GENEVA • The wrong diagnosis of a woman suffering from the Middle East respiratory syndrome (Mers) coronavirus led to more than 49 other patients and medical staff being exposed to the disease in a Saudi hospital, the World Health Organisation (WHO) has said.

The unnamed 49-year-old from Buridah city developed symptoms on June 9 and was admitted to hospital on June 10 where she was in a critical condition in an intensive care unit, WHO said in a statement yesterday. On June 12, she tested positive for Mers, a potentially fatal coronavirus from the same family as the one that caused China's deadly 2003 outbreak of the Severe Acute Respiratory Syndrome.

WHO said the woman had initially gone to hospital for a condition unrelated to Mers.

"She was then admitted to the vascular surgery ward - MERS-CoV infection was not considered.

"She was not isolated and was managed in a multi-bed room. During this time, more than 49 HCWs (healthcare workers) and patients were exposed," WHO said.

A rapid response team immediately tried to trace the people with whom she had had contact at her home and in the hospital in Riyadh, and 20 of them tested positive, although 18 of the 20 had no symptoms.

Mers is thought to be linked to camels and consumption of camel milk, but most of the known human-to-human transmission have occurred in healthcare settings.

WHO has said that hospitals and medical workers should take stringent precautions as a standard measure to prevent the disease from spreading.

REUTERS