

Millions of pilgrims headed for the annual Hajj pilgrimage this year in Saudi Arabia could be exposed to a cholera outbreak that has swept through Yemen, the World Health Organisation said on Friday.



The disease, which has already infected 332,000 people in Yemen, raises the risk of infection at the gathering in Mecca, where pilgrims are already wary of diseases such as dengue, yellow fever and Zika virus, the WHO said.



The pilgrimage draws around 2 to 4 million people each year.

"The current highly spreading outbreak of cholera in Yemen - as well as in some African countries - may represent a serious risk to all pilgrims during the (Hajj) days and even after returning to their countries," a WHO bulletin said, according to Reuters.

WHO cholera expert Dominique Legros said Saudi Arabia has avoided cholera outbreaks for many years due to reinforced surveillance and early detection.

"Don't forget that today we are speaking of Yemen but they are receiving pilgrims from a lot of endemic countries, and they managed not to have an outbreak, essentially by making sure that living conditions, access to water in particular, hygienic conditions, are in place," Legros told a UN briefing group.



Cholera, which spreads by the ingestion of faecal matter, has an incubation period of a few hours. The disease can kill an infected person within hours if symptoms are not treated.



However, the fact that 80 percent of patients show no symptoms has made it harder for health agencies to contain the disease, Legros said.

"That's why we advise countries against airport screening for patients. The Saudis don't do that. It's useless, technically speaking," he said.

The highly contagious disease is treatable, but the collapse of Yemen's infrastructure following more than two years of a Saudi-led war against Houthi rebels in the country has created a "perfect storm for cholera", the World Health Organisation has said.

The war has left less than half of the country's medical facilities functional, with aid groups diverting funding from fighting malnutrition to battle the disease – raising the risk of famine.