The flu is usually gone by now. Dr. Ann Morrill isn't generally prescribing Tamiflu and bed rest in July to her Perry Hall patients. The emergency department at St. Joseph Medical Center in Towson doesn't typically do a dozen flu tests a day this deep into summer.
But the H1N1 influenza virus - commonly called swine flu - continues to spread in Maryland and many other states, even though some experts thought it would have faded away by now across the country.
During the last week of June, the state confirmed 166 new cases - the highest weekly total since the first cases were confirmed here May 4. And officials believe that for every confirmed case, there are many more that go unconfirmed as the sick either don't seek medical treatment or are refused testing. Based on its mathematical models, the Centers for Disease Control and Prevention estimates that as many as 1 million Americans have been sickened by this pandemic flu since the outbreak began.
"It died down in the press quite a bit, so many people think it's gone away," said Dr. Gail Cunningham, who heads the emergency department at St. Joseph. The hospital had a record number of visits in June because of people with flu-like illnesses. "The reality is, it's very much still present."
Dr. Anthony S. Fauci, director of the Bethesda-based National Institute of Allergy and Infectious Diseases, said summer's warm weather and high humidity make it hard for a flu virus to survive. In fact, the seasonal flu strain has disappeared.
But this new strain isn't behaving like the seasonal flu that hits each winter. It keeps infecting more people, despite what the calendar says.
"This is persisting in society," Fauci said. "It's unusual for the flu to do that."
Summer camps are feeling the impact. Sandy Hill Camp in Cecil County sent campers home midway through a two-week session last week after 19 children came down with flu-like symptoms in 48 hours. The Muscular Dystrophy Association canceled more than half of its weeklong camp sessions - including two scheduled for Camp Maria in Leonardtown - on fears that children with already-compromised immune systems could become critically ill if they came down with flu, something that is more likely in a setting of shared cabins and meals in close quarters.
"We decided it was a little too risky," said Bob Mackle, an MDA spokesman.
For the most part, health officials say, the symptoms of this flu strain have been mild to moderate, with 170 deaths nationwide, including one in Maryland. Nearly all who have gotten ill have recovered.
But some have been hospitalized, particularly people with underlying medical conditions and already-suppressed immune systems. There have also been cases of otherwise healthy people who have been hospitalized with flu.
"If you get it, you feel like you've been hit by a train," said Dr. Harold Standiford, an epidemiologist at the University of Maryland Medical Center. "But in terms of causing serious illness, we're very fortunate that it has not done that very often.
At the Maryland Department of Health and Mental Hygiene's laboratory, where swabs are being sent to test for the H1N1 virus, technicians are on the lookout for whether the virus is mutating. They are concerned that swine flu could become resistant to Tamiflu (so far there are no reports that it has done so in the United States) or could become more severe. At this point, tests are only being done on swabs from people who are seriously ill.
Seasonal flu in a typical year kills 36,000 people in the United States, primarily the elderly. Children and young adults have been more susceptible to the new H1N1 strain. Some doctors believe that older people might have been exposed to similar strains of flu decades ago and that could be providing some protection.
Seasonal flu tends to peak between December and February, and the state usually stops monitoring for it in mid-May. But this year, Maryland health officials have continued the monitoring program, getting regular reports from private doctors, public clinics and hospitals.
The trend is definitely upward: During the last week in May there were 23 confirmed cases of H1N1; during the last week of June there were 166. There are 578 confirmed cases in Maryland, but some officials say those numbers might be meaningless because there are believed to be thousands of people who have gotten ill but have not been tested for the virus.
At St. Joseph, 174 rapid flu tests were given in the past two weeks and most came back negative. Cunningham said she believes the test "may be inaccurate."
"It's not picking up the cases," she said.
Morrill, the Perry Hall doctor, has had such a hard time getting her patients tested that when she sees someone sick with flu-like symptoms she assumes it is the H1N1 virus and prescribes Tamiflu.
Many influenza researchers had expected swine flu to disappear this summer because that is how previous pandemics have behaved. In the 1918 pandemic, flu appeared in the spring and slowed down in the summer, only to rev up again in fall and winter.
Rene F. Najera, an epidemiologist with the state health department, said Maryland is now in an "acceleration phase" of the flu and he expects the peak to hit soon. He said "herd immunity" will force the flu to slow its pace.
"We'll hit a critical point where so many people are infected or recovering that it will be hard for it to jump from one person to the next," he said.
Cunningham said she expects cases to stay steady before increasing this fall.
It is unclear what this summer of flu could mean when it's actually flu season again. In the Southern Hemisphere, where flu season is just beginning, Argentina, Australia and other nations are reporting H1N1 outbreaks.
While there has long been a vaccine for seasonal flu, there isn't one for swine flu. Development is under way but the U.S. Department of Health and Human Services has not decided whether a vaccine will be mass produced. If that decision is yes, the agency's secretary has suggested that 600 million doses of vaccine would have to be manufactured.
Dr. William Schaffner, an infectious diseases expert at Vanderbilt University, said he worries that H1N1 is off the radar screens of most people - and of doctors.
"What I have seen among patients and some physicians is, they're kind of blowing it off," he said. "They're kind of nonchalant about it.
"If people don't take it seriously, if vaccine is going to be administered, they won't take advantage of it."
Tips for avoiding H1N1 flu
* Wash your hands often with soap and water.
* Cover your nose and mouth when you cough or sneeze.
* Avoid close contact with sick people.
* If you have flu-like symptoms, stay home to keep from infecting others and spreading the virus.
Source: Centers for Disease Control and Prevention