How Lyme Pathogens Change Tick Behavior and Survival

Research suggests that pathogens carried by ticks may alter tick behavior in ways that improve their survival and increase the likelihood of disease transmission. Infections with organisms such as Borrelia, Anaplasma, and Babesia appear capable of manipulating tick biology, potentially increasing the tick’s ability to locate hosts and spread infection.

In the article, “Pathogens Manipulating Tick Behavior—Through a Glass, Darkly,” Benelli reviews research describing how infections with Anaplasma, Borrelia, Babesia, Bartonella, Rickettsia, and tick-borne encephalitis virus (TBEV) may influence tick behavior and physiology.¹

You might assume that a deer tick would be weakened by infection. However, evidence suggests the opposite. Deer ticks infected with pathogens such as Borrelia, Anaplasma, or Babesia may actually be more likely to survive.

How Do Pathogens Change Tick Behavior?

Benelli describes several behavioral and physiologic changes that occur in infected ticks that may enhance their survival.

• Greater mobility. Nymphal deer ticks infected with Borrelia were able to climb higher, faster, and longer than ticks that were not infected. This increase in mobility may boost the tick’s questing behavior.
• Questing for hosts. Questing is the behavior ticks use to locate hosts. Ticks climb vegetation and extend their front legs, waiting to attach to passing animals or humans.
• Faster feeding. Deer ticks infected with Borrelia may engorge more quickly by up-regulating the tick histamine release factor, which helps the tick feed more efficiently.
• Enhanced feeding from other infections. Infections with Babesia and Bartonella may also increase the tick’s ability to engorge.
• Resistance to drying. Infection with Borrelia and Anaplasma can increase a tick’s resistance to desiccation. Borrelia may increase the tick’s fat reserves, while Anaplasma stimulates the synthesis of heat shock proteins.
• Improved cold survival. Anaplasma infection enables ticks to produce an antifreeze glycoprotein, helping them survive colder temperatures.

These changes suggest that infection can manipulate tick physiology in ways that improve survival and increase the likelihood that infected ticks will successfully transmit pathogens to hosts.

The author concludes that “being infected by Anaplasma, Borrelia, and Babesia leads to increased tick survival.”

Why Tick Behavior Matters for Lyme Disease Risk

Changes in tick mobility, feeding behavior, and environmental tolerance may increase the chances that infected ticks will encounter humans and animals. These findings may help explain why infected ticks play an important role in the spread of tick-borne infections such as Lyme disease and other tick-borne co-infections.

These findings also help explain why infected ticks may contribute to overall tick exposure risk in endemic areas.

Understanding tick behavior is important for preventing tick bites and reducing the risk of Lyme disease.

Clinical Perspective

Research suggesting that pathogens influence tick behavior raises important questions about whether infected ticks may be more efficient at transmitting disease than previously recognized. These findings reinforce the importance of tick bite prevention and early recognition of Lyme disease symptoms.

Benelli stresses the need for additional research to better understand how different pathogen infections influence tick behavior and transmission.

Dr. Daniel Cameron, MD, MPH
Lyme disease clinician with over 30 years of experience and past president of ILADS.

Symptoms • Testing • Coinfections • Recovery • Pediatric • Prevention