After the Floods: The Health Crisis Nobody is Warning You About

The warning has been issued. Prof. Joseph Utsev, Nigeria’s Minister of Water Resources and Sanitation, has advised residents across 33 states to prepare for flooding between now and the end of the year, with the peak risk expected between July and September. The Nigeria Hydrological Services Agency’s 2026 Annual Flood Outlook has identified 14,118 communities […]

The warning has been issued. Prof. Joseph Utsev, Nigeria’s Minister of Water Resources and Sanitation, has advised residents across 33 states to prepare for flooding between now and the end of the year, with the peak risk expected between July and September. The Nigeria Hydrological Services Agency’s 2026 Annual Flood Outlook has identified 14,118 communities across 266 local government areas as being at high risk. If you live in any of these states, this is not a distant government problem. This is a personal health matter, and it is coming with the rains.

Most conversations about flooding focus on drowning deaths and property damage. These are devastating enough. In 2024, floods killed over 1,200 people across 31 states and left 1.2 million more displaced. However, there is a slower, quieter crisis that follows every major flood event. It rarely makes the front page. That is the disease burden. After the waters recede, communities already exhausted and traumatised are hit by waves of illnesses. Many of these could have been reduced, if not prevented entirely, with the right knowledge and choices.

Now, floodwater is not simply “a lot of rain”. By the time it has moved through open drains, waste dumps, streets, and markets, the typical path in cities, it carries live pathogens, sewage, agricultural chemicals, heavy metals, and fuel residue. The water that enters your compound or kitchen is not just wet; it is biologically active. Yet, people wade through it without protection, let children play in it, even use it to bathe, or unknowingly drink from sources it has quietly contaminated. These are the main routes through which flood-related illnesses enter the body.

Cholera is the headline threat, and with good reason. In 2024 alone, the Nigeria Centre for Disease Control recorded nearly 11,000 cases, a 220 per cent increase from 2023, with 359 deaths, a year-on-year rise of 239 per cent. The disease can kill within hours through severe dehydration, and flood conditions reliably set the stage for it every season. Typhoid fever follows a slower arc. It often comes as a week of rising fever and fatigue before most people connect it to flood exposure, by which point many have already self-medicated with the wrong drugs.

Hepatitis A and E, both spread through contaminated food and water, also surge during floods and carry particular danger for pregnant women and anyone immunocompromised. The practical response to these is the same: treat your water, full stop. Boil it to a rolling boil for at least one minute or use purification tablets. You should stock these tablets before the rains peak, not after. If you rely on a borehole or well, treat it regardless of appearance; floodwater infiltrates shallow groundwater faster than most people expect. Avoid food that has been in contact with floodwater, wash your hands with soap before eating, and keep that discipline even when clean water itself feels scarce.

Now, skin and wound exposure is another hazard that people underestimate. Any open cut or scrape in contact with contaminated floodwater is an entry point for bacteria, such as cellulitis, wound sepsis, and worse. Leptospirosis is worth mentioning specifically because it is vastly underdiagnosed here. Caused by bacteria carried in rodent urine, it spreads readily when displaced rats share floodwater with humans. Its early symptoms, such as fever, severe headache, and muscle pain, are easily mistaken for malaria, and it can progress to kidney failure, liver failure, and death without early antibiotic treatment.

If you must enter floodwater, wear rubber boots or, at a minimum, tie plastic bags over your feet. Wash thoroughly with soap afterwards, apply antiseptic to any broken skin, and if you develop fever or muscle pain in the days following, tell your doctor you had flood exposure. That detail alone can change the clinical thinking.

The truth is that flooding equally leaves a respiratory outcome that most public health messaging often ignores. Inundated buildings grow mould within 24 to 48 hours in our climate. The spores are airborne and trigger coughing, wheezing, and asthma attacks, while crowded displacement conditions, including shelters, schools, and church halls, create efficient transmission for respiratory infections generally. So, when water retreats, air aggressively, strip out wet furniture and fabrics fast, and treat affected walls with bleach solution. Keep people with asthma or chronic chest conditions away from the cleanup, or ensure they wear masks.

Here is a word on malaria. Flooding does not just bring water; it leaves behind it weeks of standing water in gutters, old containers, and debris piles, which are ideal Anopheles breeding grounds. Malaria surges reliably in the months after major floods, hitting bodies already weakened by other illnesses. So, clear your surroundings of stagnant water as soon as you can, sleep under treated nets, and resist the urge to self-treat with antimalarials before testing. The overlapping symptoms of malaria, typhoid, and leptospirosis require different treatments.

Now, one dimension that Nigerian public health conversations consistently avoid or ignore is mental health. Displacement, loss of property, death of neighbours, and the sheer uncertainty of flood aftermath cause real psychological harm. This includes acute stress, grief, anxiety, and, in many cases, post-traumatic stress disorder. Children show it in nightmares, bedwetting, and school withdrawal. Adults minimise it because survival feels like the priority. However, untreated distress impairs sleep, weakens immunity, and clouds judgement, compounding every other health risk. Community networks, faith leaders, and community health workers remain the most accessible support in the immediate aftermath of flood crises. In high-risk states, NEMA’s toll-free emergency line, 112, and state emergency management agencies are also available.

It is fair, and even necessary, to mention government failures here. They include inadequate drainage, poor urban planning, and the annual water release from the Lagdo Dam in Cameroon that reliably amplifies flooding along the Benue and Niger river basins. These are structural problems that demand structural answers. However, the distinction between what the government must fix and what each household can control in the meantime is real and worth emphasising.

The families who come through flood seasons with the least health damage are not always the wealthiest; they are often the most prepared. They stored clean water early, kept basic medications at home, and knew which symptoms needed a clinic and which needed only rest. That kind of preparedness is available to more people than currently practise it.

The floods will largely come as predicted. In fact, it is already being experienced in many states. However, what happens in your household is not entirely beyond you. This is, therefore, a call, or maybe a plea, for you to actively prepare to avoid telling stories that touch by the time the floods reach their peak.

Ojenagbon, a health communication expert and certified management trainer, lives in Lagos.