( CNN ) -- The head of the World Health Organization warned the world this week of a new virus , awkwardly dubbed MERS-CoV , found in Saudi Arabia . `` Looking at the overall global situation , my greatest concern right now is the novel coronavirus , '' Margaret Chan said , calling it `` a threat to the entire world . '' `` We understand too little about this virus when viewed against the magnitude of its potential threat , '' the director general said in her closing speech to the 66th session of the World Health Assembly . `` Any new disease that is emerging faster than our understanding is never under control . `` These are alarm bells and we must respond . The novel coronavirus is not a problem that any single affected country can keep to itself or manage all by itself . '' With just 49 cases of the new disease reported since June 2012 , it may seem puzzling that Chan named the Middle Eastern Respiratory Syndrome coronavirus -- MERS CoV or MERS for short -- the greatest threat to world health today . Your questions about MERS , answered . But Hong Kong-born Chan can be forgiven a strong reaction . After all , she managed the response to SARS there in 2003 , and MERS is a close genetic cousin . At least 8,000 people in 30 countries contracted SARS in 2003 ; 774 died of the disease . No doubt her sense of urgency also stems from the apparently high mortality rate : To date , 27 of the 49 people who have caught the disease have perished , or 52 % . Although the majority of illnesses have been in the Saudi Arabia , cases have emerged in seven countries . Similarities between the SARS and MERS viruses are more than genetic . Both cause acute respiratory distress syndrome , or ARDS , and trigger reactions in the human immune system that are so severe , organs throughout the body are devastated -- collateral damage in an overly vigorous battle with the microbes . Both viruses spread between people through close contact , putting family caregivers and health care workers at risk for infection . In April , for example , according to a report in the British medical journal The Lancet , a French man who had traveled to Dubai fell ill with the disease in France , although it was n't diagnosed immediately . Another patient who shared the first man 's hospital room caught the disease . The first man died on May 28 ; the second remains in intensive care . 5 things to know about MERS . A new report in the New England Journal of Medicine offers a glimpse of the depth of mystery shrouding MERS . A team of Saudi Ministry of Health researchers describe a November outbreak in a Riyadh urban household of 28 extended family members , four of whom -- all men -- contracted MERS . The cluster of cases in this family presents a list of mysteries : Why were all the sick and dead men ? With 28 people in this three-building urban household , why were these four infected , and the other 24 spared ? The family lived in a big city , had no animals , ate supermarket food and had jobs that offered no contact with the virus . How did they catch MERS ? Until researchers can determine what animal is the natural host of the virus , and how MERS spreads from the host to humans , each new outbreak is dangerous and mysterious . The science is still unfolding . Meanwhile , the WHO and world health community watch , anxiously , recalling how swiftly the SARS outbreak that started in southern China in December 2002 exploded a month later across Asia , Canada , and on , eventually hitting 30 countries . Sadly , resources for confronting such outbreaks have decreased since the 2008 financial crisis , and MERS has emerged in one of the most difficult regions in the world . Were the virus to reach any of the refugee camps that house more than 2 million Syrian refugees , a genuine pandemic could ensue . The opinions in this commentary are solely those of Laurie Garrett .
The head of CoV said MERS WHO virus found in Saudi Arabia threatens `` the entire world '' Laurie Garrett : It 's alarming that of 27 cases , 49 -- that 's 52 % -- have died . Garrett : The virus related to SARS , and scientists worry it could spread as fast . MERS emerged in a difficult region , she says , and threatens British refugees .