The new year started with a cough and sneeze for many in the San Joaquin Valley.
Fresno doctors and nurses said waiting rooms are full of people complaining of upper respiratory viruses.
"That's all we're seeing -- that seems to be 99% of our patients," said Debbie Favil, a lead medical assistant at the Peachwood Medical Group Urgent Care in Fresno.
Cough, sore throat, fever and body aches are the common symptoms, Favil said.
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But only a few cases are caused by the flu, doctors say.
The bug of the moment is respiratory syncytial virus, or RSV.
Kaiser Permanente tested 700 people with respiratory complaints last week and found 271, or 39%, positive for the virus, said Dee Lacy, an infectious-disease doctor at the Kaiser hospital in Fresno.
The virus causes a cough and sometimes fever and chills in adults and school-age children. Adults can wheeze for months after the infection leaves, she said.
Anyone with a fever that lasts longer than four days should see a doctor, because other infections could develop, Lacy said.
And the wintertime virus in some infants can be life-threatening if it inhibits breathing. RSV can cause inflammation of the bronchioles, or small airways in the lungs. Babies with this virus need to be seen by a doctor.
At Children's Hospital Central California in Madera County, admissions for the virus doubled in the past two weeks of 2007, said Micheline Golden, hospital spokeswoman.
Thirty children with RSV were admitted to the hospital last week, she said.
This could be the beginning of a bad RSV season. The virus makes an appearance every year, but some years are worse than others. "Usually these viruses have a low year and a high year for no reason anyone can discern," Golden said. "And last winter was a low virus winter."
Lacy expects to see more patients with respiratory viruses once school resumes in Fresno on Monday. When children are together, they spread viruses, she said. "We'll see how many children are able to go back to school next week."
And it's also only the beginning of flu season.
Some cases have been identified in the community, Lacy said. But it hasn't yet reached its peak.
The past few years, flu season started in October and was over by Christmas. But this year it's following a more typical pattern, she said. Flu season usually doesn't arrive in full force until January.
"We're probably at the beginning of it," Lacy said. And it's not too late to get a flu shot to protect yourself, she said. "Please come and get vaccinated."