June 15, 2010
UNIT 6: Classification and DiversityPandemics — Is the Next One on the Way?
Could one of these travelers be carrying a virus that causes the next pandemic?
Imagine that a new virus emerges and people have no immunity. There is no vaccine. If this were to happen, there could be mandatory travel restrictions, quarantines, and social distancing—including staying out of all crowded places. In the United States alone, such an outbreak could kill up to 2 million people. But how can such a virus emerge, and how can we prepare for it?
Pandemics
When a new virus emerges, the species that it infects has had little or no opportunity to evolve immunity. If the virus infects people, there is often little time to produce vaccines. For these reasons, a new virus may be able to spread easily from person to person.
A new virus can cause a pandemic, which is a disease outbreak that affects large areas of the world and has a high fatality rate. The 1918 flu pandemic was the most devastating pandemic recorded in world history. This virus infected nearly one-fifth of the world’s population, killing about 50 million people worldwide. It spread mainly along global trade routes and with the movement of soldiers during World War I.
If a new and deadly disease emerges today, a carrier could travel around the world in 24 hours. More than a million people travel internationally by plane every year, easily reaching their destinations before symptoms of any diseases they may be harboring appear.
The "Perfect" Virus
Not every virus is well-suited to cause massive human casualties. For many viruses, humans represent a dead-end infection because they cannot be passed from human to human. For other viruses, victims die too quickly for the virus to reproduce. Quarantines can contain this type of virus relatively easily.
What characteristics would make an emerging virus likely to cause a pandemic? The virus would need to be adapted to humans as hosts and easily spread through casual contact. Victims would also have to survive infection long enough without symptoms to go about their daily business and infect other people. Finally, the most deadly virus would mutate rapidly, foiling the attempts of scientists to develop a vaccine or a drug that targets it.
Diseases that Jump to New Species
Some diseases, called zoonoses, can jump between species. If a virus evolves the ability to jump from a nonhuman animal species to humans, our immune systems will have had little opportunity to evolve defenses. And if this virus exchanges genetic material with another human virus, a new virus that is capable of spreading from person to person may form.
Perhaps the most familiar zoonosis is the avian flu virus. Sometimes called the bird flu, this virus normally infects wild birds such as ducks and geese as well as domestic birds such as chickens. The spread of avian flu does not rely on any human form of transportation, since migrating birds can carry it to other continents.
Avian Flu H5N1
China, Thailand, Russia, Turkey, and Pakistan are among the countries that have confirmed cases of avian flu in poultry farms. Here, a Pakistani health worker vaccinates a healthy chicken.
Is avian flu the perfect killer virus? Researchers are currently tracking a form of avian flu called H5N1. Like other flu viruses, H5N1 mutates rapidly. However, mutations are random and may or may not help the virus adapt to new host species.
Unfortunately, a faster, less random way for viruses to mutate exists. Some animals can be infected with viruses from two different species at the same time. For example, if a pig becomes infected by both avian and human flu viruses at the same time, the viruses can exchange genetic information. If this happens, the avian flu can jump the species barrier, becoming a flu virus that can be transmitted from one human to another.
Unanswered Questions
Despite the danger that a new virus represents, no one knows how the virus may mutate or whether it will cause a pandemic. Some of the most important questions include the following:
- How can vaccines be developed quickly enough to stop a disease that can spread in hours or days?
- Can a broad-spectrum antiviral drug be developed that could target more than one flu virus?
- What specific molecular factors allow a virus to jump from one species to another?
UPDATES: Straight from the Headlines
- Will There Be Another Flu Pandemic Soon?
- Avian Flu: The Current Situation
- Cold Symptoms Linked to Immune Response, Not Cold Virus
- B Memory Cells Still Remember 1918 Flu Virus
- WHO Declares H1N1 Flu Virus Outbreak a Pandemic
- Researchers Find H1N1 Flu Virus Able To Infect Lung Cells
- Scientists Uncover Mystery of Flu Virus Evolution
Technology
Dissecting a Virus
Scientists have long debated how the genetic material of influenza A viruses, RNA, is likely arranged. In 2005 virologist Yoshihiro Kawaoka and his team of researchers at the University of Wisconsin unraveled the mystery using a technique called electron tomography.
Electron tomography is a way to construct a three-dimensional image from a series of electron microscope images taken at different angles. By making slices along flu virus particles that cut them into “top” and “bottom” halves, researchers found that all influenza A viruses have a total of eight RNA strands. As shown at the right, seven strands form a circle just inside the edge of the virus particle, surrounding an eighth strand in the center.
The researchers concluded that all influenza A viruses, including those responsible for regular seasonal outbreaks as well as the avian flu, must share a specific mechanism for packaging their genetic material. By knowing how these viruses package their genetic material, it may be possible to engineer viruses that can be used to mass produce vaccines.
Careers
Epidemiologist in Action
Dr. Ben Muneta
Title: Medical Epidemiologist, Indian
Health Service
Education: M.D., Stanford University
In 1993 a mystery disease began to kill people in the southwestern United States. One of the experts that the Centers for Disease Control (CDC) consulted was Dr. Ben Muneta. Dr. Muneta is an epidemiologist, a scientist who studies the causes, transmission, and control of diseases within a population. He works at the Indian Health Service National Epidemiology Program in Albuquerque, New Mexico.
Dr. Muneta consulted a traditional Navajo healer. From him, Dr. Muneta learned that the disease was associated with extra rainfall, which had caused the pinon trees to produce more nuts than usual. This in turn had led to a population explosion among mice that feed on these nuts.
Using this lead, CDC researchers determined that the disease was caused by hantavirus, a virus spread through the droppings of deer mice. With further research, Dr. Muneta confirmed that some Navajo healers had even predicted the 1993 outbreak.
Comments
Comment from: Kacey
November 18, 2008 02:23 PM [#]
pandemics are never good.....but as long as it doesn't happen anywhere close to me, it could be a new learning experience
Comment from: Wakka
September 14, 2009 02:10 PM [#]
well humans have already created viruses why cant they design a virus that tracks another virus then destroys it or renders it inactive?
Comment from: Anonymous
September 15, 2009 09:53 AM [#]
This looks great!
Comment from: lala
September 15, 2009 11:03 AM [#]
That's really interesting
Comment from: Tori
October 26, 2009 11:28 AM [#]
Now that the President has declared the H1N1 outbreak a "National Emergency" will we see additional funding for research, diagnosis, and vacinations?
Comment from: John
October 30, 2009 01:06 PM [#]
Very interesting-I saw the other day that there was H1N1 vacines being given out. There were thousands of people in line trying to get it. Like Tori said, will we see additional funding? I sure hope so because stuff like this can spread EXTREMELY fast.
Comment from: Suzanne
March 15, 2010 08:49 AM [#]
Is there any idea yet about the next flu to break out worldwide? How can I prepare myself for future outbreaks. This is information I learned has caused me to want to protect myself so I do not get the next flu to come around.
Comment from: Rylie K DNHS p. 5
June 9, 2010 10:33 AM [#]
i think its cool that scientists are already preparing for viruses that havent been created yet, and coming up with ways to cure them. i think that if scientists keep doing research we would be able to cure it, and find a vaccine for it before it even came out. i also find it fascinating that they already know a little bit about the h5n1 flu that is yet to have an impact on human life.
Comment from: justin time
August 26, 2010 12:45 PM [#]
i think its cool that scientists are already preparing for viruses that havent been created yet, and coming up with ways to cure them. i think that if scientists keep doing research we would be able to cure it, and find a vaccine for it before it even came out. i also find it fascinating that they already know a little bit about the h5n1 flu that is yet to have an impact on human life.
Comment from: Murielle
September 17, 2010 11:19 AM [#]
interesting :)
Comment from: John Lennon & Steve Irwin
March 1, 2011 09:23 AM [#]
What is H5N1? I never heard of it except for it looks like that pig flu XD But I already knew that bacteria could evolve by other bacteria so....FAIL!!!!
Comment from: Successful Girls
March 1, 2011 09:33 AM [#]
An pandemic can occur any day with all the infections so everyone should just start a healthy routine daily with sanitation to be safe of their surroundings.
Comment from: Toni
March 1, 2011 09:35 AM [#]
I think that people should get into a daily habit of sanitation. There is no reliable medications for this so people cant get the help they real need.
Comment from: Bubbles
March 1, 2011 09:35 AM [#]
i think that it is very interesting how scientist are trying to stop the viruses, by scientist doing what they can do to cure this viruses is breath taking.
Comment from: Truffels
March 1, 2011 09:35 AM [#]
It is weird how viruses can spread so rapidly if not controlled. I just hope it doesn't get to the point of everyone taking to their heels because the virus is airborne then everyone might not make it.SCARY.
Comment from: Batman
March 1, 2011 09:39 AM [#]
Its nice to know that our scientists are getting ready for any new outbreak of a virus, God forbid. But hopefully nothing to serious. Im kinda scared of the whole killer chickens thing!!
Comment from: R@KiM (a.k.a.)
March 1, 2011 09:41 AM [#]
This article taught me about how viruses can become deadly and also flu's and how animal flu's can harm humans if the human flu and animal flu exchange genetic material.
Comment from: Lil'Mermaid
March 1, 2011 09:41 AM [#]
I think that the article is very interesting. What if a new virus is out airborne? Pandemics are pretty scary. I hope all the viruses that they find now will be controlled
Comment from: NIGEL
March 1, 2011 09:43 AM [#]
From what I know H1N1 had something dealing with pigs, an the H5N1 has something dealing with chickens. I wonder will there be a virus dealing with the cow!
Comment from: Anonymous
March 1, 2011 09:46 AM [#]
It is a good idea for scientists to continue to try to cure the viruses before they occur to ensure that a pandemic will not happen.
Comment from: Sarah (SCEC)
March 1, 2011 09:48 AM [#]
The fact that viruses can trade genetic information and jump species barriers is a terrifying thought. A virus with a high mutation rate and this ability would be an extremely destructive virus.
Comment from: Aaron
March 1, 2011 09:49 AM [#]
It is scary that virus can jump the speices barrier and that if another pandemic breaks out it would be nasty.
This very informational. Thanks BioZone
Comment from: BUCCIE
March 1, 2011 09:51 AM [#]
This article is very imforative; it's amazing how much you have to worry about diseases. It's also amazing how they could expand from one person to millions of people over the period of days or even hours!!!This article makes you aware of all the things you have scientist have to worry about.
Comment from: PoLk 2012 GsW eC Ye@H bOy!~!
March 2, 2011 08:32 AM [#]
You never know when the next pandemic will occur. There are so many people in the world that viruses and pathogens are easy to be transported. Be on the alert and as always yeah boy!
Comment from: Holly
March 2, 2011 08:33 AM [#]
Its incredibly scary to think that viruses can break out to full pandemics. For instance the black plague was one of the worst in history and caused higher death rates and possible could have been the end of the human race.
Comment from: Candyland
March 2, 2011 08:35 AM [#]
This article was very informative.
Comment from: b.M.b && heavy dh'
March 2, 2011 08:37 AM [#]
It is really scary how viruses jump species barriers. The thought that a virus can spread from one person to millions of people is crazy! Reading this articles made us more alert and aware of viruses.
Comment from: his girl
March 2, 2011 08:43 AM [#]
there are so many people in the world today you never know when the next pandemic will strike.
Comment from: Brandon
March 2, 2011 08:50 AM [#]
I didn't know that viruses could mix and share characteristics. When they mutate like that, it could be hard to treat. This article was very informative.
Comment from: Jeff
August 22, 2011 11:05 PM [#]
this made me think of the black plague.
Comment from: Steven
November 8, 2011 12:07 PM [#]
Maybe in the near future, humans will be invincible to pandemics