Hopes of stopping Haiti's cholera outbreak from turning into an epidemic were fading yesterday, as the disease has begun to infect residents of the densely populated tent cities of Port-au-Prince, where more than a million homeless people are still living as a result of January's earthquake.
Health officials confirmed their worst fears of the disease spreading to the capital, when tests revealed that it had infected a three-year-old boy from the Cite Soleil neighbourhood who hadn't left the city since cholera was first recorded in Haiti just over a fortnight ago.
Previously, the handful of cases in Port-au-Prince came from citizens who had recently arrived there from the mostly rural central region, where the current outbreak is thought to have started at the end of October.
Nationwide, the official death toll has now passed 500, and reports coming in from small towns around the country suggest that many hospitals are struggling to cope with the influx of victims of the water-borne disease, which causes severe diarrhoea and can kill through dehydration in a matter of hours.
In Raboteau, a seaside slum in the north of the country, rubbish trucks were patrolling the streets clearing up unclaimed bodies.
Doctors had run out of rehydration drips, so were referring patients to the hospital in Gonaives, where a reporter from the Los Angeles Times spoke of scores of patients lying outside on stretchers, expelling diarrhoea "clear as water" into buckets.
Haiti's Health Ministry has announced a state of emergency, saying the disease poses a threat to the security of the nation's entire population of just under 10 million. They urged citizens to observe basic hygiene rules, and not to drink unpurified water.
"Now it is our duty as citizens to help solve this problem, which has gone from being an urgent humanitarian matter to the level of national security," said the ministry's executive director, Dr Gabriel Timothee, in a televised news conference yesterday.
According to official figures, there have been 544 deaths and 8,000 cases of the disease since it was first identified on 27 October.
However those numbers are likely to be out of date, since it takes several days of laboratory tests to confirm each case, meaning they underestimate the scale of the outbreak.
At the La Piste camp in Port-au-Prince, Amanda George, an aid worker from the British Red Cross, said her medical team had already treated roughly 40 people who were suspected of having cholera.
"A couple of days ago, we saw the first ones arrive in our observation centre," she said.
"We haven't heard back from the lab, but we just know it's cholera. We've got people losing fluids everywhere. Some of the patients, particularly children, look very ill. Their eyes have rolled back and they have white pupils from dehydration."
The return of the disease, eliminated from Haiti 30 years ago, adds yet another problem to the list affecting the nation, which lost almost 300,000 people in January's earthquake.
It could also pose a logistical challenge to the authorities hoping to organise the scheduled Presidential elections on 28 November, although the UN said yesterday that it still intends to make sure the vote goes ahead.