CLIMATE CHANGE AND PUBLIC HEALTH RISKS: FLOODING AND DISEASE OUTBREAKS MANAGED AT NNAMDI AZIKIWE UNIVERSITY TEACHING HOSPITAL

CHAPTER ONE

INTRODUCTION

1.1 Background to the Study

Climate change represents one of the most significant and complex threats to global public health in the twenty-first century, with cascading effects on the epidemiology of infectious diseases, the burden of malnutrition, the displacement of populations, and the functionality of health systems. In Nigeria, climate-related hazards particularly flooding have emerged as proximate drivers of disease outbreaks, food insecurity, and health system strain. The catastrophic October 2022 floods in Nigeria killed over 600 people, displaced more than 1 million individuals, and triggered a major upsurge in cholera and other preventable diseases (International Rescue Committee, 2023). Prior to October 2022, the Nigeria Centre for Disease Control (NCDC) had already confirmed over 2,000 cholera cases and 233 deaths across 31 states between January and September 2022 (NCDC, 2022).

The intersection of flooding and infectious disease transmission is well-documented in the public health literature. Flooding creates standing water that constitutes ideal breeding habitats for malaria vectors, and contaminates drinking water sources with faecal matter, potentiating cholera and typhoid transmission (Aborode et al., 2025). A cholera outbreak trend analysis published in Frontiers in Public Health (2024) confirmed that Nigeria's cholera burden is driven by a confluence of meteorological, socioeconomic, and sanitation factors, with climate change and flooding among the most significant environmental amplifiers (Frontiers, 2024). More recently, Nigeria experienced above-average rainfall in 2024, with prolonged and intense rainy periods leading to widespread flooding across multiple states including Adamawa, Borno, and Yobe, overwhelming sanitation infrastructure and facilitating further pathogen spread (Akingbola et al., 2025). In 2024, the WHO African region reported 19,452 cholera cases and 711 deaths across all 36 states and the FCT as of December 22, representing a continued and severe public health burden (IWA Publishing, 2025).

The relationship between flooding and disease outbreaks is well-established in the public health literature. Flooding disrupts water and sanitation infrastructure, destroys farmland and food reserves, and creates conditions of severe food insecurity that further compromise community health and resilience (Aborode et al., 2025). A case study of the 2022 flood outbreak in Nigeria documented these dynamics, finding that vector-borne and waterborne diseases spiked sharply in flood-affected communities, placing severe demands on health facility resources (Ijioma & Oguike, 2024). Nnamdi Azikiwe University Teaching Hospital (NAUTH), Nnewi, Anambra State, serves as a critical tertiary referral centre in southeast Nigeria, managing climate-sensitive disease presentations that include malaria, typhoid, cholera, and diarrhoeal diseases in the context of increasingly erratic rainfall and flooding.

In Borno State, a 2025 public health analysis documented that September 2024 flooding driven by heavy rainfall and dam infrastructure damage affected over 200,000 people, killed 30, and displaced 50,000, while simultaneously triggering surges in cholera and diphtheria presentations at already overstretched health facilities (Aborode et al., 2025). These climate-health dynamics are not geographically confined to the northeast; Anambra State and the South-East zone of Nigeria are also characterised by intense seasonal rainfall, gully erosion, and periodic flooding that represent ongoing threats to community and hospital-level public health management. A five-decade review of cholera outbreaks in Nigeria concluded that the country's cholera burden is perpetuated by inadequate water, sanitation, and hygiene (WASH) infrastructure, weak health systems, poor surveillance, and the compounding effects of climate change (PMC, 2025).

1.2 Statement of the Problem

Despite growing awareness of climate change as a public health risk, the specific burden of climate-related disease presentations particularly flooding-associated disease outbreaks at tertiary hospitals such as Nnamdi Azikiwe University Teaching Hospital has not been systematically quantified or analysed. NAUTH manages a significant volume of climate-sensitive disease presentations, yet epidemiological data linking flood events to disease outbreak patterns at the hospital level remain fragmented and unpublished. This gap limits the hospital's ability to implement proactive climate-sensitive health system preparedness measures.

Analysis of Nigeria's cholera patterns reveals that while national surveillance data document aggregate outbreak data, facility-level contributions to managing flood-associated disease surges and the resource implications remain poorly understood (IWA Publishing, 2025; PMC, 2025). A study examining the microbial disease burden associated with climate change in Nigeria found that the compounding effects of flooding, poor sanitation, and inadequate water treatment create an environment in which cholera and other climate-sensitive diseases flourish, yet health facility responses remain reactive rather than proactive (SSR Publisher, 2025). Globally, research has demonstrated that health facilities in flood-prone areas experience surges in patient volumes, supply shortages, and infrastructure damage during and after flood events (Ijioma & Oguike, 2024), yet the Nigerian tertiary hospital experience has been inadequately documented, limiting evidence-based health system climate adaptation planning.

1.3 Objectives of the Study

The main objective is to examine the impact of climate change, specifically flooding and associated disease outbreaks, on public health management at Nnamdi Azikiwe University Teaching Hospital, Nnewi.

The specific objectives are to:

1. document the pattern of climate-sensitive disease presentations managed at NAUTH over the study period, with focus on flooding-related outbreaks;
2. establish the temporal association between flood events in Anambra State and surges in disease outbreak presentations at NAUTH;
3. assess the health system preparedness and response capacity of NAUTH in managing climate-related disease outbreaks;
4. identify the sociodemographic and environmental risk factors associated with flooding-related disease presentations at NAUTH

1.4 Research Questions

1. What is the pattern of climate-sensitive disease presentations managed at NAUTH?
2. Is there a significant temporal association between flood events in Anambra State and disease outbreak presentations at NAUTH?
3. How prepared and responsive is NAUTH to climate-related disease outbreaks?
4. What sociodemographic and environmental factors are associated with flooding-related disease presentations at NAUTH?

1.5 Research Hypotheses

H01: There is no significant association between annual flood intensity in Anambra State and the volume of waterborne disease presentations at NAUTH.

H02: Climate-related disease outbreak presentations at NAUTH do not significantly exceed non-outbreak baseline levels during identified flood periods.

H03: NAUTH's current health system preparedness does not significantly differ from minimum WHO climate-resilient health facility standards.

1.6 Significance of the Study

This study provides the first systematic facility-based analysis of climate-attributable disease burden at NAUTH, contributing critical evidence to inform the hospital's climate resilience planning. The findings are relevant to the Federal Ministry of Health, Anambra State Ministry of Health, the Nigeria Centre for Disease Control and Prevention, and climate-health researchers. The study also contributes to the growing global literature on climate change and health facility burden in low- and middle-income countries, addressing a significant evidence gap in the West African context. The findings will be particularly timely given the documented intensification of flood events and climate-sensitive disease burden in Nigeria through 2024 (Akingbola et al., 2025; IWA Publishing, 2025), and will support evidence-based advocacy for improved WASH infrastructure and climate-resilient health facility investments.

1.7 Scope and Limitations of the Study

The study is conducted at Nnamdi Azikiwe University Teaching Hospital, Nnewi, Anambra State, covering a five-year retrospective review of climate-sensitive disease presentations alongside prospective data collection. Limitations include: incomplete hospital records for earlier years in the study period; difficulty in attributing individual disease presentations definitively to flood events rather than endemic transmission; the absence of a comparison hospital to assess counterfactual trends; and the evolving nature of climate patterns, which may limit the temporal generalisability of findings.

1.8 Definition of Terms

Climate Change: A long-term shift in global and regional climate patterns, manifesting as changes in temperature, precipitation, sea levels, and the frequency and intensity of extreme weather events such as floods, droughts, and storms.

Flooding: The overflow of water onto normally dry land, typically caused by heavy precipitation, river overflow, storm surge, or failure of water management infrastructure, resulting in significant disruption to communities and health systems.

Disease Outbreak: The occurrence of disease cases in a given area and period that exceeds the expected normal incidence, requiring a coordinated public health response.

Climate-Sensitive Disease: A disease whose incidence, prevalence, distribution, or severity is significantly influenced by climatic variables such as temperature, rainfall, humidity, and flooding. Examples include malaria, cholera, typhoid, and dengue fever.

Waterborne Disease: A disease caused by pathogenic micro-organisms transmitted through contaminated water, including cholera, typhoid fever, dysentery, and hepatitis A.

Vector-Borne Disease: A disease transmitted to humans through the bite of infected arthropod vectors, including mosquitoes (malaria, dengue), ticks, and flies. Vector populations are strongly influenced by climatic conditions.

Health System Climate Resilience: The capacity of a health system to anticipate, respond to, cope with, recover from, and adapt to climate-related shocks and stresses while maintaining its core functions.

WASH: Water, Sanitation, and Hygiene the integrated set of services, facilities, and practices essential to preventing waterborne disease transmission and maintaining public health, particularly in flood-prone and resource-limited settings.

Climate Adaptation: Adjustments in natural or human systems in response to actual or expected climatic stimuli or their effects, aimed at moderating harm or exploiting beneficial opportunities.

References

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Frontiers in Public Health. (2024). Cholera outbreak trends in Nigeria: Policy recommendations and innovative approaches to prevention and treatment. Frontiers in Public Health, 12. https://doi.org/10.3389/fpubh.2024.1464361

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