Sage Journals: Discover world-class research

Abstract

Introduction

The municipality of Barcelos, located in the middle Rio Negro region, is home to various venomous snakes (ie, members of the Viperidae and Elapidae families). This study describes the epidemiology of incidents involving venomous animals in the remote municipality of Barcelos.

Methods

We conducted a retrospective epidemiological study to identify population groups vulnerable to envenomation by snakes, spiders, and/or scorpions in the middle Rio Negro (Barcelos) basin, Amazonas, Brazil. To determine the percentage of incidents, we calculated the occurrence and number of deaths. Data were collected from the Barcelos Reference Hospital from 2010 to 2024. The type and number of antivenom vials used in the treatment of patients were quantified according to the Strategic Inputs Information System (SIES).

Results

A total of 511 people were envenomated by venomous animals, 402 of them by snakes. Yanomami individuals were the most affected by snakebites (62.4%). Envenomations by Bothrops spp. caused 7 deaths, while those caused by spiders and scorpions were mostly mild. Among the snakebite survivors, 38 had their occupations identified at the time of the incident: 25 worked in the extraction of piassaba fibers (Leopoldinia piassaba) and 13 were chestnut fruit collectors (Bertholletia excelsa).

Conclusion

Between 2010 and 2024, vulnerable groups to snakebites, such as Yanomami people, were the most affected in the middle Rio Negro region. Amerindians who sought medical care at the Barcelos referral hospital received antivenom treatment and intensive care when necessary. Emergency medical services and therapeutic serums are crucial to saving lives in the Rio Negro region.

Keywords

Barcelos venomous animals snakebites antivenom

Introduction

Venomous animal envenomation is a frequent occurrence in rural Amazon,^1–7 particularly among individuals who self-identify as brown or Indigenous.^6–10 These people are more prone to negative interactions with snakes, spiders, and scorpions.^6,7,10 Among venomous snakes, Bothrops atrox (commonly known as the lancehead) is responsible for the most serious cases of envenomation in the Amazon Basin.⁴^11–13 In addition, stings from clinically significant scorpions, such as Tityus obscurus, Tityus metuendus, and Tityus silvestris, often require medical intervention.^8–10^,14

In the Brazilian Amazon, data on incidents involving venomous animals are often recorded and analyzed at the state level.^6–10^,15–17 For example, in 2023, the state of Amazonas reported 1793 cases of snakebites, an incidence rate of 41.99 per 100,000 inhabitants, and a mortality rate of 0.78%, which exceeds the national average of 0.44%.¹⁵ The frequency and severity of envenomation by venomous animals are less well documented in Amazonian municipalities. In different rural regions of northern Brazil, moderate and severe cases of snake and scorpion envenomation are strongly linked to manual labor.^1,10,16

The municipality of Barcelos (0°56'08.8"S, 62°50'23.4"W), located on the middle Rio Negro in the state of Amazonas, Brazil, is home to several medically important snake species, such as B. atrox, B. brazili, and Lachesis muta, which pose an occupational risk to rural workers.¹ Many rural communities in the Barcelos region depend on subsistence activities, such as hunting, fishing, and extractivism, practices that increase their exposure to venomous animals.^1,12 Despite the high probability of encounters with these animals and the intensity of extractive activities in forests rich in venomous animals, epidemiological studies on the occurrence of snakebites, spider bites, and scorpion stings in Barcelos are still scarce.¹

This study describes the epidemiology of incidents by venomous animals in Barcelos between 2010 and 2024. Retrospective data were obtained from the care records of the Barcelos General Hospital and the Strategic Inputs Information System (SIES) to estimate the use of antivenoms. The analysis includes annual averages of cases, incidence rates, deaths, the monthly distribution of cases, and risk factors that contribute to exposure to venomous animals such as snakes, scorpions, and spiders.

Methods

Study Area and Population

Barcelos (0°58'17.5"S, 62°47'15.3"W) is the largest municipality by area in the state of Amazonas, Brazil, located in the middle Rio Negro region (Figure 1A).^18–21 The river distance between Manaus, the capital of Amazonas, and Barcelos is approximately 530 km,²² a journey that takes, on average, 35 h by commercial boat.²³

Figure 1.

Map of Brazil highlighting the state of Amazonas. (A) Location of the municipality of Barcelos, in the north of the state; (B) View of the river port of Barcelos. The large number of different vessels reveals the local people’s dependence on water transport. Photos by Jonas Martins (B).

The municipality holds historical importance, since it was the first capital of the former province of Amazonas.¹⁹ Currently, Barcelos has a population of around 18,834 inhabitants.²³ The local tropical climate features temperatures ranging from 20 °C to 38 °C and average annual rainfall of 2286 mm.¹⁹ With regard to the ethnic composition of Barcelos’s population, 32.5% identify themselves as Indigenous, predominantly of the Yanomami ethnic group; 52.8% as mixed race; 9.8% as white; and 4% as Black.²⁰ The non-Indigenous population mainly descends from families who migrated from Brazil's Northeast region in search of employment opportunities. ^24,²⁵

Social and Economic Aspects

In the division of labor, many families in Barcelos have practices similar to those of other riverside groups, where women dedicate themselves to domestic chores and childcare^19,22,24 and men are involved in agricultural tasks.²⁴ The rivers and forests of the middle Rio Negro provide natural resources that support different forms of subsistence in the region.^22,25

The main economic activities in Barcelos are fishing, plant extraction, and tourism.²⁶ The municipality faces significant socioeconomic problems. Recent data show that 2837 families live in extreme poverty.²⁵ Unemployment affects several riverside families, who depend on revenue from the extraction of natural products, such as piassaba fibers (Leopoldinia piassaba), for sustenance.^{19,21,22,24,25}

Data Collection

We carried out a retrospective epidemiological survey of bites/stings by venomous animals recorded at the General Hospital of Barcelos (0°58'18.6"S 62°41'51.2"W), a medium-complexity health center in the urban area of the municipality,²⁶ from 2010 to 2024. The incident data came from the Notifiable Diseases Information System (SINAN) files stored in the municipality's health surveillance department. Furthermore, the frequency of antivenom use during the study period was obtained through the Strategic Inputs Information System (SIES), a platform linked to the Brazilian Ministry of Health that consolidates information from state health departments on the allocation and use of immunobiological drugs distributed throughout the country.²⁷

Analysis

Microdata were grouped in Microsoft Excel^® (version 2016). Univariate statistics were calculated by age group, gender, and race (self-reported) to describe the groups affected by venomous animals. We used local incident data to estimate the fatality rate and incidence rate per 100,000 population. We also analyzed the risks of snake, spider, and scorpion envenomation among Indigenous and non-Indigenous people.

Results

Between 2010 and 2024, Barcelos General Hospital treated 511 patients with symptoms of envenoming by venomous animals. Of these cases, 402 (78.7%) were due to snakebites, 86 (16.8%) to scorpion stings, and 23 (4.5%) to spider bites. Snakebites mainly affected the Yanomami people, totaling 319 cases (62.4%) (Table 1). Among the total number of victims, 174 were illiterate and 136 had not completed formal primary education.

Table 1.

Characteristics of the 511 Envenomations by Venomous Animals in Barcelos, Amazonas, Brazil, from 2010 to 2024.

Gender	Number	Total
Male	363	71.8%
Female	142	28.1%
Area of occurrence
Rural	316	62.58%
Urban	170	33.3%
Periurban	25	4.1%
Work-related accident
Yes	234	55.4%
No	188	44.5%
Ethnicity
Yanomami	319	62.4%
Non-Yanomami	192	37.6%
Occupational risk
Brazil nut collector	13	2.5%
Piaçabeiro	25	4.9%
Type of envenomings
Snake	402	78.7%
Scorpion	86	16.8%
Spider	23	4.5%
Time from bite/sting to medical assistance (in hours)
< 1	169	33.1%
1–3	92	18%
3–6	62	12.1%
6–12	67	13.1%
12–24	42	8.2%
>24	76	14.8%
Bite/sting site
Head	16	3.1%
Upper limbs	56	10.9%
Lower limbs	439	86%
Severity classification
Mild	266	71.8%
Moderate	105	22.1%
Severe	31	6.1%
Type of antivenom used
SAB	1.239	82.5%
SABL	178	11.8%
SABC	33	2.2%
SAE	20	1.3%
SAESC	28	1.8%
SAAR	8	0.5%

Acronyms indicate antivenom types: SAB (Bothrops spp.), SABL (Bothrops/Lachesis), SABC (Bothrops/Crotalus), SAE (Micrurus spp.), SAESC (Tityus sp.), and SAAR (Phoneutria, Loxosceles and Tityus).

In the Barcelos region, the incidence peaked in 2019 (398.2 cases per 100,000 inhabitants). Most envenomation cases occurred in rural areas (62.58%) during the rainy season (January to May). The number of incidents increased between 2018 and 2020 and then decreased in the following years. Patients envenomated by scorpions and spiders presented predominantly mild symptoms, with 58 and 20 cases reported, respectively. In turn, the severity of snakebites varied: 53.8% (n = 266) were mild, 26.1% (n = 105) were moderate, and 7.7% (n = 31) were severe. Most cases of snake, spider, and scorpion envenomation were treated at the Barcelos reference unit without prior identification of the species that caused the symptoms. In the SINAN forms examined, most snakebites were attributed to the genus Bothrops spp. (n = 384), followed by Lachesis sp. (n = 13) and Micrurus spp. (n = 5) (Figure 2). Only snakebites resulted in death (n = 7; fatality rate of 1.7%) (Table 1).

Figure 2.

Venomous animals found in the middle Rio Negro region, Amazonas, Brazil. (A) Lachesis muta; (B) Bothrops atrox; (C) A Micrurus surinamensis found and killed by a resident in the Santo Antônio neighborhood (0°56'34.9"S 62°57'05.7"W), Barcelos; (D) Phoneutria fera; (D) Tityus sylviae; (F) a 54-year-old piassaba worker with a positive history of snakebites on the left leg (yellow circle); (G) the same man survived envenomation by a wandering spider (Phoneutria spp.) on the hand (white circle); (H) amputation of the distal phalanx of the left little finger (white circle) resulting from potential Bothrops spp. envenomation suffered while handling piassaba fiber. Photos by Serra Grande Snake Farm (A), Breno Almeida (B), Terezinha Marat (C), Jonas Martins (D–H).

In the middle Rio Negro region, most cases of envenoming by venomous animals occurred during agricultural activities. There was little information about the activity performed at the time of the incident. Among the occupations identified, 25 snakebites occurred during the extraction of piassaba fibers (Figure 3), while 13 cases happened during the collection of Brazil nuts (Bertholletia excelsa). Among the different types of antivenom administered at the Barcelos referral unit, the most commonly used was bothropic antivenom (SAB). Over a 14-year period, a total of 1470 vials were administered for snakebites, 28 for scorpion stings, and 8 for spider bites (Table 1).

Figure 3.

Leopoldinia piassaba found in the rural area of Barcelos (A); natural fibers covering the entire stem of the palm tree, where spiders, scorpions, and snakes often hide (B); boat in the port of Barcelos with piassaba fibers extracted in the region of the Rio Aracá (C). In the municipality, the fibers are sold for the manufacture of brooms, bags, and baskets. Photos by Jonas Martins (A–C).

Discussion

Bothrops atrox envenomation has historically been a significant public health problem in Amazonas.^1,17,31 Victims require immediate medical attention to prevent the venom's fatal pathophysiological effects.^1–4 It is estimated that over 80% of snakebites in the Brazilian Amazon are caused by B. atrox (Figure 2B).³¹ In Barcelos, antivenom against Bothrops spp. venom (SAB) was the most used in the reference hospital (1239 vials administered, representing 82.3% of the total) (Table 1).

Envenomation by “surucucu-pico-de-jaca” (Lachesis muta) (Figure 2A) is less frequent in Barcelos (n = 13), as in other regions of the Amazon.^7,15^28–30 Lachesis muta has venom with proteolytic, coagulant, hemorrhagic, and neurotoxic activities.^7,29,30 The myonecrosis and hemorrhage caused by these venoms can lead health professionals to wrongly classify the incident as caused by Bothrops spp.³¹

A significant clinical difference between the symptoms of L. muta and B. atrox envenomation is the occurrence of vagal syndrome.⁷ In cases of doubt about the responsible animal, bivalent antivenom (SABL) is effective in neutralizing the toxins of the genera Bothrops and Lachesis.³² Although there are no reports of species of the genus Crotalus spp. in the middle Rio Negro region, 33 vials specific for Bothrops/Crotalus were used; this type of immunobiological treatment also has activity against Bothrops spp.,³² which may have motivated its application. The antielapidic serum (SAE) against Micrurus spp. (Figure 2C) envenomation was the least used in Barcelos (Table 1). However, species of this genus are frequently found in the forest areas of rural neighborhoods in Barcelos (Figure 2C).

Official data on incidents with venomous animals in the middle Rio Negro region reveal that snakebites are the most frequent cause. Among 402 reported snakebite cases (Table 1), 7 resulted in death, corresponding to a fatality rate of 1.7%. Snakebite cases were asymmetrically prevalent among the Yanomami (Table 1). One fatal case involved a 64-year-old Indigenous woman in 2022, residing in the Moura district (1°27'21.8"S 61°38'02.4"W) (Figure 4A), who was bitten inside her home by a lancehead pitviper (Bothrops spp.) Under the effects of envenoming and accompanied by a nurse, the victim traveled approximately 145 km by river to the municipal hospital, receiving 5 vials of SAB (bothropic antivenom) along the way. Upon admission, the patient was diagnosed with systemic symptoms and was given 7 more vials, but she did not survive (data from the SINAN archive).

Figure 4.

(A) Moura District (1°27'25.2"S 61°38'02.9"W), Barcelos, where a 62-year-old resident was bitten inside her home by a Bothrops spp. and did not survive; (B) Indigenous housing in the Santo Antônio neighborhood (0°56'36.1"S 62°57'07.7"W), Barcelos. The red arrows point to a Yanomami family on the banks of the Rio Negro and the houses where they stay when they come from their distant rural communities; (C) canoes used by riverside dwellers in the community of Piloto (0°47'47.5"S 63°07'49.5"W), Barcelos. These canoes are generally used by impoverished people in the Amazon; (D) commercial boat used to transport batches of antivenom from Manaus to Barcelos (0°58'56.5"S 62°52'34.1"W) and Santa Isabel do Rio Negro (0°24'53.8"S 65°00'55.2"W), Amazonas, Brazil. Photos by Jonas Martins (A–C) and Lirio Reis (D).

Piaçabeiros in the Rio Negro region have a positive history of snake and spider envenomation (Figure 2FH). In the Barcelos region, manual extraction of piassaba fibers (L. piassaba) (Figure 3) was associated with 25 snakebite cases. Additionally, 13 chestnut (Bertholletia excelsa) fruit collectors were envenomed while working. Natural fibers and chestnut fruits are important sources of income for riverside residents, who sell these products in Barcelos (Figure 3C).^18,21,24,33 Effective management practices, including mapping high-risk areas for encounters with venomous animals and guidance on the use of personal protective equipment, are essential to optimize working conditions and minimize the risk of envenomation by snakes, spiders, and scorpions hiding in L. piassaba fibers.⁴

Snakebites Suffered by Yanomami People

Historical reports of negative interactions between Amerindians and venomous snakes in the Amazon rainforest are not recent. In fact, Alfred Russel Wallace, in his travels through the Rio Negro region in the 19^th century, recorded fatal incidents involving Indigenous people.³³ Recent anthropological research among the Yanomami population in the Rio Orinoco region of Venezuela indicates that envenomation by B. atrox is responsible for approximately 2% of adult deaths.¹² Yanomami groups in the Brazilian Amazon call local venomous snakes “karihirimakɨ” for Bothrops spp. and “preerimakɨ” for bushmasters (Lachesis spp.).⁵

Yanomami communities affected by snakebites are in the Rio Negro region and are located along the banks of rivers such as the Xié, Demeni, and Marié (Figure 4B).^18,23 Herpetological data such as the composition of venomous snakes in these remote regions of the Amazon are relatively scarce in the literature.³⁴ In addition to Barcelos, the territory of these Amerindians is extensive, reaching the tributaries of the right bank of the Rio Branco, in the state of Roraima (3°37'44.9"N 61°08'11.9"W).²³

A total of 319 (62.4%) people of the Yanomami ethnic group were envenomed by snakes (Table 1). Although the fatality rate for snake envenomation in the middle Rio Negro region (1.7%) is higher than the national average (0.44% in 2023),¹⁵ most of the cases were mild and responded well to serum therapy. A brief tally of social factors in the Rio Negro region indicates the risk of incidents involving venomous animals (Table 1).

Members of the Yanomami communities (Figure 4B) of the Rio Negro region may be affected by species such as Bothriopsis taeniata (Viperidae), which produces a venom with more intense hemorrhagic activity than B. atrox.³¹ In addition to B. atrox and B. taeniata, the green viper B. bilineatus, known as the “cobra-papagaio” in Amazonas, Brazil, is also a source of concern in many Indigenous and non-Indigenous territories.^2,35 Its natural color makes it difficult to detect in vegetation, and riverside people often only notice its presence after being bitten.²

Yanomami Risk Behavior

The Yanomami (Figure 4B) rely heavily on hunting and small-scale agriculture for their subsistence, thus maintaining a close relationship with the forests for food sources.^5,12,13 However, this subsistence routine involves significant risks. For example, the transport of cassava (Manihot esculenta) by members of the Rio Tiquié Indigenous community (Amazonas state, Brazil) is done barefoot along forest trails,³⁶ which increases their exposure to venomous animals hidden in the leaf litter.¹³ Furthermore, nighttime hunting by Amerindians spatially overlaps the activity of snakes such as B. atrox (Figure 2B), which are more active at night, increasing the likelihood of encounters between people and venomous animals.

Risky behaviors have been reported among Yanomami communities in the Rio Mariuá region of Amazonas, who tend to leave their permanent villages, areas with a lower risk of envenomation involving venomous animals, to establish temporary camps in the forest during periods of food scarcity.³⁸ In the forest, Indigenous children and adults who explore burrows in the leaf litter and natural hiding places in the vegetation with their hands in search of animals to supplement their diet are exposed to the risk of being bitten by young lanceheads, commonly found in trees.³⁷

Indigenous people from the Rio Negro region who work in plant extraction migrate seasonally to forest areas with high concentrations of L. piassaba.^21,35 Following an “extractive calendar,” they begin collecting fibers and “cipó-titica” (Heteropsis flexuosa Kunth) between December and March.²¹ This period of activity coincides with an increase in the number of encounters with lanceheads (jararaca/Bothrops) in the forests of the Central Amazonian region (Manaus).³⁷

Snakebites occur not only in forests inhabited by native populations but can also occur within the homes of Indigenous people in the Rio Negro region. For example, an elderly Indigenous woman living in the middle Rio Negro region was bitten by a lancehead while organizing her clothes (data from the SINAN archive).

The Indigenous people's preference for medical treatment at the Barcelos referral hospital may be related to the infrastructure of the Special Indigenous Health Districts (DSEI), some of which lack the constant presence of doctors and have palm-leaf roofs and wooden walls.³⁸ Furthermore, in the middle Rio Negro region, the Barcelos hospital is, to our knowledge, the only facility offering intensive care for severely envenomed patients. Adequate emergency medical services contribute to the reputation of a referral unit and encourage vulnerable people living far away to seek care at municipal centers, thus contributing to the epidemiological surveillance of venomous animal envenomation.

Recommendations and Strategies to Reduce Serious Snake Envenomation in the middle Rio Negro

It is essential to conduct clinical and epidemiological studies to analyze the symptoms and frequency of cases involving venomous animals in the middle Rio Negro region, where such data are scarce. Future research should include interviews with rural community members, aiming to understand their way of life, the causes of incidents, and the challenges faced in accessing health services.

Comprehensive herpetological inventories and taxonomic studies of medically important venomous animals in the Rio Negro basin are research priorities, particularly for species of the genus Bothrops, which are responsible for most serious snakebites in the Amazon region. Given the considerable severity of snakebites in Barcelos, reflected in a 1.7% mortality rate, targeted snakebite prevention campaigns should be implemented to raise awareness of risk factors in local communities.

Since the extraction of piassaba fibers and other nontimber products such as “cipó-titica” (Heteropsis flexuosa Kunth) is not mechanized, awareness campaigns should provide guidance on the use of personal protective equipment to reduce the chance of bites/stings by venomous animals.

Healthcare professionals working in remote areas of the Amazon should receive training at tertiary hospitals on the different types of envenomation that occur in the Amazon. Professionals should be informed, for example, that although bites from Dipsadidae snakes are less clinically significant than those from Viperidae species, they can induce mild to moderate local symptoms, including pain, swelling, and bruising. Distinguishing between incidents involving Dipsadidae and Viperidae is necessary to reduce unnecessary antivenom administration.

The Rio Negro Basin has approximately 700 tributaries and a wide spatial dispersion of rural communities. Thus, boats providing healthcare to riverside communities with therapeutic units may be strategically necessary in navigable stretches of the Rio Negro, ensuring more timely care, especially in areas where health services are lacking.

Strengths and Limitations

This study documents the burden of venomous animal incidents in Barcelos, a remote municipality in the state of Amazonas, where conducting scientific research faces substantial logistical and operational challenges. The results identify the Yanomami Indigenous population of the middle Rio Negro as a group particularly vulnerable to snakebites in the region. Although these Amerindians have been extensively studied by anthropologists, venomous animal incidents among them lack clinical toxinology studies.

Our analysis of incident records from the Barcelos referral unit indicates that most therapeutic treatments administered were presumptive. The choice of antivenom in many snakebite cases was not based on formal identification of the snake. The genus Bothrops was recorded as the primary cause of envenomation in incident reports. Healthcare professionals should be aware that errors in identifying the responsible animals can have serious consequences for patients, future evidence-based clinical management, and the conservation of the snakes themselves. If formal identification is not established using minimally acceptable taxonomic criteria, the species cannot be considered “verified” or “confirmed.” Instead, by definition the classification would be “presumed.”

This limitation makes it difficult for healthcare professionals to predict prognosis and implement specific therapeutic strategies for each responsible species. Although serious snakebites occurred during the study period, the available clinical records did not document the physical consequences of envenomation, such as lesions on the hands and feet, which can directly affect the lifestyle of rural community members.

Researchers intending to use clinical data from SINAN forms in epidemiological studies should be aware of some limitations in official records, such as: (i) the forms lack a specific field for recording comorbidities of envenoming victims and (ii) detailed information on severe envenomings is limited or only partially complete. The clinical data section of the forms prioritizes fields related to systemic manifestations and blood clotting time.

Future studies focusing on venomous animal incidents in the middle Rio Negro region are a priority, particularly those involving snakes, scorpions, and spiders affecting the Yanomami indigenous population and other vulnerable rural communities. Such investigations should integrate comprehensive epidemiological data, systematic identification of responsible species, detailed clinical profiles of victims including documentation of physical sequelae, and rigorous assessment of therapeutic intervention's effectiveness.

Conclusions

In the municipality of Barcelos, cases involving snakes exceed those caused by other medically important animals, such as spiders and scorpions. According to local epidemiological data, most cases of envenomation and deaths were caused by species of the genus Bothrops. The fatality rate of snakebites was estimated at 1.7%, a figure that exceeds the national average of 0.44% recorded in 2023 by the Brazilian Ministry of Health.

Healthcare facilities serving as referral centers in the Brazilian Amazon region should systematically question victims about preexisting comorbidities and any self-care measures or traditional remedies applied to the bite/sting site. This comprehensive patient assessment is essential to enable healthcare professionals to identify potential complications, recognize contraindications to standard antivenom therapy, and develop individualized therapeutic management plans that optimize clinical outcomes and minimize adverse effects.

To address this scenario, regular distribution of antivenom in the middle Rio Negro region is essential, in addition to the local expansion of emergency services, focusing on areas at high risk of bites/stings from animals such as snakes and scorpions. This can ensure that rural populations exposed to venomous animals have access to adequate and timely care.

Footnotes

Abbreviations

Acknowledgments

We thank the healthcare professionals at Barcelos General Hospital, especially Dra. Patrícia Leite, municipal health secretary, and Gabriel Marinho Soares (SEMSA/Barcelos), for their assistance in accessing the notification forms for incidents involving venomous animals. We also express our gratitude to Flávio Dourado of the Brazilian Ministry of Health for compiling the data on the use of antivenoms in Barcelos on the SIES website.

ORCID iDs

Jonas Gama Martins

Lirio Diogo da Silva Reis

Lourena Braga Pereira

Saymom Miller Fernandes Soares

Lourayne Braga Pereira

Luan Felipe da Silva Frade

Bruno Rafael Ribeiro de Almeida

Pedro Pereira de Oliveira Pardal

Rudi Emerson de Lima Procópio

Author Contribution(s)

Jonas Gama Martins: Conceptualization; Investigation; Methodology; Writing - review & editing.

Lirio Diogo da Silva Reis: Investigation.

Lourena Braga Pereira: Investigation; Resources; Software.

Saymom Miller Fernandes Soares: Investigation.

Lourrayne Braga Pereira: Investigation; Resources; Software.

Luan Felipe da Silva Frade: Formal analysis; Software;Supervision.

Bruno Rafael Ribeiro de Almeira: Investigation; Resources.

Pedro Pereira de Oliveira Pardal: Review.

Rudi Emerson de Lima Procópio: Formal analysis; Resources; Review.

Funding

This study was supported by the Amazonas State Research Support Foundation (FAPEAM- POSGRAD 353/2023).

Declaration of Conflicting Interests

The authors declare no conflicts of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.

References

Borges

Sadihiro

dos Santos

. Epidemiological and clinical aspects of snake accidents in the municipalities of the State of Amazonas, Brazil. Rev Soc Bras Med Trop. 1999;32(6):37-646.

Waldez

Vogt

. Ecological and epidemiological aspects of snakebites in riverside communities of the lower Purus River, Amazonas, Brazil. Acta Amaz. 2009;39(3):681-92.

López-Lozano

de Sousa

Ricart

, et al. Ontogenetic variation of metalloproteinases and plasma coagulant activity in venoms of wild Bothrops atrox specimens from Amazonian rain forest. Toxicon. 2002;40(7):997-1006.

Núñez

Cid

Sanz

, et al. Snake venomics and antivenomics of Bothrops atrox venoms from Colombia and the Amazon regions of Brazil, Perú and Ecuador suggest the occurrence of geographic variation of venom phenotype by a trend towards paedomorphism. J Proteomics. 2009;73(1):57-78.

Albert

Gomez

. Saúde Yanomami: um manual etnolingüistico. Belém: Museu Paraense Emilio Goeldi [internet] 1997. Accessed: December 27, 2024. https://horizon.documentation.ird.fr/exl-doc/pleins_textes/divers14-09/010021801.pdf.

Pardal

PPO

Santo

PRSG

Cardoso

Lima

Gadelha

. Spatial distribution of envenomation by scorpions in Pará state, Brazil. Rev Patol Trop. 2017;46(1):94-104. doi:10.5216/rpt.v46i1.46296

Pardal

PPO

Souza

Monteiro

MRCC

, et al. Clinical trial of two antivenoms for the treatment of Bothrops and Lachesis bites in the north eastern Amazon region of Brazil. Trans R Soc Trop Med Hyg. 2004;98(1):28–42.

Martins

Pardal

PPO

Brescovit

Procópio

REL

. An overview of spider accidents in the Brazilian Amazon. J Venom Anim Toxins Incl Trop Dis. 2025;11(31):e20240057.

Martins

Reis

Zuanazzi

Bordon

KCF

Zoccal

Procópio

. Clinical outcomes in a murine model after envenoming by the Amazonian scorpions Tityus strandi and Tityus dinizi. Toxicon. 2024;246(2):107797.

10.

Martins

Bordon

KCF

Moreno-González

, et al. On the noxious black Amazonian scorpion, Tityus obscurus (Scorpiones, Buthidae): Taxonomic notes, biology, medical importance and envenoming treatment. Toxicon. 2023;228(1):107125.

11.

Calvete

Sanz

Pérez

, et al. Snake population venomics and antivenomics of Bothrops atrox: Paedomorphism along its transamazonian dispersal and implications of geographic venom variability on snakebite management. J Proteomics. 2011;74(4):510-27.

12.

Chagnon NA. Yanomamö: the fierce people. Case studies in current anthropology. 1nd. In: George R, Spindler L, eds. Holt McDougal; 1968.

13.

Chagnon

. Nobres selvagens: minha vida entre duas tribos perigosas: os ianomâmis e os antropólogos. Três Estrelas; 2014.

14.

Reis

Martins

Bordon

KCF

, et al. Pioneering in vitro characterization of macrophage response induced by scorpion venoms from the Brazilian Amazon. Toxicon. 2023;230(7):107171.

15.

Brasil, Ministério da Saúde/SVS. Epidemiologia dos acidentes ofídicos no Brasil [internet] 2023. Accessed: Jan. 15, 2025. https://www.gov.br/saude/pt-br/centrais-de-conteudo/publicacoes/boletins/epidemiologicos/edicoes/2024/boletim-epidemiologico-volume-55-no-15.pdf.

16.

Feitosa

Mise

Mota

ELA

. Snakebite in Tocantins: ecological analysis of determinants and risk areas, 2007–2015. Epidemiol Serv Saúde. 2020;29(4):4–e2020033. doi:10.5123/S1679-49742020000400016

17.

Chippaux

. Epidemiology of envenomations by terrestrial venomous animals in Brazil based on case reporting: from obvious facts to contingencies. J Venom Anim Toxins Incl Trop Dis. 2015;1321(5):13. doi:10.1186/s40409-015-0011-1

18.

Sobral

Dias

. Barcelos indígenas e ribeirinha: um perfil socioambiental. ISA/ASIBA/FOIRN; 2013.

19.

Suárez-Mutis

Coura

. Changes in the epidemiological pattern of malaria in a rural area of the middle Rio Negro, Brazilian Amazon: a retrospective analysis. Cad Saúde Pública. 2007;23(4):795-804.

20.

Duncan

Malheiro

Danilow

. Piassaba palm extractivism as an associated factor with Chagas disease: seroprevalence and immunological profile in native inhabitants of the Central Amazonia, Brazil. Rev Pan-Amaz Saude. 2015;6(3):35-42. doi:10.5123/S2176-62232015000300005

21.

Josa

. Piaçabeiros e piaçaba no Médio Rio Negro (Amazonas, Brasil), socioeconomia da atividade extrativista e ecologia da Leopoldinia piassaba Wallace [dissertation]. Universidade Federal do Estado do Amazonas; 2008. Accessed January 23, 2025. https://repositorio.inpa.gov.br/handle/1/5281.

22.

Instituto Brasileiro de Geografia e Estatística. Demographic cense [Internet] 2025. Accessed Jan. 14, 2025: https://cidades.ibge.gov.br/brasil/am/barcelos/panorama.

23.

Cabalzar

Ricardo

. Povos indígenas do Alto e Médio Rio Negro: uma introdução à diversidade cultural e ambiental do Noroeste da Amazônia brasileira. FOIRN/ISA; 1998.

24.

Benchimol

. Amazônia formação social e cultural Manaus. Maciel I, editor. Editora da Universidade do Amazonas. Manaus; 1999.

25.

Secretaria de Estado de Assistência Social do Estado do Amazonas. Boletim informativo socioecônomico do município de Barcelos [internet] 2024. Accessed December 29. https://www.seas.am.gov.br/wp-content/uploads/2021/08/BARCELOS.pdf.

26.

Cadastro Nacional de Estabelecimento de Saúde [Internet] 2023. Accessed March 14, 2025. http://cnes2.datasus.gov.br/Exibe_Ficha_Estabelecimento.asp?VCo_Unidade=1300402015242&VListar=1&VEstado=13&VMun=130040.

27.

Sistema de Informação de Insumos Estratégicos [Internet] 2024. Accessed April 12, 2025. http://sies.saude.gov.br/senha.asp.

28.

Adis

Mesquita

. Vertical distribution and abundance of arthropods in the soil of a neotropical secondary forest during the rainy season. Stud Neotrop Fauna Environ. 1987;4(8):22.

29.

Diniz-Sousa

Moraes

da Silva

TMR

Oliveira

Caldeira

CAS

. A brief review on the natural history, venomics and the medical importance of bushmaster (Lachesis) pitviper snakes. Toxicon. 2020;6(7):100053. doi:10.1016/j.toxcx.2020.100053

30.

Barrio-Amorós

Corrales

Rodríguez

Culebras

Dwyer

Flores

. The bushmasters (Lachesis spp.): queens of the rainforest. An overview of the taxonomy, distribution, natural history, lore, and conservation of the largest vipers in the world. Reptiles Amphib. 2020;27(3):358-81.

31.

Furtado

Cardoso

Soares

, et al. Antigenic cross-reactivity and immunogenicity of Bothrops venoms from snakes of the Amazon region. Toxicon. 2010;55(4):881-7.

32.

Fan

Vigilato

MAN

Pompei

JCA

Gutierrez

. Situacion de los laboratorios publicos productores de antivenenos en America Latina. Rev Panam Salud Publica. 2019;10(19):43.

33.

Wallace

. Palm Trees of the Amazon and Their Uses. John Van Voorst; 1853.

34.

Menin

Carvalho

Almeida

, et al. Amphibians from Santa Isabel do Rio Negro, Brazilian Amazonia. Phyllomedusa: J Herpetol. 1997;7(16):183-95.

35.

Bernarde

. Serpentes peçonhentas e acidentes ofídicos no Brasil. Anolis Books; 2014.

36.

Ricardo

Antongiovanni

. Visões do Rio Negro: construindo uma rede socioambiental na maior bacia de águas pretas do mundo. Instituto Socioambiental; 2008.

37.

Martins

Oliveira

. Natural history of snakes in forests of the Manaus region, Central Amazonia, Brazil. Herpetol Nat Hist. 1998;6(2):78-150.

38.

Gonçalves

LDV

Sousa

Lutaif

. Covid-19 na Terra Indígena Yanomami: um paralelo entre as regiões do alto rio Marauiá, alto Rio Negro e vale dos rios Ajarani e Apiaú. Mundo Amazónico. 2020;11(2):211-22.

Epidemiology of Envenomings by Venomous Animals in the Municipality of Barcelos (middle Rio Negro),Amazonas,Brazil

Abstract

Introduction

Methods

Results

Conclusion

Keywords

Introduction

Methods

Study Area and Population

Social and Economic Aspects

Data Collection

Analysis

Results

Discussion

Snakebites Suffered by Yanomami People

Yanomami Risk Behavior

Recommendations and Strategies to Reduce Serious Snake Envenomation in the middle Rio Negro

Strengths and Limitations

Conclusions

Footnotes

Abbreviations

Acknowledgments

ORCID iDs

Author Contribution(s)

Funding

Declaration of Conflicting Interests

References