The Emerging Threat Of EV71

 

Photo Credit University of Iowa

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Although only recently making headlines in the mainstream media, Enterovirus 71 has been known for decades, and has been responsible for a number of severe disease outbreaks in small children, particularly across southeast Asia.

 

For some earlier blogs on this virus and some of the outbreaks it has caused, you may wish to revisit:

China: A Recombinant EV-71

China Sounds Alert Over EV-71 Virus

China: EV71 Claims 28th Victim, Authorities Warn of Possible `Mass Outbreak'

HFMD Outbreak In China Spreads To 25,000 Children

 

But it has been the recent outbreak in Cambodia (see Updating The Cambodian EV71 Story) that has helped to propel this virus into the public’s consciousness, and we are now seeing reports in the media on practically a daily basis.

Today, several reports, including one from the Philippines where Assistant Health Secretary Eric Tayag ominously warns that even as the world seeks to eradicate polio from the last four countries, that the EV71 virus may soon become `the new polio’.

 

EV-71 is the 'new polio,' health experts warn

by Rappler.com

Updated 07/17/2012 7:33 PM

MANILA, Philippines - Two children in the Philippines have been tested positive for "human enterovirus," but the strain is not similar to the EV-71 that has killed kids in Cambodia, the Department of Health said Tuesday, July 17.

(Continue . . .)

 

 

A bit premature perhaps, given that the numbers of severe EV71 infections currently pale in comparison to the horrific spread of Polio during the first half of the 20th century.

 

But there are some valid comparisons between the two viruses.  Both are highly contagious, and both strike predominantly in young children and can cause serious – even fatal – neurological damage. 

 

From The Lancet, we’ve this 2008 report that makes a similar comparison.

 

Enterovirus 71 infection: a new threat to global public health?

The Asia-Pacific region has seen more frequent and widespread outbreaks of enterovirus 71 infections in the past decade. Clinicians and researchers are calling for a better understanding of the evolution of such epidemics and for more proactive international public health polices. Jane Qiu reports.

Enterovirus 71 (EV71), a single-stranded RNA virus that belongs to the same category as poliovirus, has made another comeback in many parts of Asia. The reported frequency of EV71 infections are rising on a weekly basis: in Hong Kong, the number of cases reached 79 by late August, the highest in a decade. In some cases, EV71 infections cause hand—foot—mouth disease (HFMD), a common, contagious disease that usually affects children and that is characterised by flu-like symptoms; rash on hands, feet, and buttocks; mouth ulcers; poor appetite; and vomiting and diarrhoea.

 

However, HFMD can be life threatening, particularly if the virus causes inflammation of the brain stem, which can progress to heart failure and pulmonary oedema.

 

(Continue . . .)

 

 

With no vaccine, and no specific antiviral treatments available, the focus is on stopping the spread of the virus through good hygiene, and when needed, school closures.

 

Today, from Thailand’s The Nation, we get this report indicating that a number of schools are being closed due to HFMD.

 

 

29 Bangkok schools suspend classes following HFMD outbreak

July 17, 2012 6:46 pm

 

At least 29 schools in Bangkok have suspended some of their classes or shut down their whole facilities in the wake of the hand, foot, and mouth disease or HFMD outbreak.

 

"In Bangkok, most patients are young children aged not over four years old," Dr Wongwat Liewlak said Tuesday as the head of Bangkok Metropolitan Administration (BMA) Communicable Diseases Control Division.

According to the Public Health Ministry, 12,581 people have come down with the HMFD in Thailand between January 1 and July 9 this year. There is no report of casualties.

 

Another report out of Thailand, carried by Xinhua News, indicates:

 

Top Bangkok primary school closes due to hand, foot and mouth disease

Updated: 2012-07-17 15:46:00

(Xinhua)

BANGKOK, July 17 (Xinhua) -- Bangkok's top-rated Chulalongkorn University Demonstration Elementary School suspended classes from Tuesday through Friday after a number of students were infected with hand, foot and mouth disease, Thai News Agency reported.

 

Chalermpol Daoruang, the school's deputy director, said that the temporary closure came after an unspecified number of Grade 1 and 2 students were diagnosed with hand, foot and mouth disease ( HFMD).

(Continue . . .)

 

And yet another report, out of Taiwan today, CDC reports six new enterovirus cases. The good news: all but one of these cases have already been released from the hospital.

 

Whether EV71 turns out to be 2012’s disease-du-jour, or ends up becoming a pervasive public health problem remains to be seen.

 

It has the potential, but it may not have the `legs’.

 

Encouragingly, there does appear to be work going on to create a vaccine against EV71.  In the meantime, like everyone else, we’ll continue to watch the virus for signs of spread, or changes in its behavior.

»» Read More

EV71: Cambodia’s Prime Suspect

 

Photo Credit University of Iowa

 

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Although normally a mild childhood disease, HFMD (Hand, Foot, & Mouth Disease) has taken center stage in the media these past few days as one of the viruses (EV71) associated with that illness has been tentatively linked to dozens of deaths of Cambodian children over the past three months.

 

The epidemiological investigation is ongoing, with researchers looking for any possible complicating factors (or changes to the virus) that might explain the unusually high mortality rate being reported with this outbreak. 

 

We should know more in a few days, but as you’ll see, the EV71 virus doesn’t need any help to be deadly. 

 

HFMD can be caused by a variety of viruses, and most of the time, it is mild and only rarely requires medical attention.

 

The most common cause of the illness is the Coxsackie A16 virus, and more rarely the Coxsackie A10 virus. In recent years, we’ve also seen the emergence of the Coxsackie A6 virus which has been linked to somewhat more severe HFMD cases (see MMWR: Coxsackievirus A6 Notes From The Field).

 

But it is Enterovirus 71 that has been linked to the most severe cases of HFMD – particularly across Asia - with serious outbreaks recorded over the past dozen years in places like China, Taiwan, Malaysia, Hong Kong and most recently, Vietnam.

 

In addition to the classic HFMD symptoms, this virus has been known to produce serious neurological illness, including life threatening encephalitis. 

 

You can find more details on HFMD, and EV71, in the World Health Organization’s Hand, Foot and Mouth Disease Information Sheet, from which I’ve excerpted the following:

 

• HFMD is usually a mild disease, and nearly all patients recover in 7 to 10 days without medical treatment and complications are uncommon.
  • Dehydration is the most common complication of HFMD infection caused by coxsackieviruses; it can occur if intake of liquids is limited due to painful sores in the mouth.
  • Rarely, patients develop "aseptic" or viral meningitis, in which the person has fever, headache, stiff neck, or back pain, and may need to be hospitalized for a few days.
• HFMD caused by EV71 has been associated with meningitis and encephalitis, and on occasion can cause severe complications, including neurological, cardiovascular and respiratory problems. Cases of fatal EV71 encephalitis have occurred during outbreaks.

 

While the recent outbreak in Cambodia has raised alarms around the world, deadly outbreaks of EV71 are nothing new.  Last May, in CDC Issues HFMD Travel Notice For Vietnam, we looked at an outbreak that had claimed more than 20 lives.

 

In the News
Hand, Foot, and Mouth Disease in Vietnam

Released: May 25, 2012

What Is the Current Situation?

As of April 29, 2012, the Vietnam Ministry of Health has confirmed nearly 40,000 cases of hand, foot, and mouth disease (HFMD) since the beginning of 2012. Cases have occurred in 63 provinces, and 20 deaths (all in children under 5) have occurred in 10 provinces.

(Continue . . .)

 

The CDC also provides several  multimedia products related to hand, foot, and mouth disease.

 

• CDC Feature: Hand, Foot, & Mouth Disease
  An article that provides the basics about hand, foot, and mouth disease, who is commonly affected, symptoms, how it spreads, and ways to prevent it.
• Podcast: Hand, Foot, and Mouth Disease
  A CDC pediatrician and dad talks about hand, foot, and mouth disease, its symptoms, and tips to prevent your family from getting this disease.

 

Similarly, we’ve seen reports this week indicating that Hand, foot, mouth disease kills 240 in China.

 

We are seeing reaction to the Cambodian outbreak from several health departments across Asia, including Hong Kong, Thailand, and the Philippines.

 

First, Hong Kong’s CHP (Centre for Health Protection) which sent out this Update on An Unknown Disease in Cambodia letter to doctors in the region on July 9th, which asks that doctors notify the CHP of any suspected cases with recent travel history to Cambodia.

 

Possibly related, the CHP is reporting on Two cases of severe paediatric enterovirus infection, although the causative virus is not indentified.

 

In Thailand, The Nation newspaper is reporting that the MOH has instructed schools to close if an unusual number of HFMD cases are reported.

 

Disease warning for schools

The Nation July 10, 2012 5:47 pm

The Public Health Ministry on Tuesday instructed schools and nurseries nationwide to close if they find that students in five classes or more have contracted hand, foot and mouth disease.

(Continue . . . )

 

And perhaps the most proactive of all is the Philippines, where the Department of Health has ordered increased surveillance at airports, and has declared  EV-71 to be a notifiable disease. 

 

Here is the official press release:

 

DOH MAKES ENTEROVIRUS-71 INFECTION AS A NOTIFIABLE DISEASE

July 10, 2012

(Press Release – 10 July 2012)

Health Secretary Enrique T. Ona instructed today the Department of Health (DOH) National Epidemiology Center to include Enterovirus-71 (EV-71) infection as a notifiable disease in the country. This will compel all health providers especially physicians to report individual cases or even outbreaks.

 

“Mandatory notification will improve monitoring of EV-71 infections and ensure that necessary measures are in place to guarantee that the Philippines is free from the highly fatal severe form of EV-71 infections that have claimed the lives of at least 60 children in Cambodia since April this year,” Ona said.

 

Also, the DOH and the World Health Organization (WHO) clarified today that the Cambodian EV-71 was of the encephalitis type and not hand foot and mouth disease (HFMD) as earlier reported. Affected Cambodian children generally presented with fever followed by rapid respiratory deterioration and impaired consciousness. Death occurred 24 hours from hospital confinement.

 

EV-71 causes different diseases of varying intensity. These include the often mild hand, foot and mouth disease (HFMD), acute respiratory disease, acute flaccid paralysis (polio-like) and the deadly brainstem encephalitis. HFMD is characterized as a self-limiting illness presenting with fever and accompanied by skin lesions or rashes.

 

EV-71 infections do occur in the country but are reported with irregularity. Fatal EV-71 infection is still very rare in the Philippines.

 

Proper disposal of baby diapers or human waste, strict personal hygiene and regular hand washing prevent viral spread. The virus is known to be excreted in the feces since it is found in human intestines.

 

 

The DOH urges parents and day-care personnel to clean and disinfect toys and teaching tools that are easily shared with other children. This can prevent EV-71 infections, as there are no known effective drugs or vaccines.

 

 

‘There is still no travel restriction to and from Cambodia and incoming passengers will be subjected to thermal screening upon arrival in all international airports as a routine quarantine procedure,” the health chief concluded.

 

The statement above, that the `(WHO) clarified today that the Cambodian EV-71 was of the encephalitis type and not hand foot and mouth disease (HFMD)’ is something I’ve not been able to locate on the WHO site yet.  

 

And last, but certainly not least, Lisa Schnirring of CIDRAP NEWS wrote a detailed report last night on the Cambodian outbreak, which you can read at:

 

Enterovirus 71 cited in puzzling Cambodian infections

Lisa Schnirring Staff Writer

Jul 9, 2012 (CIDRAP New) – Lab analysis in the mysterious recent illnesses and deaths of dozens of Cambodian children pointed to enterovirus 71 (EV-71), a virus that causes hand, foot, and mouth disease (HFMD) and can lead to severe complications in some patients, the World Health Organization (WHO) announced today.

(Continue . . .)

 

 

The peak season for HFMD is summer and fall, which suggests that we will be hearing about outbreaks of EV71, and other HFMD viruses, for months to come.

»» Read More

What Goes Around, Comes Around

 

 

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With bird flu outbreaks among poultry and wild birds increasing across South Korea and Japan (North Korea and possibly China are unknown factors), other Asian countries that see migratory bird visitations over the winter are understandably on the alert.

 

Today, a news release form the National News Bureau of Thailand, Public Relations office that reflects their concern. 

 

Bird flu fear sparks warning across the country

BANGKOK, 30 January 2011 (NNT)-Public Health Minister Jurin Laksanawisut has instructed public health services across Thailand to warn people of a possible outbreak of bird flu in human, although there has been no report on any one contracting the disease so far.

 

Following an unidentified cause of death of 100 chickens in Sam-Chuk district, Suphan Buri province, local residents fear H5N1 or commonly known as bird flu was the reason. However, an autopsy on dead chickens are still underway. Mr. Jurin has taken a precautionary step and instructed health services to coordinate with officers from the Department of Livestock and the Department of Agriculture for help.

 

According to the Health Minister, it is important that people are aware of risks and know how to protect themselves against the flu. People have also been warned not to come in contact with dead poultry. Mr. Jurin said even though Thailand has been free of the flu since 2006 ,the Ministry of Public Health will continue to monitor the disease to safeguard the health of the Thai people

 

We’ll have to wait to hear if this turns out to be anything, but it gives you an idea of how seriously officials are taking these latest outbreaks.

 

Japan, Korea, and Thailand are part of the great East Asian - Australasian Flyway. All three countries are the winter home for many species of migrating birds, many of which spend their summers in Siberia, China, and Mongolia. 

 

There are, however - overlaps between these flyways - enabling pathogens to be carried from one to another.

 

 

In what may turn out to be a related story, yesterday in an EID dispatch (see EID Journal: H5N1 Branching Out) we saw a report out of Qinghai, China indicating that a new (for them) clade 2.3.2  of H5N1 bird flu was reported in wild birds near major migratory nesting grounds back in 2009 (admittedly, news travels slow out of China).

 

Clade 2.3.2 isn’t new, of course. 

 

It’s been circulating - primarily among poultry in Vietnam and parts of China - since the middle of the last decade, and started showing up in wild bird surveillance a couple of years later.

 

In March of 2009, the CDC’s EID Journal published the following report.

 

Characterization of Avian Influenza Viruses A (H5N1) from Wild Birds, Hong Kong, 2004–2008

Gavin J.D. Smith,1 Dhanasekaran Vijaykrishna,1 Trevor M. Ellis, Kitman C. Dyrting, Y.H. Connie Leung, Justin Bahl, Chun W. Wong, Huang Kai, Mary K.W. Chow, Lian Duan, Allen S.L. Chan, Li Juan Zhang, Honglin Chen, Geraldine S.M. Luk, J.S. Malik Peiris, and Yi Guan

(EXCERPT)

Genetic and antigenic characterization of 47 HPAI (H5N1) viruses isolated from dead wild birds in Hong Kong showed that these isolates belonged to 2 antigenically distinct virus groups: clades 2.3.4 and 2.3.2.

 

Although research has shown that clade 2.3.4 viruses are established in poultry in Asia, the emergence of clade 2.3.2 viruses in nonpasserine birds from Hong Kong, Japan, and Russia raises the possibility that this virus lineage may have become established in wild birds.

 

 

Passerine birds encompass `perching birds’ & songbirds, while nonpasserine birds include ducks, swans, storks, ostriches, aquatic water fowl, quail, turkeys, and gulls . . . among many others.

 

In Late November of 2010, after 2 and 1/2 years without an outbreak, the H5N1 virus was detected at a poultry farm in Japan (see Japan: Bird Flu Investigation At Poultry Farm).  

 

Subsequently, the OIE WAHID follow up report # 1 identified the strain as being clade 2.3.2.  A hat tip to Ironorehopper for archiving the following information on his website:

 

Highly pathogenic avian influenza, Japan (WAHID Interface - OIE World Animal Health Information Database, Dec. 09 2010, edited

Epidemiological comments

• It is considered that the virus was carried to the surroundings of the farm by migratory birds because the outbreak occurred in a season when migratory birds came flying from the north to Lake Nakaumi nearby the farm.

• The virus might have invaded the affected henhouse through wild birds, wild animals or others.

• The National Institute of Animal Health affirmed by comparison of gene sequence that the isolate is classified into clade 2.3.2 and a closely-related strain with the virus isolated from faeces of migratory wild ducks in Hokkaido in October 2010.

• The homology between these viruses is 99.6%.

 

We’ll have to await further phylogenetic analysis from other farms in Japan, Korea, and elsewhere to know for certain .  .  .  but it certainly appears that the  2.3.2 clade has become well established in migratory birds.

 

While that in itself may not be a game changer, it is a reminder that the bird flu virus isn’t just a moving target.

 

It is actually a half dozen (or more) moving targets.  And that just counts the H5N1 clades.

 

With myriad influenza A viruses comingling, swapping genetic material, and continually trying out new genetic combinations in order to make a better, more `fit’ virus – it is imperative that we do what we can to improve global pathogenic surveillance and reporting.

 

Because experience has shown us, diseases that go around in one part of the world, have a nasty habit of eventually coming around to the rest of the planet.

»» Read More

Not One Of The Usual Suspects

 

 

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A story today out of Thailand that blames gulls, not storks, for introducing bird flu to that nation and possibly spreading it across south east Asia.

 

 

Using satellite telemetry, researchers have detailed the the complete migratory routes of the brown headed gull (Larus brunnicephalus), which summers in central Asia and winters on the tropical coast and inland lakes of southern Asia.

 

They’ve also detected the H5N1 virus in some small percentage of these migrating gulls, leading them to believe that it is the brown headed gull that has spread the virus to Thailand.

 

First a link to the news  report, then some follow up.

 

Study blames gulls, not storks, for bringing in bird flu

By Pongphon Sarnsamak
The Nation
Published on September 3, 2010

A study has found that the bird that carried the influenza virus H5N1 into Thailand was a gull, not the openbill stork.

 

 

Those with good memories may recall that last June I ran a report on H5N1 Bird Deaths In Tibet. The China Tibet Information Center cited the deaths of 171 wild bird from around Naqu Lake, and listed the species as:

 

• 141 brown-headed gulls
• 27 bare-headed geese
• 1 chough
• 1 wigeon 

 

And if we go back to 2007, during a time when H5N1 was making inroads into Western Europe, one of the concerns mentioned was the Black Headed Gull, as I wrote of in UK Vet Warns Of Migratory Bird Threat.

 

The whole migratory-birds-spreading-H5N1 issue is a contentious one, with some groups defending wild birds and pointing their fingers at poultry producers and smuggling.

The poultry industry generally cries fowl (sorry), and blames wild birds instead.

 

As a dispassionate observer, without a bird in this fight, I can see how both contribute to the spread of the virus.  Which I suspect makes me not very popular in either camp.

 

Up until now, gulls have been a low profile suspect in the spread of bird flu.  Now, with this new study, they may need to come under more scrutiny.

»» Read More

Thailand: Investigating Thousands Of Dead Storks

 

 

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Whenever we hear of large die-offs of birds, particularly in Asia, we immediately think of H5N1.

 

But we’ve seen bird die-offs in various parts of the world that turned out to be due to something other than bird flu. While suspicious, this incident may have been caused by environmental toxins or even deliberate poisoning.

 

Since bird flu is a possibility, we’ll obviously watch with interest for any laboratory test results that come out of this.

 

This report from the Bangkok Post.

 

 

 

Thousands of storks die, bird flu cause debated

• Published: 2/05/2010 at 02:11 AM
•  

Thousands of openbill storks in Phra Nakhon Si Ayutthaya's Phak Hai district have died, with avian influenza thought to be a possible cause.

 

BIRDS IN HAND: A farmer shows carcasses of two openbill storks among thousands which have died in Ayutthaya’s Phak Hai district. Residents fear bird flu is the cause of the deaths. PHOTO: SUNTHORN PONGPAO

A vast wasteland in tambon Khok Chang of Ayutthaya is home to tens of thousands of Asian openbill storks (nok pakhang). It is one of the largest flocks of birds in Ayutthaya.

 

A few days ago thousands of Asian openbill storks died without apparent cause.

 

Residents are worried the flock might have been infected with the bird flu virus as Phak Hai district was one of many areas nationwide reported with the virus outbreak last year.

 

They want authorities to investigate why the birds have died.

 

<SNIP>

 

 

In his view, the bird flu virus was unlikely to be the cause of the deaths, as it usually spreads in the early winter season, not in the summer.

 

However, it was not being ruled out in the investigation, said the district chief.

»» Read More