Rickettsia parkeri infections diagnosed by eschar biopsy, Virginia, USA.

BACKGROUND: Infection with Rickettsia parkeri is an emerging tick-borne illness, often accompanied by fever and an eschar at the site of tick attachment. We present three cases of R. parkeri in Virginia residents. CASE PRESENTATIONS: Case 1 presented initially afebrile, failed to seroconvert to rickettsial antigens, and was diagnosed by DNA testing of the eschar. Case 2 presented febrile with eschar, no serologies were performed, and was diagnosed by DNA testing of the eschar. Case 3 presented febrile with eschar, serologies were negative for rickettsial antigens, and was diagnosed by DNA testing of the eschar. CONCLUSION: DNA testing of eschars represents an under-utilized diagnostic test and may aid in cases where the diagnosis is not made clinically.

TickBot: a novel robotic device for controlling tick populations in the natural environment.

A semi-autonomous 4-wheeled robot (TickBot) was fitted with a denim cloth treated with an acaricide (permethrin™) and tested for its ability to control ticks in a tick-infested natural environment in Portsmouth, Virginia. The robot's sensors detect a magnetic field signal from a guide wire encased in 80m polyethylene tubing, enabling the robot to follow the trails, open areas and other terrain where the tubing was located. To attract ticks to the treated area, CO2 was distributed through the same tubing, fitted with evenly spaced pores and flow control valves, which permitted uniform CO2 distribution. Tests were done to determine the optimum frequency for TickBot to traverse the wire-guided treatment site as well as the duration of operation that could be accomplished on a single battery charge. Prior to treatment, dragging was done to determine the natural abundance of ticks in the test site. Controls were done without CO2 and without permethrin. TickBot proved highly effective in reducing the overall tick densities to nearly zero with the treatment that included both carbon dioxide pretreatment and the permethrin treated cloth. Following a 60min traverse of the treatment areas, adult tick numbers, almost entirely Amblyomma americanum, was reduced to zero within 1h and remained at or near zero for 24h. Treatments without CO2 also showed reduction of ticks to near zero within 1h, but the populations were no different than the control sections at 4h. This study demonstrates the efficacy of TickBot as a tick control device to significantly reduce the risk of tick bites and disease transmission to humans and companion animals visiting a previously tick-infested natural environment. Continued deployment of TickBot for additional days or weeks can assure a relatively tick-safe environment for enjoyment by the public.