All six cases are linked to either Saudi Arabia or Qatar. One person has been flown to the United Kingdom for treatment.
It is believed that the virus does not pass readily from person to person.
Coronaviruses are a family of viruses ranging from the common cold to the SARS (severe acute respiratory syndrome) virus. They infect a wide range of animals.
In 2002 , 800 people were killed after an outbreak of the SARS coronavirus that spread from Hong Kong to more than 30 countries across the globe.
Research is being done by the WHO to identify where the infection came from. Recent studies show that the virus is closely related to that found in some species of bats.