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Updated: Oct 13, 2026
Feeding of Ticks on Animals for Transmission and Xenodiagnosis in Lyme Disease Research
Published on: August 31, 2013
Attempted transmission of Ehrlichia chaffeensis among white-tailed deer by Amblyomma maculatum
A A Kocan1, S A Ewing, D Stallknecht
1College of Veterinary Medicine, Oklahoma State University, Stillwater 74078-2006, USA. aak4453@vms.okstate.edu
Abstract:
A deer was needle-exposed intravenously to Ehrlichia chaffeensis (Rickettsiales: Ehrlichieae) in canine macrophage (DH82) cells and 7 days later was infested with laboratory-reared Amblyomma maculatum (Koch) (Acari:Ixodidae) nymphs for acquisition feeding. After molting, the adult ticks were allowed to feed on a naive deer. The organism was reisolated from the needle-exposed deer by cell culture and E. chaffeensis DNA was detected in the deer's blood by PCR. Similar isolation/recovery techniques were used for the tick-exposed deer and no evidence of infection was found. Although these findings must be considered as preliminary owing to inadequate controls, the data suggest that A. maculatum is probably not a suitable vector for E. chaffeensis.
Insights
Amblyomma maculatum ticks were tested as vectors for Ehrlichia chaffeensis. Despite exposure, these ticks did not appear to transmit the bacteria to a naive deer, suggesting they are not a suitable vector.
Area of Science:
- Veterinary Entomology
- Infectious Diseases
- Parasitology
Background:
- Ehrlichia chaffeensis is a tick-borne pathogen causing disease in mammals.
- Identifying competent tick vectors is crucial for understanding disease transmission dynamics.
Purpose of the Study:
- To evaluate the potential of Amblyomma maculatum as a vector for Ehrlichia chaffeensis.
Main Methods:
- Deer were intravenously inoculated with E. chaffeensis.
- Ticks (Amblyomma maculatum) fed on infected deer for pathogen acquisition.
- Adult ticks subsequently fed on a naive deer to assess transmission.
Main Results:
- Ehrlichia chaffeensis was successfully re-isolated from the initially infected deer.
- E. chaffeensis DNA was detected in the blood of the needle-exposed deer via PCR.
- No evidence of E. chaffeensis infection was found in the deer exposed to ticks that had fed on the infected deer.
Conclusions:
- Preliminary data suggest that Amblyomma maculatum is likely not an effective vector for transmitting Ehrlichia chaffeensis to deer.
- Further studies with improved controls are needed to definitively confirm vector competence.
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