LYME DISEASE RISK ASSESSMENT, NAVAL WEAPONS STATION EARLE, COLTS NECK, NEW JERSEY, 21 DECEMBER 1991 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 (40-5) 08 APR 1992 LYME DISEASE RISK ASSESSMENT NO. 16-61-AK93-92 NAVAL WEAPONS STATION EARLE COLTS NECK, NEW JERSEY 21 DECEMBER 1991 1. REFERENCES. a. Lyme Disease Surveillance Summary, Vol. 3, No. 1, Centers for Disease Control, March 1992. b. Technical Information Memorandum No. 26, Lyme Disease: Vector Surveillance and Control. Armed Forces Pest Management Board, March 1990. c. AR 40-5, Preventive Medicine, 15 October 1990. 2. AUTHORITY. Section 335, Lyme Disease Research and Education Program, FY 92 Department of Defense Authorization Bill. 3. PURPOSE. To assess the risk of Lyme disease to Naval Weapons Station Earle (NWSE) personnel by examining white-tailed deer for the tick vector, Ixodes spp. and to assay collected ticks for the Lyme disease etiologic agent, Borrelia burgdorferi. 4. GENERAL. 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 the B. burgdorferi or antibodies to Lyme disease in the tick population or mammal host population respectively. Criteria for risk categorization follow: 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. Personnel Contacted. Mr. Thomas Gentile, Natural Resources Manager, NWSE. c. Survey Conduct. The field survey was conducted by CPT George Taylor, Environmental Science Officer, Preventive Medicine Service, U.S. Army Medical Department Activity, Fort Monmouth, New Jersey, on 21 December 1991. Ticks and whole blood collected were forwarded to this Activity. Serum samples were assayed via Indirect Fluorescent Antibody (IFA) tests by personnel of the U.S. Army Regional Veterinary Laboratory, Fort George G. Meade, Maryland for the presence of Lyme disease antibody. Ticks were identified and assayed, via Direct Fluorescent Antibody (DFA) tests by personnel of this Activity for the presence of B. burgdorferi. d. Technical Assistance. Technical assistance or further informal advice may be obtained by contacting the Entomological Sciences Division (ESD), this Activity, Commercial Phone 410-677-5281/6502 or DSN 923-5281/6502. 5. METHODS. a. Tick Collection. The head, ears, and necks of 8 of a total of 15 hunter-shot white-tailed deer (Odocoileus virginianus) were examined immediately before or after weigh-in and tagging at the NWSE deer check station. The deer hair was stroked contrary to the natural lay, using the hand to expose the skin. If no ticks were observed on the head, ears or neck of the animals examined, additional time was spent looking for ticks on other regions of the deer carcass. Seven of the 15 deer were not examined for ticks due to inadequate lighting. Total examination time-per-carcass was between 5 and 10 minutes. b. Blood Samples. Blood pooled in the body cavities of 15 hunter-shot deer was collected using clean plastic (4ml) disposable pipettes. Blood samples were not taken from carcasses that were rinsed with water or otherwise treated in a manner which might contaminate or invalidate the sample. Samples were placed in 7 ml labeled tubes, refrigerated and forwarded to this Activity, where they were spun, sera was collected, and frozen (-8.5 [degrees] C) until IFA testing could be performed. 6. RESULTS. (See also Enclosure 1) a. Deer Ticks, Ixodes dammini, were found on 7 of 8 deer examined for ticks. b. Eleven percent of 28 Deer Ticks, tested via DFA, were positive for the Lyme disease etiological agent, B. burgdorferi. c. One of two Winter Deer Ticks, Dermacentor albipictus, were positive for the Lyme disease etiological agent, B. burgdorferi. d. All serum samples tested from 15 deer were negative ([where positive equals] greater than 1:128 titer level) for the presence of antibody to Lyme disease. 7. DISCUSSION. Naval Weapons Station Earle has an established Lyme disease record. It ranks first in cases reported to the Office of the Army Surgeon General, among DOD installations listed as the source of human infection. For the five year period 1986-1990 approximately 115 cases were attributed to NWSE and the Fort Monmouth Wayside training area located at NWSE. The Centers for Disease Control also recognizes that there were additional unreported cases during that period. The area where NWSE is located is considered to be a hyper-endemic area for Lyme disease by Lyme disease professionals. In a previous survey conducted by this Activity in 1989 on host seeking Deer Ticks, 40 percent of 178 ticks tested were positive for B. burgdorferi. This is in keeping with expected tick infection rates in hyper-endemic areas. The unexpectedly low 13 percent tick infection rate and negative deer blood serology noted in this survey may be spurious and warrant continued surveillance in light of historical information. There is no corroborating evidence for New Jersey indicating a decreasing Lyme disease threat. The Centers for Disease Control reports 852 confirmed cases of Lyme disease for New Jersey in 1991. 8. CONCLUSION. The preponderance of information available indicates that the present risk of contracting Lyme disease at NWSE is high. The potential at-risk human population (those engaged in field training, natural resources activities etc.), along with availability of suitable animal hosts and environmental conditions, make NWSE an area warranting protective measures and continued vigilance. 9. RECOMMENDATIONS. The high risk category dictates the need for surveillance and immediate action. a. Implement programs and plans in accordance with guidelines of Enclosure 2. b. Conduct annual follow-up surveillance using the methods described in reference 1.b and para 5 above. Provide continued monitoring of the Lyme disease threat to NWSE personnel and timely implementation of preventive measures. [signature] THOMAS M. BURROUGHS CPT, MS Entomologist APPROVED BY: [signature] JAMES T. KARDATZKE, PhD, BCE MAJ, MS Chief, Entomological Sciences Division Enclosure 1 DOD LYME DISEASE SURVEY U.S. ARMY ENVIRONMENTAL HYGIENE ACTIVITY-NORTH DATA SUMMARY - FALL/WINTER 1991 INSTALLATION Naval Weapons Station Earle, New Jersey SURVEY DATE(S) 21 December 1991 # OF DEER EXAMINED (TOTAL) 15 # OF DEER EXAMINED FOR TICKS 8 # (%) DEER EXAMINED WITH Ixodes spp. 7 (88 percent) # DEER SERUM SAMPLES TESTED 15 # DEER SERUM SAMPLES POSITIVE * 0 TICK SPECIMENS ----------------------------------- # COLLECTED # TESTED # [%]POSITIVE Ixodes dammini ** 55 28 3 (11) Dermacentor albipictus 11 2 1 (50) Amblyomma americanum 0 0 0 --------------------------------- TOTAL TICKS 66 30 4 (13) * positive screening titer levels greater than 1:128 ** Ixodes dammini vs. Ixodes scapularis determination in adult ticks is difficult. However, random samples of adult specimens from installations as far south as Virginia and North Carolina were all identified as I. dammini by The Curator of Ticks, U.S. National Tick Collection, at the Institute of Arthropodology and Parasitology at Georgia Southern University. Enclosure 2 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-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-June and October-December). c. making available, for viewing, the video, LYME DISEASE: A growing threat (FAUPIN No. 504494DA). 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 George G. Meade, MD, 20755-5225. 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 and the 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 B. burgdorferi. Sampling should be performed in early summer when I. dammini nymphs (the life stage responsible for most human Lyme disease infections) are active. Post DA Poster 40-5 (or equivalent), and thereby 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. dammini. 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