Many Iraqis have had to use contaminated water
A newly recruited and trained armed police force is to begin guarding water installations in Basra, where there are fears of a cholera epidemic.
This should help prevent looting and damage to plants supplying Basra's water, Colonel John Graham, a senior officer of the British army which controls the city, has said.
Many Iraqis have been unable to get enough drinking water because of the damage caused in the recent war in Iraq and have resorted to using contaminated water.
The World Health Organization (WHO) said on Wednesday it expected a cholera epidemic in southern Iraq because of problems with poor sanitation.
After 17 cases emerged in a 24-hour period, hospital doctors reported on Thursday that they are treating another two patients, both women, aged 70 and 25.
Endemic in Iraq, particularly in hot months
Caused by drinking or bathing in or eating food washed in contaminated water
Incubation period of 2-5
Attacks intestine, causing diarrhoea and vomiting, and dehydration as a result
Can be fatal if untreated
Col Graham said a new armed guard force would be operating within days to help stop looting and damage at water plants supplying the city.
"Over a 10-day period, we are recruiting and training a police force and a guard force and hope that they will be going on to the key installations on Saturday," he said.
"It's fairly amazing to be able to recruit a police force in 10 days."
An emergency meeting of health officials and the British army has been held to discuss the sanitation problems.
The current outbreak is being blamed on disruption and damage to the water supplies caused by the recent conflict in Iraq.
This has led some Iraqis to take drastic measures, says the BBC's Jane Peel in Basra.
Those whose homes are not being supplied with water have been connecting pipes they have acquired themselves to any water supply they can find, which is often contaminated with sewage and rubbish.
Georgio Nembrini of the Red Cross in Basra said it was difficult to warn people of the dangers.
"This is one of the major problems, to tell the people first of all what they should not do and if they're getting sick what they should do," he says.
"This is something which is very important so that people should know that they can be treated and cholera is not something they should die from."
Poor security in the city has also meant some victims have been unable to get to hospitals, and health workers have been unable to get out to them, WHO spokesman Ian Simpson told the BBC.
"There is a real shortage of intravenous fluids and intravenous needles needed to rehydrate people who become dehydrated through cholera," he says.