New Sars like Virus has longer incubation period, finds study
LONDON: In a significant finding around the virus that the World Health Organisation now calls "a threat to the entire world" scientists have found that its incubation period - the time over which it can spread among humans without showing any symptoms, is longer than presently thought.
The first detailed clinical study of the novel Sars like virus in France suggests found that the virus's incubation period in one of the patients appears to have been 9-12 days - longer than the 1-9 days previously observed.
The finding has serious implications for the duration of the quarantine required to rule out infection among contacts.
It is usually believed that a virus is most contagious when symptoms are at their worst.
However when it comes to influenza viruses, there is an incubation period once they enter the human body.
During this incubation period, while the virus keeps multiplying inside infected cells, no symptoms appear like sore throat, runny nose and aching muscles.
But what most people don't realize is that the virus keeps spreading during this time to contacts of the infected person through every drop of saliva or mucous.
A detailed clinical description of two cases of Middle East Respiratory Syndrome coronavirus (MERS-CoV) in France published in the Lancet on Thursday provides the first detailed description, outlining the symptoms the patients experienced, how they were treated, and how the virus was detected.
The first patient described, who has since died, appears to have become infected with the virus while travelling in the Middle East, and the second patient seems to have caught the virus while sharing a hospital room with the first patient (before doctors had detected the MERS-CoV infection), although the exact method of transmission is unclear.
MERS-CoV - a novel virus, similar to that which caused the SARS outbreak of 2002-03 - was first identified in two patients suffering from severe respiratory illness in September 2012. As of 23 May, 2013, there have been 44 cases worldwide.
The majority of cases have been identified in Saudi Arabia, with a smaller number of cases appearing in other countries in the Middle East (Jordan, Qatar, Tunisia, and United Arab Emirates), as well as the UK and France.
The European cases were linked to people who had been travelling in the Middle East.
For both patients, the virus could only be detected in samples taken from the lower respiratory tract - nasopharyngeal samples taken from the upper respiratory tract were negative or inconclusive for both patients.
While preliminary results in this paper suggest that the virus might be present in blood, the authors suggest that until further results are available, sputum samples from the lower respiratory tract should be taken to test for MERS-CoV infection.
Moreover, before MERS-CoV infection can be ruled out, initial negative results should be confirmed by a further sample taken a few days later
Poster Comment:
Here we go again