It's the time of year when parents may dig through children's backpacks to find the dreaded note: "A case of strep throat has been identified in your child's classroom." Fall strep season is in full swing.
"Someone once said, strep infections are an occupational disease of schoolchildren," said Dr. Ed Kaplan, a professor at the University of Minnesota who leads the World Health Organization Collaborating Center for Reference and Research on Streptococci.
Strep throat (technically group A. streptococcus) is one of the most scientifically confounding -- and studied -- bacterial infections. While there are many unknowns, treatment hasn't changed much since you last sucked down syrupy bubblegum-pink medicine: A 10-day course of penicillin is still the gold standard. In fact, unlike other bacteria, there's never been a clinical isolate of group A strep that has resisted it, Kaplan said.
"It's still as exquisitely sensitive to penicillin as it was 50 years ago," Kaplan said. "How many times have you seen or read or heard people talking about the evolution of(bacteria resisting antiobiotics)? For reasons not fully understood, that hasn't happened with strep."
This fall, new guidelines from the Infectious Diseases Society of America (IDSA) suggest a slightly different course of action for adults: Doctors are encouraged to skip the culture and make treatment decision based solely on the rapid test. A new study found that while the rapid test is not 100 percent accurate (it failed 6 percent of the time in the researchers' examination of 20,000 patients), there were no complications from the missed cases.
The cost of a backup test costs $113 at the Cleveland Clinic where the study was done. Although the risk of complication is low, strep can lead to scarlet fever, rheumatic fever, and acute nephritis.
Still, some doctors prefer to skip the rapid test, possibly starting antibiotics depending on a patient's symptoms, and wait for the results of the culture.
"If the rapid test is negative, the sensitivity varies from 50 to 95 percent -- I have seen negatives that are false negatives" Kaplan said.
Complicating the issue of diagnosis is one of strep's puzzles: Some kids seem to be "healthy carriers" of strep, meaning that doctors sometimes see asymptomatic patients whose cultures turn up positive.
"Usually they stop having symptoms if they're healthy carriers, but people can carry it for a long time -- 10 months or more," said Dr. Chris Van Beneden, an epidemiologist at the U.S. Centers for Disease Control and Prevention who helped develop the new IDSA guidelines. "It's one of those things where it's hard to do the studies because people won't tolerate being swabbed over and over."
Kaplan said he's seen people carry the infection for two years with no symptoms.
That's not the only puzzle: One of the most controversial associations with strep is the obsessive compulsive/tic disorder known as PANDAS (Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infections). The condition is described as a combination of tics, obsessions, compulsionsg and other symptoms. While it has made headlines since researchers began studying it in the 1990s, there is still not a definitive connection between the disorder and strep.
"While there are a lot of hypotheses, the data to support those hypotheses is incomplete at best," Kaplan said. "There's been a lot published, but we don't know the true reason for this disease or what causes it."
Scientists do know that there are about 130 different types of Group A Strep. And while there's some evidence of a degree of resistance after exposure, strep isn't limited to a single type per season.
Worst case scenario: several people in your family or in your kid's classroom contract strep and recover, only to wake up a week or two later with another sore throat. Doctors call it the ping-pong effect.
"If it gets so bad, I've had the experience of parents banding together to say this has got to stop, and that's when the school will contact the health department," Kaplan said. "If it looks like an outbreak, they can decide what to do. For example, they could culture everybody in the room and treat those who are positive."
What can parents do?
To lessen the risk of exposure, remind kids to wash hands and cover their cough. Strep is spread by coughing and sneezing."
To ward off reinfection, replace toothbrushes when the patient is no longer contagious, but before finishing antibiotics. Same goes for washing pillowcases.
To help you or your child's stomach handle the antibiotics, current thinking in the alternative medicine world recommends a course of probiotics to counteract the destruction of good bacteria going on in your gut.
© 2012 Discovery Channel