Scientists Check Off Another Virus Carried by Ticks
Lyme disease? That’s old news.
Scientists have discovered a new virus carried by ticks. And they say it is just the beginning, now that the spotlight on Lyme disease has sparked new interest in the biting, bloodsucking bugs.
“There are viruses and bacteria that we don’t know about simply because we haven’t looked,” said Duane Gubler, who studies tick diseases at the federal Centers for Disease Control and Prevention. “I think as we study them, we are going to find even more.”
Besides the well-known Lyme disease, scientists know of at least seven illnesses caused by tick bites. Now researchers at Harvard University, at Yale University and in Spain have isolated a new virus in deer ticks in New England. They aren’t sure how it will affect human health, but related viruses discovered in Europe cause severe brain swelling and even death.
“If it does actually affect humans here, the potential for severe illness is there,” said Sam Telford, a parasitologist at the Harvard School of Public Health, who wrote about the new virus in the April-June issue of the CDC’s journal, Emerging Infectious Diseases.
Telford and a team of scientists discovered the virus while studying bacteria that cause human granulocytic ehrlichiosis, a potentially fatal illness identified last year that is caused by black-legged ticks.
The team was studying the salivary glands of ticks when it came across the virus. The team injected the virus into mice to study its effects. The mice quickly died.
“Just the fact that deer ticks have a virus is cause for concern,” Telford said. “That’s why we are aggressively looking at what this means for public health.”
The tiny tick is proving to be a terror; reported cases of Lyme disease reached record levels in 1996. The pests have multiplied in the last few years, thanks to snowy winters that preserve their nests and rainy springs that give them the perfect place to thrive.
There are more than 850 species of ticks worldwide, at least 100 of which transmit disease. Other tick-borne diseases often go undiagnosed because they mimic Lyme disease and its flu-like symptoms. They include babesiosis, Rocky Mountain spotted fever, Colorado tick fever, tularemia and ehrlichiosis.
Most ticks favor animals over humans, but when hungry they feed where they can.
“We think it’s likely that people are being bitten once and infected with more than one agent,” said Thomas Mather, an entomologist at the University of Rhode Island. “That’s why we think one person may get sicker than another.”
Karen Forschner started the Hartford, Conn.-based Lyme Disease Foundation after her 6-year-old son, Jamie, died from the illness. She describes the bugs as cesspools. “A tick can suck the blood from a variety of animals before it dies,” she said. “You are getting a mix of infections.”
Ticks and the diseases they can transmit will continue to thrive as people move into their hide-outs, the CDC’s Gubler said. Besides woods, ticks can be found in meadows, weeds, caves and cabins, and on lawns.
“We have more and more people moving into secondary forests,” he said. “We are going to see more and more of this.”
