IARC: Cell Phones `Possibly Carcinogenic’

 

 

# 5588

 

 

It was just over a year ago that the the World Health Organization’s International Agency for Research on Cancer (IARC) released their long-delayed INTERPHONE report, which was unable to establish a link between cell phone use and brain tumors (see The IARC Cell Phone Report) .

 

For a number of years some scientists have expressed concerns that prolonged exposure to cell phone RF (radiofrequency) electromagnetic fields might cause certain types of head and neck cancers.

 

And researchers worried that children, teenagers, and young adults, who rank among the most fervent users of cell phones, could be at particular risk.

 

While reassuring, the 2010 INTERPHONE report wasn’t exactly an `All Clear’ on cell phone dangers. The study, the authors admitted, had limitations. And some scientists were less than mollified by their findings.

 

At the time, Dr Christopher Wild, Director of IARC warned that additional studies were warranted.  From the IARC press release of May, 2010:

 

"An increased risk of brain cancer is not established from the data from Interphone.

 

However, observations at the highest level of cumulative call time and the changing patterns of mobile phone use since the period studied by Interphone, particularly in young people, mean that further investigation of mobile phone use and brain cancer risk is merited."

 

Earlier this year we also saw a major report in the Journal of the American Medical Association that looked at the effects of RF signal exposure on brain activity (see JAMA: Cell Phone Use Stimulates Brain Activity).

 

Using PET scans researchers were able to prove that areas of the brain in close proximity to the antennas of activated cell phones demonstrated increased glucose uptake, indicating increased localized brain activity in response to the RF (radio frequency) emissions.

 

This study indicates that the prolonged use of a cell phone does affect brain activity. What all this might mean in regards to human health remains unknown for now.

 

Fast forward to today, and the IARC has released a new statement (IARC Press Release N° 208) that lists mobile phone use in same carcinogenic hazard category as exposure to gasoline, engine exhaust and lead.

 

 

 

Given the popularity of (and our societal reliance upon) cell phones, this report – which classifies radio-frequency electromagnetic fields as possibly carcinogenic to humans (Group 2B) - is likely to spur a good deal of news coverage.

 

Group 1 carcinogens are those that are most strongly associated with cancer, like smoking and asbestos, and are considered the most dangerous.

 

Group 2a carcinogens are considered probably carcinogenic based on limited evidence of carcinogenicity in humans and sufficient evidence of carcinogenicity in experimental animals.

 

Group 2b carcinogens – where cell phones have now been ranked – are considered possibly carcinogenic, but evidence is limited in both humans and experimental animals.

 

For now, the evidence supporting a link between cell phones and certain types of brain cancer is limited. However, Dr Jonathan Samet, the overall chairman of the working group  states :

 

“ . . . the  evidence, while still accumulating, is  strong enough to support a conclusion and the 2B classification. The conclusion means that there could be some risk, and therefore we need to keep a close watch for a link between cell phones and cancer risk.” 

 

 

None of this proves that cell phones cause brain cancer.  Only that there is enough evidence to suggest a link to a specific type of cancer (glioma), and that more studies must be done.

 

Since it can take years – or even decades – for brain cancers to develop, the true health impacts from the stratospheric rise in cell phone use over the past decade may be difficult to accurately gauge for some time.

 

A full report on the IARC’s findings will be published over the next few days in The Lancet Oncology.

World No Tobacco Day

 

# 5587

 

Today, May 31st, is designated by the World Health Organization as  World No Tobacco Day.

 

This year’s focus is on WHO Framework Convention on Tobacco Control (WHO FCTC) in the fight against the global use of Tobacco.

 

Tobacco products are blamed for six million deaths each year, including hundreds of thousands due to 2nd-hand exposure.  You can read more about the WHO’s Tobacco Free Initiative including the World No Tobacco Day press release.

 

Today is also – coincidentally – the 4th anniversary of my smoking my last cigarette.

 

I was solidly hooked, smoking 2+ packs a day, and had been doing so for years.  It was expensive and disgusting habit, and was a danger to my health.

 

But all of my previous attempts to stop had failed.

I asked my doctor for advice, and he prescribed a medicine that helped me quit.  It wasn’t exactly easy . . . but it turned out not to be as difficult as I feared.

 

The point is, there are new and better ways to help you kick the habit.  Your doctor can help you find one that will work for you.

 

Believe me, if I can quit, you can too.

Google: Tracking Dengue Trends

 

 

# 5586

 

 

In November of 2008 Google – the 800 lb gorilla of Internet search engines – announced the opening of their Flu Tracking website (see Google Unveils Flu Tracking System).

 

The idea was intriguingly simple, really. 

 

Since people tend to perform internet searches on health topics of concern, it stood to reason that more people would Google `flu’ or `influenza’ when the flu was circulating in their communities.

 

By tracking the number of searches of flu-related terms by geographical region – and comparing them to baselines established over a period of years – it should be possible to get an early warning of influenza-like illness (ILI) activity.

 

The rub, of course, is that not all ILIs are the flu.

 

In October of 2009, during the height of the fall wave of the H1N1 pandemic, I posted the following graphic on my blog.

 

 

Of the more than 10,000 samples submitted for testing during the 1st week of October 2009, more than 72% – almost 3/4ths –  came back negative for influenza.

 

About a year ago a researchers at the University of Washington found that Google Flu Trends was somewhat less accurate than the CDC in predicting laboratory confirmed influenza, but was a robust tool for detecting less specific influenza-like illnesses.

 

While separating influenza from other ILIs remains a challenge, and intense media attention can spur search spikes and skew results, the data being provided by Google’s Flu Trends has proven to be both timely and valuable.

 

Since the early results from Flu Trends has proved so promising, Google is now setting their sights on the fastest growing mosquito-borne illness in the world; Dengue.

 

As with influenza-like illnesses, aggregated search totals for Dengue in a number of countries correspond closely with outbreaks. Below you’ll see the correlation between Dengue activity and Dengue-related queries in Brazil since 2003.

 

 

The Dengue Trends project is small right now, with just 5 countries being tracked (Bolivia, Brazil, India, Indonesia, and Singapore). 

 

Not all dengue-endemic countries have enough detailed historical dengue surveillance and enough Internet access and activity to monitor right now, but more countries are expected to be added over time.

 

This is what the Dengue Trends front page looks like. 

 

 

Google provides this service, and data, free of charge and as a public service. 

 

They also continue to release a number of free data mining tools, including one last week called Google Correlate that works like Google Trends in reverse.

 

Rather than inputting a search term and seeing the trend, Google Correlate allows you to upload your own data series, and see what search terms are a trending match. 

 

For more on how all of this works, check out the Google Labs announcement.  Statistical data geeks will find a White Paper on all of this, but for those of us who are arithmetically challenged, Google was kind enough to present the basics in the form of an 8-page comic book.

 

 

 

Google Flu Trends and Dengue Trends won’t supplant traditional surveillance systems, of course.

 

But they can serve as a novel and innovative real-time adjunct to conventional surveillance systems, and over time will likely improve in both geographic coverage and accuracy.

 

It should be fascinating to watch them evolve.

CMAJ: Local Acquisition Of NDM-1 In Ontario

 

 

 

 

# 5585

 

My thanks to Crof for the head’s up on this study which just appeared in the CMAJ, that looks at two cases of NDM-1 recently detected in Ontario – one of which appears to have been locally acquired.

 

NDM-1, or New Delhi metallo-ß-lactamase-1, is an  enzyme that can confer resistance to certain gram negative bacteria like E.coli and Klebsiella against a class of antibiotics called carbapenems.

 

Of particular concern, the gene (bla_NDM-1) that encodes this enzyme is carried by a plasmid – a snippet of portable DNA  - that can be horizontally transferred to other types of bacteria (see Study: Adaptation Of Plasmids To New Bacterial Species).

 

The NDM-1 enzyme made headlines last August when a Lancet Infectious Diseases article was published on its growing prevalence on the Indian sub-continent and its recent importation into the UK, US, and other countries.

 

In April of 2011, the same researchers published a new study (again in The Lancet) that found the NDM-1 enzyme in 4% of New Delhi’s sampled drinking water sources, and 30 per cent of the sewage tested (see Lancet Study: NDM-1 In New Delhi Water Supply) and perhaps most importantly – identified 11 new species of bacteria carrying the NDM-1 gene, including strains which cause cholera and dysentery.

 

While there have been scattered instances of NDM-1 bacterial infections detected in the United States and in Canada, practically all of them can be traced back to travel to India or Pakistan.

 

Today’s report in the Canadian Medical Association Journal highlights two cases of NDM-1 urinary tract colonization in Canada. In each case the patients were asymptomatic, no further spread (in-hospital or to family contacts) was detected, and antibiotics were withheld to avoid giving the bacteria an opportunity to develop further resistance.

 

One subject had recently traveled to India, while the other had not traveled outside of Ontario for at least 10 years and is believed to be the first documented instance of local acquisition of NDM-1.

 

Additionally, both cases involved bacterial strains (Morganella & Providencia) not normally associated with NDM-1, and both cases illustrate the difficulties in identifying organisms that produce NDM-1 with current laboratory testing protocols.

 

You can read the details in:

 

New Delhi metallo-ß-lactamase-1: local acquisition in Ontario, Canada, and challenges in detection

Julianne V. Kus, Manal Tadros, Andrew Simor, Donald E. Low, Allison J. McGeer, Barbara M. Willey, Cindy Larocque, Karen Pike, Iris-Ann Edwards, Helen Dedier, Roberto Melano, David A. Boyd, Michael R. Mulvey, Lisa Louie, Christopher Okeahialam, Mark Bayley, Cynthia Whitehead, Denyse Richardson, Lesley Carr, Fatema Jinnah and Susan M. Poutanen

 

 

Today’s report should not inspire undo public alarm, as the risk to the public is very low. This should, however, serve as a reminder to hospitals and health care facilities that NDM-1 is a growing concern.

 

Doctors will now have to consider that a history of recent foreign travel, while still the most common route of NDM-1 acquisition in North America, is no longer a firm prerequisite for infection.

 

And hospitals will have to gear up to deal with the the patient screening and infection control challenges that a new resistant pathogen presents, while laboratories will have to develop new testing protocols.

 

The NDM-1 enzyme was first identified in a Klebsiella pneumoniae isolate from a native of India, who was then a resident in Sweden, just three years ago. Since then it has been detected in bacteria in India, Pakistan, the United Kingdom, the United States, Canada, Japan and Brazil.

 

While the end of the antibiotic era is not yet at hand, the fear is we may be drawing closer to that day.  Which is why we watch reports of bacterial resistance with such great interest.

 

For a far more complete (and eye-opening) discussion of antimicrobial resistance issues, I can think of no better primer than Maryn McKenna’s book SUPERBUG: The Fatal Menace of MRSA.

 

And Maryn’s SUPERBUG Blog, now part of Wired Science Blogs, continues to provide the best day-to-day coverage of these issues.

AAP: Warning On Energy Drinks

 

 

# 5584

 

 

Credit- Wikipedia.

 

Over the past couple of years concerns have been raised over the consumption of so-called `energy drinks’, particularly among children and teenagers.

 

These drinks, which usually contain significant doses of caffeine and sugar, along with B vitamins, amino acids, and herbs like acai and Yerba Mate, are supposed to increase alertness and energy.

 

Some brands – which may only be legally sold to adults – contain 10%-12% alcohol.

 

Non-alcoholic versions are often used as `mixers’ for alcohol - a practice reportedly favored by college and teenage drinkers because the caffeine helps produce a `better buzz’.

 

The downside is, it can fool imbibers into believing they are sober when they are not, which can lead to even more drinking and risky behavior.

 

 

Last year these alcohol laced energy drinks came under heavy scrutiny when colleges and universities around the country began to report injuries and blackouts related to the drink's use.

 

The state of Washington banned an alcoholic energy drink called  Four Loko after nine under-aged university students (aged 17 – 19) from Central Washington University fell ill at a house party and were hospitalized. 

 

A number of colleges have recently banned these types of drinks from campus.

 

But even non-alcoholic energy beverages (EBs) have raised concerns. 

 

Excessive consumption has been linked to increased heart rates, hypertension, exacerbation of psychiatric symptoms, and very rarely - sudden cardiac death (cite - Mayo Clinic Proceedings Oct 29, 2010 :Energy Beverages: Content and Safety).

 

The Mayo report, which recommends the consumption of no more than 1 can (500ml) of EBs a day, concludes:

 

Limited ingestion of EBs by healthy people is not likely to cause major adverse effects, but binge consumption or consumption with alcohol may lead to adverse events. Individuals with medical illnesses, especially underlying heart disease, should check with their physician before using EBs, because they may exacerbate their condition.

 

Today, from the American Academy of Pediatrics, we get a stronger warning via this cautionary report on the the dangers inherent in the use of `energy & sports’ drinks by children and teenagers.  

 

The report – which is available online and for free – is called:

 

Clinical Report—Sports Drinks and Energy Drinks for Children and Adolescents: Are They Appropriate?

COMMITTEE ON NUTRITION AND THE COUNCIL ON SPORTS MEDICINE AND FITNESS

 

The `money quote’ from the abstract reads:

 

Rigorous review and analysis of the literature reveal that caffeine and other stimulant substances contained in energy drinks have no place in the diet of children and adolescents.

 

Furthermore, frequent or excessive intake of caloric sports drinks can substantially increase the risk for overweight or obesity in children and adolescents.

This report offers the following clinical guidance to pediatricians:

 

CLINICAL IMPLICATIONS: GUIDANCE FOR THE PEDIATRICIAN

Regarding consumption of sports and energy drinks by children and adolescents, the pediatrician is encouraged to:

● Improve the education of children and adolescents and their parents in the area of sports and energy drinks. This education must high-
light the difference between sports drinks and energy drinks and their associated potential
health risks.

 

● Understand that energy drinks pose potential health risks primarily because of stimulant con-
tent; therefore, they are not appropriate for children and adolescents and should never be consumed.

● Counsel that routine ingestion of carbohydrate-containing sports drinks by children and adolescents
should be avoided or restricted. Intake can lead to excessive caloric consumption and an increased risk
of overweight and obesity as well as dental erosion.

 

● Educate patients and families that sports drinks have a specific limited function for child and adolescent athletes. These drinks should be ingested when there is a need for more rapid replenishment of carbohydrates and/or electrolytes in combination with water during periods of prolonged, vigorous sports participation or other intense physical activity.

 

● Promote water, not sports or energy drinks, as the principal source of hydration for children and adolescents.

 

According to a Reuters report this weekend (Stay away from energy drinks, doctors say), the sale of non-alcoholic energy drinks will approach $9 billion dollars in the United States this year – with half of that sold to children and young adults.

 

A factoid that many parents are probably unaware of given that the use of these types of drinks appears to be a generational phenomenon. 

 

Hopefully this report, and the resultant press coverage, will serve as impetus for parents to discuss the risks of  consuming these types of beverages with their children.

The WHO’s Flu Review

 

 

# 5582

 

 

 

With the 2010-2011 northern hemisphere flu season at its end, the World Health Organization has released a summary of global influenza trends over the past six months.

 

This summary appears in the latest Weekly Epidemiological Record 2011, 86, 221–232 and on the WHO’s Global Alert and Response (GAR) page.

 

I’ve excerpted a few passages (and reformatted for readability), but the entire report is worth reading.  I’ll return with some brief comments:

 

 

 

Summary review of the 2010-2011 northern hemisphere winter influenza season

This review summarizes the chronology, epidemiology, and virology of the northern hemisphere temperate regions' winter influenza season encompassing the time period from October 2010 through the end of April 2011.

 

It is an expanded version of the WHO Weekly Epidemiological Record (WER) 27 May 2011, vol. 86 (pp 221-232).

 

Summary points

• The winter influenza season in the temperate countries of the northern hemisphere began in late October in Asia, a month later in Europe and North America, but was largely over by the end of April.

 
• The most commonly detected virus was different in North America, where influenza A(H3N2) and influenza type B co-circulated with influenza A(H1N1)2009, and Europe, where influenza A(H1N1)2009 was by far the most commonly detected virus.

• Although it was no longer the predominant influenza virus circulating in many parts of the world, H1N1 (2009) otherwise behaved much the same way as it had during the pandemic in terms of the age group most affect and the clinical pattern of illness.

• The impact of the influenza season in some areas where H1N1 (2009) was the predominant virus was more than in the previous year, most notably in the United Kingdom (UK) where intensive care units were stressed by large numbers of cases requiring ventilatory support.

• More than 90% of viruses detected around the world were similar antigenically to those found in the seasonal trivalent influenza vaccine.

 
• Antiviral resistance in influenza A(H1N1)2009 remained at a very low level. There were case reports with no history of exposure to antiviral medications, consistent with some community transmission of resistant virus.

<SNIP>

Conclusions

Influenza A(H1N1)2009 continues to circulate widely. However in contrast to the pattern observed during the pandemic, the virus is now co-circulating with other influenza viruses and was not the predominant influenza A virus in many countries.

 

Circulation this season occurred during the expected influenza seasonal time frame with no out-of-season community transmission reported in temperate northern countries. The pattern of association between severe disease and age was similar to that observed previously.

 

Influenza A(H1N1)2009 continues to be more of a problem for young and middle-aged adults, while influenza A(H3N2) causes more severe disease in adults over the age of 65 years. Influenza type B appears to disproportionately affect young children.

 

A few countries appeared to have a higher number of severe cases compared to last year for reasons that are unclear. This was most notable in the UK though this observation may well be a surveillance artefact related to the active surveillance for severe disease that was carried out there.

 

All three circulating viruses demonstrated very little antigenic drift over the last year and were closely related to the three strains contained in the seasonal influenza vaccine. In addition, all but a very small percentage of viruses tested remain sensitive to neuraminidase inhibitors.

 

This reemphasises the need to continue to vaccinate and to treat early patients at high risk for developing severe disease, including those at the extremes of age, those with certain chronic medical illness, and pregnant women.

 

 

 

While admittedly a convoluted flu season, with four flu strains (five if you count the few remnants of seasonal H1N1) in circulation, and widely varying impacts around the world – some `good news’ stands out.

 

First, the feared rise in antiviral resistance for the 2009 H1N1 virus has not yet happened, with 98% of the samples testing still sensitive to oseltamivir.

 

However, since there were a few cases of oseltamivir resistance with no known exposure to the drug, concerns over possible limited community transmission of a resistant virus remain.

 

 

Second, while scattered mutations in the 2009 H1N1 virus have been detected, the vast majority of viruses tested remain antigenically similar to the current tri-valent influenza vaccine.

 

 

The chart below illustrates 99% of the H1N1 (2009) and 96% of the  H3N2 viruses tested were antigenically similar to the current vaccine.

 

 

With two main lineages of B viruses that co-circulate each year, scientists must decide which strain to include in the vaccine. Some years they guess wrong, but this year nearly 91% of B viruses tested were a match (B Victoria) for vaccine strain.

 

 

While no guarantees can be made for what these influenza viruses will do in the next 6 to 12 months, for now they are behaving pretty much as scientists predicted.

 

The best news is that the vaccine being produced for the 2011-2012 flu season (Southern & Northern Hemisphere) appears to be an excellent match for 90% of the flu viruses currently circulating.

 

Of course, the only constant with influenza viruses is change.  

 

And so we will watch the progress of the upcoming flu season south of the equator with great interest. What happens in Australia, New Zealand, South American, and South Africa can often tell us a lot about the kind of flu season we may see in the fall.

 

Stay tuned.

EID Journal: Novel H5N5 Avian Influenza Detected In China

 

 

# 5581

 

 

 

Not that I’m trying to promote paranoia, but a recurring theme in this blog is that nature’s laboratory is open 24/7, and that it is constantly trying out new genetic combinations looking for an evolutionary advantage.

 

We see this with growing antimicrobial resistance in bacteria (see here, here, and here), emerging anti-viral resistance in influenza viruses (here and here), and even resistance in mosquitoes to DEET repellant (see From the `Nature Bats Last’ Dept).

 

If you build a better mousetrap, nature will begin work on constructing a better mouse.

 

Viruses - which generally leave behind some degree of post-infection immunity - must change over time to evade that immune response, else they would run out of susceptible hosts.  

 

Nowhere is that more apparent than in the world of influenza, where flu viruses mutate at an astonishing rate, and thus are able to spark global epidemics every year.

 

Adding to this constantly evolving pool of human influenzas are rare introductions of new, `novel’ viruses that can jump from other species (usually avian or porcine).

 

 

 

In The (Swine) Influenza Reassortment Puzzle last December, I wrote about the 19 (now 20) detected human infections by novel swine viruses in the United states.   This from the CDC report":

 

Reported Human Infections with Swine Origin Influenza Viruses (SOIV) in the United States since 2005

Of the 19 human cases reported since 2005, 12 have been trH1N1 viruses, six have been trH3N2 viruses and one has been a trH1N2 virus. All 19 persons infected with swine viruses recovered from their illness. Twelve cases occurred in children (persons younger than 19) and 7 cases occurred in adults. In 15 cases, exposure to swine has been identified.

 

The H1N1 virus that sparked the 2009 pandemic was a descendent of a triple reassorted H1N1 swine flu virus that first appeared in American swine herds in 1998.  It apparently bounced around in swine herds for a decade before finding the right genetic mutations to adapt to humans.

 

But H1N1 isn’t the only swine flu virus out there.  Known Swine influenza A viruses include H1N1, H1N2, H3N1, H3N2, and H2N3.

 

 

But for sheer diversity of influenza viruses, we look to avian species for the mother lode. 

 

Ducks, geese, and other aquatic birds are believed to be the natural reservoir – and the ultimate source – of all influenza A viruses.

 

 

While we’ve been focused on the H5N1 avian flu virus for a number of years, other avian strains (like the H7s, H9s, and H11s) have demonstrated the ability to infect humans as well.

 

Which brings us to this dispatch from the CDC’s EID Journal from the People’s Republic of China, that tells us of the discovery of a new reassortment of the avian H5 virus in domestic ducks.

 

 

Novel Reassortant Highly Pathogenic Avian Influenza (H5N5) Viruses in Domestic Ducks, China

Min Gu, Wenbo Liu, Yongzhong Cao, Daxin Peng, Xiaobo Wang, Hongquan Wan, Guo Zhao, Quangang Xu, Wei Zhang, Qingqing Song, Yanfang Li, and Xiufan Liu

Abstract

In China, domestic ducks and wild birds often share the same water, in which influenza viruses replicate preferentially. Isolation of 2 novel reassortant highly pathogenic avian influenza (H5N5) viruses from apparently healthy domestic ducks highlights the role of these ducks as reassortment vessels. Such new subtypes of influenza viruses may pose a pandemic threat.

(Continue . . . )

 

 

Undoubtedly, influenza reassortments like these happen all the time and outside the view of scientists. Most are viral flashes in the pan, are unable to compete with more biologically fit flu viruses, and so we rarely learn of them.

 

But occasionally, the right genetic combination will be generated, and a new emerging virus is born. 

 

The authors of this study write:

 

Ducks have been considered "Trojan horses" for influenza (H5N1) because of their pivotal role in virus propagation and evolution (11–13).

 

In our study, the 2 reassortant influenza viruses (008 [H5N5] and 031 [H5N5]) and their 3 possible parent viruses (108 [H5N1], 909 [H5N1], and 013 [H6N5]) were all isolated from apparently healthy domestic ducks.

 

We speculate that domestic ducks may serve as reassortant vessels for creating new subtypes of influenza viruses. In view of the practice of raising ducks in a free-range system, these novel strains could be transmitted to other domestic poultry and even humans.

 

There is evidence that these subtype H5N5 viruses have been transmitted to terrestrial poultry (Zhao et al., unpub. data). Thus, the role of domestic ducks in the influenza virus ecosystem should not be neglected.

 

Systematic surveillance should be instituted to identify emerging HPAI (H5N5) viruses and to reduce their potential threat to animal and human health.

 

Whether the H5N5 virus has evolutionary `legs’, and will ever pose a threat to poultry or humans, is unknown at this time.

 

All we really know is that it is a novel reassortment that was detected in two healthy ducks in eastern China in December 2008 and January 2009, and that it is highly pathogenic in poultry and moderately pathogenic in mice.

 

But what this does show is that without good systematic global surveillance of human, avian, and swine populations, we have no way of knowing what other emerging viruses might be fluing just under our radar.

Hurricane Preparedness Week: Day 6

 

 

# 5580

 

 

Today is day six of National Hurricane Preparedness Week, and the focus today is on preparedness.

 

 

 

One of the toughest jobs for emergency planners is to get the public to prepare for a disaster while the sun is still shining.  Until a threat looms large, most people simply don’t bother.

 

But by that time, it may be too late.

 

Essential items often disappear from store shelves in advance of a storm, and frankly, it takes time and serious thought to decide what really is important, and what isn’t.

 

Now, before a storm approaches, is the time to prepare. 

 

Craig Fugate, Director of FEMA, brings us today’s PSA on preparing for the storm.

 

 

You’ll also find a series of informative hurricane blogs on the FEMA Blog Site this week, including:

 

May 26, 2011

First there were Zombies; then came Hurricanes!

Posted by: Craig Fugate, FEMA Administrator and Ali S. Khan, Assistant Surgeon General and Director, Office of Public Health Preparedness and Response, CDC

With June 1 only days away, FEMA, CDC and the rest of the team are busy preparing for the upcoming hurricane season. And now that you’ve taken the necessary precautions to prepare for a zombie apocalypse, you can start preparing for hurricane season, too. In recognition of Hurricane Preparedness Week, we want to remind you of some simple steps you can take.  The same steps that we described in our zombie post (get a kit, make a plan, be informed) are key to getting prepared for a hurricane as well.

Get a Kit and Stock Up

(Continue . . . )

 

 

Ready.gov and the FEMA website have numerous resources available to help you and your family create, and implement, a disaster plan.

 

And NOAA joins in in reminding coastal residents, it is important to . . .

 

"Preventing the loss of life and minimizing the damage to property from hurricanes are responsibilities that are shared by all."

Throughout this Web site, information has been provided regarding actions that you can take based on specific hurricane hazards. The most important thing that you can do is to be informed and prepared. Disaster prevention includes both being prepared as well as reducing damages (mitigation).

Disaster Prevention should include:

• Developing a Family Plan
• Creating a Disaster Supply Kit
• Having a Place to Go
• Securing your Home
• Having a Pet Plan

 

 

Last March NOAA, FEMA, and the American Red Cross released an updated preparedness guide for the 2011 tropical season.

Although only 12 pages in length, this colorful PDF file packs a lot of clear, concise information on tropical storms and the threats they contain; winds, floods, surge tides, and tornadoes.

 

 

To become better prepared as an individual, family, business owner, or community to deal with hurricanes, or any other type of disaster: visit the following preparedness sites.

 

FEMA http://www.fema.gov/index.shtm

READY.GOV http://www.ready.gov/

AMERICAN RED CROSS http://www.redcross.org/

 

And lastly, you may wish to revisit some of my preparedness essays, including:

 

In An Emergency, Who Has Your Back?

An Appropriate Level Of Preparedness

PLoS: Human-Type H5N1 Receptor Binding In Egypt

 

 

# 5579

 

 

The mantra over the past five years or so on H5N1 bird flu has been that:

 

The H5N1 virus remains poorly adapted to human physiology, and despite ample opportunities in places like Egypt and Indonesia, only causes rare, sporadic infections in humans.

 

 

H5N1 is generally a gastrointestinal malady in birds, and the virus is usually spread via infected feces. The virus binds preferentially to the kind of receptor cells commonly found in avian digestive and respiratory tracts; alpha 2,3 receptor cells.

 

Human influenzas, on the other hand, are adapted to bind to the kind of receptor cells that line the surfaces of the human respiratory system; alpha 2,6 receptor cells.

 

While not an absolute, flu viruses that bind to one type of receptor cell, tend not to bind well to the other.

 

This ability to bind to a specific type of cell has often been described as the host cell being a padlock, and the virus needing a specific key (determined by the genetics of the virus’s Receptor Binding Domain: RBD) to unlock it.

 

(A Very Simplified Illustration of RBDs)

 

 

Now humans do have some avian-like alpha 2,3 receptor cells, particularly deep in the lungs.

 

This has been suggested as the reason that - when on rare occasions humans contract H5N1 - it is usually a deep lung infection.

 

It has also been postulated that H5N1’s deeper lung infections may reduce human-to-human transmission, as sneezing is a less common symptom.

 

The concern is that over time, the H5N1 (or some other avian flu) virus might mutate in such a way as to be able to bind to human α2,6 receptor cells of the upper airway.

 

And while that may not be the only obstacle keeping the virus from becoming a pandemic strain, it does appear to be a major one.

 

Although only introduced to the region in 2006, Egypt has rapidly become a hotspot for avian flu (see this list of human cases maintained on FluTrackers). 

 

Unlike some Asian countries, where the virus has proved fatal in 80% of reported cases, the CFR (Case fatality ratio) in Egypt has ranged from 10% (2009) to 34% (2010).

 

This variability in virulence has sparked concerns that important changes were taking place in the virus. 

 

Which brings us to an open access research article (excerpts slightly reformatted for readability) appearing today in PLoS Pathogens called:

 

Acquisition of Human-Type Receptor Binding Specificity by New H5N1 Influenza Virus Sublineages during Their Emergence in Birds in Egypt

Yohei Watanabe, Madiha S. Ibrahim, Hany F. Ellakany, Norihito Kawashita, Rika Mizuike, Hiroaki Hiramatsu, Nogluk Sriwilaijaroen Tatsuya Takagi, Yasuo Suzuki, Kazuyoshi Ikuta

PLoS Pathog 7(5): e1002068.

doi:10.1371/journal.ppat.1002068

AUTHOR SUMMARY

Even though highly pathogenic avian H5N1 influenza viruses lack an efficient mechanism for human-human transmission, these viruses are endemic in birds in China, Indonesia, Viet Nam and Egypt. Hotspots for bird-human transmission are indicated in areas where human cases are more than 80% of total H5N1 influenza cases.

 

Circulation among hosts may allow H5N1 virus to acquire amino acid changes enabling efficient bird-human transmission and eventually human-human transmission. The receptor specificity of viral hemagglutinin (HA) is considered a main factor affecting efficient transmissibility. Several amino acid substitutions in H5 virus HAs that increase their human-type receptor specificity have been described in virus isolates from patients, but their prevalence has been limited.

 

In contrast, we show here that new H5 sublineages in Egypt have acquired a change in receptor specificity during their diversification in birds. We found that viruses in those sublineages exhibited increased attachment and infectivity in the human lower respiratory tract, but not in the larynx.

 

Our findings may not allow a conclusion on the high pandemic potential of H5N1 virus in Egypt, but helps explain why Egypt has recently had the highest number of human H5 cases worldwide.

 

 

Since the entire research article is open access (and quite lengthy), I’ll not go into great detail on how they conducted this research here. 

 

Instead, we’ll focus on what all of this might mean.

 

While we tend to talk about the H5N1 virus as if it were a single, monolithic entity, in truth it is more akin to the mythical Hydra that is continually growing new heads.

 

The virus, as it spread from birds to other species and around the world, has evolved into a number of distinct genetic groupings called clades. As of 2009, the World Health Organization had classified the  H5N1 virus into 10 first order clades (0-9).

 

As  you can see from the chart below, while additional clades have been established over the past 10 years, the greatest diversity has been among the Clade 2 viruses.

 

 

 

Within each of these clades, the virus is continually evolving into subclades and sublineages. A few are biologically fit and manage to persist and spread, while others are not, and eventually die off.

 

Essentially H5N1 is a moving target; constantly changing, looking for an evolutionary advantage.

 

What the authors of today’s study found was that among recent human infections in Egypt, examination of viral isolates showed that several new H5 sublineages have emerged with an increased affinity for (human) α2,6 SA receptor cells while still retaining their binding ability to (avian) α2,3 SA receptor cells.

 

Using reverse genetics, they identified the the amino acid mutations that produced this new receptor binding affinity (essentially, a single mutation at HA residue 192 or a double mutation at HA residues 129 and 151).

 

They believe that the emergence of these new sublineages of H5N1 explains the increase in human cases in Egypt over the past three years.

 

Before anyone decides its time to head down to the bunker, it should be noted that this move towards greater `humanization’ of the H5N1 virus is far from complete.

 

The authors found `increased attachment and infectivity in the human lower respiratory tract, but not in the larynx.’

 

Many scientists believe the virus must learn to bind to, and replicate in, the upper airway of humans in order to transmit efficiently from human to human.

 

Something that hasn’t happened yet.

 

And there may very well be other – as yet unidentified -genetic changes that must occur before the virus can acquire human pandemic capability.

 

Something that could take years or even decades to evolve. Or admittedly, might never happen.

 

But today’s study is a not-so-gentle reminder that the H5N1 virus has not gone away, that it continues to try out new evolutionary tricks, and that it could still some day pose a pandemic threat to humanity.

 

Which is why the world remains at Pre-pandemic Phase III for the H5N1 virus.

 

Grady Norton: A Hurricane Forecasting Legend

 

 

Note: Today is day five of  National Hurricane Preparedness Week, and the focus today is on forecasting.

 

With that in mind, I’ve a look at how the technology has changed over the past 50 years and a profile of hurricane forecasting legend Grady Norton.

 

# 5578

 

 

For those of a certain age, who can remember growing up along the Gulf or Atlantic coasts in the 1950’s - before the advent of weather satellites - the technology we have at hand today is truly remarkable.

 

Our satellites today can probe deep into storm clouds and detect wind speeds, water vapor, precipitation, and heat energy of storm systems a thousand miles from the nearest weather observation post.

 

Three different views from space, taken May 26th, 2011 1345Z – NOAA 

 

Weather forecasting began a new age when on April 1st 1960,  Tiros I - the world's first weather satellite - was launched into Earth orbit from Cape Canaveral, Florida.

 

For the first time, we had a `god's eye view' of earth. Regions of our globe where once cartographers could only inscribe "Here there be Dragons' could be watched 24 hours a day.

 

Our view of our world changed, practically overnight.

 

It was a wondrous day for everyone, except possibly for members of the Flat Earth Society. Below is the first television picture from earth orbit.

 

I was six years old, and I remember it like it was yesterday.

 

 

Sure the pictures were grainy, and the resolution laughable by today's standards, but for the first time we could watch from aloft and observe how and where hurricanes formed.

 

It meant we were no longer solely dependent on ship's reports and Hurricane Hunter aircraft to know if disaster lay just beyond the horizon.

It meant more than 12 hours warning to prepare for a storm.

 

TIROS 1 could take and transmit about 1 picture an hour, and only during daylight hours. Infrared capability – which allowed 24 hour coverage - was added to later `birds'.

 

Today, our reconnaissance satellites can take 40 pictures an hour, and see right through the clouds and measure rainfall, winds and even sea water temperatures. As a result, hurricane forecasting has improved tremendously over the past 50 years.

For those with an interest in how it was done before the advent of weather satellites and supercomputers, I’ve a bit of a treat today.

 

A profile of the first great hurricane forecaster – Grady Norton.

 

First, during the 1950’s there was a little remembered TV series called The Man Behind The Badge.  Hosted by Charles Bickford, the show profiled public servants who had made important contributions to public safety.

 

In 1955 a dramatized tribute to legendary hurricane forecaster Grady Norton was broadcast.  Grady had passed away suddenly of a stroke just a few months before while tracking Hurricane Hazel.  

 

October 10th, 1954 Daytona News-Journal Article.

 

This 30 minute show stars Milburn Stone (of Gunsmoke Fame), and is hosted by a nostalgia TV site called LIKE Television.   It’s a fictionalized story, but I think you’ll find it well worth viewing.

 

Click the image below to view the show.

I

 

 

Norton became the Chief Hurricane Forecaster at the Jacksonville Weather Bureau Hurricane center in 1935 and famously forecast the track of the 200+ MPH Labor Day storm that year, providing 12 critical hours of warning to the Keys and South Florida.  

 

 

 

In 1943 the Hurricane forecasting office moved to Miami, as a joint effort of the National Weather Service, Air Force, and Navy.  Norton remained their Chief forecaster and most public spokesperson until his death in 1954.

 

It wasn’t until the mid-1960s that the NHC as we know it today was established as its own entity, separate from the National Weather Service.

 

While  the first director of the National Hurricane Center is listed as Gordon Dunn (1965–1967), Grady Norton is widely regarded as that agency’s first `unofficial’ director.

 

When meteorologists talk about Grady Norton today, they do so with considerable wonder and awe. His uncanny ability to track storms based on little more than ships reports was the stuff of legend.

 

While primitive by today’s standards, the work done by Grady Norton and other pioneers of meteorology during the first half of the last century deserves mention and remembrance. 

 

Despite the limited technology of the day, they undoubtedly saved a lot of lives.

Cucumbers Linked To German E. Coli Outbreak

 

 

# 5577

 

The severe outbreak of E. coli in Germany – which as reportedly killed 4 people and sickened hundreds (see E. Coli & Hemolytic Uremic Syndrome In Germany) - has apparently been traced to cucumbers.

 

Three of four contaminated cucumbers analyzed by the Hamburg Institute for Hygiene and the Environment came from Spain, while the fourth was described as `organic’ but without a specified place of origin.

 

 

This report from Reuters.

 

Germans pin E. coli outbreak on Spanish cucumbers

HAMBURG | Thu May 26, 2011 8:57am EDT

HAMBURG May 26 (Reuters) - German health officials identified imported cucumbers from Spain on Thursday as the source of a two-week E. coli outbreak that has killed at least four people and made more than 100 others ill.

(Continue . . . )

 

 

While this may help solve the mystery as to how this virulent form of E. coli ended up in the food chain, with more than 100 people hospitalized and seriously ill with HUS (Hemolytic Uremic Syndrome), this story is far from over.

 

Genetic analysis of this rare VTEC (Verotoxin Producing Escherichia coli) continue.

You Say You Want An Evolution?

 

 

 

# 5576

 

 

One of the topics we return to in this blog with some frequency is the potential for pigs – which are susceptible to a variety of swine, human, and avian influenza viruses - to serve as `mixing vessels’ and to generate new influenza strains.

 

Since pigs can be infected by more than one flu virus at the same time, the potential exists for two viruses to swap genetic material (reassort), resulting in a new hybrid strain.

 

The pandemic virus that emerged in the spring of 2009 was the end product of several influenza strains that had kicked around the world’s swine population for many years, trading bits of genetic material back and forth, until they produced a version capable of jumping to humans.

 

In the not-too-distant past, pigs were usually raised and slaughtered locally.

 

Over the past couple of decades, however, the cross country - and even international – shipping of live hogs has become a big business.  

 

According to Dr. Michael Greger’s excellent Flu Factories video presentation, pigs raised in the United States often travel hundreds of miles `on the hoof’, with many being `bred in North Carolina,  fattened in the corn belt of Iowa, but slaughtered in California’.

 

Which means that a swine virus that emerges in North Carolina could easily spread across the nation, carried either by live pigs, or on contaminated transport vehicles.

 

Internationally, live hogs are often shipped for breeding purposes, to inject genetic diversity into local herds to improve the breed.

 

Unfortunately, this practice has also increased viral diversity as well, introducing North American and European flu stains to places like China.

 

All of which serves as prelude to a study which was published yesterday in the Journal Nature, that takes the most extensive look to date at the introduction and evolution of swine flu viruses in China over the past 12 years (supplemented by data going back 34 years).

 

This report has an impressive pedigree, including such familiar names in the world of influenza virology as Kennedy F. Shortridge, Richard J. Webby, Robert G. Webster, Yi Guan  and  J. S. Malik Peiris.

 

 

Long-term evolution and transmission dynamics of swine influenza A virus

Dhanasekaran Vijaykrishna,Gavin J. D. Smith, Oliver G. Pybus, Huachen Zhu, Samir Bhatt, Leo L. M. Poon, Steven Riley, Justin Bahl, Siu K. Ma, Chung L. Cheung, Ranawaka A. P. M. Perera, Honglin Chen, Kennedy F. Shortridge, Richard J. Webby, Robert G. Webster, Yi Guan & J. S. Malik Peiris

 

 

Although the study is, lamentably, not open access, we’ve a number of resources giving us overviews of what was found.

 

First stop is a press release from the NIH/NIAID, which partially funded this work.

 

Evolution of swine flu viruses traced in long-term study

NIH-funded project yields baseline for better understanding of human influenza

Although swine influenza viruses usually sicken only pigs, potentially one might also spark a pandemic in people, as occurred with the 2009 H1N1 influenza virus. Because few long-term studies have surveyed flu viruses in swine, however, gaps exist in what is known about the evolution of swine influenza viruses and the conditions that enable a swine virus to infect humans and cause disease.

 

In new research reported in Nature, scientists analyzed the genetic makeup of more than 650 influenza viruses isolated during the systematic surveillance of pigs slaughtered in Hong Kong between 1998 and 2010. When the investigators supplemented this information with additional data stretching back 34 years, they could discern when specific subtypes of flu virus—including strains that had previously infected only birds or humans—first appeared in Hong Kong swine.

 

The researchers also traced the relative abundance of each of three major swine influenza virus lineages: classical, Eurasian avian-like and triple reassortant. Examples of all three of these long-established virus family lineages were found in varying proportions in samples gathered between 2002 and 2009. Before 2003, the classical lineage predominated; by 2005, the Eurasian lineage, first detected in 2001, had become most common. The most recent samples contain not only viruses from the three previously established swine lineages, but also from the new 2009 H1N1 strain. It is not yet known whether the new pandemic strain will permanently establish itself in swine.

 

According to this analysis, the three swine influenza virus lineages have crossed geographic boundaries, including continents. Such extensive co-circulation of multiple strains facilitates gene-swapping between viruses, note the researchers, and they recommend continued surveillance of swine influenza genetic diversity to better understand how this process might give rise to variants with the potential to cause human flu epidemics. Their baseline data not only show the evolutionary dynamics in swine influenza, but also highlight ways in which swine flu viruses might most readily adapt to cause infection in people.

 

CIDRAP , as part of their daily news scan, has a brief report on this as well (excerpted, and slightly reformatted for readability).

 

Imports helped swine flu in Hong Kong pigs to diversify

Importing pigs from Europe and North America over the past 30 years appears to have increased the genetic diversity of swine influenza in Hong Kong pigs through gene reassortment, according to a study today in Nature.

 

<SNIP>

 

The authors write, "Intercontinental virus movement has led to reassortment and lineage replacement, creating an antigenically and genetically diverse virus population."

 

Vijaykrishna Dhanasekaran, PhD, of Duke University, a study co-author, said the increased genetic diversity "means that the repertoire of viruses that humans are in contact with every day has increased, and this may lead to a higher likelihood of swine-to-human transmission, although the risk remains unquantified."

 

 

Duke University Medical Center – a participant in this study – has also put out a press release.

 

 

Long-term study of swine flu viruses shows increasing viral diversity

DURHAM, NC and SINGAPORE – Increased transportation of live pigs appears to have driven an increase in the diversity of swine influenza viruses found in the animals in Hong Kong over the last three decades, according to a new study.

 

In the longest study of its kind, Duke-NUS Graduate Medical School researchers found that swine viruses crossed geographic borders and mixed with local viruses, increasing their diversity.

 

(Continue . . . )

 

 

While this data is both vital and welcome, for most of the developing world, little or no viral surveillance of pigs takes place.

 

Even in the U.S. some hog farmers are reluctant to allow their herds to be tested (see Swine Flu: Don’t Test, Don’t Tell) out of fears that the discovery of a new swine flu virus would depress pork sales.

 

Some will only consent to anonymous testing, which limits the CDC’s ability to investigate cases.

 

Every once in awhile we get a report from somewhere in the world that a human has been infected with a novel influenza virus, usually of swine, avian - or quite often - mixed origin.  A few examples:

 

China: Single Novel Swine Flu Infection Reported

North America Influenza Surveillance - Week 4

CDC: Another Novel H3N2 Isolate

 

Rarely, as in the case of the 2009 swine flu virus, a novel strain adapts well enough to humans to spread efficiently through the population.

 

Most of the time, however, these are one-off type infections that are directly transmitted from an animal (pig, bird) to a single human.  Secondary transmission of the virus to others probably occurs, but only rarely and in a limited fashion.

 

But this serves as a constant reminder that nature’s laboratory is open 24/7, and viral evolution proceeds at remarkable speed.

 

For more background on influenza in swine, and the risks of reassortment, you can’t do better than  Helen Branswell’s excellent Scientific American article from last December called Flu Factories, or her SciAm Podcast.

 

You may also wish to revisit.

 

Hong Kong: Influenza Surveillance In Pigs

EID Journal: Swine Flu Reassortants In Pigs

The (Swine) Influenza Reassortment Puzzle

If You’ve Seen One Triple Reassortant Swine Flu Virus . . .

Hurricane Preparedness Week: Inland Flooding

 

 

# 5575

 

 

 

Today is day four of  National Hurricane Preparedness Week, and the focus today is on inland flooding. 

 

 

Although we automatically think of high winds and surge tides as the most immediate threats from hurricanes, slow moving tropical systems can dump 1 to 2 feet of rain on an area – often hundreds of miles inland – in a matter of a day or two.

 

On Sunday, I listed some of the major inland flooding events caused by hurricanes in my blog National Hurricane Preparedness Week 2011.

Here is today’s NHC public service announcement video.

 

 

From NOAA’s Inland Flooding page:

 

What can you do?

• When you hear hurricane, think inland flooding.
• Determine whether you live in a potential flood zone.
• If advised to evacuate, do so immediately.
• Keep abreast of road conditions through the news media.
• Move to a safe area before access is cut off by flood water.
• Do not attempt to cross flowing water. As little as six inches of water may cause you to lose control of your vehicle.
• Develop a flood emergency action plan.
• Have flood insurance. Flood damage is not usually covered by homeowners insurance.  Do not make assumptions.  Check your policy.

 

You don’t have to live on, or even near, the coast to be affected by a tropical system, as you can see by the tracks of some notable storms described on the National Hurricane Center’s Tropical History page.

 

 

 

 

Hurricane Week continues through Saturday.  

 

Now . .  before the tropics heat up, is the time to make your preparations for this year’s season.

Tornado Threat Moves East

 

 

# 5574

 

 

In the past hour NOAA's  Storm Prediction Center in Norman, Oklahoma has upgraded today’s severe weather threat from moderate to HIGH, and has designated the highest risk area east to be parts of the lower-Mississippi, mid-Mississippi, and lower-Ohio valleys later today.

 

NIH: School Closings Effective In 2009 Pandemic

 

 

 

# 5573

 

One of the most contentious issues during the opening days and weeks of the 2009 novel H1N1 outbreak was the wisdom of closing schools to reduce transmission of the virus.

 

Since the virulence of the virus was largely unknown during those opening weeks, school closures were recommended by the CDC, and by other public health entities around the world.  

 

The closing of schools, and other venues where people gather (sporting events, restaurants, shopping malls), has long been argued as being potentially an important mitigation strategy during a pandemic.

 

By early May (2009), however, it was apparent that the severity of this particular influenza virus was less than originally feared, and many public health agencies moderated their recommendations  (see CDC No Longer Recommending School Closures For A/H1N1).

 

Some school districts, in the U.S., and elsewhere around the world, continued to close schools on a case-by-case basis well into the fall of 2009.

 

In a future, more severe pandemic, the extended closing of schools will once again likely be considered to help reduce the spread of the virus.

 

It isn’t an easy decision, however.  School closings are controversial, and the issues are complex  (see The Debate Over School Closures).

 

Critics point out that working parents rely on schools to watch their kids for much of the year during the day, and many low income families benefit from the school lunch program.

 

And of course, when schools are closed during a pandemic, some kids may congregate elsewhere and spread the virus anyway.

 

 

It is important, therefore, to get some idea of the benefits that school closings would generate. To that end we’ve seen several studies over the past two years that have produced varying estimates.

 

Study: Pandemic Mitigation by Early School Closure

Study: Student Behavior During Pandemic School Closings

School Closures Revisited

Study: Effect Of School Closures On Viral Transmission

Today we’ve a new study by the NIH’s Fogarty International Center, Arizona State University and colleagues at the Mexican Institute for Social Security that appears in PLoS Medicine that looks at the epidemiology of the H1N1 outbreak in Mexico, and the effects of school closings and social distancing on its transmission.

 

Our first stop are a few excerpts (slightly reformatted) from NIH press release, which summarizes this research article nicely.

 

 

Embargoed for Release
Tuesday, May 24, 2011
5 p.m. EDT

Mexican flu pandemic study supports social distancing

Fogarty research published in PLoS Medicine

Eighteen-day periods of mandatory school closures and other social distancing measures were associated with a 29 to 37 percent reduction in influenza transmission rates in Mexico during the 2009 pandemic. The research was carried out by scientists at the Fogarty International Center at the National Institutes of Health and published in PLoS Medicine.

 

The social distancing measures implemented by the Mexican health authorities in spring 2009 were effective in reducing disease transmission by more than one-third, the study found.

 

Social distancing interventions can be implemented during unusual infectious diseases outbreaks and include school closing, closure of movie theaters and restaurants, and the cancellation of large public gatherings. Mexico implemented a nationwide mandatory school closure policy during an 18-day period in late April and early May 2011.

 

The United States implemented school closure interventions on a local basis during the 2009 pandemic, but the impact of these interventions has yet to be evaluated.

(Continue . . .)

 

 

During a particularly severe pandemic, it has been suggested that schools could be closed for up to 12 weeks. While drastic, that strategy is based – in part – on some of the experiences from the last great pandemic in 1918.

 

 

The chart above, taken from the PNAS journal article entitled Public Health Interventions and Pandemic Intensity During the 1918 Influenza Pandemic , shows the excess mortality in two American cities.

 

The tall spike represents Philadelphia, while the lower curve represents St. Louis.

 

Many researchers believe the startling difference in attack rates, and mortality, in these two cities can be explained by the way each city dealt with the outbreak.

 

In St. Louis, the Health Department closed public venues such as schools, theatres and churches very early in the outbreak, while Philadelphia did not.

 

While are societal costs to closing schools and other public venues, studies continue to show that during a severe pandemic it might very well be worth doing. 

 

Here are some excerpts from the open access article in Plos Medicine.  Follow the link to read it in its entirety.

 

 

 

Characterizing the Epidemiology of the 2009 Influenza A/H1N1 Pandemic in Mexico

Gerardo Chowell, Santiago Echevarría-Zuno Cécile Viboud, Lone Simonsen, James Tamerius, Mark A. Miller, Víctor H. Borja-Aburto

Abstract  (Excerpts)

Background

Mexico's local and national authorities initiated an intense public health response during the early stages of the 2009 A/H1N1 pandemic. In this study we analyzed the epidemiological patterns of the pandemic during April–December 2009 in Mexico and evaluated the impact of nonmedical interventions, school cycles, and demographic factors on influenza transmission.

 

Methods and Findings

. . .   We estimate that the 18-day period of mandatory school closures and other social distancing measures implemented in the greater Mexico City area was associated with a 29%–37% reduction in influenza transmission in spring 2009. In addition, an increase in R was observed in late May and early June in the southeast states, after mandatory school suspension resumed and before summer vacation started. State-specific fall pandemic waves began 2–5 weeks after school reopened for the fall term, coinciding with an age shift in influenza cases.

Conclusions

We documented three spatially heterogeneous waves of the 2009 A/H1N1 pandemic virus in Mexico, which were characterized by a relatively young age distribution of cases. Our study highlights the importance of school cycles on the transmission dynamics of this pandemic influenza strain and suggests that school closure and other mitigation measures could be useful to mitigate future influenza pandemics.