(Press-News.org) A parent's wise advice to never go to a hospital unless you want to get sick may be gaining support from scientific studies on a specific airborne virus.
The results of a Virginia Tech study by environmental engineers and a virologist on the risk of airborne infection in public places from concentrations of influenza A viruses is appearing today in the on-line, Feb. 2 issue of the United Kingdom's Journal of the Royal Society Interface.
Linsey Marr, associate professor of civil and environmental engineering at Virginia Tech, http://www.cee.vt.edu/people/lmarr.html and her colleagues, Wan Yang, of Blacksburg, Va., one of her graduate students, and Elankumaran Subbiah, a virologist in the biomedical sciences and pathobiology department of the Virginia-Maryland Regional College of Veterinary Medicine, http://www.vetmed.vt.edu/org/dbsp/faculty/subbiah.asp conducted their research in a health center, a daycare facility, and onboard airplanes.
"The relative importance of the airborne route in influenza transmission—in which tiny respiratory droplets from infected individuals are inhaled by others—is not known," Marr, who received a National Science Foundation CAREER Award to pinpoint sources of unhealthy air pollutants, said.
What is known is that influenza A viruses are "transmitted through direct contact, indirect contact, large respiratory droplets, and aerosols that are left behind by the evaporation of larger droplets," they reported in the journal. "The aerosol transmission route is particularly controversial since there is scant proof of infection mediated by virus-laden aerosols, partly due to the difficulties in studies involving human subjects and partly due to the challenges in detecting influenza A viruses in ambient air."
What happens is an infected person might cough or sneeze or just be engaged in conversation, and release the viruses into the air. However, these aerosols are quickly diluted to very low concentrations by the surrounding air.
Marr said, "Few studies have measured actual concentrations of influenza A viruses in air and determined the size of influenza-laden particles. Size is important because it determines how long the particles will remain suspended in the air before being removed due to the forces of gravity or other processes."
To conduct their studies, the Virginia Tech researchers collected samples from a waiting room of a health care center, two toddlers' rooms and one babies' area of a daycare center, as well as three cross-country flights between Roanoke, Va., and San Francisco, Ca. They collected 16 samples between Dec. 10, 2009 and Apr. 22, 2010.
"Half of the samples were confirmed to contain aerosolized influenza A viruses," Marr said. "In the others, it is possible that no infected individuals were present."
Marr added, "The average concentration was 16,000 viruses per cubic meter of
air, and the majority of the viruses were associated with fine particles, less than 2.5 micrometers, which can remain suspended for hours. Given these concentrations, the amount of viruses a person would inhale over one hour would be adequate to induce infection."
Subbiah indicated that most studies of airborne transmission of influenza viruses in animals examined the ability of infected animals to transmit the infection to susceptible in-contact animals. How the ambient environment affects the virus after release from the infected host until it reaches the recipient host is relatively unknown. Results of the study show that under defined conditions of humidity and temperature, viruses may remain suspended in air.
Incorporating the concentrations of influenza A viruses and breathing rates, Marr and her colleagues estimated the inhalation dose incurred by someone in the same room and concluded that it was sufficient to induce infection.
"As a whole," the three authors concluded in the Journal of the Royal Society Interface, "our results provide quantitative support for the possibility of airborne transmission of influenza in indoor environments."
INFORMATION:
Size of airborne flu virus impacts risk, Virginia Tech researchers say
2011-02-02
[Attachments] See images for this press release:
ELSE PRESS RELEASES FROM THIS DATE:
1 donor cornea, 2 patients helped
2011-02-02
SAN FRANCISCO–German researcher Claus Cursiefen, MD, also affiliated with Harvard School of Medicine, reports good results with a new surgical strategy that uses a single donor cornea to help two patients with differing corneal diseases. In the United States keeping pace with demand for donated corneal tissue for use in transplant surgery is a cause for concern, while in Europe and Asia shortages lead to treatment delays. Dr. Cursiefen's new approach restored good vision to patients who had Fuchs' dystrophy (degeneration of certain corneal cells) or keratoconus (thin, cone-shaped ...
Maternal stroke history tied to women's heart attack risk
2011-02-02
If you're a woman and your mother had a stroke, you may have a risk of heart attack in addition to a higher risk of stroke, according to new research on family history and heart disease published in the American Heart Association journal Circulation: Cardiovascular Genetics.
In a study of more than 2,200 patients, female heart patients were more likely to have mothers who had suffered a stroke than fathers who did.
"Our study results point towards sex-specific heritability of vascular disease across different arterial territories — namely coronary and cerebral artery ...
For-profit hospice patients more likely to require lower skilled-care needs, longer lengths of stay
2011-02-02
An examination of data from a nationally representative sample of patients discharged from hospices demonstrated that compared with nonprofit hospice agencies, for-profit hospices had a higher percentage of patients with diagnoses associated with lower skilled-care needs (such as dementia) and longer lengths of stay, according to a study in the February 2 issue of JAMA.
During the past 10 years, the for-profit hospice sector has increased substantially, with a doubling of these types of hospices from 2000 to 2007, while the number of nonprofit hospices has remained essentially ...
Sleep selectively stores useful memories
2011-02-02
After a good night's sleep, people remember information better when they know it will be useful in the future, according to a new study in the Feb. 2 issue of The Journal of Neuroscience. The findings suggest that the brain evaluates memories during sleep and preferentially retains the ones that are most relevant.
Humans take in large amounts of information every day. Most is encoded into memories by the brain and initially stored, but the majority of information is quickly forgotten. In this study, a team of researchers led by Jan Born, PhD, of the University of ...
Cancer drug used in combination with other therapies associated with increased risk of death
2011-02-02
An analysis of previous studies indicates that compared with chemotherapy alone, use of the cancer drug bevacizumab in combination with chemotherapy or biological therapy is associated with an increased risk of treatment-related death, according to an article in the February 2 issue of JAMA.
A fatal adverse event (FAE) is defined as a death caused in all likelihood by a drug and is a major cause of fatality in the United States. Bevacizumab was approved in combination with chemotherapy for treating many types of advanced cancer, including colorectal cancer, non-small ...
Wide variation exists in receipt of recommended medications for Medicare managed care RA patients
2011-02-02
An analysis of data from more than 90,000 Medicare managed care enrollees who received care for rheumatoid arthritis finds that more than one-third did not receive the recommended treatment with a disease-modifying antirheumatic drug, and that receipt varied by demographic factors, socioeconomic status, geographic location and health plan, according to a study in the February 2 issue of JAMA.
Despite evidence-based guidelines recommending early and aggressive treatment of active rheumatoid arthritis (RA), recent population-based studies of disease-modifying antirheumatic ...
In tiny fruit flies, researchers identify metabolic 'switch' that links normal growth to cancer
2011-02-02
SALT LAKE CITY—As day-old embryos, fruit flies called Drosophila enter a stage in which their cells freely divide and proliferate as the insect grows dramatically in size.
This is true for all animals, which undergo most of their growth prior to sexual maturation. Until now, researchers have known nothing about the metabolic state that occurs when cells divide during early development. But in a study published online Tuesday, Feb. 1, 2011, in Cell Metabolism, University of Utah human genetics researchers show that this cell division in Drosophila depends on a metabolic ...
New tumor-tracking technique for radiotherapy spares healthy tissue, could improve cancer treatment
2011-02-02
PHILADELPHIA—Medical physicists at Thomas Jefferson University and Jefferson's Kimmel Cancer Center have demonstrated a new real-time tumor tracking technique that can help minimize the amount of radiation delivered to surrounding healthy tissue in a patient—up to 50 percent less in some cases—and maximize the dose the tumor receives.
Respiratory and cardiac motions have been found to displace and deform tumors in the lung, pancreas, liver, breast, and other organs. Because of this, radiation oncologists must expand the margin during radiotherapy. Consequently, a large ...
BIDMC researchers conclude nonprofit hospices disproportionately care for costly patients
2011-02-02
BOSTON – For-profit hospice agencies had a higher percentage of patients with diagnoses associated with less skilled care and longer lengths of stay (LOS) in hospice, than their nonprofit counterparts, a difference that may leave "nonprofit hospice agencies disproportionately caring for the most costly patients," Beth Israel Deaconess Medical Center researchers report.
The findings appear in the Feb.2 issue of the Journal of the American Medical Association (JAMA).
"There was a big increase in the number of for-profit hospice agencies from 2000 to 2007, and previous ...
Internet addresses: An inevitable shortage, but an uneven one
2011-02-02
As Internet authorities prepare to announce that they have handed over all of the available addresses, a USC research group that monitors address usage has completed the latest in its series of Internet censuses.
There is some good news, according to computer scientist John Heideman, who heads a team at the USC Viterbi School of Engineering Information Sciences Institute that has just released its results in the form of a detailed outline, including a 10-minute video and an interactive web browser that allows users to explore the nooks and crannies of Internet space themselves.
video: ...