Pest Management Special Study, Lyme Disease Vector Profile, Fort Polk, Louisiana, 16 - 23 November 1987 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-PMG Pest Management Special Study 16-44-0587-89 Lyme Disease Vector Profile Fort Polk, LA 16 - 23 November 1987 1. AUTHORITY. Memorandum, US Army Health Services Command, HSCL-P, 1 July 1987, subject: USAEHA Mission Services Support for HSC. 2. PURPOSE. To evaluate the current status of Lyme Disease at Fort Polk, LA, and to provide related educational support to installation personnel. 3. GENERAL. a. Personnel Contacted. See Appendix A, this report, for a list of personnel contacted. b. Briefings. An entrance briefing for COL Darland McCarty, Commander, USAMEDDAC Fort Polk, and COL Leeper, Deputy Commander for Clinical Services, was held on Wednesday, 18 November, at 0645 hours. In addition, the project officer made two Lyme Disease slide/lecture presentations: one to the medical staff at the Bayne Jones Community Hospital, and the other to the medical staff at the troop clinic. Information Fact Sheets on Lyme Disease were disseminated to the PVNTMED Service and to deer hunters at the Hunt Control Office. An interview was also provided to KPOK, Fort Polk Cable Television on Thursday, 19 November. c. Survey Personnel. This study was conducted during the period 16 - 23 November 1987 by the Project Officer, Ms. Sandra Evans, Biologist, and SP4 Lynne Johnson, Environmental Health Technician. Technical assistance was provided by CPT Richard Whittle, PVNTMED Svc, USAMEDDAC Fort Polk. 4. BACKGROUND. a. Education. (1) During the subject survey, the project officer made Lyme Disease slide/lecture presentations to the medical staffs of both the Bayne Jones Community Hospital and the troop clinic. This same educational show is available as a slide/cassette packet. Requests for a permanent copy of this Lyme Disease instructional packet can be made by writing or calling the Pest Management and Pesticide Monitoring Division, US Army Environmental Hygiene Agency, Aberdeen Proving Ground, MD 21010-5422, AUTOVON 584-3613/3015. It is envisioned that this slide presentation will be used to educate the widest possible range of personnel, to include physicians, physician assistants, nurses, occupational health professionals, veterinarians, and environmental, recreational services, and pest management personnel. (2) Information Fact Sheets on Lyme Disease were provided to the Fort Polk PVNTMED Services, and they were made available to deer hunters at the Hunt Control Office. A copy of the FACT SHEET is found in Appendix B. Such informational materials can be utilized to spread awareness of the potential for tick-borne disease, proper precautionary measures, the recognition of symptoms, and the importance of prompt medical attention. (3) It is especially important that the military medical community become familiar with the epidemiology, symptomatology, ecology, and control of Lyme Disease because of the possibility that troops will be exposed to infected ticks during field exercises, and because of the high mobility of military personnel. Education is the single most effective tool in conquering this treatable disease. b. Current Status of Lyme Disease. (1) To date, there have been no documented cases of Lyme Disease on Fort Polk. However, ticks infected with Borrelia burgdorferi have been found on other military installations, and soldiers, dependents, and civilian employees at those locations have become infected. Personnel exposed to infected ticks during outdoor occupational or recreational activities, or via contact with infested animals, may be at risk. (2) Troop strength at Fort Polk currently numbers approximately 15,400 with occasional, small upward fluctuations during summer training programs. Troop strength is projected to increase by several thousands by the year 2000. Troop activity during the summer months coincides with the period of greatest risk of exposure to ticks, and increases in troop strength will place more individuals in this category. (3) To date, the Louisiana Department of Health and Human Resources, has reported no confirmed cases of Lyme Disease for the state. However, in recent years, Lyme Disease has become the number one reported tick-borne disease in the U.S. In 1980, the Centers for Disease Control (CDC) in Atlanta, GA, reported 226 human cases of Lyme Disease nationwide, expanding to 1498 cases by 1984. Figures for 1985 and 1986 are 1520 and 1394, respectively. (ref 1) (4) It is suspected that numerous cases of Lyme Disease continue to go either unreported, undiagnosed, or misdiagnosed. This situation is due to a combination of factors, including the relatively recent notoriety of the disease, the variety and similarity of its symptoms to an assortment of other illnesses, lack of Federal and State reporting requirements, and lack of standardized Lyme Disease case criteria. (5) The recent requirement by the Army Office of the Surgeon General to report Lyme Disease on special telegraphic reports of selected conditions [RCS MED 16(R4)] has been an important step in identifying the scope of the Lyme Disease problem. (ref 2) Since clinical symptoms may be long-term and/or recurrent, this reporting system will be critical in tracking afflicted individuals as their duty stations change. It is important that both military and civilian personnel report to the occupational health clinic if they have a suspected or confirmed case of Lyme Disease which may have been acquired on the installation. (ref 3) c. History. (1) In 1979, the deer tick (Ixodes dammini) was described as the tick species responsible for spreading Lyme Disease. Since that time, it has been learned that the western black-legged tick, I. pacificus, is the primary vector for Lyme Disease in the western United States. Some evidence links a small number of cases of the disease to the Lone Star tick, Amblyomma americanum, and to the black-legged tick, I. scapularis, both abundant species across the southeastern U.S. In addition, laboratory tests show I. scapularis to be a competent vector of the Lyme Disease agent, Borrelia burgdorferi. (ref 4) (2) According to the literature and to surveys performed by this Agency to date, I. dammini have not been found farther south than Virginia. The present range of I. dammini appears to have expanded to its present extent over the past half century, concurrently with the increase of the white-tailed deer (Virgianus odicoileus) population. Its pattern of expansion resembles the migratory patterns of some birds. Parasitism and transport by birds appears to be an efficient mechanism for dispersion of immature I. dammini to areas currently uninfested. (refs 5,6) d. Methodology. The following methods were utilized to obtain samples from Fort Polk: collection of ticks and blood samples from mammal hosts (hunter-killed deer and wild hogs, and small mammals via trapping), and collection of questing ticks from the environment via tick walks. See Appendix C for a more thorough description of methods used for sample collection. 5. FINDINGS AND DISCUSSION. a. Small mammal surveillance. (1) One cotton rat, Sigmodon hispidus, was captured. A blood sample was obtained and careful combing was performed for ectoparasites. No ticks were observed. (2) As yet, there is no evidence that cotton rats are involved in the ecology of B. burgdorferi in the southern and southcentral United States. The white-footed mouse, Peromyscus leucopus, is the primiary host species for the immature stages of I. dammini in Lyme Disease-endemic areas of the country. Although conclusions cannot be drawn on the basis of a single mammal, the susceptibility of the cotton rat to B. burgdorferi and its role as a tick host should be considered in the spread of Lyme disease in southern and southcentral regions of this country. (ref 7) b. Deer Surveillance. (1) A total of 45 hunter-killed deer were presented for examination by survey personnel at the Hunt Control Office during the period 16 - 23 November, and to the Post Preventive Medicine Officer during the following week. (2) Blood samples were obtained from 14 of the deer. The remainder of the deer had either been gutted in the field or had been dead for too long to obtain an unclotted blood sample. (3) All 45 deer were examined for ectoparasites, and a total of 288 ticks were collected. Only 31 deer were infested with ticks. (4) Numbers of ticks per deer ranged from 0 to 33 for a mean of 9.3. (5) Subsequent tick identification revealed the following species: Ixodes scapularis - 287; and Amblyomma maculatum - 1. (6) To date, there has been no evidence to link A. maculatum with Lyme Disease. However, I. scapularis is very closely related to the known vector of Lyme Disease, I. dammini, and there has been some evidence linking it to transmission of the disease. (7) The white-tailed deer is the major host species for the adult stage of both I. dammini and I. scapularis. (8) Based upon an estimate by the installation wildlife biologist, the deer population at Fort Polk is 1 deer per 50 - 75 acres. This is considered a moderate population size for sandhill habitat, which characterizes the basic environment type at Fort Polk. However, a deer density of this size (8 -12 deer per square mile), is less than the average density of 20 deer per square mile in some endemic areas of the country for Lyme Disease. (ref 8) c. Tick Walk Surveillance. (1) Twelve sites, encompassing various habitat types and human usage patterns, were chosen for 30-meter walks. A listing of these site locations is presented in Appendix D. (2) No ticks were obtained during these walks. d. Hog Surveillance. (1) During the survey period, hunter-killed wild hogs were also presented to survey personnel at the Hunt Control Office. (2) A total of 6 hogs were examined for ectoparasites. Three of the hogs had 1 tick, while the remaining 3 had 0 ticks, for a mean of 0.5 tick/hog. All 3 ticks were I. scapularis. (3) Blood samples were obtained from each of the 6 hogs. e. Tick Analyses. (1) Only live ticks could be tested for parasite infection. Of 291 ticks collected from 31 deer and 3 wild hogs, only 144 I. scapularis were alive and could, therefore, be tested. (2) All tested ticks were negative for B. burgdorferi. (3) The high incidence of tick mortality was attributed to trauma sustained during removal from the host. I. scapularis, like I. dammini, has extremely long mouthparts, which when embedded in the skin of a host, are exceptionally difficult to remove intact. f. Blood Analyses. (1) All blood samples obtained during this survey were sent to the New York State Department of Health for analyses for antibody titers to B. burgdorferi. Results are currently pending, and upon receipt, will be transmitted in a follow-up report. (2) Antibody titers to B. burgdorferi will indicate whether or not these animals have been exposed to infected ticks. g. Habitat Assessement. (1) The predominant habitat type at Fort Polk is sandhill - pine/scrub oak. However, there are also significant areas of bottomland, hardwood environment. I. scapularis and I. dammini both prefer the higher humidity of this lusher habitat type, so they are more likely to be found freely questing in greater numbers in those areas. Therefore, human contact with Ixodes species may be reduced when activities are limited to drier areas. (2) Since host ranges widely transect habitat types, Ixodes will be present to some degree in most areas. Direct contact with host species, as well as with pets and other domestic animals which may transport these ticks into the home environment, increases the opportunity for human exposure. h. Personal Protection. (1) Avoidance of tick-infested areas is the most effective means of minimizing exposure to ticks. This may not be possible in many situations. (2) Proper wearing of the field uniform by blousing the pant leg into the boot, or tucking the pant legs into socks for civilians, forces ticks to crawl up the outside of clothing where they will more likely be noticed. This also reduces their access to the skin. Light colored clothing whenever possible also facilitates recognition of ticks. (3) Repellents are useful. Permethrin tick repellent, marketed under the tradename Permanone [Registered], has been registered in 26 states, to date, including Louisana. Currently, it is the most effective tick repellent available. It should not be applied to the skin. Studies are currently being conducted on the effectiveness of permethrin- impregnated battle dress uniforms. The repellent DEET can be applied to the skin, but does not afford the same degree of protection as permethrin- treated clothing. -------- [Registered]Permanone is a registered trademark of Fairfield American Corporation, Newark, NJ, and is distributed by Coulson International Corporation, Albany, NY. Use of trademarked name does not imply endorsement by the US Army, but is intended only to assist in identification of a specfic product. (4) Evidence suggests that ticks must be attached for a least 12 hours for transmission of Lyme Disease to occur. Therefore, frequent self and buddy checks when working in, and upon return from, the field are extremely important. (5) Ticks should be carefully removed from the skin as soon as they are detected. Grasping of the ticks mouthparts next to the skin with tweezers and pulling firmly and steadily is recommended. Squeezing or squashing of the tick should be avoided, and the wound site should be washed with antiseptic following removal. If an expanding rash or other symptoms present within a month of tick attachment, a physician's care should be sought immediately. g. Control Strategies. (1) Removal of the moist microclimate preferred by ticks by clearing underbrush and leaf litter, is one of the most effective means of reducing tick populations. Burning is often the most feasible means of obtaining the desired results over large scale areas. Mechanical removal of leaf litter and ground cover, and mowing of lawns, is recommended for residential/cantonment control. (ref 8) (2) Good deer herd management is recommended, although reduction of deer populations does not appear to dramatically affect the prevalence of Lyme Disease. Complete elimination of deer populations is neither feasible nor recommended. (ref 9, 10) (3) When alternative methods have failed to reduce tick exposure, pesticide applications may become necessary, especially for wide area tick control. (ref 11) One innovative and environmentally sound technique which appears to be very promising is the baited pesticide treatment tube method. (ref 12) In this method, the small mammal hosts remove permethrin-treated cotton from a carboard tube, and utilize it as nesting material. The immature stages of the ticks are then killed as the animals use their nests. 6. CONCLUSIONS. Although there have been no cases of Lyme Disease reported on Fort Polk to date, and current results do not indicate the presence of infected ticks, factors do exist which make the eventual spread of Lyme Disease into this area possible, i.e., a competent vector; and appropriate hosts, migratory mechanisms, and habitat. Increased troop activities on the installation during prime tick season increases the risk of exposure to ticks, and necessitates appropriate education, surveillance, and control and personal protection strategies. Reporting and data management mechanisms should be in place in the event that military or civilian cases of Lyme Disease begin to present. 7. RECOMMENDATIONS. All recommendations that do not list a specific authority are based on good pest management practices. a. Health Services Command, Fort Sam Houston, TX. Provide for reliable laboratory support for analyses of field-collected ticks. b. Preventive Medicine Service, USAMEDDAC, Fort Polk, LA. (1) Report all suspected or confirmed cases of Lyme Disease (or erythema chronicum migrans) by special telegraphic reports of selected conditions [RSC MED-16 (R4)] for all military personnel and civilian beneficiaries. (AR 40-400, paragraphs 6-1 through 6-3; Message, DASG-PSP- D, 191800Z Jun 87, subject: Lyme Disease Surveillance and Prevention) (2) Emphasize to all military and civilian personnel, the importance of reporting to the occupational health clinic if they have a suspected or confirmed case of Lyme Disease which may have been acquired on the installation. (3) Provide on-going education on Lyme Disease, other relevant tick- borne diseases, and tick-bite in general, to soldiers, dependents, civilian employees, and all other individuals with occupational or recreational exposure to ticks. Education should include recognition of symptoms, reporting requirements, treatment, tick removal technique, protective measures, and tick control, as appropriate. (AR 40-5, paragraph 2-2d) (4) Perform tick surveillance on a routine basis to determine tick species and tick infectivity rate. Base the frequency of surveillance efforts on previous surveillance results. [AR 40-5, paragraphs 10-3b(2) and 10-7b] c. Fort Polk, US Army Forces Command. (1) Assist the PVNTMED Svc by distributing approved educational materials on Lyme Disease, other relevant tick-borne diseases, and tick- bite in general, to those individuals who risk occupational and recreational exposure to ticks. (2) Initiate tick control as required based on results of surveillance. Perform pesticide applications only after appropriate non- chemical integrated pest management procedures (e.g., removal of underbrush and leaf litter, mowing, burning, repellents) have proven inadequate or impractical. [AR 40-5, paragraphs 10-4 and 14-3a(3)] (3) Consider stockage and usage of commercially available Permanone tick repellent, as necessary. (Message DASG-PSP-D, 191800Z Jun 87, subject: Lyme Disease Surveillance and Prevention; AR 40-5, paragraph 14- 2c) 8. REFERENCES. See Appendix E for a list of references. 9. TECHNICAL ASSISTANCE. Technical advice or consultation may be obtained by contacting the appropriate MACOM Pest Management Consultant. Informal technical advice or consultation regarding the findings and recommendations contained in this report may be obtained by calling the Entomological Sciences Division, US Army Environmental Hygiene Agency, AUTOVON 584- 3613/3015. Requests for services should be directed through appropriate channels of the requesting activity to Commander, US Army Environmental Hygiene Agency, ATTN: HSHB-MR-P, Aberdeen Proving Ground, MD 21010-5422, with an information copy furnished the Commander, US Army Health Services Command, ATTN: HSCL-P, Fort Sam Houston, TX 78234-6000. [signature] SANDRA R. EVANS Biologist Pest Management and Pesticide Monitoring Division APPROVED: [signature] A. LYNN HOCH MAJ, MS Chief, Pest Management Branch Pest Management and Pesticide Monitoring Division [signature] MARVIN A. LAWSON LTC, MS Chief, Pest Management and Pesticide Monitoring Division APPENDIX A PERSONNEL CONTACTED 1. Ms. D. Beal, Occupational Health Nurse, PVNTMED Service, Fort Polk 2. Mr. E. Herring, Chief Game Warden, Fort Polk 3. CPT C. Jones, Veterinary Service, Fort Polk 4. COL Leeper, Deputy Commander for Clinical Services, Fort Polk 5. COL D. McCarty, Commander, PVNTMED Service, Fort Polk 6. Dr. L. McFarland, Louisiana Department of Health and Human Resources 7. Mr. T. McKenna, Acting Chief Game Warden, Fort Polk 8. Mr. S. Paris, Wildlife Biologist, Fort Polk 9. MAJ Stikes, Division Surgeon, 5th Infantry Division, Fort Polk 10. CPT J. Taylor, D. O., Director, Continuing Medical Education, Fort Polk 11. CPT R. Whittle, Entomologist, PVNTMED Service, Fort Polk APPENDIX B FACT SHEET - LYME DISEASE Acknowledgement: This Fact Sheet is taken, in most part, from a Public Health Fact Sheet produced by the Massachusetts Department of Public Health. WHAT IS LYME DISEASE (LD)? Lyme Disease is an infectious disease syndrome that often begins with a characteristic rash, and which can later involve the joints, nervous system and/or heart. It is caused by a spiral-shaped bacteria called a spirochete that is transmitted to humans by the bite of an infected tick. WHERE IS LD FOUND? In 1975, an investigation of geographic clustering of children with arthritis in Lyme, Connecticut led to the description of this newly recognized disease. It is now apparent that LD occurs over wide areas of the United States. These areas correspond to the distribution of the known tick species that carry the disease. Currently, the major affected areas are the Northeast from Massachusetts to Maryland, the Midwest in Wisconsin and Minnesota, and the West in California and Oregon. Cases have been reported in other states, however, as well as in Europe, Asia, and Australia. HOW IS LD TRANSMITTED? In the Northeast and Midwest, the "deer tick" or "bear tick" (known by the scientific name, Ixodes dammini), and in the West, the western black-legged tick (Ixodes pacificus), are the known tick transmitters (or vectors) for the disease. In either case, the tick is very small (i.e., much smaller than the well known dog tick, Dermacentor variabilis, or the Lone Star tick, Amblyomma americanum), and the immature stages are no larger than the period on a printed page. It is currently unclear whether other ticks may be involved in transmission of LD. The ticks cling to vegetation and are most numerous in a brushy, wooded, or grassy habitat. The tick's two year life cycle requires that the tick feed (takes a blood meal) on three separate hosts. These hosts include a variety of animals, including birds, but white-footed mice and deer are preferred. The spirochete that causes LD, Borrelia burgdorferi, is acquired by juvenile ticks (larvae) that feed on an infected animal, usually a mouse. The next juvenile stage of the tick (nymph), attaches to vegetation and is transferred by direct contact to the skin of a passing animal or human. The bite of the infected nymphal tick can then transmit the infectious organism to the new host. Thus, the greatest chance of becoming infected by the bite of the tick occurs while walking barelegged through brush or tall grass during May through August, the period of greatest nymphal tick activity in most areas. The adult tick feeds mainly on deer but may also become attached to, and infect humans. It is important to remember that not all ticks carry Lyme Disease. Thus, a tick bite does not necessarily mean that disease will follow, and prompt removal of a tick will lessen any chance of disease transmission. WHAT ARE THE SYMPTOMS? Early - The first symptoms of LD is usually a skin rash, called erythema chronicum migrans (ECM), that occurs at the site of the tick bite. The actual tick may go unrecognized. The rash, which begins 2 to 32 days after the tick bite, begins as a small red area which gradually enlarges, often with partial clearing in the center of the lesion so that it resembles a donut or bulls-eye. There may be multiple secondary lesions. The skin lesion is occasionally described as burning or itching. A small number of people with LD may not have the early skin rash, and symptoms may appear only in the later stages of the disease. Other skin signs include hives, redness of the cheeks and under the eyes (malar rash), and/or swelling of the eyelids with reddening of whites of the eyes. These skin signs may be accompanied by flu-like symptoms such as fever, headache, stiff neck, sore and aching muscles and joints, fatigue, sore throat and swollen glands. If not treated, these symptoms may disappear on their own over a period of weeks; however, the rash may recur in about 50% of untreated people, and more serious problems may follow later. If treated with appropriate antibiotics, the skin rash goes away within days, and complications may be avoided. Late - There are three major organ systems involved in later stages of the disease - the joints, the nervous system, and the heart. These can become affected weeks to months after the initial symptoms, although symptoms typically appear 4 to 6 weeks after the initial tick bite. Symptoms in the joints occur in up to 60% of untreated persons. This is an arthritis affecting the large joints, primarily the knee, elbow and wrist, which can move from joint-to-joint, and can become chronic. Neurologic complications occur in 10-20% of infected persons. The most common symptoms include severe headache and stiff neck (asceptic meningitis), facial paralysis (or other cranial nerve palsies), and weakness and/or pain of the chest or extremities (radiculoneuritis). These symptoms can persist for weeks, often fluctuate in severity, and may respond to intravenous antibiotics. Heart symptoms occur in 6-10% of infected persons. The electrical conduction in the heart may be affected and an inflammation of the heart muscle (myocarditis), or heart block may occur. HOW IS LD DIAGNOSED? Diagnosis is based primarily on recognition of the typical symptoms of LD such as the characteristic skin rash occurring in a person who lives in or has visited one of the areas mentioned earlier. PROMPT TREATMENT OF EARLY SYMPTOMS MAY PREVENT LATER AND MORE SERIOUS PROBLEMS. Atypical cases, or cases presenting with only later stage complications, are difficult to diagnose. In these persons, a blood test looking for antibody to the causative bacteria is often helpful. It should be noted that early in the disease, this blood test can be negative even though disease is present; only with later disease does the test become reliably positive. WHAT IS THE TREATMENT? Oral antibiotic treatment is beneficial early in the illness and often prevents late complications. Tetracycline appears to be the most effective drug. In children under 7 years, penicillin is the drug of choice (tetracycline can stain the enamel of developing teeth in children). In penicillin-allergic persons, erythromycin can be substituted, although it may be less effective. HOW CAN LD BE PREVENTED? The only known way to get LD is from a bite from an infectious tick. Knowldege of where these ticks are found, avoidance of such areas, and, if bitten, prompt removal of the tick, are the primary preventive measures. Persons living in areas where ticks are prevalent, particularly if the known tick vector species is present, should be aware of the following preventive measures: Don't walk barelegged in tall grass, scrubby areas or woods where the ticks may be found. If you do walk in such areas, wear a long-sleeved shirt, long pants, and high socks (with pants tucked tightly into the socks). Light colors will help the recognition of the tick on clothing. Conduct daily "tick checks". The ticks are most often found on the thigh, flank, arms, underarms, and legs, and are very small. Look for new "freckles". To remove a tick, use tweezers to firmly grip the tick's mouthparts as close to the skin as possible, and pull it straight outward. If using fingers, place a protective covering between your fingers and the tick, and wash your hands afterward. Apply an antiseptic to the bitten area. After removing, destroy the tick by immersing it in alcohol. Save the tick in the event that symptoms arise and identification of the tick becomes necessary. Be aware of the symptoms of Lyme Disease. IF YOU HAVE BEEN IN AN AREA WHERE THE TICK IS FOUND AND YOU DEVELOP SUCH SYMPTOMS, PARTICULARLY THE SKIN RASH AND/OR 'FLU' SYMPTOMS DURING THE PERIOD FROM MAY THROUGHOUT EARLY FALL, YOU SHOULD PROMPTLY SEE A PHYSICIAN FOR EVALUATION AND TREATMENT. APPENDIX C METHODOLOGY FOR THE COLLECTION OF TICKS FORT POLK, LA, 16 - 23 NOVEMBER 1987 1. Small Mammal Trapping. a. Three areas were selected for study. An attempt was made to choose locations which would be representative of major habitat types on the installation, and which would also coincide with high levels of human activity. (1) Trapping Site 1 was located immediately adjacent to the north end of Alligator Lake approximately at map grid coordinates 15RVE855456. The site was characterized as a drainage area of scrub and tangled, mixed hardwoods, with a dense understory of blackberry and grasses. (2) Trapping Site 2 was an oldfield habitat of high grasses located through a powerline cut at the junction of Old Creek Road and Mississippi Avenue. The approximate map grid coordinates of the area were 15RVE807382. (3) Trapping Site 3 was located off Route 467 approximately at map grid coordinates 15RVE778386. The area was a mixed hardwood habitat of hickory, maple, sweetgum, and pines, with moderate understory. b. Two perpendicular, transecting trap lines were arranged at each site. Ten 9 inch X 3.5 inch X 3 inch Sherman live traps were placed on each trap line at 15 meter intervals, for a total of 20 traps per site. c. Traps were baited in the evening with a moist mixture of oatmeal and peanut butter, and checked in the morning for trap success. Trapping was performed for two nights, non-consecutively due to scheduling constraints. 2. Deer Surveillance. a. During the survey period, as well as the following week, deer hunters on Fort Polk cooperated with the request to present any deer they killed to the survey team for 15-20 minutes. Deer were brought to the Hunt Control Office for examination. b. A total of 45 deer were processed over the two-week period. Blood samples were obtained either by intra-cardiac puncture, or by pipetting blood directly from the heart during the gutting process. Deer were examined for ectoparasites. c. Ticks removed from the deer were a reasonable estimate of the total number of ticks present on the animals. In most cases, all observed ticks were removed in the allotted time. 3. Tick Walks. a. Twelve sites were chosen for tick walks. The selections were based upon the same criteria as those for mammal trapping locations, i.e., major habitat types and human usage. A listing of these sites is presented in Appendix E. b. Clothing worn for a tick walk consisted of long sleeve, white cotton coveralls, with pant legs tucked into high white socks, and low cut, white tennis shoes. This uniform would provide the greatest possible surface area for questing ticks to cling to. The light color would make it easier to spot ticks. c. One tick walk was performed at each selected site. Each walk consisted of a total of 30 meters walked in an equilateral triangle pattern, 10 meters on a side, so that the starting point and the ending point were the same. 4. Hog Surveillance. There is a large population of wild hogs on Fort Polk. Currently, there is no available literature on the role that wild hogs may or may not play in the ecology of Lyme Disease. Since hunters also presented these animals to survey personnel during the study period, and since time permitted, blood samples were drawn from all six hunter- killed hogs by intra-cardiac puncture. They were also combed for ectoparasites. All observed ticks were removed. APPENDIX D TICK WALKS, FORT POLK, LA, 16 - 23 NOVEMBER 1987 Sample Grid No. Date Coordinates Location Habitat Description 01 11/17 15RVE778386 Wooded area off Lowland, hardwood Route 467 02 11/17 15RVE855456 Alligator Lake, Marshy, very dense Recreation Area tangle of scrub and grasses 03 11/17 15RVE807382 Power cut line High grass off Mississippi Ave 04 11/21 15RVE855447 Alligator Lake, Boy Mixed hardwood/pine, Scout Camp sparse understory 05 11/21 15RVE856448 Alligator Lake, Boy High grass, weeds, Scout Camp shrubs 06 11/21 15RVE853445 Alligator Lake, Boy Minor timber cuts, Scout Camp high grass, weeds, scrub trees 07 11/21 15RVE843430 Cantonment by Bldg Mixed hardwood/pine 8230 on 14th St 08 11/21 15RVE816414 Residential, corner Woodland edge, high of Entrance Rd and grass and weeds Chaffee Ave 09 11/21 15RVE799364 Residential, HQ, 5th Lowland scrub, dense Signal Bn, Mississ- vines, grasses, and sippi Ave and 4th St willows 10 11/21 15RVE787365 Residential, Wood- Lowland woodland, land Park Enlisted mixed hardwood/pine, Housing, Bellrichard dense understory Ave and Reed Ct 11 11/21 15RVE789369 Residential, Dogwood Mixed hardwood/pine, Ter, end of Ellis Ct moderate understory of across Rte 467 from blueberry hospital 12 11/21 15RVE795328 Residential, off Rte Mixed hardwood/pine, 10, just past inter- dense understory of section with Missis- blueberry and scrub sippi Ave APPENDIX E REFERENCES 1. Personal communication with Dr. Patrick Moore, Centers for Disease Control, Atlanta, GA, 21 January 1988. 2. Message, DASG-PSP-D, 191800Z Jun 87, subject: Lyme Disease Surveillance and Prevention. 3. Smith, Perry F., Benach, Jorge L., White, Dennis J., Stroup, Donna F., and Morse, Dale L. Lyme Disease - Occupational Risk in Endemic Areas. International Conference on Lyme Disease and Related Disorders. 14 - 16 September 1987. New York, NY. 4. Piesman, Joseph. Vector Competence of Ticks in the Southeastern United States for Borrelia burgdorferi. International Conference on Lyme Disease and Related Disorders. 14 - 16 September 1987. New York, NY. 5. Habicht, Gail S., Beck, Gregory, and Benach, Jorge L. Lyme Disease. Scientific American. May, 1987. 6. Anderson, John F., and Magnarelli, Louis A. Avian and Mammalian Hosts for Spirochete-Infected Ticks and Insects in a Lyme Disease Focus in Connecticut. Yale J. of Bio. and Med., Inc.: 627 - 641. 1984. 7. Burgdorfer, Willy, and Gage, Kenneth L. Susceptibility of the Hispid Cotton Rat (Sigmodon hispidus) to the Lyme Disease Spirochete (Borrelia burgdorferi). Am. J. Trop. Med. Hyg. 37(3): 624 - 628. 1987. 8. Schultze, Terry L., Lakat, Michael F., Bowen, Stephen, Parkin, William E., and Shisler, Joseph K. Ixodes dammini (Acari: Ixodidae) and Other Ixodid Ticks Collected From White-Tailed Deer in New Jersey, USA. J. Med. Entomol. 21(6): 741 - 749. 29 November 1984. 9. Wilson, Mark L. Reduced Abundance of Adult Ixodes dammini (Acari: Ixodidae) Following Destruction of Vegetation. J. of Econ. Entomol. 79(3): 693 - 696. June 1986. 10. Wilson, Mark L., Levine, Jay F., and Spielman, Andrew. Effect of Deer Reduction on Abundance of the Deer Tick (Ixodes dammini), Yale J. of Bio. and Med., Inc.: 697 - 705. 1984. 11. Wilson, Mark, Litvin, Thomas, and Gavin, Thomas. Microgeographic Distribution of Deer and Ixodes dammini: Options for Reducing the Risk of Lyme Disease. 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