A cholera epidemic that began last month is sweeping through the coastal cities of Sierra Leone and Guinea, killing hundreds and affecting tens of thousands more. The disease has claimed at least 244 lives and infected over 14,000 people in Sierra Leone alone. In neighbouring Guinea more than 100 have died and thousands more are sick. The outbreak is more severe than usual due to recent heavy rains which dramatically increased the spread of the disease.

The hardest hit have been those in the overcrowded slums of the two countries' capital cities, areas that lack clean water and basic sanitation services. "It is expected to get a lot worse before it gets better," warns Claire Seaward of Oxfam Sierra Leone.

International aid has begun to trickle in, but much more is needed to address this crisis and the fundamental problems that allow a disease like cholera to become epidemic in the region.

National emergency

Cholera is a devastating infection of the small intestine that, if left unattended, can kill in a matter of hours. It is spread through contaminated feces, making it particularly deadly in these two poverty-stricken nations where roughly two-thirds of the population live without toilets.

Cholera isn't new to the area, but Sierra Leone and Guinea have been largely spared from the devastation in the past. The largest recorded outbreak was in 1994, when 10,000 people were infected in Sierra Leone. This record was surpassed last week and the number is still climbing.

Over the past year, cholera has become increasingly deadly in the broader western and central African region. In 2011 it killed over 2,000 people and infected roughly 85,000. Despite the region's familiarity with the disease, this recent outbreak has officials in Sierra Leone worried. They have now classified it as a national emergency.

"All of this is the aftermath of the 11 years rebel war when we had a huge rural-to-urban migration and a huge population clustered in the urban area where adequate provision has not been made for water and sanitation. This is what we have been witnessing today," said Sierra Leone's minister of health and sanitation, Zainab Hawa Bangura, when speaking to the Associated Press.

Cholera is preventable

For the moment, emergency workers are simply trying to keep people alive. But as Charles Gaudry of Doctors Without Borders points out, treatment and vaccination alone will not solve this problem: "In-depth work on water and sanitation networks is the only way of controlling the disease in the long term."

The International Federation of Red Cross and Red Crescent Societies (IFRC) echoes this, warning that this outbreak could spark a much larger regional crisis if the underlying infrastructure problems, particularly overcrowding, poor sanitation and safe water access, aren't more aggressively tackled.

Efforts are under way to provide this infrastructure, but progress is slow. The UK has mobilised an emergency response, as has the IFRC, but both cite a lack of funds as one of the major stumbling blocks to addressing the root causes of cholera.

Sanitation may not be the sexiest international issue, but it can mean life or death for those living in urban slums. Without proper sanitation, cholera is nearly impossible to stop.

Learn more: The Guardian has an excellent article on the power of toilets to save lives. And you can help with the emergency relief efforts by donating to Doctors Without Borders, one of the first organisations on the ground providing medical assistance.

Sources: Associated Press, News24, Telegraph, New York Times, Al Jazeera, Doctors without Borders, IFRC, BBC, IRIN, Guardian