LYME DISEASE RISK ASSESSMENT, BLOSSOM POINT TEST FACILITY, MARYLAND AND WOODBRIDGE RESEARCH FACILITY, VIRGINIA, 20 NOVEMBER - 6 DECEMBER 1993 DEPARTMENT OF THE ARMY U.S. Army Environmental Hygiene Activity - North Fort George G. Meade, Maryland 20755-5225 [Seal of Department of Defense, United States of America] REPLY TO ATTENTION OF: HSHB-AN-P (40-5f) 24 MAY 1994 LYME DISEASE RISK ASSESSMENT NO. 16-61-A2WX-94 BLOSSOM POINT TEST FACILITY, MARYLAND AND WOODBRIDGE RESEARCH FACILITY, VIRGINIA 20 NOVEMBER - 6 DECEMBER 1993 1. REFERENCES. See Appendix A. 2. AUTHORITY. AEHA Form 250-R, AMC, 10 October 1993. 3. PURPOSE. To assess the risk of Lyme disease to personnel of Blossom Point Field Test Facility (BPFTF), Maryland and Woodbridge Research Facility (WRF), Virginia by examining deer for the tick vector, Ixodes scapularis, and to assay ticks and deer blood for evidence of the Lyme disease etiologic agent, Borrelia burgdorferi, in accordance with AR 40-5, paragraph 10-7.f. Blossom Point Field Test Facility and WRF are located on opposite banks of the Patuxent River in Maryland and Virginia respectively and are both sub-installations of the U.S. Army Adelphi Laboratory Center (USAALC). Both facilities are addressed jointly in this report. 4. GENERAL. a. Risk Definition. The term "risk," as used in this report, is a non- statistical evaluation of qualitative and quantitative information on Lyme disease locally. To the extent available, information evaluated includes the following elements: (1) History of Lyme disease in the area (2) The presence of the tick vector (I. scapularis) and a host population needed to sustain a viable population of the vector (3) The presence of the Lyme disease-causing spirochete (B. burgdorferi)in the tick population (4) The presence of antibodies to B. burgdorferi in the mammalian host population Once gathered, this information was used to determine risk in the following manner: Low - Some elements of the Lyme disease cycle identified in nearby area, but not on the installation Moderate - Some elements of Lyme disease cycle identified from the installation or human cases of Lyme disease reported from the local area High - All elements of the Lyme disease cycle present on the installation b. Personnel Contacted. The purpose and methodology of this assessment were discussed with Mr. Robert Wardwell, Natural Resources Manager, USAALC. Mr. Wardwell coordinated the concurrent deer examinations at BPFTF and WRF. Ms. Ann Woodruff, Occupational Health Nurse, USAALC Health Clinic, was contacted for information on cases of human Lyme disease contracted on WRF and BPFTF. Dr. Jack Grigor, Maryland Public Health Veterinarian, Maryland Department of Health and Mental Hygiene (MDHMH), was contacted for information on cases of human Lyme disease in the State of Maryland. Ms. Nida Mickus, Secretary, Virginia Department of Health (VSDH), was contacted for information on cases of human Lyme disease in the State of Virginia. COL Lyman Roberts, Entomology Consultant, Department of the Army (DA), Office of The Surgeon General (OTSG), was contacted for information on reported cases of human Lyme disease from Army installations. c. Survey Conduct. Personnel from the USAALC conducted the deer examinations and collected tick and deer blood samples during the period 20 November to 6 December 1993. Ticks were identified and assayed via Direct Fluorescent Antibody (DFA) tests by personnel of this Activity. Serum samples were assayed via Indirect Fluorescent Antibody (IFA) tests by personnel of the U.S. Army Regional Veterinary Laboratory, Fort Sam Houston, Texas for the presence of antibodies to B. burgdorferi, the Lyme disease-causing spirochete. d. Technical Assistance. Technical assistance or further informal advice may be obtained by contacting Chief, Entomological Sciences Division, this Activity, commercial (301) 677-5281/6502 or DSN 923- 5281/6502. 5. BACKGROUND. a. Lyme disease is a multi-symptomatic infectious disease caused by the bacterial spirochete, B. burgdorferi, which is transmitted to humans by the bite of an infected tick. The disease is most often referred to as Lyme disease or Lyme arthritis in the United States. Lyme disease has become the most prevalent arthropod-borne illness in North America. Its geographic range is expanding and the number of reported cases continues to rise each year. b. The number of reported cases of Lyme disease received by the DA OTSG, however, has declined sharply over the past 5 years: Year (number of cases), 1989 (113); 1990 (70); 1991 (26); 1992 (14); 1993 (9). Public awareness and Lyme disease prevention programs may have contributed to a decline in the number of cases reported, but inconsistent reporting may be a more likely explanation. The lack of a rapid, reliable, and cost- effective diagnostic test for Lyme disease is a problem and can result in over- or under-reporting. The increased burden of reports on medical treatment facilities may also be a factor. Personnel concerned with Lyme disease prevention and control should not assume that human risk of Lyme disease has changed based on the number of reported cases alone. The need to protect soldiers and other personnel working on Army installations has increased with the documented spread of this disease. c. Epidemiological data for 1993 from the MDHMH revealed 207 confirmed cases of human Lyme disease in Maryland with 10 (5%) of these cases recorded from Charles County where BPFTF is located. In the same year the VSDH reported 95 confirmed cases of human Lyme disease in Virginia with 23 (24%) of these cases reported from Prince William County where WRF is located. The health clinic at USAALC reports no confirmed cases of human Lyme disease contracted at either BPFTF or WRF. d. At BPFTF from 30 November 1992 to 12 June 1993, deer and small mammals were examined for ticks and serum samples (from deer) were obtained. No ticks were collected on the deer examined, and all of the serum samples collected were negative for anitbodies to B. burgdorferi. However, 55 ticks were collected from small mammals (18 I. scapularis, and 37 Dermacentor variabilis). Seven of the 18 I. scapularis, and 1 of the 37 Dermacentor variabilis tested positive for B. burgdorferi (reference 7). e. At WRF from 21 November 1992 to 2 January 1993, 24 ticks were collected from deer (8 I. scapularis, 15 Dermacentor albipictus, and 1 Amblyomma americanum). All of the ticks tested negative for B. burgdorferi. However, four of 82 deer serum samples tested were positive for antibodies to B. burgdorferi (reference 8). f. At WRF from 23 November 1991 to 4 January 1992, 240 ticks were collected from deer (167 I. scapularis, 27 Dermacentor albipictus, and 46 Amblyomma americanum). Eleven of the I. scapularis, 3 Dermacentor albipictus, and 4 Amblyomma americanum tested positive for Borrelia spp. Four of 71 of the deer serum samples tested were positive for antibodies to B. burgdorferi (reference 9). 6. METHODS. a. Tick Collection. The head, neck, and ears of hunter-shot white-tailed deer (Odocoileus virginianus) were examined for the presence of ticks. Hair on deer was stroked against the natural lay, using the hand edge, to search for ticks. Ticks were removed using fine-point (No. 5) jeweler's forceps and returned to this Activity for identification and testing. Total examination time per carcass was approximately 5-10 minutes. b. Tick Testing. Collected ticks were tested via a two-phase DFA assay. Ticks were first tested using a polyclonal DFA procedure that tests for the presence of spirochetes belonging to the genus Borrelia. Ticks identified as containing these Borrelia spp. spirochetes were tested further by a species-specific DFA procedure to ascertain if the spirochetes were B. burgdorferi. c. Serum Testing. Blood pooled in the deer body cavities was collected using clean 4 ml diposable plastic pipettes. Samples were placed in 7 ml labeled tubes and spun for at least five minutes. The sera were separated and frozen (-9 degrees C) until IFA testing could be performed. 7. RESULTS. (Also see Appendices B and C) a. At BRFTF the Lyme disease etiologic agent B. burgdorferi was found in seven (19%) of the 37 Ixodes scapularis collected from deer examined. In addition seven (13%) of 56 deer serum samples tested positive (greater than 1:128 titer level) for antibodies to B. burgdorferi. b. All of the 6 D. albipictus and 12 A. americanum tested from BPFTF were negative for Borrelia spp. spirochetes. c. At WRF no ticks were collected from deer examined, however, six (16%) of 38 deer serum samples tested were positive (greater than 1:128 titer level) for antibodies to B. burgdorferi. 8. DISCUSSION. Results from this deer check station surveillance for ticks at BPFTF compare well with the results of the 1993 examination of live-captured small mammals at BPFTF (reference 8). Both surveys show all elements of the Lyme disease cycle present on or near BPFTF. The presence of Borrelia spp. spirochetes on WRF was first documented by this Activity in Lyme Disease Risk Assessment No. 16-61-A846-92 (reference 9). In this 1992 assessment, data indicated that the risk to WRF personnel was moderate. The tick vector of Lyme disease was not collected in the most recent survey, but there were confirmed cases of human Lyme disease reported from the local area in 1993. Historical evidence of human Lyme disease in the areas surrounding both BPFTF and WRF and conditions necessary for the occurrence of Lyme disease on both installations, place participants in outdoor and natural activities at risk for contracting Lyme disease at both BPFTF and WRF. Continued vigilance at these two installations is warranted. 9. CONCLUSIONS. The presence of B. burgdorferi positive I. scapularis on examined deer and current information from the MDHMH on the epidemiology of Lyme disease in the surrounding areas, indicate that the present risk of contracting human Lyme disease on BPFTF is HIGH. Historical evidence of Borrelia spp. positive I. scapularis, antibodies to Lyme disease from deer sampled at WRF and information from the VSDH indicate that the present risk of contracting human Lyme disease on WRF remains MODERATE. 10. RECOMMENDATIONS. a. Implement risk reduction measures in Appendix D. b. Make military, civilians, and family members aware of information on repellents contained in Appendices E and F. c. Assist this Activity in conducting biennial follow-up surveillance using the methods described in reference 3 and paragraph 6, above. d. Report all Lyme disease cases to the DA OTSG and to the Maryland and Virginia State Epidemiologists (AR 40-5, paragraph 3-2 and AR 40-400, paragraph 6-16). 11. ADDITIONAL ASSISTANCE. Additional direct support in the fields of pest management, pesticide risk management, water supply management, wastewater management, hazardous waste management, worksite hazards management, health care hazards management, ergonomic evaluation, sanitation and hygiene, and installation industrial hygiene management is available, and may be requested from USAEHA-North at DSN 923-6502/5281/6205, or commercial (301) 677-6502/5281/6205. (signature) MELISSA K. MILLER Entomologist Entomological Sciences Division APPENDIX A REFERENCES 1. AR 40-5, Preventive Medicine, 15 October 1990. 2. AR 40-400, Patient Administration, 1 November 1983. 3. Armed Forces Pest Management Board Technical Information Memorandum No. 26, Lyme Disease: Vector Surveillance and Control, March 1990. 4. Lyme Disease Surveillance Summary, Vol. 4, No. 3, Centers for Disease Control and Prevention, June 1993. 5. Oliver, J. H., et al. 1993. Conspecificity of Ticks Ixodes scapularis and I. dammini (Acari: Ixodidae). J. Med. Ent., 30:54-63. 6. Anderson, J. F. and L. Magnarelli. 1984. Avain and Mammalian Hosts for Spirochete-Infected Ticks and Insects in a Lyme Disease Focus in Connecticut. The Yale J. of Biol. and Med., 57:627-641. 7. Memorandum, USAEHA-North, HSHB-AN-P, 19 August 1993, subject: Lyme Disease Risk Assessment, No. 16-61-AW45-93, Woodbridge Research Facility, Virginia, 21 November 1992 to 2 January 1993. 8. Memorandum, USAEHA-North, HSHB-AN-P, 18 November 1993, subject: Lyme Disease Risk Assessment, No. 16-61-AY63-94, Blossom Point Field Test Facility, Maryland 30 November 1992 - 12 December 1992 and 26 May - 12 June 1993. 9. Memorandum, USAEHA-North, HSHB-AN-P, 22 July 1992, subject: Lyme Disease Risk Assessment, No. 16-61-A846-92, Woodbridge Research Facility, Virginia 23 and 30 November, 7, 14, 21, and 28 December 1991 and 4 January 1992. APPENDIX B DATA SUMMARY SHEET DOD LYME DISEASE SURVEY U.S. ARMY ENVIRONMENTAL HYGIENE ACTIVITY-NORTH BLOSSOM POINT FIELD TEST FACILITY, MARYLAND AND WOODBRIDGE RESEARCH FACILITY, VIRGINIA 20 NOVEMBER - 6 DECEMBER 1993 BLOSSOM POINT FIELD TEST FACILITY # DEER EXAMINED 58 # DEER SERUM SAMPLES TESTED 56 # HUMAN LYME DISEASE CASES, 1993 - CHARLES CO. 10 # HUMAN LYME DISEASE CASES, 1993 - MARYLAND 207 WOODBRIDGE RESEARCH FACILITY # DEER EXAMINED 43 # DEER SERUM SAMPLES TESTED 38 # HUMAN LYME DISEASE CASES, 1993 - PRINCE WILLIAM CO. 23 # HUMAN LYME DISEASE CASES, 1993 - VIRGINIA 95 ----------------------------------------------------------------------- APPENDIX C TICK TESTING (see footnote 1) AND SERUM TESTING (see footnote 2) RESULTS BLOSSOM POINT FIELD TEST FACILITY AND WOODBRIDGE RESEARCH FACILITY 20 NOVEMBER - 6 DECEMBER 1993 Table C-1. Ixodes scapularis collected from deer at Blossom Point Field Test Facility and tested for Borrelia species and Borrelia burgdorferi ========================================================================= Borrelia spp. B. burgdorferi ------------- -------------- #COLLECTED #TESTED # + % + #TESTED # + % + LARVAE 0 0 0 0 0 0 0 NYMPHS 0 0 0 0 0 0 0 FEMALES 20 20 4 20 4 4 100 MALES 19 17 3 18 3 3 100 ===== ===== ===== ===== ===== ===== ===== TOTAL 39 37 7 19 7 7 100 ------------------------------------------------------------------------- Table C-2. Dermacentor albipictus collected from deer at Blossom Point Field Test Facility and tested for Borrelia species and Borrelia burgdorferi ========================================================================= Borrelia spp. B. burgdorferi ------------- -------------- #COLLECTED #TESTED # + % + #TESTED # + % + LARVAE 0 0 0 0 0 0 0 NYMPHS 1 1 0 0 0 0 0 FEMALES 1 1 0 0 0 0 0 MALES 4 4 0 0 0 0 0 ===== ===== ===== ===== ===== ===== ===== TOTAL 6 6 0 0 0 0 0 ------------------------------------------------------------------------- Table C-3. Amblyomma americanum collected from deer at Blossom Point Field Test Facility and tested for Borrelia species and Borrelia burgdorferi ========================================================================= Borrelia spp. B. burgdorferi ------------- -------------- #COLLECTED #TESTED # + % + #TESTED # + % + LARVAE 0 0 0 0 0 0 0 NYMPHS 0 0 0 0 0 0 0 FEMALES 1 1 0 0 0 0 0 MALES 13 12 1 8 1 0 0 ===== ===== ===== ===== ===== ===== ===== TOTAL 14 13 1 8 1 0 0 ------------------------------------------------------------------------- Table C-4. SERUM SAMPLES collected at Blossom Point FIeld Test Facility 20 November to 6 December from 58 deer and tested for antibodies to Borrelia burgdorferi ========================================================================= Borrelia burgdorferi -------------------- #SAMPLES COLLECTED #TESTED # + % + TOTAL 56 56 7 13 ------------------------------------------------------------------------- Table C-5. SERUM SAMPLES collected at Woodbridge Research Facility 20 November to 6 December from 43 deer and tested for antibodies to Borrelia burgdorferi ========================================================================= Borrelia burgdorferi -------------------- #SAMPLES COLLECTED #TESTED # + % + TOTAL 43 38 6 16 ------------------------------------------------------------------------- 1 Direct Fluorescent Antibody (DFA) testing method 2 Indirect Fluorescent Antibody (IFA) testing method APPENDIX D Lyme Disease Risk Reduction Measures 1. Emphasize public awareness programs to educate troops, family members, civilian employees and visitors on personal protective measures and Lyme disease. Methods should include, but not be limited to: a. Distribution of printed Lyme disease handouts, such as tick identification cards (USAMD-7/89), pamphlets, and fact sheets. b. Notifications in the installation newsletter and post electronic media (e.g., closed-circuit TV), especially prior to the high-risk months (May-September). c. Making available, for viewing, videos "Lyme Disease: A growing threat" (FAUPIN No. 504494DD, Army TVT number 8-196) and "Application of the Arthropod Repellent System" (No. 708575, Army TVT number 8-232). 2. Submit any collected tick specimens (both field-collected or ticks that have been removed from individuals) alive for identification and DFA testing to USAEHA-North, Fort Meade, Maryland, 20755-5225. 3. Stock Permethrin Arthropod Repellent (NSN 6940-01-278-1336, 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 medical care 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 B. burgdorferi. Sampling should be performed in early summer when I. scapularis nymphs (the life stage responsible for most human Lyme disease infections) are active. Post DA Poster 40-5, to identify high risk areas. 6. Avoid high tick population areas for troop training or recreation. Such areas can be identified by tick dragging or flagging prior to use. Case by case surveillance is necessary due to the patchy distribution of I. scapularis. 7. 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., January and February). 8. 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 APPENDIX E REPELLENTS 1. Several arthropod repellents are available through the Defense General Supply Center (DGSC) or Self Service Supply System. When used in accordance with directions on the label and in conjunction with the proper wearing of clothing, 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 or commercial (804) 790-4865. Repellents available for use are described below: a. Insect/Arthropod Repellent Lotion (cream, 2 fluid ounces) for application to exposed skin. The lotion, NSN 6840-01-284-3982, 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 for a maximum of five weeks or five launderings. Apply more frequently if "buddy checks" reveal attached ticks. 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 55 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 (180 days in the field), 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, June 1991. 3. The Tick-Borne Diseases Card (GTA 8-5-56) is available from the Entomological Sciences Division, USAEHA-North, by calling DSN 923-5281 or commercial (301) 677-5281. APPENDIX F FACT SHEET - MOSQUITO AND TICK REPELLENTS * DEET (N,N-Diethyl-m-tolumide) containing repellents offer good protection against mosquitoes, and are formulated for application to exposed skin. * Permethrin containing repellents offer excellent protection against ticks, and are formulated for application to clothing. * DEET will also offer protection against ticks, keeping them from attaching to treated skin. However, ticks generally do not attach in exposed areas, the only areas DEET may be applied to. * Permethrin, on the other hand, will also offer protection against mosquitoes, but may not be applied to exposed skin where mosquitoes bite. It is useful for treating bed netting. * Combined use of DEET on exposed skin for mosquito repellency and Permethrin on clothing for tick repellency offers maximum protection against both pests. Always read and follow the label before using any compound. * Do not use tick and flea collars. A toxic reaction can result. Humans have sweat glands in their skin that serve as an avenue for chemical absorption. Dogs on the other hand, respire by panting, lacking sweat glands. In addition, pets have a thicker hair barrier than most humans to protect them from direct contact with the collars. * Various lotion products claim protection against mosquitoes. Professional literature both supports and refutes benefits from lotions. However, there is a consensus that mineral oil, a component of many lotions, does substantially reduce mosquito bites on treated skin. * Tests have shown that DEET products containing a high concentration (greater than 50%) of DEET do not offer greater protection than those products containing 30-50% DEET. * The following practices enhance the effectiveness of protection against mosquitoes and ticks when used in conjunction with repellents: - Cover as much exposed skin as possible. Consider loose fitting long- sleeved shirts in summer. - Tuck pants inside socks or boots to keep ticks out. - Wear light-colored clothing to make seeing ticks easier. - Plan ahead and treat clothing with permethrin before your outdoor activity begins. Permethrin binds with fabric and is persistent through several washings. - Store treated clothing in a plastic bag to help preserve repellent effectiveness and identify treated clothing.