SARS-like virus MERS has raised the global death toll to 33, the WHO claims.
Spokeswoman Fadela Chaib said the Saudi health ministry had informed the UN agency of three new laboratory-confirmed cases, one of them fatal, and the death of a patient already diagnosed with the disease.
"Globally, from September 2012 to date, WHO has been informed of a total of 58 laboratory-confirmed cases of infection with MERS-CoV, including 33 deaths," Chaib told reporters.
Until last month, the disease was known simply as novel coronavirus, before being renamed Middle East Respiratory Syndrome Coronavirus, or MERS-CoV, as cases initiated in that region.
There have now been 44 confirmed cases in Saudi Arabia, 28 of them fatal, according to WHO figures.
WHO logs cases by country of infection, rather than of death, and its Saudi toll includes one individual who died in Britain.
One person has died in France after being infected in Dubai, and a patient died in Munich, Germany who was transferred there after first being treated in Abu Dhabi.
There have also been two cases in Jordan, both of them fatal. Qatar has seen two, with those patients treated in Britain and Germany.
Two patients caught the disease in Britain from a person who had been to the Middle East, one of whom died.
Tunisia has seen two non-fatal cases and Italy two -- one of whom caught the virus in Jordan and gave it to a contact in Italy.
France has recorded one infection, a man who is thought to have caught the disease while sharing a hospital room with the deceased patient who had got it in Dubai.
The virus is a member of the coronavirus family, which includes the pathogen that causes Severe Acute Respiratory Syndrome (SARS).
SARS sparked global panic in 2003 after it jumped to humans from animals in Asia and killed 800 people.
Like SARS, MERS appears to cause a lung infection, with patients suffering from a temperature, cough and breathing trouble. But it differs in that it also causes rapid kidney failure.
Health officials have expressed concern about the high proportion of deaths relative to cases, warning that MERS could spark a new global crisis if it mutates into a form that spreads more easily.