Health warnings have been issued to people whose homes have been flooded as more areas are hit by torrential rain.
Crossgar has been badly hit by the torrential rain
Parents have been urged to stop children playing in flood water in case they contract diseases. Raw sewage is present in many flooded areas.
However, the chief medical officer has said the major health hazard of floods comes from all the stress and strain of the event, not infection.
Dr Michael McBride has issued advice for people cleaning up after flooding.
Experience from previous flooding and sewage contamination showed that any risk to health was small, he said.
"Booster immunisations or antibiotics are not usually required.
"Harmful gut bacteria such as E. coli O157 may be present in sewage and animal slurry, and this can pass into flood water, although there is likely to be substantial dilution and therefore the risk to health is low."
Dr McBride said people should not eat any food that had been covered by or come into contact with floodwater.
Remove dirty water and silt from property
Wash hands with soap and clean water
Use of protective clothing
Wash clothing and bedding at high temperature
Food preparation surfaces should be wiped down
Caterers should seek detailed advice
"Ensure all surfaces that food will come into contact with are sound and disinfected.
"Particularly make sure that the shelves including those in your refrigerator where food is stored are cleaned and disinfected."
Following Tuesday's flooding, there were reports of rats being seen in parts of east Belfast.
In developing countries, leptospirosis (Weil's disease carried by rats) can follow flooding, but has not been commonly detected in the UK.