More than 3,000 dengue cases have been reported in conflict-ravaged Yemen since March, the World Health Organization warned Tuesday, adding that the actual figure could be far higher.
The Saudi-led air strikes launched in late March have crippled an already weak health infrastructure, and lack of water and sanitation facilities are exacerbating the situation, WHO spokesman Christian Lindmeier told reporters.
"More than 3,000 suspected dengue cases have been reported since March 2015 but the numbers are expected to be considerably higher," he said.
"Some NGOs are reporting more than 6,000 cases, that is double the officially reported cases."
The mosquito-borne infectious disease is endemic in Yemen, the poorest country in the region, and spikes every year between April and August, he said, warning though that the figures were far higher this time around "as a result of the current conflict."
"The crisis has severely impacted access to water and sanitation, preventive and clinical services as well as shelter," he said.
"Hundreds of cases are expected in Aden alone in the coming weeks," he said, referring to Yemen's main port city.
"Access to care has been severely impacted with nearly a 50 percent drop in total consultations in 2015 since the conflict began," Lindmeier said.
Dengue symptoms include severe abdominal pain, persistent vomiting and circulatory system failure. The disease can be fatal.
The spike in the disease comes on top of the violence suffered across the country.
More than 2,600 people have been killed in Yemen since March, according to UN figures, and almost 80 percent of the population -- 20 million people -- are in need of humanitarian aid.
The situation is particularly serious in Aden, where residents have complained of food and water shortages and health officials are warning of the spread of disease.