Clinico-epidemiology and management of hump-nosed pit viper (Hypnale spp.) bites in dogs.

Human envenoming from the bite of the abundant hump-nosed pit viper (Hypnale spp.) (HNPV) is a frequent occurrence with victims experiencing unpleasant and sometimes life-threatening consequences. Further, clinico-pathology, treatment and management measures in HNPV envenomed dogs are under recognized. Prospective investigations were performed to assess the clinico-pathology and management options for HNPV envenomed dogs brought to the University of Peradeniya's Veterinary Teaching Hospital from January, 2012 to March 2018. We recorded the local and systemic manifestations, hematological and urinary abnormalities of 78 dogs in which HNPV bite had been witnessed by the owner. Mild swelling, extensive swelling, hemorrhagic blistering and hemorrhagic bullae at the site of bite were observed in 59%, 31%, 6% and 4% of the dogs, respectively. Some dogs were subjected to surgical excision of necrotized tissue including limb amputation. We observed the following systemic clinical effects in envenomed dogs: neurotoxicity (13%), acute kidney injury (AKI) (14%) and coagulopathy (16%). All dogs showed leukocytosis with mean white blood cell count of 25.25 × 103/µL. Mild anemia and thrombocytopenia were detected in 29% of the dogs. There was a significant correlation between extent of local tissue injuries with length of hospitalization (LH). The mean time of coagulopathy observed was 21.3 h (IQR: 8-48 h). In coagulopathic dogs, there was a strong correlation between LH and extent of local tissue injury (rs = 0.7751, P < 0.0001); LH and whole blood clotting time(CT) (rs = 1.0, P < 0.0001); PT and aPTT (rs = 0.4712, P < 0.001). LH was significantly correlated with the development of AKI (p = 0.0013). Lack of specific antivenom (AVS) for HNPV envenoming provided an opportunity to study the remaining treatment options. Therefore, the study allowed the identification of local and systemic effects, hematological abnormalities, possible supportive treatments and drawbacks of management measures for envenomed dogs.

Snakebite in domestic animals: First global scoping review.

Snakebite is a Neglected Tropical Disease estimated to cause more than 100,000 human deaths and disable more than 400,000 victims each year. It primarily affects poor agricultural workers, farmers, and cattle herders living in rural areas of developing countries. It is thus an occupational disease. However, the impact of snakebite on these rural communities could be even higher if a One Health approach is taken to consider the direct impact on domestic animals and indirect impact on the livelihood of affected communities. To explore this hypothesis we developed the first scoping review to identify and characterize the global literature on snakebite in domestic animals. Three bibliographic databases (PubMed, Web of Science and Agricola) were searched using terms related to snake, snakebite and domestic animals for publications up to December 31st, 2016. Two independent reviewers screened publications applying inclusion/exclusion criteria to select relevant material. Relevant information was then extracted from the selected literature. The global literature on snakebite in domestic animals (n = 143 observational studies, reviews and letters) mainly represented North America, Europe and Australia (69%) with less information from Central and South America, Asia and Africa (31%). Observational studies (n = 119) mostly concerned pets (78%) and to a lesser extent livestock (22%). Thirty-four snake species were reported as responsible for bites in domestic animals. WHO's Medically Important Venomous Snakes were more frequently involved. The social-ecological determinants of snakebite were poorly documented but the reviewed literature suggested a strong seasonality and a diversity of habitat. Snakebite in animals caused neurotoxic, cytotoxic and hemotoxic envenomation syndromes similar to humans and death. Half of publications on envenomed livestock reported a fatality rate above 47%. There was no literature on the indirect impact of snakebite on livelihood caused by animal morbidity and mortality. The results of this scoping review suggest a high and under-reported burden in terms of mortality in animals and a potential economic impact of snakebite in terms of losses in livelihood of affected communities. However, major knowledge gaps with respect to impact of snakebite on livestock and livelihood were identified. Filling these gaps is necessary for a full understanding of the impact of snakebite and to raise scientific, political and public awareness on this neglected issue.

Retrospective evaluation of the effect of antivenom administration on hospitalization duration and treatment cost for dogs envenomated by Crotalus viridis: 113 dogs (2004-2012).

OBJECTIVE: To compare the effect of antivenom administration on mortality, hospitalization duration, and cost of hospitalization for dogs envenomated by Crotalus viridis. DESIGN: Retrospective study (January 2004-December 2012). SETTING: Private veterinary emergency and referral center. ANIMALS: One hundred thirteen dogs with confirmed C. viridis envenomation. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Dogs were divided into groups treated with either supportive care only (group 1) or supportive care plus antivenin crotalidae polyvalent (group 2). A modified snakebite severity score was used to compare patients from group 1 and group 2. Patients in group 2 received one 10 mL vial of antivenin crotalidae polyvalent over 4-6 hours. The mortality rate was 1.8% (2/113).  Group 1 had a median duration of hospitalization of 20 hours (range, 8-50 hours), while group 2 had a median duration of hospitalization of 24 hours (range, 1.5-74 hours). Group 1 had a median cost of hospitalization of 1050.00 USD (range, 423.52-2266.09 USD) while group 2 had a median cost of hospitalization of 2002.19 USD (range, 1139.91-6908.01 USD). Both the duration of hospitalization (P < 0.01) and the cost of hospitalization (P < 0.01) were significantly greater in the group of dogs receiving antivenom. CONCLUSIONS: Both the cost and the duration of hospitalization were significantly greater in the group of dogs that received antivenom. The difference in cost between the groups was approximately the cost of the antivenom vial and administration. Amongst the parameters evaluated, no significant benefit was associated with antivenom administered to dogs envenomated by C. viridis.

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.