Indonesia - Health Minister Suspects Growing Resistance to Oseltamivir in H5N1 bird flu cases

[sharon sanders]

hat tip Diane Morin -

machine translation -

Indonesia Health Minister Suspected Bird Flu Immune Drug
Authors: Cornelius Eko SusantoFriday, January 20, 2012 22:47 pm


JAKARTA - MICOM: Health Minister Endang Rahayu Sedyaningsih suspect in Indonesia has occurred the possibility of resistance (drug resistance) to the drug oseltamivir.

The hypothesis was made based on the presence of some positive victims of bird flu in Indonesia are still died despite oseltamivir have been given early on.

"I suspect resistance to oseltamivir has been happening in Indonesia. That is why the death rate of bird flu patients here reaches more than 80% when oseltamivir was given, "said Minister of Health at a press conference after the ministerial coordination meeting to discuss bird flu on Friday (20 / 1), in Jakarta. Himself said, there may exist specific genes in the H5N1 virus in Indonesia that caused the H5N1 virus in Indonesia is more virulent than the H5N1 viruses that exist in other countries. "Honestly, I was curious as a former researcher with the possibility of the existence of this gene," he said. If there is resistance to oseltamivir, Indonesia no longer has a drug to counteract the spread of the H5N1 virus. Because, oseltamivir is the only drug that can kill the flu virus, although with certain prerequisites and conditions. In the market, oseltamivir sold under the brand Tamiflu. (Tlc/OL-5)

http://www.mediaindonesia.com/read/2012/01/20/292941/293/14/Menkes-Curiga-Flu-Burung-Indonesia-Kebal-Obat

[sharon sanders]

Re: Indonesia - Health Minister Suspects Growing Resistance to Oseltamivir in H5N1 bird flu cases

hat tip Michael Coston -

Friday, January 20, 2012

Indonesia: MOH Suspects H5N1 May Be Gaining Antiviral Resistance






# 6086


In Indonesia the antiviral Tamiflu ® (Oseltamivir) has been distributed fairly liberally over the past 6 years whenever there has been a suspected case of H5N1.

Households, whole neighborhoods - sometimes entire villages - have been placed on prophylactic antivirals in what is commonly called a `Tamiflu Blanket’.The idea is to stop or prevent household or community transmission of the virus.

And the fact that we’ve seen only a few clusters of the H5N1 virus over the years is suggestive that this policy may have been at least partially successful.

But the fear when you use antivirals is that over time, the targeted virus will develop resistance.

That happened in 2008 with the old seasonal H1N1 virus (which was supplanted by pandemic H1N1 in 2009), and in recent months we’ve seen small indications that it may be occurring in some strains of the new H1N1 virus (see NEJM: Oseltamivir Resistant H1N1 in Australia).

So far, most of the H5N1 cases we’ve seen have appeared to be sensitive to oseltamivir, although a few resistant cases have been documented in Indonesia and Egypt.

See CIDRAP’s 2007 article Tamiflu-resistant H5N1 strain surfaces in Egypt and 2005 article Tamiflu resistance in avian flu victims sparks concern.

One of the striking features about Indonesia’s H5N1 cases is the high CFR (Case fatality rate) of 82% – even with antiviral treatment – which is more than double that seen in Egypt (35%).

Today, Indonesia’s Health Minister Endang Rahayu Sedyaningsi is quoted in the media as worrying that oseltamivir may be losing effectiveness against the Indonesian strains of bird flu.

A hat tip to Diane Morin on FluTrackers for finding the following article which appears in Media Indonesia. The original link to the Indonesia (Bahasa) language version is HERE.

The following is a machine translation.

Indonesia Health Minister Suspected Bird Flu Immune Drug

Authors: Cornelius Eko Susanto
Friday, January 20, 2012 22:47 pm

JAKARTA - MICOM: Health Minister Endang Rahayu Sedyaningsih suspect in Indonesia has occurred the possibility of resistance (drug resistance) to the drug oseltamivir.

The hypothesis was made based on the presence of some positive victims of bird flu in Indonesia are still died despite oseltamivir have been given early on.

"I suspect resistance to oseltamivir has been happening in Indonesia. That is why the death rate of bird flu patients here reaches more than 80% when oseltamivir was given, "said Minister of Health at a press conference after the ministerial coordination meeting to discuss bird flu on Friday (20 / 1), in Jakarta.

Himself said, there may exist specific genes in the H5N1 virus in Indonesia that caused the H5N1 virus in Indonesia is more virulent than the H5N1 viruses that exist in other countries.

"Honestly, I was curious as a former researcher with the possibility of the existence of this gene," he said.

If there is resistance to oseltamivir, Indonesia no longer has a drug to counteract the spread of the H5N1 virus. Because, oseltamivir is the only drug that can kill the flu virus, although with certain prerequisites and conditions.

In the market, oseltamivir sold under the brand Tamiflu. (Tlc/OL-5)

Based on this article, this theory appears predicated on anecdotal observations; mostly the high CFR. What is needed now is genetic sequencing of these isolates to look for known resistance markers.

One of the big concerns over Indonesia’s prolonged refusal to share samples of the H5N1 virus was that the virus would mutate or change without the world being aware what was happening.

With new virus sharing agreements put into place last year, hopefully the world will get a good look at the viral evolution in Indonesia and be able to document if any serious changes have occurred.

Stay tuned.


Posted by Michael Coston at <a class="timestamp-link" href="http://afludiary.blogspot.com/2012/01/indonesia-moh-suspects-h5n1-may-be.html" rel="bookmark" title="permanent link"><abbr class="published" title="2012-01-20T13:10:00-05:00">1:10 PM</abbr>

[Giuseppe]

Re: Indonesia - Health Minister Suspects Growing Resistance to Oseltamivir in H5N1 bird flu cases

Because this is an old issue I invite to read this paper:

Source: US Centers for Disease Control and Prevention, Emerging Infectious Diseases Journal, full free PDF document: http://www.ncbi.nlm.nih.gov/pmc/arti...164_finalD.pdf

Reduced Sensitivity of Influenza A (H5N1) to Oseltamivir

Jennifer L. McKimm-Breschkin,* Paul W. Selleck,? Tri Bhakti Usman,? and Michael A. Johnson?


We tested the neuraminidase drug sensitivity of clade 1 and clade 2 influenza A (H5N1). All viruses demonstrated similar sensitivity to zanamivir, but compared with the 2004 clade 1 viruses, the Cambodian 2005 viruses were 6-fold less sensitive and the Indonesian clade 2 viruses were up to 30-fold less sensitive to oseltamivir. Two different strains of highly pathogenic avian influenza A (H5N1) have been circulating since 2003. Clade 1 has been found in Vietnam, Thailand, Cambodia, Lao People?s Democratic Republic, and Malaysia. Clade 2 subsequently emerged and spread from People?s Republic of China to Indonesia, Europe, and Africa in 2004?2005. Because of its systemic availability, oseltamivir is the drug of choice for treating infected persons (1).

(...)

Table 1. Mean IC50s of NA sensitivities in MUNANA*-based enzyme inhibition assay for influenza (H5N1) isolates from each region compared with a human influenza (H1N1) control and known resistant H274Y isolate?


[Isolate - Zanamivir,?? mean IC50, nmol/L - Oseltamivir,?? mean IC50, nmol/L - 4-Amino-Neu5Ac2en,?? mean IC50, μmol/L

Subtype H1N1
============
A/Mississippi/3/2001 [2]? wt 1.18 (0.24) 2.16 (0.31) 1.12?
A/Mississippi/3/2001 H274Y [4]? 1.41(0.26) 475.1 (344) 1.31?

Clade 1 subtype H5N1 2004
====================
Malaysia 2004 [2] 1.21 (0.13) 0.47 (0.07) 2.82 (0.77)
Vietnam 2004 [8] 1.40 (0.44) 0.55 (0.26) 2.47 (0.42)
Cambodia 2004 [6] 1.96 (0.56) 0.41 (0.24) 2.59 (0.15)

Clade 1 subtype H5N1 2005
====================
Cambodia 2005 [4] 1.53 (0.4) 2.88 (0.58) 2.56 (0.53)

Clade 2 subtype H5N1
================
Indonesia 2005 [6] 1.42 (0.63) 11.45 (4.32) 2.00 (0.77)


*Sigma, Saint Louis, MO, USA.
?IC50, drug concentration for 50% inhibition of enzyme activity; NA, neuraminidase; wt, wild type.
?Drugs provided by GlaxoSmithKline (Stevenage, Hertfordshire, UK).
?Nos. in brackets indicate the nos. of isolates tested against zanamivir and oseltamivir in the same assay. Nineteen influenza (H5N1) isolates were
retested in an independent assay against oseltamivir and 4-amino-Neu5Ac2en. Means for oseltamivir are the results of the 2 independent experiments.

IC50s for each isolate were calculated by using the Sigmaplot nonlinear curve-fitting function (Systat Software Inc., London, UK). Values in parentheses are standard deviations for the means of the individual IC50s for the isolates in each group.

?Several plaques were tested from the A/Mississippi/3/2001 against zanamivir and oseltamivir, but only 1 plaque of each was tested against 4-amino-Neu5Ac2en.


Table 2. Mean IC50s of isolates from each group against alternative source of oseltamivir*?

Virus Oseltamivir, IC50, nmol/L
-----------------------------
A/Mississippi/3/2001 wt 3.2 (2.1)
A/Chicken/Vietnam/008/2004 0.7 (0.4)
A/Chicken/Cambodia/Kandal/23/2004 0.4 (0.2)
A/Goose/Cambodia/Kandal/2005 4.2 (0.5)
A/Chicken/Cambodia/Kandal/3/2005 4.8 (0.5)
A/Chicken/Indonesia/Wates/77/2005 25.6 (2.5)
A/Chicken/Indonesia/Wates/126/2005 14.7 (2.3)

*IC50, drug concentration for 50% inhibition of enzyme activity; wt, wild type.
?Isolates were tested in duplicate in 2 separate assays. IC50s and standard errors (in parentheses) were calculated by using the nonlinear curve-fitting function in Sigmaplot (Systat Software Inc., London, UK).

(...)

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[Giuseppe]

Re: Indonesia - Health Minister Suspects Growing Resistance to Oseltamivir in H5N1 bird flu cases

Another paper about HA & NA genetic profiles:


A molecular and antigenic survey of H5N1 highly pathogenic avian influenza virus isolates from smallholder duck farms in Central Java, Indonesia during 2007-2008

Hendra Wibawa1,2,3*, Joerg Henning2, Frank Wong1, Paul Selleck1, Akhmad Junaidi3, John Bingham1, Peter Daniels1 and Joanne Meers2


Full PDF document: http://www.ncbi.nlm.nih.gov/pmc/arti...422X-8-425.pdf

Wibawa et al. Virology Journal 2011, 8:425

http://www.virologyj.com/content/8/1/425

Abstract

Background:
Indonesia is one of the countries most severely affected by H5N1 highly pathogenic avian influenza (HPAI) virus in terms of poultry and human health. However, there is little information on the diversity of H5N1
viruses circulating in backyard farms, where chickens and ducks often intermingle. In this study, H5N1 virus infection occurring in 96 smallholder duck farms in central Java, Indonesia from 2007-2008 was investigated and the molecular and antigenic characteristics of H5N1 viruses isolated from these farms were analysed.

Results:
All 84 characterised viruses belonged to H5N1 clade 2.1 with three virus sublineages being identified: clade 2.1.1 (1), clade 2.1.3 (80), and IDN/6/05-like viruses (3) that did not belong to any of the present clades. All three clades were found in ducks, while only clade 2.1.3 was isolated from chickens. There were no significant amino acid mutations of the hemagglutinin (HA) and neuraminidase (NA) sites of the viruses, including the receptor binding, glycosylation, antigenic and catalytic sites and NA inhibitor targets. All the viruses had polybasic amino acids at the
HA cleavage site. No evidence of major antigenic variants was detected. Based on the HA gene, identical virus variants could be found on different farms across the study sites and multiple genetic variants could be isolated from HPAI outbreaks simultaneously or at different time points from single farms. HPAI virus was isolated from both ducks and chickens; however, the proportion of surviving duck cases was considerably higher than in chickens.

Conclusions:
The 2.1.3 clade was the most common lineage found in this study. All the viruses had sequence characteristic of HPAI, but negligible variations in other recognized amino acids at the HA and NA proteins which determine virus phenotypes. Multiple genetic variants appeared to be circulating simultaneously within poultry communities. The high proportion of live duck cases compared to chickens over the study period suggests that ducks are more likely to survive infection and they may better suit the role of long-term maintenance host for H5N1. As some viruses were isolated from dead birds, there was no clear correlation between genetic variations and pathogenicity of these viruses.

(...)

The potential of NA as a target for antiviral therapy has been investigated using NA inhibitors to limit influenza virus infection by blocking the NA enzyme active site [39].

Amino acids relevant to the enzyme-active site of influenza virus neuraminidase [40] were maintained in most of the 24 isolates sequenced (Table 2).

One substitution of I223V was found in Dk/BT/387-23310/07 at the NA framework region, which has no direct contact with the substrate sialic acid.

NA sequence alignment confirmed a 20-amino acid deletion in the NA stalk region (position 49 to 68: N1 numbering), one of the proposed molecular determinants for the adaptation of influenza viruses from their wild reservoirs to domestic species [41].

Mutations at several recognised NA active sites, including E119V, R152K, D199N, H275Y and R293K, have resulted in resistance of influenza virus to NA inhibitors such as oseltamivir, zanamivir and peramivir [42,43].

Reduced sensitivity to oseltamivir has been previously reported in Indonesian H5N1 viruses isolated from poultry, which sharing I117V and I314V mutations in the NA protein [44]. However, none of the selected viruses in the present study possessed these mutations.

(...)


Conclusions

In summary, clade 2.1.3 was the dominant circulating H5N1 influenza virus in the smallholder duck farms in central Java between March 2007 and March 2008. Although all the viruses possessed HPAI molecular characteristics with multiple basic amino acids detected at the
HA cleavage site, there was no significant amino acid mutations found in either HA or NA proteins, including residues at receptor binding, glycosylation, antigenic and catalytic sites and NA inhibitor targets. Based on the HA gene, identical virus variants could be found at relatively
distant and separate geographic locations within the four study districts. Furthermore, genetically distinct variants could be isolated from either chickens or ducks on the same farm at the same time, suggesting that a range of variant viruses can circulate simultaneously within a short
period during HPAI outbreaks. Based on the antigenic analysis, there was no evidence of major antigenic variants circulating in these farms during the study period. The higher proportion of H5 virus isolations from live
ducks compared to live chickens suggests that ducks are more resistant to AI virus infection. Some of the viruses in this study were isolated from dead ducks, but there was no clear association of genetic variations with pathogenicity. Whether ducks play a role in the maintenance of Indonesian H5N1 lineage viruses is still unresolved. Therefore,
further studies are necessary to investigate other related factors determining pathogenicity in live birds as well as understanding the potential of ducks in maintaining virus infection over long periods.

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