LYME DISEASE RISK ASSESSMENT, CAMP CURTIS GUILD, READING, MASSACHUSETTS, 15-18 JUNE 1992 DEPARTMENT OF THE ARMY U.S. Army Environmental Hygiene Agency Aberdeen Proving Ground, Maryland 21010-5422 [Seal of Department of Defense, United States of America] REPLY TO ATTENTION OF: HSHB-MR-E 30 JUL 1992 LYME DISEASE RISK ASSESSMENT NO. 16-44-AL13-92 CAMP CURTIS GUILD READING, MASSACHUSETTS 15-18 JUNE 1992 1. REFERENCES. a. AR 40-5, 15 October 1990, Preventive Medicine. b. AR 420-76, 3 July 1986, Pest Management Program. c. Memorandum, USAEHA, 19 May 1992, subject: Lyme Disease Risk Assessment, Camp Curtis Guild, Massachusetts, Project No. 16-44-AL13-92. 2. AUTHORITY. AEHA Form 250-R, NGB, 5 August 1991. 3. PURPOSE. To evaluate the risk of Lyme disease to Camp Curtis Guild (CCGD) personnel, by dragging vegetation and examining white-footed mice for the tick vector, Ixodes dammini, and assay collected ticks for the etiologic agent, Borrelia burgdorferi. 4. GENERAL. a. Personnel Contacted. Eleanor Babij, State Environmental Specialist, Massachusetts Army National Guard. b. Survey Performance, The field survey was conducted by 1LT Sandra Alvey, Entomologist and SPC James Richardson, Entomological Sciences Division of this agency, on 15-18 June 1992. c. Survey Site. CCGD is located in Massachusetts, 2 miles northeast of Reading and approximately 20 Miles north of Boston, in Middlesex County. The terrain is generally flat, swampy areas along the north and west sides. Some areas are wooded. This site is used primarily for weapons training, there is very little troop training. d. Technical Assistance. Technical assistance or further informal advice may be obtained by contacting the Entomological Sciences Division (ESD), USAEHA, Commercial Phone 410-671-3613. (DSN 584-3613). 5. METHODS. a. Risk Definition. The term "risk," as used in this report, is a nonstatistical evaluation of qualitative and quantitative information available to determine the potential to acquire Lyme disease. To the extent available, information evaluated includes the following elements: Past history of Lyme disease in the area, the presence or absence of the tick vector and the mammalian host population needed to sustain a viable population of the vector, and the presence of B. burgdorferi or antibodies to Lyme disease in the tick population or mammal host population respectively. Criteria for risk categorization follows: Low risk - Some elements of the Lyme disease cycle identified in nearby areas but not on the installation. Moderate risk - Elements of Lyme disease cycle identified from the installation or human cases of Lyme disease reported from the local area. High risk - All elements of the Lyme disease cycle present on the installation. b. Tick Collection. Sherman live capture traps baited with a peanut butter and oatmeal mixture were placed in wooded areas. The areas selected had been identified as the best woodland mouse habitats for small mammal surveys. During the period of 15-18 June a total of 200 traps were set overnight for two consecutive nights. Mice captured were taken indoors, anesthetized, and examined under a dissecting microscope for ectoparasites. Following examination, mice were returned to the trap location where trapped and were released. During examination hair was stroked contrary to the natural lay, and ticks were removed by using fine-point (No. 5) jeweler's forceps. Collected ticks were placed in labeled, 20 ml humidified vials and kept cool (1.5 - 4.5 C). Ticks were also collected off of vegetation using a white flannel drag cloth mounted on a dowel. The cloth was checked every 10 meters for tick removal, while dragging was done in 100 meter increments. Approximately 2000 meters were dragged. Ticks were returned to USAEHA for identification and testing. c. Tick Assays. Ticks were assay via Indirect Fluorescent Antibody (IFA) testing using a monoclonal antibody (H5332) from Kirkegaard and Perry Laboratories, Inc. and a Fluorescien Labeled (FITC) antibody to determine infection rates of the Lyme disease spirochete, B. burgdorferi. 6. RESULTS. a. A total of four ticks were removed from one of two mice captured on 18 June 1992. Two of the ticks were identified as Ixodes dammini larvae and the other two ticks were identified as Dermacentor variabilis. All four ticks were negative for the Lyme disease spirochete, B. burgdorferi. b. Only one tick was removed from the vegetation by dragging method and identified as an adult Dermacentor variabilis. c. There have been no reports of human Lyme disease at CCGD. d. Massachusetts Department of Health reports no cases of human Lyme disease in the town of Reading, the closest population center and located southwest of CCGD, in 1992, one case in 1990, and no cases in 1989. In Wakefield, located south of CCGD, no cases of human Lyme disease have been reported from 1989-1991. In addition, no cases of human Lyme disease have been reported for the town of Lynnfield, east of CCGD, from 1989-1991. The lack of reported cases, as mentioned above, is not representative of the 78 human Lyme disease cases that have been reported for Middlesex county during the period of 1989-1991. 7. DISCUSSION. This survey provides no evidence that the vector and causative agent of Lyme disease are established at CCGD. In addition, there is no historical evidence of the presence of Lyme disease and its vector on the installation and in the immediate area, there is no potential at-risk human population (troops in field training), little availability of suitable animal hosts, and there is a lack of environmental conditions necessary for the occurrence of Lyme disease. 8. CONCLUSIONS. The absence of specimens of I. dammini on white-footed mice and drags, negative Indirect Fluorescent Antibody (IFA) results from the June 1992 survey and a negative case report from the Massachusetts Department of Health would indicate Low Risk of contracting human Lyme disease at CCGD. 9. RECOMMENDATIONS. Initiate surveillance at CCGD only if the mission changes to include troop training, currently the absence of those factors discussed in paragraph 7 make CCGD an area not warranted for continued Lyme disease surveillance. [signature] SANDRA L. ALVEY 1LT, MS Entomologist Entomological Sciences Division APPROVED: [signature] RICHARD D. WELLS Program Manager, Pest Management Entomological Sciences Division