Wednesday, July 23, 2014

EID Journal: H3N2v Swine To Human Transmission At Agricultural Fairs – 2012




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I hadn’t planned on writing another swine variant influenza-related blog again so soon (see yesterday’s blog CDC: Measures to Minimize Influenza Transmission at Swine Exhibitions, 2014), but today the CDC’s EID Journal has posted an analysis of the 2012 outbreak of H3N2v associated with attendance of agricultural fairs in Ohio in 2012.


Although only 19 swine variant flu infections were reported last year,  in 2012 more that 300 cases were reported, with nearly all linked to fairgoers, mostly in Indiana & Ohio.


State & local  fairs have instituted inspections for any signs of illness in livestock – but as we’ve discussed previously (see Asymptomatic Pigs: Revisited) - pigs can sometimes carry these viruses without showing any outward signs of infection.


The concern with these variant swine flu infections, as it is with any animal flu that jumps to humans, is that it gives the virus another opportunity to better adapt to human physiology.


While humans have a long history of exposure to seasonal H3N2 flu viruses, research has shown only limited community immunity to these variant strains (see CIDRAP: Children & Middle-Aged Most Susceptible To H3N2v). The good news is that while several hundred infections were recorded in 2012, sustained and efficient community transmission was not observed, and for the most part, the virus only caused mild to moderate illness.


Today’s study confirms the link between fairs with H3N2v infected pigs, and human cases, and confirms that the strains detected in humans, and those detected in pigs, were > 99.7% identical.  Follow the link below to read:.


Swine-to-Human Transmission of Influenza A(H3N2) Virus at Agricultural Fairs, Ohio, USA, 2012

 Andrew S. BowmanComments to Author , Sarah W. Nelson, Shannon L. Page, Jacqueline M. Nolting, Mary L. Killian, Srinand Sreevatsan, and Richard D. Slemons

Author affiliations: The Ohio State University, Columbus, Ohio, USA (A.S. Bowman, S.W. Nelson, J.M. Nolting, R.D. Slemons); Ohio Department of Health, Columbus (S.L. Page); US Department of Agriculture National Veterinary Services Laboratories, Ames, Iowa, USA (M.L. Killian); University of Minnesota, Saint Paul, Minnesota, USA (S. Sreevatsan)


Agricultural fairs provide an opportunity for bidirectional transmission of influenza A viruses. We sought to determine influenza A virus activity among swine at fairs in the United States. As part of an ongoing active influenza A virus surveillance project, nasal swab samples were collected from exhibition swine at 40 selected Ohio agricultural fairs during 2012.

Influenza A(H3N2) virus was isolated from swine at 10 of the fairs. According to a concurrent public health investigation, 7 of the 10 fairs were epidemiologically linked to confirmed human infections with influenza A(H3N2) variant virus. Comparison of genome sequences of the subtype H3N2 isolates recovered from humans and swine from each fair revealed nucleotide identities of >99.7%, confirming zoonotic transmission between swine and humans.

All influenza A(H3N2) viruses isolated in this study, regardless of host species or fair, were >99.5% identical, indicating that 1 virus strain was widely circulating among exhibition swine in Ohio during 2012.

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Swine are highly susceptible to a variety of flu viruses (human, swine, avian) - and are viewed as excellent `mixing vessels’, allowing viruses to reassort into new hybrid strains.

Reassortant pig[6]


While a handful of novel swine variant flu infections that don’t appear to transmit efficiently may not sound like a big deal, as the authors of this paper point out, Agricultural Fairs provide a favorable environment for multiple swine flu viruses to get together. They write:


Swine-to-human transmission and human-to-swine transmission of influenza A virus are known to occur at fairs (28), highlighting the fact that swine in this setting are potentially exposed to multiple lineages of influenza A viruses simultaneously, making fairs ideal locations for genomic reassortment and novel virus formation.


And not only can swine pass flu viruses on to people, people can pass flu viruses on to swine.  Something we saw happen around the world after the 2009 H1N1 pandemic virus emerged and began transmitting in humans. 


This bi-directional transfer of influenza viruses allows for even greater mixing and matching of genes, and explains how the H3N2v virus picked up the M (matrix) gene from the 2009 H1N1pdm virus in 2012.


The authors write:


The results of this study support previous calls for enhanced surveillance of influenza A viruses among swine, especially at high-risk swine–human interfaces

For more on swine variant influenza viruses, and why they matter, you may wish to revisit:


J. Virol: Continued Reassortment Of Swine Flu Viruses With Genes From pH1N1 In China
Keeping Our Eyes On The Prize Pig
Study: Novel & Variant Swine Influenzas In Korean Pigs
Seroprevalence Study: Avian Flu In Chinese Pigs

NASA: The Solar Super Storm Of 2012


Credit NASA



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Although it sounds like science fiction, two years ago today the earth narrowly (by cosmic standards) missed being hit by a massive solar storm that had the potential to knock our technology-dependant society back a hundred years. 


Back in 2010 we looked at the granddaddy of all known solar storms, the Carrington Event of 1859, and have revisited the topic a number of times since then, including:


NASA: Solar Max Is Finally Here

Solar Storms, CMEs & FEMA

NASA Braces For Solar Disruptions


While this solar cycle has produced the weakest solar maximum in living memory, it also produced – on July 23rd, 2012 – the largest known solar flare in 155 years.  A double-whammy solar flare that rivaled, or perhaps even exceeded, the power of the 1859 Carrington event.


One that - had it erupted a week earlier – would have directly impacted earth.


A Solar Flare is the brief, sudden release of radiation energy (X-Ray, Gamma Rays, & energetic particles (protons and electrons)) from the surface of the sun, generally in the vicinity of an active sunspot.


Solar flares are rated as either C Class (minor), M Class (Moderate), or X Class (extreme), and while the electromagnetic radiation they release can reach earth in only about 8 minutes time, their effects are mostly limited to disrupting communications and potentially damaging satellites.


A CME (Coronal Mass Ejection) is the ejection of a massive amount of plasma (electrons and protons & small quantities of helium, oxygen, and iron) from the the sun that may last for hours. Some of this plasma falls back into the sun, but trillions of tons can escape and if aimed in their direction, impact surrounding planets.


A CME may arrive on earth – 93 millions miles distant from the sun – 48 to 72 hours after it is observed, and spark a Geomagnetic Storm.   


While they pose no direct physical danger to us on the earth’s surface (we are protected by the earths magnetic field and atmosphere), a large CME can wreak havoc with electronics, power generation, and radio communications.


All of which brings us to a report, and 4 minute video, from NASA on this second anniversary of the earth almost getting clobbered by a `Carrington class’ solar storm.  First the links, and excerpts, and then I’ll be back with more.


Near Miss: The Solar Superstorm of July 2012

July 23, 2014: If an asteroid big enough to knock modern civilization back to the 18th century appeared out of deep space and buzzed the Earth-Moon system, the near-miss would be instant worldwide headline news.

Two years ago, Earth experienced a close shave just as perilous, but most newspapers didn't mention it. The "impactor" was an extreme solar storm, the most powerful in as much as 150+ years.

"If it had hit, we would still be picking up the pieces," says Daniel Baker of the University of Colorado. 


A ScienceCast video recounts the near-miss of a solar superstorm in July 2012. Play it

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From my perspective, that wasn’t a `near miss’ . . .  that was more of a `near hit’.

And even more sobering is this assessment, suggesting the odds of earth being struck by one of these solar super storms is actually a lot higher than we’ve previously thought.  Again from the NASA article:


In February 2014, physicist Pete Riley of Predictive Science Inc. published a paper in Space Weather entitled "On the probability of occurrence of extreme space weather events."  In it, he analyzed records of solar storms going back 50+ years.  By extrapolating the frequency of ordinary storms to the extreme, he calculated the odds that a Carrington-class storm would hit Earth in the next ten years.

The answer: 12%.


FEMA takes these solar storms seriously, and in 2010 held a major table-top exercise in anticipation of the upcoming solar maximum. According to a tweet from FEMA Director Craig Fugate back in 2011, they now include a solar weather update in their daily briefings.


A 30 page PDF file is available for download from the FEMA library on this exercise which envisioned a `near worst-case scenario’.

Managing Critical Disasters in the Transatlantic Domain - The Case of a Geomagnetic Storm


In 2009 the National Academy of Sciences produced a 134 page report on the potential damage that another major solar flare could cause in Severe Space Weather Events—Understanding Societal and Economic Impacts.


You can download the PDF for free from the National Academies Press at the above link.


In November of 2012 the U.S. National Intelligence Council released a report called  "Global Trends 2030: Alternative Worlds" that tries to anticipate the global shifts that will likely occur over the next two decades (see Black Swan Events). Making their top 10 list was:


7. Solar Geomagnetic Storms

"Solar geomagnetic storms could knock out satellites, the electric grid, and many sensitive electronic devices. The recurrence intervals of crippling solar geomagnetic storms, which are less than a century, now pose a substantial threat because of the world's dependence on electricity," the report says.


And last year Lloyds of London issued a risk assessment for the insurance industry called Solar storm Risk to the north American electric grid which calls another `Carrington’ class event inevitable, and the effects likely catastrophic, but the timing is unknowable.


Solar storms are among a number of plausible low-probability, high-impact events that – while not anything I would lie awake at night worrying about – are nevertheless worth considering as part of a balanced `All Hazards’ approach to preparedness.


In the 2011 OECD Report: Future Global Shocks report, the authors concentrated most of their attention on five highly disruptive future shock events.


  • A Pandemic
  • A Cyber Attack
  • A Financial Crisis
  • A Geomagnetic Storm
  • Social Unrest/Revolution

While all of these are difficult to prepare for, the truth is -  if you are well prepared for an earthquake or a hurricane - you are automatically in a better position to deal with the disruptions caused by these more exotic threats. Some resources to get you started on the road to `all threats’ preparedness include:






And some of my preparedness blogs, including:

When 72 Hours Isn’t Enough

The Gift Of Preparedness: 2013

In An Emergency, Who Has Your Back?

West Nile Virus, Dengue & Chikungunya Update


Credit CDC

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With MERS cases dwindling, and H7N9 and H5N1 basically in hibernation until fall, our attentions this summer have been focused largely on vector borne diseases that tend to flourish during warm weather months.   And three we are watching closely – WNV, Dengue & Chikungunya – are all relatively recent arrivals to the United States.



Over just a few years, WNV was able to spread from New York City, to every state in the lower 48.  In 2012, it caused nearly 3,000 cases of neuroinvasive WNV, and 286 deaths (see DVBID: 2012 Record Number Of West Nile Fatalities) – while the number of milder West Nile Fever cases probably exceeded 100,000.


From the USGS Factsheet on West Nile Virus


Each summer the CDC produces weekly surveillance reports on WNV activity (in humans, birds, and animals). And while these reports tend to lag behind actual events by a week or so (fatalities even more so, since some cases may be hospitalized for weeks before succumbing), they give us an excellent idea of how the WN season is progressing around the country.

While each WNV season varies as to its intensity and outbreak timing, so far we’ve not seen huge numbers of cases reported.  It is, however, usually the months of August and September that tells the tale.


Neuroinvasive cases (which present with meningitis, encephalitis, or flaccid Paralysis), while less common, are severe enough that they nearly always result in hospitalization and diagnosis, and so they are considered the best indicator of the scope of each year’s epidemic.  The number of `non-neuroinvasive’ cases counted is considered to represent only 1%-3% of the total.


Unlike Unlike Chikungunya and Dengue,  which primarily affect humans and non-human primates – WNV is mainly a disease of birds – which gives the virus a large natural reservoir to over winter in.  Humans and horses are considered `incidental’ infections (see WNV vs CHIKV: A Host Of Differences).

Dengue – which has increased tremendously around the world over the past 5 decades – has literally exploded in the Western Hemisphere since the year 2000 (see PAHO Five-fold increase in dengue cases in the Americas over the past decade), but thus far, has only made small inroads into North America.


In 2009 the Natural Resources Defense Council (NRDC) released a report outlining the risks that Dengue could re-establish itself in North America, that included this map showing the areas of the United States that are vulnerable to the introduction of Dengue.


Northern climes are far less likely to see dengue take hold than say, Florida or Southern Texas. Still, in the 18th and 19th century, both Malaria and Yellow Fever were endemic up and down the mid-Atlantic coast.


While we see hundreds of imported cases of dengue in the United States each year – each with at least the potential to seed local mosquito populations with the virus – so far locally acquired cases have remained rare.  The lack of an abundant non-human animal reservoir for the virus is likely partly responsible.


In 2003, a CDC EID study also found that economics and lifestyle may have a lot to do to with our lack of locally transmitted Dengue (see Texas Lifestyle Limits Transmission of Dengue Virus).


But given the availability of two competent mosquito vectors (Aedes Aegypti & Aedes Albopictus), and repeated introductions of the virus from travelers coming from regions where the virus is endemic, our luck in this matter may not last forever.


With well over 80 million visitors each year, many coming from regions where dengue, malaria, and chikungunya are endemic, Florida is the ideal place to monitor mosquito-borne diseases coming into the United States. The most recent Florida Arbovirus Surveillance Report (week 29) illustrates these repeated introductions:


International Travel-Associated Dengue Fever Cases: One case of dengue fever was reported this week in a person that had international travel: Brevard County. In 2014, 27 travel-associated cases have been reported.

Dengue Fever Cases Acquired in Florida:No cases of locally acquired dengue fever were reported this week. In 2014, a total of one case of locally acquired dengue fever has been reported.

International Travel-Associated Chikungunya Fever Cases: Six cases of chikungunya fever were reported this week in persons that had international travel. In 2014, 87 travel-associated cases have been reported.

Chikungunya Fever Cases Acquired in Florida:Two case of locally acquired chikungunya fever were reported this week in residents of Miami-Dade and Palm Beach Counties. In 2014, a total of two cases of locally acquired chikungunya fever have been reported.


Additionally, 28 cases of International Travel-Associated Malaria have been reported in Florida in 2014.  Over the past decade there have only been about a dozen locally acquired cases of Malaria in Florida.The only clusters were reported in 1996 (2 cases) and again in 2003 (8 cases) of locally acquired P. vivax malaria detected in Palm Beach County (see  Multifocal Autochthonous Transmission of Malaria --- Florida, 2003).


The new kid on the block is Chikungunya, and as with Dengue before it, it is now exploding across the Caribbean. The latest PAHO numbers show 436,586 cases since the outbreak began in December, but that is likely an undercount. Hardest hit has been the Dominican Republic, accounting for more than half of the total cases reported.


As with Dengue, the virus is maintained in the human population, and spread by mosquitoes – giving hope that the same environmental and economic factors that limit the spread of Dengue in the United States may also help suppress the spread of Chikungunya.


But the unknown factor is the Aedes Albopictus mosquito – aka the `Asian Tiger’ mosquito – which ironically also only recently arrived in North America.   First seen in Texas in the early 1980s (believed to have been imported on cargo ships from S.E. Asia), this aggressive biter can now be found from Florida to Maine, and swarms well into the Midwest.



In 2005 a mutation in the envelope protein gene (E1-A226V) of the Chikungunya virus was credited with allowing Aedes Albopictus or `Asian tiger’ mosquito to transmit the virus more efficiently (see A Single Mutation in Chikungunya Virus Affects Vector Specificity and Epidemic Potential), and has led to its rapid expansion across the globe.


It remains to be seen whether Chikungunya will act more like West Nile Virus – and become entrenched across large swaths of the United States – or act more like Dengue, and require constant reseeding from international travelers, only causing small localized clusters of infection.


The good news is that these mosquito-borne illnesses (and others, including SLEV, EEE, etc.) are largely preventable.


Florida’s Health department reminds people to always follow the `5 D’s’:


Tuesday, July 22, 2014

CDC: Measures to Minimize Influenza Transmission at Swine Exhibitions, 2014


Credit Wikipedia


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A little over three weeks ago, in Keeping Our Eyes On The Prize Pig, I wrote about the upcoming county & state fair season, and concerns that we could see a resurgence in Swine Variant Influenza infections in fairgoers this year.  Although only 19 such cases were identified in 2013, the previous year more that 300 cases were reported.


The CDC describes Swine Variant viruses in their Key Facts FAQ.

What is a variant influenza virus?

When an influenza virus that normally circulates in swine (but not people) is detected in a person, it is called a “variant influenza virus.” For example, if a swine origin influenza A H3N2 virus is detected in a person, that virus will be called an “H3N2 variant” virus or “H3N2v” virus.


Swine are highly susceptible to a variety of flu viruses (human, swine, avian) - and are viewed as excellent `mixing vessels’, allowing viruses to reassort into new hybrid strains.

Reassortant pig[6]

Here in North America we’ve been watching the evolution of several swine variant viruses (H1N1v, H1N2v, H3N2v) over the past few years, all of which have reassorted with - and picked up the M gene segment from – the 2009 H1N1 virus.  We’ve also seen similar reassortant viruses emerge in other parts of the world (see J. Virol: Continued Reassortment Of Swine Flu Viruses With Genes From pH1N1 In China).

While most reassortant viruses are evolutionary failures, the concern is that over time another swine variant virus might emerge – as did the 2009 H1N1 virus – and start another human epidemic or pandemic.


One strategy to try to prevent that from happening is limiting the number of humans that are exposed to these variant viruses, depriving the virus of opportunities to adapt to human physiology.  To that end, the CDC has issued the following advice for those planning to visit the fair:




For the past two years the CDC has also provided extended advice to exhibitors of swine, and those in charge of the venues, on their Guidance Associated with Fairs website.

Yesterday the CDC published a 6-page PDF file of Measures to Minimize Influenza Transmission at Swine Exhibitions, 2014, as prepared by the National Assembly of State Animal Health Officials (NASAHO) and the National Association of State Public Health Veterinarians (NASPHV).


Follow the link to download and read  the entire file.


National Assembly of State Animal Health Officials (NASAHO)
National Association of State Public Health Veterinarians (NASPHV)

Measures to Minimize Influenza Transmission at Swine Exhibitions, 2014

It is estimated that 150 million people visit agricultural fairs each year in North America.  Agricultural exhibitions provide valuable educational venues for the public. Equally important, livestock shows are an important learning opportunity for thousands of 4-H and FFA youth across the United States. For these youth, exhibiting at their county or state fair is the culmination of many months of work dedicated to the care and training of their animal.

Pigs can be infected with human, swine and avian origin influenza A viruses.  While rare, influenza A viruses can spread from pigs to people and from people to pigs. Transmission usually requires close contact between pigs and people.  This has happened in different settings, including livestock shows. When people are infected with swine origin influenza A viruses, it is termed as a variant virus infection and denoted with a “v” after the subtype (e.g. H3N2v).

In the past 5 years, cases of influenza A H1N1v, H1N2v and H3N2v have been associated with swine exhibitions.  Between 2011 and 2013, 340 human cases infected with H3N2v were reported from 13 states.  The largest outbreak occurred in 2012 when a total of 309 human cases of H3N2v flu were identified.

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Although the Public Health risk from these swine variant viruses is considered low at this time, the CDC takes these emerging swine flu viruses seriously, as evidenced by their most recent assessment.


CDC Assessment

It's possible that sporadic infections and even localized outbreaks among people with this virus will continue to occur. While there is no evidence at this time that sustained human-to-human transmission is occurring, all influenza viruses have the capacity to change and it's possible that this virus may become widespread. Illness associated with H3N2v infection so far has been mostly mild with symptoms similar to those of seasonal flu. Like seasonal flu, however, serious illness, resulting in hospitalization and death is possible. In 2012, for example, 309 infections with H3N2v were detected. Of these cases, 16 people were hospitalized and one of these people died. Most of the people who were hospitalized and the person who died had one or more health or age factor that put them at high risk of serious flu-related complications.

People at high risk of serious complications from seasonal influenza and H3N2v include children younger than 5, people with certain chronic conditions like asthma, diabetes, heart disease, weakened immune systems, pregnant women and people 65 years and older. CDC has issued guidance for people attending fairs where swine might be present this fair season, including additional precautions for people who are at high risk of serious flu complications. Limited serologic studies indicate that adults may have some pre-existing immunity to this virus while children do not. Most cases of H3N2v infection have occurred in children who have little immunity against this virus.

Hong Kong: Two Hospital Clusters Of MDR Acinetobacter Infections




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Because it is such an international city, and boasts one of the most diligent (and open) public health agencies in the world (Centre For Health Protection), Hong Kong has become a terrific  barometer for the growth of multiple drug resistant infections from around the world.


One of the toughest bacteria that hospitals must deal with is called multidrug-resistant (MDR) Acinetobacter baumannii, which in recent years has made headlines as the cause of difficult to treat wound infections among our troops serving in the Middle East.


Acinetobacter (of which there are many varieties, but A. baumannii is most often linked to human infection ) are ubiquitous in nature, and can be found in soil, water, animals and humans. A very hardy species, they can survive for extended period of time on inanimate surfaces, making them difficult to control in a health care setting (see AJIC report Hospital cleaning protocol ineffective against A. baumannii)..

And like with MRSA, many people can be colonized, but not show signs of infection.  Often very serious infections develop among those who are very ill, wounded, or immunocompromised.


Today Hong Kong’s CHP has published two reports on hospital clusters of MDR  Acinetobacter infection.


Cluster of Multi-drug Resistant Acinetobacter cases in Queen Elizabeth Hospital

The following is issued on behalf of the Hospital Authority:

The spokesperson for Queen Elizabeth Hospital (QEH) made the following announcement today (July 22):

Five male patients (aged 35 to 80) of a Ventilator Ward have been confirmed as having Multi-drug Resistant Acinetobacter (MDRA) since July 14. Two of them are infected cases and are still hospitalised at QEH. The remaining three patients were confirmed to be MDRA carriers without clinical symptoms. Out of these cases, two are still hospitalised under medical surveillance and isolation at QEH. The remaining patient has been transferred to Hong Kong Buddhist Hospital. All of the five patients are in stable condition.

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Cluster of Multi-drug Resistant Acinetobacter cases in Caritas Medical Centre

The following is issued on behalf of the Hospital Authority:

     The spokesperson of Caritas Medical Centre made the following announcement today (July 22):

Three patients (aged 37 to 88) of a male Medicine and Geriatrics Ward have been confirmed as having Multi-drug Resistant Acinetobacter (MDRA) since July 17. Two of them are infected cases. The patients are still hospitalised under medical surveillance and isolation. Two of them are in stable condition, while the other one is in serious condition.

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Just yesterday, Hong Kong reported a Case of NDM-5 Carbapenemase-producing Enterobacteriaceae under CHP investigation in a 30-year-old woman with a urinary tract infection.  


NDM-5 is a novel variant of the NDM-1 enzyme which first made headlines four years ago when  The Lancet published a study (see NDM-1: A New Acronym To Memorize)  by Walsh, Toleman, Livermore, et al.  on the emergence and growing prevalence of the antibiotic resistant enzyme on the Indian sub-continent.

While still relatively rare – at least in the United States and Europe – this growing rogues gallery of new, multi-drug resistant organisms continues to gain traction around the world, threatening an early demise for much of our current antibiotic arsenal. 


In early 2012 World Health Director-General Margaret Chan expressed a dire warning about our dwindling antibiotic arsenal (see Chan: World Faces A `Post-Antibiotic Era’) – a sentiment echoed a year later by CDC Director Thomas Frieden during the release of a major US report on the threat (see McKenna On CDC Antibiotic Resistance Report).


Dark, if not Inevitable conclusions, backed up by a long list of reports and studies showing the inexorable erosion the effectiveness of our current antibiotics to deal with rapidly evolving bacteria.   Some of these reports I’ve covered in the past include:


EID Journal: Acquisition of Drug Resistant Genes Through International Travel

AAP/CDC: New Guidance On For Antibiotics For Children

The Lancet: Antibiotic Resistance - The Need For Global Solutions

UK CMO: Antimicrobial Resistance Poses `Catastrophic Threat’

MMWR Vital Signs: Carbapenem-Resistant Enterobacteriaceae (CRE)



For a more complete look at the complex issues of antibiotic resistance, and the dearth of new drugs on the horizon, I can think of no resource better than Maryn McKenna’s superb book (and recent winner of the 2013 June Roth Memorial Book Award, American Society of Journalists and Authors) Superbug: The Fatal Menace of MRSA.

Superbug (MRSA) Book

And while I dabble in writing about the issues of antibiotic resistance, undoubtedly the best coverage can be found on Maryn’s Superbug blog.

mBio: Airborne Fragments Of MERS-CoV Detected In Saudi Camel Barn

Photo: ©FAO/Ami Vitale

Credit FAO


*** UPDATED with mBIO Link ***


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A little later today the open access journal mBio will publish a new paper, prepared by researchers from King Abdulaziz University in Saudi Arabia, on  RT-PCR testing of air samples taken from a camel barn during the time of a well studied probable camel-to-human transmission event last November (see CIDRAP: More Evidence for Camel-to-Human MERS-CoV Transmission).


mBio usually posts new articles mid-morning East Coast time every Tuesday, so I’ll update this blog with a link when they do.


Detection of the Middle East Respiratory Syndrome Coronavirus Genome in an Air Sample Originating from a Camel Barn Owned by an Infected Patient

Esam I. Azhar, Anwar M. Hashem, Sherif A. El-Kafrawy, Sayed Sartaj Sohrab, Asad S. Aburizaiza, Suha A. Farraj, Ahmed M. Hassan, Muneera S. Al-Saeed, Ghazi A. Jamjoom and Tariq A. Madani



Until that time, we’ve got a press release from the American Society for Microbiology (excerpts below). 


The discovery of fragments of MERS-COV virus in an air sample collected in a camel barn - while an important piece of the the MERS transmission puzzle - is neither totally unexpected nor proof of airborne transmission of the virus.  It only demonstrates a potential route of infection.

First the press release, then I’ll return with more.



Middle East Respiratory Syndrome coronavirus detected in the air of a Saudi Arabian camel barn

Saudi Arabian researchers have detected genetic fragments of Middle East Respiratory Syndrome coronavirus (MERS-CoV) in the air of a barn holding a camel infected with the virus. The work, published this week in mBio®, the online open-access journal of the American Society for Microbiology, indicates that further studies are needed to see if the disease can be transmitted through the air.


For the study, researchers on three consecutive days last November collected three air samples from a camel barn owned by a 43-year-old male MERS patient who lived south of the town of Jeddah, who later died from the condition. Four of the man's nine camels had shown signs of nasal discharge the week before the patient became ill; he had applied a topical medicine in the nose of one of the ill camels seven days before experiencing symptoms.

Using a laboratory technique called reverse transcription polymerase chain reaction (RT-PCR) to detect gene expression, they found that the first air sample, collected on November 7, contained genetic fragments of MERS-CoV. This was the same day that one of the patient's camels tested positive for the disease. The other samples did not test positive for MERS-CoV, suggesting short or intermittent shedding of the virus into the air surrounding the camels, said lead study author Esam Azhar, PhD, head of the Special Infectious Agents Unit at King Fahd Medical Research Center and associate professor of medical virology at King Abdulaziz University in Jeddah.

Additional experiments confirmed the presence of MERS-CoV-specific genetic sequences in the first air sample and found that these fragments were exactly identical to fragments detected in the camel and its sick owner.

"The clear message here is that detection of airborne MERS-CoV molecules, which were 100% identical with the viral genomic sequence detected from a camel actively shedding the virus in the same barn on the same day, warrants further investigations and measures to prevent possible airborne transmission of this deadly virus," Azhar said.

"This study also underscores the importance of obtaining a detailed clinical history with particular emphasis on any animal exposure for any MERS-CoV case, especially because recent reports suggest higher risk of MERS-CoV infections among people working with camels," he added.

Meanwhile, he said, mounting evidence for camel-to-human transmission of MERS-CoV warrants taking precautionary measures: People who care for camels or who work for slaughterhouses should wear face masks, gloves and protective clothing, and wash their hands frequently. It is also important to avoid contact with animals that are sick or have tested positive for MERS-CoV. Those who visit camel barns, farms or markets should wash hands before and after contact with animals. In addition, pasteurization of camel milk and proper cooking of camel meat are strongly recommended.

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Airborne (aerosolized or large droplet) transmission of MERS-CoV in humans is assumed to occur - hence the CDC’s stringent Interim Guidance for Health Professionals   on the use of PPEs – but other routes may be equally important players. 


Last May, in MERS: A Focus On Fomites?  we looked at investigations focusing on the potential  role of inanimate objects and environmental surfaces in the transmission of the virus.


How the virus jumps to man – presumably from camels – and how camels acquire, and spread the virus, is less well mapped out. As Dr. Ian Mackay graphically illustrated last may, there are a lot of options.


Camels at the centre, aerosol all around...

An airborne-centric view of how the camel could be a source of sporadic human infection by MERS-CoV, a virus that is genetically very similar whether found in camels or humans.

The inner ring (orange) is more about droplets and aerosols-if you must differentiate on size. 

These are potential routes by which a human in contact with, or near to, camels might acquire virus from them, when those camels are actively infected.

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The detection of fragments of MERS-CoV – using RT-PCR testing – in air samples in a camel barn doesn’t tell us if those fragments were viable, and capable of infecting anyone or anything. 


But this study does show that the opportunity for the virus to spread from camels through the air exists, and thus invites additional research into this plausible route of transmission.