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More Coronavirus. This isn’t going away.

MERS-COV - EASTERN MEDITERRANEAN (19): RECEPTOR SPECIFICITY, REQUEST
FOR INFORMATION

MERS-CoV and N-linked sialic acid: a request for information

The recent observation that upper respiratory tract (URT) swabs may
not contain MERS-CoV, while the lower respiratory tract (LRT) can
harbour the virus in the same patients, suggests an hypothesis that
infection by MERS-CoV may be dependent on the variety of
neuraminidase-linked sialic acid at receptor sites in respiratory
epithelium, as is widely recognized in avian influenza [AI] virus.
Successful airborne spread of AI appears to be more likely when the
virus has adapted to attachment with alpha 2,6, N-linked sialic acid
present throughout the human URT, from where the virus can be launched
with remarkable efficiency through sneezes. (This was the case in the
1981, 1957, and 1968 AI pandemics). A/H5N1 however, is thus far
adapted to alpha 2,3, sialic acid, (which can be found in human LRT,
and especially abundant in duck enteric epithelium). This probably
accounts for the absence of pandemic spread by H5N1 through coughs and
sneezes, while allowing contagion via close (saliva/mucous) contact.
Has any study been carried out thus far on the attachment preference
(if any) of MERS-CoV with regard to N-linked sialic acid in the
respiratory tract?

—
Tim Sly, PhD, MSc, CPHI(C), DPHI
Prof, Epidemiology and Risk Studies
School of Occ. & Public Health
& School of Graduate Studies
Ryerson University
350 Victoria St. Toronto, M5B 2K3
Canada

[The location in the respiratory tract of neuraminidase-linked sialic
acid receptor sites appears to be a critical determinant of
pathogenicity in influenza virus infections. The relative absence of
MERS-CoV in swabs from the upper respiratory tract may be a reflection
of a similar situation. Can any readers provide further information in
this regard? - Mod.CP]

[see also:
MERS-CoV - Eastern Mediterranean (18): Italy, contact screening, RFI
20130603.1753321
MERS-CoV - Eastern Mediterranean (17): Saudi Arabia, Italy ex Jordan,
WHO 20130602.1751356
MERS-CoV - Eastern Mediterranean (16): Italy ex Jordan, contact cases,
WHO 20130602.1750425
MERS-CoV - Eastern Mediterranean (15): Saudi Arabia, Italy ex Jordan,
WHO, RFI 20130601.1749096
MERS-CoV - Eastern Mediterranean (14): Morocco ex UAE, RFI
20130530.1746026
MERS-CoV - Eastern Mediterranean (13): Saudi Arabia, WHO
20130530.1745063
MERS-CoV - Eastern Mediterranean (12): Saudi Arabia, France
20130528.1741836
MERS-CoV - Eastern Mediterranean (11): Saudi Arabia, new death
20130527.1738597
MERS-CoV - Eastern Mediterranean (10): animal reservoir, research
20130524.1735984
MERS-CoV - Eastern Mediterranean (09): Saudi Arabia, WHO, Jordan
20130523.1733317
MERS-CoV - Eastern Mediterranean (08): Saudi Arabia, new case, fatal,
RFI 20130522.1731245
MERS-CoV - Eastern Mediterranean (07): Tunisia ex Saudi Arabia/Qatar,
fatal, WHO 20130522.1730663
MERS-CoV - Eastern Mediterranean (06): Saudi Arabia, new fatality,
meeting 20130521.1726656
MERS-CoV - Eastern Mediterranean (05): Tunisia ex Saudi Arabia/Qatar,
fatal, RFI 20130520.1725864
MERS-CoV - Eastern Mediterranean (04): Saudi Arabia, WHO
20130520.1723626
MERS-CoV - Eastern Mediterranean (03): animal reservoir, RFI
20130519.1723544
MERS-CoV - Eastern Mediterranean (02): WHO summary, ECDC risk
assessments 20130518.1721873
MERS-CoV - Eastern Mediterranean: Saudi Arabia, new case, RFI
20130518.1721601]
.................................................cp/mj/dk
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