Featured Research

from universities, journals, and other organizations

2009 H1N1 pandemic flu more damaging to lungs, opens opportunities for bacterial infection

Date:
September 19, 2011
Source:
American Society for Microbiology
Summary:
Many of the people who died from the new strain of H1N1 influenza that broke out in 2009 were suffering from another infection as well: pneumonia. A new study reveals how the two infections, pandemic influenza and pneumonia, interact to make to make a lethal combination.

Many of the people who died from the new strain of H1N1 influenza that broke out in 2009 were suffering from another infection as well: pneumonia. A new study being published Sept. 19 in the online journal mBio reveals how the two infections, pandemic influenza and pneumonia, interact to make to make a lethal combination.

Back in 2009, autopsies of 34 of the victims of the H1N1 pandemic influenza virus revealed that about half showed signs of bacterial co-infection in their lungs. This was a telling sign that the two pathogens are playing off one another, but until now little was known about the biological interactions between them or why influenza was so lethal when accompanied by pneumonia.

Using mice, Kash et al., from the National Institute of Allergy and Infectious Diseases (NIAID) and the Institute for Systems Biology (ISB), teased the problem apart. They infected some mice with the seasonal flu virus and others with the 2009 pandemic strain and waited 48 hours for the influenza to take hold. Next, they exposed some of the mice to the bacterium Streptococcus pneumoniae, one of the leading causes of pneumonia.

In mice that were only given either of the flu viruses, influenza had the same effects it has in humans, including weight loss, but all the mice infected with influenza alone survived. The mice infected with seasonal influenza and S. pneumoniae had slightly enhanced lung tissue damage, but they all survived the dual infections.

In contrast, all the mice co-infected with both the 2009 pandemic flu and S. pneumoniae showed severe weight loss and 100% mortality. The lung tissues of the dead mice revealed that the alveoli were severely inflamed and the surfaces of the bronchioles were wiped clean of the protective layer of cells called the epithelium. There was also increased bacterial replication in the lungs of the co-infected mice, a sign that the bacteria were thriving there.

Looking at the mouse genes that were expressed during infection revealed more details about how the pandemic influenza virus sets the stage for lethal bacterial infections. Mice infected with the pandemic flu virus and S. pneumoniae had a similar inflammatory response as the other mice, but they lack responses that would repair and regenerate their damaged epithelial cells, those protective tissues that would otherwise keep bacteria from penetrating to deeper layers of tissue.

All these factors add up to big problems in the lung: as compared with seasonal flu, infection with the pandemic strain of flu was associated with more extensive damage to the epithelium that requires more extensive tissue repair. This opens the body up to attack from bacterial invaders, including Streptococcus pneumoniae.

Keith Klugman, who studies pneumonia and pneumococcal disease at Emory University, edited the paper. He says the study has a number of implications for treatment of pandemic flu.

"One implication is that if you can prevent the bacterial infection, you may be able to prevent a significant fraction of the pneumonia that leads to death. There may be a role for antibiotics in the severe pneumonias that follow influenza," says Klugman.

Klugman points out that a vaccine for S. pneumoniae exists and that it is effective at interrupting transmission of pneumonia in the community. Now that we know pandemic flu causes increased susceptibility to pneumonia, says Klugman, we might head off deadly influenza-S. pneumoniae co-infections with more proactive vaccination programs.


Story Source:

The above story is based on materials provided by American Society for Microbiology. Note: Materials may be edited for content and length.


Cite This Page:

American Society for Microbiology. "2009 H1N1 pandemic flu more damaging to lungs, opens opportunities for bacterial infection." ScienceDaily. ScienceDaily, 19 September 2011. <www.sciencedaily.com/releases/2011/09/110919171333.htm>.
American Society for Microbiology. (2011, September 19). 2009 H1N1 pandemic flu more damaging to lungs, opens opportunities for bacterial infection. ScienceDaily. Retrieved September 23, 2014 from www.sciencedaily.com/releases/2011/09/110919171333.htm
American Society for Microbiology. "2009 H1N1 pandemic flu more damaging to lungs, opens opportunities for bacterial infection." ScienceDaily. www.sciencedaily.com/releases/2011/09/110919171333.htm (accessed September 23, 2014).

Share This



More Health & Medicine News

Tuesday, September 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Liberia Pleads for Help to Fight Ebola

Liberia Pleads for Help to Fight Ebola

AP (Sep. 22, 2014) Liberia's finance minister is urging the international community to quickly follow through on pledges of cash to battle Ebola. Bodies are piling up in the capital Monrovia as the nation awaits more help. (Sept. 22) Video provided by AP
Powered by NewsLook.com
Ebola Doctor Says Border Controls Critical

Ebola Doctor Says Border Controls Critical

AP (Sep. 22, 2014) A Florida doctor who helped fight the expanding Ebola outbreak in West Africa says the disease can be stopped, but only if nations quickly step up their response and make border control a priority. (Sept. 22) Video provided by AP
Powered by NewsLook.com
Global Ebola Aid Increasing But Critics Say It's Late

Global Ebola Aid Increasing But Critics Say It's Late

Newsy (Sep. 21, 2014) More than 100 tons of medical supplies were sent to West Africa on Saturday, but aid workers say the global response is still sluggish. Video provided by Newsy
Powered by NewsLook.com
Sierra Leone in Lockdown to Control Ebola

Sierra Leone in Lockdown to Control Ebola

AP (Sep. 21, 2014) Sierra Leone residents remained in lockdown on Saturday as part of a massive effort to confine millions of people to their homes in a bid to stem the biggest Ebola outbreak in history. (Sept. 20) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins