Tick-borne illness known to infect dogs found in humans

July 14, 1999
Web posted at: 5:27 PM EDT (2127 GMT)

(AP) -- 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, between 1996 and 1998, and four more cases during this tick season in Missouri, Tennessee and Oklahoma.

The study, published in Thursday'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.

"This is a much more acute and rapidly progressing disease that can be much more serious because it can be fatal in the most severe cases," said study co-author Dr. Gregory A. Storch of the St. Louis Children's Hospital. "Lyme disease is not fatal. It can become chronic and can produce some significant and annoying manifestations."

Dr. Christopher Paddock of the CDC stressed that ehrlichiosis can be prevented.

"Be aware that if you're out in areas where there are ticks, and this can be hunting, hiking, fishing, camping, you should always check yourself and remove any crawling or attached ticks as quickly as possible," he said.

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