REUTERS - The deadly MERS virus remains a serious public health problem, especially with the approach of the Muslim hajj pilgrimages to Saudi Arabia, but a recent surge in cases of the respiratory disease appears to be abating, the World Health Organization said on Tuesday.

The Middle East Respiratory Syndrome virus, which causes coughing, fever and sometimes fatal pneumonia, has been reported in more than 800 patients, mainly in Saudi Arabia.

It has spread to neighboring countries and, in a few cases, to Europe, Asia and the United States. At least 315 people worldwide have died from the disease.

In a statement issued after the 6th meeting of its MERS emergency committee, the WHO said a surge in cases in Saudi Arabia that began in April has now decreased and "there is no evidence of sustained human-to-human transmission in communities".

"There have been significant efforts made to strengthen infection prevention and control measures," it said. As a result, "the committee unanimously concluded that the conditions for a Public Health Emergency of International Concern (PHEIC) have not yet been met".

Global health regulations define a PHEIC as an extraordinary event that poses a risk to other WHO member states through the international spread of disease, and which may require a coordinated international response.

The WHO stressed, however, that the MERS situation continued to be "of concern," especially given an anticipated increase in travel to Saudi Arabia related to the pilgrimages and religious festivals of Umra, Ramadan and the hajj.

The WHO's assistant director general for health security, Keiji Fukuda, said the committee had urged vulnerable countries, especially those in Africa, to take concrete action ahead of Umra, Ramadan and hajj, with basic public health measures such as conducting surveillance for MERS, raising awareness about it and implementing basic infection prevention and control measures.

Millions of people travel to Mecca each year for the hajj, the pilgrimage which all Muslims must perform at least once in their lifetime, if they are able. This year's will take place in October.

MERS has been linked to camels, which many scientists think may be a major source of infection in people. Hundreds of new MERS infections were contracted by patients and health workers in hospitals in Saudi Arabia during recent months.

But Fukuda said he was now confident Saudi authorities were taking MERS very seriously and working hard to control it.

"The Saudi government has made an extensive effort really to catch up on all the numbers and to provide them as quickly as possible," he told reporters on a teleconference from the WHO's Geneva headquarters. "I see a big amount of improvement taking place."