Eglin Air Force Base, FL

DEPARTMENT OF THE ARMY

U.S. Army Center for Health Promotion and Preventive Medicine

Direct Support Activity-North

Fort George G. Meade, Maryland 20755-5225

[Seal of Department of Defense, United States of America]

EXECUTIVE SUMMARY

PEST MANAGEMENT STUDY

NO. 16-07-3554-95

LYME DISEASE RISK ASSESSMENT FOR

EGLIN AIR FORCE BASE, FLORIDA

30 APRIL-5 MAY 1995

  1. PURPOSE. This study assesses the risk for military and civilian personnel of contracting Lyme disease while engaged in outdoor activities on Eglin Air Force Base (AFB), Florida.
  2. RESULTS. Sampling at Eglin AFB produced four Deer Ticks (Ixodes scapularis), the vector responsible for Lyme disease (LD) transmission. One of these ticks was positive for the LD agent (Borrelia burgdorferi). Two American Dog Tick, Dermacentor variabilis, were recovered while performing tick drags on the installation. This latter species can produce a medical condition known as tick paralysis and may transmit a number of human pathogens, including Rocky Mountain Spotted Fever. One Lone Star Tick (Amblyomma americanum), the vector of human monocytic ehrlichiosis, was collected.
  3. RISK. The risk of contracting LD at Eglin AFB is MODERATE. The risks for Rocky Mountain Spotted Fever and Human Monocytic Ehrlichiosis are LOW. We base these conclusions on the results of this survey and information regarding human case reports and vector tick collection records, from sites near Eglin AFB, from the Florida Department of Health (FDOH).
  4. RECOMMENDATION. All military and civilian personnel using Eglin AFB for outdoor training or recreation should use personal protective measures (PPM), as addressed in Appendices C, D, and E, of this report. These PMM will protect against tick bites, as well as the threat of disease transmission and annoyance from other man-biting arthropods. Personnel who find attached ticks on their bodies should carefully remove them and send them to installation public health personnel for identification. Additional surveys should be performed periodically (every three to five years) to update this assessment as Lyme disease and other arthropod and rodent-borne diseases are dynamic health threats.

LYME DISEASE RISK ASSESSMENT NO. 16-07-3554-95

EGLIN AIR FORCE BASE, FLORIDA

30 APRIL-5 MAY 1995

  1. REFERENCES. See Appendix A.
  2. AUTHORITY.
    1. a. DoD Lyme Disease Surveillance Program, Armed Forces Pest Management Board, October 1994.
    2. b. USAEHA Form 250-R, Armstrong Lab/OEMB, 20 Mar 95
  3. PURPOSE. To assess the risk of Lyme disease (LD) to Eglin Air Force Base, Florida by performing environmental sampling for the tick vectors of LD, especially Ixodes scapularis, and small mammals. Then to assay ticks and mice for evidence of the LD etiologic agent Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt & Brenner, in accordance with Department of Defense Directive (DoD Dir.) 4150.7.
  4. GENERAL.
    1. a. Risk Definition. The term "risk", as used in this report, is a non-statistical evaluation of qualitative and quantitative information on LD locally. To the extent available, information evaluated included the following elements:<
      1. History of LD in the area,
      2. The presence of the principal tick vector of LD (I. scapularis) and host populations needed to sustain viable populations of this vector,
      3. The presence of the LD-causing spirochete (B. burgdorferi) in the local tick population, and
      4. The presence of antibodies against B. burgdorferi in the blood serum of local mammal hosts.
        1. Once gathered, this information was used to help determine the general relative risk level as follows:
          • Low - Some elements of the LD cycle have been identified nearby, but not on the installation.
          • Moderate - Some elements of the LD cycle have been identified from the installation or human cases of LD have been reported from the local area.
          • High - All elements of the LD cycle have been found (are present) on the installation.
    2. Personnel Contacted. The purpose and methodology of this survey were dicussed with CPT Steven P. Nichoff and SGT Kevin T. Wilson, 96th AMDS/SGPM, Eglin AFB.
    3. Survey Conduct. Samples were collected by Dr. Harold Harlan, Direct Support Activity-North (DSA-North), using a protocol developed by DSA-North and materials provided by this Activity (DSA-North). SGT Wilson assisted in the conduct of the survey.
    4. Technical Assistance. Technical assistance or further informal advice may be obtained by contacting the Chief, Entomological Sciences Division, this Activity, commercial (310)677-5281/6502 or DSN 923- 5281/6502.
  5. 5. BACKGROUND.
    1. Lyme disease (LD) is a multi-symptomatic infectious disease caused by the spirochete, Borrelia burgdorferi Say [sic], which is transmitted to humans by the bite of an infected tick. This disease is usually called Lyme disease or Lyme arthritis in the United States. Over the past few years, it has become the most prevalent arthropod- borne disease in North America. Its geographic range is expanding and the number of reported cases has continued to rise nearly every year since 1989.
    2. The number of LD cases reported to the U.S. Centers for Disease Control and Prevention (CDC), by the Florida Department of Health (FDOH), have increased almost every year since 1985. In 1994, FDOH reported 27 cases in 1994; however only 19 cases were reported in 1995 (references 4 & 5 Appendix A). The lack of a rapid, sensitive, reliable, and cost-effective diagnostic test for LD results in proactive treatment before case confirmation and, consequently, under-reporting. The increased burden of reports on medical treatment facilities may also be a factor. Personnel concerned with LD prevention and control should not assume that human risk of LD has changed based solely on numbers of reported cases.
    3. Epidemiologic information from the FDOH indicates that there were no cases of LD reported from Santa Rosa, Okaloosa, and Walton Counties, wherein Eglin AFB is located, in either 1994 and 1995. Florida physicians have been reporting generally stable or gradually increasing numbers of human LD cases to CDC.
  6. METHODS.
    1. Environmental tick collection and testing. Ticks were collected along trails and forest edges using tick drags and dry ice traps. They were placed in vials and returned to this Activity to be identified. When I. scapularis were collected, they were tested via direct and indirect fluorescent antibody (DFA/IFA) techniques, as detailed by Piesman et al. (1986; reference 8, Appendix A) for the presence of B. burgdorferi.
    2. Small mammal collection and testing. Small mammal trapping was performed under the authority of Florida Game and Freshwater Fish Commission Scientific Collecting Permit No. WX95098-1995, using Sherman Live Traps (H.B. Sherman Traps, Inc., Tallahassee, FL). Approximately 50 traps were set out each evening during the period 30 April - 5 May 1995 and collected the following morning. When small mammals were collected, they were anesthetized and then examined about the eyes, ears, necks, and posterior for the presence of ticks. When ticks were detected, they were pulled off using fine-tipped forceps, placed into plastic vials, and forwarded to this Activity (DSA-North) for identification and possibly further testing.
  7. RESULTS. (Also see Appendix B) A total of four Deer Ticks (Ixodes scapularis) and one Lone Star Tick (Amblyomma americanum) were collected by tick drag at Eglin AFB during the period 30 April - 5 May 1995. No ticks were collected by dry ice traps. Two white-footed mice (Peromyscus leucopus) were collected during the survey. Two American Dog Ticks (Dermacentor varibilis) were collected from one of the mice. One of the four I. scapularis was found to be infected with Borrelia burgdorferi, the Lyme disease causal agent. The other three I. scapularis and one D. varibilis were positive for nonspecific spirochetes (not B. burgdorferi).
  8. DISCUSSION. The discovery of a deer tick infected with the LD- causing spirochete indicates the potential for human cases. The very low endemic deer tick population reduces the potential for human exposure. Florida maintains a very low incidence of human Lyme disease cases. Most of these cases are thought to have been people who became infected elsewhere, but were not diagnosed until their return to Florida. The presence of sandy, well drained soils in Florida, as a whole, are not conducive to maintaining the vector tick populations. Historically it has been thought that the presence of imported fire ants (Solenopsis invicta) has negatively impacted tick populations in Florida. During this survey, it was very rare to even encounter a tick on the western 2/3 of the Eglin Reservation. However, Lyme disease and other rodent and tick-borne diseases are among the emerging diseases of concern to public health officials throughout the U.S. Conducting periodic health threat assessments (every 3-5 years) of the arthropods and small mammals found on Eglin AFB would give the command a good grasp of the disease risk on the installation.
  9. CONCLUSIONS. Despite the discovery of the LD pathogen in a deer tick during this study, the low incidence of human Lyme disease cases in the Florida panhandle, together with the low density of ticks, support the conclusion that the risk of contracting LD on Eglin Air Force Base, FL is MODERATE, and probably stable. Risk for Rocky Mountain Spotted Fever and Human Monocytic Ehrlichiosis are LOW.
  10. RECOMMENDATIONS.
    1. Periodically remind and retrain all military and civilian personnel at Eglin AFB concerning the information on repellents in Appendices C, D, and E of this report.
    2. Assist this Activity, or take other steps, to ensure the conduct of periodic (suggested every 3-5 years) surveys of deer, small mammals, or the environment for host-seeking ticks, and evidence of the presence and prevalence of B. burgdorferi and other tick-borne pathogens, to determine the risk level of contracting LD, RMSF, or ehrlichiosis at Eglin AFB.
    3. Have persons with a history of tick bite or exhibiting suspicious symptoms report to a health care provider as soon as possible. If attached ticks are provided to installation public health personnel, species determination can be made.
  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 USACHPPM, DSA-North at DSN 923- 6502/5281/6205, or commercial (301)[677-]6502/5281/6205.

[signed by]

RICHARD N. JOHNSON

MAJ, MS

Chief, Entomological Sciences Division

-----

APPENDIX A

REFERENCES

  1. AR 40-5, Preventive Medicine, 15 October 1990.
  2. DoD Directive 4150.7, Department of Defense Pest Management Program, 24 October 1983.
  3. Armed Forces Pest Management Board Technical Information Memorandum No. 26, Lyme Disease: Vector Surveillance and Control, March 1990.
  4. Centers for Disease Control and Prevention. Lyme Disease-United States, 1994. MMWR, 44(24): 459-463. 23 June 1995.
  5. Centers for Disease Control and Prevention. Lyme Disease-United States, 1995. MMWR, 45(23): 481-484. 14 Jun 96.
  6. Barbour, A. G., S. L. Tessier, and W. J. Todd. 1983. Lyme disease spirochetes and ixodid tick spirochetes share a common surface antigenic determinant defined by a monoclonal antibody. Infect. Immunol., 41: 795-804.
  7. Oliver, J.H., M.R. Owsley, H.J. Hutcheson, A.M. James, C. Chen, W.S. Irby, E.M. Dotson, and D.K. McLain. 1993. Conspecificity of the ticks Ixodes scapularis and Ixodes dammini (Acari: Ixodidae). J. Med. Entomol., 30(1): 54-63.
  8. Piesman, J., T. N. Mather, S.R. Telford III, and A. Spielman. 1986. Concurrent Borrelia burgdorferi and Babesia microti infection in nymphal Ixodes dammini. J. Clin. Microbiol. 24: 446-447.

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APPENDIX B

DATA SUMMARY SHEET

DOD LYME DISEASE RISK ASSESSMENT

EGLIN AIR FORCE BASE

FLORIDA

30 April - 5 May 1995

# Ticks Collected – 7

# Ixodes scapularis[1] Collected – 4

# Rodents Collected – 2

# Human Lyme Disease cases 1994, Tri-county area[2] – 0

# Human Lyme Disease cases 1995, Tri-county area[2] – 0

# Human Lyme Disease Cases 1994, Florida[3] – 27

# Human Lyme Disease Cases 1995, Florida[3] – 19

------------------------------------------------------------------------

  1. Ixodes dammini Spielman, Clifford, Piesman, and Corwin and Ixodes scapularis Say were synonymized by Oliver et al. (1993).
  2. Santa Rosa, Okaloosa, Walton Counties, FL includes all areas on Eglin Air Force Base.
  3. Based on reference 4 & 5, Appendix A, of this report.

Table B-2. Identity of ticks collected on the installation through the use of tick drags.

------------------------------------------------------------------------

1 One male I. scapularis positive for B. burgdorferi, other 3 I. scapularis and larval D. variabilis positive for non-B. burgdorferi spirochetes.

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APPENDIX C

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 (and other tick-borne diseases). Methods should include, but not be limited to:
    1. Distribution of printed Lyme disease handouts, such as "tick- borne diseases" cards (GTA-8-5-56), pamphlets, and fact sheets.
    2. Notifications in the installation newsletter, local media, and post electronic media (e.g., closed-circuit TV), especially prior to the high-risk months (April-July).
    3. Making the following videos available for general viewing: "Lyme Disease: A Growing Threat (FAUPIN No. 504494DD, Army TVT No. 8-196) and "Application of the Arthropod Repellent System" (No. 708575, Army TVT No. 8-232).
  2. Submit tick specimens (both field-collected ticks and those removed from individuals) alive for identification and DFA testing to USACHPPM, DSA-North, Fort Meade, Maryland 20755-5225.
  3. Stock Permethrin Arthropod Repellent (NSN 6840-01-278-1336, box of 12 cans for $36.99), and 3M[1] 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)] through proper channels to both military and civilian public health authorities.
  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 (or other human pathogens). Sampling should be done in early summer when I. scapularis nymphs (the life stage responsible for most human Lyme disease infections) actively seek hosts. 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 and most other human disease vector ticks.
  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/dragging prior to habitat modification. Clear such sites in low-risk months (i.e., January-February).
  8. As a contingency, prepare to treat high-use areas with pesticides to reduce tick populations if surveillance yields large numbers of ticks (especially if any are found to contain human pathogens) and if non- chemical techniques (e.g., brush removal, mowing, raking) do not provide adequate control.

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1 3-M is a registered trademark of Minnesota Mining and Manufacturing Co., St. Paul, MN 55133-3053.

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APPENDIX D

REPELLENTS

  1. Several arthropod repellents 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 clothing, they provide personal protection against a wide variety of medically important insect/arthropod pests. Availability and current prices can be obtained by calling the DGSC at DSN 695-4865 or commercial (804) 790-4865. Repellents available for use are described below:
    1. Insect/Arthropod Repellent Lotion (cream, 2 fluid ounces), NSN 6840-01-0284-3982. This is for application to exposed skin, is not labeled for ticks, but will repel chigger mites and many biting flies.
    2. Permethrin Arthropod Repellent, Insect Repellent, Clothing Application (aerosol, 6 ounces), NSN 6840-01-278-1336. Approximately 75% of one can should be applied to each field uniform, and the remainder used to treat other items (e.g., mosquito netting). This 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.
    3. Insect Repellent, Fabric Treatment (liquid, 5.1 fluid ounces), NSN 6840-01-334-2666. The contents of one bottle are added to two gallons of water and applied with a 2-gallon sprayer (like the ones in field sanitation kits) at a pressure of 55 psi, to field uniforms, mosquito netting, or tent fabric to provide protection from ticks, biting flies, and other insects. Since many sprayers are not equipped with the required pressure gauge (NSN 3740- 01-332-8746), it may be necessary to obtain this type of pressure gauge and filter (NSN 4330-01- 332-1639), to retro-fit an available sprayer. Proper application, followed by complete drying of the fabric, can provide protection for the normal life of the uniform (180 days in the field), six launderings of mosquito netting, or 6-9 months effectiveness for treated tent fabric, depending on the climate of deployment site(s).
  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" cards (GTA 8-5-56) should be ordered through normal military publications channels. Limited numbers of these cards may be obtained from the Entomological Sciences Division, USACHPPM, DSA-North, at DSN 923-5281 or commercial (301)677-5281.

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APPENDIX E

FACT SHEET - MOSQUITO AND TICK REPELLENTS

  1. Repellents containing DEET (N,N-diethyl-3-methylbenzamide, formerly N,N-diethyl-m-tolumide) offer good protection against mosquitoes, and are made for application to skin.
  2. Repellents containing Permethrin offer excellent protection against ticks, and are formulated for application to clothing.
  3. DEET also offers protection against ticks, keeping them from attaching to treated skin (sometimes for long periods). Ticks do not generally attach in exposed areas, the primary areas to which DEET is to be applied (refer to any given product's label directions).
  4. Permethrin, conversely, offers considerable protection against many mosquito species, but it can't be applied to exposed skin (refer to any given product's label directions), the main area(s) mosquitoes usually bite. Permethrin is useful for treating bed netting and tents.
  5. Combined use of DEET on exposed skin (as for mosquito repellency) and Permethrin on clothing (as for tick repellency) offers maximum protection against both these (as well as many others). Always read and follow the label directions before using any compound.
  6. Do NOT use flea or tick collars. A toxic reaction can result. Humans have many sweat glands in their skin that can serve as avenues for chemical absorption. Dogs (and cats), do not have sweat glands in their skin and cool themselves by panting. In addition, most breeds of these pets have a thick hair layer (barrier) whichprotects their skin from direct contact with collars. Humans have very limited hair covering.
  7. Various lotion products claim protection against mosquitoes. Professional literature both supports and refutes benefits from lotions. Controlled tests have shown that mineral oil, a major component of most such lotion products, does reduce biting by several species of mosquitos on areas of treated skin. However, this reduction in biting is small when compared to the reduction by an equal amount of DEET in concurrent tests by USDA labs.
  8. Controlled tests have shown that products containing high concentrations of DEET (greater than or equal to 50%) do not offer greater protection than products containing 30-50% DEET.
  9. The following practices enhance the effectiveness (degree of protection) against mosquitoes and ticks when used in conjunction with repellents:
    • Cover as much exposed skin as possible. Consider wearing loose- fitting long-sleeved shirts in summer.
    • Tuck pants legs inside tops of socks or boots.
    • Wear light-colored clothing to make ticks easier to see as they crawl.
    • Plan ahead and treat clothing with permethrin before starting your outdoor activity. Permethrin binds with fabric and is persistent through several detergent washings. ("Dry cleaning" will remove it immediately.)
    • Store treated clothing in a plastic bag to help preserve repellent effectiveness, and to help identify which clothing has been treated.

ALL BOLDING IS AN INSERT.DEPARTMENT OF THE ARMY

U.S. Army Center for Health Promotion and Preventive Medicine

Direct Support Activity-North

Fort George G. Meade, Maryland 20755-5225

[Seal of Department of Defense, United States of America]

EXECUTIVE SUMMARY

PEST MANAGEMENT STUDY

NO. 16-07-3554-95

LYME DISEASE RISK ASSESSMENT FOR

EGLIN AIR FORCE BASE, FLORIDA

30 APRIL-5 MAY 1995

  1. PURPOSE. This study assesses the risk for military and civilian personnel of contracting Lyme disease while engaged in outdoor activities on Eglin Air Force Base (AFB), Florida.
  2. RESULTS. Sampling at Eglin AFB produced four Deer Ticks (Ixodes scapularis), the vector responsible for Lyme disease (LD) transmission. One of these ticks was positive for the LD agent (Borrelia burgdorferi). Two American Dog Tick, Dermacentor variabilis, were recovered while performing tick drags on the installation. This latter species can produce a medical condition known as tick paralysis and may transmit a number of human pathogens, including Rocky Mountain Spotted Fever. One Lone Star Tick (Amblyomma americanum), the vector of human monocytic ehrlichiosis, was collected.
  3. RISK. The risk of contracting LD at Eglin AFB is MODERATE. The risks for Rocky Mountain Spotted Fever and Human Monocytic Ehrlichiosis are LOW. We base these conclusions on the results of this survey and information regarding human case reports and vector tick collection records, from sites near Eglin AFB, from the Florida Department of Health (FDOH).
  4. RECOMMENDATION. All military and civilian personnel using Eglin AFB for outdoor training or recreation should use personal protective measures (PPM), as addressed in Appendices C, D, and E, of this report. These PMM will protect against tick bites, as well as the threat of disease transmission and annoyance from other man-biting arthropods. Personnel who find attached ticks on their bodies should carefully remove them and send them to installation public health personnel for identification. Additional surveys should be performed periodically (every three to five years) to update this assessment as Lyme disease and other arthropod and rodent-borne diseases are dynamic health threats.

LYME DISEASE RISK ASSESSMENT NO. 16-07-3554-95

EGLIN AIR FORCE BASE, FLORIDA

30 APRIL-5 MAY 1995

  1. REFERENCES. See Appendix A.
  2. AUTHORITY.
    1. a. DoD Lyme Disease Surveillance Program, Armed Forces Pest Management Board, October 1994.
    2. b. USAEHA Form 250-R, Armstrong Lab/OEMB, 20 Mar 95
  3. PURPOSE. To assess the risk of Lyme disease (LD) to Eglin Air Force Base, Florida by performing environmental sampling for the tick vectors of LD, especially Ixodes scapularis, and small mammals. Then to assay ticks and mice for evidence of the LD etiologic agent Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt & Brenner, in accordance with Department of Defense Directive (DoD Dir.) 4150.7.
  4. GENERAL.
    1. a. Risk Definition. The term "risk", as used in this report, is a non-statistical evaluation of qualitative and quantitative information on LD locally. To the extent available, information evaluated included the following elements:<
      1. History of LD in the area,
      2. The presence of the principal tick vector of LD (I. scapularis) and host populations needed to sustain viable populations of this vector,
      3. The presence of the LD-causing spirochete (B. burgdorferi) in the local tick population, and
      4. The presence of antibodies against B. burgdorferi in the blood serum of local mammal hosts.
        1. Once gathered, this information was used to help determine the general relative risk level as follows:
          • Low - Some elements of the LD cycle have been identified nearby, but not on the installation.
          • Moderate - Some elements of the LD cycle have been identified from the installation or human cases of LD have been reported from the local area.
          • High - All elements of the LD cycle have been found (are present) on the installation.
    2. Personnel Contacted. The purpose and methodology of this survey were dicussed with CPT Steven P. Nichoff and SGT Kevin T. Wilson, 96th AMDS/SGPM, Eglin AFB.
    3. Survey Conduct. Samples were collected by Dr. Harold Harlan, Direct Support Activity-North (DSA-North), using a protocol developed by DSA-North and materials provided by this Activity (DSA-North). SGT Wilson assisted in the conduct of the survey.
    4. Technical Assistance. Technical assistance or further informal advice may be obtained by contacting the Chief, Entomological Sciences Division, this Activity, commercial (310)677-5281/6502 or DSN 923- 5281/6502.
  5. 5. BACKGROUND.
    1. Lyme disease (LD) is a multi-symptomatic infectious disease caused by the spirochete, Borrelia burgdorferi Say [sic], which is transmitted to humans by the bite of an infected tick. This disease is usually called Lyme disease or Lyme arthritis in the United States. Over the past few years, it has become the most prevalent arthropod- borne disease in North America. Its geographic range is expanding and the number of reported cases has continued to rise nearly every year since 1989.
    2. The number of LD cases reported to the U.S. Centers for Disease Control and Prevention (CDC), by the Florida Department of Health (FDOH), have increased almost every year since 1985. In 1994, FDOH reported 27 cases in 1994; however only 19 cases were reported in 1995 (references 4 & 5 Appendix A). The lack of a rapid, sensitive, reliable, and cost-effective diagnostic test for LD results in proactive treatment before case confirmation and, consequently, under-reporting. The increased burden of reports on medical treatment facilities may also be a factor. Personnel concerned with LD prevention and control should not assume that human risk of LD has changed based solely on numbers of reported cases.
    3. Epidemiologic information from the FDOH indicates that there were no cases of LD reported from Santa Rosa, Okaloosa, and Walton Counties, wherein Eglin AFB is located, in either 1994 and 1995. Florida physicians have been reporting generally stable or gradually increasing numbers of human LD cases to CDC.
  6. METHODS.
    1. Environmental tick collection and testing. Ticks were collected along trails and forest edges using tick drags and dry ice traps. They were placed in vials and returned to this Activity to be identified. When I. scapularis were collected, they were tested via direct and indirect fluorescent antibody (DFA/IFA) techniques, as detailed by Piesman et al. (1986; reference 8, Appendix A) for the presence of B. burgdorferi.
    2. Small mammal collection and testing. Small mammal trapping was performed under the authority of Florida Game and Freshwater Fish Commission Scientific Collecting Permit No. WX95098-1995, using Sherman Live Traps (H.B. Sherman Traps, Inc., Tallahassee, FL). Approximately 50 traps were set out each evening during the period 30 April - 5 May 1995 and collected the following morning. When small mammals were collected, they were anesthetized and then examined about the eyes, ears, necks, and posterior for the presence of ticks. When ticks were detected, they were pulled off using fine-tipped forceps, placed into plastic vials, and forwarded to this Activity (DSA-North) for identification and possibly further testing.
  7. RESULTS. (Also see Appendix B) A total of four Deer Ticks (Ixodes scapularis) and one Lone Star Tick (Amblyomma americanum) were collected by tick drag at Eglin AFB during the period 30 April - 5 May 1995. No ticks were collected by dry ice traps. Two white-footed mice (Peromyscus leucopus) were collected during the survey. Two American Dog Ticks (Dermacentor varibilis) were collected from one of the mice. One of the four I. scapularis was found to be infected with Borrelia burgdorferi, the Lyme disease causal agent. The other three I. scapularis and one D. varibilis were positive for nonspecific spirochetes (not B. burgdorferi).
  8. DISCUSSION. The discovery of a deer tick infected with the LD- causing spirochete indicates the potential for human cases. The very low endemic deer tick population reduces the potential for human exposure. Florida maintains a very low incidence of human Lyme disease cases. Most of these cases are thought to have been people who became infected elsewhere, but were not diagnosed until their return to Florida. The presence of sandy, well drained soils in Florida, as a whole, are not conducive to maintaining the vector tick populations. Historically it has been thought that the presence of imported fire ants (Solenopsis invicta) has negatively impacted tick populations in Florida. During this survey, it was very rare to even encounter a tick on the western 2/3 of the Eglin Reservation. However, Lyme disease and other rodent and tick-borne diseases are among the emerging diseases of concern to public health officials throughout the U.S. Conducting periodic health threat assessments (every 3-5 years) of the arthropods and small mammals found on Eglin AFB would give the command a good grasp of the disease risk on the installation.
  9. CONCLUSIONS. Despite the discovery of the LD pathogen in a deer tick during this study, the low incidence of human Lyme disease cases in the Florida panhandle, together with the low density of ticks, support the conclusion that the risk of contracting LD on Eglin Air Force Base, FL is MODERATE, and probably stable. Risk for Rocky Mountain Spotted Fever and Human Monocytic Ehrlichiosis are LOW.
  10. RECOMMENDATIONS.
    1. Periodically remind and retrain all military and civilian personnel at Eglin AFB concerning the information on repellents in Appendices C, D, and E of this report.
    2. Assist this Activity, or take other steps, to ensure the conduct of periodic (suggested every 3-5 years) surveys of deer, small mammals, or the environment for host-seeking ticks, and evidence of the presence and prevalence of B. burgdorferi and other tick-borne pathogens, to determine the risk level of contracting LD, RMSF, or ehrlichiosis at Eglin AFB.
    3. Have persons with a history of tick bite or exhibiting suspicious symptoms report to a health care provider as soon as possible. If attached ticks are provided to installation public health personnel, species determination can be made.
  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 USACHPPM, DSA-North at DSN 923- 6502/5281/6205, or commercial (301)[677-]6502/5281/6205.

[signed by]

RICHARD N. JOHNSON

MAJ, MS

Chief, Entomological Sciences Division

-----

APPENDIX A

REFERENCES

  1. AR 40-5, Preventive Medicine, 15 October 1990.
  2. DoD Directive 4150.7, Department of Defense Pest Management Program, 24 October 1983.
  3. Armed Forces Pest Management Board Technical Information Memorandum No. 26, Lyme Disease: Vector Surveillance and Control, March 1990.
  4. Centers for Disease Control and Prevention. Lyme Disease-United States, 1994. MMWR, 44(24): 459-463. 23 June 1995.
  5. Centers for Disease Control and Prevention. Lyme Disease-United States, 1995. MMWR, 45(23): 481-484. 14 Jun 96.
  6. Barbour, A. G., S. L. Tessier, and W. J. Todd. 1983. Lyme disease spirochetes and ixodid tick spirochetes share a common surface antigenic determinant defined by a monoclonal antibody. Infect. Immunol., 41: 795-804.
  7. Oliver, J.H., M.R. Owsley, H.J. Hutcheson, A.M. James, C. Chen, W.S. Irby, E.M. Dotson, and D.K. McLain. 1993. Conspecificity of the ticks Ixodes scapularis and Ixodes dammini (Acari: Ixodidae). J. Med. Entomol., 30(1): 54-63.
  8. Piesman, J., T. N. Mather, S.R. Telford III, and A. Spielman. 1986. Concurrent Borrelia burgdorferi and Babesia microti infection in nymphal Ixodes dammini. J. Clin. Microbiol. 24: 446-447.

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APPENDIX B

DATA SUMMARY SHEET

DOD LYME DISEASE RISK ASSESSMENT

EGLIN AIR FORCE BASE

FLORIDA

30 April - 5 May 1995

# Ticks Collected – 7

# Ixodes scapularis[1] Collected – 4

# Rodents Collected – 2

# Human Lyme Disease cases 1994, Tri-county area[2] – 0

# Human Lyme Disease cases 1995, Tri-county area[2] – 0

# Human Lyme Disease Cases 1994, Florida[3] – 27

# Human Lyme Disease Cases 1995, Florida[3] – 19

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  1. Ixodes dammini Spielman, Clifford, Piesman, and Corwin and Ixodes scapularis Say were synonymized by Oliver et al. (1993).
  2. Santa Rosa, Okaloosa, Walton Counties, FL includes all areas on Eglin Air Force Base.
  3. Based on reference 4 & 5, Appendix A, of this report.

Table B-2. Identity of ticks collected on the installation through the use of tick drags.

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1 One male I. scapularis positive for B. burgdorferi, other 3 I. scapularis and larval D. variabilis positive for non-B. burgdorferi spirochetes.

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APPENDIX C

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 (and other tick-borne diseases). Methods should include, but not be limited to:
    1. Distribution of printed Lyme disease handouts, such as "tick- borne diseases" cards (GTA-8-5-56), pamphlets, and fact sheets.
    2. Notifications in the installation newsletter, local media, and post electronic media (e.g., closed-circuit TV), especially prior to the high-risk months (April-July).
    3. Making the following videos available for general viewing: "Lyme Disease: A Growing Threat (FAUPIN No. 504494DD, Army TVT No. 8-196) and "Application of the Arthropod Repellent System" (No. 708575, Army TVT No. 8-232).
  2. Submit tick specimens (both field-collected ticks and those removed from individuals) alive for identification and DFA testing to USACHPPM, DSA-North, Fort Meade, Maryland 20755-5225.
  3. Stock Permethrin Arthropod Repellent (NSN 6840-01-278-1336, box of 12 cans for $36.99), and 3M[1] 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)] through proper channels to both military and civilian public health authorities.
  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 (or other human pathogens). Sampling should be done in early summer when I. scapularis nymphs (the life stage responsible for most human Lyme disease infections) actively seek hosts. 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 and most other human disease vector ticks.
  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/dragging prior to habitat modification. Clear such sites in low-risk months (i.e., January-February).
  8. As a contingency, prepare to treat high-use areas with pesticides to reduce tick populations if surveillance yields large numbers of ticks (especially if any are found to contain human pathogens) and if non- chemical techniques (e.g., brush removal, mowing, raking) do not provide adequate control.

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1 3-M is a registered trademark of Minnesota Mining and Manufacturing Co., St. Paul, MN 55133-3053.

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APPENDIX D

REPELLENTS

  1. Several arthropod repellents 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 clothing, they provide personal protection against a wide variety of medically important insect/arthropod pests. Availability and current prices can be obtained by calling the DGSC at DSN 695-4865 or commercial (804) 790-4865. Repellents available for use are described below:
    1. Insect/Arthropod Repellent Lotion (cream, 2 fluid ounces), NSN 6840-01-0284-3982. This is for application to exposed skin, is not labeled for ticks, but will repel chigger mites and many biting flies.
    2. Permethrin Arthropod Repellent, Insect Repellent, Clothing Application (aerosol, 6 ounces), NSN 6840-01-278-1336. Approximately 75% of one can should be applied to each field uniform, and the remainder used to treat other items (e.g., mosquito netting). This 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.
    3. Insect Repellent, Fabric Treatment (liquid, 5.1 fluid ounces), NSN 6840-01-334-2666. The contents of one bottle are added to two gallons of water and applied with a 2-gallon sprayer (like the ones in field sanitation kits) at a pressure of 55 psi, to field uniforms, mosquito netting, or tent fabric to provide protection from ticks, biting flies, and other insects. Since many sprayers are not equipped with the required pressure gauge (NSN 3740- 01-332-8746), it may be necessary to obtain this type of pressure gauge and filter (NSN 4330-01- 332-1639), to retro-fit an available sprayer. Proper application, followed by complete drying of the fabric, can provide protection for the normal life of the uniform (180 days in the field), six launderings of mosquito netting, or 6-9 months effectiveness for treated tent fabric, depending on the climate of deployment site(s).
  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" cards (GTA 8-5-56) should be ordered through normal military publications channels. Limited numbers of these cards may be obtained from the Entomological Sciences Division, USACHPPM, DSA-North, at DSN 923-5281 or commercial (301)677-5281.

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APPENDIX E

FACT SHEET - MOSQUITO AND TICK REPELLENTS

  1. Repellents containing DEET (N,N-diethyl-3-methylbenzamide, formerly N,N-diethyl-m-tolumide) offer good protection against mosquitoes, and are made for application to skin.
  2. Repellents containing Permethrin offer excellent protection against ticks, and are formulated for application to clothing.
  3. DEET also offers protection against ticks, keeping them from attaching to treated skin (sometimes for long periods). Ticks do not generally attach in exposed areas, the primary areas to which DEET is to be applied (refer to any given product's label directions).
  4. Permethrin, conversely, offers considerable protection against many mosquito species, but it can't be applied to exposed skin (refer to any given product's label directions), the main area(s) mosquitoes usually bite. Permethrin is useful for treating bed netting and tents.
  5. Combined use of DEET on exposed skin (as for mosquito repellency) and Permethrin on clothing (as for tick repellency) offers maximum protection against both these (as well as many others). Always read and follow the label directions before using any compound.
  6. Do NOT use flea or tick collars. A toxic reaction can result. Humans have many sweat glands in their skin that can serve as avenues for chemical absorption. Dogs (and cats), do not have sweat glands in their skin and cool themselves by panting. In addition, most breeds of these pets have a thick hair layer (barrier) whichprotects their skin from direct contact with collars. Humans have very limited hair covering.
  7. Various lotion products claim protection against mosquitoes. Professional literature both supports and refutes benefits from lotions. Controlled tests have shown that mineral oil, a major component of most such lotion products, does reduce biting by several species of mosquitos on areas of treated skin. However, this reduction in biting is small when compared to the reduction by an equal amount of DEET in concurrent tests by USDA labs.
  8. Controlled tests have shown that products containing high concentrations of DEET (greater than or equal to 50%) do not offer greater protection than products containing 30-50% DEET.
  9. The following practices enhance the effectiveness (degree of protection) against mosquitoes and ticks when used in conjunction with repellents:
    • Cover as much exposed skin as possible. Consider wearing loose- fitting long-sleeved shirts in summer.
    • Tuck pants legs inside tops of socks or boots.
    • Wear light-colored clothing to make ticks easier to see as they crawl.
    • Plan ahead and treat clothing with permethrin before starting your outdoor activity. Permethrin binds with fabric and is persistent through several detergent washings. ("Dry cleaning" will remove it immediately.)
    • Store treated clothing in a plastic bag to help preserve repellent effectiveness, and to help identify which clothing has been treated.

ALL BOLDING IS AN INSERT.

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