Researchers Probe Why Colds Are More Likely in Winter

Animal study suggests body's defense system doesn't seem to work as well at cooler temperatures

By Alan Mozes

HealthDay Reporter

TUESDAY, Jan. 6, 2015 (HealthDay News) -- Though it's never been scientifically confirmed, conventional wisdom has it that winter is the season of sniffles.

Now, new animal research seems to back up that idea. It suggests that as internal body temperatures fall after exposure to cold air, so too does the immune system's ability to beat back the rhinovirus that causes the common cold.

"It has been long known that the rhinovirus replicates better at the cooler temperature, around 33 Celsius (91 Fahrenheit), compared to the core body temperature of 37 Celsius (99 Fahrenheit)," said study co-author Akiko Iwasaki, a professor of immunobiology at Yale University School of Medicine.

"[But] the reason for this cold temperature preference for virus replication was unknown. Much of the focus on this question has been on the virus itself. However, virus replication machinery itself works well at both temperatures, leaving the question unanswered," Iwasaki said.

"We used mouse airway cells as a model to study this question [and found that] at the cooler temperature found in the nose, the host immune system was unable to induce defense signals to block virus replication," Iwasaki explained.

The researchers discuss their findings in the current issue of the Proceedings of the National Academy of Sciences.

To explore the potential relationship between internal body temperatures and the ability to fend off a virus, the research team incubated mouse cells in two different temperature settings. One group of cells was incubated at 37 C (99 F) to mimic the core temperature found in the lungs, and the other at 33 C (91 F) to mimic the temperature of the nose.

Then they watched how cells raised in each environment reacted following exposure to the rhinovirus.

The result? Fluctuations in internal body temperatures had no direct impact on the virus itself. Rather, it was the body's indirect immune response to the virus that differed, with a stronger response observed among the warmer lung cells and a weaker response observed among the colder nasal cells.

And how might outdoor temperatures affect this dynamic?

View the original article here

FDA Shares Advice to Avoid Colds and Flu

Influenza virus is spread by sneezing, talking and touching contaminated surfaces

By Mary Elizabeth Dallas

HealthDay Reporter

FRIDAY, Jan. 2, 2015 (HealthDay News) -- Viral infections can happen at any time, but they're more common during winter when people spend more time in close contact with others indoors.

Although most respiratory viruses clear up within a few days, some can lead to dangerous complications, particularly for smokers, the U.S. Food and Drug Administration reports. Signs of complications include: a cough that interrupts sleep; persistent, high fever; chest pain; or shortness of breath.

Unlike colds, the flu comes on suddenly and lasts more than a few days. Each year, more than 200,000 people in the United States are hospitalized from flu complications, and thousands die from flu, according to the U.S. Centers for Disease Control and Prevention. In the United States, flu season peaks between December and February.

Although colds and the flu share some signs, the flu can lead to more serious symptoms, including fever, headache, chills, dry cough, body aches and fatigue. Influenza can also cause nausea and vomiting among young children, the FDA said in a news release.

The flu virus is spread through droplets from coughing, sneezing and talking. It can also infect surfaces.

The best way to protect yourself from the flu is to get vaccinated every year, the FDA said. Flu viruses are constantly changing so the vaccines must be updated annually. The flu vaccine is available as an injection or a nasal spray.

Although it's best to get the flu vaccine in October, getting it later can still help protect you from the virus, the agency said.

With rare exceptions, everyone 6 months of age and older should be vaccinated against flu, federal health officials say. Vaccination is especially important for those at greater risk for flu-related complications, including seniors, pregnant women and children younger than 5 years, people with chronic health conditions, health care providers and caregivers for young children and the elderly.

There is no vaccine for colds. But measures to prevent the spread of viruses include the following:

Wash your hands frequently. Use soap and water when possible. If necessary, an alcohol-based hand sanitizer can help.Avoid exposure to infected people.Eat a healthy well-balanced diet.Get enough sleep.Exercise regularly.Ease stress.

View the original article here