New virus (MERS-CoV) cases increasing

Another case of Middle East respiratory syndrome coronavirus (MERS-CoV) was confirmed in the Middle East on 12th March: a 68 years old man fell ill in the UAE on 1st March, was hospitalised on 3rd March and is now recovering. He had no contact with any known case but he does own a farm where he has contact with animals, including camels. The other two latest cases occurred in late February in Saudi Arabia. MERS-CoV causes severe acute respiratory illness. The first case was a Saudi national. The virus from this patient was isolated from his lungs in The Netherlands.

Cases of MERS-CoV

MERS-CoV was first confirmed as a new disease in September 2012 and since then there have been 189 cases and 82 deaths in total, although the number of people with a mild version of the illness who do not seek medical attention is unknown. Only three cases have been reported in children under 5 years of age. The WHO has received reports of laboratory-confirmed cases in the Middle East, France, Germany, Tunisia and the UK. In these countries the patients were either transferred for care of the disease or returned from the Middle East and subsequently became ill. In France, Tunisia and the UK transmission of the illness has occurred between people in close contact (either at home or in the work place) who had not been to the Middle East.

MERS-CoV infection can cause very severe pneumonia, septic shock and multi-organ failure resulting in death. It is more likely to be mild in individuals who do not have any underlying conditions. The disease starts with a fever and cough, chills, sore throat, muscle and joint pain, followed by difficulty in breathing and pneumonia. Roughly 33% of the patients also suffered from vomiting and diarrhoea. The incubation period is about 5-14 days before the onset of symptoms.

So far, antivirals have not been successful in treating the disease. Various drugs have been screened in cell cultures but there is no clinical data to support their use in humans. However, research using monkeys has found two promising agents: ribavirin and interferonα-2b.

Where did the virus come from?

Coronaviruses are a large family of viruses causing a range of illnesses in humans, from the common cold to SARS. Viruses of this family also cause a number of animal diseases. MERS-CoV is a type of coronavirus which had not been identified in humans prior to 2012. The MERS-CoV infecting humans is genetically close to coronaviruses found in hedgehogs and bats. A genetic sample from a bat matched 100% with the first human patient. Neturalising antibodies against MERS-CoV or similar viruses, but no viral genetic material, has been described in camels. It is not clear whether the bats can infect the camels or whether humans can be infected by both bats and camels carrying the virus. Data suggests MERS-CoV could have emerged as early as 2009.

Worryingly, there has been an increase in the number of cases with over 60% of the patients being male. This higher number of patients verses females could just be down to low number of cases or something more concerning.

Sources:

http://currents.plos.org/outbreaks/article/state-of-knowledge-and-data-gaps-of-middle-east-respiratory-syndrome-coronavirus-mers-cov-in-humans-2/

http://www.cdc.gov/coronavirus/MERS/

http://en.wikipedia.org/wiki/Middle_East_respiratory_syndrome_coronavirus

http://www.who.int/csr/disease/coronavirus_infections/faq/en/

Tarnjit Khera (2014). New virus (MERS-CoV) cases increasing Scitkk.wrodpress.com



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