Lyme disease is a serious problem, with 10 times more Americans being infected than previous reports suggested, said the Centers for Disease Control and Prevention (CDC) on Monday.

As many as 300,000 Americans are diagnosed with Lyme disease annually. Only 20,000 to 30,000 cases are reported every year. The CDC has acknowledged that this is because doctors do not report every instance of the disease. The CDC has long known that there are more cases of the tick-borne disease than reported.

"This new preliminary estimate confirms that Lyme disease is a tremendous public health problem in the United States, and clearly highlights the urgent need for prevention," Dr. Paul Mead, chief of epidemiology and surveillance for CDC's Lyme disease program, based in Ft. Collins, Co., said in a statement.

The CDC performed various studies to obtain the new number, seaching the medical billing records of 22 million people, as well as a 2008 survey of patients and laboratories processing blood tests.

Blacklegged ticks carry Borrelia burgdorferi, a bacterium that causes Lyme disease. Symptoms include headache, fever, fatigue and a skin rash called erythema migrans that looks like bull's-eye in the center of the bite. If left untreated, Lyme disease can spread to the joints, nervous system and heart.

"Not everyone diagnosed or treated for Lyme disease is necessarily infected with Borrelia burgdorferi," the CDC wrote. "Nevertheless, these results are consistent with earlier estimates that Lyme disease cases are underreported by a factor of three- to 12-fold."

According to Mead, the study does not show evidence that the disease has become more geographically widespread.

Lyme disease's name comes from Lyme Conn., the town where it was first discovered in 1975. The majority of reported Lyme disease cases come from Connecticut, Delaware, Maine, Maryland, Massachusetts, Minnesota, New Hampshire, New Jersey, New York, Pennsylvania, Vermont, Virgina and Wisconsin.

The deer ticks that transfer Lyme disease can be as small as a poppy seed. The ticks are often found on rodents as well.

 One dose of the antibiotic doxycycline can treat Lyme disease. Sometimes the antibiotic course can take three weeks to a month. According to the CDC, as many as 20 percent of patients suffer long-term symptoms.

"We know people can prevent tick bites through steps like using repellents and tick checks. Although these measures are effective, they aren't fail-proof and people don't always use them," the CDC's Dr. Lyle Petersen said in a statement. "We need to move to a broader approach to tick reduction, involving entire communities, to combat this public health problem."