TUCSON, Ariz. -- It only takes one child coming home with the flu for the virus to spread to phones, doorknobs and nearly 60 percent of surfaces in a household, according to a new study published by the Journal of Infection.
The study, conducted by researchers at The University of Arizona, studied
the presence of Influenza A virus, the virus most commonly associated with the
flu, in day care centers and in the homes of families with children enrolled
in the programs. In the centers, researchers found Influenza A on 53 percent
of surfaces tested during the spring. In homes, during March 2003, where one
child had the flu, the number was higher -- 59 percent of all surfaces tested
positive for the virus.
"It may come as a surprise to many parents that we detected high levels of
influenza virus in March," says Stephanie Boone, study co-author and doctoral
candidate in soil, water and environmental science at the University of
Arizona. "However, our study was conducted during a late flu season, similar
to this year's flu season. With flu activity now increasing later than usual,
we need to be extra careful this time of year and do what we can to prevent
the spread of the flu virus even during the early spring months."
The researchers tested the most commonly touched household surfaces,
including phones, refrigerator handles, kitchen faucets and light switches.
Phone receivers were the biggest problem area -- 80 percent tested positive
for the virus. In day care centers, kitchen dishcloths were most likely to
test positive for the virus -- 58 percent -- followed by diaper changing areas
-- 57 percent. In both homes and centers, bathroom surfaces were among the
least contaminated surfaces, a result that did not surprise Boone.
"Most people clean their bathrooms regularly, reducing the likelihood of
germs in those areas," Boone said. "But people rarely think to clean their
phone receivers and they are at the top of the list."
The lower presence of the virus overall in centers also could be related
to cleaning practices. "With so many children in one place, day care centers
typically are careful to follow regular cleaning and disinfecting routines to
reduce the potential transmission of viruses and bacteria," Boone said. "In
fact, we found infant and toddler toys -- where the highest level of germs
could be expected -- actually showed the lowest presence of Influenza A among
all surfaces tested. Day care centers typically disinfect toys at least once
a day."
Previous studies report that the introduction of the flu virus into a
household by one family member can cause disease in about two-thirds of other
family members. The flu is responsible for approximately 38 million missed
school days and 70 million lost workdays each year. According to the Centers
for Disease Control and Prevention (CDC), the flu season is late hitting this
year, with high flu activity only now being reported in many areas of the
country.
"These studies show how easy it is to spread the flu virus from place to
place," says Boone. "Regularly disinfecting commonly used surfaces and
washing hands will help cut down on the amount of viral transmission."
As part of a two-year study on the health of children in day care, the
study -- funded by The Clorox Company -- examined the occurrence of the
Influenza A virus on commonly touched surfaces in eight homes and 14 day care
centers in Tucson, Ariz. Children resided in all of the homes sampled; five
of the eight homes had at least one ill child experiencing flu-like symptoms
for at least three days or more in March 2003 when the homes were tested (the
day care centers referred the homes with ill children). The other three homes
were tested during the summer months when no ill children or adults were
present. All of the homes and day care centers were sampled using a sterile
polyester fiber-tipped applicator swab and the virus was detected using
nucleic-acid based scientific methods.
During March 2003, researchers detected the flu virus on 59 percent of the
surfaces in the homes with ill children; however, the virus was not detected
on any surfaces during the summer months. In the day care centers, 53 percent
of the surfaces tested positive for the flu virus during the spring months
(March through May), but only 23 percent of the surfaces tested positive for the
virus during the fall (September through November). Below is a detailed look at the
key study findings.
The flu virus contaminated various percentages of the following sample
surfaces in homes and day care centers:
Home Surfaces
* Phone receivers (80%)
* Doorknobs (60%)
* TV remotes (60%)
* Microwaves (60%)
* Light switches (60%)
* Refrigerator handles (60%)
Day Care Surfaces
* Kitchen dishcloths (58%)
* Diaper changing areas (57%)
* Bath drains (46%)
* Kitchen drains (45%)
* Toilet seat tops (42%)
* Toilet floors (41%)
According to the CDC, each year in the United States the flu causes
illness in approximately 5 percent to 20 percent of the population, an estimated
200,000 hospitalizations and 36,000 deaths. Because the flu virus is
airborne, it is easily transmitted via coughing, sneezing and talking, placing
nearly everyone at risk for exposure. Areas where people gather, such as
homes, day care centers and offices, are likely locations for catching the
flu.
Generally, cleaning with disinfecting products can help reduce the
possibility of viral transfer, transmission and possible infection. Simple
steps, such as disinfecting commonly touched surfaces at home, in day care
centers and in the workplace can help reduce exposure to germs that could make
you sick.
Source: University of Arizona, Tucson
Robust infectious disease surveillance, including rapid subtyping of influenza A, is essential for early detection, containment, and public health reporting of novel viral threats.