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Brower Sept 2013
Notes: Topics covered this summer at INCDNCM 2013
Image left: This undated electron microscope image shows a novel coronavirus particle, also known as the MERS virus, center. (AP Photo/NIAID - RML)
Read more: http://www.dailystar.com.lb/News/Middle-East/2013/Sep-08/230443-another-3-die-of-mers-virus-in-saudi-arabia.ashx#ixzz2eIbKxYdj
(The Daily Star :: Lebanon News :: http://www.dailystar.com.lb
Middle East respiratory syndrome (MERS) coronavirus
In 2003 SARS-CoV outbreaks in Hong Kong were described predominantly in the two locations of 1. Amoy Gardens, where there were approximately 300 cases for which diarrhea was the primary presentation and travel through air conduits between high-rise towers was well described, and 2. Hotel Metropole, where approximately 30 cases presented primarily as respiratory disease. see: SARS: Chronology of the Epidemic. Martin Enserink Science 15 March 2013: Vol. 339 no. 6125 pp. 1266-1271 DOI: 10.1126/science.339.6125.1266
After 2004, for reasons that have remained unclear, the virus appears to have simply gone away (http://www.nytimes.com/2005/05/15/health/15sars.html?_r=0), and no similar human outbreaks have been seen until MERS was identified in 2012.
Its close resemblance to SARS-CoV was readily identified, and as with SARS, a move from an animal to human host is proposed. In the case of MERS, suspect reservoirs based on genomic studies include bats and camel. 94 cases of MERS have been described, most in Saudi Arabia, though there have been 3 cases reported from as far away as the UK; most cases have been in middle aged and older males, more often in those with some form of immune compromise, and human to human transmission appears to take place.
Serology testing is not currently reliable because of cross-reaction with other coronaviruses; PCR tests are available.
There are a number of human coronavirus receptors; of greatest interest presently in MERS is the targeted DPP4 (dipeptidyl peptidase 4) cell receptor (aka CD26), present in cells in the respiratory tract and not common to less pathogenic coronaviruses.
While the ferret, mouse, and hamster have DPP4 receptors, they cannot be infected with MERS and thus will not be viable models for in vitro studies. (MERS corona virus Does Not Replicate in Syrian Hamsters. de Wit E, Prescott J, Baseler L, Bushmaker T, Thomas T, et al. (2013). PLoS ONE 8(7): e69127. doi:10.1371/journal.pone.0069127) Studies to understand the difference between MRS and SARS are now being directed here, specifically at a domain change at the DPP4 receptor in these species. A macaque model has also been sought; macaques develop moderate numbers of pulmonary neutrophils and few macrophages after infection and recover after day 3-4.
There is some question about the tissues involved in human MERS infections; pulmonary infection is clear but reports of renal disease are less convincing and no renal pathology is seen in macaques.
Notes: Topics covered this summer at INCDNCM 2013
Image left: This undated electron microscope image shows a novel coronavirus particle, also known as the MERS virus, center. (AP Photo/NIAID - RML)
Read more: http://www.dailystar.com.lb/News/Middle-East/2013/Sep-08/230443-another-3-die-of-mers-virus-in-saudi-arabia.ashx#ixzz2eIbKxYdj
(The Daily Star :: Lebanon News :: http://www.dailystar.com.lb
Middle East respiratory syndrome (MERS) coronavirus
In 2003 SARS-CoV outbreaks in Hong Kong were described predominantly in the two locations of 1. Amoy Gardens, where there were approximately 300 cases for which diarrhea was the primary presentation and travel through air conduits between high-rise towers was well described, and 2. Hotel Metropole, where approximately 30 cases presented primarily as respiratory disease. see: SARS: Chronology of the Epidemic. Martin Enserink Science 15 March 2013: Vol. 339 no. 6125 pp. 1266-1271 DOI: 10.1126/science.339.6125.1266
After 2004, for reasons that have remained unclear, the virus appears to have simply gone away (http://www.nytimes.com/2005/05/15/health/15sars.html?_r=0), and no similar human outbreaks have been seen until MERS was identified in 2012.
Its close resemblance to SARS-CoV was readily identified, and as with SARS, a move from an animal to human host is proposed. In the case of MERS, suspect reservoirs based on genomic studies include bats and camel. 94 cases of MERS have been described, most in Saudi Arabia, though there have been 3 cases reported from as far away as the UK; most cases have been in middle aged and older males, more often in those with some form of immune compromise, and human to human transmission appears to take place.
Serology testing is not currently reliable because of cross-reaction with other coronaviruses; PCR tests are available.
There are a number of human coronavirus receptors; of greatest interest presently in MERS is the targeted DPP4 (dipeptidyl peptidase 4) cell receptor (aka CD26), present in cells in the respiratory tract and not common to less pathogenic coronaviruses.
While the ferret, mouse, and hamster have DPP4 receptors, they cannot be infected with MERS and thus will not be viable models for in vitro studies. (MERS corona virus Does Not Replicate in Syrian Hamsters. de Wit E, Prescott J, Baseler L, Bushmaker T, Thomas T, et al. (2013). PLoS ONE 8(7): e69127. doi:10.1371/journal.pone.0069127) Studies to understand the difference between MRS and SARS are now being directed here, specifically at a domain change at the DPP4 receptor in these species. A macaque model has also been sought; macaques develop moderate numbers of pulmonary neutrophils and few macrophages after infection and recover after day 3-4.
There is some question about the tissues involved in human MERS infections; pulmonary infection is clear but reports of renal disease are less convincing and no renal pathology is seen in macaques.
April 22, 2013. Editorial by Brower.
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Meetings and Resources
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For a great disease outbreak mapping resource that will highlight hotspots across the globe, go to HealthMap
For Information on Specific Infectious diseases of interest/importance see dedicated pages above.For more specific coverage of issues in Public Heath, CLICK HERE
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