Implications of global environmental change for the burden of snakebite

Datura alba seed proteins effect on snake venom enzymes with antioxidant and antibacterial activities

Objective

This study assessed the inhibitory potential of proteins extracted from Datura alba seeds on snake venom toxic enzymes along with their potential antioxidant and antibacterial activities.

Methods

Crude proteins were extracted using common biological buffers (20 mM acetate, 20 mM phosphate and 20 mM Tris) at a ratio of 1:5 followed by 80 % ammonium sulfate precipitation, dialysis, and lyophilization. Then the lyophilized extracts were resolved on 15 % sodium dodecyl sulfate polyacrylamide electrophoresis (SDS-PAGE) gels. The Tris extract showing the maximum number of protein bands on the SDS gel was further assessed for inhibitory bioactivities. Specifically, the agar well diffusion method was performed to assess the inhibitory activities of phospholipase A2 (PLA2), protease, and α-amylase using 2 % egg yolk, 5 % skim milk and 1 % starch as substrates, respectively. Naja naja, Echis carinatus venom, and human saliva were used as sources of PLA2, protease, and amylase, respectively, to test the inhibitory activity of the extract on these enzymes. Antioxidant activity was determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay using ascorbic acid as a standard. Antibacterial activity was assessed by the agar well diffusion method using Escherichia coli and Staphylococcus aureus as bacterial sources.

Results

The Tris extract of seed proteins exhibited 19 % inhibition of snake venom PLA2 at a concentration of 125 μg/μL concentration, whereas no venom protease inhibition or antibacterial activity was observed at the highest concentrations analyzed. Significant antioxidant activity (44.9 %) was observed at 600 μg/μL, while α-amylase-enhancing activity in a concentration-dependent manner was noted.

Conclusion

The results of this study demonstrated snake venom PLA2 neutralization, which is a major toxic enzyme present in snake venom, along with significant antioxidant properties. This study highlights the potential of Datura seed proteins as an antiophidic along with other therapeutically important applications.

A systematic review of variables associated with snakebite risk in spatial and temporal analyses

BACKGROUND

Snakebite is a priority neglected tropical disease, but incidence data are lacking; current estimates rely upon incomplete health facility reports or ad hoc surveys. Spatial analysis methods harness statistical associations between case incidence and spatially varying factors to improve estimates. This systematic review aimed to identify variables associated with snakebite risk in spatial and temporal analyses for inclusion in geospatial studies to improve risk estimation accuracy.

METHODS

We searched MEDLINE, Global Health, PubMed and Web of Science in January 2023 for studies published since 1980 assessing snakebite outcomes and spatially varying factors at the setting level. Study quality was assessed using an adapted Joanna Briggs Institute tool. The results are presented by narrative synthesis.

RESULTS

Thirty-five studies were eligible; the majority were from Central and South America (18), then Asia (11). Climate and environment were most frequently assessed, with temperature, humidity and tree cover predominantly positively associated with snakebite risk, drought negatively associated and altitude negative/mixed. Crop and livestock variables mostly showed positive associations; population density and urban residence overwhelmingly displayed negative associations.

CONCLUSIONS

This review identifies key variables that should be considered in future snakebite risk research. Limitations include low research availability from the highest risk regions. There is an evident need for greater research into snakebite risk variation, particularly in sub-Saharan Africa.

Clinico-Epidemiological Profile, Trends, and Health-Related Outcomes of Snakebite Victims: A One-Year Prospective Study from Eastern India

INTRODUCTION

Snakebite envenomation is a significant life-threatening public health problem in Southeast Asia (SEA). In this region, India reported the largest number of snakebite deaths from 2000 to 2019 (1.2 million), with an average of 58,000 deaths yearly.

METHODS

This prospective observational study was carried out among snakebite victims at the emergency department (ED) of a tertiary care public sector hospital in eastern India.

RESULTS

A total of 145 cases of venomous snakebite were investigated. More than half (n = 81, 56%) of the snakebite victims were between 17 to 45 years. Most of the snakebite victims were male (68%) and were farmers (53%) by occupation. The majority of snakebites occurred during the daytime (76%) and while outdoors (67%). Most victims sustained a bite on the lower extremity (71%). The peak incidence of snakebites occurred from June to September (69%). Three-quarters of all patients were unaware of the required first aid measures following a snakebite. Among the 145 venomous snakebites, 48 were presumptively identified as the Indian cobra, 32 by the Indian krait, 56 by the Russel's viper, and 9 by saw-scaled viper. The mean duration from the snakebite to the onset of systemic effects in the Indian cobra was 52 ± 14.28 min, 66 ± 18.35 min in the Indian krait, 42 ± 13.47 min in Russel's viper, and 48 ± 16.38 min in saw-scaled viper. Respiratory failure was the commonly observed complication following an elapid envenomation. The mortality rate was 2.1% among the patients treated with antivenom.

CONCLUSIONS

Snakebite is considered an occupational hazard in India, commonly affecting the young population in their productive period. The peak incidence was during monsoon season, and the majority had neurotoxic envenomation following an elapid bite (55%) that contributed to the increased mortality and morbidity among young adults. Of the 145 patients, the majority (84%) recovered fully with treatment; 16% of the victims developed morbidity viz cellulitis, respiratory failure, acute renal failure, compartment syndrome, local tissue necrosis, intracerebral hemorrhage, and disseminated intravascular coagulation. Appropriate first aid measures and timely medical intervention can significantly improve the treatment outcome following snakebites.

Analysis of News Media-Reported Snakebite Envenoming in Nepal during 2010-2022

BACKGROUND

Snakebite envenoming is a well-known medical emergency in the Terai of Nepal in particular. However, there is an epidemiological knowledge gap. The news media data available online provide substantial information on envenomings. Assessing this information can be a pristine approach for understanding snakebite epidemiology and conducting knowledge-based interventions. We firstly analyzed news media-reported quantitative information on conditions under which bites occur, treatment-seeking behavior of victims, and outcomes of snakebite envenomings in Nepal.

METHODOLOGY/PRINCIPAL FINDINGS

We analyzed 308 Nepalese snakebite envenomed cases reported in 199 news media articles published between 2010 and 2022 using descriptive statistics, Wilcoxon, and Chi-square tests to know why and how victims were bitten, their treatment-seeking behavior, and the outcomes. These envenomated cases known with substantial information represented 48 districts (mostly located in the Terai region) of Nepal. These envenomings mostly occurred in residential areas affecting children. Generally, envenomings among males and females were not significantly different. But, in residential areas, females were more envenomed than males. Further, victims' extremities were often exposed to venomous snakebites while their active status and these episodes often occurred at night while victims were passive during snakebites indoors and immediate surroundings of houses. Snakebite deaths were less among referred than non-referred cases, males than females, and while active than passive conditions of victims.

CONCLUSION/SIGNIFICANCE

The most of reported envenomed patients were children, and most envenomings were due to cobra bites. Consultation with traditional healers complicated snakebite management. In most cases, deaths that occur without medical interventions are a severe snakebite consequence in Nepal. Further, several deaths in urban areas and mountains and higher hills of Nepal suggest immediate need of snakebite management interventions in the most affected districts. Therefore, there is an urgent need to immediately admit Nepalese snakebite victims to nearby snakebite treatment centers without adopting non-recommended prehospital interventions. The strategies for preventing snakebite and controlling venom effects should also include hilly and mountain districts where snakebite-associated deaths are reported.

Identifying high snakebite risk area under climate change for community education and antivenom distribution

Snakebite is one of the largest risks from wildlife, however little is known about venomous snake distribution, spatial variation in snakebite risk, potential changes in snakebite risk pattern due to climate change, and vulnerable human population. As a consequence, management and prevention of snakebite is hampered by this lack of information. Here we used habitat suitability modeling for 10 medically important venomous snakes to identify high snakebite risk area under climate change in Iran. We identified areas with high snakebite risk in Iran and showed that snakebite risk will increase in some parts of the country. Our results also revealed that mountainous areas (Zagros, Alborz, Kopet-Dagh mountains) will experience highest changes in species composition. We underline that in order to improve snakebite management, areas which were identified with high snakebite risk in Iran need to be prioritized for the distribution of antivenom medication and awareness rising programs among vulnerable human population.

Current situation of snakebites envenomation in the Neotropics: Biotechnology, a versatile tool in the production of antivenoms

Snakebite envenomation is a neglected tropical disease that affects millions of people around the world with a great impact on health and the economy. Unfortunately, public health programs do not include this kind of disease as a priority in their social programs. Cases of snakebite envenomations in the Neotropics are inaccurate due to inadequate disease management from medical records to the choice of treatments. Victims of snakebite envenomation are primarily found in impoverished agricultural areas where remote conditions limit the availability of antivenom. Antivenom serum is the only Food and Drug Administration-approved treatment used up to date. However, it has several disadvantages in terms of safety and effectiveness. This review provides a comprehensive insight dealing with the current epidemiological status of snakebites in the Neotropics and technologies employed in antivenom production. Also, modern biotechnological tools such as transcriptomic, proteomic, immunogenic, high-density peptide microarray and epitope mapping are highlighted for producing new-generation antivenom sera. These results allow us to propose strategic solutions in the Public Health Sector for managing this disease. Keywords: antivenom, biotechnology, neglected tropical disease, omics, recombinant antibody.

Assessment of Risk Factors, Prehospital Measures and Clinical Needs of Patients Admitted With Snake Envenomation at a Rural Hospital in Trinidad and Tobago

Objective: This study assessed the risk factors for sustaining a snake bite, the prehospital measures employed, and the clinical needs of patients admitted with confirmed envenomation.

Methodology: Data was collected at a single center, a rural secondary care hospital in Trinidad and Tobago. A cross-sectional method was used that enrolled all consenting patients requiring admission following clinical confirmation of snake envenomation during the period 2017-2019. Data collection involved a review of the patient record from the emergency room and hospital admission to establish the clinical need during the time of admission which was defined as the administration of medication, need for surgery, and critical care intervention. Data collection also involved a patient interview to establish demographics, prehospital measures employed, and assessment of the risk factors associated with sustaining the snake bite.

Results: 29 patients were admitted for snakebite envenomation during 2017-2019 and all patients consented to enrolment. Of these patients, 22 were male and most commonly were within the age range of 18-40 years old. 34.5% of patients were farmers and 68.9% of patients identified being bitten by the Mapepire Balsain snake. 65.5% of patients reported being unaware of the risk of snake bites and 82.8% were not wearing boots, with the lower limb being the most common bite site among 55.2%. 41.4% of bites were sustained during work-related activity while 34.5% of bites were sustained during recreational activity. Prehospital measures were employed by 18 of the 29 patients with the most common types being irrigation (10.3%), cutting (6.9%), tourniquets (44.8%), pressure immobilization (6.9%), topical applications (3.4%), and ingestion of a substance (6.9%). 34.5% received hospital care within 1 hour of the bite while 55.2% arrived at the hospital between 1 and 4 hours of being bitten. The clinical challenges of these patients included local reactions (82.8%), coagulopathy (72.4%), compartment syndrome (17.2%), cellulitis (3.4%), and dislocated shoulder (3.4%). The clinical needs of these patients included vitamin K (13.8%), antibiotics (93.1%), tetanus shots (17.2%), analgesia (6.8%), and anti-venom (82.7%). 10.3% of patients required debridement and 3.4% required a fasciotomy. The average stay in the hospital was 3.8 days. There were no documents of deaths or need for critical care.

Conclusion: Persons are most likely to be envenomated by the M. Balsain in Trinidad. These patients are commonly males ranging anywhere from 18 to 40 years presenting local reactions and coagulopathy needing admittance to the hospital. While the majority of patients requiring admission performed some type of prehospital measure, very few did so with pressure immobilization. Furthermore, the majority of patients had a prolonged time before presenting to the hospital; this is a potential area for improvement in the health system through education and sensitization. There was a significant utilization of resources on these patients when taking into consideration their clinical needs, medication, and hospital stay; primary prevention should be a focus through the education of groups who are at higher risk for a venomous snake encounter.