The floods that have submerged much of Pakistan in recent weeks have killed some 1,500 people and left tens of millions homeless, but the final death toll is likely to be significantly higher. From illness to disruption of health care, floods affect people’s health in a number of direct and indirect ways. Such events are also expected to become more frequent as a result of climate change and sea level rise. So what makes floods so deadly? Is there anything that countries can do to reduce the number of victims?
Flooding can cause widespread damage to crops and livestock, affecting both the quantity and quality of food available.
1. Drowning and acute injury
Floods account for 40% of all natural disasters worldwide and is responsible for about half of associated deaths. Most of these deaths are due to drowning, particularly as a result of people becoming trapped in their vehicles while trying to drive through torrents. Fatalities can also occur if people are struck by fast-moving water, as a result of overexertion, hypothermia, or electrocution, or as a result of being struck by objects caught in flood water, including falling trees. Some of these injuries may not cause death right away, but rather in the days or weeks after the event, such as through wounds that become infected by bacteria in flood water.
Access to clean water is often a major problem after a severe flood. Flooding can cause sewers to overflow, contaminating drinking water and increasing the risk of gastrointestinal illness, while poor hygiene and overcrowded shelters can aggravate the situation.
Recent floods in bangladesh resulted in large outbreaks of bacterial gastroenteritis, particularly cholera and pathogenic E. coli, with cholera outbreaks tending to occur about eight days after the initial flood. Rapid distribution of oral cholera vaccine can help mitigate this risk, although delivering it to flood-affected communities is challenging.
Other illnesses associated with flood events include typhoid fever, hepatitis A and E, rotavirus, and norovirus. Being submerged or inhaling flood water can also lead to lower respiratory tract infections, such as pneumonia, as well as skin or eye disease, or leptospirosis (Weil’s disease), which is spread through contact with rodent urine.
As floodwaters recede, pools of stagnant water can become breeding grounds for mosquitoes, increasing the risk of mosquito-borne diseases such as dengue fever and malaria. There has already been an increase in dengue cases in Pakistan, with at least 3,830 cases and 9 deaths reported by health officials in Sindh province as of September 15, 2022. Health officials also reported an increase in malariadiarrhea and skin diseases after the flood.
3. Poisonous creatures
It’s not just humans who are left homeless by the floods. Wild animals, including snakes and spiders, may seek shelter inside homes, storage sheds, and other buildings, particularly if these have been damaged. Prompt treatment with antivenom is necessary for people bitten by venomous snakes, but flooding can also make treatment difficult to access.
As of August 30, 134 people in Pakistan were reported to have suffered snake bites as a result of the flooding, including a woman in the northwestern province of Khyber Pakhtunkhwa who died unable to access immediate medical care. In addition to death, poisonous snake bites and spider bites can cause lasting disabilities.
4. Interrupted medical care
When Cyclone Ana hit Malawi in late January 2022, it caused widespread flooding in some areas. This resulted in extensive damage to health infrastructure, including clinics, health records, cold chain equipment, drugs, and medical supplies. Many people also lost their regular medications in the floods.
One consequence of such an interruption is the deterioration of the health of people with chronic diseases such as diabetes or cardiovascular disease, with an associated increase in deaths. For example, after the flooding in Florida during the 2004 hurricane season, there was an increase in heart attacks, and doctors reported a deterioration in patients’ blood pressure control.
Flooding can also make it difficult to deliver vaccines, particularly in rural areas where people must travel to access clinics.
Flooding can cause widespread damage to crops and livestock, affecting both the quantity and quality of food available. For example, in parts of South Sudan, the floods of the last three years have meant that many people have been unable to farm their land. Some have also lost livestock to diseases caused by animals grazing in flooded fields and many have turned to foraging for wild foods such as water lilies. Undernutrition or malnutrition remain major threats to health.
6. Psychological trauma
Although it may not be as deadly, the emotional impact of losing your home, belongings, or livelihood lingers long after the flood waters recede. There is also the economic stress associated with rebuilding, which adds to this psychological cost. Mental health problems after floods are often overlooked and not as well studied as the immediate health impacts of floods.
According to research carried out in the UK after widespread flooding during the winter of 2013/14, the prevalence of depression, anxiety and post-traumatic stress disorder (PTSD) remained elevated for at least two years after exposure to the floods. “Our research suggests that support to address long-term damage to housing, sanitation, and utilities caused by flooding may be necessary to reduce mental health risks,” the authors wrote.
in bangladesh, interviews with flood survivors suggested that 57.5% of them experienced suicidal thoughts, while 6% and 2% had planned or attempted suicide, respectively. Suffering from depression, anxiety and PTSD, and experiencing financial problems or economic hardship were among the key risk factors identified.