Crosstalk of Inflammation and Coagulation in Bothrops Snakebite Envenoming: Endogenous Signaling Pathways and Pathophysiology.

Snakebite envenoming represents a major health problem in tropical and subtropical countries. Considering the elevated number of accidents and high morbidity and mortality rates, the World Health Organization reclassified this disease to category A of neglected diseases. In Latin America, Bothrops genus snakes are mainly responsible for snakebites in humans, whose pathophysiology is characterized by local and systemic inflammatory and degradative processes, triggering prothrombotic and hemorrhagic events, which lead to various complications, organ damage, tissue loss, amputations, and death. The activation of the multicellular blood system, hemostatic alterations, and activation of the inflammatory response are all well-documented in Bothrops envenomings. However, the interface between inflammation and coagulation is still a neglected issue in the toxinology field. Thromboinflammatory pathways can play a significant role in some of the major complications of snakebite envenoming, such as stroke, venous thromboembolism, and acute kidney injury. In addition to exacerbating inflammation and cell interactions that trigger vaso-occlusion, ischemia-reperfusion processes, and, eventually, organic damage and necrosis. In this review, we discuss the role of inflammatory pathways in modulating coagulation and inducing platelet and leukocyte activation, as well as the inflammatory production mediators and induction of innate immune responses, among other mechanisms that are altered by Bothrops venoms.

CCL-2 and CXCL-8: Potential Prognostic Biomarkers of Acute Kidney Injury after a Bothrops atrox Snakebite.

In the Brazilian Amazon, the snake Bothrops atrox is the primary cause of snakebites. B. atrox (BaV) venom can cause systemic pathophysiological changes such as acute kidney injury (AKI), which leads to the production of chemokines and cytokines in response to the envenomation. These soluble immunological molecules act by modulating the inflammatory response; however, the mechanisms associated with the development of AKI are still poorly understood. Here, we characterize the profile of these soluble immunological molecules as possible predictive biomarkers of the development of AKI. The study involved 34 patients who had been victims of snakebites by Bothrops sp. These were categorized into two groups according to the development of AKI (AKI(-)/AKI(+)), using healthy donors as the control (HD). Peripheral blood samples were collected at three-time points: before antivenom administration (T0) and at 24 and 48 hours after antivenom (T1 and T2, respectively). The soluble immunological molecules (CXCL-8, CCL-5, CXCL-9, CCL-2, CXCL-10, IL-6, TNF, IL-2, IL-10, IFN-γ, IL-4, and IL-17A) were quantified using cytometric bead array. Our results demonstrated an increase in CXCL-9, CXCL-10, IL-6, IL-2, IL-10, and IL-17A molecules in the groups of patients who suffered Bothrops snakebites (AKI(-) and AKI(+)) before antivenom administration, when compared to HD. In the AKI(+) group, levels of CXCL-8 and CCL-2 molecules were elevated on admission and progressively decreased during the clinical evolution of patients after antivenom administration. In addition, in the signature analysis, these were produced exclusively by the group AKI(+) at T0. Thus, these chemokines may be related to the initiation and extension of AKI after envenomation by Bothrops and present themselves as two potential biomarkers of AKI at T0.

Exploring the Profile of Cell Populations and Soluble Immunological Mediators in Bothrops atrox Envenomations.

Bothrops atrox envenomations are common in the Brazilian Amazon. The venom of B. atrox is highly inflammatory, which results in severe local complications, including the formation of blisters. Moreover, there is little information on the immune mechanisms associated with this condition. Thus, a longitudinal study was carried out to characterize the profile of the cell populations and soluble immunological mediators in the peripheral blood and blisters in B. atrox patients s according to their clinical manifestations (mild and severe). A similar response in both B. atrox patient groups (MILD and SEV) was observed, with an increase in inflammatory monocytes, NKT, and T and B cells, as well as CCL2, CCL5, CXCL9, CXCL10, IL-1ß and IL-10, when compared with the group of healthy blood donors. After the administration of antivenom, the participation of patrolling monocytes and IL-10 in the MILD group was observed. In the SEV group, the participation of B cells was observed, with high levels of CCL2 and IL-6. In the blister exudate, a hyperinflammatory profile was observed. In conclusion, we revealed the involvement of cell populations and soluble mediators in the immune response to B. atrox envenomation at the local and peripheral level, which is related to the onset and extent of the inflammation/clinical manifestation.

Inflammatory Profile Associated with Secondary Infection from Bothrops atrox Snakebites in the Brazilian Amazon.

Bothrops snakebite envenomation (SBE) is consider an important health problem in Brazil, where Bothrops atrox is mainly responsible in the Brazilian Amazon. Local effects represent a relevant clinical issue, in which inflammatory signs and symptoms in the bite site represent a potential risk for short and long-term disabilities. Among local complications, secondary infections (SIs) are a common clinical finding during Bothrops atrox SBE and are described by the appearance of signs such as abscess, cellulitis or necrotizing fasciitis in the affected site. However, the influence of SI in the local events is still poorly understood. Therefore, the present study describes for the first time the impact of SBE wound infection on local manifestations and inflammatory response from patients of Bothrops atrox SBE in the Brazilian Amazon. This was an observational study carried out at the Fundação de Medicina Tropical Dr. Heitor Vieira Dourado, Manaus (Brazil), involving victims of Bothrops SBE. Clinical and laboratorial data were collected along with blood samples for the quantification of circulating cytokines and chemokines before antivenom administrations (T0) and 24 h (T1), 48 h (T2), 72 h (T3) and 7 days after (T4). From the 94 patients included in this study, 42 presented SI (44.7%) and 52 were without SI (NSI, 55.3%). Patients classified as moderate envenoming presented an increased risk of developing SI (OR = 2.69; CI 95% = 1.08-6.66, p = 0.033), while patients with bites in hands showed a lower risk (OR = 0.20; CI 95% = 0.04-0.96, p = 0.045). During follow-up, SI patients presented a worsening of local temperature along with a sustained profile of edema and pain, while NSI patients showed a tendency to restore and were highlighted in patients where SI was diagnosed at T2. As for laboratorial parameters, leukocytes, erythrocyte sedimentation ratio, fibrinogen and C-reactive protein were found increased in patients with SI and more frequently in patients diagnosed with SI at T3. Higher levels of circulating IL-2, IL-10, IL-6, TNF, INF-γ and CXCL-10 were observed in SI patients along with marked correlations between these mediators and IL-4 and IL-17, showing a plurality in the profile with a mix of Th1/Th2/Th17 response. The present study reports for the first time the synergistic effects of local infection and envenoming on the inflammatory response represented by local manifestations, which reflected on laboratorial parameters and inflammatory mediators and thus help improve the clinical management of SI associated to Bothrops SBE.

Severe tissue complications in patients of Bothrops snakebite at a tertiary health unit in the Brazilian Amazon: clinical characteristics and associated factors.

INTRODUCTION: Snakebites in the Brazilian Amazon are caused mostly by snakes from the Bothrops genus and envenomated patients may suffer from tissue complications. METHODS: This study aimed to identify risk factors for severe tissue complications (STC) in patients with Bothrops snakebite in the Amazonas state, Brazil. RESULTS: Snakebites that were classified as severe and affected female patients with comorbidities presented greater risks of developing STCs. In addition, hospitalizations of patients with STC exceeded 5 days. CONCLUSIONS: Clinical and epidemiological characteristics can prove essential for assessing the evolution of STC and clinical prognosis of patients with Bothrops snakebites.

A painful journey to antivenom: The therapeutic itinerary of snakebite patients in the Brazilian Amazon (The QUALISnake Study).

Access to antivenoms is not guarranteed for vulnerable populations that inhabit remote areas in the Amazon. The study of therapeutic itineraries (TI) for treatment of snakebites would support strategies to provide timely access to users. A TI is the set of processes by which individuals adhere to certain forms of treatment, and includes the path traveled in the search for healthcare, and practices to solve their health problems. This study aims to describe TIs of snakebite patients in the Brazilian Amazon. This study was carried out at the Fundação de Medicina Tropical Doutor Heitor Vieira Dourado, in Manaus, state of Amazonas, Brazil. The itinerary from the moment of the bite to the patient's admission to the reference unit was analyzed. Sample size was defined by saturation. After an exploratory survey to collect epidemiological variables, in-depth interviews were conducted following a semi-structured guide. Patients originated from rural areas of 11 different municipalities, including ones located >500 kilometers from Manaus. A great fragmentation was observed in the itineraries, marked by several changes of means of transport along the route. Four themes emerged from the analysis: exposure to snakebite during day-to-day activities, use of traditional therapeutic practices, and personal perception of the severity, as well as the route taken and its contingencies. Access to healthcare requires considerable effort on the part of snakebite patients. Major barriers were identified, such as the low number of hospitals that offer antivenom treatment, poor access to healthcare due to long distances and geographic barriers, low acceptability of healthcare offered in countryside, lack of use of personal protective equipment, common use of ineffective or deleterious self-care practices, late recognition of serious clinical signs and resistance to seeking medical assistance. Health education, promotion of immediate transport to health centers and decentralization of antivenom from reference hospitals to community healthcare centers in the Brazilian Amazon are more effective strategies that would to maximize access to antivenom treatment.

Bee sting envenomation severe cases in Manaus, Brazilian Amazon: clinical characteristics and immune markers of case reports.

Bee venom is a natural toxin composed of several peptides. Massive envenoming causes severe local and systemic reactions. We report two cases of severe bee envenomation, of which one was fatal. We also describe clinical characteristics and immune markers. Both victims suffered from respiratory distress, renal failure, rhabdomyolysis, and shock. They required invasive mechanical ventilation, vasoactive drugs, and renal replacement therapy. Moreover, serum levels of chemokines, cytokines, and cell-free circulating nucleic acids demonstrated an intense inflammatory process. Massive envenoming produced systemic injury in the victims, with an uncontrolled inflammatory response, and a more significant chemotactic response in the fatal case.

Correlating Fibrinogen Consumption and Profiles of Inflammatory Molecules in Human Envenomation's by Bothrops atrox in the Brazilian Amazon.

Snakebites are considered a major public health problem worldwide. In the Amazon region of Brazil, the snake Bothrops atrox (B. atrox) is responsible for 90% of the bites. These bites may cause local and systemic signs from acute inflammatory reaction and hemostatic changes, and present common hemorrhagic disorders. These alterations occur due the action of hemostatically active and immunogenic toxins which are capable of triggering a wide range of hemostatic and inflammatory events. However, the crosstalk between coagulation disorders and inflammatory reaction still has gaps in snakebites. Thus, the goal of this study was to describe the relationship between the consumption of fibrinogen and the profile of inflammatory molecules (chemokines and cytokines) in evenomations by B. atrox snakebites. A prospective study was carried out with individuals who had suffered B. atrox snakebites and presented different levels of fibrinogen consumption (normal fibrinogen [NF] and hypofibrinogenemia [HF]). Seventeen patients with NF and 55 patients with HF were eligible for the study, in addition to 50 healthy controls (CG). The molecules CXCL-8, CCL-5, CXCL-9, CCL-2, CXCL-10, IL-6, TNF, IL-2, IL-10, IFN-γ, IL-4, and IL-17A were quantified in plasma using the CBA technique at three different times (pre-antivenom therapy [T0], 24 h [T1], and 48 h [T2] after antivenom therapy). The profile of the circulating inflammatory response is different between the groups studied, with HF patients having higher concentrations of CCL-5 and lower IFN-γ. In addition, antivenom therapy seems to have a positive effect, leading to a profile of circulating inflammatory response similar in quantification of T1 and T2 on both groups. Furthermore, these results suggest that a number of interactions of CXCL-8, CXCL-9, CCL-2, IL-6, and IFN-γ in HF patients are directly affected by fibrinogen levels, which may be related to the inflammatory response and coagulation mutual relationship induced by B. atrox venom. The present study is the first report on inflammation-coagulation crosstalk involving snakebite patients and supports the better understanding of envenomation's pathophysiology mechanisms and guides in the search for novel biomarkers and prospective therapies.

Hemorrhagic stroke following viper bites and delayed antivenom administration: three case reports from the Western Brazilian Amazon.

Snakebites were included by the World Health Organization in their list of neglected diseases. In Latin America, most snakebites are caused by species of the Viperidae family, notably by the genus Bothrops. Bothrops atrox accounts for 90% of the cases of envenoming in the Brazilian Amazon. In this report, we present a series of three cases of snakebites that evolved with hemorrhagic stroke due to delays in the access to antivenom in the Brazilian Amazon, being fundamental for diagnosis to validate the clinical suspicion and make decisions that would improve the treatment and prognosis of the patients.

An Immunological Stairway to Severe Tissue Complication Assembly in Bothrops atrox Snakebites.

Snakebites are a serious public health problem and, in the Amazon, the Bothrops atrox snake is the most frequent cause of envenomation. B. atrox venom (BaV) causes pathophysiological changes with intense, local inflammatory processes, such as severe tissue complication (STC). However, mechanisms associated with the inflammatory process in humans are still poorly understood. Thus, in this study, we sought to describe the profile of local and systemic immunological soluble molecules in Bothrops envenomation patients treated at a specialist tertiary healthcare unit in the Brazilian Amazon. An analytical and prospective study was performed with patients who had snakebites with different clinical outcomes (STC and Mild Tissue Complication-MTC) using venous blood and blister exudate in order to measure immunological soluble molecules present in the response process. Twenty STC patients and 20 MTC patients were eligible for the study. In addition, 20 healthy donors (HD) who had never been bitten by a snake were used as controls. The biomarkers CXCL-8, CCL-5, CXCL-9, CCL-2 and CXCL-10; C3a, C4a, and C5a; IL-1, IL-2, IL-4, IL-5, IL-6, IL-10, TNF, IFN-γ and IL-17A were quantified using flow cytometry and ELISA. The circulating response profile differs between the studied groups, with MTC patients presenting a mixed profile and STC patients presenting a more polarized profile for Th1 response. In addition, individuals who develop STC have a more intense local immune response, because the tissue response differs from the circulating immunological soluble molecules and presents Th1/Th2/Th17 response polarization. Furthermore, these results suggest that CCL-2 and CXCL-10 are biomarkers for STC and the response profile they assume against Bothrops snakebite should reflect in the clinical practice for the patient.

Hymenoptera stings in Brazil: a neglected health threat in Amazonas State.

INTRODUCTION: Hymenoptera injuries are commonly caused by stinging insects. In Amazonas state, Brazil, there is no information regarding distribution, profile, and systemic manifestations associated with Hymenoptera injuries. METHODS: This study aimed to identify risk factors for systemic manifestation using the Brazilian Notifiable Diseases Surveillance System (2007 to 2015). RESULTS: Half of Hymenoptera injuries were caused by bee stings. Hymenoptera injuries were concentrated in Manaus, and 13.36% of cases displayed systemic signs. Delayed medical assistance (4 to 12 hours) presented four times more risk for systemic manifestations. CONCLUSIONS: Simple clinical observations and history of injury are critical information for prognostic improvement.

Accuracy of the Lee-White Clotting Time Performed in the Hospital Routine to Detect Coagulopathy in Bothrops atrox Envenomation.

Snake envenomation is a major public health problem in Brazil. Systemic complications that may arise from snakebites are mainly related to coagulopathy. The Lee-White clotting time (LWCT) is a simple and inexpensive test and available even in remote health facilities. However, the diagnostic value of such test needs to be evaluated to accurately diagnose coagulopathy in the clinical practice. This study aimed to assess the reliability of the LWCT performed in hospital routine to diagnose venom-induced coagulopathy. We studied 186 patients admitted at the Tropical Medicine Foundation Dr. Heitor Vieira Dourado in Manaus, Amazonas, Brazil, with Bothrops envenomation diagnosis. At admission, blood samples were collected for performing LWCT and the concentration of fibrinogen. Sensitivity, specificity, positive predictive value, negative predictive value, likelihood ratios, diagnostic odds ratio, and accuracy were calculated with 95% confidence intervals. From the total, 85.5% had hypofibrinogenemia. The sensitivity of the LWCT to the diagnosis of hypofibrinogenemia was 78.0% and the specificity 40.7%. The accuracy of the test was 72.6%, and patients with a prolonged LWCT had 2.4 higher odds of developing hypofibrinogenemia. In addition, the LWCT was also compared with venom antigen levels and systemic hemorrhage. The LWCT showed moderate sensitivity to detect consumption coagulopathy and constitutes a valuable tool for the diagnosis of Bothrops snake envenomation and indication of antivenom therapy.

Severe tissue complications in patients of Bothrops snakebite at a tertiary health unit in the Brazilian Amazon: clinical characteristics and associated factors

Abstract INTRODUCTION: Snakebites in the Brazilian Amazon are caused mostly by snakes from the Bothrops genus and envenomated patients may suffer from tissue complications. METHODS: This study aimed to identify risk factors for severe tissue complications (STC) in patients with Bothrops snakebite in the Amazonas state, Brazil. RESULTS: Snakebites that were classified as severe and affected female patients with comorbidities presented greater risks of developing STCs. In addition, hospitalizations of patients with STC exceeded 5 days. CONCLUSIONS: Clinical and epidemiological characteristics can prove essential for assessing the evolution of STC and clinical prognosis of patients with Bothrops snakebites.

Bee sting envenomation severe cases in Manaus, Brazilian Amazon: clinical characteristics and immune markers of case reports

Abstract Bee venom is a natural toxin composed of several peptides. Massive envenoming causes severe local and systemic reactions. We report two cases of severe bee envenomation, of which one was fatal. We also describe clinical characteristics and immune markers. Both victims suffered from respiratory distress, renal failure, rhabdomyolysis, and shock. They required invasive mechanical ventilation, vasoactive drugs, and renal replacement therapy. Moreover, serum levels of chemokines, cytokines, and cell-free circulating nucleic acids demonstrated an intense inflammatory process. Massive envenoming produced systemic injury in the victims, with an uncontrolled inflammatory response, and a more significant chemotactic response in the fatal case.

Hemorrhagic stroke following viper bites and delayed antivenom administration: three case reports from the Western Brazilian Amazon

Abstract Snakebites were included by the World Health Organization in their list of neglected diseases. In Latin America, most snakebites are caused by species of the Viperidae family, notably by the genus Bothrops. Bothrops atrox accounts for 90% of the cases of envenoming in the Brazilian Amazon. In this report, we present a series of three cases of snakebites that evolved with hemorrhagic stroke due to delays in the access to antivenom in the Brazilian Amazon, being fundamental for diagnosis to validate the clinical suspicion and make decisions that would improve the treatment and prognosis of the patients.

Hymenoptera stings in Brazil: a neglected health threat in Amazonas State

Abstract INTRODUCTION: Hymenoptera injuries are commonly caused by stinging insects. In Amazonas state, Brazil, there is no information regarding distribution, profile, and systemic manifestations associated with Hymenoptera injuries. METHODS: This study aimed to identify risk factors for systemic manifestation using the Brazilian Notifiable Diseases Surveillance System (2007 to 2015). RESULTS: Half of Hymenoptera injuries were caused by bee stings. Hymenoptera injuries were concentrated in Manaus, and 13.36% of cases displayed systemic signs. Delayed medical assistance (4 to 12 hours) presented four times more risk for systemic manifestations. CONCLUSIONS: Simple clinical observations and history of injury are critical information for prognostic improvement.