Middle East respiratory syndrome

Middle East respiratory syndrome (MERS), also known as camel flu, is a viral respiratory infection caused by the MERS-coronavirus (MERS-CoV). Symptoms may range from mild to severe. They include fever, cough, diarrhea, and shortness of breath. Disease is typically more severe in those with other health problems. Mortality is about one-third of diagnosed cases. MERS-CoV is a betacoronavirus derived from bats. Camels have been shown to have antibodies to MERS-CoV but the exact source of infection in camels has not been identified. Camels are believed to be involved in its spread to humans but it is unclear how. Spread between humans typically requires close contact with an infected person. Its spread is uncommon outside of hospitals. Thus, its risk to the global population is currently deemed to be fairly low. As of 2016 there was no specific vaccine or treatment for the disease; a number of antiviral medications were being studied. The World Health Organization recommends that those who come in contact with camels wash their hands frequently and do not touch sick camels, and that camel-based food products be appropriately cooked. Treatments that help with the symptoms may be given to those infected. Just under 2000 cases have been reported as of April 4, 2017. About 36% of those who are diagnosed with the disease die from it. The overall risk of death may be lower as those with mild symptoms may be undiagnosed. The first identified case occurred in 2012 in Saudi Arabia and most cases have occurred in the Arabian Peninsula. A strain of MERS-CoV known as HCoV-EMC/2012 found in the first infected person in London in 2012 was found to have a 100% match to Egyptian tomb bats. A large outbreak occurred in the Republic of Korea in 2015. Early reports compared the viruses to severe acute respiratory syndrome (SARS), and it has been referred to as Saudi Arabia's SARS-like virus. The first person, in June 2012, had a 'seven-day history of fever, cough, expectoration, and shortness of breath.' One review of 47 laboratory confirmed cases in Saudi Arabia gave the most common presenting symptoms as fever in 98%, cough in 83%, shortness of breath in 72% and myalgia in 32% of people. There were also frequent gastrointestinal symptoms with diarrhea in 26%, vomiting in 21%, abdominal pain in 17% of people. 72% of people required mechanical ventilation. There were also 3.3 males for every female. One study of a hospital-based outbreak of MERS had an estimated incubation period of 5.5 days (95% confidence interval 1.9 to 14.7 days). MERS can range from asymptomatic disease to severe pneumonia leading to acute respiratory distress syndrome (ARDS). Kidney failure, disseminated intravascular coagulation (DIC), and pericarditis have also been reported. Middle East respiratory syndrome is caused by the newly identified MERS coronavirus (MERS-CoV), a species with single-stranded RNA belonging to the genus betacoronavirus which is distinct from SARS coronavirus and the common-cold coronavirus. Its genomes are phylogenetically classified into two clades, Clades A and B. Early cases of MERS were of Clade A clusters (EMC/2012 and Jordan-N3/2012) while new cases are genetically different in general (Clade B). The virus grows readily on Vero cells and LLC-MK2 cells. A study performed between 2010 and 2013, in which the incidence of MERS was evaluated in 310 dromedary camels, revealed high titers of neutralizing antibodies to MERS-CoV in the blood serum of these animals. A further study sequenced MERS-CoV from nasal swabs of dromedary camels in Saudi Arabia and found they had sequences identical to previously sequenced human isolates. Some individual camels were also found to have more than one genomic variant in their nasopharynx. There is also a report of a Saudi Arabian man who became ill seven days after applying topical medicine to the noses of several sick camels and later he and one of the camels were found to have identical strains of MERS-CoV. It is still unclear how the virus is transmitted from camels to humans. The World Health Organization advises avoiding contact with camels and to eat only fully cooked camel meat, pasteurized camel milk, and to avoid drinking camel urine. Camel urine is considered a medicine for various illnesses in the Middle East. The Saudi Ministry of Agriculture has advised people to avoid contact with camels or wear breathing masks when around them. In response 'some people have refused to listen to the government's advice' and kiss their camels in defiance of their government's advice. There has been evidence of limited, but not sustained spread of MERS-CoV from person to person, both in households as well as in health care settings like hospitals. Most transmission has occurred 'in the circumstances of close contact with severely ill persons in healthcare or household settings' and there is no evidence of transmission from asymptomatic cases. Cluster sizes have ranged from 1 to 26 people, with an average of 2.7.