Sanitation and clean water: analysis of current access to clean water and sanitation facilities
Cholera outbreaks in Nigeria are linked to inadequate access to safe water and poor sanitation. Despite abundant water resources, regional disparities in water availability and management contribute to recurrent outbreaks [25]. The Nigerian government, with support from United Nations Children’s Fund (UNICEF) and the Global Task Force on Cholera Control (GTFCC), prioritizes WASHas a key prevention strategy [16]. However, these efforts face persistent challenges.
Access to clean water
Nigeria has substantial water resources, including an estimated 215 billion cubic meters of surface water and 87 billion cubic meters of groundwater, sourced mainly from four hydrological basins (the North Central Plateau, Western Highlands, Eastern Highlands, and Uri Plateau) and major rivers such as the Niger and Benue [26]. Despite this, the country faces economic water scarcity due to inadequate investment and weak management, resulting in unmet demand projected to rise from 5.93 billion cubic meters in 2021 to 16.58 billion cubic meters by 2030 [26, 27].
To address these challenges, government initiatives like the Expanded WASH Strategy (2016–2030) and the National WASH Sector Revitalization Action Plan (2018–2022) have been introduced, alongside a Presidential State of Emergency declaration for the WASH sector [28]. However, funding gaps persist, with only 17% of health sector ($14 million of $83 million) and 1% of WASH sector funding ($612,000 of $92.7 million) met as of August 2021 [7].
Also, frequent power outages limit pipe-borne water supply, forcing reliance on poorly constructed wells that are often contaminated, especially where pit latrines are close to water sources [29]. During droughts, dependence on shared, unsafe water sources increases cholera risk, while rising sea levels exacerbate water quality through saltwater intrusion [30].
Sanitation and hygiene
Sanitation remains a significant challenge in Nigeria, where only 33% of the nearly 200 million population have access to adequate facilities [31]. The World Bank estimates that inadequate sanitation results in an annual economic loss of about N455 billion, equivalent to 1.3% of GDP [31]. Poor environmental sanitation has been a major contributor to waterborne diseases, including cholera [31]. Studies in Southern Nigeria’s urban areas reveal widespread reliance on open defecation due to lack of infrastructure [31]. In 2018, over 60 million Nigerians lacked basic drinking water access, and poor water and sanitation conditions contributed to more than 70,000 deaths annually among children under five [31]. The 2019 National Outcome Routine Mapping of WASH Services (WASHNORM) reported that only 44% of Nigerians had proper sanitation access, with just 16% having safe hygiene facilities [31].
Historical cholera outbreaks have been linked to poor sanitation and contaminated water. For example, in 1982, a water shortage in Katsina forced residents to use contaminated abandoned wells [29], while the 1995–1996 Kano outbreak was traced to unsafe water sold by street vendors, underscoring the need for improved water safety measures [19]. Point-of-use water treatment interventions such as chlorination and safe water storage could have lessened outbreak severity [19].
However, efforts to address sanitation challenges have been initiated, including the USAID-funded WASH program in Kebbi, Sokoto, and Zamfara, with a budget of $9.98 million in the year 2021 [31]. The World Bank has committed $700 million to the Nigeria Sustainable Urban and Rural Water Supply, Sanitation, and Hygiene Program (SURWASH) in 2020 to provide 6 million people with basic drinking water and 1.4 million with improved sanitation services [3124]. The World Bank, in collaboration with its partners, has backed the National Urban Water Sector Reform Program (NUWSRP) to expand access to safe drinking water by establishing more than 2,300 water points and 6,546 sanitation units throughout Nigeria [31]. Despite these efforts, reports show that most Nigerians still do not have access to clean drinking water and proper sanitation services, necessitating continued investments and policy reforms [31]. A complicated humanitarian catastrophe has also been brought about by the ongoing conflict in Northeast Nigeria, which has limited the implementation of WASH initiatives and caused the Lake Chad basin, the region’s main water source, to diminish, making it more difficult to reach some towns [32]. Therefore, it is crucial to close the gap caused by the lack of potable water as well as basic facilities and services for the safe disposal of human wastes like urine and feces if Nigeria is to win the fight against infectious illnesses like cholera [31].
Impact of climate change and extreme weather events on cholera outbreaks
Climate change is a major factor driving cholera outbreaks in Nigeria, as extreme weather events like floods and droughts disrupt water and sanitation systems, facilitating disease transmission [16]. Studies in Katsina’s Funtua area have shown a link between rising temperatures, increased rainfall, and cholera incidence, with outbreaks peaking in August [33]. Research in Kano and Ebonyi States similarly indicates higher case numbers during the rainy season [20, 21]. A wider analysis across Sub-Saharan Africa confirms that cholera outbreaks often peak with heavy rainfall and flooding [34]. However, regional variations exist within Nigeria; in northern areas such as Kano, outbreaks typically coincide with the rainy season, while in southern Calabar, cholera is more common during the dry season and declines when rains begin [1, 18]. These patterns suggest that although seasonality affects cholera transmission, outbreaks can occur throughout the year, making their timing in Nigeria less predictable [1, 35].
Impact of flooding
Flooding has played a significant role in cholera outbreaks in Nigeria. In 2010, severe floods in northern Nigeria displaced approximately 258,000 people, heightening cholera risk due to contaminated water and inadequate sanitation [2]. The floods in Anambra, Kogi, and Niger States in 2018 were also linked to increased cholera transmission and higher case fatality rates [23]. Likewise, the 2022 outbreak in northern Nigeria was primarily attributed to widespread flooding [25]. In 2024, Nigeria saw more rainfall than usual, with extended and heavy downpours that caused extensive flooding in a number of states, notably Adamawa, Borno, and Yobe. A favorable environment for the spread of cholera is created when flooding overwhelms water systems and contaminates drinking water sources with Vibrio cholerae from sewage and other waste materials [30]. Furthermore, the bacterium thrives in stagnant floodwaters, which increases its spread during months with the highest rainfall [36].
Role of rainfall and temperature variability
Statistical analyses indicate that increased rainfall and rising temperatures create favorable conditions for Vibrio cholerae proliferation [33]. In Katsina State’s Funtua area, cholera cases peaked during July to September, coinciding with the heaviest rainfall [33]. Similar patterns were observed in Kano and Ebonyi States, where higher temperatures and rainfall correlated with increased cases [16]. Intense rainfall causes flooding, damages pit latrines, and contaminates water sources, thereby facilitating cholera transmission [33]. Historical data show relatively low cholera incidence from 1985 to 1993, followed by a rise from 1994, peaking in 2013 [33]. Notably, cases were lowest during the severe droughts of the 1980s, underscoring the link between rainfall and outbreaks [33]. The 1996 outbreak deviated from typical seasonality, with peaks in early and late rainfall periods, highlighting the role of seasonal transitions in cholera dynamics [37]. Climate variability and rising temperatures also increase air pollution and extreme weather events, promoting cholera spread through contaminated water and food [33]. Unchecked climate change may expand cholera to new regions, disproportionately impacting vulnerable populations with low immunity [33].
According to data from the Nigeria Meteorological Agency (NiMet), rainfall levels in northern Nigeria rose by 18% during the 2022 rainy season when compared to the 10-year average. In Kano and Jigawa states, which together recorded more than 5000 cholera cases during the same time period, this precipitation rise led to catastrophic flooding [38]. These outbreaks, which made up about 40% of the total nationwide, showed a direct correlation between the frequency of cholera and extreme rainfall. According to a retrospective analysis of cholera outbreaks from 2015 to 2020, months with average temperatures above 30 °C saw a 22% increase in cholera cases. Particularly in semiarid areas like Borno and Yobe, which frequently record high cholera rates during peak hot seasons, this temperature range improves Vibrio cholerae’s survival and multiplication in water sources [36]. States that experienced floods, such as Lagos, Bayelsa, and Adamawa, had cholera case fatality rates (CFR) of up to 4.5%, while the national average was 3.2% [39].
Conflict and displacement: impact of regional conflicts and population displacement on cholera spread
Conflict-induced displacement has played a major role in exacerbating cholera outbreaks in Nigeria, particularly in the northeastern and northwestern regions [7]. Poor cleanliness, frequent travel, and congestion exacerbate the spread of disease in places going through internal crises like social displacement and conflict. These difficulties are made worse by inappropriate waste management and limited access to necessities like sanitary restrooms, potable water, and wholesome food, which increases instability and health hazards [40].
Case studies of cholera outbreaks in conflict zones
Maiduguri, Borno State (2015): A cholera outbreak in IDP camps resulted in 385 cases and 13 deaths (CFR: 3.4%) due to poor sanitation and movement between the camps and surrounding communities [25].
Borno State (2017): The outbreak predominantly affected IDP camps, with 5,889 cases reported across five local government areas (LGAs), leading to an overall attack rate of 395.3 per 100,000 population [25]. The CFR was 0.87%, with the highest mortality rate among individuals aged 60 years and above [25]. The destruction of critical infrastructure, including health facilities, sanitation systems, and water supplies, exacerbated the crisis [25]. Muna Garage IDP camp was the outbreak’s initial focal point, from where it spread to other LGAs [25].
Adamawa State (2022): Six LGAs, including Yola, reported 135 cases and seven fatalities, with temporary population displacement contributing to water contamination [7]. Yobe State recorded 1,300 suspected cholera cases across 12 LGAs, but no official outbreak declaration was made [7].
Northern Nigeria (2022): Cholera outbreaks were driven by flooding and ongoing conflicts [25]. Over 10,000 probable cases were reported between June and September, with Borno State accounting for 70.13% of the 7,700 cases and 324 deaths across Borno, Adamawa, and Yobe states [25]. Conflict-induced displacement led to limited access to clean water, increased hospitalizations, and a high mortality rate [25].
Northwestern Nigeria (2022): Armed conflicts displaced 455,000 individuals across Katsina, Zamfara, and Sokoto states, with Zamfara and Katsina hosting the highest numbers of IDPs [7]. Kaduna State recorded 196 cholera-related deaths in 2022, highlighting the direct link between insecurity and cholera outbreaks [7].