Fight the Bite! ARTHROPOD BITES. Vernon Ansdell, MD, FRCP, DTM&H Tropical & Travel Medicine Kaiser Hawaii

Transcription

1 Fight the Bite! Vernon Ansdell, MD, FRCP, DTM&H Tropical & Travel Medicine Kaiser Hawaii ARTHROPOD BITES Mosquito transmitted infections are responsible for the deaths of 1 in 17 people currently alive Arthropod transmitted infections are responsible for 1 death every 30 seconds million cases of malaria every year 1 million deaths from malaria every year 1000 cases of malaria in US travelers every year 5-10 (0-13) deaths from malaria in US travelers every year

2

3

4

5

6 IDEAL INSECT REPELLENT Broad spectrum and highly effective Long lasting (>8 hours) No local irritation No systemic toxicity Cosmetically appealing, greaseless, odorless Resistant to abrasion and washoff

7 INSECT REPELLENTS Chemical (manufactured) Repellents DEET Picaridin IR3535 Natural (Plant derived) Repellents Eucalyptus Citronella Neem Insecticides Permethrin DEET (N, N-diethylmetatoluamide) Gold standard Available in US since 1957 Used by 30% of US population every year Worldwide use > 200 million people every year 8 billion applications in 50 years use worldwide Broad spectrum protection Colorless, oily, aromatic. May damage plastic,fabrics Available in US as 5-40% and 100% DEET High concentrations last longer. The degree of effectiveness is not influenced by concentration. Plateau of effectiveness at 50% DEET.

8 DEET (N, N- diethylmetatoluamide) Extended Release Formulations Controlled Release DEET 20% (Sawyer) Ultrathon 35% DEET (3M) Comparable to DEET 50% Reduced absorption Increased duration DEET TOXICITY 8 billion applications in 50 years. <50 significant cases of DEET toxicity in literature over 50 years. Dermatologic, neurologic, cardiovascular Often associated with extended, excessive or inappropriate use. Details of exposure poorly documented. Most resolved without sequelae.

9 DEET AND SUNSCREEN Combination not recommended DEET may reduce effectiveness of sunscreen by 30% Apply sunscreen first, wait 30 minutes and then apply DEET No data on sunscreens and other repellents PICARIDIN Piperidine KBR 3033 Available in Europe and Australia for several years (Picaridin 19%) Available in US since 2005 as Picaridin 7%.Recently available as Picaridin 20% Odorless. Non-greasy or sticky. Non-toxic No damage to plastics or fabrics PICARIDIN Higher concentrations comparable to DEET 20-30% or extended release DEET vs: Anopheles, Aedes, Culex mosquitoes Stomoxys Culicidae Tabanid flies Ticks (shorter duration)

10 IR3535 ethylbutylaminoproprionate Available in Europe for 20 years and US since 1999 Avon Skin-So-Soft Bug Guard Plus Concentration % Limited effectiveness. IR % provided only 23 minutes (range mins) complete protection vs. Aedes aegypti. IR % less effective than DEET 7%. EUCALYPTUS p-menthane-3, 8-diol (PMD) Oil extract from lemon eucalyptus Available commercially in UK & USA PMD 30% comparable to DEET 15-20%, but requires more frequent reapplication Limited studies using Anopheles mosquitoes Low toxicity Safe on plastics, clothing Significant eye irritation Strong herbal scent Broad spectrum

11 NEEM Azadiracta indica Benefits recognized in India for 4,000 years Repellent and insecticidal properties Probably safe, non toxic Multiple benefits claimed Limited evidence on effectiveness as a repellent

12 PERMETHRIN Derived from chrysanthemums Rapidly acting insecticide Broad spectrum repellent Poorly absorbed via skin, rapidly metabolized Odorless, non-staining Safe on plastics and clothing Non-toxic in humans (?? link with parkinsonism) Used to impregnate clothing, bed nets DEET PLUS PERMETHRIN Mosquito Bites Per Hour Skin Clothes Overall % Protection DSPC DS PC

13 DEET PLUS PERMETHRIN Tsetse Fly Bites Per 75 Mins Skin Clothes Overall % Protection DSPC DS PC

14 INSECT REPELLENTS Ineffective Agents Vitamin B Garlic Avon Skin-So-Soft Bath Oil Electronic buzzers Impregnated wrist bands REPELLENT STUDIES Laboratory study, Aedes aegypti (arm in cage) Multiple repellents available commercially in US Fradin NEJM 2002, 347:13

15 FRADIN NEJM 2002, 347: hrs Time to 1 st Bite (hours) hrs 2 hrs 1-1/2 hrs 1 1/3 hr 1/2 hr 0 DEET 24% Sawyer CR DEET DEET 7% Soybean Oil 2% IR 3535 Citronella 10% 20% PICARIDIN STUDIES Field trial, various night biting mosquitoes Picaridin 19.2% and 9.3% vs DEET 35% Picaridin 19.2% > 95% protection for > 9 hours Picaridin 9.3% > 95% protection for 2 hours DEET 35% > 95% protection for 7 hours Frances et al J Med Entomol 2002, 39:541 PICARIDIN STUDIES Laboratory study, Aedes aegypti, Anopheles gambiae Picaridin vs DEET (varying concentrations) Picaridin at least as effective as DEET; both less effective against A gambiae than Ae aegypti Badolo et al Trop Med Int Health 2004, 9:330

16 PICARIDIN STUDIES Field trial, Various day biting mosquitoes Picaridin 19.2% vs DEET 20% (CR Sawyer) vs DEET 35% (EDTIAR) CR Sawyer DEET 20% > 95% protection for 6 hours Picaridin 19.2%, EDTIAR DEET 35% > 95% protection for > 8 hours Frances et al J Med Entomol 2002, 39:541 PICARIDIN STUDIES Field trial, Culex annulirostris, Anopheles bancrofti and meraukensis Picaridin 19.2% vs DEET 20% and DEET 35% Cx annulirostris Picaridin 5 hours, DEET > 7 hours Anopheles species Picaridin 1 hour, DEET 20% < 1 hr, DEET 35% 1 hr Frances et al J Med Entomol 2004, 41:4.14

17 PICARIDIN STUDIES Laboratory study, Phlebotomus dubosqi Picaridin 10 and 20%, vs. DEET 50% Picaridin 20% 8-10 hours protection Picaridin 10% 9 hours protection DEET 50% 9 hours protection Perrotey et al Parasitol Res 2002, 88:712 PICARIDIN STUDIES Picaridin 20% vs DEET 20% Laboratory study, Amblyomma hebraeum (African TBF) Protection after 1, 2, 3, 4 hours Picaridin > 85%, 56%, 55%, 54% DEET > 85%, 84%, 68%, 71% Pretorius et al J Med Entomol 2003, 40:245

18 REPELLENT STUDIES Laboratory study, Aedes albopictus, Culex nigripalpus, Ochlerotatus triseriatus (arm in cage) Multiple commercially available repellents Barnard et al J Med Entomol 2004, 41:726 REPELLENT STUDIES Repellent Repellency Index Neem 0.3 Citronella 10% 0.5 IR DEET 7% 1.0 DEET 15% 1.5 Bite Blocker 1.5 Picaridin 10% 1.5 Eucalyptus 1.7 INTEGRATED APROACH TO PERSONAL PROTECTION VS INSECT BITES DEET on the skin (extended release products) Alternative repellents if indicated Bed nets Permethrin on clothing and bed nets Mosquito vapor mats, mosquito coils Long sleeves, long pants Screened windows, doors. Air conditioning Avoid dark clothes Avoid perfumes, colognes Insecticide sprays

19 INTEGRATED APROACH TO PERSONAL PROTECTION VS INSECT BITES DEET on the skin (extended release products) Alternative repellents if indicated Mosquito nets Permethrin on clothing and bed nets Mosquito vapor mats, mosquito coils Long sleeves, long pants Screened windows, doors. Air conditioning Avoid dark clothes Avoid perfumes, colognes Insecticide sprays

20 Arthropod Repellents EBM Recommendations Permethrin treated mosquito nets increase protection Travelers at risk of serious insect borne infections should use DEET EBM Rating A1 A1 Arthropod Repellents EBM Recommendations Travelers at risk of insect borne infection: Screened windows Permethrin treated mosquito nets Permethrin treated clothing Long pants, long sleeves Light colored clothing Mosquito nets EBM Rating B2

21 Arthropod Repellents EBM Recommendations ER DEET products preferred over standard DEET Avoid citronella products Consider picaridin or eucalyptus if DEET contraindicated Picaridin (20%) as effective as DEET (15-20%) EBM Rating B1 E2 A2 A2 Arthropod Repellents EBM Recommendations Ineffective Protective Measures: Electronic (ultrasonic) devices Wristbands Bug zappers Oral vitamin B1 Skin So Soft Bath Oil EBM Rating E2

22 References 1. Barnard, DR, et al, J Med Entomol 2004; 41 (4): Fradin, MS, et al, N Engl J Med 2002; 347:13 3. Badolo, A, et al, Trop Med Int Health 2004; 9: Frances, SP, et al, J Med Entomol 2004; 41: Costantini, C, et al, Trans R Soc Trop Med Hyg 2004; 98: Barnard, DR, et al, J Med Entomol 2002; 39:895