Lyme Disease Risk Assessment No. 16-07-3552-95, Little Rock Air Force Base, Arkansas, 17-21 April 1995. 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] REPLY TO ATTENTION OF: MCHB-AN-ES (40-5f) 1 July 1996 MEMORANDUM FOR Commander, 314th Airlift Wing, 370 Cannon Drive, Little Rock Air Force Base, Arkansas 72099-5000 SUBJECT: Lyme Disease Risk Assessment No. 16-07-3552-95, Little Rock Air Force Base, Arkansas, 17-21 April 1995. 1. Copies of subject report with Executive Summary are enclosed. 2. Please call me at DSN 923-5281/6205, extension 208, if you require additional information on this risk assessment or support in the areas of occupational and environmental health. FOR THE COMMANDER: [Signed for] RICHARD N. JOHNSON MAJ, MS Chief, Entomological Sciences Division ----- 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. 16-07-3552-95 LYME DISEASE RISK ASSESSMENT LITTLE ROCK AIR FORCE BASE, ARKANSAS 17-21 APRIL 1995 1. PURPOSE. To provide Lyme disease (LD) risk assessment to the Installation Commander, Little Rock Air Force Base (LRAFB), Arkansas and to assess the need for continued surveillance and education of military and civilian personnel on or in the vicinity of the installation. 2. FINDINGS. Seven adult LD vector ticks, Ixodes scapularis Say, were collected on dry-ice traps and tick drags (at a total of four sites), and ten larvae of this species were collected from three white-footed mice (at one site), during the above subject survey dates on the LRAFB, Arkansas. Nine small mammals were trapped, sampled (including a blood serum sample for Hantavirus antibody screening) and examined for ticks, during this survey. Tick drags and dry-ice traps on LRAFB yielded three male and four female black-legged ticks, I. scapularis. One of those females was positive for the LD agent, Borrelia burgdorferi; one other female, one male, and 8 of 9 larvae tested were positive for Borrelia spp. Tick drags and dry-ice traps also yielded two male and one female american dog ticks, Dermacentor variabilis, and numerous lone star ticks, Amblyomma americanum can transmit human ehrlichiosis. 3. RISK. The risk of contracting LD at LRAFB is presently moderate to high, this conclusion is based on the results of the survey combined with information from the Arkansas Department of Health (ADH) regarding human case reports and LD vector tick collection records from sites relatively near LRAFB. 4. RECOMMENDATIONS. Educate military, civilian, and dependent personnel using LRAFB for outdoor training or recreation on the use of personal protective measures, as addressed in Appendices D, E, and F of this report. Take measures to conduct periodic surveys for Lyme disease reservoirs (deer or small mammals), vectors (ticks), and/or evidence of prevalence of the LD pathogen to monitor risk level for Lyme disease. ----- 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] REPLY TO ATTENTION OF: MCHB-AN-ES LYME DISEASE RISK ASSESSMENT NO. 16-07-3552-95 LITTLE ROCK AIR FORCE BASE, ARKANSAS 17-21 APRIL 1995 1. REFERENCES. See Appendix A. 2. AUTHORITY. AEHA Form 250-R, Armstrong Lab/OEMB, 20 March 1995. 3. PURPOSE. To assess the risk of Lyme disease (LD) to Little Rock Air Force Base (LRAFB) personnel by performing tick drag surveillance of areas frequently used by humans and by collecting small mammals, examining them for known tick vectors of LD, especially Ixodes scapularis Say, and to assay ticks 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. 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. 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. b. Personnel Contacted. The purpose and methodology of this assessment were dicussed with Captain C. A. Fisher, SSGT Butler and A1C Bailey, of the Public Health Flight, 314th Medical Group, LRAFB; an out briefing was held with SSGT Butler. Also contacted were: Thomas Foti, Arkansas Natural Heritage Commission (regarding procurement of required hunting and trapping permits and current endangered/protected species information); and Dr. Gary Heidi, Biology Department, University of Arkansas at Little Rock, regarding current trapping background and results by himself and his students on or near LRAFB; and Dr. Paul Whit, Epidemiologist, ADH, Little Rock, Arkansas (regarding public health information and statistics). c. Survey Conduct. During the period of 17-21 April 1995, Dr. Harlan performed 240 trap-nights of small mammal trapping, 16 trap- nights of dry-ice trapping (for ticks), and greater than 2,500 meters (m.) of dragging for host-seeking ticks on LRAFB. Several hundred "Tick-Borne Disease" cards (GTA 8-5-56, see Appendix E), as well as on- the-spot briefings on LD and other tick-borne disease risks and prevention, were given to LRAFB personnel at every opportunity. Several hundred additional "Tick-Borne Disease" cards and a more detailed briefing were given to Public Health Flight and hospital personnel. d. 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. BACKGROUND. a. 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. b. The number of LD cases reported to the U.S. Centers for Disease Control and Prevention (CDC), by the Arkansas Department of Health (ADH), have increased slightly almost every year, from 1 case in 1983 to 21 cases in 1992. The ADH reported only 8 cases of LD, including 2 from Pulaski County (Co.), wherein LRAFB is located (1 of them from LRAFB itself), and 11 cases of RMSF from Arkansas in 1994. Only 7 cases of LD and 1 case of RMSF had been reported from the state in 1995 (none from Pulaski County), as of October (reference 6, Appendix A; and telephone conversation between Dr. Harlan and Dr. White, and ADH Epidemiologist, on 27 Nov 1995). 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. 6. METHODS. a. Small Mammal Trapping. All attempted collections of small mammals included only box-type live traps, baited with a mixture of about three parts peanut butter to one part bird seed (mostly millet) by weight. Traps were set in ecotonal area after 3:00 P.M., then checked and collected between 7:00 and 10:00 A.M. the next day. Small mammal trapping was performed in accordance with all provisions of Arkansas Department fo Natural Resources Scientific Research Permit No. 0090-95, dates: April 10, 1995. Specific guidance in references 2,3,4,11,12, and 13, Appendix A, were followed in the conduct of these live trapping efforts. A small blood sample (greater than or equal to 0.6 mL) was drawn via an orbital bleeding technique (reference 13, Appendix A) and the serum separated, kept frozen on dry ice or in an ultra-cold freezer (at temperatures of less than or equal to -32 degrees C) until tested for the presence of antibodies (Ab) against Hantaviruses by Dr. Brian Hjelle or his collaborators at the University of New Mexico. b. Dry Ice Trapping. A styrofoam box (roughly 6 in.x 6 in.x 12 in.) was filled with about 2 lb. of dry ice, taped shut, then placed in suspected tick habitat so that rows of tiny holes in the box's sides were above a 2 inch wide double-sided sticky tape strip completely encircling the bottom of the box. The theory was to force any ticks which might be attracted to the dry ice (CO.) to have to try to cross the tape, thus becoming stuck and remaining there until collected the next day. Each of these traps was left in place for at least 12 hours before it was collected, to allow immature ticks and slower moving species (e.g., larvae of most species; any stage of I. scapularis) to reach it from a radius of at least 1 m. c. Tick Dragging and Testing. The surveyor pulled ("dragged") a white flannel cloth through vegetation or over other surfaces where the target tick species were known or suspected to be found seeking (awaiting) a host. This usually included mixed grass, weeds, and brushy vegetation along the edge of a woods, clearing, trail or road (ecotonal areas) greater than or equal to 1 m. tall [North American tick species are almost never found seeking hosts greater than 1 m. above ground]. Drags were about 1 m. wide, with a stick attached to the leading edge (to support the cloth and keep it spread while it was pulled or dragged over surfaces being sampled), and another stick attached to the other end (to ensure the cloth is forced down and touched most sufaces to be sampled). After a drag had been passed over an area to be sampled, it was turned over, examined, and any tick(s) observed (usually obvious by their movement) were collected with tweezers into vials containing a small blade of grass or a small piece of very lightly moistened paper towel. Vials of ticks were kept chilled until returned to DSA-N for identification (ID) and testing for pathogens. In the DSA-N Entomology laboratory, B. burgdorferi organisms were tested for via direct fluorescent antibody (DFA) procedures (reference 8 and 9, Appendix A). 7. RESULTS. (Also see Appendices B, C, and G) a. Small Mammal Trapping. Nine white-footed mice, Peromyscus leucopus (Radinesque) were caught, sampled, examined for ticks, and released in accordance with the live-trapping permit cited above. Sera from all nine mice were found "negative" for the presence of any antibody against Hantaviruses in tests by Dr. Hjelle's lab at the University of New Mexico. b. Dry-Ice trapping. A total of 106 lone star ticks, A. americanum, were collected in the eight dry-ice trap-nights on LRAFB. Two american dog ticks, D. variabilis, a male and a female, plus one male deer, I. scapularis, were also collected in the same dry-ice trap-nights (Appendix B). c. Tick Dragging and Testing. Dragging greater than 2,500 m. of tick host-seeking (ecotonal) areas of LRAFB yielded 158 A. americanum (20 males, 4 females, 82 nymphs) from 11 sites (Appendix C). Dragging also yielded one male D. variabilis and six total (3 male; 3 female) I. scapularis (Appendix B). Lab tests via DFA (references 8 and 9, Appendix A were done on the seven adult and 9 of the 10 larval I. scapularis. One female was positive for B. burgdorferi, and one female, one male, and 8 of 9 larvae tested were positive for the presence of Borrelia spp. spirochetes, via polyclonal fluorescent antibodies, but negative for the LD organism, B. burgdorferi, via monoclonal antibodies. These collections and lab test results are listed in Appendix B. 8. DISCUSSION. In 1994, the ADH reported to CDC two human cases of LD from Pulaski County, Arkansas, and at least one human LD case from LRAFB itself. This, coupled with the collection of deer ticks, during this survey, from five sites on LRAFB (see Appendix G), DFA findings of at least one female deer tick positive for the LD organism, and collection of american dog ticks from the archery range and numerous lone star ticks throughout LRAFB, strongly support placing the risk level of contracting a tick-borne disease as medium to high. This justifies continued LD (and their tick-borne disease) surveillance and prevention efforts at LRAFB. 9. CONCLUSIONS. Recent increases in reported human cases of LD from Arkansas (more specifically, from Pulaski Co., and from LRAFB itself), collections of the vector ticks of three human pathogens on LRAFB, and one of these testing positive for LD organisms, all support a conclusion that the risk of contracting LD, or another tick-borne disease, on LRAFB is moderate to high, and may be increasing. 10. RECOMMENDATIONS. a. Periodically remind and retrain all military, civilian, and dependent personnel at LRAFB concerning the information on repellents which is contained in Appendices D, E, and F of this report. b. Assist this Activity, or take other steps, to ensure the conduct of periodic (suggested annual) surveys of deer, small mammals, or the environment for host-seeking ticks, and evidence of the presence and prevalence of B. burgdorferi, to determine the risk level of contracting LD at LRAFB. c. Report any LD cases to the Air Force Surgeon General's Office, ATTN: AFMOA/SGPA, Bolling AFB, Washington, DC; to Armstrong Labs, ATTN: AL/OEMD (Dr. McHugh), Brooks AFB, San Antonio, Texas; and to CDC, through the local (municipal or county) public health department and the ADH. The ADH Epidemiologist can be reached at (501)661-2111. 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 for] RICHARD N. JOHNSON MAJ, MS Chief, Entomological Sciences Division ----- APPENDIX A REFERENCES 1. DoD Directive 4150.7, Department of Defense Pest Management Program, 24 October 1983. 2. Armed Forces Pest Management Board Technical Information Memorandum No. 26, Lyme Disease: Vector Surveillance and Control, March 1990. 3. Office of Infectious Diseases, U.S. Center for Disease Control and Prevention (CDC). 1993. Hantavirus Infection - Southwestern United States: Interim Recommendations for Risk Reduction. Morbidity and Mortality Weekly Report (MMWR), Vol. 42 (RR-11), June 30. 4. Memorandum, Headquarters, U.S. Army Medical Command, ATTN: HCHO-CL-W (40), dated: 25 Jan 1995, subject: Policy on Protective Measures for Workers to Reduce the Risk of Hantavirus Exposure, 5pp. +6 enclosures (16 pp. total) 5. Technical Information Memorandum (TIM) No. 26. Lyme Disease Vector Surveillance and Control. Armed Forces Pest Management Board, Washington, DC. March 1990. 6. CDC. 1993. Lyme Disease Surveillance Summary. Vol. 4 (No. 3): June 1993. 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. 9. 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. 10. Ewing, S.A., J.E. Dawson, A.A. Kocan, R.W. Barker, C.K. Warner, R.J. Panciera, J.C. Fox, K.M. Kocan, and E.F. Blouin. 1995. Expermental transmission of Ehrlichia chaffeensis (Rickettsiales: Ehrlichieae) among white-tailed deer by Amblyomma americanum (Arcari: Ixodidae). J. Med. Entomol. 32(3): 368-374. 11. Burt, W.H., and R.P. Grossenheider. 1976. 3 ed. A Field Guide to the Mammals. Houghton-Mifflin Co., Boston. xxvii + 284 pp. 12. Anderson, R.M. 1965. 4 ed. Methods of Collecting and Preserving Vertebrate Animals. National Museum of Canada Bull. No. 69. vii + 199 pp. 13. Riley, V. 1960. Adaptation of orbital bleeding technic [sic] to rapid serial blood studies. Proc. Soc. Exp. Biol. Med. 104: 751-754. ----- APPENDIX B DATA SUMMARY SHEET DOD LYME DISEASE RISK ASSESSMENT U.S. ARMY CENTER FOR HEALTH PROMOTION AND PREVENTIVE MEDICINE DIRECT SUPPORT ACTIVITY-NORTH LITTLE ROCK AIR FORCE BASE, PULASKI COUNTY[1], ARKANSAS 17-21 APRIL 1995 ------------------------------------------------------------------------ Table B-1. Ticks Collected on Drags. No. No. No. Installation Tick Species Collected Tested Type of Test Positive ------------ ------------- ----------------------------------------- LRAFB A. americanum 158 0 N/A 0 D. variabilis 1 0 N/A 0 I. scapularis[2] 6 6 PC[3] PC=2 ------------------------------------------------------------------------ Table B-2. Ticks Collected from Dry-Ice Traps. No. No. No. Installation Tick Species Collected Tested Type of Test Positive ------------ ------------- ----------------------------------------- LRAFB A. americanum 106 0 N/A 0 D. variabilis 2 1 N/A 0 I. scapularis 1 0 N/A 0 ------------------------------------------------------------------------ Table B-3. Ticks collected from Mammals. No. No. No. Installation Tick Species Collected Tested Type of Test Positive ------------ ------------- ----------------------------------------- LRAFB I. scapularis 9 9 PC PC Only=8+ MC ------------------------------------------------------------------------ TOTAL A. americanum 264 0 N/A 0 D. variabilis 3 0 N/A 0 I. scapularis 7 7 PC 2 MC 1 ------------------------------------------------------------------------ 1 Pulaski Co., AR encompasses all of LRAFB, from which all samples were collected in this study. 2 Ixodes dammini Spielman, Clifford, Piesman, and Corwin and Ixodes scapularis Say were synonymized by Oliver st al. (1993), reference 7, Appendix A. 3 DFA techniques used here followed references 8 & 9, Appendix A. PC = Polyclonal antibodies which react with spirochetes of the genus Borrelia; MC = Monoclonal antibodies which react almost exclusively with spirochetes of the species Borrelia burgdorferi. Readings were done visually via ultraviolet microscopy. ----- APPENDIX C Noted as missing. ----- APPENDIX D Lyme Disease Risk Reduction Measures 1. Emphasize public awareness programs to educate troops, family members, civilian employees and visitors on personal protective measures and Lyme disease (and other tick-borne diseases). Methods should include, but not be limited to: a. Distribution of printed Lyme disease handouts, such as "tick- borne diseases" cards (GTA-8-5-56), pamphlets, and fact sheets. b. 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). c. 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. -------------------------------------- 1 3-M is a registered trademark of Minnesota Mining and Manufacturing Co., St. Paul, MN 55133-3053. ----- APPENDIX E REPELLENTS 1. Several arthropod repellents are available through the Defense General Supply Center (DGSC) or Self-Service Supply System. When used in accordance with 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: a. 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. b. 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. c. 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. ----- APPENDIX F 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 wqual 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. -----