SALT LAKE CITY, Aug. 5 (UPI) -- It's not a secret that children get sick frequently and, as a result, so do their parents. A new study of families shows that even if no person is exhibiting symptoms, some type of viral infection may be in their homes 87 percent of the time -- providing some explanation for why bigger families with more children are sick more of the time.
Researchers in the study also note that some viruses, like rhinovirus, only caused symptoms of infection about half the time. Some viruses also had a tendency to stick around for weeks, even after a patient had recovered.
"A lot families go through wave after wave of illness. In fact, some of the kids we monitored had symptoms for 20 to 25 weeks in a row," said Dr. Carrie Byington, a professor of pediatrics at the University of Utah, in a press release. "This study helps us to understand what is normal in young children, and can help us determine when illness should be a cause for concern."
The Better Identification of Germs-Longitudinal Viral Epidemiology, or BIG LoVE, study followed 26 households with a total of 108 individuals for a year, collecting weekly symptom diaries and nasal swabs. Researchers used polymerase chain reaction, or PCR, based tests for 16 respiratory viruses in the family members.
The study found that childless households were infected with viruses 3 to 4 weeks of the year, and that each additional child in a household increased illness -- households with 1 child tested positive about 18 weeks of the year, and families with 6 children tested positive about 45 weeks of the year, or 87 percent.
Parents who live with small children are 1.5 times more likely to be sick as those under 5 years old were found to have at least one virus present in their mucus 50 percent of the time. In the case of Bocavirus, patients had recovered but the virus was still present in their system for as long as 12 weeks.
The researchers said that understanding how often and for how long viruses can stay in the bodies of family members should be taken into consideration when treating patients. The possibility of a patient testing positive for one virus while actually being infected with another is real.
"If a child comes into the emergency room with severe respiratory illness and tests positive for rhinovirus, it might be a smart idea for doctors to make sure they're not missing something else that could be the cause," said Dr. Krow Ampofo, a professor of pediatrics at the University of Utah.
The study is published in Clinical Infectious Diseases.