Tsunami Preparedness Week 2019

Credit NOAA Tsunami Safety PDF

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While most people think the Tsunami threat is primarily limited to the Pacific and Indian Ocean, as we've discussed previously (see The Caribbean’s Hidden Tsunami Potential (Revisited), the Caribbean and the Atlantic both have a history of seismic activity.

In 1995, Montserrat's previously dormant Soufrière Hills volcano sprang to life, destroying the capital city of Plymouth, and rendering half the island uninhabitable.

In 2013 the  USGS warned the Earthquake/Tsunami Hazard in Caribbean Higher Than Previously Thought, stating `Enough strain may be currently stored in an earthquake zone near the island of Guadeloupe to cause a magnitude 8 or larger earthquake and subsequent tsunami in the Caribbean’

While rare, the Atlantic seaboard, Florida, and even the Gulf of Mexico are not immune to Tsunamis (see East Coast Tsunami Threats). A list of known or suspected Atlantic Tsunamis includes:

• November 1, 1755 - Lisbon, Portugal
• October 11, 1918 - Puerto Rico
• November 18, 1929 - Newfoundland
• August 4, 1946 - Dominican Republic
• August 18, 1946 - Dominican Republic
• November 14, 1840 - Great Swell on the Delaware River
• November 17, 1872 - Maine
• January 9, 1926 - Maine
• May 19, 1964 - Northeast USA

In 1992, a `rogue wave'  - described by witnesses as being between 10 and 18 feet tall - slammed onto a 27 mile stretch of Florida Beaches (including Daytona Beach) and smashed hundreds of cars and caused as many as 75 (mostly minor) injuries.

Even though destructive tsunamis are rare - if you live in, work at, or visit any coastal region - you should be aware of the potential threat, and what to do if a tsunami warning is issued.

The two biggest tsunamis in recent history are the 2004 Indian Ocean Tsunami, which killed upwards to 250,000 people, and Japan's 2011 Tōhoku Earthquake/Tsunami which killed in excess of 15,000 people.

While less deadly, Alaska's 1964 earthquake produced significant tsunami effects both locally, and thousands of miles away, killing 5 in Oregon and 13 in California. Chile's 1960 Valdivia earthquake sent a train of tsunamis across the Pacific, causing heavy damage and loss of life in Hawaii, Japan, and beyond (see NOAA Report).

A reminder that large earthquakes, volcanic eruptions, or tsunamis that occur even thousands of miles away still have the potential to impact people around the globe.

The National Tsunami Hazard Mitigation Program (NTHMP) recognizes  Tsunami Preparedness Week during the last week in March to coincide with the date of the 1964 Great Alaska Earthquake and Tsunamis, although observances vary by state or territory. Below is aan updated list for 2019:

• March 10-16: Puerto Rico, U.S. Virgin Islands
• March 24-30: Alaska
• National Tsunami Warning Center Open House: Saturday, March 30, 1-4pm
• March 25-29: California
• April: Hawaii
• April 8-12: Washington (Road Show)

In 2013 the USGS released a report detailing the likely West Coast impact of a tsunami generated by a 9.1 Alaskan earthquake – and the numbers are sobering.  From the USGS news release  Experts Team Up on Tsunami Resilience in California:

In this scenario approximately 750,000 people would need to be evacuated, with 90,000 of those being tourists and visitors. Additionally, one-third of the boats in California's marinas could be damaged or completely sunk, resulting in $700 million in losses. It was concluded that neither of California's nuclear power plants would likely be damaged by this particular event.

The study (link) also estimates damage to marinas, businesses and homes range between $3.5 billion and $6 billion, and as many as 8,500 could be left homeless.

 
An even greater threat lurks along the Cascadia Fault line, which runs parallel to the Pacific Northwest Coastline and has a long history of a producing major earthquakes and tsunamis, the last one in the year 1700. The geological record indicates massive quakes have struck the region at least 7 times over the past 3500 years.

Publicity in the New Yorker Magazine a couple of years ago has raised awareness of this threat and we’ve seen renewed calls for preparedness in the region (see OSU: Pragmatic Action - Not Fatalism - In Order To Survive The `Big One’).   We also ooked at the threats posed by this particular fault line back in 2011 in Just A Matter Of Time. 

While strong earthquakes are the most common cause of tsunami waves, other causes include submarine landslides, meteo-tsunamis generated by anomalous weather events, and rarest of all – tsunamis caused by asteroid impacts.

As far as what to do before a tsunami threatens, READY.GOV has a Tsunami Awareness Page with helpful hints.

Between hurricanes, tornadoes, wildfires, earthquakes, blizzards, floods, wildfires, and tsunamis - there really isn't anywhere you can live that isn't susceptible to some type of natural disaster.  

Which is why everyone - regardless of where they live - needs to have an appropriate disaster plan, just as everyone should have a good first aid kit, a `bug-out bag’, and sufficient emergency supplies to last a bare minimum of 72 hours.

While 72 hours is an admirable start, I wouldn't feel terribly comfortable with it. Here in the United States many agencies and organizations recommend that households work towards having a 10-to-14 day supply of food, water, and emergency supplies on hand.  
 
If you aren't already well prepared, I would invite you to visit Ready.gov, FEMA, or revisit these blogs:

In An Emergency, Who Has Your Back?

An Appropriate Level Of Preparedness

When 72 Hours Isn’t Enough.

China MOA: 1st Outbreak Of H7N9 (in Birds) Since Summer of 2018

Liaoning Province - Credit Wikipedia

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During the summer of 2017, at the tail end of the biggest H7N9 outbreak (in humans) on record, China ordered the emergency nationwide deployment of a new, experimental H5+H7 poultry vaccine.

Unlike previous campaigns, which had produced limited and mixed results, China's dramatic drop in human infections, outbreaks in poultry, and virus detection from routine surveillance since then has been nothing short of remarkable.

While we've seen some breakthroughs of H5N6 - including 5 human infections last year - the last mention of an H7N9 outbreak in poultry I can find comes from the FAO in the summer of 2018 while the last human infection was reported more than a year ago (February 2018).

Despite this welcomed respite, we've seen enough cracks in this viral veneer to believe the H7 and H5 threat in China is far from over. 

Viruses mutate, and over time vaccines against them lose their effectiveness.  Add in the reintroduction of viruses from outside of China's vaccination zone, and the inevitable reassortments that occur, and this quiescence was unlikely to persist.

Today, China's MOA reports the first outbreak of H7N9 in eight months, involving peacocks at the Jinzhou City Zoo. Of note, the virus tested as HPAI which emerged in late 2016, not the more common LPAI strain.

H7N9 highly pathogenic avian influenza epidemic occurred in Linghe District, Jinzhou City, Liaoning Province

Date: 2019-03-25 17:50 Author: Source: Ministry of Agriculture and Rural Press Office 

The Information Office of the Ministry of Agriculture and Rural Affairs announced on March 25 that a peacock H7N9 subtype highly pathogenic avian influenza epidemic occurred in Linghe District, Jinzhou City, Liaoning Province.

On March 25, the Ministry of Agriculture and Rural Affairs received a report from the China Animal Disease Prevention and Control Center and was diagnosed by the National Avian Influenza Reference Laboratory. 

The ornamental peacocks raised in the zoo of Jinzhou City, Liaoning Province, developed H7N9 subtype highly pathogenic avian influenza. The park's memory bar watched 394 birds of poultry, with 9 diseases and 9 deaths. 

After the outbreak, the local authorities in accordance with the relevant plans and technical requirements for prevention and control, do a good job in the treatment of the epidemic situation, have culled 191 birds, all dead and culled birds have been harmless treatment.

Despite the breakthrough events with H5N6, a single human H7N4 infection reported a year ago from Jiangsu, some scattered H9N2 infections, and today's H7N9 report, avian flu remains greatly suppressed in China.

How long that happy state of affairs lasts, however, is anyone's guess.

Eurosurveillance: H3N2 Virus With Reduced Susceptibility to Baloxavir - Japan, Feb 2019

Credit NIAID

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Like the cliffhanger serials of old, scientific findings and discoveries tend to present themselves in tantalizing chunks of incomplete data, which often leads us to the next clue, a fork in the road, or sometimes a dead end.

Scientific discovery is a process, which can often be messy, and progress is rarely linear (see When Studies Collide (Revisited))

But most importantly, our current understanding of nearly any scientific topic is simply that, and is almost certain to change. Which is why this blog spends so much time attempting to put new studies into context, presenting past works, and trying to make connections between them.

All of which serves as a caveat of sorts to the following Rapid Communications, published in this week's Eurosurveillance, on discoveries made only a few weeks ago regarding the new influenza anti-viral Baloxavir, that have already been partially overshadowed by even more recent events.  

Baloxavir marboxil (trade name Xofluza®) was approved in the United States last October (see FDA Approval Of Xofluza : A New Class Of Influenza Antiviral, but has been in use in Japan for about a year, and roughly 5.5 million doses have been administered there. 

In recent months we've seen some subtle signs of resistance cropping up in Japan among patients already being treated with the new antiviral (see CIDRAP's Experts on watch for resistance to new flu drug).

The development of `spontaneous resistance' in a patient receiving an antiviral is a known - but relatively rare - occurrence.  And the mutated virus is generally believed to take a `fitness' hit, making it unlikely (but not impossible) to be transmitted efficiently to others.

After several cases of `spontaneous resistance' developing in Baloxavir-treated children infected with H3N2 were reported last December (see January Eurosurveillance report), Japan began an enhanced national surveillance campaign.

This week's Eurosurveillance report describes two children in Japan, ages 6 & 7, who were found to have a mutated `resistant' H3N2 virus; one of whom received Baloxavir, and the other (with no epidemiological link to the first) who received oseltamivir (Tamiflu). 

But as anyone who has already read my blog of 10 days ago  (see Japan NIID Reports 3 Xofluza Resistant Flu Viruses In Untreated Patients) already knows, the story continues to unfold. 

First some excerpts from the latest Eurosurveillance report, and then I'll return with a bit more.

Rapid communication Open Access

Influenza A(H3N2) virus exhibiting reduced susceptibility to baloxavir due to a polymerase acidic subunit I38T substitution detected from a hospitalised child without prior baloxavir treatment, Japan, January 2019

Emi Takashita1, Chiharu Kawakami2, Rie Ogawa1, Hiroko Morita1, Seiichiro Fujisaki1, Masayuki Shirakura1, Hideka Miura1, Kazuya Nakamura1, Noriko Kishida1, Tomoko Kuwahara1, Akira Ota3, Hayato Togashi3, Ayako Saito4, Keiko Mitamura5, Takashi Abe6, Masataka Ichikawa7, Masahiko Yamazaki8, Shinji Watanabe1, Takato Odagiri1

The cap-dependent endonuclease inhibitor baloxavir marboxil became available in Japan in March 2018 for the treatment of influenza virus infection in patients aged 12 years and older and children younger than 12 years weighing at least 10 kg. Between October 2018 and January 2019, baloxavir was supplied to medical institutions that together serve ca 5.5 million people. 

In December 2018, we detected influenza A(H3N2) viruses exhibiting reduced susceptibility to baloxavir from baloxavir-treated children aged 6 and 7 years [1]. These viruses possessed an I38T substitution in the polymerase acidic subunit (PA), which confers reduced susceptibility to baloxavir [2]. We subsequently increased nationwide monitoring of the baloxavir susceptibility of circulating influenza viruses, irrespective of antiviral treatment [3]. 

In January 2019, we isolated two influenza A(H3N2) viruses, A/YOKOHAMA/87/2019 and A/YOKOHAMA/88/2019, from two hospitalised children (Table 1). Prior to hospitalisation and virus isolation, both children had received antiviral treatment against influenza. The primary-school child aged 6 years who was infected with A/YOKOHAMA/87/2019 had been treated with a single oral dose of baloxavir on the day of symptom onset and fever resolved within one day of baloxavir administration. Face oedema had developed 2 days after baloxavir administration, although this patient had no underlying diseases. The child was diagnosed with nephritis and hospitalised.

The preschool child aged 5 years who was infected with A/YOKOHAMA/88/2019 had received oseltamivir 3 days after onset of illness, although its clinical benefit is greatest when administered within 48 hours of illness onset. Fever tended to resolve after oseltamivir administration. This child had no underlying diseases but was subsequently hospitalised for pneumothorax and subcutaneous emphysema. No epidemiological link was identified between these patients.

        (SNIP)

        Discussion

In this study, we detected two PA I38T mutant A(H3N2) viruses respectively from two hospitalised children. In addition, during our nationwide monitoring, we detected nine PA I38T or I38M mutant A(H3N2) viruses from baloxavir-treated patients (Table 3).

All of these viruses were isolated in humanised MDCK cells, hCK cells, which express high levels of α2, 6-sialoglycans and very low levels of α2, 3-sialoglycans [6]. Deep sequencing analysis revealed that eight of these viruses possessed mixed PA I38T/I or I38T/M/I substitutions in the clinical specimens and six of these eight possessed increased proportion of the PA I38T or I38M substitution after virus isolation.

A previous study reported that influenza A/Victoria/3/75(H3N2) viruses with the PA I38T, I38M, or I38F substitutions showed less growth capability than the wild-type virus in cell culture [2]. In contrast, our results indicate that recently circulating A(H3N2) viruses with the PA I38T or I38M substitution grow well, at least in cell culture.

(Continue . . . )

As mentioned earlier, 10 days ago Japan's National Institute of Infectious Diseases (NIID) published a bulletin which described two additional non-baloxavir-treated cases discovered to carry the H3N2 PA138T resistance mutation.

A slightly syntax-challenged translated excerpt from a much longer report follows:

Detection of Valoxavir-Resistant Mutant Virus from Patients Untreated with the Novel Anti-Influenza Drug Valoxavir
 
(The bulletin publication date 2019/3/12)

(Excerpt)

In this paper, we report that 3 strains of valoxavir resistant mutant virus were detected from 3 patients who did not receive valoxavir by analysis of A (H3N2) virus collected from November 2018 to February 2019.

The PA I 38 T resistant mutant virus (A / triple / 41/2018) was detected in a 12-year-old child at the Mie Prefectural Institute of Public Health and Environment in November 2018. In a sporadic case, the patient consulted a medical institution the day after the onset of illness and was diagnosed with influenza. The patient had not received anti-influenza medication prior to collection of the sample, and had not received valoxavir.

PA I38T resistant mutant virus (A / Yokohama / 88/2019 and A / Yokohama / 87/2019) are from the children aged 5 and 6 who are hospitalized with influenza at Yokohama City Inst. Of Health in January 2019 was detected.

A 5-year-old child who A / Yokohama / 88/2019 was detected visited a medical institution on the 4th day of onset, and administration of oseltamivir was started and she became apt to have fever, but on the 7th day of onset respiratory symptoms I was admitted and hospitalized.

Before the onset of the disease, there was a flu outbreak in a kindergarten that attended a school. She was sampled at the time of admission but received oseltamivir and had not been treated with valoxavir. On the other hand, a 6-year-old child whose A / Yokohama / 87/2019 was detected received valoxavir administration on the day of onset and healed on the next day. I was admitted to the hospital because of an abnormality.

Specimen collection was on day 6 of valoxavir administration and was considered to be a resistant mutant virus resulting from valoxavir administration. A / Yokohama / 87/2019 and A / Yokohama / 88/2019 have different gene sequences and it was judged that there was no direct transmission of infection between the two patients, but from the onset of the 5-year-old patient The mother developed influenza on the 4th day, the father on the 5th day, and the sister on the 6th day, and the sister developed influenza on the second day after the onset of the 6-year-old patient. There is.

The PA I 38 T resistant mutant virus (A / Kanagawa / IC18141 / 2019) was detected from the 8-month-old baby at the National Institute of Infectious Diseases in February 2019. The patient consulted a medical institution the day after the onset of illness and administration of oseltamivir was started. The patient had a fever of 38.9 ° C at the time of medical examination, but it dropped to below 37 ° C the day after the administration of oseltamivir in the upper half of the 37 ° C the next day. The patient did not receive anti-influenza medication prior to collection of the sample and had not received valoxavir, but on the day before onset, the brother developed influenza and received valoxavir, and transmission of infection among brothers is possible. There is sex.

Since the PA I38T resistant mutation is considered to be a mutation caused by valoxavir administration, the three strains of PA I38T resistant mutant viruses (A / triple / 41/2018, A detected from the above three patients who did not receive valoxavir) / Yokohama / 87/2018 and A / Kanagawa / IC18141 / 2019) suggest the possibility of transmission from valoxavir-treated patients.

(Continue . . . )

 

In 2008 seasonal H1N1 went from being almost 100% sensitive to Oseltamivir to nearly 100% resistant (see CIDRAP On the CDC Change Of Advice On Tamiflu) in a matter of months.  

It was only the unexpected arrival of a new, oseltamivir-sensitive H1N1 pandemic virus the following spring - replacing the resistant virus - that averted a crisis.

While three cases does not a crisis make, the discovery of additional resistant viruses in children who had not received Baloxavir - combined with the finding that `recently circulating A(H3N2) viruses with the PA I38T or I38M substitution grow well, at least in cell culture' - means that researchers in Japan, the United States, and elsewhere are going to have to maintain a sharp lookout for additional cases.  

Stay tuned.

 

Japan MAFF: 12th Farm Outbreak Of Classical Swine Fever (CSF)

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While China, Vietnam, and Eastern & Central Europe deal with rapidly spreading African Swine Fever, since September of last year Japan has been contending with the return - after an absence of 26 years - of Classical Swine fever.

Both diseases are highly contagious among pigs, and can be economically devastating for pork producers, but neither disease poses a direct human health threat.

Today Japan's MAFF announces their 12th farm (and 10th in Gifu Prefecture) to test positive for the disease.

Confirmation of suspected affected animals of swine fever in Gifu Prefecture, about (12 case was in Japan)
2019 March 23,

the Ministry of Agriculture, Forestry and Fisheries

Today, suspected affected animals of swine fever has been confirmed in a pig farm in Gifu, Yamagata Prefecture.

We are taken all possible measures for the quarantine measures for the disease.

The farm, has been located within the movement restricted area of 11 cases eyes of the farm, March 5 days later, we do not the movement of breeding pigs.

Interview in the field, thank you for your cooperation as strictly refrain from such that there is a risk that cause the spread of the disease.

1. Overview of the occurrence farm

Location: Gifu Prefecture Yamagata City
breeding situation: 2,034 head

2. Background

(1) Gifu Prefecture, March 22 (Friday), from the farm, received a report of a feeding pigs and has a loss of appetite, we conducted a site inspection by animal health inspectors.

(2) the same day, because the suspicion of swine fever is caused by the inspection at the Livestock Hygiene Service Center, was subjected to a thorough examination, today (March 23 (Saturday)), has been confirmed to be a suspected affected animals of swine fever directly below.

(Continue . . . )

 
The twelve farm outbreaks to date only tell part of the story, as the virus is also spreading through wild boar in central Japan. The most recent OIE Notification (March 15th #29853) - Japan's 20th since the outbreak began - adds nine more wild boar to the list of CSF positive pigs.

From the Epidemiological Comments:

1. The 11th affected farm (Yamagata city in Gifu, 06/03/2019) Disinfection of contaminated materials, tools and facilities was completed on the 9th March at the affected farm.

2. The 8th affected farm (Toyota city in Aichi, 05/02/2019) Removal of movement restriction zone (MRZ): On 00:00 of 13th March, movement restrictions, which were established within 3km radius of the affected farm, were lifted as 28 days have passed after the completion of full implementation of control measures (stamping out, disinfection etc.) at the 8th affected farm. 

3. The 10th affected farm (Mizunami city in Gifu, 18/02/2019) Removal of shipment restriction zone (SRZ): On 00:00 of 13th March, shipment restrictions, which were established within 3-10 km radius of the affected farm, were lifted as 17 days have passed after the completion of full implementation of control measures (stamping out, disinfection etc.) at the 10th affected farm.

Summary of the wild boar surveillance 

• As of the 14th of March, 874 wild boars (115 dead and 759 captured) in Gifu prefecture have been tested and 215 (71 dead and 144 captured) were found to be positive for CSF virus (CSFV) by RT-PCR since 13th of September.
•  122 wild boars (15 dead and 107 captured) in Aichi prefecture have been tested and 12 were found to be positive (one dead and 11 captured) for CSFV by RT-PCR since 14th of September. 
• Among the other prefectures, 246 wild boars (223 dead and 23 captured) in 40 prefectures were tested and all were found to be negative for CSFV by RT-PCR since the 14th of September. 

Until last September, Japan had been one of only 35 countries (see map below) that has been certified by the OIE as being free of the disease with their last outbreak reported in the early 1990s.

 With Japan's recent suspension, that number now stands at 34.

CDC FluView Week 11: Flu Season Continues Strong As H3N2 Continues To Climb

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Influenza activity, which showed signs of peaking twice earlier in the season (see ILI chart below), continues to reinvigorate itself with late season surge in H3N2 activity.

While most of the illnesses in this 2018-2019 winter flu season have been due to H1N1,in the past week, 65% of virus samples tested by the CDC were H3N2. The percentage of H3N2 viruses falling into the rising 3C.3a clade - which in week 44 only comprised 4% of H3N2 viruses sampled - has risen to 65%.

Even more remarkably, the CDC has analyzed 102 H3N2 viruses over the past two reporting weeks, and of those 92 (90%) belong to this rising clade.  A big reason why yesterday, the WHO Selected the Fall H3N2 Flu Shot Component: Clade 3C.3a.

A few excerpts from today's FluView report, followed by a snapshot estimate of this flu season's burden the public's health.

2018-2019 Influenza Season Week 11 ending March 16, 2019

All data are preliminary and may change as more reports are received.

An overview of the CDC influenza surveillance system, including methodology and detailed descriptions of each data component, is available at http://www.cdc.gov/flu/weekly/overview.htm.

Synopsis:

Influenza activity remains elevated in the United States. Influenza A(H1N1)pdm09, influenza A(H3N2), and influenza B viruses continue to co-circulate. Below is a summary of the key influenza indicators for the week ending March 16, 2019:

• Viral Surveillance:The percentage of respiratory specimens testing positive for influenza viruses in clinical laboratories increased slightly. Nationally, during the most recent three weeks, influenza A(H3) viruses were reported more frequently than influenza A(H1N1)pdm09 viruses and in HHS Regions 2, 4, 5, 6, 7, 8, 9 and 10.
• Virus Characterization:The majority of influenza viruses characterized antigenically are similar to the cell-grown reference viruses representing the 2018–2019 Northern Hemisphere influenza vaccine viruses. However, an increasing proportion of influenza A(H3N2) viruses are antigenically distinguishable from A/Singapore/INFIMH-16-0019/2016 (3C.2a1), a cell-propagated reference virus representing the A(H3N2) component of 2018-19 Northern Hemisphere influenza vaccines.
• Antiviral Resistance:The vast majority of influenza viruses tested (>99%) show susceptibility to oseltamivir and peramivir. All influenza viruses tested showed susceptibility to zanamivir.
• Influenza-like Illness Surveillance:The proportion of outpatient visits for influenza-like illness (ILI) remained at 4.4%, which is above the national baseline of 2.2%. All 10 regions reported ILI at or above their region-specific baseline level.
• ILI State Activity Indictor Map: 26 states experienced high ILI activity; 12 states experienced moderate ILI activity; New York City, Puerto Rico and eight states experienced low ILI activity; four states experienced minimal ILI activity; and the U.S. Virgin Islands and the District of Columbia had insufficient data.
• Geographic Spread of Influenza: The geographic spread of influenza in 44 states was reported as widespread; Puerto Rico and four states reported regional activity; the District of Columbia and two states reported local activity; the U.S. Virgin Islands reported sporadic activity; and Guam did not report.
• Influenza-associated Hospitalizations A cumulative rate of 47.1 laboratory-confirmed influenza-associated hospitalizations per 100,000 population was reported. The highest hospitalization rate is among adults 65 years and older (146.0 hospitalizations per 100,000 population).
• Pneumonia and Influenza Mortality: The proportion of deaths attributed to pneumonia and influenza (P&I) was below the system-specific epidemic threshold in the National Center for Health Statistics (NCHS) Mortality Surveillance System.
• Influenza-associated Pediatric Deaths: Eight influenza-associated pediatric deaths were reported to CDC during week 11.

While this year's estimated flu burden still pales when compared to last year's severe H3N2 season, the numbers continue to climb, and the season may have several more active weeks ahead. 

 

OIE: Multiple Outbreaks Of LPAI H7N4 In Cambodian Poultry

Credit CDC

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In February of 2018 in Jiangsu China Reports 1st Novel H7N4 Human Infection, we learned of the first known human infection with a novel H7N4 virus which resulted in a 3-week hospitalization for a 68 year old woman in Jiangsu Province for severe pneumonia. 

Since then, no new cases have been reported, but we have learned a bit more about the virus.

Eight days later, in WHO: Genetic Characteristics Of Avian H7N4, we learned this AI virus was a purely avian LPAI H7 strain - distinct from A(H7N9) - although it carried the PB2  637K marker associated with mammalian adaptation.

That same day the World Health Organization released a Risk Assessment, which read in part:

It is possible that additional human cases of avian influenza A(H7N4) will be detected, however only one human case has been detected so far, and information on the circulation of avian influenza A(H7N4) in birds is not currently available. Further information needs to be gathered to increase the confidence in this assessment.

It's been a year, and very little else has been reported on the H7N4 virus, likely due - at least, in part - to China's massive H5+H7 poultry vaccination campaign, which began about 20 months ago. 

Since then, avian flu reports out of China have been greatly subdued.

Although it isn't exactly a stop-the-presses! moment, today the OIE has been notified of multiple detections of LPAI H7N4 in poultry in southeastern Cambodia, relatively near their border with South Vietnam. 

While details on these outbreaks are sparse, somewhat surprisingly, these outbreaks are listed as having an onset date of February 2018, but are only now being announced.

I suspect that routine samples were collected from poultry a year ago, put into a low priority queue, and have only recently been tested. Hopefully we'll get more details on exactly what happened.

Also, it isn't immediately apparent how closely related these H7N4 avian viruses are to the one reported in China in early 2018. Again, hopefully we'll get a more thorough analysis.

First, a brief announcement in the Vietnamese press.

New strains of avian influenza virus appeared armpit Vietnam

Friday, 03/22/2019 - 12:13

 

(PLO) - International Forestry and Agriculture Organization (FAO) said the H7N4 bird flu virus has emerged in Cambodia. This new strain previously detected in China in 2018.

 

FAO assessment new bird flu strain that can appear anywhere and anytime, so Vietnam needs to maintain a research laboratory capacity to detect and prevent.

Before this warning, in the Conference national plans to deploy anti-bird flu period 2019-2025 by the Department of Animal Health held on 22-3, Deputy Minister of Agriculture and Rural Development Phung Duc Tien that can not be ignored, subjective in prevention.

Under the plan approved by the Prime Minister in mid-May 2-2019, the veterinary service will focus not to the branch block, new dangerous viruses infecting Vietnam. With the current strain, to vaccinate at least 80% of the total. Try to minimize or not arising cases of human avian influenza.

Epidemic of avian influenza A / H5N1 appeared in Vietnam in late 2003, then spread to the whole country. The period 2007-2013, each year to slaughter 200,000 poultry have spread to 42 people, dying from this virus. Since mid 2014, the epidemic is under control, reduce the number of poultry to be destroyed while 90,000 children each year, no patient deaths due to influenza A / H5N1 as well.

And some excerpts from today's OIE Notification:

Epidemiological comments 

Active surveillance conducted in collaboration between National Animal Health and Production Institute (NAHPRI) of the General Directorate of Animal Health and Production (GDAHP), Institut Pasteur du Cambodge and FAO in live bird markets and other high risk sites has identified multiple H7 low pathogenic virus in 2018. The susceptible population in each market was more than 100 and the cases were 1-10 per markets.

While today's report doesn't tell us much about the current dispersal of H7N4 viruses in southeast Asia, we now know that that this subtype was circulating in locations more than 2,700 km apart (see map below) in February of last year.

A sobering reminder of how little real-time data we really get on the evolution, and spread, of potentially dangerous avian flu viruses from many parts of the globe.