African camels show MERS virus more widespread than believed.

Mystery disease: a man wearing a mask at a camel market in al-Thamama, Saudi Arabia. Photo: Reuters

May 20, 2014, Geneva (The Sydney Morning Herald): The deadly respiratory virus that has spread from Saudi Arabia around the world was found in camels in Nigeria, Tunisia and Ethiopia, showing the pathogen is more widespread than previously known.

Middle East respiratory syndrome coronavirus, or MERS-CoV, was found in almost all blood samples taken from 358 dromedary camels in Nigeria and 188 camels in Ethiopia, according to a study published online by the Emerging Infectious Diseases journal. In Tunisia, MERS-CoV was found in 54 per cent of adult camels, and in all of the animals from one southern province.

The findings add to previous studies that have found the virus in camels in Spain’s Canary Islands and Egypt, as well as in several nations on the Arabian Peninsula, and suggest that there may be undiagnosed human cases in Africa, researchers from the Netherlands wrote in the study.

The blood samples were collected between 2009 and 2011, suggesting the virus was circulating well before 2012 when the first human case was identified, they said.

“The possibility exists that MERS-CoV illness occurred before its discovery in 2012 and that such infection has been overlooked in the areas with evidence for virus circulation among animals during the past 10 years,” the authors wrote in the journal, published by the US Centers for Disease Control and Prevention.

MERS has sickened at least 614 people, killing 184 of them since 2012, according to the World Health Organisation. While most of the cases and deaths have been in Saudi Arabia, there have been infections in Europe, Africa, Asia and the United States. All cases are linked to people who live in or have travelled to the Middle East, or who were exposed to someone who did.

The WHO’s emergency committee last week decided against declaring MERS a global health emergency, citing the lack of evidence for sustained human-to-human transmission. Most of the infections have been because of poor infection-control practices in hospitals, the WHO said.

MERS causes fever, cough and shortness of breath, leading in severe cases to respiratory failure, organ failure and death. People with weakened immune systems such as the elderly and those with diabetes, cancer or chronic lung disease are most at risk. There is no vaccine and no specific treatment.

The potential route of transmission from camels to humans isn’t well understood. Many cases of the illness have occurred among camel herders and people who visited camel farms or consumed unpasteurised camel milk.

The virus belongs to the same family of pathogens as SARS, which killed about 800 people worldwide after first appearing in China more than a decade ago.

Saudi Arabia expects millions of Muslims from around the world to perform the annual Hajj pilgrimage to Mecca and Medina in early October. The WHO doesn’t recommend any travel restrictions related to MERS, though Saudi Arabia has suggested that pilgrims over 65 years or under 12, and pregnant women, refrain from the journey.