GENEVA : A surge in cases of the deadly MERS virus has receded, but countries must maintain vigilance for the Muslim pilgrimages to Saudi Arabia, worst hit by the disease, the World Health Organisation (WHO) said Tuesday.“The upsurge in cases that began in April has now decreased and there is no evidence of sustained human-to-human transmission in communities,” it said in a statement.However, “the situation continues to be of concern, especially given the anticipated increase in travel to Saudi Arabia related to Umrah, Ramadan and the Haj,” the UN health agency said. The communique was issued after a teleconference of health officials from seven countries where there have been cases of Middle East Respiratory Syndrome (MERS).They were Algeria, Iran, Jordan, the Netherlands, Saudi Arabia, the United Arab Emirates and the United States. MERS has killed 284 people in Saudi Arabia since it first emerged in April 2012, and hundreds more have been infected. Twenty-two countries have reported cases.It is considered a deadlier but less transmissible cousin of the Severe Acute Respiratory Syndrome (SARS) virus that appeared in Asia in 2003 and killed hundreds of people, mostly in China.Close contact with camels has been fingered as the likely source of MERS in humans, according to a preliminary investigation by the WHO.Last year, five million pilgrims visited the kingdom for Umrah and Haj.