Bothrops envenomation in dogs: local and systemic manifestations

Background: Snakebite envenoming is a condition that affects humans and domestic animals worldwide. Identification of the snake species involved in the envenomation is infrequent. Bothrops envenomation presents typical clinicopathological features. This report describes epidemiological, clinical, and pathological data of 2 cases of Bothrops envenomation in dogs, including the first case of Bothrops moojeni snake striking a domestic animal in Brazil. Cases: Case 1. A dog was witnessed to have a Bothrops moojeni snakebite on a farm. In the first 24 h, acute lameness, pain, diffuse swelling, focal bleeding at the left forelimb, and increased whole-blood clotting time were observed in the envenomed dog. Polyvalent antivenom was administered in addition to fluid therapy, analgesics, corticosteroids, and antibiotics. On the 5th day, the animal presented spontaneous bleeding at the wound site, thrombocytopenia, and increased whole-blood clotting time. An additional dose of polyvalent antivenom was administered, and local treatment at the snakebite site was initiated. After 13 days, the dog showed no clinical or laboratory changes and recovered entirely. Case 2. A mongrel dog was taken for a necropsy to determine the cause of death. Grossly, major findings included swelling in the nasal plane that extended to the neck and dissecting hemorrhage in the subcutaneous tissue and adjacent musculature. Hemorrhages were observed in the heart, parietal pleura, left forelimb, lumbar region, and perirenal tissue. Marked necrosis and disruption of small blood vessels and lymphatics within the deep dermis and subcutaneous tissue were the main microscopic findings close to the snakebite site. Additionally, degeneration and necrosis of muscle fibers and dissecting hemorrhage were observed in the head and neck tissues surrounding the snakebite site. Kidneys showed marked interstitial hemorrhage and acute tubular nephrosis. Discussion: Bothrops envenoming is characterized by local (hemorrhage, dermonecrosis, and myonecrosis) and systemic (coagulative disorders, systemic hemorrhage, and acute kidney injury) changes due to the effect of the main venom components such as phospholipase A2 and metalloproteinases. These changes are hallmarks for the bothropic envenomation, supporting the diagnosis in cases 1 and 2. In case 1, the dog developed a Bothrops moojeni snakebite envenomation, but the immediate treatment with antivenom allowed a favorable outcome. In case 2, gross and microscopic findings supported the presumptive diagnosis of fatal bothropic envenomation. A marked local reaction such as swelling, pain, bleeding, bruising, and tissue necrosis was observed in case 1. In case 2, the most significant local changes were swelling and edema at the head and neck, hemorrhage in the subcutaneous tissue, and adjacent musculature. Systemic effects were observed clinically as spontaneous bleeding, thrombocytopenia, increased whole-blood clotting time (Case 1), systemic hemorrhages, and acute tubular nephrosis (Case 2). A proper treatment probably prevented the development of acute renal failure in Case 1. Herein, we show the first case of accidental snakebite envenomation by B. moojeni in a dog in Brazil. Information is scarce on the identification of venomous snake species striking domestic animals. Fast detection of well-determined clinical and pathological findings of Bothrops envenomation is essential for a correct diagnosis, therapeutics, and a good prognosis, even in cases with an unknown history.

Effects of copaiba oil on dermonecrosis induced by Loxosceles intermedia venom

Background:Accidents caused by spiders of the genus Loxosceles constitute an important public health problem in Brazil. The venom of Loxosceles sp induces dermonecrosis at the bite site and systemic disease in severe cases. Traditional medicine based on plant-derived products has been proven to reduce the local effects of envenomation. The present study verified the healing effects of copaiba oil on lesions induced by the venom of L. intermedia.Methods:Cutaneous lesions were induced on the backs of rabbits by intradermal injection of L. intermedia venom. Copaiba oil was applied topically 6 hours after injection; the treatment was repeated for 30 days, after which animal skins were removed and processed for histopathological analysis. Blood samples were also collected before and 24 hours after venom inoculation to measure the hematological parameters.Results:Compared to the control group, the platelet count was reduced significantly in all groups inoculated with venom, accompanied by a decreased number of heterophils in the blood. The minimum necrotic dose (MND) was defined as 2.4 μg/kg. Topical treatment with copaiba oil demonstrated a differentiated healing profile: large skin lesions were observed 10 days after venom inoculation, whereas formation of a thick crust, without scarring was observed 30 days after venom inoculation. Histopathological analysis showed no significant difference after treatment. Nevertheless, the copaiba oil treatment induced a collagen distribution similar to control skin, in marked contrast to the group that received only the spider venom injection.Conclusions:We conclude that copaiba oil may interfere in the healing process and thus propose it as a possible topical treatment for cutaneous lesions induced by L. intermedia venom.(AU)

Effects of copaiba oil on dermonecrosis induced by Loxosceles intermedia venom

Accidents caused by spiders of the genus Loxosceles constitute an important public health problem in Brazil. The venom of Loxosceles sp induces dermonecrosis at the bite site and systemic disease in severe cases. Traditional medicine based on plant-derived products has been proven to reduce the local effects of envenomation. The present study verified the healing effects of copaiba oil on lesions induced by the venom of L. intermedia. Methods: Cutaneous lesions were induced on the backs of rabbits by intradermal injection of L. intermedia venom. Copaiba oil was applied topically 6 hours after injection; the treatment was repeated for 30 days, after which animal skins were removed and processed for histopathological analysis. Blood samples were also collected before and 24 hours after venom inoculation to measure the hematological parameters. Results: Compared to the control group, the platelet count was reduced significantly in all groups inoculated with venom, accompanied by a decreased number of heterophils in the blood. The minimum necrotic dose (MND) was defined as 2.4 μg/kg. Topical treatment with copaiba oil demonstrated a differentiated healing profile: large skin lesions were observed 10 days after venom inoculation, whereas formation of a thick crust, without scarring was observed 30 days after venom inoculation. Histopathological analysis showed no significant difference after treatment. Nevertheless, the copaiba oil treatment induced a collagen distribution similar to control skin, in marked contrast to the group that received only the spider venom injection. Conclusions: We conclude that copaiba oil may interfere in the healing process and thus propose it as a possible topical treatment for cutaneous lesions induced by L. intermedia venom.(AU)

Lesão dermonecrótica em um gato atribuída a envenenamento por Loxosceles - relato de caso / Dermonecrotic lesion in a cat attributed to Loxosceles envenomation – case report

Os acidentes causados por aranhas do gênero Loxosceles têm importância na clínica de pequenos animais, mesmo não havendo dados epidemiológicos desses ataques em animais de estimação, dada a gravidade da lesão e possíveis complicações sistêmicas resultantes, tornando indispensável maior conhecimento sobre a espécie e as consequências do envenenamento. O presente trabalho relata a presença de uma lesão dermonecrótica em um felino atribuída a aranha-marrom (Loxosceles sp). O atendimento ocorreu na clínica Empório de Bicho em Caxias do Sul, no estado do Rio Grande do Sul. O animal apresentava uma lesão necrótica em região perineal, com fibrina e secreção purulenta. O tratamento consistiu no uso clorexidina para limpeza, hidrogel, açúcar, Fitofix® e Dersani® como promotores de cicatrização. Após um mês de tratamento, o animal apresentava uma melhora satisfatória.

Accidents caused by spiders of the genus Loxosceles are important in the small animal clinic, even though there are no epidemiological data on these attacks in pets, given the severity of the lesion and possible systemic complications, it becomes necessary to know more about the species and the consequences of the poisoning. The present work reports the presence of a dermonecrotic lesion in a cat attributed to brown spider (Loxosceles sp). The patient had a necrotic lesion in the perineal region with fibrin and purulent secretion. The treatment consisted of using chlorhexidine for cleaning, hydrogel, sugar, Fitofix® and Dersani® as healing promoters. After one month of treatment, the animal showed a satisfactory improvement.

Lesão dermonecrótica em um gato atribuída a envenenamento por Loxosceles - relato de caso / Dermonecrotic lesion in a cat attributed to Loxosceles envenomation case report

Os acidentes causados por aranhas do gênero Loxosceles têm importância na clínica de pequenos animais, mesmo não havendo dados epidemiológicos desses ataques em animais de estimação, dada a gravidade da lesão e possíveis complicações sistêmicas resultantes, tornando indispensável maior conhecimento sobre a espécie e as consequências do envenenamento. O presente trabalho relata a presença de uma lesão dermonecrótica em um felino atribuída a aranha-marrom (Loxosceles sp). O atendimento ocorreu na clínica Empório de Bicho em Caxias do Sul, no estado do Rio Grande do Sul. O animal apresentava uma lesão necrótica em região perineal, com fibrina e secreção purulenta. O tratamento consistiu no uso clorexidina para limpeza, hidrogel, açúcar, Fitofix® e Dersani® como promotores de cicatrização. Após um mês de tratamento, o animal apresentava uma melhora satisfatória.(AU)

Accidents caused by spiders of the genus Loxosceles are important in the small animal clinic, even though there are no epidemiological data on these attacks in pets, given the severity of the lesion and possible systemic complications, it becomes necessary to know more about the species and the consequences of the poisoning. The present work reports the presence of a dermonecrotic lesion in a cat attributed to brown spider (Loxosceles sp). The patient had a necrotic lesion in the perineal region with fibrin and purulent secretion. The treatment consisted of using chlorhexidine for cleaning, hydrogel, sugar, Fitofix® and Dersani® as healing promoters. After one month of treatment, the animal showed a satisfactory improvement.(AU)

Highlights in the knowledge of brown spider toxins

Abstract Brown spiders are venomous arthropods that use their venom for predation and defense. In humans, bites of these animals provoke injuries including dermonecrosis with gravitational spread of lesions, hematological abnormalities and impaired renal function. The signs and symptoms observed following a brown spider bite are called loxoscelism. Brown spider venom is a complex mixture of toxins enriched in low molecular mass proteins (440 kDa). Characterization of the venom confirmed the presence of three highly expressed protein classes: phospholipases D, metalloproteases (astacins) and insecticidal peptides (knottins). Recently, toxins with low levels of expression have also been found in Loxosceles venom, such as serine proteases, protease inhibitors (serpins), hyaluronidases, allergen-like toxins and histamine-releasing factors. The toxin belonging to the phospholipase-D family (also known as the dermonecrotic toxin) is the most studied class of brown spider toxins. This class of toxins single-handedly can induce inflammatory response, dermonecrosis, hemolysis, thrombocytopenia and renal failure. The functional role of the hyaluronidase toxin as a spreading factor in loxoscelism has also been demonstrated. However, the biological characterization of other toxins remains unclear and the mechanism by which Loxosceles toxins exert their noxious effects is yet to be fully elucidated. The aim of this review is to provide an insight into brown spider venom toxins and toxicology, including a description of historical data already available in the literature. In this review article, the identification processes of novel Loxosceles toxins by molecular biology and proteomic approaches, their biological characterization and structural description based on x-ray crystallography and putative biotechnological uses are described along with the future perspectives in this field.

Rattlesnake Crotalus molossus nigrescens venom induces oxidative stress on human erythrocytes

Abstract Background Globally, snake envenomation is a well-known cause of death and morbidity. In many cases of snakebite, myonecrosis, dermonecrosis, hemorrhage and neurotoxicity are present. Some of these symptoms may be provoked by the envenomation itself, but others are secondary effects of the produced oxidative stress that enhances the damage produced by the venom toxins. The only oxidative stress effect known in blood is the change in oxidation number of Fe (from ferrous to ferric) in hemoglobin, generating methemoglobin but not in other macromolecules. Currently, the effects of the overproduction of methemoglobin derived from snake venom are not extensively recorded. Therefore, the present study aims to describe the oxidative stress induced by Crotalus molossus nigrescens venom using erythrocytes. Methods Human erythrocytes were washed and incubated with different Crotalus molossus nigrescens venom concentrations (0640 g/mL). After 24 h, the hemolytic activity was measured followed by attenuated total reflectance-Fourier transform infrared spectroscopy, non-denaturing PAGE, conjugated diene and thiobarbituric acid reactive substances determination. Results Low concentrations of venom ( 10 g/mL) generates oxyhemoglobin release by hemolysis, whereas higher concentrations produced a hemoglobin shift of valence, producing methemoglobin (>40 g/mL). This substance is not degraded by proteases present in the venom. By infrared spectroscopy, starting in 80 g/mL, we observed changes in bands that are associated with protein damage (1660 and 1540 cm1) and lipid peroxidation (2960, 2920 and 1740 cm1). Lipid peroxidation was confirmed by conjugated diene and thiobarbituric acid reactive substance determination, in which differences were observed between the control and erythrocytes treated with venom. Conclusions Crotalus molossus nigrescens venom provokes hemolysis and oxidative stress, which induces methemoglobin formation, loss of protein structure and lipid peroxidation.

Highlights in the knowledge of brown spider toxins

Abstract Brown spiders are venomous arthropods that use their venom for predation and defense. In humans, bites of these animals provoke injuries including dermonecrosis with gravitational spread of lesions, hematological abnormalities and impaired renal function. The signs and symptoms observed following a brown spider bite are called loxoscelism. Brown spider venom is a complex mixture of toxins enriched in low molecular mass proteins (4-40 kDa). Characterization of the venom confirmed the presence of three highly expressed protein classes: phospholipases D, metalloproteases (astacins) and insecticidal peptides (knottins). Recently, toxins with low levels of expression have also been found in Loxosceles venom, such as serine proteases, protease inhibitors (serpins), hyaluronidases, allergen-like toxins and histamine-releasing factors. The toxin belonging to the phospholipase-D family (also known as the dermonecrotic toxin) is the most studied class of brown spider toxins. This class of toxins single-handedly can induce inflammatory response, dermonecrosis, hemolysis, thrombocytopenia and renal failure. The functional role of the hyaluronidase toxin as a spreading factor in loxoscelism has also been demonstrated. However, the biological characterization of other toxins remains unclear and the mechanism by which Loxosceles toxins exert their noxious effects is yet to be fully elucidated. The aim of this review is to provide an insight into brown spider venom toxins and toxicology, including a description of historical data already available in the literature. In this review article, the identification processes of novel Loxosceles toxins by molecular biology and proteomic approaches, their biological characterization and structural description based on x-ray crystallography and putative biotechnological uses are described along with the future perspectives in this field.(AU)

Highlights in the knowledge of brown spider toxins

Brown spiders are venomous arthropods that use their venom for predation and defense. In humans, bites of these animals provoke injuries including dermonecrosis with gravitational spread of lesions, hematological abnormalities and impaired renal function. The signs and symptoms observed following a brown spider bite are called loxoscelism. Brown spider venom is a complex mixture of toxins enriched in low molecular mass proteins (4-40 kDa). Characterization of the venom confirmed the presence of three highly expressed protein classes: phospholipases D, metalloproteases (astacins) and insecticidal peptides (knottins). Recently, toxins with low levels of expression have also been found in Loxosceles venom, such as serine proteases, protease inhibitors (serpins), hyaluronidases, allergen-like toxins and histamine-releasing factors. The toxin belonging to the phospholipase-D family (also known as the dermonecrotic toxin) is the most studied class of brown spider toxins. This class of toxins single-handedly can induce inflammatory response, dermonecrosis, hemolysis, thrombocytopenia and renal failure. The functional role of the hyaluronidase toxin as a spreading factor in loxoscelism has also been demonstrated. However, the biological characterization of other toxins remains unclear and the mechanism by which Loxosceles toxins exert their noxious effects is yet to be fully elucidated. The aim of this review is to provide an insight into brown spider venom toxins and toxicology, including a description of historical data already available in the literature. In this review article, the identification processes of novel Loxosceles toxins by molecular biology and proteomic approaches, their biological characterization and structural description based on x-ray crystallography and putative biotechnological uses are described along with the future perspectives in this field.(AU)

Rattlesnake Crotalus molossus nigrescens venom induces oxidative stress on human erythrocytes

Background Globally, snake envenomation is a well-known cause of death and morbidity. In many cases of snakebite, myonecrosis, dermonecrosis, hemorrhage and neurotoxicity are present. Some of these symptoms may be provoked by the envenomation itself, but others are secondary effects of the produced oxidative stress that enhances the damage produced by the venom toxins. The only oxidative stress effect known in blood is the change in oxidation number of Fe (from ferrous to ferric) in hemoglobin, generating methemoglobin but not in other macromolecules. Currently, the effects of the overproduction of methemoglobin derived from snake venom are not extensively recorded. Therefore, the present study aims to describe the oxidative stress induced by Crotalus molossus nigrescens venom using erythrocytes. Methods Human erythrocytes were washed and incubated with different Crotalus molossus nigrescens venom concentrations (0-640 μg/mL). After 24 h, the hemolytic activity was measured followed by attenuated total reflectance-Fourier transform infrared spectroscopy, non-denaturing PAGE, conjugated diene and thiobarbituric acid reactive substances determination. Results Low concentrations of venom (<10 μg/mL) generates oxyhemoglobin release by hemolysis, whereas higher concentrations produced a hemoglobin shift of valence, producing methemoglobin (>40 μg/mL). This substance is not degraded by proteases present in the venom. By infrared spectroscopy, starting in 80 μg/mL, we observed changes in bands that are associated with protein damage (1660 and 1540 cm−1) and lipid peroxidation (2960, 2920 and 1740 cm−1). Lipid peroxidation was confirmed by conjugated diene and thiobarbituric acid reactive substance determination, in which differences were observed between the control and erythrocytes treated with venom. Conclusions Crotalus molossus nigrescens venom provokes hemolysis and oxidative stress, which induces methemoglobin formation, loss of protein structure and lipid peroxidation.(AU)

Rattlesnake Crotalus molossus nigrescens venom induces oxidative stress on human erythrocytes

Background Globally, snake envenomation is a well-known cause of death and morbidity. In many cases of snakebite, myonecrosis, dermonecrosis, hemorrhage and neurotoxicity are present. Some of these symptoms may be provoked by the envenomation itself, but others are secondary effects of the produced oxidative stress that enhances the damage produced by the venom toxins. The only oxidative stress effect known in blood is the change in oxidation number of Fe (from ferrous to ferric) in hemoglobin, generating methemoglobin but not in other macromolecules. Currently, the effects of the overproduction of methemoglobin derived from snake venom are not extensively recorded. Therefore, the present study aims to describe the oxidative stress induced by Crotalus molossus nigrescens venom using erythrocytes. Methods Human erythrocytes were washed and incubated with different Crotalus molossus nigrescens venom concentrations (0-640 μg/mL). After 24 h, the hemolytic activity was measured followed by attenuated total reflectance-Fourier transform infrared spectroscopy, non-denaturing PAGE, conjugated diene and thiobarbituric acid reactive substances determination. Results Low concentrations of venom (<10 μg/mL) generates oxyhemoglobin release by hemolysis, whereas higher concentrations produced a hemoglobin shift of valence, producing methemoglobin (>40 μg/mL). This substance is not degraded by proteases present in the venom. By infrared spectroscopy, starting in 80 μg/mL, we observed changes in bands that are associated with protein damage (1660 and 1540 cm−1) and lipid peroxidation (2960, 2920 and 1740 cm−1). Lipid peroxidation was confirmed by conjugated diene and thiobarbituric acid reactive substance determination, in which differences were observed between the control and erythrocytes treated with venom. Conclusions Crotalus molossus nigrescens venom provokes hemolysis and oxidative stress, which induces methemoglobin formation, loss of protein structure and lipid peroxidation.(AU)

Histopathological characterization of experimentally induced cutaneous loxoscelism in rabbits inoculated with Loxosceles similis venom

Envenomation by Loxosceles bites is characterized by dermonecrotic and/or systemic features that lead to several clinical signs and symptoms called loxoscelism. Dermonecrotic lesions are preceded by thrombosis of the dermal plexus. Recent studies show that atheromatous plaque is prone to thrombosis due to endothelial cell apoptosis. To the best of our knowledge, there are no reports of microscopic dermal lesion and endothelial cell apoptosis induced by Loxosceles similis venom in the literature. Thus, the aim of the present study is to describe histological lesions induced by L. similis venom in rabbit skin and to elucidate whether apoptosis of endothelial cells is involved in the pathogenesis of loxoscelism. Forty male rabbits were split into two groups: the control group (intradermally injected with 50 µL of PBS) and the experimental group (intradermally injected with 0.5 µg of L. similis crude venom diluted in 50 µL of PBS). After 2, 4, 6 and 8 hours of injection, skin fragments were collected and processed for paraffin or methacrylate embedding. Sections of 5 µm thick were stained by HE, PAS or submitted to TUNEL reaction. Microscopically, severe edema, diffuse heterophilic inflammatory infiltrate, perivascular heterophilic infiltrate, thrombosis, fibrinoid necrosis of arteriolar wall and cutaneous muscle necrosis were observed. Two hours after venom injection, endothelial cells with apoptosis morphology were evidenced in the dermal plexus. Apoptosis was confirmed by TUNEL reaction. It seems that endothelial cell apoptosis and its consequent desquamation is an important factor that induces thrombosis and culminates in dermonecrosis, which is characteristic of cutaneous loxoscelism.(AU)