Rattlesnakes bites in the Brazilian Amazon: Clinical epidemiology, spatial distribution and ecological determinants

Early-Onset Respiratory Muscle Paralysis in Crotalic Envenomation: A Case Study

Crotalic envenomation is responsible for approximately 8%-13% of ophidism cases in Brazil, yet it is associated with the highest mortality among snakes. We describe the case of a patient bitten by a rattlesnake who developed ventilatory muscle paralysis within hours after envenomation. While diaphragmatic paralysis is a rare late neurotoxic event following crotalic envenomation, in this case, paralysis occurred early but was rapidly reversed after antivenom administration. This report discusses potential contributing factors based on a comprehensive literature review.

A retrospective analysis of epidemiology, clinical features of envenomation, and in-patient management of snakebites in a model secondary hospital of Assam, North-east India

Assam, a Northeastern State of India, is inhabited by several venomous snake species causing substantial morbidity and mortality. The data on the epidemiology of snakebites and their management is underreported in this region. Hence, a secondary health-based retrospective study was carried out at Demow Model Hospital, Sivasagar, Assam, to evaluate the clinical and epidemiological profile of snakebite cases reported in this rural hospital and their management. Snakebites occurring between April 2018 to August 2022 were reviewed based on socio-demographic details of the patient, clinical symptoms, and treatment using a standard questionnaire. Out of the 1011 registered snakebite cases, 139 patients (13.7%) counted for venomous bites, among which 92 patients (66.19%) accounted for viper bites (green pit viper and Salazar's pit viper), and 30 patients (21.5%) were bitten by elapid snakes (Indian monocled Cobra, banded krait, and greater/lesser black krait). A maximum number of snakebite cases (80.5%) were reported from the interior rural villages and documented from July to September (51.3%). Elapid snake envenomed patients, except one, were successfully treated with commercial antivenom, neostigmine, and glycopyrrolate. Because commercial polyvalent antivenom against "Big Four" venomous snakes of India showed poor neutralization of pit-vipers envenomation; therefore, pit-viper bite patients were treated with repurposed drugs magnesium sulfate and glycerin compression dressing. Adverse serum reactions were reported only in 3 (11.1%) cases. The preventive measures and facilities adopted at the Demow Model Hospital significantly reduce snakebite death and morbidity; therefore, they can be s practised across various states in India as a prototype.

Biological and Medical Aspects Related to South American Rattlesnake Crotalus durissus (Linnaeus, 1758): A View from Colombia

In Colombia, South America, there is a subspecies of the South American rattlesnake Crotalus durissus, C. d. cumanensis, a snake of the Viperidae family, whose presence has been reduced due to the destruction of its habitat. It is an enigmatic snake from the group of pit vipers, venomous, with large articulated front fangs, special designs on its body, and a characteristic rattle on its tail. Unlike in Brazil, the occurrence of human envenomation by C. durisus in Colombia is very rare and contributes to less than 1% of envenomation caused by snakes. Its venom is a complex cocktail of proteins with different biological effects, which evolved with the purpose of paralyzing the prey, killing it, and starting its digestive process, as well as having defense functions. When its venom is injected into humans as the result of a bite, the victim presents with both local tissue damage and with systemic involvement, including a diverse degree of neurotoxic, myotoxic, nephrotoxic, and coagulopathic effects, among others. Its biological effects are being studied for use in human health, including the possible development of analgesic, muscle relaxant, anti-inflammatory, immunosuppressive, anti-infection, and antineoplastic drugs. Several groups of researchers in Brazil are very active in their contributions in this regard. In this work, a review is made of the most relevant biological and medical aspects related to the South American rattlesnake and of what may be of importance for a better understanding of the snake C. d. cumanensis, present in Colombia and Venezuela.

Epidemiological study of snakebite cases in Sikkim: Risk modeling with regard to the habitat suitability of common venomous snakes

Background

Snakebite envenoming is listed as category ‘A’ Neglected Tropical Disease. To achieve the target of WHO (World Health Organization) 2019, it becomes necessary to understand various attributes associated with snakebite including community awareness, improvisation of medical facilities and to map the potential distribution of venomous snakes responsible for the bite. Hence this study is conducted in Sikkim, India to understand the epidemiology of snakebite in Sikkim. The potential distribution and risk mapping of five common venomous snakes are done for effective management of snakebite cases.

Methods and findings

The snakebite cases registered in six district hospitals and four PHCs (Primary Health Centers) of Sikkim were collected from the year 2011 to 2018. Community survey was also conducted to supplement the data. Ecological Niche Modeling (ENM) was performed to predict the potential habitat of five common venomous snakes of Sikkim. The risk modeling of snakebite cases was done at the level of Gram Panchayat Unit (GPU) using Geographically Weighted Regression (GWR) and Ordinary Linear Square (OLS) model. We found higher number of male victims inflicted with snakebite envenomation. The potential distribution of the five venomous snakes showed satisfactory mean AUC (Area under Curve) value. Both the models showed significant positive association of snakebite cases with habitat suitability of the venomous snakes. Hospital data revealed no death cases whereas community data reported 24 deaths.

Conclusions

Death from snakebite reflected in community data but not in hospital data strongly indicates the people’s belief in traditional medicine. Though people of Sikkim have rich traditional knowledge, in case of snakebite traditional practices may be ineffective leading to loss of life. Sensitizing people and improving medical facilities along with proper transport facilities in rural areas might significantly reduce the snakebite casualties in the state.

Snakebite is a global burden especially inflicting despair and torment among agronomist rural population of the society. This study has been conducted in small state of Sikkim in India which has not been actually considered so far in any of the national statistical condensation of snakebite cases. There are around 19 venomous snakes found in Sikkim of which five common ones co-exist with humans. Such co-existence may lead to unintentional encounter posing life threatening snakebite. People of Sikkim have strong belief on traditional healers for treatment of snakebite which results in mortality and morbidity. The present epidemiological study provides the baseline information compiling both hospital and community data and predict the areas having higher risk of snakebite envenomation in Sikkim. This study will help the authorities for better preparedness to deal with snakebite emergency to achieve minimum or no mortality. Potential risk mapping will help the health department for stocking anti-venom in nearby health centers. Most importantly, this study will create awareness among the people and the authority about snakebite which is considered as neglected tropical disease.

Crotalus Durissus Ruruima: Current Knowledge on Natural History, Medical Importance, and Clinical Toxinology

Crotalus durissus ruruima is a rattlesnake subspecies mainly found in Roraima, the northernmost state of Brazil. Envenomings caused by this subspecies lead to severe clinical manifestations (e.g. respiratory muscle paralysis, rhabdomyolysis, and acute renal failure) that can lead to the victim’s death. In this review, we comprehensively describe C. d. ruruima biology and the challenges this subspecies poses for human health, including morphology, distribution, epidemiology, venom cocktail, clinical envenoming, and the current and future specific treatment of envenomings by this snake. Moreover, this review presents maps of the distribution of the snake subspecies and evidence that this species is responsible for some of the most severe envenomings in the country and causes the highest lethality rates. Finally, we also discuss the efficacy of the Brazilian horse-derived antivenoms to treat C. d. ruruima envenomings in Roraima state.

Envenoming by the rattlesnake Crotalus durissus ruruima in the state of roraima, Brazil

The aim of this study was to evaluate the clinical-epidemiological factors associated with victims of rattlesnake envenoming in the state of Roraima, Brazil. In this location, rattlesnake accidents are caused by the subspecies Crotalus durissus ruruima. This is a prospective observational study carried out at the General Hospital of Roraima from april 2017 until july 2018. A total of 37 alleged rattlesnake victims had their medical records evaluated. However only one of them proved to be by C. d. ruruima. All individuals were residents from the savannas (lavrados) of Roraima. The town of Bonfim on the border between Brazil and Guyana had the highest occurrence of rattlesnake bites. The most affected group were males aged 13-20 years and farmers. The highest number of incidents occurred during daytime and lower limbs (feet) were the most major affected part of the body. Tourniquets were used as first aid after snake envenoming in 32.4% of victims. Out of 37 patients, 16.2% were classified as severe cases of snakebite envenoming and in 5.4% dry bites seem to have occurred. Among the symptomatic patients, 100% presented local manifestations and 70.3% presented systemic manifestations. The clinical setting showed local effects such as pain and edema while the systemic effects were blurred vision, myalgias, myasthenic facies, palpebral ptosis, muscle weakness and headache. Laboratory results of aspartate aminotransferase (62.2%), creatine phosphokinase (51.3%), lactic dehydrogenase (37.8%), urea level (32.4%) and serum creatinine (29.7%) were increased significantly in relation to the reference standards. In 16.2% of the cases, the victims presented acute kidney injury. Patients were treated with anticrotalic serum in 70.3% of the cases and antibotropic + anticrotalic serum in 24.3%. The victims of C. d. ruruima in Roraima showed a local symptomatology similar to Bothrops envenoming, while systemic symptoms and laboratory analysis proved kidney and muscular injuries, similar to envenoming by Crotalus d. terrificus in Brazil.

Envenomations by coral snakes in an Amazonian metropolis: Ecological, epidemiological and clinical aspects

Envenomation by coral snakes represents a little known burden in Brazilian Amazonia. So far, details on clinical and epidemiological aspects remain obscure in the region. We gathered data from medical charts and from the scientific collection of snakes from Fundação de Medicina Tropical Doutor Heitor Vieira Dourado, finding 26 cases of envenomation by five species of Micrurus in Manaus region, between 1987 and 2018. They represent 0.7% of the snakebites treated in the hospital since the records began, in 1979. Micrurus lemniscatus was responsible for most of the bites (10), followed by M. hemprichii (five), M. spixii (three), M. surinamensis (three) and M. averyi (one). There was no difference between the sexes of the snakes that caused bites. Patients were mostly males, and most of the cases were reported in urban areas. Bites predominated in dry season, and there was a clear geographical segregation among species. We describe seven cases of envenomation, three mild and four severe, all of which evolved to cure. Paresthesia (six), pain (five) and edema (four) were the most common local symptoms. Systemic features such as dyspnea/shallow breath (four), palpebral ptosis (four), blurred vision (three), dysarthria (three) and difficulty to walk (three) were also detected. Two patients bitten by Micrurus sp. and M. hemprichii, showed slight increased serum levels of creatine kinase (reference level <190 U/L), 1184 U/L and 1229 U/L, respectively, indicative of mild systemic myotoxicity. This is the first report of myotoxic manifestation in the envenomation by M. hemprichii. No patient developed respiratory failure, though one bitten by an adult M. spixii required intubation and mechanical ventilation due to decreased level of consciousness during evolution, probably related to induced sedation caused by concurrent alcohol intoxication. All patients were treated with Brazilian Micrurus antivenom (soro antielapídico, median = 10 vials). Six patients were pretreated intravenously with H1 and H2 antagonists and steroids, with two patients developing early adverse reactions. The median length of hospital stay was four days. Envenomations by coral snakes in Manaus region are clinically severe, but rare and sparsely distributed over time, making the detection of epidemiological and clinical patterns a challenge for public health.

Snakebites in Rio Branco and surrounding region, Acre, Western Brazilian Amazon

INTRODUCTION

Snakebites are considered a neglected tropical disease in many countries in Latin America, including Brazil. As few studies have assessed snakebites in the Amazon region and especially in the state of Acre, epidemiological studies are of great importance. The present study aimed to describe the epidemiological characteristics of snakebites in the Rio Branco region, observing their characteristics in rural and urban areas and their correlation with rainfall and river outflow.

METHODS

This retrospective, descriptive study analyzed epidemiological information obtained from snakebite notifications registered on the Information System for Notifiable Diseases that occurred from March, 2018 to February, 2019. The cases of snakebite were correlated with rainfall and flow.

RESULTS

A total of 165 cases of snakebite were registered in the period. Most cases were caused by Bothrops and affected mainly individuals of the male sex who were between 21 and 30 years old. Most of the snakebites occurred in Rio Branco (71.52%; 29 cases per 100,000 inhabitants). Of these, 60.2% occurred in the urban area and 39.8% in the rural area and the majority occurred during the rainy season.

CONCLUSIONS

Although studies have shown that a majority of cases occur in rural areas, in this study, urbanization of snakebites was observed. The Bothrops genus was responsible for the highest number of snakebites and, during the rainy season, bites occurred more frequently. Educational prevention campaigns, population advice, and first aid in case of snakebites for the population are thus suggested.

Bothrops atrox Snakebite: How a Bad Decision May Lead to a Chronic Disability: A Case Report

Snakebites are a neglected and underestimated global health hazard. In the Brazilian Amazon, Bothrops snakebites are the most prevalent and may lead to severe complications. Here we describe a severe case of Bothrops atrox snakebite that, owing to delayed medical assistance, presented with renal and respiratory failure, compartment syndrome, and tissue necrosis. After several fasciotomy surgeries, the patient survived; however, he showed significant functional disability. Prompt management of snake envenomation would aid in the early diagnosis of local and systemic complications and, consequently, would result in a better functional outcome with improved quality of life.

Clinical, Laboratory, and Therapeutic Aspects of Crotalus durissus (South American Rattlesnake) Victims: A Literature Review

Snakebite envenoming is a neglected public health issue in many tropical and subtropical countries. To diagnosis and treat snakebites may be challenging to health care personnel since sufficient information has not been yet provided. This review presents the clinical, therapeutic, and laboratory aspects of Crotalus durissus (South American rattlesnakes) victims. The clinical setting may show local effects such as little or no pain, mild edema, and recurrent erythema. In contrast, the systemic effects may be quite remarkable, such as changes due to neurological damage, intense rhabdomyolysis, incoagulability of the blood, and variations in the peripheral blood elements. The main complication is acute kidney injury. The appropriate treatment depends mainly on the correct recognition of the aggressor snake and the symptoms expressed by the victim. Rattlesnake venom can cause irreparable damage and lead to death. Therefore, a prompt diagnosis allows the immediate onset of proper serotherapy.