Australia reports first Tamiflu-resistant H1N1 case

[Gert van der Hoek]

Australia reports first Tamiflu-resistant H1N1 case

11 Sep 2009 08:15:34 GMT

Source: Reuters

SYDNEY, Sept 11 (Reuters) - The first Australian case of swine flu resistant to Roche Holding AG's <ROG.VX> antiviral drug Tamiflu was confirmed by the Western Australia state government on Friday.

"The 38-year-old Perth man, who has a weakened immune system, initially responded to the drug but developed a resistant strain of the virus when his illness relapsed," the state's Department of Health said in a statement.

There have been 13 cases of Tamiflu-resistant infections around the world, the statement said.

A Roche executive said on Monday that isolated cases of Tamiflu-resistant H1N1 pandemic flu were to be expected, in line with what has been seen in clinical studies. [ID:nL7314194]

"There is no evidence that the virus has spread to other people. None of the patient's family or hospital staff caring for him have contracted the virus, and he has not been in contact with the wider community," said the state's Chief Health Officer Tarun Weeramanthri, adding that the case was a rare and isolated one.

The man remained in a critical condition in intensive care.

http://www.alertnet.org/thenews/newsdesk/SYD444789.htm

Comment: at least 22 cases of Tamiflu resistant H1N1 samples are reported untill now.

[alert]

Re: Australia reports first Tamiflu-resistant H1N1 case

I believe today's ProMED post is referring to this case. Note that the case recovered, but then died during an unrelated (?) operation.

http://www.promedmail.org/pls/otn/f?p=2400:1001:1856480509705873::NO::F2400_P1001_BACK_PAGE,F2400_P1001_PUB_MAIL_ID:1000,80874

Archive Number 20100111.0127
Published Date 11-JAN-2010
Subject PRO/AH/EDR> Influenza pandemic (H1N1) (04): Australia (WA), i/v zanamivir


INFLUENZA PANDEMIC (H1N1) (04): AUSTRALIA (WESTERN AUSTRALIA),
INTRAVENOUS ZANAMIVIR
***********************************************
A ProMED-mail post
<http://www.promedmail.org>
ProMED-mail is a program of the
International Society for Infectious Diseases
<http://www.isid.org>

Date: Mon 11 Jan 2010
Source: 6minutes.com, Australia [edited]
<http://www.6minutes.com.au/articles/z1/view.asp?id3D508962>


A kidney transplant patient in WA [Western Australia] has died after
developing Australia's 1st case of pandemic (H1N1) 2009 influenza
resistant to oseltamivir (Tamiflu). However, the virus still appears
to be sensitive to zanamivir (Relenza) says Dr David Speers,
Infectious Diseases Physician at the Sir Charles Gairdner Hospital in
Perth, in a case report in the MJA [the Medical Journal of Australia]
today, 11 Jan 2010;
<http://www.mja.com.au/public/issues/192_03_010210/spe11148_fm.html>].

Dr Speers and colleagues say their patient initially became infected
with wild-type [i.e. oseltamivir-sensitive] (H1N1) 2009 influenza
virus after undergoing a renal transplant and while taking
immunosuppressant drugs. After a 10-day course of oral oseltamivir,
the patient developed rapid-onset severe primary viral pneumonia due
to oseltamivir-resistant virus, and respiratory failure progressed
despite high-dose oral oseltamvir and nebulised zanamivir. The patient
improved and became negative for influenza after being treated with
intravenous zanamivir but subsequently died from intraperitoneal sepsis.

The report's authors say the resistant virus contained the H275Y NA
[neuraminidase] mutation, which is the major [so far only known]
mechanism for oseltamivir resistance in influenza virus infection.
Until now, most of the 31 cases of resistance reported worldwide have
occurred in people taking oseltamivir as post-exposure prophylaxis,
they note.

They say the patient developed the resistant [virus] a few days after
stopping his initial course of oseltamivir, "possibly due to declining
blood and tissue levels of the antiviral drug." They conclude by
saying that intravenous zanamivir may prove to be a useful antiviral
therapy for severely unwell influenza patients, including those with
oseltamivir-resistant pandemic (H1N1) 2009 infection.

[Byline: Michael Woodhead]

--
Communicated by:
ProMED-mail Rapporteur Mary Marshall

[This 1st oseltamivir-resistant pandemic (H1N1) 2009 virus in
Australia was isolated during the course of treatment of an
immunosuppressed renal transplant patient with high doses of the
antiviral drug. The patient developed severe respiratory disease
thought to be the consequence of selection of drug resistant virus as
a result of treatment with high doses of oseltamivir.

Subsequently, the resistant virus infection was cleared by intravenous
administration of the alternate influenza virus neuraminidase
inhibitor zanamivir, and the patient recovered, although,
unfortunately, he did not ultimately survive the organ
transplantation. Nonetheless, it is concluded that intraveous
administration of zanamivir may be a useful mode of antiviral therapy
in cases of oseltamivir resistance.

A map of Western Australia showing the location of Perth can be
accessed at:
<http://www.weltlaeufig.de/wp-content/uploads/2008/09/map-of-western-australia.jpg>. The HealthMap/ProMED-mail interactive map of Australia is available at: <http://healthmap.org/r/00cS>. -
Mod.CP]

[see also:
2009
----
Influenza pandemic (H1N1) 2009 (78): USA oseltamivir resist. 20091030.3753
Influenza pandemic (H1N1) 2009 (77): Taiwan oseltamivir resistance
20091027.3725
Influenza pandemic (H1N1) 2009 (74): Canada (ON) oseltamivir resist
20091022.3634
Influenza pandemic (H1N1) 2009 (73): Taiwan oseltamivir resist 20091021.3626
Influenza pandemic (H1N1) 2009 (50): oseltamivir resistance 20090917.3260]
.................................................. .........cp/msp/jw