LYME DISEASE RISK ASSESSMENT, FORT HUNTER LIGGETT, CALIFORNIA, 12 SEPTEMBER-NOVEMBER 1993 DEPARTMENT OF THE ARMY US Army Environmental Hygiene Activity-West Fitzsimons Army Medical Center Aurora, Colorado 80045-5001 [Seal of Department of Defense, United States of America] REPLY TO ATTENTION OF: HSHB-AW-P (40-5f) 6 December 1993 LYME DISEASE RISK ASSESSMENT NO. 16-66-A1XY-93 FORT HUNTER LIGGETT, CALIFORNIA 12 SEPTEMBER-NOVEMBER 1993 1. REFERENCES. See Appendix A for a list of references. 2. AUTHORITY. a. Conference Report on the National Defense Authorization Act for Fiscal Years 92 and 93, House Report 102-311, 102nd Congress, 1st Session, 13 November 1991, p. 422. b. USAEHA Form 250-R, U.S. Army Health Services Command, 7 July 1992. 3. PURPOSE. The purpose in performing this risk assessment was to survey for Lyme disease vectors, to determine the prevalence of the infective agent, Borrelia burgdorferi, in rodents and ticks, and to assess the risk of Lyme disease to Fort Hunter Liggett personnel. In addition, a survey for hantavirus was conducted concurrently with the Lyme disease work. See Appendix B for other assistance that can be obtained from the U.S. Army Environmental Hygiene Activity-West (USAEHA-W). 4. GENERAL. a. Risk Definition. The term "risk", as used in this report, is a non- statistical determination of qualitative and quantitative information available to evaluate the potential to acquire Lyme disease. To the extent available, information evaluated includes the following elements of the Lyme disease cycle: (1) History of Lyme disease in the area. (2) The presence or absence of the tick vector, Ixodes pacificus and the mammalian host population needed to sustain a viable population of the vectors. (3) The presence of the Lyme disease-causing spirochete, B. burgdorferi, in the tick population or in the mammalian reservoir host population. (4) The presence of antibodies to B. burgdorferi in the mammalian host populations. The criteria for risk categorization are: Low risk - Some element 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 identified from the local area. High risk - All elements of the Lyme disease cycle are present on the installation. b. Major Thomas P. Gargan and Mr. William E. Irwin, the Survey Officers, discussed major findings and recommendations concerning Lyme disease with Fort Hunter Liggett personnel. In addition, Dr. Michael Turell, from the U.S. Army Medical Research Institute for Infectious Diseases (USAMRIID), discussed hantavirus and its ramifications with installation personnel. A list of personnel contacted and personnel assisting the Survey Officers during the risk assessment is found in Appendix C. c. The field survey portion of the Lyme Disease Risk Assessment was conducted at Fort Hunter Liggett on 12-17 September 1993. The laboratory analyses of ticks and rodent ear biopsies were conducted from 23 September- 30 November 1993. 5. BACKGROUND. a. Lyme Disease. (1) Fort Hunter Liggett is located in south central California in Monterey County, 15 miles south of King City. The installation is located on approximately 160,000 acres at an elevation of 400 meters above sea level. The installation is situated just east of the Santa Lucia Range and Los Padres National Forest. The San Antonio River runs south east through the central part of the installation. The central portion is relatively flat and includes the cantonment area, firing ranges, and air strip. The eastern area is hilly with high grass and shrubs. There is a large wild boar population and also a good number of elk and deer on Fort Hunter Liggett. (2) There have been no confirmed cases of Lyme disease reported from Fort Hunter Liggett. Confirmed cases have reported as having originated in Monterey County in the past. There were 221 confirmed cases of Lyme disease reported for 1992 in the state of California (Appendix A, Reference 1). b. Hantavirus. (1) By 21 October 1993, laboratory evidence of hantavirus infection had been confirmed in 42 cases in 12 states. Most of these cases were in the four corners area of the southwest. Two fatal cases have originated in California: a field biologist doing research near the Mammoth Lakes area in Mono County; and a ranch hand working in Santa Barbara County. Both fatalities occurred within four days of the onset of symptoms. This emerging disease, now called Hantavirus Pulmonary Syndrome (HPS), has been fatal in 62 percent of the cases diagnosed to date (Appendix A, Reference 2). (2) In previous studies, hantavirus has been isolated from rodent urine and feces. Because of these findings it is thought that the virus is transmitted by the aerosolation of the dried rodent excreta. Current data suggest that Peromyscus maniculatus, the deer mouse, is the primary reservoir of the virus but other rodents may also carry the infectious agent. (3) Currently, researchers have identified four different serological types of hantaviruses: Hantaan, Puumala, Seoul, and Prospect Hill. In the past, hantaviruses as a group have characteristically been associated with hemorrhagic and renal abnormalities as opposed to the current HPS respiratory complications associated with the "newer strain" of hantavirus. The relationship of the previously described types of hantavirus and the HPS is not fully understood. 6. METHODS. a. Field Survey Procedures. (1) Rodent Surveys. Because of the concern about HPS in California, personal protective equipment was worn while processing rodents. The Lyme disease surveillance portion of this survey was done in conjunction with the hantavirus survey. Rodents were trapped, anesthetized, and identified to species, as described in the USAEHA-W, ESD SOP No. 7. A small ear biopsy was taken from woodrats and kangaroo rats since these rodents are the major reservoir hosts for the spirochete that causes Lyme disease in California (Appendix A, Reference 4). The tissue biopsies were stored on dry ice for later culturing in the laboratory. Each rodent was also examined for ticks which were removed for additional analysis. Rodents trapped at Fort Hunter Liggett were identified using "California Mammals" (Appendix A, Reference 5). All rodents were handled in accordance with the guidelines outlined in the National Institutes of Health Publication No. 85-23, Revised 1985, "Guide for the Care and Use of Laboratory Animals". After the rodents were processed for Lyme disease, they were processed for hantavirus in accordance with USAMRIID guidelines. A blood sample was taken, then two samples from the lung, liver, kidney, and spleen were taken and flash frozen in liquid nitrogen. One set of organ samples was sent to USAMRIID, located at Fort Detrick, Maryland, for analysis, and the other organ set was sent to the National Centers for Disease Control and Prevention (CDC), located in Atlanta, Georgia. (2) Tick surveys. Two ticks were collected by removing them from the ears of rodents trapped on Fort Hunter Liggett. The ticks were kept alive by placing them in water-moistened vials, as described in the USAEHA- W, ESD SOPs No. 6 and No. 8. Both ticks [were] collected on the same rodent. The ticks were kept alive in humidified labeled vials, and subsequently sent to the USAEHA-W, ESD Laboratory for identification and bioassay. b. Laboratory Assay Procedures. (1) All rodent ear biopsies were surface decontaminated, cut into small pieces, and placed in BSK II, a liquid culture medium specially developed to promote the growth of B. burgdorferi. If any of the trapped rodents were serving as the reservoir hosts for Lyme disease, the spirochetes should grow in the medium. (2) All ticks collected from the survey were processed by using either darkfield or immunofluorescent microscopy, culturing, or by using the Polymerase Chain Reaction (PCR) technique. 7. FINDINGS AND DISCUSSION. a. Tick Collection. Two larval I. pacificus were collected from a single California pocket mouse, Perognathus californicus, at Fort Hunter Liggett. This tick is the vector of Lyme disease in the state of California. b. Rodent Collections. Eight species of rodents were captured from nine habitats on Fort Hunter Liggett (see Table). The deer mouse, Peromyscus maniculatus, was the most common rodent captured. c. Lyme Disease Laboratory Results. (1) Ticks. The two ticks were assayed using the PCR technique and were negative for B. burgdorferi. Table. Rodents Collected From Specific Habitats at Fort Hunter Liggett, Jolon, California during 12-17 September 1993. --------------------------------------------------------------------------- Rodents ---------------------------------------------------- Habitat No. Species --------------------------------------------------------------------------- Island Oak with grass 6 Neotoma fuscipes surrounding (Dusky-footed woodrat) 1 Peromyscus truei (Pinon mouse) 1 Perognathus californicus (California Pocket mouse) Dry Creek bed 6 Peromyscus maniculatus Mixed Scrub (Deer mouse) 3 Peromyscus boylei (Brush mouse) 2 Perognathus californicus (California Pocket mouse) Dry Creek bed Mixed 5 Peromyscus maniculatus Woodland and Scrub (Deer mouse) Mixed Woodland 7 Neotoma fuscipes and Scrub (Dusky-footed woodrat) 1 Dipodomys heermanni (Herman's Kangaroo rat) 10 Peromyscus maniculatus (Deer mouse) 2 Peromyscus boylei (Brush mouse) 2 Peromyscus californicus (California mouse) 5 Perognathus californicus (California Pocket mouse) Oak Woodland 2 Neotoma fuscipes (Dusky-footed woodrat) 2 Peromyscus boylei (Brush mouse) 1 Peromyscus californicus (California mouse) Chaparral 4 Neotoma fuscipes (Dusky-footed woodrat) 4 Dipodomys heermanni (Herman's Kangaroo rat) 1 Peromyscus maniculatus (Deer mouse) 15 Peromyscus truei (Pinon mouse) 1 Peromyscus boylei (Brush mouse) 1 Peromyscus californicus (California mouse) 1 Perognathus californicus (California Pocket mouse) Sycamore Woodland 1 Neotoma fuscipes (Dusky-footed woodrat) 1 Peromyscus boylei (Brush mouse) 1 Perognathus californicus (California Pocket mouse) Grassland 1 Spermophilus beecheyi (California ground squirrel) Willow and Scrub 2 Neotoma fuscipes (Dusky-footed woodrat) 2 Peromyscus maniculatus (Deer mouse) 3 Peromyscus truei (Pinon mouse) ------ TOTAL 94 (2) Rodent Ear Biopsies. Twenty-nine rodent ear biopsies were cultured in BSK II media for spirochetes. All samples were negative for B. burgdorferi, suggesting that the spirochete had not circulated within the small number of rodents sampled at Fort Hunter Liggett. d. Lyme Disease Risk. (1) During the field survey portion of this Lyme disease risk assessment, very few ticks were removed from the trapped rodents. The month of September is not a good time of the year to collect ticks from rodents. In a previous survey in January 1989, a number of ticks were collected from drags and rodents (Appendix A, Reference 9). Additional ticks have been collected from deer hunts during the fall over the last two years (Appendix A, References 10 and 11). Information is still needed regarding the distribution of ticks at Fort Hunter Liggett and a continual collection program should be developed. (2) No Lyme disease spirochetes were recovered from either the ticks or from the rodent ear biopsies collected during this assessment. (3) The categorization defined in paragraph 4a was used to determine the human health risk from Lyme disease at Fort Hunter Liggett. The data collected during this assessment indicated that two criteria for acquiring Lyme disease were present; the tick vector, and confirmed local cases of Lyme disease. No human cases have been documented as originating on the installation. Consequently, the Risk Definition criteria suggests a Moderate risk. Because the tick vector was found at Fort Hunter Liggett, the deer population is quite large, and cases of Lyme disease are documented in the local area, Lyme disease could conceivably become a problem on the installation. (4) Although no human cases of Lyme disease have been diagnosed as originating on Fort Hunter Liggett, personal protective measures to guard against tick bites would be prudent. The risk of contracting any tick- borne disease can be minimized by the proper wearing of clothing, avoiding areas known to harbor high tick populations, and the use of repellents (see Appendix D for repellent products available in the Defense General Supply Center or Self-Service Supply System). General Lyme disease reduction measures can be found in Appendix E. A public awareness program stressing prevention of tick bites should be implemented for personnel on the installation. (5) Ticks may be sent to our USAEHA-W, ESD Laboratory at any time; we will identify and analyze submitted specimens for Lyme disease. Continuing surveillance should further define the presence and distribution of ticks and the risk of acquiring Lyme disease on Fort Hunter Liggett. Additional collections of ticks should be made from deer during the hunting season in the fall of 1993, and all trapped rodents should be screened for ticks. Collection kits were left with personnel at the installation. e. Hantavirus Laboratory Results. (1) Survey personnel collected over 950 organ and serum samples from rodents trapped at Fort Hunter Liggett. (2) Two of the rodents captured had hantavirus antibodies. Further tests are being conducted at the USAMRIID to definitively identify the serological type of hantavirus. The following positive rodents were both collected from the Mission Creek area: one Peromyscus maniculatus, from the mixed woodland and scrub habitat; and one Peromyscus truei, the Pinon mouse, from the willow and scrub habitat. f. Hantavirus Risk. (1) Hantavirus is a newly emerging human disease in the United States. Antibodies to the hantavirus group have been found in rodents on Fort Hunter Liggett. These results are similar to other rodent studies conducted in the southwest this year. The finding that hantavirus was present in two species of mice is also consistent with other survey results. Because of the small number of rodents sampled, the data should not be construed to imply any relative measure of safety or danger with respect to this disease. The presence of the virus may vary greatly from one rodent species to the next, and from one site on the installation to another site. Therefore, it would be prudent to use the appropriate personal protective equipment to protect installation personnel from this and other diseases associated with rodents. (2) Personnel at risk of acquiring hantavirus infection are those who may come into contact directly with field rodents or rodent droppings and/or urine. Examples of personnel at risk would include pest controllers, wildlife biologists, personnel living in or disturbing the contents of buildings infested with rodents, maintenance and repair personnel exposed to rodent droppings/urine under or in buildings or other structures, warehouse personnel, and those individuals assigned to clean up areas where rodent droppings are present. (3) In order to minimize the risk of hantavirus, personal protective equipment should be worn by those potentially exposed to rodents or their droppings/urine. This equipment includes: respirator with HEPA filters, goggles, solvent resistant gloves, coveralls, and boots. Areas with rodent droppings/urine which are to be cleaned up should first be treated with a disinfectant. Detailed guidance from the CDC on personal protection for various classes of potentially exposed individuals against hantavirus were published as a special report in the Morbidity and Mortality Weekly Report (Appendix A, Reference 12). The USAEHA fact sheet entitled "Interim Recommendations for Reducing Risk of Hantavirus Infection" (Appendix A, Reference 13) provides additional guidance on this disease. Copies of both documents referenced above were sent to the installation. (4) As with any other disease, a health education program should be instituted to inform installation personnel of the risks and prevention measures concerning hantavirus. 8. CONCLUSIONS. The western black-legged tick, I. pacificus, the vector species of Lyme disease in the state of California, was collected at Fort Hunter Liggett. Borrelia burgdorferi, the causative agent for Lyme disease, was not found on the installation. Lyme disease has been confirmed in Monterey County by county health officials. Personnel training, working or residing on Fort Hunter Liggett are at Moderate risk for acquiring Lyme disease. Implementation of personal protective measures for all military, civilians, and dependents using Fort Hunter Liggett for outdoor training or recreation is recommended. Hantavirus was been [sic] detected in field rodents on the installation. The risk of installation personnel acquiring hantavirus infection is unknown; however, personnel exposed to rodents or their droppings/urine should take adequate precautions and use personal protective equipment to reduce the risk of hantavirus or other rodent-associated diseases. 9. RECOMMENDATIONS. a. Develop a public awareness program to educate civilian employees, visitors, and any troops training on the installation on the risk associated with tick bites and Lyme disease. A synopsis of suggested Lyme disease risk reduction measures can be found in Appendix E. b. Use personal protective measures to protect individuals potentially exposed to ticks as discussed in paragraph 7d(4), this report. c. Collect ticks at Fort Hunter Liggett during different times of the year as discussed in paragraph 7d(5), this report. d. Develop a public awareness program to educate civilian employees, visitors, and any troops training on the installation on the risk associated with field rodents and hantavirus. e. Use personal protective measures to protect individuals potentially exposed to field rodents and their droppings/urine as discussed in paragraphs 7f(2) and (3), this report. [signature] WILLIAM E. IRWIN Lyme Disease Investigator APPROVED BY: [signature] THOMAS P. GARGAN II MAJ, MS Chief, Entomological Sciences Division APPENDIX A REFERENCES 1. Lyme Disease--United States, 1991-1992, Morbidity and Mortality Weekly Report, Volume 42, No. 18, May 1993, Massachusetts Medical Society. 2. Update: Hantavirus Pulmonary Syndrome - United States, 1993, Morbidity and Mortality Weekly Report, Volume 42, No. 42, October 1993, Massachusetts Medical Society. 3. USAEHA-W, ESD SOP No. 7, 25 April 1991, Procedures for Trapping and Handling Small Mammals. 4. Lane, Robert S. and R. H. Brown, Wood Rats and Kangaroo Rats: Potential Reservoirs of the Lyme Disease Spirochete in California, 1991, Journal of Medical Entomology, Vol. 28, No. 3. 5. Jameson, E.W. Jr., and Hans J. Peters, 1988, California Mammals, University of California Press, Berkeley, California. 6. National Institutes of Health Publication No. 85-23, Revised 1985, Guide for the Care and Use of Laboratory Animals, U.S. Department of Health and Human Services. 7. USAEHA-W, ESD SOP No. 6, 24 April 1991, Tick Collection Procedures. 8. USAEHA-W, ESD SOP No. 8, 25 April 1991, Small Mammal Tick and Ear Tissue Collections. 9. Memorandum For Record, this Activity, HSHB-AW-P, 21 February 1989, subject: Lyme Disease Vector Profiles No. 16-66-0511-89, Fort Hunter Liggett, California, 16-27 January 1989. 10. Memorandum, this Activity, HSHB-AW-P, 2 January 1992, subject: Lyme Disease Risk Assessment No. 16-66-AC59-92, Fort Hunter Liggett, Jolon, California, January 1992. 11. Memorandum, this Activity, HSHB-AW-P, 9 March 1993, subject: Lyme Disease Risk Assessment No. 16-66-A1CL-93, Fort Hunter Liggett, Jolon, California, 13 October - 16 February 1993. 12. Hantavirus Infection--Southwestern United States: Interim Recommendations for Risk Reduction, Morbidity and Mortality Weekly Report, Volume 42, No. RR-11, 30 July 1993, Massachusetts Medical Society. 13. Just the Facts, 64-001-0893, Interim Recommendations for Reducing Risk of Hantavirus Infection, USAEHA. APPENDIX B TECHNICAL ASSISTANCE Technical advice and/or consultation on pest management problems, to include on-site assistance, may be obtained by telephone from our Activity at DSN 943-8090. Please inform your Major Command Pest Management Consultant if you desire to request on-site assistance from our Activity. Technical services that we can assist you with are as follows: 1. Entomological laboratory support 2. Environmental laboratory support 3. Hazardous waste management 4. Industrial hygiene management 5. Medical systems safety and health 6. Sanitation and hygiene 7. Wastewater management 8. Water supply management 9. Worksite hazards management 10. Cholinesterase testing management For assistance in any of the above listed programs, please call: Environmental Health and Engineering Division - DSN 943-8100 Field sanitation and hygiene; potable, recreational and wastewater quality; hazardous waste management; document/design reviews. Industrial Hygiene Division - DSN 943-8881 Industrial hygiene; hazard communication; protective equipment programs; document/design reviews. Environmental Laboratory Division - DSN 943-3293 Routine and emergency analysis of water, soil, and occupational health- related samples. Cholinesterase Laboratory Division - DSN 943-4838 Testing of red blood cell-cholinesterase (RBC-ChE) specimens and quality assurance consultations and training for RBC-ChE labs. During non-duty hours calls will be recorded by an answering machine and returned the next day. Many additional services are available from our parent organization, the U.S. Army Environmental Hygiene Agency, and are described in AEHA Pamphlet 40-2, Directory of Services (published annually). We will gladly coordinate any additional services you request and that we cannot provide with our parent organization. APPENDIX C PERSONNEL CONTACTED 1. MAJ Michael T. Olson Executive Officer HQ Garrison, Fort Hunter Liggett Jolon, CA 93928 (408) 385-2505 2. Mr. Heinz Hormann Facility Manager Building 191, Fort Hunter Liggett Jolon, CA 93928 (408) 385-2505 3. Mr. Mark Grindstaff General Foreman Department of Engineering and Housing Building T-151, Fort Hunter Liggett Jolon, CA 93928 (408) 385-2514 4. CPT Henry Banchs Environmental Science Officer U.S. Army MEDDAC Fort Ord, CA 93941 DSN 929-0358/5722 5. Ms. Sylvia Redschlag Installation Pest Management Coordinator Department of Enginnering and Housing Environmental and Natural Resources Division Fort Ord, CA 93941 (408) 242-2825 6. Dr. Michael J. Turrell Applied Research Division USAMRIID, Fort Detrick Frederick, MD 21702 (301) 619-7244 7. Mr. Ed McComas Pest Controller BLD FH-23, Fort Hunter Liggett Jolon, CA 93928 (408) 385-2026 8. Mr. Malcolm A. Thompson State of California Department of Health Services Vector-borne Disease Section Sacramento, CA (916) 387-3145 9. Mr. Charles R. Smith California Dept. of Health Services Environmental Management Branch Vector Surveillance Unit 2135 Akard Avenue, Room 13 Redding, CA 96001 (916) 225-2130 10. Ms Lucia Hui California Dept. of Health Services 2151 Berkeley Way, Room 619 Berkeley, CA 94704 (510) 540-2720 11. Mr. Martin Castro California Dept. of Health Services 50D Street Suite 200 Santa Rosa, CA 95404 (707) 576-2733 12. CPT Leslie Love 55 North Wolfe Edwards AFB, CA 93524-6200 DSN 527-2244 (805) 277-2244 13. Ms. Berryette Enge State of California Department of Health Services Viral and Rickettsial Disease Laboratory 2151 Berkeley Way, Room 454 Berkeley, CA 94704 (510) 540-2128 14. LT Michael J. Medina Department Head Testing and Evaluation Navy Disease Vector Ecology and Control Center NAS, Building 130 Alemeda, CA 94501 (510) 263-2860 15. SPC Lyndon Scott Preventive Medicine Specialist U.S. Army MEDDAC Fort Ord, CA 93941 DSN 929-5812 16. HM2 Jeff Walters LPO Testing and Evaluation Department Navy Disease Vector Ecology and Control Center Nas, Building 130 Alemeda, CA 94501 (510) 263-2860 17. Dr. George Ludwig Applied Research Division USAMRIID, Fort Detrick Frederick, MD 21702 (301) 619-7244 18. SGT Donald Padgent Applied Research Division USAMRIID, Fort Detrick Frederick, MD 21702 (301) 619-7244 APPENDIX D REPELLENTS 1. Several repellent products are available through the Defense General Supply Center (DGSC) or Self-Service Supply System. When used in accordance with label directions and in conjunction with the proper wearing of the uniform, they provide personal protection against a wide variety of medically important insect/arthropod pests. Availability and current pricing can be obtained by calling the DGSC at DSN 695-4865 for: a. Insect/Arthropod Repellent Lotion (cream, 2 fluid ounces), NSN 6840-01-0284-3982. The lotion is not labeled for ticks, but will repel chigger mites and many biting flies. b. Permethrin Arthropod Repellent, Insect Repellent, Clothing Application (aerosol, 6 ounces), NSN 6840-01-278-1336. Seventy-five percent of the can is used to apply to the field uniform and the remainder is used to treat mosquito netting. The product provides protection from ticks and mosquitoes through six normal launderings. c. Insect Repellent Fabric Treatment (liquid, 5.1 fluid ounces), NSN 6840-01-334-2666. The contents are added to 2 gallons of water and applied with the 2-gallon sprayer from a field sanitation kit at a pressure of 50 pounds per square inch to field uniforms, mosquito netting, and tent fabric to provide protection from ticks, biting flies, and other insects. Since most sprayers are not equipped with the required pressure gauge (NSN 3740- 01-332-8746), it will be necessary to obtain a pressure gauge and filter (NSN 4330-01-332-1639), in order to complete the retrofitting. Proper application can provide protection for the normal life of the uniform, six launderings of mosquito netting, and 6-9 months of treatment for tent fabric, depending on the climate. 2. Detailed directions for the use of these and other repellents can be found in the U.S. Army Environmental Hygiene Agency Technical Guide (TG) 174, Personal Protective Techniques Against Insects and Other Arthropods of Military Significance. 3. The U.S. Army Medical Department Tick-Borne Disease Card (7189) is available from the USAEHA-W, ESD. APPENDIX E LYME DISEASE RISK REDUCTION MEASURES 1. Emphasize public awareness programs to educate troops, dependents, civilian employees, and visitors on personal protective measures and Lyme disease. Methods should include but are not limited to: a. Distribution of printed Lyme disease handouts such as tick identification cards (USAMD-7189), pamphlets, and fact sheets. b. Notifications in the installation newsletter, especially prior to the high-risk months (April to September). c. Making available video and 35mm slide format presentations on Lyme disease; both are available from this Activity. 2. Forward any collected live tick specimens (either field-collected ticks or those that have been removed from individuals) for identification and immunofluorescent staining or darkfield microscopy testing to the Entomological Sciences Division, U.S. Army Environmental Hygiene Activity- West, Fitzsimons Army Medical Center, Aurora, CO 80045-5001. 3. Stock Permethrin Arthropod Repellent (NSN 6840-01-278-1336, box of 12 cans for $36.99), and 3M [Trademark] Insect Repellent (NSN 6840-01-284- 3982, box of 12 tubes, $29.30) for distribution. Emphasize tick habitat avoidance, proper wearing of clothing, and use of repellents. 4. Report all confirmed and suspected cases of Lyme disease [e.g., suspicious febrile illnesses, arthralgias, rashes, (erythema migrans)] by special telegraphic report [MED-16(R4)] for all soldiers and civilian beneficiaries. 5. Identify high-risk foci in cantonment areas via tick dragging/flagging, small mammal trapping, deer checks and the assaying of collected ticks for Borrelia burgdorferi. Sampling should be performed in early spring when Ixodes pacificus nymphs (the life stage responsible for most human Lyme disease infections) are active. 6. Post DA Poster 40-5, and thereby identify high-risk areas. DA Poster 40-5 can be obtained by writing to the Commander, U.S. Environmental Hygiene Agency, ATTN: HSHB-MR-E, Aberdeen Proving Ground, MD 21010-5422, or telephone DSN 584-3613 or Commercial (410) 671-3613. 7. Avoid high tick population areas for troop training or recreation. Such areas can be identified by dragging or flagging for ticks prior to use. Case-by-case surveillance is necessary due to the patchy distribution of I. pacificus. 8. Eliminate tick habitat in heavily used, infested areas (e.g., wooded recreation areas) by removing low brush and leaf litter. Tick infestations should be verified via tick flagging or dragging prior to habitat modification. Clearing should be done in low-risk months (i.e., November to February). 9. Prepare, as a contingency, to treat high-use areas with pesticides to decrease tick numbers if surveillance reveals high tick numbers and if nonchemical control techniques (e.g., brush removal, mowing, raking) do not provide adequate control. --- Trademark 3M is a registered trademark of Minnesota Mining and Manufacturing Co., St. Paul, MN 55133-3053