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 3,200+ scientific posters on ePosters
  • More than 4,800+ 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

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
Experimental Vaccine Protects Against Dengue Virus
An experimental dengue vaccine protected all the volunteers who received it from infection with a live dengue virus.
Wednesday, March 30, 2016
Experimental Ebola Antibody Protects Monkeys
Antibody isolated from Ebola survivor can advance to clinical trials.
Friday, February 26, 2016
Dengue Vaccine Enters Phase 3 Trial
Investigational vaccine to prevent ‘breakbone fever’ developed at NIH.
Friday, January 15, 2016
In Uveitis, Bacteria in Gut May Instruct Immune Cells to Attack the Eye
NIH scientists propose novel mechanism to explain autoimmune uveitis.
Wednesday, August 19, 2015
Novel Mechanism to Explain Autoimmune Uveitis Proposed
A new study on mice suggests that bacteria in the gut may provide a kind of training ground for immune cells to attack the eye.
Wednesday, August 19, 2015
HIV Control Through Treatment Durably Prevents Heterosexual Transmission of Virus
NIH-funded trial proves suppressive antiretroviral therapy for HIV-infected people effective in protecting uninfected partners.
Tuesday, July 21, 2015
Scientific News
Gut Bacteria Older than Human Species
Some bacteria have lived in the human gut since before we were human, suggesting evolution could have a larger role inhuman bacterial makeup.
Evidence of Mosquito Transmitting Zika
A direct link between the Yellow fever mosquito and Zika transmission has been found following investigation into selective mosquito control.
Antibody-Based Drug for Multiple Sclerosis
New antibody-based drug paves the way for new strategies for controlling and treating multiple sclerosis.
Three-Drug Combinations Counter Antibiotic Resistance
Research shows that combinations of three different antibiotics can treat resistant bacteria, even if they are ineffective independently.
Mapping Zika’s Routes to Developing Fetus
UC researchers show how Zika virus travels from a pregnant woman to her fetus, and also identified a drug that could stop it.
Treating HIV with Cancer-Fighting Gene Shows Promise
A type of gene immunotherapy that has shown promising results against cancer could also be used against HIV.
Protein Teams Activate T-Cells
Caltech researchers have discovered T-cell genetic switching is controlled by four proteins acting in a multi-tiered fashion.
'Antigen-Presenting Cell' Defends Against Cancer
Through advanced imaging, researchers have identified cells that encourages increases in immune system cancer defences.
Zika Epidemic Likely to End Within Three Years
A team of scientists has predicted that the current Zika epidemic is likely to end within three years because there will be too few people left to infect.
Go-Between Immune Cell is Key to Priming the Body’s Fight Against Cancer
‘Antigen-presenting cell’ activates T cells by alerting them to the presence of tumors.
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
3,200+ scientific and medical posters
A library of 2,500+ scientific videos on LabTube
4,800+ scientific videos
Close
Premium CrownJOIN TECHNOLOGY NETWORKS PREMIUM FOR FREE!