Introduction

The Amazon Rainforest is recognized as the largest remaining tropical forest on Earth. However, this biome faces serious threats from deforestation, illegal fires, and the intensifying extreme climatic events [1,2]. The forest spans nine countries in South America; Brazil contains 60% of its total area, equivalent to 49% of Brazil’s territory [3]. In these regions, approximately 951,867.24 riverine people live along the banks of Amazonian rivers and their tributaries [4]. These communities built their livelihoods on these rivers, developing a deep connection to the natural environment through the use of the forest and river resources [5].

Amazonian rivers serve as the main routes for transportation and subsistence and help shape the cultural identity of local populations [5,6]. In the state of Amazonas, the Solimões River is especially important. Originating in Peru, it crosses into Brazil at Tabatinga and flows approximately 1,600 km before merging with the Rio Negro to form the Amazon River, which empties into the Atlantic Ocean [7]. Along its course, the Solimões River is divided into Alto (Upper), Médio (Middle), and Baixo (Lower) Solimões regions. The Upper Solimões region serves as an economic hub, encompassing Tabatinga (Brazil), Leticia (Colombia), and Santa Rosa (Peru), a district in the province of Mariscal Ramón Castilla. Tabatinga and Leticia form a transboundary hub characterized by commercial, cultural, and social exchanges [8].

In recent years, Amazonas has experienced severe droughts driven by rising temperatures, deforestation, fires, and an intensifying El Niño phenomenon, further aggravated by human activities [2,9–11]. In this context, Indigenous peoples, and Quilombolas are most affected, routinely contending with geographic isolation, food insecurity, and water scarcity [12]. The droughts have severely disrupted river transportation, a critical means of accessing food, goods, healthcare and other essential services [13]. Moreover, this situation has heightened the geographic isolation of certain communities, significantly extending response times for health emergencies and exposing lives to greater risks, particularly for those requiring continuous care [11]. A study highlighted the challenges riverine populations face in accessing healthcare: they travel an average of 60.4 km and take approximately 4.2 hours to reach urban centers with available services [14]. These findings illustrate how the distance and difficulties faced by these communities could be further intensified by the worsening global climate crisis [15]. Although existing research has effectively quantified transportation barriers and travel times, significant gaps remain in understanding how local residents perceive and respond to the climate-mediated health risks associated with increasingly frequent droughts and floods. The growing body of literature on health-seeking behaviors among vulnerable populations, including studies employing the Health Belief Model (HBM) to examine risk perception and care accessibility, demonstrates how environmental stressors amplify health disparities [16]. Within Amazonian contexts specifically, studies have revealed the role of cultural frameworks in shaping risk interpretation and response strategies in healthcare [17–19]. Thus, this study aimed to document how seasonal droughts and floods affect healthcare-seeking behaviors and understand residents’ perceptions of climate change over the last years. This provides unique qualitative insights and fills a critical gap in understanding health disparities in remote Amazonian communities.

Materials and methods

Study area and population

The study was conducted in a riverine community in Tabatinga, a city in the far west of Amazonas State, Brazil, within the Alto Solimões region (Fig 1).

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Fig 1. Area of study.

A: Tributary of the Solimões River during the Amazonian winter; B: Tributary of the Solimões River at the beginning of the dry season; C: Tributary of the Solimões River during the Amazonian dry season. The base used to create the map is from the IBGE (Brazilian Institute of Geography and Statistics), which is freely accessible for creative uses in shapefile format, following the Brazilian Access to Information Law (12,527/2011) [21].

https://doi.org/10.1371/journal.pone.0333408.g001

Over the past few years, the Alto Solimões region has faced severe droughts threatening its rich biodiversity and the cultures of diverse peoples. These communities face significant challenges in accessing basic services essential for well-being, such as healthcare, perpetuating social inequalities [22,23]. The tri-border location where Brazil, Colombia, and Peru meet increases challenges in accessing healthcare services. These issues arise from population movement across borders, communication difficulties between the countries’ healthcare systems, and criminal activity. This situation reinforces cycles of poverty and social inequality, with an infant mortality rate higher than the Brazilian national average.

The riverine community in this study, like many in the Brazilian Amazon, experiences marked seasonality, alternating between two distinct periods known as the Amazonian winter and summer. The Amazonian winter begins in mid-October and lasts for approximately eight months, characterized by torrential rains and rising river levels. During this period, boats serve as the primary mode of transportation used for agricultural and fishing activities, education, healthcare, and public safety. In contrast, during the Amazonian summer, as river levels recede, boats are largely replaced by motorcycles, off-road vehicles, and walking. This period intensifies geographic isolation, affecting numerous riverine communities along the Solimões River.

The study included individuals aged 12 years or older who were permanent residents of the riverine community and engaged in subsistence activities (small-scale farming, fishing, or hunting) that are directly affected by extreme climate events and voluntarily agreed to participate were eligible. The minimum age of 12 years was selected based on two criteria: (1) this marks the developmental stage when children begin participating meaningfully in family subsistence activities, and (2) younger children typically do not engage in these livelihood practices to the same extent. No participants withdrew consent during the study. Individuals under 12 were not included because the interviews and group discussions required communicative abilities typically found in participants aged 12 years and older. Participants were recruited through purposive sampling, and the principle of theoretical saturation [24] guided data collection, ensuring clear patterns emerged across interviews and discussions.

Data collection

In-depth individual interviews (IDIs) and focus group discussions (FGDs) were held between June and December 2022 using a semi-structured interview guide. This guide, developed by the research team, included open-ended questions, allowing the interviewer to explore topics in greater depth as needed (Table 1). The guide was previously validated with a smaller sample of volunteers sharing the same characteristics as the study population to refine the language and ensure clear understanding of the questions.

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Table 1. Participant’s interview guide.

https://doi.org/10.1371/journal.pone.0333408.t001

The IDIs and FGDs were conducted face to face by the qualitative researchers [APCS (Alícia Patrine Cacau Dos Santos, PhD), EARTS (Evellyn Antonieta Rondon Tomé Silva, master’s degree student), and HSSG (Hiran Sátiro Souza da Gama, master’s degree student)],all healthcare professionals and field researchers with training and experience in qualitative data collection. The IDIs and FGDs were scheduled according to participant availability, with an average duration of 40 minutes for IDIs and 60 minutes for FGDs. Both were conducted in quiet, comfortable locations such as participants’ homes, schools, or church community buildings, where only researchers, observers, and participants were present. Data generated through the IDIs and FGDs were audio-recorded, documented in field notebook entries, and supplemented by participant observations conducted by the team, enabling data triangulation during analysis.

Results

The study included a total of 32 participants (Table 2), comprising 15 in-depth individual interviews and 3 focus group discussion participants across three distinct groups: a women’s group (n = 5), a men’s group (n = 5), and an adolescent group (n = 7). Participants. During early data collection, researchers observed that gender and age dynamics could influence participant responses. To account for this, focus groups were conducted separately.

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Table 2. Participant’s characteristics.

https://doi.org/10.1371/journal.pone.0333408.t002

The data analysis identified two main themes. The first, Impacts of Amazonian Seasonality on Healthcare Access for Riverine Communities, explores the challenges in seeking medical assistance during both dry and flood seasons. The second, Arrivals and Departures Along the Banks of the Solimões River, addresses women’s health at various life stages—pregnancy, childbirth, and postpartum and includes accounts of stillbirths during these journeys.

Discussion

This study highlights how the unique climatic conditions of the Amazon significantly influence the health and well-being of riverine populations. Seasonal extremes, including geographic isolation, food and water insecurity, increased health risks, and healthcare access barriers, pose compounding challenges for these communities. In the Peruvian Amazon for example, flood seasons replicate these patterns, particularly through increased exposure to venomous animals, heightened risk of child drownings, as reported by our participants, and severe impacts on subsistence farming in Peru [26]. During extreme droughts, regional evidence confirms systematic links to food insecurity, water source contamination, and potable water shortages, creating critical sanitation crises [27]. These findings reveal the critical interplay between environmental factors and healthcare access, showing how climate variability exacerbates vulnerabilities. For instance, the contamination of water sources during droughts and floods leads to increased gastrointestinal diseases, while geographic isolation during extreme events severely limits access to emergency care. Addressing these compounded vulnerabilities underscores the essential role of environmental health in improving resilience and mitigating disparities in climate-impacted populations.

While our qualitative data focus on Tabatinga, these experiences mirror those of vulnerable riverine communities worldwide. Indeed, the World Health Organization (WHO) estimates that 3.6 billion people live in regions highly vulnerable to extreme weather events and climate variability. In these areas, it is projected that between 2030 and 2050, climate-related impacts will lead to approximately 250,000 additional deaths annually, primarily due to malnutrition, malaria, diarrhea, and heat stress [28]. Regions with inadequate health service infrastructure are expected to be disproportionately affected [29].

The study revealed that seeking care largely dependent on riverine transportation has consistently faced challenges from seasonal fluctuations, financial constraints, and long distances [13]. These issues have been worsened by the climate crisis, making essential needs (potable water, food security, and basic medical services) increasingly out of reach [29,30]. These implications extend to vulnerable populations worldwide. Communities dependent on natural resources and river systems face similar challenges: waterborne diseases, disrupted livelihoods, and geographic isolation due to climate change. Addressing these issues requires integrated solutions that balance environmental sustainability and public health needs.

As a result, millions may face food insecurity due to these communities’ heightened economic vulnerability. Many rely on fishing and stable temperatures for subsistence farming. The lack of nutritious, safe food undermines health, leading to more infectious and chronic diseases, malnutrition, and weakened immunity, particularly among children and the elderly. This food insecurity also aggravates the prevalence and severity of neglected diseases in the region, perpetuating a cycle of vulnerability and deteriorating health conditions.

Droughts and floods also hinder potable water access, leading to more gastrointestinal diseases among children, potentially fatal and contributing to high or rising infant mortality rates [31,32]. Evidence suggests that global changes may accelerate infectious disease emergence by disrupting ecosystem balance [33].

Addressing future health challenges requires healthcare systems to adapt to barriers posed by extreme climatic events. Priority actions include deploying mobile healthcare units, enhancing transportation networks, and expanding telemedicine platforms tailored to remote riverine communities. These must address the rising burden of injuries, deaths, and infectious diseases linked to extreme weather and unsafe water and food. Tackling food and water insecurity is equally critical to reducing long-term health impacts on vulnerable populations [34].

According to the 2022 Climate Inequality Report [35], climate change risks and impacts are unevenly distributed, intensifying social inequalities, particularly in access to healthcare. This dynamic contributes to worsening Brazil’s already low primary care coverage rates [17,19,35]. Addressing situations like those described here will likely become more common, as populations and healthcare systems struggle with accelerating changes.

Involuntary relocation, as observed with pregnant women in this study, is a recurring reality, especially in the pursuit of better access to healthcare and education. Projections suggest that displacement will increase in coming decades; however, this phenomenon is often tied to precarious living conditions, with higher risks of violence and insecurity [36,37]. For riverine communities, displacement also causes profound disruptions and may even erase their way of life, since identity is intrinsically tied to their connection with nature [38].

To prevent thousands of deaths, WHO [28] outlines three key objectives: reduce carbon emissions while improving health outcomes; build stronger, climate-resilient, environmentally sustainable healthcare systems; and safeguard health from climate change impacts. Consequently, healthcare systems must prioritize enhancing access, particularly addressing the unique needs of traditional riverine communities.

As of 2020, only 13 river ambulances served all urgent and emergency cases nationwide—far fewer than needed for the riverine population [39]. Additionally, river transport is increasingly impractical due to prolonged droughts, underscoring healthcare systems’ urgent need to adapt. Climate change is escalating into the most significant threat to human health in the 21st century [40].

As a theoretical framework for addressing the health challenges we indicate the use of Ostrom’s approach, especially for governmental organizations [41]. The framework provides a robust foundation for mapping interactions among socio-ecological variables. It enables the identification of vulnerability factors as well as opportunities for local public policies that integrate traditional knowledge and institutional innovation. By doing so, this approach avoids generic solutions, instead promoting adaptive interventions tailored to the actual needs of riverine populations in the face of climate change.

Besides adapting the healthcare system indicated by WHO, it is essential to consider the concept of ancestral futures, a perspective advocated by the Indigenous movement in Brazil and championed by Ailton Krenak [42], a prominent Indigenous thinker. This concept emphasizes the value of Indigenous knowledge in shaping strategies to address this critical moment. A paradigmatic example of this synergy can be observed in sustainable environmental management, where Indigenous knowledge plays a decisive role in ecosystem preservation. It is crucial to understand that the health of traditional communities is intrinsically tied to socio-environmental justice, revealing the interdependence between human well-being and ecological balance. This holistic vision requires integrating diverse knowledge systems. As demonstrated by [43] on moringa seed filtration of contaminated water, a practice elders identified as historically effective, such techniques could be incorporated into mobile clinic protocols. This would both immediately reduce gastrointestinal illnesses and validate traditional knowledge systems. However, it is important to remember that the water is filtered because the river is sick, but the cure comes from the standing forest. Thus, while moringa filtration is a crucial emergency measure, the structural solution requires climate justice: protecting springs, combating illegal mining, restoring degraded areas, and addressing the root causes of water scarcity through land rights and fire prevention policies. Within this epistemic landscape, a recent study conducted by indigenous researchers highlighted similarities and differences between modern scientific knowledge and Indigenous Amazonian knowledge. It proposes alternatives for dialogue and integration, combining modern conservation science strategies with Indigenous knowledge, as a pathway to the regional sustainability [44].

Due to the specific cultural and geographical characteristics of the riverine community studied and considering that data were collected inly from June to December (a single weather cycle) the results may not reflect the experiences and perceptions of all Brazilian Amazon riverine communities. Additionally, nuances of local expressions may have been lost in translation from Portuguese to English.

Conclusions

This study highlights the profound health impacts of climatic events on traditional riverine communities shaped by Amazonian seasonality. The increasing frequency and severity of droughts and floods disrupts daily life, exacerbating healthcare access, food security, and transportation challenges. Urgent measures are needed to implement adaptable healthcare systems and sustainable infrastructure, including telemedicine platforms, mobile clinics, and resilient transportation networks. Investments in communication infrastructure and air emergency transportation are critical as riverine navigation becomes increasingly unreliable. Because participants described waiting days for boats or relying on relatives for childbirth, these interventions directly address their most pressing barriers. Embracing the concept of ancestral futures emphasizes humanity’s interconnectedness with the environment and provides a framework for sustainable solutions. Sustainable environmental and water resource management in the Amazon for example, when conducted with ecological balance and respect for biome limits, serves as a critical strategy for preventing the emergence and spread of socially determined diseases. By mitigating environmental degradation and natural resource depletion, key drivers of health vulnerabilities, this approach supports the maintenance of functional ecosystems capable of regulating disease vectors; the preservation of water sources meeting qualitative standards for human consumption; and the sustainability of traditional livelihoods intrinsically linked to collective health.

These strategies can enhance resilience, improve the quality of life for riverine populations, and preserve their cultural and environmental heritage while serving as a model for addressing similar challenges in other climate-vulnerable regions. Although our findings come from one tri‐border community, future studies should examine other Amazonian regions to refine these recommendations.

Supporting information

Acknowledgments

We extend our gratitude to all riverine participants, whose contributions were essential to the development of this study.