Climate change appears to be changing more than simply our climate: sea level rise, extreme weather events, and even tick populations are a few possible examples.
Studying ticks and the diseases they can carry and spread to humans is critical, and recently Old Dominion University received a $2.5 million grant from the National Institutes of Health to do just that.
“Tick-borne diseases are the leading vector-borne disease in the United States, and these diseases are on the rise,” said ODU researcher Holly Gaff, who will lead the university’s team as they study ticks, their behaviors and the disease they carry. “With changes to climate, habitat fragmentation, and the like, we are likely to continue to see an increase in tick-borne diseases in more areas.”
Hampton Roads is one of the locations likely to see an increase, because both the Lone Star tick and the blacklegged (or deer) tick are present here. The deer tick is relatively new to this area but is known to carry and spread Lyme disease. The Lone Star tick has been around longer and can spread a variety of diseases to humans. Gaff and her team will be looking mainly at the Rickettsia bacteria group (amblyommatus, parkeri, and africae).
The grant will also fund collaboration with researchers at the University of Richmond, the University of Florida, the University of Louisiana at Lafayette, the University of KwaZulu-Natal in South Africa and the University of Zambia.
“The more we can understand about when and where there is an increased risk of tick-borne diseases, the better we can hopefully prevent exposure and reduce disease burden,” Gaff said.
The researchers will seek to understand why and when the ticks are most likely to be infected with the pathogen, which will help them understand when humans are likely to be exposed. Gaff said they will also work to update disease models using the information they gather during field work, lab work, and statistical studies.
Although the focus of their study is the Lone Star tick and Rickettsia, they won’t ignore the deer/blacklegged tick – which is a growing presence in Hampton Roads.
“The biggest behavioral difference we are measuring this summer is the questioning height,” she said.
When a tick, the deer tick specifically, is ready to feed, Gaff said they will generally sit and wait for a host to pass by.
“The height at which that tick chooses to sit will affect if you step on it or if it can grab your ankle as you walk past it. We put ticks in viewing arenas and watch to see the preferred questioning heights of the ticks,” she said.
The teams at the various universities will share field data and techniques for testing ticks for pathogens, as well as tips and tricks that work best for each team.
“We also have the overreaching goal of comparing dynamics for these systems to understand if there are consistent factors that are likely to mean increased disease risk,” she said.
At this time in the Hampton Roads area the prevailing deer tick is the less aggressive variant. But a more aggressive species is currently moving into the Northern Neck and Richmond areas, she added.
“We anticipate that movement to continue into the Hampton Roads area, and so we will continue to monitor that.”
That movement of the more aggressive deer tick, she said, is following the spread of Lyme disease across Virginia.