The New Normal: The Age Of Emerging Disease Threats

Photo Credit- CDC

 

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The reality of life in this second decade of the 21st century is that disease threats that once were local, can now spread globally in a matter of hours or days.  Vast oceans and prolonged travel times no longer protect us against infected travelers crossing borders. 

 

And despite the media hype over airport screening, we have no technology that can realistically, or reliably detect infected individuals and prevent them from entering a country (see  Head ‘Em Off At The Passenger Gate?).

 

As our ability to transport diseases rapidly to any corner of the globe has increased, so has the number and variety of emerging infectious diseases.  Something that was foretold two decades ago by anthropologist and researcher George Armelagos of Emory University, which I described in considerable detail in The Third Epidemiological Transition.

 

According to Dr. Armelagos, the Third Epidemiological Transition began in the late 1970s or early 1980s, and is hallmarked by newly emerging infectious diseases, re-emerging diseases carried over from the 2nd transition, and a rise in antimicrobial resistant pathogens.

 

When you combine those factors with an increasingly mobile global population of about 7 billion people, and huge increases in the number of animals being raised for food consumption (often in environments conducive to the spread of diseases), and you have a recipe for explosive growth in diseases.

 

In a 2010 paper, Armelagos along with Kristin Harper, updated his original paper.  Both papers are well worth reading.

 

Int J Environ Res Public Health. 2010 February; 7(2): 675–697.

Published online 2010 February 24. doi: 10.3390/ijerph7020675.

The Changing Disease-Scape in the Third Epidemiological Transition

Kristin Harper and George Armelagos

 

We are, quite simply, living in an age of emerging infectious diseases. 

 

Over the past three decades, dozens of new – mostly zoonotic – diseases have been identified.   Some of these new, or re-emerging disease threats, include:

 

• HIV
• SARS
• The re-emergence and spread of H5N1 bird flu in 2003
• An H1N1 `Swine Flu’  pandemic in 2009
• Swine Variant Influenza viruses (H1N1v, H1N2v, H3N2v)
• MERS-CoV and other `bat borne’ viruses like Nipah and Hendra
• H7N9, H10N8, H5N2 and other emerging avian flu viruses
• Lyme Disease, CCHF, Heartland Virus, SFTS, and other tickborne diseases
• The global spread of MRSA, along with the recent arrival of of NDM-1 and other Carbapenemases that threaten the viability of our antibiotic arsenal. 
• An explosion and spread of mosquito-borne diseases like  dengue, chikungunya & malaria
• Even old scourges, once thought on the way out, are showing new signs of life . . . like Pertussis, measles, and polio.
• Perhaps most troubling of all has been the emergence of increasingly drug resistant strains of tuberculosis.
• And the one that has everyone’s attention right now;  Ebola.

 

If you consider the toll they take each year in terms of lives lost, misery, and dollars – the most effective terrorists in this world are not humans, they are microbial.  

 

And in a lot of places around the globe, they not only have the upper hand, they are gaining territory. .

 

Yet, it wasn’t until the mid-1990s that interest in these emerging pathogens really took off. The CDC only began publishing the EID Journal, a highly respected peer-reviewed journal on emerging pathogenic threats, in 1995.   Today emerging disease threats, and neglected tropical diseases, are a hot topic in scores of respected journals.

 

Currently there is a lot of public concern over the Ebola virus, and while it is a fearsome disease, it has far less potential to wreak global havoc than many of the pathogens on the list above.   

 

Viruses that spread via respiratory routes, like MERS-CoV, the ever expanding flock of avian flu viruses, reassortant swine flu viruses, and other respiratory pathogens are all better equipped to start a global epidemic than is Ebola.

 

None of which is to suggest that Ebola isn’t a serious threat, only that if it manages to spread beyond Africa, it is more likely to manifest in the form of very small, sporadic, localized outbreaks, rather than as a global epidemic.

 

Alas, the same can not be said for many other emerging viruses, should any of them adapt well enough to humans to transmit easily.  Which is why, early this year, we looked at an assessment by the Director Of National Intelligence who includes emerging infectious diseases and  Influenza Pandemic As A National Security Threat. 

From that report:

 

Worldwide Threats Assessment – published January 29th, 2014,

(Excerpt)

Health security threats arise unpredictably from at least five sources: 

• the emergence and spread of new or reemerging microbes;
• the globalization of travel and the food supply;
• the rise of drug-resistant pathogens;
• the acceleration of biological science capabilities and the risk that these capabilities might cause inadvertent or intentional release of pathogens; and
• adversaries’ acquisition, development, and use of weaponized agents. 

Infectious diseases, whether naturally caused, intentionally produced, or accidentally released, are still among the foremost health security threats.  A more crowded and interconnected world is increasing the opportunities for human, animal, or zoonotic diseases to emerge and spread globally.  Antibiotic drug resistance is an increasing threat to global health security.  Seventy percent of known bacteria have now acquired resistance to at least one antibiotic, threatening a return to the pre-antibiotic era.

This was, admittedly, just one of many threats discussed in this 27 page threat assessment.  Others include cyber attacks, terrorism, extreme weather events, WMDs, food and water insecurity, and global economic concerns.

 

A week before that report was issued, Dr. Thomas Frieden – Director of the CDC – penned an opinion piece for CNN called How to Prevent the Next pandemic ( see CDC Director Frieden: On Preventing A Pandemic).  Many of these themes are carried forward on the CDC’s Global Health Website at:

Why Global Health Security Matters

Disease Threats Can Spread Faster and More Unpredictably Than Ever Before

(Excerpt)

A disease threat anywhere can mean a threat everywhere. It is defined by

• the emergence and spread of new microbes;
• globalization of travel and trade;
• rise of drug resistance; and
• potential use of laboratories to make and release—intentionally or not—dangerous microbes.

(Continue . . .)

 

In 2014 alone, in addition to the spread of Ebola, we’ve seen the importation of H5N1 into Canada, imported MERS-CoV cases in the United States (along with 20+ other countries), imported H7N9 to Taiwan and Hong Kong, imported CCHF in the UK, and Lassa fever in a traveler in Minneapolis, and Chikungunya has infected 500,000 people in the Caribbean over the past nine months.

 

And frankly, these are just the highlights.

 

The simple truth is, while Ebola isn’t likely to rise to the level of a global epidemic, nature’s lab is open 24/7, and it is continually producing new candidates (or refining old ones) to spark the next pandemic.  

 

Viruses like H7N9, H5N1, and H3N2v continue to mix and match genes, looking to hit the right combination to spread easily in humans.  Old influenza nemeses, to which we have limited community immunity (like H2N2) still lurk in avian populations, and upstart coronaviruses like SARS and MERS-CoV are still testing the waters, as they try to `figure us out’.

 

All of which means that if and when Ebola is contained (and I believe it will be), the greater threat won’t have gone away.  Whether the `next pandemic threat’ comes in six weeks, six months, or six years – or from what location or source - is unknowable. 

 

But few scientists would argue that another pandemic won’t emerge at some point.

 

Which is why, when the media hype and public concerns over Ebola dies down –  we should not let our resolve to strengthen public health – both here, and around the globe -  die with it. 

 

We live in an age where these threats aren’t going to go away, and we can ill afford to let our guard down.

 

For more on pandemic preparedness, you may wish to revisit:

 

The Global Reach Of Infectious Disease

HSPH Video: The Next Pandemic: Are We Ready? 

Pandemic Preparedness: Taking Our Cue From The Experts

FAO: Surge In Animal Disease Increases Zoonotic Threats

 

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According to well respected anthropologist and researcher George Armelagos of Emory University, we are entering The Third Epidemiological Transition, which began in the late 1970s or early 1980s, and is hallmarked by newly emerging infectious diseases, re-emerging diseases carried over from the 2nd transition two hundred years ago, and a rise in antimicrobial resistant pathogens.

 

Over the past three decades, dozens of new – mostly zoonotic – diseases have been identified. Some have already had a major impact on humans (e.g. HIV, Lyme, XDR-TB), while others remain marginal threats, but may have tremendous potential for greater damage in the future. 

 

Which is why we pay so much attention to avian and swine flu viruses, emerging bat coronaviruses, and vector-borne diseases like Chikungunya, Dengue, CCHF, Nipah and SFTS. 

 

With an increasingly mobile global population now numbered over 7 billion, huge increases in the number of animals being raised for food consumption (often in environments conducive to the spread of diseases), and man’s continual encroachment into remote jungles and forests of the world - you have a huge potential to introduce new `exotic’ diseases to mankind.

 

Today the FAO has released a new 130 page report that calls for new, holistic approaches in dealing with animal disease threats, and warns that humanity faces increasing threats from zoonotic diseases.

Read the report

World Livestock 2013 (.pdf version)

E-book reader version

3 minute Audio Interview with FAO Chief Veterinary Officer Juan Lubroth

 

For some more background on this report, the FAO published the following news story.

 

Surge in diseases of animal origin necessitates new approach to health - report

Focus on root causes and prevention needed

A poultry farm in Chad.

16 December 2013, Rome - Population growth, agricultural expansion, and the rise of globe-spanning food supply chains have dramatically altered how diseases emerge, jump species boundaries, and spread, according to an FAO report released today. A new, more holistic approach to managing disease threats at the animal-human-environment interface is needed, it argues.

Seventy percent of the new diseases that have emerged in humans over recent decades are of animal origin and, in part, directly related to the human quest for more animal-sourced food, according to the report, World Livestock 2013: Changing Disease Landscapes.

The ongoing expansion of agricultural lands into wild areas, coupled with a worldwide boom in livestock production, means that "livestock and wildlife are more in contact with each other, and we ourselves are more in contact with animals than ever before," said Ren Wang, FAO Assistant Director-General for Agriculture and Consumer Protection.

"What this means is that we cannot deal with human health, animal health, and ecosystem health in isolation from each other - we have to look at them together, and address the drivers of disease emergence, persistence and spread, rather than simply fighting back against diseases after they emerge," he added.

Multiple impacts of disease

FAO's new report provides a number of compelling reasons for taking a new tack on disease emergence.
Developing countries face a staggering burden of human, zoonotic and livestock diseases, it says, creating a major impediment to development and food safety. Recurrent epidemics in livestock affect food security, livelihoods, and national and local economies in poor and rich countries alike.

Meanwhile, food safety hazards and antibiotic resistance are on the increase worldwide.

Globalization and climate change are redistributing pathogens, vectors, and hosts, and pandemic risks to humans caused by pathogens of animal origin present a major concern.

(Continue . . .)

 

While the next pandemic could come from a wild bird in Asia, or the bushmeat trade out of Africa (see Bushmeat,`Wild Flavor’ & EIDs), the odds favor it coming from a commercial farm somewhere in the world where large numbers of animals intermingle, swap viruses, and come in daily contact with humans.

 

For a closer look at the risks of raising livestock, I heartily recommend Dr. Michael Greger’s free online book  Bird Flu: A Virus Of Our Own Hatching, and Helen Branswell’s terrific piece in SciAm  from late 2010 called Flu Factories.

Vast oceans and artificial geopolitical borders are no longer protection against the spread of diseases in our modern, interconnected world.

 

Which is why much more attention must be paid to global surveillance, international cooperation, and the immediate reporting of human and zoonotic disease outbreaks.

Shanghai Govt.: Thousands Of Dead Pigs Retrieved From River

   

Location Shanghai China

 

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The Huangpu river - a tributary of the Yangtze that rolls across 113 km of China’s countryside before emptying into the East China Sea – provides many of the 23 million residents of Shanghai with their drinking water.

 

This weekend, various news reports indicate that between 900 hundred and 3000 dead pigs have been retrieved from the Huangpu river - dumped for reasons, and by persons, thus far unknown.

 

A statement – machine translated – from Shanghai’s government website (www.shac.gov.cn) this morning reads:

 

Floating the Huangpu Jiang Songjiang paragraph waters the dead pigs sampling detection

The the floating dead pig incident in the Huangpu Jiang Songjiang paragraph waters, the Shanghai Animal Disease Prevention and Control Center, in conjunction with the animal epidemic control center in Songjiang District, collected at the scene a dead pig heart, liver, spleen, lung, kidney, lymph nodes, tonsils and other viscera samples 5 sets.

 

Shanghai Animal Disease Control Center laboratory using fluorescence PCR method to detect the six pathogens, including swine foot-and-mouth disease, swine fever, highly pathogenic blue ear pig disease and other major animal diseases, as well as swine pseudorabies, porcine circovirus The three kinds of pig disease, porcine epidemic diarrhea and other common disease.

 

Detection of porcine circovirus pathogen positive results from a sample, the remaining samples were negative for all test items. We will continue to trace the source, the investigation of the cause and teamed up with brothers areas and take measures to put an end to throw to the river to throw dead pig.

Note: porcine circovirus disease is caused by porcine circovirus type 2 an infectious disease of pigs, pig infectious epidemics hair a more in recent years, does not belong to the zoonoses.

 

 

The detection of porcine circovirus (PCV) type 2 among the 5 samples tested doesn’t tell us much. Not considered a zoonotic threat, PCV can be found in pigs worldwide (see University of Iowa site Porcine Circovirus Associated Diseases (PCVD, PCVAD)).

 

PCV is usually associated with a slow and progressive `wasting’ disease, casting doubt over whether it would have killed thousands of pigs simultaneously.

 

So the suspicion remains of another  – as yet unidentified – reason behind these pigs deaths.

 

CNN International this morning is reporting that a large-scale die off of pigs has been ongoing in the nearby city of Jiaxing since the first of the year. 

 

Hundreds of dead pigs fished from Shanghai river

By Katie Hunt and Zhang Dayu

(Excerpt)

A local newspaper in Jiaxing, a city in Zhejiang province south of Shanghai, reported on March 6 that tens of thousands of pigs had died of an animal disease in a major pig farming village in the past two months.

 

"According to our records, 10,078 pigs died in January, another 8,325 died in February. More than 300 pigs die everyday in our village, and we barely have any space left to dispose of the dead pigs," a local villager was quoted by the paper as saying.

 

Over the years we’ve seen other instances where diseased livestock have been dumped into rivers – an illegal disposal method that simply spreads the problem downstream (see here, here, and here).

 

During early 2009 (see The Winter Of Our Disbelief), a number of dead H5N1-infected chickens washed up on the shores of Hong Kong, which led many to believe that large numbers of chickens were being disposed of somewhere up the Pearl River in Guangdong province.

 

The following year, more infected birds turned up on the beaches and islands of Hong Kong.

 

Despite local and internet uproar, Shanghai authorities continue to assure that the city’s drinking water is safe. This assessment from the local government:

 

Shanghai Water Authority, said the requirements related to water supply enterprises to be taken to strengthen the conventional treatment process, an appropriate increase in finished water residual chlorine to 2.0 mg / l, in order to ensure the safety of the water supply. Strengthen the monitoring of the quality of raw water.

The district water departments related to tracking and monitoring of raw water quality and laboratory analysis, focusing on oxygen consumption, ammonia nitrogen, total bacterial count, total coliforms and other indicators. At present, the indicators are in the normal range.

 

And finally, from Xinhua news (the media arm of the Chinese government), we get this rather Spartan report.

 

 

Pig virus detected in Shanghai river water

2013-03-11 13:24:51

SHANGHAI, March 11 (Xinhua) -- A pig virus has been found in a water sample of a river where 1,200 dead pigs had been fished out, Shanghai authorities said.

 

Laboratory tests found porcine circovirus (PCV) in one of the water samples taken from Huangpu River, a water source for city residents, sources with Shanghai municipal agricultural commission said Monday.

 

The virus causes porcine circovirus disease in pigs but does not spread to human beings, a commission statement said.

 

All other tests of the river water provided negative results, including tests for common pig-borne diseases such as foot and mouth, swine fever, hog cholera and epidemic diarrhea.

 

Authorities are investigating where the dead pigs came from. The commission said they are working with neighboring provinces to trace their source, and have warned riverside residents to refrain from dumping animals into the river.

 

Local media reports said the pigs mainly came from Shanghai's neighboring Jiangsu and Zhejiang provinces.

 

The city and Songjiang district governments retrieved the pigs from Friday night to Sunday.

 

If and when we know more, I’ll update this story.

The 1919 Influenza Blues . . .

 

Arhoolie F-1018  Released in the 1960s Essie Jenkins et al.

 

 

# 6782

 

 

 

As it’s Friday, and some of my other interests run towards vintage audio recordings (and OTR: Old Time Radio), I was delighted to see a tweet by fellow blogger Jim Garrow ( @jgarrow & The Face of the Matter Blog) alerting his followers to a piece that appears today in Philly.com.

 

From 'TB Blues' to 'Bacteria': A musical medical history playlist

POSTED: Friday, December 14, 2012, 6:30 AM

 

You’ll find links to songs by a couple of early pioneers of American `Folk Music’ – Woody Guthrie and Jimmie Rogers – along with a  prohibition song by a lesser known, but still prolific in the 1920s & 30s, Asa Martin.

 

Essie Jenkins delivers the 1919 Influenza Blues. Regrettably, I’m unable to find much about her online.

 

Rounding out this old time playlist is a new entry, called Bacteria put together by Jonathan Coulton, cleverly using resampled audio from a KFC training video.

Disease Transmission At The Human-Animal Interface

28 page MMWR Recommendation & Report

 

# 6492

 

 

Recent headlines over the H3N2v flu virus that has jumped from pigs to a small number of humans across the Midwest have made a splash in the media, but the story is neither new, or particularly unusual.  

 

Humans in contact with animals, have always been at some risk of contracting zoonotic diseases. 

 

In a blog last year called The Third Epidemiological Transition, I described how – 100 centuries ago – mankind began to move towards a more agricultural society.  Well respected anthropologist and researcher George Armelagos of Emory University dubbed this the First Epidemiological transition.

 

We began to domesticate animals for food, using their waste as fertilizer, and created more food security than life as a nomadic hunter-gathering society could afford.

 

As we became tied to the land, families grew into villages, villages grew into towns, and towns grew into cities. But with these societal advances also came new diseases. 

 

Q Fever, Anthrax, measles and tuberculosis all gained access to human hosts from domesticated animals.  And with people clustered together in towns, and cities, these diseases were more easily spread among humans.

 

Influenza, while ubiquitous in humans today, is a disease native to waterfowl. It is unlikely that it spread very much among humans until we began to domesticate ducks and geese.

 

SARS, Ebola, bird flu, plague, Rabies, Lyme disease, West Nile, Nipah, HIV, Malaria . . . the list of diseases carried by other species - yet capable of infecting humans - is long and growing. 

 

Last June, in That Duck May Look Clean, But . . ., I wrote about a CDC investigation into an outbreak of Salmonella Montevideo involving 66 persons across 20 states linked to the handling of live poultry (baby chicks or ducklings or both) sold via mail-order hatcheries and  agricultural feed stores.

 

Similar warnings have gone out in the past regarding Human Salmonella Infections Linked to Small Turtles.  Like poultry, reptiles and amphibians can sometimes carry and spread the salmonella bacteria, which makes good hand hygiene particularly important after handling them.

 

There was an outbreak of Monkeypox – a cousin to the now eradicated small pox virus - in the United States back in 2003, after dozens of people were exposed to infected prairie dogs at a pet shop in Illinois.

 

Last March, in How Parrot Fever Changed Public Health In America, I wrote about how Chlamydophila psittaci, or `Parrot Fever’, spread across the country in 1929, sparking fears of a new pandemic.

 

And just this week (see Typhus alert issued for city of Long Beach) a California city has warned its residents about cases of flea-borne typhus, which may be carried by rodents, possums, raccoons  and cats.

 

With the recent spate of swine flu infections connected with county fairs in the Midwest, the message is going out from local health departments, and the CDC, on the importance of protecting yourself against animal borne diseases.

 

 

With the fall school session about to begin, the CDC has published advice on the safe viewing of, and contact with, animals in schools and day care centers. 

A few excerpts follow, but click the link to read the CDC’s advice in its entirety.

 

 

Animals in Schools and Daycare Settings

Animals can provide important opportunities for entertainment and learning. However, there is also a risk for getting sick or hurt from contact with animals, including those in school and daycare classrooms.

<SNIP>

What types of diseases can animals spread? Can they cause injuries?

In the United States, the biggest risk of human illnesses from animals, especially to young children, is getting infected with germs like Salmonella, E. coli O157:H7 and others that cause vomiting, diarrhea, fever, and abdominal cramping. Animals can also carry germs that cause other kinds of diseases, such as rabies. Animals may have germs on their bodies and in their droppings, even when they appear clean and healthy. The germs can also get on cages, bedding, and wherever animals roam or walk around, and can contaminate these areas.

 

Injuries caused by animals in public settings include bites, kicks, scratches, and others. Most injuries from animals can be prevented if schools and daycare classrooms follow proper safety precautions.

 

How can I reduce the risk of illness from touching or being around animals?

After you touch an animal, or anything in the areas where they live and roam, wash your hands right away to help prevent illness. Read the following tips to learn more about hand washing:

• Always wash hands right after handling animals, their food, and/or their habitats (for example, cages, water bowls, toys). Also, everyone should wash their hands after going to the toilet, before eating and drinking, before preparing food or drinks, and after removing soiled clothes or shoes.
• Adults should always supervise hand washing for young children.
• Running water and soap are best. Use hand sanitizers if running water and soap are not available. Be sure to wash your hands with soap and water as soon as a sink is available.
• Directions for washing hands can be found here.

<SNIP>

Other Animals Not Recommended in School or Child-Care Settings include:

• Inherently dangerous animals (e.g., lions, tigers, cougars, and bears).
• Nonhuman primates (e.g., monkeys and apes).
• Mammals at high risk for transmitting rabies (e.g., bats, raccoons, skunks, foxes, and coyotes).
• Aggressive or unpredictable wild or domestic animals.
• Stray animals with unknown health and vaccination history.
• Venomous or toxin-producing spiders, insects, reptiles, and amphibians.

(Continue . . . )

Read the Compendium of Measures to Prevent Disease Associated with Animals in Public Settings, 2011  [PDF - 1.33MB]

• Appendix C: Hand-Washing Recommendations to Reduce Disease Transmission from Animals in Public Settings
• Appendix D: Guidelines for Animals in School and Child-Care Settings

 

 

Whether is it raising livestock, encountering animals in the wild, or providing a good home to a beloved pet – our interactions with other species enrich our lives. 

 

But as with everything else in the world, there are some risks involved.

 

Knowing the dangers, and taking sensible steps to protect yourself from disease or injury, can help make sure these encounters remain positive ones.

PNAS: Human Networking & Infectious Disease Spread

 

# 5140

Note: Fixed broken link.

 

 

A truly ingenious piece of research, published yesterday in PNAS, that uses wireless technologies to chart the opportunities an airborne virus has to spread in a closed, heavily populated environment, like a high school.

 

The authors wired 655 students, 73 teachers, 55 staff, and 5 others with tiny remote sensors (called motes) that detected each time any of them came within 3 meters of another individual.

 

The movements, contacts (including duration), and clustering of individuals were recorded every 20 seconds over the period of a single school day in January, and during that time they collected 762,868 CPIs (Close Proximity Interactions).

 

They then ran a series of computer simulations, assigning each student (1 student at a time) as an index case with an infectious respiratory virus, and using thousands of computer runs, determined whether or not secondary transmission would occur.

 

Although no secondary transmission occurs in 2/3rds of the simulation runs - were a virus circulating in the community - multiple introductions would be expected, raising the odds of ongoing transmission.

 

The researchers also looked at the effects on transmission due to different vaccination strategies (random, students, teachers).

 

There’s a lot in this open access paper, which is admittedly heavy on math and statistics. Luckily we’ve a press release, a short audio podcast, and the abstract to give us the highlights.

 

First, the study and abstract (slightly reparagraphed for readability).

 

A high-resolution human contact network for infectious disease transmission

10.1073/pnas.1009094108

 

Marcel Salathé, Maria Kazandjieva, Jung Woo Lee, Philip Levis, Marcus W. Feldman, and James H. Jones

Abstract

The most frequent infectious diseases in humans—and those with the highest potential for rapid pandemic spread—are usually transmitted via droplets during close proximity interactions (CPIs). Despite the importance of this transmission route, very little is known about the dynamic patterns of CPIs.

 

Using wireless sensor network technology, we obtained high-resolution data of CPIs during a typical day at an American high school, permitting the reconstruction of the social network relevant for infectious disease transmission.

 

At 94% coverage, we collected 762,868 CPIs at a maximal distance of 3 m among 788 individuals. The data revealed a high-density network with typical small-world properties and a relatively homogeneous distribution of both interaction time and interaction partners among subjects.

 

Computer simulations of the spread of an influenza-like disease on the weighted contact graph are in good agreement with absentee data during the most recent influenza season. Analysis of targeted immunization strategies suggested that contact network data are required to design strategies that are significantly more effective than random immunization. Immunization strategies based on contact network data were most effective at high vaccination coverage.

 

You can listen to a brief interview with one of the authors (Marcel Salathé) HERE.

 

And a press release, from the National Science Foundation, provides the basics.

 

Human networking theory gives picture of infectious disease spread

High school students' interactions provide new look at disease transmission

It's colds and flu season, and as any parent knows, colds and flu spread like wildfire, especially through schools.

 

New research using human-networking theory may give a clearer picture of just how, exactly, infectious diseases such as the common cold, influenza, whooping cough and SARS can spread through a closed group of people, and even through populations at large.

 

With the help of 788 volunteers at a high school, Marcel Salathé, a biologist at Penn State University, developed a new technique to count the number of possible disease-spreading events that occur in a typical day.

 

This results are published in this week's issue of the journal Proceedings of the National Academy of Sciences.

 

The research was funded by the National Science Foundation (NSF) and the National Institutes of Health (NIH).

(Continue . . . )

 

 

My thanks to Carol@SC and Jane on the Flu Wiki  for the head’s up on these links.