Tick Life Cycles, Host Relationships, and Disease Tracking in a Texas Forest

Jenn Hoskins
22nd August, 2025

Tick Life Cycles, Host Relationships, and Disease Tracking in a Texas Forest

Surveillance grids were established within the pine-dominated (Pinus spp.) Sam Houston National Forest, Texas, to characterize tick ecology in an area of high human recreational activity.

Image adapted from: Salomon et al. / CC BY (Source)

Key Findings

  • This Texas study investigated tick activity, host preferences, and pathogen presence in Sam Houston National Forest over one year
  • Tick activity varied by species and life stage, with lone star ticks most abundant in spring/summer and blacklegged ticks peaking in winter
  • Researchers identified several Rickettsia bacteria within ticks, but found no evidence of Borrelia burgdorferi, the Lyme disease bacterium
Tick-borne diseases are an increasing public health concern globally[2]. These diseases, transmitted by ticks, range from viral infections like tick-borne encephalitis to bacterial illnesses such as Lyme disease. The expansion of tick populations into new geographical areas is a major driver of this rise in cases, particularly in the northern hemisphere[2]. Understanding the life cycle of ticks, which hosts they feed on, and what pathogens they carry is crucial for effective disease management. A recent study by researchers at Texas A&M University and the University of Minnesota[1] investigated these factors in Sam Houston National Forest, a popular recreational area in east Texas. The study focused on four tick species: Amblyomma americanum (the lone star tick), Dermacentor variabilis (the American dog tick), Ixodes scapularis (the blacklegged tick), and Ixodes texanus. Researchers conducted monthly sampling over a year, collecting ticks directly from the environment (“questing” ticks) and from 150 wildlife hosts representing 18 different species, including rodents, mammals, deer, reptiles, and amphibians. They analyzed blood and tissue samples from the animals and tested the collected ticks for the presence of several disease-causing bacteria. The results revealed distinct patterns in tick activity. Amblyomma americanum larvae were most abundant in July, with peak infestations observed on raccoons in August. In contrast, Ixodes scapularis larvae peaked in the spring (March-May), but were rarely found on hosts during the study period. Interestingly, adult Ixodes scapularis ticks were most commonly found in winter. These findings highlight the complex phenology, or timing of life cycle events, of these tick species. Importantly, the study also identified several bacteria within the ticks. Rickettsia buchneri, Rickettsia amblyommatis, and Rickettsia tillamookensis were found in 25.3%, 15.5%, and 8.0% of ticks, respectively. A single tick tested positive for a Borrelia species causing relapsing fever, but notably, no ticks were found to carry Borrelia burgdorferi, the bacterium responsible for Lyme disease. This research builds upon prior work demonstrating the geographical expansion of tick vectors and the associated rise in tick-borne diseases[2][3]. The study’s focus on a newly invaded site, as seen in research on Ixodes scapularis in the north-central United States[4], is particularly valuable. The findings in Texas suggest a different ecological dynamic compared to other regions. For example, the research on Ixodes scapularis in the Upper Midwest found a relatively low prevalence of highly pathogenic strains of Borrelia burgdorferi[4], and the Texas study similarly found no presence of the bacterium. The observed differences in tick abundance and host association, particularly the limited presence of Ixodes scapularis on hosts, may explain the relatively low incidence of Lyme disease in this region. The study also contributes to the understanding of co-feeding transmission, where ticks feeding alongside each other can transmit pathogens[5]. While the study didn't directly investigate co-feeding, the patterns of tick activity and host association could influence the likelihood of this transmission mode. The data gathered by fills critical knowledge gaps regarding tick-borne disease risk in pine-dominated forests, an environment not extensively studied previously. The characterization of tick phenology, tick-host associations, and the bacteria they carry provides a baseline for future monitoring and risk assessment.

EnvironmentWildlifeEcology

References

Main Study

1) Tick phenology, tick-host associations, and tick-borne pathogen surveillance in a recreational forest of East Texas, USA

Published 21st August, 2025

https://doi.org/10.1371/journal.pone.0330826

Related Studies

2) Emerging tick-borne pathogens of public health importance: a mini-review.

https://doi.org/10.1099/jmm.0.001206

3) The Need for a National Strategy to Address Vector-Borne Disease Threats in the United States.

https://doi.org/10.1093/jme/tjz074

4) Synchronous phenology of juvenile Ixodes scapularis, vertebrate host relationships, and associated patterns of Borrelia burgdorferi ribotypes in the midwestern United States.

https://doi.org/10.1016/j.ttbdis.2011.11.004

5) Co-feeding transmission in Lyme disease pathogens.

https://doi.org/10.1017/S0031182014001486


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