Some 700,000 suspected cases of cholera have hit Yemen, with the outbreak showing no signs of rescinding, the WHO has reported.
In its plan to tackle the disease, the organisation has planned to distribute vaccines to contain cholera and eradicate 90 per cent of cases by 2030.
"Once it's out of the box, once it has spread, it's very, very difficult to contain and we have a huge number of cases and deaths," said Dominique Legros of the WHO's department for pandemic and epidemic diseases.
"It spreads like a forest fire," Legros continued.
The official account of cases cannot be verified, as many may transpire to have contracted acute watery diarrhoea instead.
Yemen has been in a state of civil war since 2014, when Iranian-backed Houthis overtook swathes of territory from north of Yemen to the capital, Sana'a.
A Saudi-led coalition entered the civil war to reinstate President Abd Rabbuh Mansur Hadi's governance and push back military advancements by the Houthi group.
Impoverished Yemen is enduring a brutal civil war, dire humanitarian crisis and an uncontrollable cholera outbreak.
According to UN officials, more than 10,000 people have been killed in the war, while more than 11 per cent of the country's population has been displaced.