Epidemiology of snakebite in a central region of Brazil

Study of defensive behavior of a venomous snake as a new approach to understand snakebite

Snakebites affect millions of people worldwide. The majority of research and management about snakebites focus on venom and antivenom, with less attention given to snake ecology. The fundamental factor in snakebites is the snakes' defensive biting behavior. Herein we examine the effects of environmental variables (temperature, time of day, and human stimulus) and biological variables (sex and body size) on the biting behavior of a medically significant pit viper species in Brazil, Bothrops jararaca (Viperidae), and associate it with the epidemiology of snakebites. Through experimental simulations of encounters between humans and snakes, we obtained behavioral models applicable to epidemiological situations in the State of São Paulo, Brazil. We found a significant overlap between behavioral, morphological, environmental, and epidemiological data. Variables that increase snakebites in epidemiological data also enhance the tendency of snakes to bite defensively, resulting in snakebites. We propose that snakebite incidents are influenced by environmental and morphological factors, affecting the behavior of snakes and the proportion of incidents. Thus, investigating behavior of snakes related to snakebite incidents is a valuable tool for a better understanding of the epidemiology of these events, helping the prediction and, thus, prevention of snakebites.

Surgical Management of Patients with Snakebite-Related Musculoskeletal Complication-A Single Institution Experience in Cambodia

BACKGROUND

Snakebite-related injury is a serious public health issue. In Cambodia, it is estimated that up to 21,500 cases of envenoming occurs from snakebites annually. Musculoskeletal disability is a major long-term complication associated with the injury. In this study, we aim to describe surgical management and rehabilitation in snakebite-related musculoskeletal injuries at Children's Surgical Centre, Phnom Penh, Cambodia.

METHODS

We conducted a retrospective case series analysis of patients with snakebite-related injury who were treated between January 1, 2002 and December 31, 2018. Surgical patients were divided into the early and late presenting groups (= < one year vs. > one year, respectively) based on their time interval from snake bite to time of presentation.

RESULTS

There were 88 patients who presented with snakebite-related musculoskeletal injury during the cohort study period. Majority of them were male (n = 62, 71%) and had a median age of 24 years old (IQR 17-44). The injuries were all in the upper and lower limbs though lower limb injury was more common in female patients (81% vs. 48%, Fisher's test p = 0.005). The median time interval from snakebite to time of treatment was 3 years (IQR 3 months-11 years). In this study, 65 patients received surgical interventions. An ulcerated wound was the most common symptom among the early presenting group (78% vs. 24%), while scar contracture was most common among the late group (76% vs. 22%) (Fisher's test p < 0.0001). For management, surgical debridement was the most common primary intervention for the early group (52% vs. 19%), and contracture release was the most common for patients in the late group (62% vs. 15%) (Fisher's test p = 0.0004). Overall, the postoperative complication rate was highest in the late presenting group (34% vs. 3%, Fisher's test p = 0.005).

CONCLUSION

More than half of the patients presented with musculoskeletal injury require surgical correction. Our study demonstrated that scar contracture is the most common complaint among the late presenting group and is associated with high postoperative complication rate.

From birth to adulthood: An analysis of the Brazilian lancehead (Bothrops moojeni) venom at different life stages

The Brazilian lancehead (Bothrops moojeni) has a wide distribution in Brazil and represents a serious public health hazard. Previous works reported that the symptoms of snakebites caused by B. moojeni juveniles’ bites were mainly related to coagulation, while those caused by adults’ bites had a more prominent local damage. In this work, we analyzed the venoms of B. moojeni at different life stages to better understand the ontogeny shift in this species. Snakes were grouped by age and sex, and venom pools were formed accordingly. Compositional analyses by one-dimensional electrophoresis (1-DE), chromatography, and mass spectrometry revealed that ontogenetic changes might be mostly related to phospholipase A₂ (PLA₂) and metalloproteases. Regarding the venoms functional aspect, proteolytic, L-amino acid oxidase, PLA₂, and coagulant in vitro activities were assayed, but only the first and the last ones showed age-related changes, with the venom of snakes up to 1 year-old displaying lower proteolytic and higher coagulant activities, while those from 2 years-old onward presented the opposite relation. The venoms of 3 years-old snakes were exceptions to the compositional and functional pattern of adults as both venoms presented profiles similar to neonates. Sex-related differences were observed in specific groups and were not age-related. In vivo experiments (median lethal dose and hemorrhagic activity) were statistically similar between neonates and adults, however we verified that the adult venom killed mice faster comparing to the neonates. All venoms were mostly recognized by the antibothropic serum and displayed similar profiles to 1-DE in western blotting. In conclusion, the Brazilian lancehead venom showed ontogenetic shift in its composition and activities. Furthermore, this change occurred in snakes from 1 to 2 years-old, and interestingly the venom pools from 3 years-old snakes had particular characteristics, which highlights the importance of comprehensive studies to better understand venom variability.

New insights into snakebite epidemiology in Costa Rica: A retrospective evaluation of medical records

Continuous monitoring of the snakebite envenoming allows elucidating factors that affect its incidence at spatial and temporal scales, and is a great tool to evaluate the proper management of snakebite in health centers. To determine if there have been changes over time in snakebite epidemiology in Costa Rica, we conducted a retrospective study using medical records from six hospitals for the years 2012-2013. A total of 475 snakebite patients were treated at the selected hospital during this period. Most bites occurred during the rainy season and primarily affected young men, mainly farm workers and schoolchildren. About 55% of bites occur in peri-domiciliary environments, although its prevalence varies geographically. Bothrops asper generates the vast majority of envenoming in the country, which is why the main local symptoms registered are edema, pain, and bleeding disorders. The time elapsed until treatment did not explain the degree of severity at admission. However, complications were observed more frequently in patients who took longer to receive treatment. The primary complications were bacterial infections, whereas kidney failure and compartment syndrome documented at very low frequencies. Only one death was recorded, reflecting the low fatality rate exhibited in the country. Hospital treatment included the rapid administration of antivenom and complementary treatment of antibiotics, analgesics, and antihistamines. The application of the latter as prophylactic does not seem to prevent the appearance of mild early adverse reactions, registered in 22.5% of the cases. Morbidity and mortality rates from snakebite have continued to decrease in the country, as a result of the efforts that Costa Rica has made to improve its public health system. Among those efforts, the creation of primary care centers (EBAIS) has reduced the time to treatment in many regions of the country. The Costa Rican experience of using antivenom in primary health care centers and maintaining good medical records could be considered for application in other countries where snakebite is a major health problem.

Time to treatment and severity of snake envenoming in Brazil

Objective

To analyze the relationship between time to treatment and severity of snakebite envenomation in Brazil.

Methods

This case-series retrospective study analyzed 144 251 snakebite cases in Brazil between 2007 and 2015, as reported to the Brazilian Notifiable Diseases Information System. The main dependent variable was snakebite envenomation severity (mild/moderate/severe). The main predictor was time to treatment (early (< 6 hours) vs. delayed (≥ 6 hours)). Covariables were snake type (Bothrops/Crotalus/Micrurus/Lachesis), patient's age and sex, bite site, and treatment at a specialized care center (center/noncenter). Polytomous logistic regression techniques were used to control the covariates and assess confounding and effect modification.

Results

The time to treatment variable was strongly associated with the severity of snakebite envenomation. Snake type and treatment at specialized care center modified the main association effect. The association between delayed time to treatment and envenomation severity was consistently stronger among patients treated at specialized care centers than among those who were not treated at such centers. Odds ratios tended to increase significantly from moderate to severe envenomation for cases within the subgroups “Center + Bothrops” (1.37 to 2.05), “No center + Bothrops” (1.25 to 1.47), “Center + Crotalus” (1.35 to 3.03), “No center + Crotalus” (0.97 to 2.72), and “Center + Lachesis” (1.22 to 1.89).

Discussion

This study confirmed the classical hypothesis that the time between snakebite and initiation of medical care is associated with severity of snakebite envenomation. It is therefore necessary to provide snakebite victims early access to specialized medical care, particularly to antivenom therapy.

Assessment of the anti-snakebite properties of extracts of Aniba fragrans Ducke (Lauraceae) used in folk medicine as complementary treatment in cases of envenomation by Bothrops atrox

ETHNOPHARMACOLOGICAL RELEVANCE

Extracts of leaves and bark of Aniba fragrans are used as tea (decoction) to treat snakebites in communities in the Brazilian Amazon. The aqueous extract of the leaves of A. fragrans has been proven to be effective against Bothrops venom, but only when pre-incubated with the venom. This study sought to assess the potential of different types of extract of this species to inhibit the biological activities of Bothrops atrox venom (BaV) when used the same way as in folk medicine. The main classes of secondary metabolites and the concentrations of phenolics in the extracts were also determined.

MATERIALS AND METHODS

Four types of extract of A. fragrans were prepared: aqueous extract of the leaf (AEL), aqueous extract of the bark (AEB), hydroalcoholic leaf extract (HLE) and extract of the residue from hydrodistillation of the leaf (ERHL). The phytochemical profiles of the aqueous extracts were determined using thin layer chromatography (TLC), and the concentrations of phenolics were measured by colorimetric assays. To investigate the potential of the extracts to inhibit the biological activities of BaV, in vitro tests for antiphospholipase and antifibrinolytic activities were performed. In vivo tests for antihemorrhagic and antidefibrinating activities were also carried out, as well as antimicrobial tests for activity against the main bacteria found in the oral cavity of snakes. Interaction between the extracts and the proteins in BaV was assessed by electrophoresis (SDS-PAGE) and Western blot (WB). The cytotoxicity of the extracts was assessed in a strain of MRC-5 human fibroblasts.

RESULTS

Terpenoids, flavonoids and condensed and hydrolysable tannins were detected in all the extracts. Metabolites such as coumarins, fatty acids and alkaloids were present in some extracts but not in others, indicating different phytochemical profiles. Phenolics content varied between extracts, and there were more tannins in AEB and HLE. In the in vitro tests, the extracts inhibited the phospholipase and fibrinolytic activities of BaV in the two ratios of venom to extract used. HLE exhibited effective antimicrobial action as it inhibited growth of 11 of the 15 bacteria investigated, including Morganella morganii, the main bacteria described in the oral cavity of snakes. The extracts failed to inhibit the defibrinating activity of BaV, and only the Bothrops antivenom had a significant effect (96.1%) on this activity. BaV-induced hemorrhage was completely inhibited by AEL and AEB when the pre-incubation (venom:extract) protocol was used. When administered orally, as in folk medicine, both AEB and AEL produced significant inhibition of hemorrhagic activity (maximum inhibition 46.5% and 39.2%, respectively). SDS-PAGE and WB of the extracts pre-incubated with BaV showed that the main proteins in the venom had been precipitated by the extracts. None of the four extracts showed cytotoxic effects in the tests carried out with a human fibroblast cell line.

CONCLUSION

In addition to being effective in reducing hemorrhage when administered orally, the extracts displayed a high antimicrobial potential against microorganisms involved in secondary infections at the site of the snakebite. Once the extracts have been tested in accordance with the appropriate regulations, this species could potentially be used to produce a phytomedicine for complementary treatment of the secondary infections due to bacteria that aggravate the local signs and symptoms after snakebite envenomation.

Effects of Bothrops alternatus venom in zebrafish: a histopathological study

Zebrafish is an excellent model organism for studying tissue alterations caused by Bothrops alternatus venom (BAV) and for screening new anti-venom drugs. To study tissue alterations following exposure to BAV and the roles that glucocorticoids play in these tissue reactions, zebrafish were randomly divided into five groups: the free injection control group (FIC), the phosphate-buffered saline injection control group (PIC), the venom injected group (VI), the group treated with dexamethasone 1 h before venom injection (D1hBVI) and the group treated with dexamethasone 1 h after venom injection (D1hAVI). The concentration of BAV injected was 0.13 mg/mL and each fish received an injection of 20 μL. Body weight measurements and histopathological characteristics of the gills, kidneys, liver, and intestine were determined. Histopathological analyses showed necrosis, inflammation and weight gain in animals that received BAV. The histological alteration indices of the gills, liver, kidneys, and intestines were statistically higher in the animal groups treated with BAV. These alteration indices were lower in the D1hBVI and D1hAVI groups compared to the group treated with BAV alone. The D1hBVI group is presented with minor alterations. A significant difference in the histological alterations index was observed in the intestinal tissue of the FIC group compared to the PIC group. Cumulatively, zebrafish may serve as a useful biomarker for alterations induced by BAV. Interestingly, dexamethasone reduced the damage caused by BAV in the organs studied, which suggests that zebrafish might be useful for screening new drugs that can mitigate tissue damage caused by snakebites.

The role of TLR2 in the acute inflammatory response induced by Bothrops atrox snake venom

Envenomation by snakes of the species Bothrops atrox induces local and systemic effects. Local effects include drastic tissue damage and a marked inflammatory response as a result of the synthesis and release of a variety of protein and lipid mediators. Toll-like receptor (TLR) signaling pathways can play an important role in this response, leading to synthesis of these inflammatory mediators. This study investigated the influence of TLR2 on the acute inflammatory response induced by Bothrops atrox venom. Wild-type C57BL/6 mice (WT) and TLR2 gene knockout mice (TLR2(-/-)) were injected with Bothrops atrox venom (BaV), and the following responses to the venom were assessed in peritoneal exudate: leukocyte accumulation; release of mediators, including CCL-2, IL-10, IL-1β, IL-6 and LTB4; protein expression of COX-1 and COX-2; and quantification of their products PGE2 and TXA2. After injection with BaV, the TLR2(-/-) mice (TLR2(-/-)BaV) had higher levels of IL-6 and CCL-2 than WT animals kept under the same conditions (WTBaV), together with an accumulation of polymorphonuclear leukocytes (PMNs), inhibition of IL-1β and LTB4 and reduced mononuclear leukocyte influx. However, no significant differences in COX-2 protein expression or PGE2, TXA2 and IL-10 production between the TLR2(-/-)BaV and WTBav animals were observed. Together, these results indicate that the signaling pathway activated by TLR2 acts by modulating the induced inflammatory response to BaV through the direct action of venom-associated molecular patterns (VAMPs) or indirectly by forming damage-associated molecular patterns (DAMPs) and that this may have important therapeutic implications.

Photobiomodulation Protects and Promotes Differentiation of C2C12 Myoblast Cells Exposed to Snake Venom

BACKGROUND

Snakebites is a neglected disease and in Brazil is considered a serious health problem, with the majority of the snakebites caused by the genus Bothrops. Antivenom therapy and other first-aid treatments do not reverse local myonecrose which is the main sequel caused by the envenomation. Several studies have shown the effectiveness of low level laser (LLL) therapy in reducing local myonecrosis induced by Bothropic venoms, however the mechanism involved in this effect is unknown. In this in vitro study, we aimed to analyze the effect of LLL irradiation against cytotoxicity induced by Bothrops jararacussu venom on myoblast C2C12 cells.

METHODOLOGY

C2C12 were utilized as a model target and were incubated with B. jararacussu venom (12.5 μg/mL) and immediately irradiated with LLL at wavelength of red 685 nm or infrared 830 nm with energy density of 2.0, 4.6 and 7.0 J/cm2. Effects of LLL on cellular responses of venom-induced cytotoxicity were examined, including cell viability, measurement of cell damage and intra and extracellular ATP levels, expression of myogenic regulatory factors, as well as cellular differentiation.

RESULTS

In non-irradiated cells, the venom caused a decrease in cell viability and a massive release of LDH and CK levels indicating myonecrosis. Infrared and red laser at all energy densities were able to considerably decrease venom-induced cytotoxicity. Laser irradiation induced myoblasts to differentiate into myotubes and this effect was accompanied by up regulation of MyoD and specially myogenin. Moreover, LLL was able to reduce the extracellular while increased the intracellular ATP content after venom exposure. In addition, no difference in the intensity of cytotoxicity was shown by non-irradiated and irradiated venom.

CONCLUSION

LLL irradiation caused a protective effect on C2C12 cells against the cytotoxicity caused by B. jararacussu venom and promotes differentiation of these cells by up regulation of myogenic factors. A modulatory effect of ATP synthesis may be suggested as a possible mechanism mediating cytoprotection observed under laser irradiation.

Moojenactivase, a novel pro-coagulant PIIId metalloprotease isolated from Bothrops moojeni snake venom, activates coagulation factors II and X and induces tissue factor up-regulation in leukocytes

Coagulopathies following snakebite are triggered by pro-coagulant venom toxins, in which metalloproteases play a major role in envenomation-induced coagulation disorders by acting on coagulation cascade, platelet function and fibrinolysis. Considering this relevance, here we describe the isolation and biochemical characterization of moojenactivase (MooA), a metalloprotease from Bothrops moojeni snake venom, and investigate its involvement in hemostasis in vitro. MooA is a glycoprotein of 85,746.22 Da, member of the PIIId group of snake venom metalloproteases, composed of three linked disulfide-bonded chains: an N-glycosylated heavy chain, and two light chains. The venom protease induced human plasma clotting in vitro by activating on both blood coagulation factors II (prothrombin) and X, which in turn generated α-thrombin and factor Xa, respectively. Additionally, MooA induced expression of tissue factor (TF) on the membrane surface of peripheral blood mononuclear cells (PBMC), which led these cells to adopt pro-coagulant characteristics. MooA was also shown to be involved with production of the inflammatory mediators TNF-α, IL-8 and MCP-1, suggesting an association between MooA pro-inflammatory stimulation of PBMC and TF up-regulation. We also observed aggregation of washed platelets when in presence of MooA; however, the protease had no effect on fibrinolysis. Our findings show that MooA is a novel hemostatically active metalloprotease, which may lead to the development of coagulopathies during B. moojeni envenomation. Moreover, the metalloprotease may contribute to the development of new diagnostic tools and pharmacological approaches applied to hemostatic disorders.

Effect of diterpenes isolated of the marine alga Canistrocarpus cervicornis against some toxic effects of the venom of the bothrops jararaca snake

Snake venoms are composed of a complex mixture of active proteins and peptides which induce a wide range of toxic effects. Envenomation by Bothrops jararaca venom results in hemorrhage, edema, pain, tissue necrosis and hemolysis. In this work, the effect of a mixture of two secodolastane diterpenes (linearol/isolinearol), previously isolated from the Brazilian marine brown alga, Canistrocarpus cervicornis, was evaluated against some of the toxic effects induced by B. jararaca venom. The mixture of diterpenes was dissolved in dimethylsulfoxide and incubated with venom for 30 min at room temperature, and then several in vivo (hemorrhage, edema and lethality) and in vitro (hemolysis, plasma clotting and proteolysis) assays were performed. The diterpenes inhibited hemolysis, proteolysis and hemorrhage, but failed to inhibit clotting and edema induced by B. jararaca venom. Moreover, diterpenes partially protected mice from lethality caused by B. jararaca venom. The search for natural inhibitors of B. jararaca venom in C. cervicornis algae is a relevant subject, since seaweeds are a rich and powerful source of active molecules which are as yet but poorly explored. Our results suggest that these diterpenes have the potential to be used against Bothropic envenomation accidents or to improve traditional treatments for snake bites.

Venomics and antivenomics of Bothrops erythromelas from five geographic populations within the Caatinga ecoregion of northeastern Brazil

The Caatinga lancehead, Bothrops erythromelas, is a medically relevant species, responsible for most of the snakebite accidents in most parts of its distribution range in northeastern Brazil. The spectrum and geographic variability of its venom toxins were investigated applying a venomics approach to venom pools from five geographic areas within the Caatinga ecoregion. Despite its wide habitat, populations of B. erythromelas from Ceará, Pernambuco, Juazeiro, Paraiba, and Ilha de Itaparica exhibit highly conserved venom proteomes. Mirroring their compositional conservation, the five geographic venom pools also showed qualitatively and quantitatively overlapping antivenomic profiles against antivenoms generated in Vital Brazil (BR) and Clodomiro Picado (CR) Institutes, using different venoms in the immunization mixtures. The paraspecificity exhibited by the Brazilian SAB and the Costa Rican BCL antivenoms against venom toxins from B. erythromelas indicates large immunoreactive epitope conservation across genus Bothrops during the last ~14 million years, thus offering promise for the possibility of generating a broad-spectrum bothropic antivenom. Biological Significance Accidental snakebite envenomings represent an important public health hazard in Brazil. Ninety per cent of the yearly estimated 20-30,000 snakebite accidents are caused by species of the Bothrops genus. Bothrops erythromelas, a small, moderately stocky terrestrial venomous snake, is responsible for most of the snakebite accidents in its broad distribution range in the Caatinga, a large ecoregion in northeastern Brazil. To gain a deeper insight into the spectrum of medically important toxins present in the venom of the Caatinga lancehead, we applied a venomics approach to define the proteome and geographic variability of adult B. erythromelas venoms from five geographic regions. Although intraspecific compositional variation between venoms among specimens from different geographic regions has long been appreciated by herpetologists and toxinologists as a general feature of highly adaptable and widely distributed snake species, the five B. erythromelas populations investigated exhibit highly conserved venom proteomes. The overall toxin profile of the Caatinga lancehead's venom explains the local and systemic effects observed in envenomations by B. erythromelas. The five geographic venom pools sampled also showed qualitatively and quantitatively overlapping antivenomic profiles against antivenoms generated using different bothropic venoms in the immunization mixtures. The large immunoreactive epitope conservation across genus Bothrops offers promise for the generation of a broad-spectrum bothropic antivenom.

Abarema cochliacarpos extract decreases the inflammatory process and skeletal muscle injury induced by Bothrops leucurus venom

Snakebites are a public health problem, especially in tropical countries. However, treatment with antivenom has limited effectiveness against venoms' local effects. Here, we investigated the ability of Abarema cochliacarpos hydroethanolic extract (EAc) to protect mice against injection of Bothrops leucurus venom. Swiss mice received perimuscular venom injection and were subsequently treated orally with EAc in different doses. Treatment with EAc 100, 200, and 400 mg/kg reduced the edema induced by B. leucurus in 1%, 13%, and 39%, respectively. Although lower doses showed no antihypernociceptive effect in the Von Frey test, the higher dose significantly reduced hyperalgesia induced by the venom. Antimyotoxic activity of EAc was also observed by microscopy assessment, with treated muscles presenting preserved structures, decreased edema, and inflammatory infiltrate as compared to untreated ones. Finally, on the rotarod test, the treated mice showed better motor function, once muscle fibers were preserved and there were less edema and pain. Treated mice could stand four times more time on the rotating rod than untreated ones. Our results have shown that EAc presented relevant activities against injection of B. leucurus venom in mice, suggesting that it can be considered as an adjuvant in the treatment of envenomation.

Epidemiology of snakebite accidents in the municipalities of the state of Paraíba, Brazil

Accidents involving venomous animals represent an important, albeit neglected, public health issue worldwide. A descriptive study was made of snakebite cases attended and recorded between 2007 and 2010 in the health units of the municipalities of Cariri, State of Paraíba, northeastern Brazil. Data was collected from the Injury Notification Information System data banks of the Health Ministry and a total of 351 records of snakebite victims were reviewed. Victims were predominantly male farm workers over 50. The highest incidence of snakebites occurred in rural areas, between April and June of 2007 and 2010. Snakes of the genus Bothrops were responsible for most cases, and victims were mostly bitten on the feet. The majority of the victims received medical assistance within 1 to 3 hours after being bitten. The most common clinical manifestations were pain, edema and ecchymosis, which were mainly classified as mild or moderate. Two deaths were reported. It was concluded that there is a significant impact of seasonality in snakebites, the prevalence of attacks caused by Bothrops, affecting the lower limbs of adult male farmers in rural areas. The findings of this study may contribute to identify the conditions that increase the risk of snake attacks in the northeastern region.

The international view of envenoming in Brazil: myths and realities

Being distant from Brazil’s great natural diversity, from its long tradition in the study of snakebites and from the fact that it is one of the few countries which has a national information system for monitoring incidents involving venomous animals, non-Brazilian researchers face risks when estimating the incidence of these accidents in the country. The present work offers a critical review of the main estimates undertaken since 1954. It is interesting to note contradictions between textual and graphic information within the same article, variations over time in the work of a same researcher and differences among distinct authors, and that all these issues remain unmentioned or undiscussed. Comparison among such estimates and the data available at the Brazilian Information System on Diseases of Compulsory Declaration (Sistema de Informação de Agravos de Notificação – SINAN) creates an opportunity to identify the degree of imprecision present in those articles, and draws attention to the need for the production of studies at both the regional and national levels, based on concrete data collected at national, state and municipal levels, which has been available on the internet since 2001.

Fatal snake bites - sociodemography, latency pattern of injuries

BACKGROUND

India is a thickly populated country; apart from having biodiversity among people, climate does change from place to place. Western Ghats of South India harbors variety of plantations and diverse creatures. Agriculture is the primary occupation of the people and some tribes living in these regions. Here majority are callous/ ignorant in employing neither advanced farming techniques nor safety precautions, hence are exposed to bites and stings by animals. Of these, snake bites cause significant mortality and morbidity. Proper care for some of these individuals is out of reach. Identification of offending snake, snake bite injury or findings of envenomation is a key not only for the administration of antisnake venom but also for the victim to realize that he needs an expert care. Unless he believes it to be a critical snake bite and not a thorn prick, scorpion sting or a spider bite he will not approach a health care provider. To know about these dangerous signs that may help the victim to realize it as a case of snake bite, current study is employed on fatal cases in this region.

METHODS

60 fatal snakebite cases were studied retrospectively for 5 years with an objective to know the socio-demography, latency and pattern of injuries in rural Southern India.

RESULTS

Most of the victims were males, in the age group of 31-50 years and were at risk of snake bites while farming. Large sample of subjects approached traditional therapists and were deprived of essential care in the critical first few hours after snake bite. Fang marks (90%), local ecchymoses (50%) and internal hemorrhage (28.3%), were the frequent demonstrable signs appreciated at autopsy.

CONCLUSION

Snakebite is a neglected, endemic, occupational (farming) disease of the poor and there is need for National Snakebite Prevention Programme for curtailing this menace.

Antiophidic activity of the extract of the Amazon plant Humirianthera ampla and constituents

ETHNOPHARMACOLOGICAL RELEVANCE

Although serotherapy against snakebite has been discovered more than one hundred years ago, antivenom is not available all over Brazil. The use of plants from folk medicine is common mainly in the Brazilian Amazon area. One of these plants is named Humirianthera ampla (HA).

MATERIALS AND METHODS

We have investigated HA extract and constituents' antiophidic activity in different experimental protocols against some Bothrops snake venoms (Bothrops jararacussu, Bothrops atrox and Bothrops jararaca). The protocols investigated include phospholipase, proteolytic, pro-coagulant, hemorrhagic, edematogenic and myotoxic activities induced by these venoms in Swiss mice.

RESULTS

All the venoms caused an increase in the rate of creatine kinase (CK) release from isolated muscles, indicating damage to the sarcolemma. The crude extract of HA decreased the myotoxic activity in a concentration-dependent fashion. The presence of HA 300 μg/mL decreased up to 96% of Bothrops jararacussu and 94% of Bothrops atrox myotoxicity after 90 min of exposure. In vivo myotoxicity of Bothrops atrox venom was decreased in 75% when the venom was preincubated with HA 500 mg/kg. Similar results were observed with lupeol against Bothrops jararacussu and Bothrops atrox venoms. The hemorrhagic activity was evaluated by intradermal injection of Bothrops atrox venom. Preincubation and oral pre- and posttreatment with HA decreased hemorrhage by 100%, 45% and 45%, respectively. Bothrops atrox venom also induced formation of edema, which was significantly inhibited by pre- and posttreatment with HA. All the venoms showed extensive pro-coagulating properties, and these activities were inhibited by up to 90% with HA, which presented concentration-dependent inhibition. Finally, proteolytic and phospholipase activities of the venoms were all inhibited by increasing concentrations of HA, lupeol and sitosterol. The inhibition of these activities might help explain the actions against in vivo myotoxicity and the in vivo effects observed, i.e., edema, myotoxicity, pro-coagulation and hemorrhage.

CONCLUSIONS

Altogether, our results give support for the popular use of HA extracts in cases of accidents with snakes, suggesting that it can be used as an adjunct in the management of venomous snakebites.

Isolation and characterization of moojenin, an acid-active, anticoagulant metalloproteinase from Bothrops moojeni venom

A fibrinogenolytic metalloproteinase from Bothrops moojeni venom, named moojenin, was purified by a combination of ion-exchange chromatography on DEAE-Sephacel and gel filtration on Sephacryl S-300. SDS-PAGE analysis indicated that moojenin consists of a single polypeptide chain and has a molecular mass about 45 kDa. Sequencing of moojenin by Edman degradation revealed the amino acid sequence LGPDIVSPPVCGNELLEVGEECDCGTPENCQNE, which showed strong identity with many other snake venom metalloproteinases (SVMPs). The enzyme cleaves the Aα-chain of fibrinogen first, followed by the Bβ-chain, and shows no effects on the γ-chain. Moojenin showed a coagulant activity on bovine plasma about 3.1 fold lower than crude venom. The fibrinogenolytic and coagulant activities of the moojenin were abolished by preincubation with EDTA, 1,10-phenanthroline and β-mercaptoethanol. Moojenin showed maximum activity at temperatures ranging from 30 to 40 °C and its optimal pH was 4.0. Its activity was completely lost at temperatures above 50 °C. Moojenin induced necrosis in liver and muscle, evidenced by morphological alterations, but did not cause histological alterations in mouse lungs, kidney or heart. Moojenin rendered the blood uncoagulatable when it was intraperitoneally administered into mice. This metalloproteinase may be of medical interest because of its anticoagulant activity.

Bite-to-hospital time and morbidity in victims of viper bite in a rural hospital in Nigeria

Background: Mortality amongst in-hospital patients bitten by carpet viper in northern Nigeria has reduced, related to use of a monospecific ovine Fab snake antivenom. However, many victims survive with temporary or permanent morbidity. Objectives: Study objectives were to: (1) determine and score the morbidity caused by carpet viper bite; and (2) find the relationship between bite-to-hospital time and morbidity amongst victims of carpet viper bite.Method: A prospective study was conducted in a rural hospital in north-central Nigeria. The morbidities scored were oedema, tenderness, prolonged whole-blood clotting time, blister, ulcer, need for blood transfusion, coma, hypotension, convulsion, length of hospital stay, need for disarticulation, and need for skin graft. A score of one was given to each objective sign. The bite-to-hospital time of 233 subjects was obtained. Descriptive and inferential statistical analysis was done.Results: Most of the subjects (150 or 64%) came to the hospital within 6 hours of the snake bite, with 2 (1%) arriving within 1 hour. The median bite-to-hospital time was 5 hours, with a range of 0.5–216 hours. Major morbidities were oedema, seen in 212 (91.0%; 95% CI 86.6–94.3%); incoagulable blood, seen in 205 (88%; 95% CI 83.1–91.9%), and tenderness, seen in 201 (86.3%; 95% CI 81.2–90.4%). The mean morbidity score was 8 ± 4. For every unit increase in logged bite-to-hospital time, the morbidity score increased by 1.85 (p < 0.001).Conclusion: Morbidity caused by carpet viper bite is high in Zamko, north-central Nigeria, and correlates with increasing bite-to-hospital time.

Low-level laser therapy promotes vascular endothelial growth factor receptor-1 expression in endothelial and nonendothelial cells of mice gastrocnemius exposed to snake venom

Crotalinae snake venoms cause severe local myonecrosis and microvasculature failure at the bite site. We evaluated whether low-level laser therapy (LLLT) could accelerate angiogenesis and myoregeneration in male Swiss mice injected with Bothrops moojeni venom through immunohistochemistry of the vascular endothelial growth factor receptor-1 (VEGFR-1). Envenomed gastrocnemius was either unirradiated (V) or irradiated with HeNe (VHN, 632.8 nm) or GaAs (VGA, 904 nm, 10000 Hz). Animals sacrificed at 3 and 12 h were irradiated once (4 J cm(-2)), at 24 h (twice) and at 3, 7, 21 days (4, 8, 22 times, respectively). At 3 days, LLLT increased angiogenesis (80%:HeNe vs 40%:GaAs), decreased neutrophils and increased proliferation of regenerating cells. However, after 21 days, myoregeneration observed in the VHN group appeared delayed compared with the V group. As LLLT improved revascularization, the suggestive delay in myoregeneration could be a dose-response inhibitory effect caused by multiple irradiations in myogenesis. The immunodetection of VEGFR-1 in neutrophils, macrophages, satellite cells, fibroblasts, Schwann cells and skeletal and smooth muscle fibers (not seen in saline-controls) at only the acute stages of envenoming suggests a mediator role for VEGFR-1 in local alterations. This is the first time that VEGFR-1 expression, and its modulation by photostimulation, has been demonstrated in endothelial and nonendothelial cells of snake envenomed skeletal muscle.

Snake envenoming: a disease of poverty

BACKGROUND

Most epidemiological and clinical reports on snake envenoming focus on a single country and describe rural communities as being at greatest risk. Reports linking snakebite vulnerability to socioeconomic status are usually limited to anecdotal statements. The few reports with a global perspective have identified the tropical regions of Asia and Africa as suffering the highest levels of snakebite-induced mortality. Our analysis examined the association between globally available data on snakebite-induced mortality and socioeconomic indicators of poverty.

METHODOLOGY/PRINCIPAL FINDINGS

We acquired data on (i) the Human Development Index, (ii) the Per Capita Government Expenditure on Health, (iii) the Percentage Labour Force in Agriculture and (iv) Gross Domestic Product Per Capita from publicly available databases on the 138 countries for which snakebite-induced mortality rates have recently been estimated. The socioeconomic datasets were then plotted against the snakebite-induced mortality estimates (where both datasets were available) and the relationship determined. Each analysis illustrated a strong association between snakebite-induced mortality and poverty.

CONCLUSIONS/SIGNIFICANCE

This study, the first of its kind, unequivocally demonstrates that snake envenoming is a disease of the poor. The negative association between snakebite deaths and government expenditure on health confirms that the burden of mortality is highest in those countries least able to deal with the considerable financial cost of snakebite.

Treatment with an anti-inflammatory drug is detrimental for muscle regeneration at Bothrops jararacussu envenoming: an experimental study

We evaluated the effects of deflazacort (DFZ) on muscle regeneration following Bothrops jararacussu envenoming. Tibialis anterior muscle from adult mice was injected with 80 microg of venom. Animals received DFZ during 6days. Seven and 60 days after envenoming, DFZ lead to a decrease in the total number of muscle fibers and an increase in interstitial fibrosis. We conclude that DFZ treatment may aggravate the loss of muscle mass after B. jararacussu envenoming.

Contextual analysis and epidemiology of spider bite in southern Santa Catarina State, Brazil

The aim of this work was to conduct an epidemiological and clinical review of 1126 cases of envenoming by spider recorded in the national notifiable diseases information system (SINAN) files of the Municipal Health Secretary of the Criciúma region, Santa Catarina State, Brazil from 1994 to 2006. This work presents a critical analysis carried out by the application of the chi(2) test, with different regional contextual parameters, including the incidence coefficient. Spider envenoming accounts for more than 50% of all cases recorded in the SINAN files for poisonous animals and is the main cause of human envenomation in the Criciúma region. The majority of the spider bites (57.4%) were reported in the hottest months, from December to May. The anatomic region that suffered the most bites was the hand. Nearly 50% of the accidents were recorded in the group aged 20-49 years. The spiders most frequently involved in accidents for all age groups were of the Loxosceles genus. Although the data collected lack further epidemiological and, especially, clinical details, this does not affect the conclusions of the study, which could be used in the planning of actions aimed at improving environmental health.

Proteomic analysis of the venom from the fish eating coral snake Micrurus surinamensis: novel toxins, their function and phylogeny

The protein composition of the soluble venom from the South American fish-eating coral snake Micrurus surinamensis surinamensis, here abbreviated M. surinamensis, was separated by RP-HPLC and 2-DE, and their components were analyzed by automatic Edman degradation, MALDI-TOF and ESI-MS/MS. Approximately 100 different molecules were identified. Sixty-two components possess molecular masses between 6 and 8 kDa, are basically charged molecules, among which are cytotoxins and neurotoxins lethal to fish (Brachidanios rerio). Six new toxins (abbreviated Ms1-Ms5 and Ms11) were fully sequenced. Amino acid sequences similar to the enzymes phospholipase A2 and amino acid oxidase were identified. Over 20 additional peptides were identified by sequencing minor components of the HPLC separation and from 2-DE gels. A functional assessment of the physiological activity of the six toxins was also performed by patch clamp using muscular nicotinic acetylcholine receptor assays. Variable degrees of blockade were observed, most of them reversible. The structural and functional data obtained were used for phylogenetic analysis, providing information on some evolutionary aspects of the venom components of this snake. This contribution increases by a factor of two the total number of alpha-neurotoxins sequenced from the Micrurus genus in currently available literature.

Stroke and snakebite: case report

Snakebites are common and lead to potential complications like neuromyopathies and strokes, these last associated with disturbances of blood coagulation. We report on a 65 years old woman of cerebral intraparenchymal hemorrhage associated with snakebite by a Bothrops jararaca that occurred in the Reconcavo of Bahia, BA, Brazil. The patient was submitted to a surgical evacuation of the hematoma, with a good result. This report is accompanied by a revision about the association among snakebite and neurological complications, emphasizing strokes. Statistics reveal a high incidence of snakebite in the world, mainly in tropical countries and gets attention for his socioeconomic impact. The clinical and laboratory characteristics to identify the victims that present a high risk of presenting strokes are discussed in order to identify early those patients, so that they may be treated in a more precocious and effective way.

Envenenamento por serpentes do gênero Bothrops no Estado da Bahia: aspectos epidemiológicos e clínicos

Descreve-se características clínico-epidemiológicas de 655 casos de acidentes botrópicos atendidos e/ou notificados ao Centro de Informações Antiveneno da Bahia, no Estado da Bahia, em 2001. A incidência anual no Estado foi de 5,0 acidentes/100.000 habitantes e a letalidade, 1%. A incidência foi máxima na microrregião Litoral Norte (21,9/100.000 habitantes) e no município de Itanagra (92,9/100.000 habitantes). Os acidentes foram predominantemente diurnos, acometendo membros inferiores, em homens, de 11-30 anos, trabalhadores, no ambiente rural e no período chuvoso. Atendimento médico após 13 horas da ocorrência da picada ocorreu em 19% dos casos. Predominaram os quadros clínicos moderados (47,8%), seguidos dos graves (23,6%). As manifestações clínicas locais e sistêmicas seguiram o padrão nacional para as serpentes do gênero Bothrops. Sintomatologias neurológicas, não usualmente atribuídas ao acidente botrópico, foram registrados em alguns casos. A soroterapia empregada (7,7 ampolas/paciente) foi compatível com o fato da maioria de casos serem moderados. Outros tipos de soro que não o univalente foram utilizados em 15 (2,3%) pacientes.

Microvessel damage by B. jararacussu snake venom: pathogenesis and influence on muscle regeneration

The loss of muscle mass consequent to poor muscle regeneration is a common sequela following the injection of Bothrops jararacussu snake venom. Since an intact microvasculature plays a central role in the success of muscle regeneration, the poor muscle regeneration seen after envenomation could be explained by damage to the local microvasculature. In this work, we investigated the pathogenesis of microvessel damage caused by B. jararacussu venom and its correlation with poor muscle regeneration. The right soleus muscle of adult mice was injected with 80 microg of venom and the mice were killed from 2 min to 3 months later. Similarly, the soleus muscle of other mice was injected with 80 microg of bothrosptoxin-I (BthTX-I), a non-vasculotoxic myotoxin. Tissue samples were prepared for analysis by electron (venom only) and light (venom and BthTX-I) microscopy. The extent of revascularization was assessed using light microscopy by examining recanalization of thrombi and calculating the individual capillary-to-fiber-ratio, the number of capillaries around a fiber and the capillary/muscle cell ratio. Microvessel damage by venom started within 5 min and, after 6 h, there was total degeneration of the capillaries with failure of the local microcirculation. The time-course of the ultrastructural lesions suggested that endothelial cells were probably damaged by a direct action of B. jararacussu venom on these cells. The revascularization of muscle damaged by venom, but not by BthTX-I, occurred later and was very poor. These results indicate a central role for vascular lesions in muscle regeneration after damage by B. jararacussu venom.

Insights into the loss of muscle mass following B. jararacussu venom in mice

Bothrops jararacussu snake venom produces myonecrosis and nerve degeneration. In this work, we investigated whether nerve lesions or impaired muscle regeneration contributed to the permanent loss of muscle mass, a long-term sequela of envenoming. The right soleus muscle of adult male mice was injected with B. jararacussu venom (80 microg) while the left muscle received only saline (control). The mice were killed after 2 and 3 months and the muscles were removed and processed for examination by transmission electron microscopy and light microscopy. The nerve fibers, Schwann cells and neuromuscular junctions had regenerated in venom-treated muscle. The total number of muscle fibers was significantly lower (p<0.05) than in the control (617+/-48 versus 1235+/-97, respectively; mean+/-SEM, n=10). These results show that the loss of muscle mass was most likely related to a decrease in the ability of the muscle to regenerate rather than to nerve lesions.