Haiti after Hurricane Matthew: Can a cholera epidemic be avoided?

A million doses of cholera vaccine are on their way to Haiti's most vulnerable

The World Health Organization (WHO) is sending a million doses of cholera vaccine to Haiti, where more than 200 cases of the killer disease have been reported since Hurricane Matthew struck on 4 October.

A race is on to curb new outbreaks before the imminent rainy season makes toilets overflow, helping cholera to spread.

"The top priority, clearly, for those people affected by the hurricane is to give them access to safe water. That's the only way we can control cholera," Dr Dominique Legros, a WHO expert, said on Tuesday.

Cholera killed around 10,000 people in Haiti after the devastating 2010 earthquake, when UN peacekeepers introduced it to the country by emptying toilet waste into the Meille River, a major water source.

Now the same communities face another mass tragedy. So what can be done to stop the epidemic?

Vaccinate the public

The UN estimates that 1.4 million Haitians are in need of aid

The WHO wants to give Haitians an oral vaccine, which is taken in liquid form. Usually, patients get a double dose. But in this case a single dose may be used to cover twice as many people - a million instead of 500,000.

"So far, we have one experience of a large-scale campaign with a single dose - it was done in Bangladesh two years ago. It proved effective for six months," Dr Legros said.

But Dr Jean-Luc Poncelet, who is the Pan American Health Organization (PAHO) and WHO representative in Haiti, warns the vaccine is not a complete solution.

"It's only 65% effective. So 35 out of 100 people could still get cholera," he told the BBC.

While immunity is one factor, people in high-risk areas urgently need clean water so they are not exposed to the bacteria in the first place.

Chlorine for safe water

Cholera can spread quickly when sewage ends up in the water supply

Cholera spreads rapidly when sewage is not treated, hygiene is poor and drinking water is unsafe.

To combat these issues, Dr Poncelet says chlorine should be used to sterilise water both at its source and in people's kitchens.

"You can chlorinate the wells," he explains. "The distribution systems that do exist must be chlorinated every single day of the year. A well can be treated with chlorine, and if it is sealed properly, that well can be perfectly protected."

At home, Haitians can kill deadly bacteria by putting a few drops of chlorine in the water they use. It's an affordable solution, as a month's supply for a family of six costs around 85 US cents.

Unicef says that before the hurricane, only one in three people in Haiti had access to proper latrines, and under three in five had safe water. In rural areas, this drops to one in four for toilets and just one in two for water.

Dr Poncelet says awareness campaigns can encourage people to adopt safer habits, especially regular hand-washing.

Cholera can be lethal, but isn't actually as deadly as many people believe. With rapid treatment, many sufferers recover.

Keeping cholera patients alive

A patient receives treatment for cholera after Hurricane Matthew at a hospital in Les Anglais

Cholera patients need to be rehydrated - and if this happens promptly, fewer than 1% will die.

Most patients can be successfully treated with an oral rehydration solution, to replace the fluids and salts lost to diarrhoea and vomiting. Very sick people may also be put on an intravenous drip.

The WHO advises that while antibiotics can reduce the length and severity of the illness, rehydration is the single most important thing.

Read more about Haiti:

Hurricane-ravaged Haiti mourns dead

Haiti at risk of 'real famine'

Haitians describe Hurricane ordeal

Cause for optimism?

Hurricane Matthew killed at least 1,000 people in Haiti and left 1.4 million in need of aid - including hundreds of thousands who lost their homes and crops. The United Nations (UN) has called for $120m (£98m) in emergency funds, and aid agencies are rushing to boost relief efforts on the ground.

Chlorine tablets are not hard to transport, but much will depend on getting them over damaged roads and bridges to stricken parts of Haiti's battered southern peninsula.

Dr Poncelet insists that despite the challenges ahead, Haiti need not be doomed to another huge cholera death toll.

"I am quite optimistic," he told the BBC. "The most likely scenario is an increase in the number of cases. The rainy season from October-January sees an increased number.

"But for the first time we have access to vaccines in a larger number - a million from the global stock. That will not solve the problem, but it's an additional tool we did not have in the past.

"If we really work in a co-ordinated fashion, then we should avoid the massive epidemic of 2011."