Snake bites recorded by veterinary practices in Australia

Objective To determine the extent of the snake bite problem in domestic animals, its regional significance and the effects of antivenom treatment.
Design A questionnaire was designed seeking information on the number and type of domestic animals referred, whether treated or untreated, type of snakes and management of the bite.
Procedure The survey form was sent to 10% of veterinary surgeons, selected at random throughout Australia.
Results The response of 106 veterinary surgeons revealed that snake bite in domestic animals is frequent, with an estimated 6200 cases reported annually. Bites were more prominent in rural (78%) than urban areas (22%) with brown, tiger and black snakes accounting for 76%, 13% and 6% of cases, respectively. Cats and dogs were the most frequently reported victims. Ninety-one percent of cats and 75% of dogs survived following the administration of antivenom whereas 66% of cats and 31% of dogs survived without antivenom. Overall, in 33% of cases antivenom was not used, and venom detection kits were used in only 1% of cases. A number of drugs were used in various combinations with or without antivenom and intravenous fluids in the treatment of animals with snake bite, but their role in reducing the severity of envenomations was not assessed.
Clinical implications Antivenom significantly improves the chances of survival of domestic animals bitten by snakes.     

Snake bite: pit vipers

Pit vipers are the largest group of venomous snakes in the United States and are involved in an estimated 150,000 bites annually of dogs and cats. The severity of any pit viper bite is related to the volume and toxicity of the venom injected as well as the location of the bite, which may influence the rate of venom uptake. The toxicity of rattlesnake venom varies widely. It is possible for pit vipers' venom to be strictly neurotoxic with virtually no local signs of envenomation. Venom consists of 90% water and has a minimum of 10 enzymes and 3 to 12 nonenzymatic proteins and peptides in any individual snake. The onset of clinical signs after envenomation may be delayed for several hours. The presence of fang marks does not indicate that envenomation has occurred, only that a bite has taken place. Systemic clinical manifestations encompass a wide variety of problems including pain, weakness, dizziness, nausea, severe hypotension, and thrombocytopenia. The victim's clotting abnormalities largely depend upon the species of snake involved. Venom induced thrombocytopenia occurs in approximately 30% of envenomations. Many first aid measures have been advocated for pit viper bite victims, none has been shown to prevent morbidity or mortality. Current recommendations for first aid in the field are to keep the victim calm, keep the bite site below heart level if possible, and transport the victim to a veterinary medical facility for primary medical intervention. The patient should be hospitalized and monitored closely for a minimum of 8 hours for the onset of signs of envenomation. The only proven specific therapy against pit viper envenomation is the administration of antivenin. The dosage of antivenin needed is calculated relative to the amount of venom injected, the body mass of the victim, and the bite site. The average dosage in dogs and cats is 1 to 2 vials of antivenin.     

Snake envenomation in dogs in New South Wales

OBJECTIVE: To obtain baseline data on the prevalence of elapid snake envenomation in dogs presented to veterinary practices in New South Wales and to assess attitudes of veterinarians to this clinical entity. PROCEDURE: A mailed questionnaire, sent to all veterinary clinics within New South Wales, was utilised to collect epidemiological information regarding elapid snake envenomation in dogs. RESULTS: A response rate of 68% was obtained and a yearly prevalence of snake envenomation in dogs across New South Wales veterinary clinics was estimated as 0.31%. The most common species reported to be responsible for envenomation within NSW was the Red Bellied Black snake (Pseudechis porphyriacus) followed by the Brown snake (Pseudonaja textilis) and then Tiger snake (Notechis scutatus). The reported envenomation syndromes caused by these common snake species were perceived to be similar for Brown and Tiger snakes but differed for Red Bellied Black snakes. Diagnosis of snake envenomation was based predominantly on the recognition of clinical signs. Specific diagnostic tests, such as venom detection kits, were used infrequently. The most common treatment was reported to be a combination of intravenous fluid therapy and antivenom, and monitoring of response to this treatment was usually through assessment of clinical signs. Survival after antivenom administration was reported to be highest for Red Bellied Black snake species. Survival was perceived to be associated with time between envenomation and presentation to the veterinary clinic and with antivenom administration. CONCLUSIONS: Current attitudes and perceptions of veterinarians have been defined. Diagnosis of species-specific snake envenomation is shown to be made on the basis of clinical signs which are, however, reported as similar for each species. Clearer definition of these envenomation syndromes and identification of accessible diagnostic testing procedures are needed.     

Retrospective study of snake envenomation in 155 dogs from the Onderstepoort area of South Africa

A retrospective study was undertaken to evaluate the incidence, signalment, haematological and biochemical changes, therapy, and outcome of dogs presented to the Outpatients section of the Onderstepoort Veterinary Academic Hospital for confirmed snake envenomation. Three hundred and seventy-six records of dogs presented for snake envenomation from 1998 to 2002 were reviewed and 155 were selected on the basis of there being a positively identified snake. The 2 most commonly encountered snake envenomations in dogs were puff-adders (Bitis arietans) and snouted cobras (Naja annulifera annulifera). The majority of cases (56%) occurred in the autumn (March to May), with most being bitten by puff-adders. Dogs were 3 to 168 months old with a median of 36 months. No sex predilection was identified. Ten per cent of cases died because of the snake envenomation. Fifty-seven per cent and 43% of snakebites were puff-adders and cobras, respectively. There was no difference in mortality between the 2 groups of snakes. Of the cobras 60% were the snouted cobra, 14% Mozambique spitting cobra, and 24% rhinkals. Swelling in the area of the bite, usually the face and forequarters, was the primary clinical abnormality. Significant haematological findings were leukocytosis (median 17.3 x 10(9)/l; range 0.4-44), neutrophilia (median 13.6 x 10(9)/l; range 0.3-39.9), band neutrophilia (median 0.4 x 10(9)/l; range 0-5.32), and thrombocytopaenia (median 124 x 10(9)/l; range 3-555). Dogs envenomated by a puff-adder and Mozambique spitting cobra had a greater degree of thrombocytopaenia: median of 68 and 66, respectively, versus 243 for the cobra group. The most commonly used treatments were intravenous fluids, antibiotics and glucocorticoids. Thirty-eight dogs were treated with polyvalent antiserum: 9 for puff-adder envenomation and 29 for cobra envenomation. Only 2 of the dogs that received antisera died, both of them of cobra envenomation. The study concluded that snake envenomation in dogs is associated with high morbidity but moderate mortality rate and that the most significant haematological abnormality is thrombocytopaenia.     

Coral Snake (Micrurus Fulvius Fulvius) Envenomation In Five Dogs: Present And Earlier Findings

The purpose of this study is to report on five cases of coral snake envenomation in the dog to substantiate earlier findings in four dogs reported previously, and to describe any additional clinical features that have not yet been noted. The combined results from both studies allow for a more accurate projection of the frequency of certain clinical signs. Both groups showed signs of lethargy, lower motor neuron weakness (8 of 9 dogs) and varying hematologic changes with hemolysis and hemoglobinuria occurring most commonly (7 of 9 dogs). Cardiac dysrhythmias were recorded infrequently (2 of 9 dogs). Not reported previously was the presence of a subtle bite wound located on the upper or lower lip of three dogs in the present series. An unexpected finding in this second series was the occurrence of an anaphylactoid reaction in one dog presumably attributed to the antivenin. Close examination of the lip might reveal the site of envenomation (as found in 4 of 9 dogs from both studies). Treatment with coral snake antivenin should be given as early as possible and followed by close observation for signs of anaphylaxis. The results of this study substantiate earlier findings and provide for a larger data base for further reference.     

Myotoxicity and nephrotoxicity of common tiger snake (Notechis scutatus) venom in the dog

SUMMARY The myotoxicity and neurotoxicity of common tiger snake (Notechis scutatus) venom are major factors in the pathogenesis of envenomation in the dog. Histological examination of the tissues of experimentally envenomed dogs has demonstrated the importance of muscle damage in affecting the clinical syndrome of tiger snake envenomation. Within one hour of injection of the venom into dogs, there was selective involvement of some muscles. Cardiac and smooth muscles were not significantly affected. The severity of myofibre damage was influenced by the amount of venom injected. Immobilisation under general anaesthesia resulted in significant protection against the myotoxic effects of high doses of venom. Lesions in the kidneys of experimentally envenomed dogs were acute tubular necrosis and the variable presence of a small amount of proteinaceous material in tubules. These lesions, which were similar to those in cases of natural snake bite, were indicative of a direct nephrotoxic effect, which could be complicated by the effects of myoglobinuria. These findings emphasise the need for supportive treatment aimed at maintenance of renal function in the treatment of dogs suffering from tiger snake envenomation.     

Observations on blood coagulation after snakebite in dogs and cats

Blood samples from 13 cases of snakebite, 6 in dogs and 7 in cats, were tested for activated partial thromboplastin time (APTT), prothrombin time (PT) and fibrin/fibrinogen degradation products (FDP). Four cases were tested for fibrinogen concentration. Based on the results of a commercially available ELISA test, 9 cases were caused by tiger snakes (Notechis scutatus) and 1 case by a brown snake (Pseudonaja textilis). Three other cases had clinical signs and increased creatine phosphokinase values which suggested tiger snake envenomation. Although the period post-envenomation varied, results indicated a marked prolongation of the APTT and PT in 5 of 6 dogs. Three of these 5 dogs also had increased FDP values and 3 (of 3 examined) were hypofibrinogenaemic. Clinical manifestations of this coagulopathy were: haematoma formation after venepuncture (3 cases), gingival petechiae (1 case) and hyphaema (1 case). In contrast, there was minimal or no prolongation of the APTT and PT values, and no increase in FDP, in all 7 cats. Furthermore, no cat exhibited clinical signs of a coagulopathy.     

Prospective determination of the specificity of a commercial snake venom detection kit in urine samples from dogs and cats

Objective To determine the specificity of a snake venom detection kit in urine samples from dogs and cats presenting to a referral centre for diseases unrelated to snake envenomation. Design Urine was collected from 50 dog and 25 cats presented for investigation and treatment of diseases unrelated to snake envenomation. Urine was collected as a voided sample, by cystocentesis or by catheterisation, and routine urinanalysis was performed. Snake venom testing was performed within 2 h of collection using a commercially available snake venom detection kit, which was observed continuously during the 10-min colour reaction phase for evidence of a visible colour indicating a positive test. Results No false-positive reactions occurred in any sample analysed. Conclusion The snake venom detection kit appears to have 100% specificity for using urine as a test sample.     

The diagnosis and management of snakebite in dogs--a southern African perspective

Cases of snakebite envenomation are frequently presented to veterinary practitioners in southern Africa. Despite this, no published guidelines exist on how this medical emergency should be managed. Southern African snake venoms can be classified into 3 main types based on the main mechanism of venom action and clinical presentation. A polyvalent antivenom is manufactured in South Africa and contains antibodies against the most important southern African snake venoms. The cytotoxic venoms are represented mainly by the puff-adder (Bitis arietans), Mozambique spitting cobra (Naja mossabica), black-necked spitting cobra (Naja nigricollis) (in the Western Cape and Namibia) and the stiletto snake (Atractaspis bibronii). These venoms may cause dramatic local swelling, high morbidity and low mortality and infrequently require the use of antivenom for survival (the only cytotoxic venoms used to prepare the antivenom are the puff-adder and Mozambique spitting cobra). The neurotoxic venoms (represented chiefly by the non-spitting cobras and mambas) cause high mortality due to rapid onset of paresis and require antivenom and mechanical ventilatory support which is life-saving. The boomslang (Dispholidus typus) and the vine snake (coagulopathic venom) rarely bite humans but dogs may be bitten more frequently. These venoms cause a consumption coagulopathy and successful treatment of boomslang bites requires the use of snake species-specific monovalent antivenom. There is no antivenom available for treating vine snake (Thelotornis capensis), berg adder (Bitis atropos), night adder (Causus spp.), stiletto snake and other lesser adder bites. There are some important differences between the way snakebites are managed in humans and dogs.     

Evaluation of risk factors for bite wounds inflicted on caregivers by dogs and cats in a veterinary teaching hospital

OBJECTIVE: To identify factors associated with increased risk of being bitten by a dog or cat in a veterinary teaching hospital. DESIGN: Unmatched case-control study. STUDY POPULATION: 207 animal caregivers. PROCEDURE: Case subjects (n = 75) were any caregiver that reported being bitten by a dog or cat. Control subjects (n = 132) were randomly selected from a list of all caregivers interacting with dogs or cats. Information on the characteristics of the caregivers, characteristics of the dogs and cats, and the nature of the interaction between the dog or cat and the caregiver was obtained by use of self-administered questionnaires. RESULTS: Caregivers were more likely to be bitten by dogs or cats that had warning signs on their cages indicating the potential to bite or that were considered difficult to handle. Caregivers interacting with cats or with older dogs and cats were more likely to be bitten. Only 37 to 55% of dogs and cats that had characteristics traditionally associated with biting or were considered likely to bite were muzzled. CONCLUSIONS AND CLINICAL RELEVANCE: Muzzling dogs and cats should be considered more frequently. Dogs and cats considered to have the propensity to bite frequently do bite, and precautions, such as muzzling, should be taken if the medical condition or conformation of the dog or cat is amenable to this type of restraint.     

Ileocolic junction resection in dogs and cats: 18 cases

There is limited veterinary literature about dogs or cats with ileocolic junction resection and its long-term follow-up. To evaluate the long-term outcome in a cohort of dogs and cats that underwent resection of the ileocolic junction without extensive (≥50%) small or large bowel resection. Medical records of dogs and cats that had the ileocolic junction resected were reviewed. Follow-up information was obtained either by telephone interview or e-mail correspondence with the referring veterinary surgeons. Nine dogs and nine cats were included. The most common cause of ileocolic junction resection was intussusception in dogs (5/9) and neoplasia in cats (6/9). Two dogs with ileocolic junction lymphoma died postoperatively. Only 2 of 15 animals, for which long-term follow-up information was available, had soft stools. However, three dogs with suspected chronic enteropathy required long-term treatment with hypoallergenic diets alone or in combination with medical treatment to avoid the development of diarrhoea. Four of 6 cats with ileocolic junction neoplasia were euthanised as a consequence of progressive disease. Dogs and cats undergoing ileocolic junction resection and surviving the perioperative period may have a good long-term outcome with mild or absent clinical signs but long-term medical management may be required.     

Clinical findings associated with prairie rattlesnake bites in dogs: 100 cases (1989-1998)

OBJECTIVE: To identify clinically relevant variables and treatments for dogs bitten by prairie rattlesnakes (Crotalus viridis viridis). DESIGN: Retrospective study. ANIMALS: 100 client-owned dogs. PROCEDURE: Records of dogs evaluated for rattlesnake envenomation from 1989 to 1998 were reviewed. Analysis was performed to test for significant associations among clinical variables or treatments and cell counts, costs, and duration of hospitalization. RESULTS: Most prairie rattlesnake bites occurred between May and September. Dogs were 3 months to 12 years old (median, 3.7 years); most were bitten on the head in the late afternoon. There was no sex predilection. Median time to evaluation was 1 hour (range, 15 minutes to 13 hours). Swelling in the area of the bite was the primary physical abnormality. Principal initial laboratory findings were echinocytosis, thrombocytopenia, leukocytosis, and prolonged activated clotting time. Ninety-four dogs were hospitalized; 48 were discharged the following day. Antimicrobials and crystalloid fluids, glucocorticoids, antihistamines, and antivenin administered i.v. were the most commonly used treatments. One dog died, and small dogs were hospitalized longer than large dogs. Antivenin administration was not significantly associated with duration of hospitalization but was associated with higher platelet counts after treatment and higher total hospital costs. CONCLUSIONS AND CLINICAL RELEVANCE: Prairie rattlesnake envenomation in dogs is associated with high morbidity rate but low mortality rate. The efficacy of administration of antivenin for dogs with bites from this snake species is questionable.     

A survey of animal bites on humans in Bursa,Turkey

Animal bites are a major public health problem. The aim of this study was to conduct a survey of animal bites in Bursa, Turkey. Patients who sought medical care for animal bites over an 18-month period were included in our study (n = 1,715). Data were obtained from the registry of the Bursa State Hospital; 71.84% of the patients were men and 28.16% were women. Bites were most frequent among patients who were >18 years of age (comprising 60.83% of all bites). The anatomical site of the bite was recorded in all 1,715 cases, and 1,778 bite locations on the body were reported. The upper extremities were the most frequent sites of animal bites (53.83%), followed by the lower extremities (38.03%). Bites were most frequently inflicted by dogs (68.04%), followed by cats (28.45%), mice (2.56%), and other animals (hamsters, donkeys, horses, foxes, and rabbits together comprised 0.95% of the bites). As a result, bite incidents were mostly associated with males aged >18 years and occurred in the upper extremities. This study showed that dog bites constitute a major animal bite problem in Bursa, Turkey.     

The occurrence of Clostridium difficile in fecal samples of dogs and cats

Fecal samples of 150 dogs and 175 cats originating from different veterinary practices were investigated for assessing the occurrence of Clostridium (Cl.) difficile by using a selective medium for cultural isolation. From dogs without enteric symptoms 7 (9.3%) of 75 samples were positive for Cl. difficile, with 2 strains being cytotoxic for bovine embryonic lung fibroblast cells, which could be neutralized by Cl. difficile-antitoxin. In samples of 75 dogs with enteric symptoms Cl. difficile could be isolated in 2 cases (2.7%). In cats 9 (9%) of 100 fecal samples deriving from animals without enteric symptoms contained Cl. difficile, while in 75 cats with enteric symptoms, the isolation rate was 6.7% (5 strains). Of either group only 1 Cl. difficile-strain showed cytotoxicity for tissue culture. The results of this study allow to conclude, that in contrast to the significance for man Cl. difficile is neither for dogs nor for cats an important enteric agent. However these pets can harbour and shed strains of Cl. difficile, even cytotoxigenic ones, in faeces. In view of these findings the possibility of occasional human infections by household dogs or cats needs attention and further investigation.     

Megaoesophagus in adult dogs secondary to Australian tiger snake envenomation

Four cases of megaoesophagus secondary to tiger snake envenomation are reported. History in all cases suggested megaoesophagus was not present prior to snake envenomation. Diagnosis of megaoesophagus was confirmed by thoracic radiography in all cases. One dog died of respiratory failure. The remaining three dogs recovered, with gradual resolution of clinical signs associated with megaoesophagus.     

A randomized multicenter trial of Crotalidae polyvalent immune Fab antivenom for the treatment of rattlesnake envenomation in dogs

Objective – To determine clinical efficacy of the Crotalidae polyvalent immune F_ab (ovine) antivenom (OPCA) against progressive crotalid envenomation in the dog as reflected in stabilization or improvement of snakebite severity scores (SSS). Additionally, due to the potential decreased half‐life of the F_ab antibodies in dogs we compared SSS between dogs receiving 2 different dosing regimes. Design – Prospective, clinical trial. Setting – Five veterinary emergency and critical care facilities. Animals – One hundred and fifteen client‐owned Crotalid (rattlesnake) snake bitten dogs in whom worsening of the envenomation syndrome was observed before OPCA treatment. Interventions – In a multicenter randomized clinical trial a single dose (1 vial) of OPCA alone was compared with 2 doses (1/2 vial each) administered 6 hours apart. Standard supportive care was provided in all cases. Measurements and Main Results – Data were available for 115 patients, 9 of which were fatalities. All patients' clinical condition was documented with a standardized SSS system accounting for each major body system. Each fatality received maximum severity scores of 20. The mean severity score of the 115 patients decreased from 4.19 to 3.29 points and there was no difference between the 2 treatment groups. The mean severity score of the 107 patients without fatalities decreased from 4.16 to 2.15. Antivenin‐related acute reactions occurred in 6 dogs (6%), and no serum sickness occurred within the 95 cases contacted at the 2‐week posttreatment follow‐up. Conclusions – In the first randomized trial in dogs of antivenin in the United States, OPCA effectively stabilized or terminated venom effects. There were no statistical differences detected between treatment groups within the study time frame.     

Prevalence and factors associated with initial and subsequent shockable cardiac arrest rhythms and their association with patient outcomes in dogs and cats undergoing cardiopulmonary resuscitation: A RECOVER registry study

Objective

To report the prevalence of initial shockable cardiac arrest rhythms (I-SHKR), incidence of subsequent shockable cardiac arrest rhythms (S-SHKR), and factors associated with I-SHKRs and S-SHKRs and explore their association with return of spontaneous circulation (ROSC) rates in dogs and cats undergoing CPR.

Design

Multi-institutional prospective case series from 2016 to 2021, retrospectively analyzed.

Setting

Eight university and eight private practice veterinary hospitals.

Animals

A total of 457 dogs and 170 cats with recorded cardiac arrest rhythm and event outcome reported in the Reassessment Campaign on Veterinary Resuscitation CPR registry.

Measurements and Main Results

Logistic regression was used to evaluate association of animal, hospital, and arrest variables with I-SHKRs and S-SHKRs and with patient outcomes. Odds ratios (ORs) were generated, and significance was set at P < 0.05. Of 627 animals included, 28 (4%) had I-SHKRs. Odds for I-SHKRs were significantly higher in animals with a metabolic cause of arrest (OR 7.61) and that received lidocaine (OR 17.50) or amiodarone (OR 21.22) and significantly lower in animals experiencing arrest during daytime hours (OR 0.22), in the ICU (OR 0.27), in the emergency room (OR 0.13), and out of hospital (OR 0.18) and that received epinephrine (OR 0.19). Of 599 initial nonshockable rhythms, 74 (12%) developed S-SHKRs. Odds for S-SHKRs were significantly higher in animals with higher body weight (OR 1.03), hemorrhage (OR 2.85), or intracranial cause of arrest (OR 3.73) and that received epinephrine (OR 11.36) or lidocaine (OR 18.72) and significantly decreased in those arresting in ICU (OR 0.27), emergency room (OR 0.29), and out of hospital (OR 0.38). Overall, 171 (27%) animals achieved ROSC, 81 (13%) achieved sustained ROSC, and 15 (2%) survived. Neither I-SHKRs nor S-SHKRs were significantly associated with ROSC.

Conclusions

I-SHKRs and S-SHKRs occur infrequently in dogs and cats undergoing CPR and are not associated with increased ROSC rates.     

Efficacy of nitenpyram as a systemic flea adulticide in dogs and cats

In a clinical trial involving 123 cats and 88 dogs, the efficacy of tablets containing nitenpyram against natural flea infestations was investigated. The animals were selected from the routine cases of nine veterinary clinics in the UK and 143 were treated with the tablets and 68 control animals were treated with placebo tablets. Each animal was maintained in an individual cage. The time when the first fleas fell off each animal was recorded between 30 minutes and five hours after treatment, and six hours after treatment the numbers of live, moribund or dead fleas on each animal were determined, and the flea survival rate was calculated. The drug's efficacy was assessed by comparing the mean survival rates of fleas on the treated and control animals. Fleas started to fall from the animals 30 minutes after treatment and two hours after treatment some fleas had detached from 81 per cent of the treated animals. After six hours the efficacy of the drug reached 96.7 per cent on dogs and 95.2 per cent on cats, and 85.9 per cent of the fleas were found off the treated animals, compared with 1.8 per cent in the controls. No adverse drug reactions were recorded during the trial.