PEST MANAGEMENT CONSULTATION, CAMP SHELBY, HATTIESBURG, MISSISSIPPI, 24-28 APRIL 1989 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-EMG 19 FEB 1991 PEST MANAGEMENT CONSULTATION NO. 16-44-0519-91 CAMP SHELBY, HATTIESBURG, MISSISSIPPI 24-28 APRIL 1989 1. REFERENCES. a. AR 40-5, 15 October 1990, Preventive Medicine. b. AR 40-400, 1 October 1983, Patient Administration. c. AR 420-76, 3 June 1986, Pest Management. 2. AUTHORITY. a. Memorandum, HSC, HSCL-P, 10 February 1988, subject: Lyme Disease on Army Installations, Project No. 16-44-0519-91. b. Telephone conversation between 1LT David Smith, for MAJ Robert Lee, Environmental Management Specialist, Office of the Mississippi Adjutant General and CPT George W. Korch, Jr, U.S. Army Environmental Hygiene Agency (USAEHA). 3. PURPOSE. a. To characterize the spatial distribution and relative frequency of the black legged tick, Ixodes scapularis, and other tick vectors of disease on Camp Shelby as determined by drag cloth survey and infestation on small mammals. b. To determine the prevalence of infection of indigenous tick species with the Lyme disease (LD) agent, Borrelia burgdorferi. c. To assess the prevalence of specific antibody to B. burgdorferi in the small mammal population. d. To evaluate the potential exposure of personnel at Camp Shelby to LD, and offer recommendations on tick surveillance, tick control, and control of human exposure to LD. e. To gather information on possible human cases of LD on the installation. 4. GENERAL. a. Personnel Contacted. See Appendix A for a list of personnel contacted and/or briefed. b. Survey Conduct. The survey was conducted by CPT George W. Korch, Entomologist, Entomological Sciences Division, USAEHA, APG, MD; Dr. Peter J. Egan, Entomologist, and SSG Cheryl A. Whittern, Preventive Medicine Technician, USAEHA-South, Fort McPherson, Georgia, 24-28 April 1989. Additional assistance was provided to the survey team by personnel from the Facilities Engineering Division, Camp Shelby, Mississippi. c. Background. (1) Camp Shelby is a training site maintained by the Mississippi National Guard (MNG). The installation is approximately 62,350 hectares, of which 88 percent is land granted to the MNG by special use permit through the U.S. Forest Service. The remaining area is either owned by the State (6 percent), by the U.S. Army (1 percent), or leased from private owners (5 percent). The installation is 16 km south of Hattiesburg, Mississippi and occupies the northern border of the DeSoto National Forest. (2) The topography is generally composed of rolling hills, which grade from higher elevation (115 m) to lower (20 m) elevation along a northwest to southeast axis. The major drainage occurs east of the installation via the Leaf River. There are no major surface water features on the installation; however, there are numerous small streams and several ponds interspersed throughout the site. The soil ranges from sandy in the higher elevations, to clay sand mix in bottomland. (3) The vegetation is mixed deciduous and coniferous forest. Southern long-leaf pine, loblolly pine, and black jack oak are the predominant coniferous species and occupy the drier high areas, while sweet gum, magnolia, tulip poplar, red maple, and other deciduous hardwoods occur in stands along stream-side or bottomland habitats. (4) The cantonment area is located in the northwest corner of the installation, and the main impact area lies 12 km to the southeast. There are over 50 ranges, 92 artillery firing points and 64 training areas capable of supporting up to seven artillery battalions simultaneously. In addition, there are six tank firing ranges, including an M-1 tank range, and numerous infantry firing points. (5) The installation employs 722 full time workers who are responsible for the administrative operations or staff the tenant organizations. The tenant organizations include the Mississippi Military Academy, the Region III Noncommissioned Officer's Academy, the Regional Maintenance Training Site, the DEPMEDS training office, and the 60 M A2 training school. This site is designated by FORSCOM as a major station for overseas deployment during mobilization. (6) Camp Shelby cumulatively provides annual and weekend training for up to 109,000 Army National Guardsmen and Reservists from a wide geographic area, generally comprising the southeastern United States. The installation experienced a steady rise in usage over the last few years, due to its hospitable climate, general lack of environmental constraints on firing exercises, and cost factors. Camp Shelby has hosted units from Puerto Rico, Wisconsin, and New Jersey. Training activities are scheduled year round with the exception of mid-December through mid-January. (7) Installation medical services are limited to two small clinics. Visiting organizations must provide organic medical assets during training. Medical care for permanent party, or individuals on TDY for training status is supplied either through agreement with local providers, or through Keesler Air Force Base, Preventive Medicine support for the installation comes under the jurisdiction of the Fort Polk MEDDAC, but there are no Preventive Medicine personnel assigned permanently. (8) There were six cases of Lyme disease reported as locally acquired within Mississippi during 1988, and a similar number of cases reported in 1989 and 1990. These cases were widely scattered throughout the State. Lyme disease was not a reportable disease in the State of Mississipi at the time of this survey. (9) Lyme disease is a bacterial disease transmitted to man and animals via the bite of an infective tick. A synopsis of this disease and its transmission cycle is presented in Appendix B. 5. FINDINGS AND DISCUSSION. a. Lyme Disease Surveillance, Occurrence and Practices to Date. (1) There is no evidence for Lyme disease on Camp Shelby, Mississippi. SFC Lott offered anecdotal information of a case of diagnosed Lyme disease occurring in February 1989 in a relative (nephew) living in Beaumont. This town lies along the northeastern boundary of the installation. The case could not be confirmed through the local office of the State Department of Health. (2) There is no Lyme disease surveillance program currently in place on the installation due to the presumed low risk of LD exposure and the lack of organic Preventive Medicine expertise. (3) There were no statistics available on the population density of the white-tailed deer on the installation. White-tailed deer abundance is generally positively correlated with density of the tick. (4) The game warden indicated that the deer population was generally much higher in the cantonment area, due to the lack of hunting pressure in this area. Hunting is allowed on the remaining area of the installation; however, no information was available on the number of deer removed during hunting season. Hunters are allowed a five deer limit with no conditions placed on the size or condition of the deer. (5) The Camp Shelby deer hunting program is loosely structured and with no hunter check-out procedure, which would make it difficult to obtain tick and serum samples from deer carcasses. Ticks collected in this manner can be used to estimate prevalence rate of B. burgdorferi; sera are used to assess exposure of the deer to the spirochete. (6) Installation personnel view the level and frequency of tick- related problems as minimal. Peak levels of tick infestation usually occur in mid-summer, and are typically due to the American dog tick, Dermacentor variabilis, or the Lone star tick, Amblyomma americanum. This period does not coincide with the activity period of adult (mid-autumn to spring), or nymphal (spring-early summer) Ixodes scapularis. However, the game warden did report finding adult black-legged ticks on his clothing during the winter. b. Lyme Disease Health Information. (1) The survey officer delivered a 40-minute briefing on Lyme disease, which was attended by approximately twenty installation personnel. (2) The Lyme disease slide program produced by USAEHA, was sent to the Facility Engineering Division for future use in training installation personnel, or for visiting units concerning symptoms, natural history, and personal protective measures to safeguard against this infectious agent. c. Tick and Serum Collection Activities. (1) Two small-mammal trapping sites were established to obtain tick specimens and serum samples; the first site was located in the vicinity of the land navigation course, due north of Lee Street at 12th Street (BK886540). The second site was located 2 km east of the cantonment area due south of Lee Street (BK966537). Fifty traps were placed per site, and operated for two nights (200 trapnights). One cotton mouse (Peromyscus gossypinus) was captured at site 1, and five cotton mice at site 2. Serum samples were collected from each mouse, and two ticks (Dermacentor variabilis) were removed from a mouse captured at site 2. (2) Vegetation was dragged for ticks at 17 sites to obtain a representative sampling of the entire installation (Appendix C, Table 1). Efforts were concentrated in favorable tick habitat in areas frequently used for training. Thirty-eight ticks were collected during 5800 m of dragging: 3 adult Ixodes scapularis (black-legged tick), 4 adult Dermacentor variabilis (American dog tick), and 31 nymphal and adult Amblyomma americanum (lone star tick). d. Analysis of Prevalence of Infection. (1) None of the mice were seropositive for B. burgdorferi by immunofluorescent antibody testing performed at USAEHA. (2) None of the ticks were positive for B. burgdorferi as indicated by immunofluorescent antibody testing (Appendix C, Table 2). 6. CONCLUSIONS. a. The risk of personnel exposure to Lyme disease on Camp Shelby appears to be low. The tick vector for Lyme disease in Mississippi, Ixodes scapularis, was found in limited number and only at 2/17 sites surveyed. The lone star tick, Amblyomma americanum was the primary species recovered during our sampling. No evidence was found of Lyme disease on Camp Shelby based on collection and analysis of tick and small mammal tissues, and upon consultation with State health department personnel. b. The incidence of Lyme disease in the southeastern United States may be rising. Georgia reported a dramatic rise in the number of cases of disease acquired within state during the period 1989 to 1990. While much of the increase may reflect heightened medical awareness and diagnosis, the causative agent is also likely spreading from the major northeastern focus of the disease. Therefore, continued surveillance for Lyme disease is needed. 7. RECOMMENDATIONS. a. Provide continuing training for installation personnel about Lyme disease symptoms and prevention. Training aids now include a 15-minute video tape about the disease, wallet-sized tick and disease identification cards, the Lyme disease slide program, and DA warning posters (DA Form 40- 5). These materials are available from the Fort Polk MEDDAC. b. Provide information to commanders of visiting training units concerning personal protective measures to prevent tick-borne diseases (such as that presented in Appendix D). c. Monitor the Mississippi Health Department reports for evidence of local cases of Lyme disease. d. Report all diagnosed cases of Lyme disease to the Office of the Surgeon General under Report of Selected Conditions (AR 40-400). 8. TECHNICAL ASSISTANCE. Requests for services should be directed through appropriate command channels of the requesting activity to Commander, U.S. Army Environmental Hygiene Agency, ATTN: HSHB-MR-E, Aberdeen Proving Ground, MD 21010-5422, with an information copy furnished the Commander, U.S. Army Health Services Command, ATTN: HSCL-P, Fort Sam Houston, TX 78234-6000. [signature of Richard D. Wells] for GEORGE W. KORCH, JR CPT, MS Entomological Sciences Division APPROVED: [signature] RICHARD D. WELLS Program Manager, Pest Management Entomological Sciences Division APPENDIX A PERSONNEL CONTACTED 1. MAJ David Stewart, Operations and Training Officer, Camp Shelby, MS, MSNG. 2. CPT Michael Dewease, Game Warden, Camp Shelby, MS, MSNG. 3. SFC Glen Lott, Facilities Engineering Division, Camp Shelby, MS, MSNG. 4. SSG Lee, Facilities Engineering Division, Camp Shelby, MS, MSNG. 5. Dr. Jerome Goddard, Entomologist, Mississippi State Department of Health, Jackson, MS. 6. Ms. R. Keene, District VIII, Mississippi State Department of Health, Hattiesburg, MS. APPENDIX B GENERAL LYME DISEASE INFORMATION Lyme disease is a multi-systemic bacterial disease which is transmitted to man generally via the bite of an infected tick. The disease progresses from an early stage involving a rash, malaise, fever and several other general symptoms to a secondary stage characterized by neurologic, or cardiologic abnormalities. Intermittent or transient arthritis and chronic debilitating neurologic disturbance are typically seen in the third stage of illness and can last months to years in duration. Not all patients present the entire range of symptoms. Many individuals apparently become asymptomatic, although it is not clear whether this necessarily indicates elimination of the causative organism from the patient. Serological findings are used to corrobarate clinical evidence of disease but should not be relied upon as diagnostic of Lyme disease. Early antibiotic therapy is effective in reducing likelihood of further symptoms, although failures to alleviate symptoms with antibiotic therapy have been reported. Tetracycline and its derivatives are the current drugs of choice in treatment. In Mississippi, the tick species primarily responsible for Lyme disease transmission to humans is the Black-legged tick, Ixodes scapularis. The spirochete resides in the midgut of tick, and is transmitted to a mammal (or avian) host via the tick's salivary secretions during ingestion of a blood meal. Mice of the genus Peromyscus (deer mice) are particularly important hosts for the subadult tick stages (larvae and nymphs), and participates in the natural transmission cycle of the spirochete. This tick however feeds on a wide variety of birds, mammals, and reptiles. While studies have shown that birds are capable of transmitting spirochetes to engorging ticks, lizards are thought to be refractory to infection. The presence of larger reptile populations in the southeastern United States, compared to the northeastern states, is thought to result in a reduced Borrelia burgdorferi infection rate in the tick vectors since the large numbers of ticks feeding on reptiles would not acquire infection. The life history of the black-legged begins with the larvae which are active from mid-summer to early autumn, feeding on a wide variety of terrestrial vertebrate hosts. Successfully fed larvae molt to become the second stage, or nymphal ticks, which feed the next spring season. This life stage also has a wide host range. The nymph molts to the adult life stage which complete their life cycle feeding on deer and other large mammals in the autumn through mid-spring. The ticks become infected either [sic] while feeding on their small mammal hosts. While deer support the adult tick population, and provide an opportunity for mating, and dispersal of gravid females they probably do not play an important role as far as transmitting infection to the ticks. The black-legged tick is most likely to be encountered in cooler, wooded settings, with moderate to dense understory. The nymph measures only 1.2 mm in length and is dark brown to black in color, making it difficult to see on military field uniforms. Frequent inspection of the garments for ticks while in the field is necessary to prevent later tick attachment. Attached ticks must be removed as soon as possible, using tweezers to grasp the tick at the skin surface and gently pull away from the skin. Use of repellents such as DEET provide only limited protection against tick attachment. The clothing based permethrin repellents administered as a 0.5 percent aerosol spray provide a very high level of repellency (due to toxic effect against ticks). APPENDIX C TABLE 1. SUMMARY OF TICKS COLLECTED BY DRAGGING METHOD PERFORMED AT CAMP SHELBY, MS, 25-27 APR 89 [Data omitted - data summarized in above report] TABLE 2. SUMMARY OF TICKS COLLECTED AT CAMP SHELBY AND TESTED FOR Borrelia burgdorferi INFECTION BY THE IMMUNOFLUORESCENT ANTIBODY TECHNIQUE (IFA) [Data omitted - data summarized in above report] APPENDIX D U.S. Army Environmental Hygiene Agency Entomological Sciences Division [picture of tick] Aberdeen Proving Ground, MD 21010-5422 FACT SHEET - PROTECTION FROM TICKS AND LYME DISEASE WHAT IT'S ALL ABOUT Soldiers and other personnel and dependents who live, train, work, or play in the field, share their environment with many forms of animal and insect life. Ticks may be abundant in both wooded and grassy areas. Several tick species are vectors or "transmitters" of Lyme disease. They include the deer tick, Ixodes dammini, in the Northeast and Midwest, and the western black-legged tick, Ixodes pacificus, in the West. Two other species, the Lone Star tick, Amblyomma americanum, and the black-legged tick, Ixodes scapularis, are prevalent across the South, and are potential vectors of Lyme disease. BE CONCERNED - BUT NOT ALARMED. Not all ticks carry Lyme disease, so a tick bite does not necessarily mean that disease will follow. In addition, prompt removal of a tick will lessen the chance of disease transmission. BUDDY UP When in the field, buddy up and routinely check for ticks every few hours or as frequently as possible. After returning indoors, remove your clothing and check your body carefully. Pay special attention to the hairy and/or warm, moist parts of the body. You can greatly reduce your chance of tick bite by following the DOD REPELLENT SYSTEM of wearing proper clothing and using both skin and clothing repellents: WEAR CLOTHING PROPERLY Blouse or tuck your uniform legs into your boots and wear your sleeves down. Civilians should tuck their pant legs into their socks, and their shirt into their pants. Light colored clothing makes it easier to spot ticks. USE REPELLENTS Apply deet repellent, NSN 6840-01-284-3982, to any exposed skin surfaces, and apply permethrin repellent spray, NSN 6840-01-278-1336, to your uniform or field clothing. Remember that permethrin is only for use on clothing, NEVER on skin. This combined use of repellents and proper wearing of clothing will provide nearly complete protection from tick bites. IF YOU ARE BITTEN If you find a tick embedded in your skin, DO NOT SQUASH OR BURN IT. Report to medical personnel to have the tick removed, or follow these guidelines: Use tweezers to grasp the tick's mouthparts as close to the skin as possible, and pull it straight outward. Pull slowly, firmly, and steadily. Be patient. The ticks central mouthpart called the hypostome is long and covered with barbs. This can make it difficult to remove. Wash the wound site and apply an antiseptic. Save the tick either in alcohol or frozen in a pill vial or plastic bag in case symptoms arise and identification of the tick becomes necessary. BE AWARE Be aware of the symptoms of Lyme disease. IF YOU HAVE BEEN IN AN AREA WHERE TICKS ARE FOUND AND YOU DEVELOP A RASH AROUND THE SITE OF THE TICK BITE OR FLU-LIKE SYMPTOMS (ACHES AND PAINS, HEADACHE, FEVER, EXTREME FATIGUE), ESPECIALLY DURING THE PERIOD FROM MAY THROUGH EARLY FALL, PROMPTLY SEE A PHYSICIAN FOR EVALUATION. REMEMBER... Wear trousers inside boots and sleeves down; use skin (deet) and clothing (permethrin) repellents; check your clothing and body as frequently as possible; remove attached ticks as soon as they are discovered; seek medical attention if symptoms develop. FOR FURTHER INFORMATION CALL _____________________________________ APPENDIX E LYME DISEASE DETECTION METHODS Indirect Immunofluorescent Antibody Assay Methods for Spirochetes in Ticks: Infection status was determined by dissecting the midgut from the tick in phosphate buffered saline (PBS); triturating the tissues, and air drying on 10 well Teflon [registered]-coated spot slides (Cel-line, Inc.). These slides were fixed in acetone at -20 degrees C for 7 minutes and stored at -70 degrees C until assayed. The B. burgdorferi were observed using an IFA technique. The primary antibody used to detect the spirochete was a monoclonal antibody directed against the outer surface "A" protein (H 5332). The secondary detection antibody was Fluorescein isothiocyanate (FITC) conjugated Goat anti-mouse IgG (Heavy and Light chain, Kirkegaard & Perry Labs, Inc.). Indirect Immunofluorescent Antibody Assay Methods for Rodent Sera: An immunofluorescent antibody test was used to determine the prevalence of infection with Borrelia burgdorferi in rodents. Sera were initially screened for antibody response at a 1:32 dilution in PBS. Any samples yielding positive reaction at this dilution level were further titrated by fourfold dilution to 1:512. Serum samples were overlain in replicate onto B. burgdorferi-coated antigen spot slides (Cel-line, inc.) for 1 hour at room temperature in a humidified chamber. Slides were washed twice with PBS, and a detector antibody, FITC conjugated Goat anti-mouse IgG (Heavy and Light chain, Kirkegaard & Perry Labs, Inc.), was added to each well of the spot slides. Following a 30-minute incubation at room temperature, slides were washed twice with PBS, and cover-slipped. Slides were read under ultraviolet light at 400X magnification and response was graded as either strong (+), weak (+/-) or negative. Final antibody titer category for a sample was assigned based on the highest dilution yielding at least one strong response.