Reported incidents of ticks spreading Lyme disease to pets and humans is rising nationwide, said Karon Damewood, the chief of the Center for Veterinary Public Health at the Maryland Department of Health and Mental Hygiene in Baltimore.
"I'm a big advocate of more public education about Lyme disease," Damewood said.
Byers diagnosed several dogs that live north of the Potomac River in largely residential areas. He said he expected to see more cases west of the river in a dense wooded area prone to a higher number of black-legged ticks and white-tailed deers. The ticks carry the disease and white-tailed deer are major hosts for ticks.
"Ninety percent of all dogs with positive Lyme tests, exposed and clinical, were living in the Hagerstown and Smithsburg areas," Byers said.
His survey proved that infected pets can live in areas where the black-legged tick population is low. However, contact with an infected tick may occur in a different location.
"It typically takes an infected tick 24 to 36 hours to infect a host," said John Carroll, an entomologist with the United States Department of Agriculture. Infection is less likely if ticks are discovered and removed within that time frame, he said.
The potential of catching Lyme disease will increase for dogs, cats and pet owners as summer approaches.
"The black-legged tick will start to multiply in May and June. It declines in July," said Carroll, who has spent the last 15 years studying tick behavior and ecology.
And while the USDA doesn't track tick populations locally, Carroll said the tick population in 2003 grew slightly at USDA tick testing sites in Baltimore, Anne Arundel and Prince George's counties.
"This followed a small tick decline in 2001 and 2002 due to possibly drier summers," he said.
In 2004, Maryland was among the top 10 states with the highest number of reported Lyme disease cases, according to the Centers for Disease Control and Prevention's most recent morbidity and mortality weekly report. Carroll said in the past 10 years, the USDA has seen an increase in reported Lyme disease cases in Washington and Frederick counties as the disease moves further west.
Dogs exposed to areas with high black-legged tick populations are vulnerable and cats also are susceptible. However, Lyme disease cases in cats are less common.
"It's easier for a tick to attach to a dog because dogs don't groom as aggressively as cats do," Byers said.