Lyme disease is caused by the bacterium Borrelia burgdorferi and is transmitted to humans by the bite of infected blacklegged ticks," according to the US Centers for Disease Control and Prevention. These ticks are found in wooded areas in rural United States and it is speculated Bush might have picked up the infection at his Crawford ranch although no confirmation was forthcoming.

Bush developed the rash in August last year and could also have picked it up when riding his mountain bike, which happens to be a passion with him. Bush took to mountain bikes after knee problems prevented him from jogging regularly.

Symptoms of Lyme disease include fever, headache, fatigue, and a characteristic skin rash called erythema migrans. This rash often takes a bull’s-eye appearance and is observed in about 80% of Lyme disease patients. President Bush presented with this characteristic rash and showed no other signs of the disease, according to the White House release.

Lyme disease patients who are diagnosed early and receive proper antibiotic treatment usually recover rapidly and completely. That appears to have been the case with President Bush. "It was the standard, recommended treatment for early, localized Lyme disease," said White House spokesman Scott Stanzel.

However if the infection is left untreated, it can spread to joints, the heart, and the nervous system where it can even cause temporary paralysis.

Bush's doctors said he was "treated, with complete resolution and without recurrence." Other than this minor blip, the doctors declared that he was "fit for duty."

"Doctors have determined that the president remains in superior fitness for a man his age -- anybody who's seen him on the bike or out and about certainly knows that -- and that he is fit for duty," said White House spokesman Tony Snow.

The 61-year-old Bush weighed in at 192 pounds, four pounds less than last year. He is a known enthusiast for workouts and that have resulted in a trim frame. Bush has a resting pulse rate of 52 beats per minute and a resting blood pressure of 117/71 of Hg. His cholesterol levels dropped to 170 from 174, however the level of low-density lipoprotein (LDL) or "bad" cholesterol rose a bit.

This year President Bush took his annual physical in several stages and that is why the report was delayed.  However there is no scare as far as his health is concerned and doctors expected him to serve out his remaining term normally in a healthy condition.

Preventing Lyme Disease (Source: CDC)
Reducing exposure to ticks is the best defense against Lyme disease and other tick-borne infections. There are several approaches you and your family can use to prevent and control Lyme disease.
 
* Use repellent, tick checks, and other simple measures to prevent tick bites
* Spray With Deet
* Control ticks around your home and in your community
* Ask your doctor if taking antibiotics after tick bite is right for you
* Learn the early signs of tick-borne illness

A Lyme disease vaccine is no longer available. The vaccine manufacturer discontinued production in 2002, citing insufficient consumer demand. Protection provided by this vaccine diminishes over time. Therefore, if you received the Lyme disease vaccine before 2002, you are probably no longer protected against Lyme disease.