Another Tick-Borne Infection Is Detected in Humans

Researchers have for the first time detected in humans a certain tick-borne bacterial infection that was thought to sicken only dogs.

The study gives no evidence to suggest that man's best friend is spreading the potentially deadly disease to people directly, through a bite or a lick. Instead, the researchers said ticks are biting both humans and dogs, and may be jumping from dog to master in some cases.

The doctors found four human cases of the infection, all in Missouri, in 1996-98, and four more cases during this tick season in Missouri, Tennessee and Oklahoma.

The study, published in today's New England Journal of Medicine, examined a little-known, yet emerging disease called ehrlichiosis, which is similar to Lyme disease. Both diseases are transmitted by ticks and exist primarily in New England and the upper Midwest.

Two forms of ehrlichiosis have previously been documented in people since 1986, when the disease was first found in the United States. Since then, approximately 1,200 cases have been reported, according to the Centers for Disease Control and Prevention.

But this was the first time researchers found cases of the type of ehrlichiosis that previously had been identified only in dogs.

No matter which form of bacteria causes the infection, an antibiotic can essentially cure it, both in humans and dogs. In the study, all four patients from 1996-98 were treated successfully.

Ehrlichiosis and Lyme disease have some symptoms in common -- headache, nausea, chills, fever, malaise and fatigue -- but typically, ehrlichiosis doesn't usually come with a rash and can be fatal if left untreated. Up to 5 percent of cases result in death.

Heart Valve as Predictor

The hardening or thickening of a tiny heart valve -- a common condition among the elderly that doctors usually dismiss as inconsequential -- may, in fact, be a powerful predictor of heart attacks and strokes.

Previous studies have shown that a severe narrowing or blockage in the left aortic valve is a predictor of heart disease. A new study, published in today's New England Journal of Medicine, has shown for the first time that a precursor condition called sclerosis can also be a warning sign.

Sclerosis is a hardening or thickening in the aortic valve, often due to a buildup of calcium deposits. The condition is found in roughly 25 percent of adults over 65.

The study offers hope that a simple screening procedure can accurately forecast the risk of heart disease in people with no other symptoms. The procedure, called echocardiography, uses ultrasound to produce a two-dimensional picture of the heart and costs roughly $350 to $600.

The researchers studied the echocardiograms of 5,621 men and women 65 and older. The valve was normal in 70 percent. In 29 percent, the valve was hardening or thickening, but there was no obstruction. The valve was narrowing, meaning there was some degree of obstruction, in 2 percent. Following up five years later, the doctors found that hardening of the valve is associated with a 50 percent higher risk of death from heart disease compared with those whose valves are normal.

The researchers do not believe that sclerosis is a direct cause of death but rather a "marker" for heart disease.