Presentation done last October 8, 2010 at Fairchild Semiconductor, EPZA 1, Lapu-Lapu City, Cebu, Philippines. Some data reflects regional situation. Data from statistics presented does not reflect current situation; however, links are provided for further information.

1. Preventing Dengue The Vector, The Virus, and The Fever Prepared & Designed by: Raphael D. Fernandez, M.D. Website: www.raphaelfernandez.com 10/12/2010 1

2. Question Why should we be concerned about Dengue? 10/12/2010 2

3. Dengue Worldwide, WHO estimates 2.5 billion people are at risk with 50 million cases annually. Fatality rate: <1% to 20% depending on health care DHF develops in 1/100 cases Nationwide, 90,771 cases were recorded from January to Sept 29, 2010 Case fatality rate: 1% 10/12/2010 3

4. Dengue Update A total of 9,284 cases seen in Region 7 from January 1 to October 2, 2010 65 deaths (CFR=0.7%) 2009, 4,961/67 (CFR=1.4%) Ages: 1-89 y.o. (↑6-10 y.o) Sex: Male = Female Areas: Cebu City > Tagbilaran > Dumaguete > Lapulapu > Toledo 10/12/2010 4 “Dengue Update,” 39th Morbidity Week

5. Dengue Update, Central Visayas 10/12/2010 5

6. We Are Not AloneFrom 07 Sept to 07 Oct 2010 10/12/2010 6 DengueMap, HealthMap.

7. 10/12/2010 7 KNOW DO GOAL

8. Aedes aegypti and Aedes albopictus The vector 10/12/2010 8

9. The Mozzies Yellow Fever Dengue Chikungunya West Nile Virus Malaria 10/12/2010 9

10. Question 10/12/2010 10 What does “aedes” mean? “Unpleasant” (Greek) by Meigen in 1818

11. Life Cycle All in all, it takes 8-10 days. Two phases: terrestrial and aquatic Eggs are resistant to environmental stress. Eggs  larva (feeder) in presence of water Larva  pupa (non-feeder) Pupa  young adult (still water) “The Mosquito Life-cycle,” Centers for Disease Control and Prevention 10/12/2010 11

12. Feeding Mosquitoes sense the presence of: Genetics – 85% Chemicals (respiratory, skin) Carbon dioxide (activity, using candle) Lactic acid (exercise, after eating salty foods, high-potassium) Steroids Uric acid Cholesterol Pregnancy Body temperature Dark-colored materials clothings, garbage cans Movement Floral/fruity fragrances Moisture 10/12/2010 12

13. Question 10/12/2010 13 Why do female mosquitoes need blood? For egg development. The amino acid isoleucine is important.

14. Breeding 10/12/2010 14 Mosquitoes will practically breed anywhere where there is a collection of water that stands longer than five to seven days. Some prefer lighted areas and some shady areas. Some prefer fresh water and some stagnant water.

15. 10/12/2010 15 Ponds Streams Swamps Common natural breeding grounds Rock holes Tree holes Ditches

16. 10/12/2010 16 Rain barrel Cans Wells Common man-made breeding grounds Vases Roof gutter Old tires Road gutter

17. Comparison Aedes aegypti Aedes albopictus 10/12/2010 17 “Invasion biology of Aedes albopictus,” University of Florida.

18. Aedes aegypti Aedes albopictus Egyptian tiger mosquito Origin: Africa Primary vector for: Yellow fever Dengue fever Chikungunya fever Prefers to breed in water storage containers (in and out) Day biter  humans Asian Tiger mosquito Origin: Africa/S.E. Asia Vector for: Same as aegypti Prefers to breed in trash (out) Outdoor day biter  humans, livestock, amphibians, reptiles, and birds “Larval habitats and distribution patterns of Aedes aegypti and Aedes albopictus in Thailand,” Chareonviriyaphap, et al., 2003. PDF Aedes albopictus, Global Invasive Species Database. 10/12/2010 18

19. Question 10/12/2010 19 In the Philippines, which of the two is the predominant mosquito specie? Aedes aegypti

20. Dengue Virus The causative agent 10/12/2010 20

21. The Dengue Virus 10/12/2010 21 Flavivirus (Yellow virus) Only transmitted by mosquito bites It takes 8 days for a mosquito to be a vector but remains infected for life. Dengue 1 Virus and Dengue Hemorrhagic Fever, French Polynesia, 2001, Hubert and Halstead, Emerging Infectious Diseases, August 2009

22. Historical Dengue viruses originally came from monkeys. It jumped to humans 100 to 800 years ago. It was a minor disease until World War 2 10/12/2010 22

23. Question 10/12/2010 23 Why has dengue became a significant health problem after World War 2? Due to increased travel and active transport industry

24. The Four Types Dengue has four closely related types or serotypes: DENV-1 to 4 Each serotype gives specific lifetime immunity and short-term cross-immunity. A second, third or fourth infection results in a worse infection than the first. Infants can have a severe first infection if the mother has previous dengue infection. 10/12/2010 24 “Molecular Evolutionary Pathogenesis of Dengue Virus Infection,” Shannon Bennett

27. Dengue Fever, Dengue Hemorrhagic Fever The disease 10/12/2010 27

28. Question 10/12/2010 28 Where did the word “dengue” come from? Spanish, “dengue” for “fever” Swahili, “Ka-dinga pepo” for “sudden cramp-like illness caused by an evil spirit.”

29. Historical Reports Chronology 265-420 AD in China; called “water poison” Slaves in Caribbean, “Dandy fever” 1780 in Madras, India and Philadelphia, USA 1789, Benjamin Rush coined the term “breakbone fever” 1799 in Cairo and Alexandria, Egypt; Jakarta, Indonesia1943: Japanese scientists first identified the virus 1953: First report of Dengue Hemorrhagic Fever in Manila 1956: Four types of dengue 10/12/2010 29 Number of cases vs. number of countries 1955-2007

30. 10/12/2010 30 Dengue virus infection With symptoms No symptoms Dengue Fever (DF) Syndrome No different from other fever Dengue Hemorrhage Fever (DHF) (plasma leakage) Symptoms: Sudden rise in temperature, facial flush, DF symptoms like vomiting, headache, etc., sore throat, gum bleeding, breathlessness, elevated blood hematocrit With unusual hemorrhage Symptoms: high fever; severe headache; pain behind the eyes; muscle, bone and joint pains; nausea, vomiting, and rash. Skin hemorrhage (tiny purplish-red spots on skin) sometimes seen Without hemorrhage No shock Dengue Shock Syndrome Symptoms: Occurs at the end of fever on 3rd to 7th day, skin becomes cool and blotchy, pulse weak and rapid, lethargy, restlessness, acute abdominal pain frequently felt just before onset of shock Dengue Fever Dengue Hemorrhage Fever http://thestar.com.my/archives/2008/9/14/health/sf_pg06manifestation.jpg

31. Dengue or not? Diagnosis: Medical history Physical examination Tourniquet test Lab: Low platelet count (<150,000) Complete blood count/hematocrit Blood test for antibodies 10/12/2010 31

32. Managing Dengue What to do Bring the fever down. Sponge bath and paracetamol. Maintain hydration using oral fluids. Keep mosquitoes away. Use mosquito nets. What Not to do Avoid certain drugs like aspirin, NSAIDs (ibuprofen, mefenamic acid) Avoid IV fluids. Use oral fluids if child is able to drink. Fluids in the lungs Water retention 10/12/2010 32

33. Warning Signs of DHF 10/12/2010 33 Critical Period: Risk for DHF is high 1-2 days after fever subsides. Refuse fluids or vomiting. Sleepy or restless child. Gastrointestinal bleeding Abdominal pain Skin mottling, cold sweaty skin, cold hands and feet No urine for the past 6 hours. Mottled skin dehydration GI bleeding Abdominal pain

34. Dengue Hemorrhagic Fever (DHF) Causes of death Shock due to dehydration Severe hemorrhage Encephalitis Liver failure Odds of getting DHF? DHF is a second infection. 90% of DHF patients has previous infection. Getting a second infection does not mean you’re going to get DHF Risk of dying from DHF with inadequate treatment is 10%-15% Risk of dying from DHF with adequate treatment is < 1% 10/12/2010 34 Advice to former dengue patients Don’t get bitten again!

35. Barriers Against Mosquito Bites and Infection Preventing dengue 10/12/2010 35

36. Mosquito Repellents DEET Apply insect repellent DEET(20-30%) If repellent is aerosol, open air If child, don’t apply to hands Apply on clothing. Mosquito net if room is non-air-conditioned or screened Natural Need frequent application Citronella, lemon eucalyptus, castor oil, peppermint oil. Multiple repellents tend to be more effective due to mosquito differences. 10/12/2010 36

37. Prevent Breeding 10/12/2010 37 4 Cover up tires before disposal to prevent water from collecting. 1 2 Change the water in vases and for aquatic plants at least once a week and leave no water in the saucers underneath the plants Keep drains free from blockage Cover water containers, wells, and water tanks tightly 3 Check whether there is water collecting on the tray under an air-conditioner and in the drainage system, and remove stagnant water Dispose of unwanted containers where water may collect such as lunch boxes and soft drink cans into covered bins 5 7 6 Repair uneven surfaces of the ground to prevent water from collecting Let’s Act to Prevent Dengue, Hong Kong Housing Authority

38. Prevent Bites 10/12/2010 38 3 Use mosquito nets or screens when the room is not air-conditioned 1 Wear light-coloured and long-sleeved clothing and pants 2 Apply mosquito repellents containing DEET to exposed parts of the body Install screens on windows and doors, or place mosquito coils /electric mosquito mats /anti-mosquito liquid near the windows 5 4 Avoid visiting scrubby areas

39. Vaccines? At present, there are no approved vaccines. At the US National Institute of Health, 11 vaccines are undergoing testing. Difficulties with vaccine development: Four serotypes with no cross-immunity. No good animal model for testing. Vaccines should be tetravalent  against the DENV-1 to 4 10/12/2010 39

40. 10/12/2010 40 Dengue Hemorrhagic Fever: Early Recognition, Diagnosis and Hospital Management Click the image below to view video from your browser.

41. Websites of Interest dengue References 10/12/2010 41

42. Wikipedia 10/12/2010 42 http://en.wikipedia.org/wiki/Dengue_fever

43. Centers for Disease Control and Prevention 10/12/2010 43 http://www.cdc.gov/Dengue/

44. Dengue Map 10/12/2010 44 http://www.healthmap.org/dengue/index.php

45. Center for Health DevelopmentCentral Visayas 10/12/2010 45

46. This Week in Virology 10/12/2010 46