Following heavy rainfall and flooding in parts of South Africa earlier this year, communities in KwaZulu-Natal, Mpumalanga and Limpopo experienced widespread damage, displacement and disruption to water and sanitation services. Floodwaters and overcrowded temporary living conditions can increase the risk of communicable diseases. NICD experts shed light on diseases to look out for after flooding and how you can protect yourself and loved ones.
Which diseases should the public be aware of after heavy rains and flooding?
Flood disasters result in an increased risk of various diseases including water- and food-borne, respiratory as well as cutaneous infections. These diseases occur as a result of poor hygiene, sanitation and food safety as well as disruption or damage of health infrastructure and services. Overcrowding that may result due to the disruption of housing may also contribute to the spread of these diseases.
Environmental changes that results in the increased breeding of certain vectors such as mosquitoes may lead to increases of vector-borne diseases such as malaria, Rift Valley and West Nile fevers. Flooding has also been associated with the occurrence of leptospirosis that occurs following contact with flood water that has been contaminated by the urine of infected animals.
How does contaminated water after floods affect people’s health, and which illnesses should the public be on alert for after flooding?
Consumption of water that has been contaminated with faeces of infected persons can cause gastrointestinal diseases such as Hepatitis A virus (HAV), enteric fever (due to either Salmonella Typhi or Salmonella Paratyphi A, B or C), shigellosis and cholera. Other pathogens that can cause gastrointestinal diseases following floods include E. coli (especially enterotoxigenic E. coli), rotavirus and norovirus.
What are the common symptoms of each disease, and what should the public do if they suspect they might have contracted it after flooding?
- Water- and food-borne diseases:
- HAV: symptomatic HAV can present with or without jaundice, with the former being more common in persons >15 years. Other symptoms include loss of appetite, fatigue, malaise, nausea, vomiting, abdominal discomfort and diarrhoea. For more clinical features, see here
- Enteric fever: Symptoms of enteric fever include a progressively rising fever that can reach as high as 40 °C, as well as gastrointestinal symptoms. These gastrointestinal symptoms may occur in both children and adults and include abdominal pain or cramps, nausea, vomiting, and diarrhoea. Constipation may also occur, particularly in adults. For more clinical features, see here
- Shigellosis: features of symptomatic disease include fever, headache, malaise, vomiting and watery diarrhoea (bloody if there is colon involvement). For more clinical features, see here
- Cholera: typical symptoms include sudden onset of a diarrhoeal illness including vomiting. The diarrhoea is painless, profuse and watery (“rice water” stools) and can have flecks of mucus. Dehydration occurs rapidly if the disease is untreated and can be fatal. Except in children, fever may not occur.
- Respiratory infections: upper and lower respiratory tract infections may occur following exposure to water-borne pathogens, and contaminants contained in flood water such as toxins and pesticides. Clinical features depend on the severity of the illness and include fever, cough, sore throat and difficulty breathing. Pneumonia following exposure to flood water is usually polymicrobial.
- Cutaneous infections: soft tissue and skin infections can occur as a result of trauma and exposure to contaminated water. Typical bacterial causes of soft tissue and skin infections include Staphylococcus aureus, Streptococcus pyogenes and Pseudomonas aeruginosa. Fungal infections can also occur causing necrotising fasciitis. Other pathogens that have been reported following exposure to flood water include nontuberculous mycobacteria (M. chelonae, M. fortuitum and M. abscessus) as well as less common water-dwelling organisms such as Aeromonas spp. and Vibrio spp.
If any of these diseases is suspected, the individual should seek medical attention immediately.
What health and hygiene measures can the public take to protect themselves from getting sick during and after a flood?
The provision of safe water to affected communities, as well as health education focused on observing hand hygiene and food safety are important.
- Safe water: if the quality of water available for consumption is questionable, purifying the water can be achieved by boiling the water for 1 minute or treating the water with household bleach (1 teaspoon (which contains 5% chlorine) added to 20-25 liters of water, mixed well and left to stand for at least 30 minutes before use).
- Hand hygiene: hands should be washed with soap and clean water
- before, during, and after the preparation of food
- before and after eating
- before and after caring for someone who is ill, particularly if the person had a diarrhoeal illness
- after using the toilet
- after changing nappies or cleaning up a child who has used the toilet
- Food safety: this involves the following:
- separating raw from cooked food
- cooking food thoroughly
- keeping food at safe storage temperatures
- keeping food clean by using clean water for preparation and cooking, as well as using clean raw ingredients
Flooding can disrupt daily life and essential services, increasing the risk of communicable diseases. Staying informed, practising good hygiene, and seeking care early can help protect both individuals and communities.
