Impact of the 1742–1743 Plague Epidemic on Global Excess Deaths and Social Dynamics in the City of Santa Fe and Along the Royal Road Between Buenos Aires and Lima

Abstract

The 1742–1743 plague epidemic significantly impacted Santa Fe, a key city along the Royal Road (Camino Real), a vital colonial trade route connecting Buenos Aires and Lima. This study examines the epidemic’s demographic and socio-economic consequences in Santa Fe, focusing on excess mortality and its disproportionate impact on marginalized groups, such as Indigenous and African-descended populations. Utilizing parish records, census data, and archival sources, the research quantifies mortality rates during the epidemic and highlights the role of Santa Fe’s strategic position in facilitating the rapid spread of the disease. The findings underscore the intersection of systemic vulnerabilities and territorial dynamics shaped by Bourbon reforms, which exacerbated the epidemic’s effects. Furthermore, this study explores the resilience of local communities, emphasizing how cultural and religious practices contributed to recovery. By situating Santa Fe’s experience within the broader context of the Royal Road, this research provides a nuanced understanding of the complex interplay between epidemics, social structures, and demographic change in colonial Latin America, offering valuable insights for contemporary public health strategies.

1. Introduction

The 1742–1743 plague epidemic marked a critical moment in the demographic and social history of colonial South America, particularly along the Royal Road (Camino Real), the principal trade route connecting Buenos Aires and Lima (Huamán 2019). While the transformative role of epidemics, especially plague, in shaping societies has been extensively studied in Europe, its impact on 18th-century South America remains underexplored (Jori 2013). This study delves into the profound demographic and socio-economic impacts experienced by key urban centers such as Córdoba and Santa Fe, situated along this vital trade route (Kilgore et al. 2024).

Historical records indicate that the epidemic severely disrupted the social and economic infrastructures of cities such as Córdoba and Buenos Aires, extending its devastation to Santa Fe (Choque Mariño and Muñoz Ovalle 2016; Goytia 2005). Unlike in Europe, where disease propagation was often accelerated by global trade and environmental factors, the spread of the plague in South America was primarily facilitated by the movement of goods and people along the Camino Real, heightening the susceptibility of particularly marginalized groups including enslaved and Indigenous populations (Villafañe 2025). Historical accounts from Jesuit missions further illustrate the epidemic’s disruptive impact, as survivors fled to the mountains and abandoned their settlements in search of refuge, leading to the suspension of religious and educational activities, while communities were overwhelmed by grief and loss (Crespo and Nájera 2020).

In this context, the term ‘excess mortality’ refers to the number of deaths during a specific period that exceeds the amount that would normally be expected based on previous years. This measure is fundamental for assessing the demographic consequences of extraordinary events, such as epidemics, on population dynamics. This study employs excess mortality as a quantitative indicator, integrating the methodological framework proposed by Arrizabalaga (1999), which emphasizes the socio-cultural construction of death and the interpretative challenges inherent in historical mortality records (Arrizabalaga 1999). Specifically, Arrizabalaga highlights the complexities of retrospective diagnosis, the influence of medicalization processes on death certification, and the epistemological limitations of assigning causes of death in pre-industrial societies.

Given the absence of standardized medical nosology in the 18th century, this study aligns with Arrizabalaga’s critique of anachronistic interpretations of historical mortality data. Instead of imposing modern diagnostic categories onto past epidemics, the approach adopted here acknowledges the fluidity of disease definitions and relies on comparative mortality trends rather than rigid disease classifications. Furthermore, the study considers the interplay between institutional record-keeping practices, religious frameworks, and vernacular interpretations of illness, all of which shaped how deaths were recorded and understood in colonial South America. These methodological considerations ensure a historically grounded analysis of the epidemic’s demographic impact, particularly on marginalized communities (Simonsen et al. 2006).

While targeted studies in Córdoba and Buenos Aires have shed light on the urban ramifications of the plague, the broader regional effects remain underexamined (Celton 1998). Documentation from Jesuit missions, like those in San Miguel, present-day Bolivia, reveal that an outbreak in late 1741 suggests that the trade and missionary pathways along the Camino Real were crucial in the dissemination of the plague (Matienzo et al. 2011; Santamaría 1986; Villafañe 2023).

Further accounts from Frías and Montserrat (2017) (Frías and Montserrat 2017), describe the epidemic’s severe nature and the local communities’ reliance on traditional and spiritual healing practices, which underscores a limited understanding of the disease’s transmission mechanisms, Figure 1.

Concurrent to these events, the Bourbon reforms aimed at restructuring colonial governance, which significantly altered the administrative, economic, and social frameworks within the Spanish colonies. These changes, intended to centralize authority and enhance administrative efficiency, inadvertently impacted the regions’ ability to manage and recover from health crises, altering local governance and health responses, thereby setting a crucial context for the epidemic’s progression (Sánchez Santiró 2016).

This research quantifies excess mortality in Santa Fe during the 1742–1743 epidemic and examines its broader social implications. By analyzing parish death records, censuses, and archival sources, it explores how the epidemic reshaped Santa Fe’s demographic structure and disrupted its socio-economic fabric. Additionally, it investigates the resilience of local communities, contributing to a deeper understanding of the interplay between epidemics and societal transformation in colonial Latin America.

2. Materials and Methods

This study evaluates the demographic impact of the 1742–1743 plague epidemic in Santa Fe, employing excess mortality as a key metric. This method addresses the diagnostic limitations of 18th-century medical practices by capturing both direct and indirect mortality effects associated with the epidemic.

2.1. Estimation of Excess Mortality

Excess mortality was calculated using parish records from Santa Fe, selected for their completeness and consistency. Mortality trends were analyzed by comparing death counts during the epidemic to those recorded in pre- and post-epidemic periods. This approach facilitates quantifying mortality attributable to the epidemic in the region.

2.2. Review of Primary Sources

The primary dataset consisted of parish death records from Santa Fe, categorized into three temporal phases (Villafañe 2022):

• Pre-epidemic period: January 1740–December 1741.
• Epidemic period: January 1742–December 1743.
• Post-epidemic period: January 1744–December 1745.

To address missing entries (e.g., age or marital status), complementary sources such as baptismal and marriage registers were consulted. Additionally, census data from 1744 provided critical insights into population structure during the post-epidemic recovery phase.

2.3. Comparative and Cross-Referencing Analysis

Mortality data from Santa Fe parish records were cross-referenced with complementary sources, including administrative and census records, to contextualize mortality trends within broader social and economic conditions. This multi-source approach strengthens the interpretative framework and enhances understanding of the epidemic’s demographic and socio-economic impacts.

2.4. Considerations on the Record-Keeping System

The study acknowledges challenges in historical record-keeping systems, including potential underreporting or inconsistencies. Methodological adjustments were made to harmonize absolute death counts and relative mortality estimates, ensuring the validity of excess mortality analyses for Santa Fe.

3. Results

3.1. Epidemiological Characteristics of the Plague in Santa Fe

3.1.1. Comparative Mortality

The mortality data for Santa Fe during the 1742–1743 plague epidemic reveals a significant increase in deaths during the epidemic phase compared to pre- and post-epidemic periods. As shown in

Table 1. Comparative mortality rates during the pre-epidemic, epidemic, and post-epidemic phases in Santa Fe (1740–1745).

Month	Pre Peste 1740/1	Plague 1742/3	Post Peste 1744/5
January	7 (5.7%)	25 (14.1%)	8 (6.1%)
February	9 (7.4%)	10 (5.6%)	7 (5.3%)
March	7 (5.7%)	14 (7.9%)	5 (3.8%)
April	19 (15.6%)	13 (7.3%)	14 (10.6%)
May	6 (4.9%)	4 (2.3%)	13 (9.8%)
June	10 (8.2%)	13 (7.3%)	15 (11.4%)
July	9 (7.4%)	16 (9.0%)	12 (9.1%)
August	12 (9.8%)	8 (4.5%)	15 (11.4%)
September	4 (3.3%)	16 (9.0%)	11 (8.3%)
October	7 (5.7%)	12 (6.8%)	10 (7.6%)
November	12 (9.8%)	15 (8.5%)	9 (6.8%)
December	20 (16.4%)	28 (15.8%)	13 (9.8%)
Total	122 (100%)	177 (100%)	132 (100%)

, total deaths during the epidemic phase (177) were 45% higher than in the pre-epidemic period (122) and remained elevated during the post-epidemic recovery period (132). The peak in mortality occurred in December 1743, with 28 deaths (15.8%), highlighting the epidemic’s acute impact. This pattern underscores the severe demographic disruption caused by the epidemic.

To better capture seasonal trends, mortality data were consolidated by season, Figure 2. This approach provides a clearer depiction of the temporal distribution of deaths and helps to contextualize the epidemic’s impact relative to natural mortality fluctuations. The seasonal analysis highlights a pronounced peak in mortality during the summer months, corresponding to the epidemic period. A sharp decline is observed in autumn, followed by a gradual increase in winter and spring, reflecting the persistence of elevated mortality even after the acute phase of the epidemic had subsided.

3.1.2. Mortality by Sex, Age, and Marital Status

Demographic analysis of mortality in Santa Fe reveals variations by sex, age, and marital status (

Table 2. Mortality Distribution by Sex, Age, and Marital Status.

	Pre-Plague 1740/1	Plague 1742/3	Post-Plague 1744/5
Gender, female %	43.4%	40.7%	35.6%
Age, adult (≥18) %	57.4%	69.6%	62.1%
Marital status, single %	43.4%	28.8%	33.3%

). Female mortality was slightly lower during the epidemic phase (40.7%) compared to the pre-epidemic period (43.4%), suggesting potential differences in exposure or vulnerability. Mortality among adults (≥18 years) increased significantly, rising to 69.5% during the epidemic phase, compared to 57.4% pre-epidemic. This indicates that working-age individuals were particularly affected. The proportion of single individuals among the deceased dropped to 28.8% during the epidemic, reflecting possible shifts in exposure risks or social dynamics during the outbreak.

3.1.3. Ethnic Composition

Table 3. Ethnic Distribution of Mortality in Santa Fe.

Ethnicity	Pre Peste 1740/1	Plague 1742/3	Post Peste 1744/5
Spanish	18 (14.8%)	24 (13.6%)	23 (17.4%)
Creole	52 (42.6%)	93 (52.5%)	61 (46.2%)
Indigenous/African	37 (30.3%)	48 (27.1%)	25 (18.9%)
Pardo	7 (5.7%)	4 (2.3%)	5 (3.8%)
Mulatto	3 (2.5%)	3 (1.7%)	1 (0.8%)
Mestizo	10 (8.2%)	8 (4.5%)	4 (3.0%)
Total	122 (100%)	177 (100%)	132 (100%)

Spanish: Purely European descent; Creole: European descent born in the Americas; Indigenous/African: Combined due to historical record practices not distinctly maintaining separate records for each group; Pardo: Mixed European, African, and sometimes Indigenous descent; Mulatto: Mixed European and African descent; Mestizo: Mixed Indigenous and European descent.

illustrates the ethnic disparities in mortality during the plague epidemic in Santa Fe. Populations of Indigenous and African descent were significantly affected, collectively accounting for over 55% of the deaths during the epidemic phase, underscoring the heightened vulnerability of these groups. The data shows that the Indigenous/African group accounted for 27.1% of the deaths during the plague, while maintaining a considerable portion of mortality figures in both the pre- and post-epidemic periods.

Contrary to earlier misreported increases, the “Pardo” group experienced a decrease in mortality during the epidemic, dropping from 5.7% pre-epidemic to 2.3% during the epidemic. This change is significant as it may suggest variations in exposure or survival strategies among this demographic group during the epidemic, challenging assumptions about uniform vulnerability across ethnic lines.

The mortality data for other ethnic groups such as the Creoles and Spanish illustrates shifting dynamics during and after the epidemic. Creoles, for instance, experienced the highest mortality at 52.5% during the epidemic, reflecting their substantial demographic presence and possibly higher interaction within urban centers where the plague’s transmission dynamics were more intense.

4. Discussion

The results confirm that excess mortality is an effective metric for assessing the scope of the epidemic, which disproportionately affected marginalized groups such as Indigenous and African-descended populations. This analysis elucidates the structural vulnerabilities inherent in interconnected trade networks and systemic inequities, which exacerbated the impact of the epidemic. Moreover, the research highlights the resilience mechanisms activated during the recovery phase, providing critical insights into societal adaptations post-crisis.

The epidemic laid bare the vulnerabilities of colonial trade networks while also illuminating the adaptive strategies that mitigated these effects. For instance, the Santa Fe city council’s sanctioning of religious practices, including novenas to Saints Jerónimo and Roque, addressed both the epidemic and simultaneous drought conditions. These actions demonstrate the integration of spiritual and administrative responses, serving as pivotal components of the public health strategy during this period (Villafañe 2024). This synergy between cultural practices and crisis management underscores the vital role of religious frameworks in enhancing social cohesion and resilience.

4.1. Excess Mortality and Vulnerable Populations in Santa Fe

During the epidemic, mortality in Santa Fe increased by 45% compared to the pre-epidemic period, disproportionately affecting marginalized groups, particularly Indigenous and African-descended populations, which accounted for over 60% of recorded deaths. The Pardo population, consisting of individuals of mixed ancestry, exhibited the most pronounced rise in mortality, increasing from 7.4% in the pre-epidemic phase to 23.4% during the outbreak. These demographic trends underscore the interaction between social stratification and epidemiological vulnerability, a pattern similarly documented in other colonial contexts (Celton 1998; Choque Mariño and Muñoz Ovalle 2016; Goytia 2005).

The findings reveal how epidemics disproportionately affected marginalized populations, such as the enslaved and Indigenous, due to factors such as labor exploitation, precarious living conditions, and reliance on traditional healers or religious institutions for care, as formal medical assistance was scarce and largely inaccessible in colonial society (Arrizabalaga 1999). These vulnerabilities were especially pronounced within Jesuit missions, where Indigenous communities faced increased risks due to enforced sedentarization and the disruption of traditional social structures (Santamaría 1986; Santamaría and Peire 1993).

The Cartas Anuas illustrate the intricate relationship between epidemic outbreaks and mobility along the Camino Real. Historical records document extensive population displacement, as Indigenous groups abandoned missions and settlements in an effort to evade contagion, mirroring the demographic upheavals observed in Santa Fe. This pattern of migration not only facilitated the dissemination of the disease but also disrupted regional economies and colonial governance structures (Vega 2023). The prevalent Jesuit interpretation of the epidemic as divine retribution significantly influenced communal responses, reinforcing religious explanations for the crisis and prompting large-scale spiritual interventions. These accounts serve to complement the quantitative analysis of mortality by offering qualitative perspectives on the lived experiences of affected populations, thereby enriching our comprehension of the socio-cultural ramifications of the epidemic (Crespo and Nájera 2020).

4.2. Demographic Impact and Socioeconomic Disruptions

The demographic impact in Santa Fe was particularly pronounced among working-age adults (≥18 years), who represented 69.5% of epidemic-related deaths compared to 57.4% in the pre-epidemic period. This significant shift highlights the epidemic’s disruptive effects on labor forces, which further destabilized local economies and social structures. Additionally, the proportion of single individuals among the deceased decreased from 43.4% pre-epidemic to 28.8% during the outbreak, suggesting changes in exposure risks, likely influenced by family roles or living arrangements.

The epidemic’s ethnic disparities further illustrate its socio-economic disruptions. Indigenous and African-descended populations, already vulnerable due to entrenched inequalities, suffered disproportionately. These patterns are consistent with studies that emphasize the role of social determinants in shaping health outcomes during historical epidemics (AGI 1736; Frías and Montserrat 2017). Santa Fe’s experience highlights how epidemics not only cause direct demographic losses but also exacerbate broader socio-economic tensions and inequalities.

4.3. Santa Fe’s Experience Within the Royal Road Context

Santa Fe’s position along the Royal Road represented both an advantage and a vulnerability. As a key logistical hub, the city’s connectivity facilitated trade and migration, contributing to its economic importance within the colonial network. However, these same networks also accelerated the spread of the epidemic. Historical records emphasize that regional movements of people and goods were central to the disease’s transmission (Celton 1998; Goytia 2005).

The epidemic’s progression underscores the multifaceted interactions between environmental, social, and economic factors that defined its dynamics (Ruiz 2001). Santa Fe’s experience aligns with broader patterns observed in other epidemic contexts, such as those of Jesuit missions, where cultural frameworks and socio-economic structures shaped both vulnerability to and resilience against epidemics (Santamaría 1986). These insights contribute to a deeper understanding of the complex challenges faced by communities along the Royal Road and the systemic factors that amplified the impacts of historical health crises.

4.4. Community Resilience and Recovery

Despite the severe impact of the epidemic, Santa Fe exhibited notable resilience in the post-crisis period. Religious and communal practices, such as novenas and public prayers, played a crucial role in restoring social cohesion and fostering a collective sense of hope (Villafañe 2024). Archival records from 1744 indicate signs of demographic stabilization, suggesting that localized responses mitigated the long-term socio-economic consequences of the outbreak (Frías and Montserrat 2017).

This pattern aligns with broader historical trends, where cultural frameworks and communal strategies shaped recovery processes following epidemic events (Rosso 2011; Santamaría 1986). The ability of Santa Fe’s population to reorganize underscores the significance of community-driven mechanisms in the reconstruction process. These responses illustrate how religious practices, social networks, and local adaptive strategies contributed to resilience in the aftermath of the crisis, reinforcing the role of cultural and institutional continuity in mitigating the disruptive effects of epidemics.

4.5. Broader Implications for Historiography and Public Health

This study addresses a significant gap in the historiography of South American epidemics by focusing on Santa Fe, a city often overshadowed by larger urban centers like Buenos Aires or Jesuit missions. The findings highlight the importance of localized studies to capture the diverse impacts of historical epidemics and their nuanced socio-economic implications.

The parallels between the 1742–1743 epidemic and modern health crises, such as COVID-19, underscore the persistence of systemic vulnerabilities. Both crises demonstrate how marginalized populations disproportionately bear the brunt of health emergencies, emphasizing the importance of equity-focused public health strategies (De La Puente Brunke 2002; Pedersini et al. 2020; Rearte et al. 2021). Furthermore, Santa Fe’s recovery illustrates the enduring value of community resilience in overcoming crises, offering lessons for contemporary crisis management and public health planning.

4.6. Limitations of the Study

This study is subject to several limitations inherent to its historical and methodological framework. Reliance on parish death records introduces potential biases due to incomplete or inconsistent documentation. Cause-of-death records in the 18th century often reflected cultural or religious interpretations rather than medical diagnoses, complicating the attribution of mortality to the plague. Additionally, underreporting and the absence of standardized record-keeping pose further challenges to precise mortality estimations.

The use of excess mortality as a key metric assumes stable demographic trends during the pre- and post-epidemic periods. However, factors such as migration, natural disasters, or other concurrent diseases may have influenced mortality rates, potentially leading to over- or underestimation of the epidemic’s impact.

Finally, while this study focuses on Santa Fe, its findings may not fully capture regional variations in epidemic dynamics. Future research could benefit from integrating interdisciplinary perspectives to explore broader patterns of epidemic spread and impact across colonial Latin America.

5. Conclusions

The 1742–1743 plague epidemic had profound demographic and socio-economic impacts on Santa Fe, clearly exposing the vulnerabilities of marginalized populations and the fragility of interconnected colonial systems during public health crises. Excess mortality analysis revealed that Indigenous and African-descended groups bore a disproportionate burden, highlighting how entrenched systemic inequalities exacerbated the epidemic’s effects, thereby destabilizing social and economic structures.

Santa Fe’s strategic location along the Royal Road exemplified the dual nature of connectivity, simultaneously facilitating economic activity and accelerating disease transmission. The concurrent Bourbon reforms intensified regional disparities and vulnerability, further compounding the crisis. Despite these significant challenges, the community in Santa Fe demonstrated notable resilience, with cultural and religious practices playing a crucial role in re-establishing social cohesion and promoting recovery.

This study fills a significant historiographical gap by emphasizing the regional experiences of Santa Fe within the broader context of the Royal Road network, providing valuable insights into the complex relationship between epidemics, societal transformation, and resilience. The parallels drawn with contemporary epidemics, such as COVID-19, underscore enduring systemic vulnerabilities and the critical importance of equity-focused public health interventions and culturally informed recovery frameworks. Ultimately, bridging historical perspectives with contemporary experiences underscores the necessity of addressing structural inequalities and fostering resilience to mitigate future global health crises.