Corporate Banner
Satellite Banner
Immunology
Scientific Community
 
Become a Member | Sign in
Home>News>This Article
  News
Return

NIH Study Sheds Light on Role of Climate in Influenza Transmission

Published: Monday, March 11, 2013
Last Updated: Sunday, March 10, 2013
Bookmark and Share
According to new study, cold-dry and humid-rainy environmental conditions are associated with seasonal influenza epidemics.

Two types of environmental conditions - cold-dry and humid-rainy - are associated with seasonal influenza epidemics, according to an epidemiological study led by researchers at the National Institutes of Health’s Fogarty International Center.

The paper, published in PLoS Pathogens, presents a simple climate-based model that maps influenza activity globally and accounts for the diverse range of seasonal patterns observed across temperate, subtropical and tropical regions.

The findings could be used to improve existing current influenza transmission models, and could help target surveillance efforts and optimize the timing of seasonal vaccine delivery, according to Fogarty researcher Cecile Viboud, Ph.D., who headed the study.

“The model could have a broader application, encouraging researchers to analyze the association between climatic patterns and infectious disease across a wide range of diseases and latitudes,” said Viboud.

Human influenza infections exhibit a strong seasonal cycle in temperate regions, and laboratory experiments suggest that low specific humidity facilitates the airborne survival and transmission of the virus in temperate regions.

Specific humidity is the ratio of water vapor to dry air in a particular body of air while relative humidity - commonly used in weather forecasts - the amount of water vapor in the air relative to its capacity to hold water vapor, and is primarily a function of temperature.

Data from animal studies indicate low temperature and humidity increase the duration of the virus’s reproduction and expulsion in infected organisms and virus stability in the environment, increasing the probability of transmission through coughing, sneezing or breathing. In contrast, high temperature seems to block airborne transmission.

According to James Tamerius, Ph.D., a geographer at Columbia University, New York City, and the first author of the study, the effect of low specific humidity on influenza could cause annual winter epidemics in temperate areas. “However, this relationship is unlikely to account for the epidemiology of influenza in tropical and subtropical regions where epidemics often occur during the rainy season or transmit year-round without a well-defined season,” he said.

After assessing the role of local climatic variables on virus seasonality in a global sample of study sites, Viboud and her colleagues found that temperature and specific humidity were the best individual predictors of the months of maximum influenza activity, known as influenza peaks.

The team discovered that in temperate regions, influenza was more common one month after periods of minimum specific humidity. These periods happen to coincide with months of lowest temperature.

In contrast, sites that maintained high levels of specific humidity and temperature were generally characterized by influenza epidemics during the most humid and rainy months of the year. “The models we used predicted the timing of peak influenza activity with 75 to 87 percent accuracy,” said Viboud.

"Anecdotal evidence suggests that colder climates have winter flu while warmer climates that experience major fluctuations in precipitation have flu epidemics during the rainy season, and the current study fits that pattern,” said Viboud.

Viboud continued, “In contrast, the seasonality of influenza is less well-defined in locations with little variation in temperature and precipitation, and is a pattern that remains poorly understood. One hypothesis that is often used to explain tropical influenza activity is that people congregate indoors more frequently during the rainy season, increasing contact rates and disease transmission. There is little data to confirm this, however, and it’s an interesting area for future research."

To reach these conclusions, the researchers used a recently developed global database that provides information on influenza peaks from 1975-2008 for 78 sites worldwide. The study spanned a range of latitude that was between 1 and 60 degrees, with 39 percent of the sites located in the tropics.

Additionally, epidemiological data from nine countries participating in FluNet, the World Health Organization’s global influenza surveillance program, was used to ensure independent validation. The nine countries-including Spain, Tunisia, Senegal, Philippines, Vietnam, Colombia, Paraguay, South Africa and Argentina- were not represented in the original 78-location database and were chosen because each country provided several years of data.

“We’ve shown the importance of thresholds in humidity and temperature which are predictive of whether influenza activity occurs during winter months, the rainy season or throughout the year,” said Viboud. “The predictions of our climate-based models compared favorably to epidemiological information collected independently of the dataset used for the model-building exercise.”

Though the study offers researchers a new tool in the global effort to track the spread of influenza, climate is only one of several potential drivers of influenza seasonality.

“Further work should focus on examining the role of population travel and other factors in influenza transmission,” notes Mark Miller, M.D., director of Fogarty’s Division of International Epidemiology and Population Studies.”

More broadly, additional analysis of the link between climate and infectious diseases is needed- particularly for respiratory and intestinal pathogens that display marked seasonality.”

The authors conclude, “A better understanding of the environmental, demographic and social drivers of infectious disease seasonality is crucial for improving transmission models and optimizing interventions.”

The study was conducted in the context of the Multinational Influenza Seasonal Mortality Study, an ongoing international collaborative effort led by Fogarty to better understand the epidemiological and evolutionary patterns of influenza. A link to the paper can be found at http://dx.plos.org/10.1371/journal.ppat.1003194.

Fogarty, the international component of the NIH, addresses global health challenges through innovative and collaborative research and training programs and supports and advances the NIH mission through international partnerships. For more information, visit: http://www.fic.nih.gov.


Further Information

Join For Free

Access to this exclusive content is for Technology Networks Premium members only.

Join Technology Networks Premium for free access to:

  • Exclusive articles
  • Presentations from international conferences
  • Over 3,500+ scientific posters on ePosters
  • More than 5,000+ scientific videos on LabTube
  • 35 community eNewsletters


Sign In



Forgotten your details? Click Here
If you are not a member you can join here

*Please note: By logging into TechnologyNetworks.com you agree to accept the use of cookies. To find out more about the cookies we use and how to delete them, see our privacy policy.

Related Content

Oxygen Can Impair Cancer Immunotherapy
Researchers have identified a mechanism within the lungs where anticancer immune resposnse is inhibited.
Friday, August 26, 2016
New Inflammatory Disease Discovered
NIH researchers have discovered a rare and potentially deadly disease - otulipenia - the mostly affects children.
Tuesday, August 23, 2016
Oral Immunotherapy Is Safe, Effective Treatment for Peanut-Allergic Preschoolers
Study demonstrates the potential of peanut OIT to suppress allergic immune responses to peanut.
Friday, August 12, 2016
Mutations Linked to Immunotherapy Resistance
Researchers uncover mutations in tumors of three patients with advanced melanoma that allowed the tumors to become resistant to the immune checkpoint inhibitor pembrolizumab (Keytruda®).
Tuesday, August 09, 2016
Zika Vaccine Candidates Show Promise
Two experimental vaccines have shown promise against a major viral strain responsible for the Brazilian Zika outbreak.
Friday, July 29, 2016
Targeting Autoimmunity
Researchers have developed a strategy to treat a rare autoimmune disease which could lead to treatments of other autoimmune diseases.
Wednesday, July 27, 2016
NIH Investment Into HIV Research Expands
Funding has been awarded to six research teams to lead collaborative investigations worldwide toward an HIV cure.
Thursday, July 14, 2016
Drug Might Help Treat Sepsis
A DNA enzyme called Top1 plays a key role in turning on genes that cause inflammation in mouse and human cells in response to pathogens. A drug blocking this enzyme rescued mice from lethal inflammatory responses, suggesting a potential treatment for sepsis.
Wednesday, May 18, 2016
Large-scale HIV Vaccine Trial to Launch in South Africa
NIH-funded study will test safety, efficacy of vaccine regimen.
Wednesday, May 18, 2016
New HIV Vaccine Target Discovered
NIH-Led team have discovered a new vaccine target site on HIV.
Tuesday, May 17, 2016
Finding Factors That Protect Against Flu
A clinical trial examining the body’s response to seasonal flu suggests new approaches for evaluating the effectiveness of seasonal flu vaccines.
Wednesday, April 27, 2016
Factors Influencing Influenza Vaccine Effectiveness Uncovered
The long-held approach to predicting seasonal influenza vaccine effectiveness may need to be revisited, new research suggests.
Thursday, April 21, 2016
Study Finds Factors That May Influence Influenza Vaccine Effectiveness
Researchers at NIH have suggested that the long-held approach to predicting seasonal influenza vaccine effectiveness may need to be revisited.
Wednesday, April 20, 2016
Submissions Open for the Cancer Moonshot Program
NCI opens online platform to submit ideas about research for Cancer Moonshot.
Tuesday, April 19, 2016
NIH Awards Grants to Explore Vaccine Adjuvants
NIH awards six grants to explore how combination adjuvants improve vaccines.
Wednesday, April 06, 2016
Scientific News
Culex Mosquitoes Do Not Transmit Zika
A study of the Culex species mosquito appears to show that the species does not transmit Zika virus.
Bacteria Use Ranking Strategy to Fight Off Viruses
Researchers have explained why microbes store virus confrontation information sequentially, with most recent attacks first.
Molecular Switch Aids Immune Therapy
Researchers identify strategy to maximise effectiveness of immune therapy through molecular switch controlling immune suppression.
Reprogramming Lymph Nodes to Fight MS
Bioengineers work to reprogram lymph node function to fight multiple sclerosis.
Antibodies Block Norovirus’ Entrance into Cells
Scientists have uncovered a mechanism in the human body that targets and successfully blocks noroviruses.
Probe Detects Histone Modifications in Cells
Scientists have developed an antibody probe that can be used to monitor the dynamics of histone modification.
Gut Pathogens Thrive on Body's Tissue-Repair Mechanism
Researcher have discovered that harm caused by pathogens in the intestinal tract benefit from immune system response to damaged intestinal lining.
Eisai Establishes AiM Institute
The Andover innovative Medicines (AiM) Institute will develop innovative precision medicines for hard-to-treat conditions.
Antibodies that Target Holes in HIV's Defence Identified
Scientists suggest 'holes' in HIV sugar sheild can be targeted by antibodies.
Arms Race with a Superbug
Scientists have discovered that increased risk of superbug infection can be directly casued by immune system response to invading bacteria.
Skyscraper Banner

SELECTBIO Market Reports
Go to LabTube
Go to eposters
 
Access to the latest scientific news
Exclusive articles
Upload and share your posters on ePosters
Latest presentations and webinars
View a library of 1,800+ scientific and medical posters
3,500+ scientific and medical posters
A library of 2,500+ scientific videos on LabTube
5,000+ scientific videos
Close
Premium CrownJOIN TECHNOLOGY NETWORKS PREMIUM FOR FREE!