LOC21:50
18:50 GMT
influenza
GENEVA, Dec 2 (KUNA) -- The World Health Organization (WHO) said Wednesday
that it has been informed of two recent clusters of patients infected with
oseltamivir-resistant H1N1 viruses detected in Wales, UK and North Carolina,
US.
Those resistant cases occurred in a single ward in a hospital, and both
involved patients whose immune systems were severely compromised or suppressed.
Transmission of resistant virus from one patient to another is suspected in
both outbreaks.
The emergence of drug-resistant influenza viruses in severely
immunosuppressed or immunocompromised patients undergoing antiviral treatment
is not unexpected and has been well documented during seasonal influenza.
Virus replication can persist in such patients for prolonged periods of
time despite antiviral treatment, creating an environment in which
drug-resistant viruses can readily be selected.
This phenomenon has also been observed for the pandemic (H1N1) 2009.
Upon receipt of the reports, WHO organized a telephone conference with
officials and staff from the hospitals and experts in clinical medicine,
epidemiology, and virology to discuss the two outbreaks.
Particular attention is being given to the best treatment options for
immunocompromised patients who become infected with the pandemic virus.
The Wales outbreak, which was detected in late October, involved eight
patients. All of these patients were hospitalized because of severe
haematological disorders. No deaths occurred. Three of these patients remain
in hospital, with one being treated in intensive care.
In the US outbreak, which involved four severely immunocompromised
patients, cases occurred in a two-week period between mid-October and early
November. Three of the four cases were fatal, but the role of H1N1 infection
in contributing to these deaths is uncertain.
All of the resistant viruses carried the same H275Y mutation, indicating
resistance to oseltamivir but susceptibility to the second antiviral drug,
zanamivir. (end)
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