H7N9: 3 New Cases & Epidemiological Follow-up On HK Imported Case

 

 

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We’ve three new H7N9 cases reported from the Chinese mainland, along with this Hong Kong’s CHP  follow-up report on yesterday’s announced imported H7N9 case (see Hong Kong Investigating 6th Imported H7N9 Case); that of an 18-month-old girl who spent much of February in neighboring Guangdong Province.

 

Thus far, 13 close contacts and 120 other contacts have been identified and are now either under quarantine or medical surveillance, but none have tested positive for the avian flu virus. 

The following report describes the epidemiological investigation being conducted on Hong Kong’s latest imported case, after which you’ll find details on the latest cases from China.

 

Epidemiological investigation and follow-up actions by CHP on confirmed human case of avian influenza A(H7N9) 

The Centre for Health Protection (CHP) of the Department of Health (DH) today (March 5) provided an update on the sixth confirmed human case of avian influenza A(H7N9) affecting an 18-month-old girl.

"The epidemiological investigations, enhanced disease surveillance, port health measures and health education against avian influenza are all ongoing," a spokesman for the DH said.

As of 4pm today, 13 close contacts and 120 other contacts have been identified.

The close contacts included relevant household members of the patient, and patients and two visitors who had stayed in the same room with the patient in Queen Elizabeth Hospital (QEH). Among them, two are symptomatic and one of them tested positive for Influenza A (H1) virus while the other tested negative for Influenza A virus. For the remaining 11 close contacts, six of them tested negative for Influenza A virus while the results for the others are pending. They are now under quarantine.

Other contacts included relevant health-care workers, visitors, immigration staff at Lo Wu, and the doctor and patients of the private clinic which the patient consulted on February 28. Among them, two are symptomatic and one of them tested negative for Influenza A virus while the result for the other is pending. They are all under medical surveillance.

"In view of human cases of avian influenza A(H7N9) confirmed locally and multiple cases notified by the Mainland, further cases are expected in affected and possibly neighbouring areas. Those planning to travel outside Hong Kong should maintain good personal, environmental and food hygiene at all times," the spokesman urged.

"All boundary control points have implemented disease prevention and control measures. Thermal imaging systems are in place for body temperature checks of inbound travellers. Random temperature checks by handheld devices have also been arranged. Suspected cases will be immediately referred to public hospitals for follow-up investigation," the spokesman added.

Regarding health education for travellers, display of posters in departure and arrival halls, in-flight public announcements, environmental health inspection and provision of regular updates to the travel industry via meetings and correspondence are proceeding.

The spokesman advised travellers, especially those returning from avian influenza-affected areas and provinces with fever or respiratory symptoms, to immediately wear masks, seek medical attention and reveal their travel history to doctors. Health-care professionals should pay special attention to patients who might have had contact with poultry, birds or their droppings in affected areas and provinces.

"We have enhanced publicity and health education to reinforce health advice on the prevention of avian influenza," the spokesman said.

(Continue. . . )

Additionally, mainland China has announced three new cases today, which are now listed on FluTrackers’ excellent H7N9 line-listing. They are:

 

FluTrackers 2013/14 Human Case List of Provincial/Ministry of Health/Government Confirmed Influenza A(H7N9) Cases with Links

 

#382 - Man, 59, onset February 25, hospitalized March 2 in critical condition in Tai'an City, Shandong province - worker from Jiangsu province

#383 - Man, 36, confirmed on 5 March morning. Before onset involved in live poultry sales. Currently in critical condition, treatment in a Xuzhou hospital. Jiangsu province

#384 - Man, 75, living in Panyu District, Guangzhou City. Due to multiple organ failure died on March 1; confirmed retrospectively on March 3. Guangdong province Death

While we have seen occasional clusters of cases suggestive of limited human-to-human transmission of this virus, thus far we’ve not seen any signs of sustained or efficient transmission in the community. 

CDC: Improving Antibiotic Prescribing Practices In Hospitals

 

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On Monday, in CDC Telebriefing (March 4th): Improving Antibiotic Prescribing Practices, I wrote about an upcoming CDC Vital Signs  report and web conference on the (often excessive) prescribing of antibiotics in US Hospitals. 

 

This morning we’ve the audio and transcript from that teleconference, excerpts and links to the MMWR early release, plus detailed reports from author and blogger Maryn McKenna and Lisa Schnirring at CIDRAP News.

 

First stop, the Teleconference contents, including links to the audio and transcript.

 

CDC Telebriefing: New Vital Signs Report - Are Prescribing Practices Putting Hospital Patients at Risk?

Poor antibiotic-prescribing practices in hospitals can needlessly put patients at risk for Clostridium difficile infection (deadly diarrhea) and future drug-resistant infections. This month, the CDC Vital Signs report looks at prescribing practices and variations, and calls on all U.S. hospitals to improve antibiotic-prescribing practices. More »

Transcript | Audio

 

Accompanying this teleconference we have the following MMWR Early Release illustrating the wide disparity in prescribing practices across the nation.

 

Vital Signs: Improving Antibiotic Use Among Hospitalized Patients

Early Release

March 4, 2014 / 63(Early Release);1-7

Scott Fridkin, MD1, James Baggs, PhD1, Ryan Fagan, MD1, Shelley Magill, MD, PhD1, Lori A. Pollack, MD1, Paul Malpiedi, MPH1, Rachel Slayton, PhD1, Karim Khader, PhD2 Michael A. Rubin, MD, PhD2, Makoto Jones, MD1, Matthew H. Samore, MD2, Ghinwa Dumyati, MD3, Elizabeth Dodds-Ashley, PharmD3, James Meek, MPH4, Kimberly Yousey-Hindes, MPH4, John Jernigan, MD1, Nadine Shehab, PharmD1, Rosa Herrera1, L. Clifford McDonald, MD1, Amy Schneider, MPH1, Arjun Srinivasan, MD1 (Author affiliations at end of text)

Background: Antibiotics are essential to effectively treat many hospitalized patients. However, when antibiotics are prescribed incorrectly, they offer little benefit to patients and potentially expose them to risks for complications, including Clostridium difficile infection (CDI) and antibiotic-resistant infections. Information is needed on the frequency of incorrect prescribing in hospitals and how improved prescribing will benefit patients.

Methods: A national administrative database (MarketScan Hospital Drug Database) and CDC's Emerging Infections Program (EIP) data were analyzed to assess the potential for improvement of inpatient antibiotic prescribing. Variability in days of therapy for selected antibiotics reported to the National Healthcare Safety Network (NHSN) antimicrobial use option was computed. The impact of reducing inpatient antibiotic exposure on incidence of CDI was modeled using data from two U.S. hospitals.

Results: In 2010, 55.7% of patients discharged from 323 hospitals received antibiotics during their hospitalization. EIP reviewed patients' records from 183 hospitals to describe inpatient antibiotic use; antibiotic prescribing potentially could be improved in 37.2% of the most common prescription scenarios reviewed. There were threefold differences in usage rates among 26 medical/surgical wards reporting to NHSN. Models estimate that the total direct and indirect effects from a 30% reduction in use of broad-spectrum antibiotics will result in a 26% reduction in CDI.

Conclusions: Antibiotic prescribing for inpatients is common, and there is ample opportunity to improve use and patient safety by reducing incorrect antibiotic prescribing.

Implications for Public Health: Hospital administrators and health-care providers can reduce potential harm and risk for antibiotic resistance by implementing formal programs to improve antibiotic prescribing in hospitals.

 

Our next stop is Maryn Mckenna’s Superbug Blog, where Maryn looks at both the issues of appropriate antibiotic stewardship, and a proposed budget increase for the HHS to monitor help control the growing problem of antibiotic resistance.

 

CDC: Some Hospitals Need Assistance Using Antibiotics Properly (And the New Federal Budget May Help)

• By Maryn McKenna
• 03.04.14 5:05 PM

Double-barreled news today from the US Centers for Disease Control and Prevention. In an analysis of several sets of hospital data, gathered by the agency and also purchased from independent databases, the CDC said it found that more than 37 percent of prescriptions written in hospitals involved some sort of error or poor practice, increasing the risk of serious infections or antibiotic resistance. And in a surprise announcement timed to the release of the federal draft budget, the agency said it is in line to receive $30 million to enhance its work combating antibiotic resistance in the US.

(Continue . . . )

 

Our last stop is CIDRAP News where Lisa Schnirring provides an excellent summation of yesterday’s reports.

 

 

CDC calls out antibiotic prescribing problems

Lisa Schnirring | Staff Writer | CIDRAP News

Mar 04, 2014

In a major report today that looked at antibiotic usage, the US Centers for Disease Control and Prevention (CDC) said some clinicians in similar hospital units prescribe triple the amounts, with some making the types of errors that fuel drug-resistance problems that put many more patients at risk.

On a more hopeful note, however, the same report also found hospitals that trim their antibiotic use by 30% can reduce Clostridium difficile (C diff) infections, a potentially deadly diarrheal infection known to sicken patients in health facilities, by 25%. The CDC published the findings today in Morbidity and Mortality Weekly Report (MMWR).

(Continue . . . )

Hong Kong Investigating 6th Imported H7N9 Case

 

 

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While the reporting of human cases from Mainland China has dwindled in recent weeks, the H7N9 virus is obviously still in circulation, and occasionally jumps to humans.  Luckily, despite roughly 380 cases reported to date, the virus has yet to demonstrate the ability to spread efficiently from human-to-human.

 

Today Hong Kong’s CHP has announced their detection of their 6th imported case, that of an 18-month old girl with recent travel history to Guangdong province.

 

4 March 2014

Imported human case of avian influenza A(H7N9) in Hong Kong under CHP investigation 

The Centre for Health Protection (CHP) of the Department of Health (DH) is today (March 4) investigating an imported human case of avian influenza A(H7N9) in Hong Kong affecting an 18-month-old girl.

 

The patient, with good past health, developed mild fever and consulted a private doctor on February 28. She attended the Accident and Emergency Department of Queen Elizabeth Hospital (QEH) for febrile convulsion on March 1. She was admitted to isolation ward for treatment after her nasopharyngeal swab tested positive for influenza upon preliminary laboratory testing by QEH on March 2. Her fever subsided completely and she was discharged in stable condition on March 3.

 

Her specimen was sent to the CHP's Public Health Laboratory Services Branch for routine detection of respiratory viruses on March 3 and tested positive for avian influenza A(H7N9) virus today.

 

According to the patient's attending clinician, the patient was initially admitted to QEH for febrile convulsion. She had no signs of pneumonia. There was no known history of suspicious exposure at the time of admission.

 

Upon confirmation as avian influenza A(H7N9) today, the patient was admitted to Princess Margaret Hospital (PMH) for isolation and testing. She is now asymptomatic with no fever.

 

Initial epidemiological investigations by the CHP revealed that the patient, who lives in To Kwa Wan, had travelled to Shunde, Foshan, Guangdong, from February 5 to 27 during which she was brought to a nearby wet market by her mother on February 24 but they did not buy any poultry. She had stayed in local residence with no known poultry nearby.

 

"Further investigations into her travel and exposure histories are ongoing in parallel with contact tracing. Close contacts including relevant household members and patients who had stayed in the same room with the patient in QEH will be admitted for testing and observation, while other contacts including relevant healthcare workers, visitors, immigration staff at Lo Wu, the doctor and patients of the private clinic which the patient consulted on February 28, will all be put under medical surveillance," a spokesman for the CHP explained.

 

The CHP will liaise with relevant Mainland health authority to follow up the patient's contacts during her stay in the Mainland.

 

"The Serious Response Level under the Government's Preparedness Plan for Influenza Pandemic remains activated and the CHP's follow-up actions are in full swing," the spokesman said.

 

This is the sixth confirmed human case of avian influenza A(H7N9) in Hong Kong. The CHP will notify the World Health Organization (WHO), the National Health and Family Planning Commission as well as health and quarantine authorities of Guangdong and Macao.

 

Locally, enhanced surveillance of suspected cases in public and private hospitals is underway. The CHP will continue to maintain liaison with the WHO, the Mainland and overseas health authorities to monitor the latest developments. Local surveillance activities will be modified upon the WHO's recommendations.

 

"In view of human cases of avian influenza A(H7N9) confirmed locally and multiple cases notified by the Mainland, further cases are expected in affected and possibly neighbouring areas. Those planning to travel outside Hong Kong should maintain good personal, environmental and food hygiene at all times," the spokesman urged.

 

"All boundary control points have implemented disease prevention and control measures. Thermal imaging systems are in place for body temperature checks of inbound travellers. Random temperature checks by handheld devices have also been arranged. Suspected cases will be immediately referred to public hospitals for follow-up investigation," the spokesman added.

(Continue . . .)

Ends/Tuesday, March 4, 2014

mBio: Characterizing A Novel Influenza C Virus In Bovines & Swine

Photo Credit Wikipedia

 

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In virology, perhaps as much as any field of scientific endeavor, the half-life of `facts’  continues to decline.  Fresh discoveries, propelled by new technologies and concerns over the threats posed by emerging viruses, have conspired to obsolete many textbooks (and blog articles) almost as soon as they are published.

 

Case in point:  A year ago, little thought was given to influenza C viruses. 

 

A visit to the CDC’s Flu Basics `Types Of Influenza Viruses’ page barely finds mention of  influenza C.

 

There are three types of influenza viruses: A, B and C. Human influenza A and B viruses cause seasonal epidemics of disease almost every winter in the United States. The emergence of a new and very different influenza virus to infect people can cause an influenza pandemic. Influenza type C infections cause a mild respiratory illness and are not thought to cause epidemics.

 

Since most of us are exposed as children, influenza C is regarded as posing a minimal health threat. This lack of respect for influenza C is due mainly to its lack of genetic diversity and slow rate of evolution. 

 

Essentially, it was believed if you’d seen one subtype of Influenza C, you’ve pretty much seen them all. 

 

But last year, a group of researchers published (PLoS Pathogens) their finding and Isolation of a Novel Swine Influenza Virus from Oklahoma in 2011 Which Is Distantly Related to Human Influenza C Viruses, which threatened to rewrite the textbooks on Influenza C.  The authors wrote:

Based on its genetic organizational similarities to influenza C viruses this virus has been provisionally designated C/Oklahoma/1334/2011 (C/OK). Phylogenetic analysis of the predicted viral proteins found that the divergence between C/OK and human influenza C viruses was similar to that observed between influenza A and B viruses. No cross reactivity was observed between C/OK and human influenza C viruses using hemagglutination inhibition (HI) assays.

Additionally, the authors found that this new (provisional) influenza C virus could infect, and transmit, in both ferrets and pigs.  The authors described this new discovery as:

 

. . .  a new subtype of influenza C viruses that currently circulates in pigs that has not been recognized previously. The presence of multiple subtypes of co-circulating influenza C viruses raises the possibility of reassortment and antigenic shift as mechanisms of influenza C virus evolution.

 

Fast forward a year, and these same researchers are back, this time in the open access journal mBio, with an update on this new influenza C subtype, which they now have found circulates in both cattle and swine.

 

Characterization of a Novel Influenza Virus in Cattle and Swine: Proposal for a New Genus in the Orthomyxoviridae Family

Ben M. Hause^a, Emily A. Collin^a,b, Runxia Liu^b,c, Bing Huang^b,c,d, Zizhang Sheng^e, Wuxun Lu^b,c, Dan Wang^b,c, Eric A. Nelson^b,c, Feng Li^b,c

ABSTRACT

We have recently reported the isolation of a novel virus, provisionally designated C/swine/Oklahoma/1334/2011 (C/OK), with 50% overall homology to human influenza C viruses (ICV), from a pig in Oklahoma. Deep RNA sequencing of C/OK virus found a matrix 1 (M1) protein expression strategy that differed from that of ICV. The novelty of C/OK virus prompted us to investigate whether C/OK virus could exist in a nonswine species.

Significantly, we found that C/OK virus was widespread in U.S. bovine herds, as demonstrated by reverse transcription (RT)-PCR and serological assays. Genome sequencing of three bovine viruses isolated from two herds in different states further confirmed these findings. To determine whether swine/bovine C/OK viruses can undergo reassortment with human ICV, and to clarify the taxonomic status of C/OK, in vitro reassortment and serological typing by agar gel immunodiffusion (AGID) were conducted. In vitro reassortment using two human ICV and two swine and bovine C/OK viruses demonstrated that human ICV and C/OK viruses were unable to reassort and produce viable progeny. Antigenically, no cross-recognition of detergent split virions was observed in AGID between human and nonhuman viruses by using polyclonal antibodies that were reactive to cognate antigens.

Taken together, these results demonstrate that C/OK virus is genetically and antigenically distinct from ICV. The classification of the new virus in a separate genus of the Orthomyxoviridae family is proposed. The finding of C/OK virus in swine and bovine indicates that this new virus may spread and establish infection in other mammals, including humans.

IMPORTANCE Influenza C viruses (ICV) are common human pathogens, infecting most people during childhood and adolescence, and typically cause mild respiratory symptoms. While ICV have been isolated from both pigs and dogs, humans are thought to be the natural viral reservoir. Previously, we characterized an ICV-like virus isolated from pigs exhibiting symptoms of influenza virus-like illness. Here, we show molecular and serological data demonstrating widespread circulation of similar viruses in bovines.

Deep RNA sequencing, phylogenetic analysis, and in vitro reassortment experiments demonstrate that animal ICV-like viruses are genetically distinct from human ICV. Antigenically, we show that ICV-like viruses are not recognized by ICV antibodies. En masse, these results suggest that bovine influenza virus warrants classification as a new genus of influenza virus. The finding of this novel virus that can infect multiple mammalian species warrants further research into its role in human health.

(Continue . .  )

 

Although first isolated in swine, seroprevalence studies only showed about 10% of pigs sampled had antibodies to this influenza C virus, prompting researchers to look for another host species. Subsequent testing of cattle across multiple states found high antibody titers to C/OK viruses, suggesting they are the likely primary reservoir host for this subtype.

 

It seems that hardly a month goes by when we don’t learn of a new virus or pathogen, such as we saw last year in PLoS Pathogens: New World Bats Harbor Diverse Flu Strains.  Until 2012, bats were never thought of as a host for influenza viruses, but now we know different.

 

Last September, in mBio: A Strategy To Estimate The Number Of Undiscovered Viruses, we looked at an attempt by researchers at Columbia University's Mailman School of Public Health, EcoHealth Alliance, the NIH, and universities and research centers around the world to estimate the number of viruses in the wild, awaiting discovery.

 

The good news is, the estimated number of viruses out there is finite, the bad news is, we are probably talking 6 figures.

 

As far at the potential human health impact from this recently discovered C/OK virus is concerned, the jury is still out.  The authors write:

 

It is unknown if C/OK virus has an impact on human health. The ability to infect and transmit in ferrets, a model for human influenza virus pathogenesis studies, suggests this pathogen has the potential to cause disease in humans. Limited serology on a subset of human serum samples showing a 1.3% positive rate also supports this hypothesis. The prevalence of C/OK virus in cattle and presumptive spillover to swine, both of which live in close proximity to humans, further highlights its potential threats to human health, which merit further studies.

 

 

Regardless of the future impact of this particular discovery, one thing is certain.  We are unlikely to run out of new things to talk about in virology anytime in our lifetimes.

 

It is truly a vast, and largely undiscovered, scientific frontier.

ECDC: 2013-14 Seasonal Influenza Risk Assessment

ECDC Weekly Infographic On Influenza

 

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Each year, usually in late February, the ECDC releases an updated Risk Assessment on their current influenza season, comparing it to previous years, and to reports coming from other regions around the world. 

 

Compared to North America, Europe’s flu season got off to a later start and hasn’t been anywhere near as A(H1)pdm09-dominated (or as severe) as what we’ve experienced on this side of the pond this year. 

From the Report:

In contrast to the season in the US with an overwhelming dominance of A(H1)pdm09 virus and substantial numbers of severe cases, A(H1)pdm09 virus is not as dominant in EU/EEA countries, possibly due to differences in prior exposure to A(H1)pdm09 virus or higher vaccination coverage among the age groups most likely to transmit the disease. In countries not yet affected, the pressure on primary and secondary care services is likely to be less intense than in the US.  

 

This year’s report (13-page PDF file) was posted today on the ECDC website. You’ll find their summary below, along with links to the report.

 

 

Seasonal influenza in Europe: ECDC risk assessment for the 2013-2014 season

04 Mar 2014

​Active circulation of influenza has started late in Europe in the 2013-2014 season, with a different timing across EU/EEA countries, states the annual ECDC risk assessment on seasonal influenza. The first countries affected have been Bulgaria, Greece, Portugal and Spain, where the A(H1)pdm09 influenza virus has dominated. Without any specific geographic pattern, influenza activity has since spread rapidly across Europe. In Bulgaria, Portugal and Spain, the season peaked in weeks 4 and 5/2014, while influenza activity still continues to increase in Greece.

Circulating virus types

In week 07/2014, circulating A(H1)pdm09 virus was dominant or co-dominant in 21 reporting countries while A(H3) was dominant in four countries. In contrast to the season in the US with an overwhelming dominance of A(H1)pdm09 virus and substantial numbers of severe cases, A(H1)pdm09 virus is not as dominant in EU/EEA countries. This may be due to differences in prior exposure to A(H1)pdm09 virus or higher vaccination coverage among the age groups most likely to transmit the disease.

Vaccine effectiveness

Data on viruses circulating so far indicate a good match with the current influenza vaccine. North American studies estimate high to moderate vaccine effectiveness, while a mid-season study from one Spanish region, Navarre, suggests lower effectiveness. This warrants further studies to understand the discrepancies. Vaccination of high-risk groups and healthcare workers, in accordance with national guidelines, in countries that are still at an early stage in their influenza season remains the most effective way of reducing serious outcomes and transmission of the disease.

 

Risk assessment for the remaining season

• In countries with A(H1)pdm09 circulating, especially in countries where influenza activity has already peaked, a later circulation of A(H3) virus is possible. In the event of A(H3) virus circulation, some severe cases are likely, most probably in people older than those typically infected by A(H1)pdm09 virus.
• In countries currently with no/low influenza activity, the dominant influenza virus strain and the intensity are unpredictable, but are likely to be similar to that observed in countries that have already passed their intensity peak (Bulgaria, Portugal and Spain). However, differences in vaccination coverage and natural immunity may influence both intensity and the number of severe cases.
• In the few countries where A(H3) virus has been dominant so far, a second wave or a co-circulation of A(H1)pdm09 virus is possible.

Read full report: Seasonal influenza 2013-2014 in EU/EEA countries

More on seasonal influenza

Weekly infographic on Influenza in Europe 

EID Journal: H5N1 Clade 2.3.2.1 In Indonesia

Diversity of circulating H5N1 Clades – Credit WHO

 

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While we tend to talk about H5N1 (aka `bird flu’) as if it were a single entity, in reality, the virus has continually evolved and mutated since its emergence was first noted in 1996. At least 20 distinct clades of the virus have been identified thus far,  with numerous variants among each clade.

 

`Clades’ are essentially branches on the virus’s family tree. Each new branch has a clearly identifiable lineage from its parental strain, but has mutated far enough away to become a new strain.  And different clades can possess different characteristics .

 

Different areas of the world have seen different clades set up hen-house keeping, with clade 2.3.2  very common in South East Asia, clades 2.2.1 and 2.2 endemic in Egypt and clades 2.1.1, 2.1.2. and 2.1.3 circulating throughout Indonesia.

 

While not every new clade has what it takes to thrive and persist, one of the more successful `newer’ clades making inroads over the past few years has been clade 2.3.2. 

 

I wrote of the spread of this emerging clade back in 2011 in What Goes Around, Comes Around and EID Journal: H5N1 Branching Out. In the spring of 2010 we began to see reports of poultry vaccine failures in Vietnam due to the spread of a mutated version this clade (further classified as clade 2.3.2.1), which led to this statement FAO Warns On Bird Flu.

 

In December of 2012, after several months of reports of large poultry die offs in Indonesia, we first heard that his emerging 2.3.2.1 clade had been detected on the Island of Java (see VOA Report On The Indonesian Duck Die Off & Report: Clade 2.3.2 H5N1 Detected In Indonesia).  A month later, we saw reports that Indonesia: H5N1 Clade 2.3.2 Reaches Bali.

 

While we’ve heard relatively little out of Indonesia on the bird flu front over the past year, today we have a detailed look at this new H5N1 clade that arrive in Java in 2012, via a dispatch in the CDC’s EID Journal.

Genetic Characterization of Clade 2.3.2.1 Avian Influenza A(H5N1) Viruses, Indonesia, 2012

Ni Luh Putu Indi Dharmayanti , Risza Hartawan, Hendra Wibawa, Amanda Balish, Ruben Donis, C. Todd Davis, Gina Samaan, and Pudjiatmoko Hardiman

Abstract

After reports of unusually high mortality rates among ducks on farms in Java Island, Indonesia, in September 2012, influenza A(H5N1) viruses were detected and characterized. Sequence analyses revealed all genes clustered with contemporary clade 2.3.2.1 viruses, rather than enzootic clade 2.1.3 viruses, indicating the introduction of an exotic H5N1 clade into Indonesia.

<SNIP>

Conclusions

Detection of a novel clade of A(H5N1) virus in Indonesia marks a potential turning point in the molecular epidemiology of this virus. Indonesia has the highest number of human A(H5N1) infections because of ongoing outbreaks in poultry (14,15).

Whether this new virus will become entrenched, as did clade 2.1.3 viruses over the past decade, remains to be seen, as do its effects on the incidence of human infection. Potential cocirculation of subtypes of 2 different clades warrants review of diagnostic methods and vaccination strategy to maximize effectiveness of disease control interventions.

The lack of antigenic relatedness between the clade 2.3.2.1 and 2.1.3.2 viruses must be considered when evaluating A(H5N1) serologic diagnostic reagents used in Indonesia. This change also may have implications in selecting prepandemic candidate vaccine virus for the region. Furthermore, poultry vaccines may need to be matched antigenically to circulating virus if clade 2.3.2.1 virus continues to circulate in Indonesia.

Introduction of this virus is a stark reminder of the value of control measures to reduce the spread of subtype H5N1 and the need for enhanced surveillance of humans and poultry to monitor changes in its genetic and immunologic features.

 

 

Last November, in EID Journal: The Expanding Variants Of H5N1 we looked at three new variations of the H5N1 virus (this time clade 2.3.4) detected in Vietnam between 2009 and 2012.  And last month, in Moving Viral Targets, we saw a recommendation – based on a virus isolated in Hubei - that a new clade 7.2 candidate vaccine virus be developed.

 

And there is no reason to believe we won’t see new genetic permutations like these continue to come down the pike in the months and years to come.

 

A reminder that influenza viruses (of all types) are moving targets, and that we dare not become complacent simply because the novel viruses in circulation right now aren’t particularly good at transmitting from one human to the next.

For more influenza clades and variants than we can possibly keep track of, tomorrow is always another day.