Nonrandom Distribution of Vector Ticks (Dermacentor variabilis) Infected by Francisella tularensis
2009

Mapping Infected Ticks on Martha's Vineyard

Sample size: 254 publication Evidence: high

Author Information

Author(s): Heidi K. Goethert, Sam R. Telford III

Primary Institution: Cummings School of Veterinary Medicine, Tufts University

Hypothesis

We sought to identify a natural focus of transmission of the agent of tularemia by mapping the distribution of PCR-positive ticks.

Conclusion

We have identified a microfocus where the agent of tularemia stably perpetuates and where genetic diversity is generated.

Supporting Evidence

  • Ticks collected from the identified cluster were 3.3 times more likely to test positive for F. tularensis.
  • The majority of PCR-positive ticks came from a small area of the study site.
  • VNTR analysis revealed 13 different haplotypes of F. tularensis in the ticks.

Takeaway

Researchers found a small area on Martha's Vineyard where infected ticks live, helping us understand how tularemia spreads.

Methodology

Ticks were collected from 85 waypoints over four years and tested for F. tularensis DNA using PCR.

Limitations

The study was limited to a specific geographic area and may not represent broader patterns of tularemia transmission.

Statistical Information

P-Value

p=0.001

Confidence Interval

[95% CI]

Statistical Significance

p<0.0001

Digital Object Identifier (DOI)

10.1371/journal.ppat.1000319

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