1. A Comparative Study on the Efficacy of N-N-diethyl-m-toluamide, Picaridin, and Citronella as Repellents Against Aedes Aegypti

4. January to August 2012 –Dengue Fever:7321 cases –Dengue Hemorrhagic Fever:4181 cases January to August 2013 –Dengue Fever:2494 cases –Dengue Hemorrhagic Fever:1552 cases

5. Recent large clinical trial conducted in Thailand yielded only 30% effectivity of the dengue vaccine, 40% short of it’s expected outcome.

6. Celgosivir (6-O-butanoyl castanospermine), which misfolds the dengue NS1 protein is still in the initial stages of clinical trials.

7. Most Feasible Prevention

8. Insect Repellents DEET (N, N diethyl-meta-toluamide) –GOLD STANDARD –Blocks insect olfactory receptors –Toxic effects: impaired cognitive function Insomnia mood distrubances, severe epidermal reactions

9. Insect Repellents Non-DEET containing –Picaridin –Citronella

10. PICARIDIN ( 2-(2-hydroxyethyl)-1-piperidinecarboxylic acid 1-methylpropyl ester) used in Europe, Australia, Latin America and Asia as an alternative to DEET Unknown exact mechanism of action but repellency is comparable to that of DEET included in the list of effective repellents by the CDC

11. CITRONELLA plant-based insect repellent product from the steam distillation of freshly cut or partially dried grasses unkown exact mechanism of action but acts mainly as a feeding depressant US Environmental Protection Agency classifies citronella’s dermal toxicity as Category III or only slight toxicity if improperly used

12. General Objective –To compare the efficacy of different variants of insect repellents (DEET containing versus non-DEET containing versus plant-based) against mosquito landing and bites

13. Specific Objectives 1.To determine the LANDING frequency (mosquitoes landed on the subject, but not necessarily bit) for each variant of insect repellent 2.To compare the MEAN LANDING frequency of the insect repellents 3.To determine the BITING frequency for each variant of insect repellent

14. Specific Objectives 4. To compare the MEAN BITING frequency for the insect repellents 5. To determine which of the insect repellent variant provides the best protection against mosquito bites 6. To observe adverse events/reaction, if there is any, upon application/usage of the insect repellents

15. Materials and Methods STUDY DESIGN –Double blind randomized controlled trial Proposal reviewed and approved by IRB SETTING

16. STUDY POPULATION –any male or female –aged 18-50 years old –without pre-existing co-morbidities and allergies

17. Aedes Aegypti Mosquitoes

18. SAMPLE SIZE –9 (WHO and RITM protocol)

19. Repellents Tested A: N-N-diethyl-meta-toluamide (DEET) 25% B: Picaridin 10% C: Citronella

21. Informed consents were secured. Subjects were randomly allocated to three groups.

30. Eight trials Test mosquitoes replaced for each trial Each trial ran for 5 minutes Repellent was not reapplied prior to the next trial

31. Adverse Reactions were recorded –Rashes –Pain –Discomfort –Difficulty of Breathing

32. Events LANDING FREQUENCY: number of mosquitoes that LANDED on the test limb instantaneously BITING FREQUENCY: number of mosquitoes that landed on the test limb and are able to BITE the test limb, may be evidenced by the appearance of a rash/papule on the test limb

33. Statistical Analysis One-Way Analysis of Variance –To prove that at least two of the means are significantly different Tukey’s Test –To compare specific pairwise differences

34. Results

35. Landing Frequencies TRIA L 12345678MEANTOTA L DEET A2800361084.6256.43 B000023562.000 C0038290233812.625 PICARIDIN A51740133128353225.12547.12 B223240434870587448.375 C246657477592869667.875 CITRONELLA A306912790135105167132106.8865.33 B3244535280771139868.625 C61213232516264320.500

36. Hourly Landing Frequency

37. Biting Frequencies TRIA L 12345678MEANTOTA L DEET A0000000000.292 B000000000 C000060010.875 PICARIDIN A001012120.8751.333 B000000110.250 C246657477592869667.875 CITRONELLA A04130275010516713269.00032.04 B0712132623303217.875 C0911 137 109.250

38. Hourly Biting Frequency

39. One Way ANOVA (Landing) Critical Value (F): 5.14 Computed Test Statistic: 20.255 Decision: Reject Null Hypothesis SOURCEDegrees of Freedom Sum of Squares Mean Squares F Treatment214131.2665977.28820.255 Error61770.613295.102 Total815901.879

40. One Way ANOVA (Biting) Critical Value (F): 5.14 Computed Test Statistic: 0.729 Decision: Do not Reject Null Hypothesis SOURCEDegrees of Freedom Sum of Squares Mean Squares F Treatment21133.444395.2970.729 Error63251.901541.984 Total84385.345

41. Tukey’s Test (Landing) D min: 24.850 SET-UPABC 6.41747.12565.333 A 6.41740.70858.916 B 47.12518.208 C 65.333

42. NO allergic reactions noted

43. Discussion DEET, the gold standard, provided the best protection against mosquito bites based on landing and biting frequency Picaridin and citronella subjects acquired more landing and bites

44. -Consistent with studies done by Fradin and Beeyer -DEET is still the most effective mosquito repellent in the market.

45. Discussion INCREASE in the number of landing and bites as the trials progressed (waning of repellency)

46. Discussion One Way ANOVA for LANDING frequency: mean landing frequencies are SIGNIFICANTLY DIFFERENT from one another. One Way ANOVA for BITING frequency: mean biting frequencies are NOT SIGNIFICANTLY DIFFERENT from one another.

47. Discussion Less number of bites compared to landing in general Raw data: DEET subjects had the LEAST NUMBER of bites (best protection among the three)

48. Discussion Tukey’s test: In general, mean landing frequencies are SIGNIFICANTLY DIFFERENT

49. Discussion Consolidating raw data and statistical analysis –DEET is SUPERIOR to Picaridin and Citronella in repellency, based on LANDING and BITING frequency

50. Conclusion DEET is SUPERIOR to Picardin and Citronella based on LANDING and BITING frequency raw data One Way Analysis of Variance: MEAN LANDING frequencies are SIGNIFICANTLY DIFFERENT, MEAN BITING frequencies are NOT SIGNIFICANTLY DIFFERENT

51. Tukey’s Test: In general, MEAN LANDING frequencies are SIGNIFICANTLY DIFFERENT DEET provides the BEST PROTECTION against Aedes Aegypti

54. Limitations and Recommendations Minimum required sample size employed, larger sample size needed for a more conclusive study Only the landing and biting frequency were measured. Toxicity is another important parameter Future studies: recommendations on the safe levels of insect repellents