the patient was diagnosed with acute unilateral vasculitis secondary to hobo spider bite. Microscopic examination is required for identification of hobo spiders. Although not deadly, there have been several reports of cutaneous and systemic reactions resulting from hobo spider bites. Our case illustrates the importance of considering hobo spider bites in areas outside of their native regions, as they are known to travel in packaged items.

Suspected Brown Recluse Spider Envenomation: Missed Diagnosis and Delayed Treatment of Loxoscelism: A Case Report.

CASE: We report the case of a previously healthy 51-year-old man who presented to our hospital after worsening clinical appearance of his left ring finger, despite antibiotics and previous surgical drainage for suspected abscess at an outside institution 3 weeks ago. He was admitted to our hospital for surgical debridement and decompression. After suspicion of cutaneous loxoscelism based on the clinical record and corticosteroid administration, the patient presented a favorable evolution. CONCLUSION: Cutaneous loxoscelism caused by a spider bite is present in Europe, mainly in the Mediterranean area, and should be considered in cases of skin infections which do not respond to antibiotics.

Venomous Snake and Spider Bites in Pregnancy.

IMPORTANCE: Venomous snake and spider bites are relatively rare in the Unites States and even more so in the pregnant population. However, the impact of a venomous bite, also known as an envenomation, can be serious in a pregnant patient. Thus, providers in endemic and high-risk areas must be familiar with the management of envenomation in the pregnant population. OBJECTIVE: The purpose of this article is to review the current literature on the most common snake and spider envenomations in the United States, the effects of envenomation on maternal and fetal health, and the management of envenomation in pregnancy. EVIDENCE ACQUISITION: Original research articles, review articles, and guidelines on snake and spider envenomation were reviewed. RESULTS: Snake envenomation carries higher risks of maternal morbidity and fetal morbidity and mortality than spider envenomation. Although the data are limited, current literature suggests that both snake and spider antivenom can be used in the pregnant population without significant adverse outcomes. However, the risks of an adverse hypersensitivity reaction with antivenom administration should be weighed carefully with the benefits. CONCLUSIONS AND RELEVANCE: The use of antivenom therapy in the symptomatic envenomated pregnant population is likely safe with the appropriate monitoring and follow-up. Knowledge of the indications for antivenom therapy and proper escalation of care are vital to optimizing maternal and fetal outcomes. More research is needed to determine the effects of both envenomation and antivenom therapy on the pregnant patient and their fetus.

[Loxoscelism. Experience in 200 patients]. / Caracterización clínica y epidemiológica de 200 pacientes con loxoscelismo cutáneo y cutáneo visceral.

BACKGROUND: Loxoscelism is an important public health problem in Chile and South America, due to the higher rate of cutaneous-visceral involvement. The diagnosis of loxoscelism is mostly clinical without established diagnostic criteria. There is little evidence to support any treatment used in this condition. AIM: To characterize the clinical features and epidemiology of loxoscelism among patients consulting at the Emergency and Dermatology Services of a clinical hospital between 2013 and 2017. MATERIAL AND METHODS: Review of medical records of patients registered in the electronic clinical record system with a confirmed diagnosis of loxoscelism. Epidemiological, clinical, laboratory tests and treatment variables were analyzed. RESULTS: We reviewed data from 200 patients. Ninety-four percent presented cutaneous loxoscelism and 5.5% cutaneous-visceral loxoscelism. Systemic symptoms were present in 73% of patients with cutaneous-visceral loxoscelism. Patients who developed systemic symptoms had an 18 times higher risk of developing cutaneous-visceral loxoscelism. Laboratory abnormalities were more common in patients with cutaneous-visceral loxoscelism. Not all patients with hematuria had cutaneous-visceral loxoscelism. Most patients required analgesia. Anti-loxosceles serum was not used in any patient. CONCLUSIONS: Many questions remain to be answered regarding the diagnosis and treatment of the disease. Studies are required to validate diagnostic criteria for loxoscelism, predictors for visceral involvement and response to treatment.

A protective vaccine against the toxic activities following Brown spider accidents based on recombinant mutated phospholipases D as antigens.

Accidents involving Brown spiders are reported throughout the world. In the venom, the major toxins involved in the deleterious effects are phospholipases D (PLDs). In this work, recombinant mutated phospholipases D from three endemic species medically relevant in South America (Loxosceles intermedia, L. laeta and L. gaucho) were tested as antigens in a vaccination protocol. In such isoforms, key amino acid residues involved in catalysis, magnesium-ion coordination, and binding to substrates were replaced by Alanine (H12A-H47A, E32A-D34A and W230A). These mutations eliminated the phospholipase activity and reduced the generation of skin necrosis and edema to residual levels. Molecular modeling of mutated isoforms indicated that the three-dimensional structures, topologies, and surface charges did not undergo significant changes. Mutated isoforms were recognized by sera against the crude venoms. Vaccination protocols in rabbits using mutated isoforms generated a serum that recognized the native PLDs of crude venoms and neutralized dermonecrosis and edema induced by L. intermedia venom. Vaccination of mice prevented the lethal effects of L. intermedia crude venom. Furthermore, vaccination of rabbits prevented the cutaneous lesion triggered by the three venoms. These results indicate a great potential for mutated recombinant PLDs to be employed as antigens in developing protective vaccines for Loxoscelism.

Key to medically relevant Italian spider bites: a practical quick recognition tool for clinicians.

INTRODUCTION: Spider bites are often overestimated because there are no specific clinical or histopathological aspects that characterize them, and skin lesions that resemble a spider bite are often wrongly considered to be a "true spider bite". However, even in case of a true spider bite, it is almost impossible to confirm the biting species, since very often neither physicians nor patients are trained in spider identification. OBJECTIVE: The aim of this report is to provide clinicians with a rapid and simple recognition of the few Italian medically relevant spiders, in order to take relative medical measures in case of spider bites. MATERIALS AND METHODS: We defined spiders of considerable medical relevance the ones that cause local symptoms with possible systemic involvement, while we defined spiders with mild medical relevance the ones whose bite is not a medical emergency but is particularly painful or can cause lasting symptoms. We focused on the identification of the four spider taxa of major clinical interest through a brief descriptive, photographic and graphic guide, in association to dermatological manifestations. RESULTS: Spiders of considerable medical relevance are Loxosceles rufescens and Latrodectus tredecimguttatus, while spiders of less severe medical relevance are Steatoda paykulliana, S. nobilis, S. grossa, Cheiracanthium punctorium, Amblyocarenum spp. and Macrothele calpeiana (the presence of the latter in Italy is only accidental and very sporadic). The only species capable of causing necrosis is Loxo-sceles rufescens, while Latrodectus tredecimguttatus can cause more systemic symptoms. DISCUSSION AND CONCLUSION: With the aim of promoting a first and rapid recognition of the species, we performed a morphological usable aspect for an initial and quick recognition according to an identification key.

Caracterización clínica y epidemiológica de 200 pacientes con loxoscelismo cutáneo y cutáneo visceral / Loxoscelism: experience in 200 patients

Background: Loxoscelism is an important public health problem in Chile and South America, due to the higher rate of cutaneous-visceral involvement. The diagnosis of loxoscelism is mostly clinical without established diagnostic criteria. There is little evidence to support any treatment used in this condition. Aim: To characterize the clinical features and epidemiology of loxoscelism among patients consulting at the Emergency and Dermatology Services of a clinical hospital between 2013 and 2017. Material and Methods: Review of medical records of patients registered in the electronic clinical record system with a confirmed diagnosis of loxoscelism. Epidemiological, clinical, laboratory tests and treatment variables were analyzed. Results: We reviewed data from 200 patients. Ninety-four percent presented cutaneous loxoscelism and 5.5% cutaneous-visceral loxoscelism. Systemic symptoms were present in 73% of patients with cutaneous-visceral loxoscelism. Patients who developed systemic symptoms had an 18 times higher risk of developing cutaneous-visceral loxoscelism. Laboratory abnormalities were more common in patients with cutaneous-visceral loxoscelism. Not all patients with hematuria had cutaneous-visceral loxoscelism. Most patients required analgesia. Anti-loxosceles serum was not used in any patient. Conclusions: Many questions remain to be answered regarding the diagnosis and treatment of the disease. Studies are required to validate diagnostic criteria for loxoscelism, predictors for visceral involvement and response to treatment.

[Venomous Animals in the Portuguese Territory: Clinical Management of Bites and Stings]. / Animais Venenosos em Território Português: Abordagem Clínica de Picadas e Mordeduras.

There are many native species of animals with the potential to cause severe disease in Portugal. Of the four clinically relevant snake species, the vipers (Vipera latastei and Vipera seoanei) are the most concerning. They can cause severe disease and require in-hospital management, monitoring and specific treatment, including the administration of anti-snake venom serum. The Malpolon monspessulanus and Macroprotodon brevis snakes cause mostly localized clinical manifestations, which do not require specific treatment. Only a minority of the spider species in Portugal possess chelicerae (mouthparts of the Chelicerata, shaped as either articulated fangs or pincers, which may contain venom or be connected to the venom glands and are used for predation or capture of food) long enough to perforate the human skin. Nevertheless, Latrodectus tredecimguttatus and Loxosceles rufescens spider bites may require specialized treatment in a hospital setting, as well as careful active symptom surveillance. Diversely, the treatment for Scolopendra cingulata and Scolopendra oraniensis centipedes' bites is merely symptomatic. The only existing scorpion species in Portugal is the Buthus ibericus; its sting typically causes local symptoms with intense pain, and its treatment consists essentially of analgesia. The insects of the Hymenoptera order, such as bees and wasps, have the ability to inject venom into the skin. Most people present only with local or regional inflammatory response, and symptomatic treatment is usually effective. Even so, individuals with hypersensitivity to bee venom may develop anaphylaxis. Several marine species in the Portuguese coast are venomous to humans, including weeverfish (Trachinidae family), stingrays (Dasyatis pastinaca, Taeniura grabata, Myliobatis aquila), red scorpion fish (Scorpaena scrofa), cnidaria (Pelagia noctiluca, Chrysaora hysoscella, Physalia physalis) and bearded fireworm (Hermodice carunculata); treatment is symptomatic. Contact with the larvae or bristles (chitinous structures with locomotor or tactile functions) of Thaumetopoea pityocampa (pine processionary) can cause cutaneous, ocular and, rarely, respiratory reactions; its management is also symptomatic.

Em território português, existem várias espécies autóctones de animais capazes de provocar envenenamento e doença clinicamente significativa, com potencial de gravidade. Das quatro espécies de serpentes com relevância clínica, as víboras (Vipera latastei e Vipera seoanei) são as mais preocupantes; podem causar doença grave e necessitam de abordagem hospitalar, monitorização e tratamento específico, incluindo soro antiveneno. As serpentes Malpolon monspessulanus e Macroprotodon brevis causam maioritariamente manifestações clínicas locais, sem tratamento específico. Apenas uma minoria das espécies de aranha presentes em Portugal possui quelíceras (apêndices bucais dos Chelicerata, em forma de tenaz ou gancho, que podem conter veneno ou encontrar-se ligados às glândulas venenosas, usados para predação ou captura de alimentos) suficientemente compridas para perfurar a pele humana, mas as picadas de Latrodectus tredecimguttatus e Loxosceles rufescens podem implicar tratamento diferenciado em ambiente hospitalar, com necessidade de vigilância ativa. O tratamento da picada das centopeias Scolopendra cingulata e Scolopendra oraniensis é sintomático. A única espécie de escorpião presente em território nacional, Buthus ibericus, causa geralmente sintomas locais com dor intensa; o tratamento habitualmente baseia-se apenas na administração de analgesia. Os insetos da ordem Hymenoptera, como as abelhas e vespas, possuem capacidade de libertar veneno através de picadas; a maior parte dos indivíduos apresenta apenas reações inflamatórias locais ou regionais, para as quais a aplicação de medidas sintomáticas é suficiente, mas indivíduos que apresentem hipersensibilidade ao veneno podem desenvolver reações anafiláticas. Na costa portuguesa e em águas pouco profundas, encontram-se várias espécies marinhas venenosas para os humanos, como Echiichthys vipera (peixe-aranha comum), Dasyatis pastinaca, Taeniura grabata e Myliobatis aquila (ratões), Scorpaena scrofa (rascasso-vermelho), Pelagia noctiluca, Chrysaora hysoscella e Physalia physalis (cnidários) e Hermodice carunculata (verme-do-fogo), cujas picadas necessitam apenas de tratamento sintomático. O contacto com as larvas ou cerdas (estruturas quitinosas com funções locomotoras ou tácteis) de Thaumetopoea pityocampa (lagarta-do-pinheiro) pode provocar reações cutâneas, oculares e, raramente, respiratórias; a sua abordagem também é sintomática.

A loxoscelism case received therapeutic apheresis and hyperbaric oxygen therapy.

Loxosceles reclusa (L.reclusa) is known to bite humans, and its venom includes several enzymes that cause clinical symptoms. Loxoscelism, a condition due to being bitten by Loxosceles spiders, commonly known as recluses, can involve a range of clinical conditions, from local cutaneous lesions to severe systemic involvement. The diagnosis of loxoscelism is usually made by anamnesis and clinical findings. Magnetic resonance imaging is recommended for patients at high risk of necrotizing fasciitis. Treatment modalities are still controversial and there is no standardized treatment approach. Reported here, our case of loxoscelism involved a 24-year-old man presenting with a Loxosceles spider bite, dermonecrotic lesion, vomiting, diarrhea, acute renal injury, and rhabdomyolysis, who was successfully treated with hyperbaric oxygen therapy, therapeutic apheresis, hemodialysis, wound debridement, and cutaneous autografting. Early diagnosis and multidisciplinary approach can be life-saving in spider bites that can cause systemic involvement. Loxoscelism should be considered in patients with skin necrosis, acute renal injury, and rhabdomyolysis.

A rare cause of secondary hemophagocytic lymphohistiocytosis: systemic loxoscelism.

BACKGROUND: Loxoscelism is caused by the bite of a specific spider type called the Loxosceles genus. In Turkey, most cases are seen after L. rufescens bites. Clinical manifestation of the bites ranges from local cutaneous reaction to severe ulcerative necrosis. Systemic loxoscelism may also occur. CASE: Herein, we report a previously healthy five-year-old male patient who developed a secondary hemophagocytic lymphohistiocytosis after a presumed brown spider bite. He was treated with dexamethasone. Within the following 14 days, hemophagocytic syndrome resolved. Local hyperbaric oxygen therapy was applied to the necrotic areas. CONCLUSION: Secondary hemophagocytic lymphohistiocytosis may develop after systemic loxoscelism. In the presence of persistent fever, hepatosplenomegaly and laboratory findings this clinical entity should be kept in mind.

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.

Loxoscelism: Advances and Challenges in the Design of Antibody Fragments with Therapeutic Potential.

Envenoming due to Loxosceles spider bites still remains a neglected disease of particular medical concern in the Americas. To date, there is no consensus for the treatment of envenomed patients, yet horse polyclonal antivenoms are usually infused to patients with identified severe medical conditions. It is widely known that venom proteins in the 30-35 kDa range with sphingomyelinase D (SMasesD) activity, reproduce most of the toxic effects observed in loxoscelism. Hence, we believe that monoclonal antibody fragments targeting such toxins might pose an alternative safe and effective treatment. In the present study, starting from the monoclonal antibody LimAb7, previously shown to target SMasesD from the venom of L. intermedia and neutralize its dermonecrotic activity, we designed humanized antibody V-domains, then produced and purified as recombinant single-chain antibody fragments (scFvs). These molecules were characterized in terms of humanness, structural stability, antigen-binding activity, and venom-neutralizing potential. Throughout this process, we identified some blocking points that can impact the Abs antigen-binding activity and neutralizing capacity. In silico analysis of the antigen/antibody amino acid interactions also contributed to a better understanding of the antibody's neutralization mechanism and led to reformatting the humanized antibody fragment which, ultimately, recovered the functional characteristics for efficient in vitro venom neutralization.