Are Southern Nymphal Deer Ticks Hiding?
Southern nymphal deer ticks may behave differently than those in the Northeast, potentially reducing human exposure.
In their article, Tietjen and colleagues from Texas A&M University explored whether immature stages of Ixodes scapularis reside in leaf litter or soil rather than on vegetation.
Researchers collected samples of leaf litter, topsoil, and subsoil and analyzed them using Berlese funnels to identify hidden nymphal ticks.
No Nymphal Ticks Found
No nymphal ticks were identified in any of the 600 samples—findings that differ from studies in the Northeastern United States.
This raises an important question: where are the immature ticks in the South?
Ticks exhibit two host-seeking behaviors: some remain in nests or burrows, while others actively seek hosts in open environments.
Alternative Tick Behavior in the South
The authors suggest that southern nymphal ticks may rely more on host-associated behavior, possibly attaching to animals such as lizards and dropping off in nests or burrows.
They may also desiccate quickly in hot southern climates if exposed on vegetation, limiting their survival outside protected environments.
These behavioral differences could explain why Lyme disease is reported less frequently in the South compared to northern regions.
Nymphal ticks in the South may still pose a risk, but their interaction with humans may be less frequent.
Challenges in Tick Surveillance
Standard methods such as flagging and dragging may fail to detect immature ticks in the South if they are not actively questing on vegetation.
Although adult Ixodes scapularis ticks are present, the behavior of nymphs remains less well understood.
Clinical Takeaway
Southern nymphal ticks may be less visible but not absent, and differences in behavior may influence Lyme disease risk.
Related Articles
- Evidence of Lyme disease in the South
- More evidence of Lyme disease in the South
- Culture evidence in the Southeast
- Tick-borne disease risk in the South
References
- Tietjen M, Esteve-Gassent MD, Medina RF. Searching for the Immature Stages of Ixodes scapularis in Leaf Litter and Soil in Texas. J Med Entomol. 2018.
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
