Friday, April 25, 2008

Influenza's 'round-the-world trip begins in Asia, study finds

For scientists, finding the birthplace of influenza has been like playing a long game of hide-and-go-seek. But the search seems to now be over, as a team of international researchers has shed new light on where flu originates.

A study in Science Magazine looked at influenza A H3N2 viruses, finding that since 2002, the viruses have migrated out of what the authors call the "east and southeast Asian circulation network" before making a one-way trip around the world and eventually dying off in South America. The study shows that the strains come from Asia and then arrive in Europe and North America six to nine months later. Researchers collected 13,000 samples of influenza A H3N2 virus across six continents.

So why Asia? The researchers concluded that different regions in eastern and southeastern Asia experience different rainy seasons throughout the year, which is when flu outbreaks crop up.

"There can be cities that are only 700 miles away from each other, such as Bangkok and Kuala Lumpur, which have epidemics six months apart," said Derek Smith of the University of Cambridge, the corresponding author of the study. "There is a lot of variability like this in East and Southeast Asia, so lots of opportunity for an epidemic in one country to seed an epidemic to another nearby country, like a baton passed by runners in a relay race."

Tourists and trade visitors to Asia help spread the flu throughout the world. If the trend continues, eastern and southeastern Asia may become the new focus of surveillance — which could provide improvements to future vaccines and potentially help predict changes in flu viruses.

With hide-and-go-seek now over, what we've learned can help prevent the flu's spread. Anyone for a game of tag, you're it?

Monday, April 21, 2008

Celebrate National Infant Immunization Week

Thanks to lifesaving vaccines, dreaded childhood diseases such as polio, whooping cough, mumps and measles are a distant memory for most people in the United States. But the viruses and bacteria that cause these diseases are still around and can be passed to people who have not been vaccinated.

April 19-26 marks National Infant Immunization Week, a yearly observance that emphasizes the importance of protecting the littlest members of our families from vaccine-preventable diseases. The week gives everyone a chance to celebrate all of the successes of immunization programs and works to ensure that all infants are fully immunized against 14 vaccine-preventable diseases.

This year, hundreds of communities across the United States will also join with nearly 60 other countries in the Western Hemisphere and Europe to celebrate Vaccination Week in the Americas and European Immunization Week. Every community, no matter how large or small, can help reduce and prevent vaccine-preventable diseases and celebrate National Infant Immunization Week!

The Centers for Disease Control and Prevention has resources for planning National Infant Immunization Week events, including English and Spanish-language materials, sample op-ed articles and facts. Help make more childhood infectious diseases a thing of the past!

Friday, April 18, 2008

Are you protected from measles?

With spring comes the Jewish holiday of Passover, when many Americans travel to Israel. This year, however, the Centers for Disease Control and Prevention is giving some advice to travelers: Make sure you have a measles shot so you don’t get sick!

Since September 2007, more than 900 cases of measles have been reported in Israel, with nearly 700 cases in the cities of Jerusalem and Beit Shemesh. CDC is recommending that travelers planning to go to Israel this month check their immunization status and consult with their doctor to make sure that they are vaccinated against the disease. Any travelers who become ill with a fever or other measles-like symptoms should visit a medical professional before they return to the United States. It is also good to limit any contact with other people as much as possible, because measles is very contagious and can be spread easily through coughing and sneezing.

While measles is no longer common in the United States, outbreaks still occur. Just this year, Arizona experienced nine cases of the disease, while San Diego reported 11 cases. Both outbreaks were traced to travelers who had recently spent time in Switzerland, where there was a large outbreak of measles. The travelers carried the illness back with them to the United States, leading to the rise in cases.

Don't forget to stay up to date on all of your vaccinations — not just measles — especially if you are traveling to different parts of the world where other infectious diseases are common. You never know when the next germ will sneak up on you if you're unprepared!

Photo courtesy CDC Public Health Image Library. This health marketing material was used to promote U.S. measles vaccinations during the 1960s. Before the measles vaccine became available in 1963, there were approximately 3 million to 4 million cases, and an average of 450 deaths a year in the United States, according to CDC. More than half the population had measles by the time they were 6 years old, and 90 percent had the disease by the time they were 15.

Friday, April 11, 2008

“Houston: We have contact!” (Boy, do we ever)

How many people do you come into close contact with each day? More than you may think, which may have an impact on whether you pick up the latest cold or spread it to your friends and family.

Whether it is influenza or SARS, scientists in Europe believe studying social contact patterns can be used to better understand the spread of infectious diseases, according to a study in PLoS Medicine.

To test their premise, researchers followed 7,300 European volunteers who recorded physical and other contacts for a day. The study showed that people had an average of about 13 contacts per day.

Children and teens had the greatest number of contacts, especially within their own age groups. Kids ages 5 to 9 averaged almost 15 contacts a day, while those ages 10 to 14 averaged 18 contacts, and teens ages 15 to 19 had about 17. In contrast, seniors ages 70 and older only had about seven contacts a day. Such patterns may explain why schoolchildren are coughing and sneezing so often and could have implications for kids and teens, "who are expected to suffer the highest incidence during the initial epidemic phase," the researchers wrote.

Other findings in the study showed that daily contacts or those lasting more than an hour tended to be physical. Contacts at home, school or play were more likely to be physical than contacts at the workplace or while traveling.

Researchers plan to use the study results to create mathematical models to figure out how infectious diseases can be controlled during an outbreak. But for you and me, it means that if there is an epidemic, the best plan may be to keep the family (and especially the kids and teens) at home.

Friday, April 04, 2008

National Public Health Week to connect climate change and our health

Today's entry is written by guest blogger Georges C. Benjamin, MD, FACP, FACEP (E), executive director of the American Public Health Association

What does global warming have to do with the Get Ready blog? A lot. Recent changes in our global climate have resulted in an increase of infectious disease in unexpected places.

Consider West Nile virus, which is native to Africa. The disease was first transmitted in the United States in 1999, killing seven people in New York. How did a little-known virus from a tropical climate manage to survive and thrive in the northeast United States? Scientists found that the unseasonably warm winter of 1998-1999 was followed by a long drought in the summer. Drought conditions contributed to the survival of mosquito larvae that need stagnant pools of water to thrive. These factors created a "perfect storm" for mosquitoes to transmit the West Nile virus more frequently and for a longer period of time to humans.

West Nile virus has now become established in the United States -- with 177 deaths and 4,270 cases of illness last year -- and is harbinger of what's to come as our climate shifts to warmer, more extreme weather conditions. The West Nile virus deaths are but one example of how warming conditions can impact human health.

Mosquitoes are only one form of disease transmission -- and they transmit other diseases too, including yellow fever, dengue fever, malaria and encephalitis. Severe storms caused by warmer weather result in greater runoff from sewage, fertilizers and other toxic substances. This increased runoff infects seafood and drinking water, and can lead to diseases spread through water-borne pathogens such as cholera.

Continued climate change will disrupt human life dramatically. But in no way will the impact be greater than in the cost to human health. The direct impact of severe weather is often seen immediately, in the death toll that results from hurricanes and tornadoes. However, there is a less obvious, but even more insidious toll that results from a warming climate: the suffering and deaths that result from infectious disease. In order to prevent unnecessary suffering and premature loss of life, we must begin to take what steps we can to slow climate change by reducing our greenhouse gas emissions, conserving and protecting drinking water, and recognizing the role of our consumption-based lifestyles on our own health and well-being.

Next week, April 7-13, communities across the country will celebrate National Public Health Week and help make the connection between climate change and health. Learn more about the health impacts of climate change and what steps you can take to improve your health and the health of the planet at