1. Surveillance, Disease Control and Prevention for Chikungunya Fever Thailand, 2008-2009 Rome Buathong, MD., FETP. Central Epidemiological Investigation and Surveillance Bureau of Epidemiology Thailand-Ministry of Public Health BUREAU OF EPIDEMIOLOGY-Ministry of Public Health (MOPH), THAILAND

2. Arthropod-borne viral arthritis and rash syndrome consist of –Chikungunya virus disease –Mayaro virus disease –Sindibis virus disease –O’nyong-nyong Fever: less arthritis Chikungunya virus disease เป็น RNA virus จัดอยู่ใน Alphavirus gunus, Togaviridae family Chikungunya Infection

3. Three strains were distinguished –East/Central African Strain –West African Strain –Asian Strain Aedes aegypti ( ยุงลายบ้าน ), Aedes albopictus ( ยุงลายสวน ) are main vector Chikungunya Infection

4. East/Central African Strain West African Strain Asian Strain

5. Singapore (Jan 08) 200 Malaysia (Sep 08) 2,000 India, ~1,500,000 cases Report ~200 death cases

6. BUREAU OF EPIDEMIOLOGY-MOPH, THAILAND 1976 Prachinburi 1958, First identified in Bangkok 1988 Surin 1991 Khon Khean 1993 Loei, Phrayao 1995 Nongkhai(94), Nakhon Si Thammarat(576) History of Chikungunya Fever in Thailand Chikv strain identified in 1962-1995 was all Asian strain (AFRIMS)

7. Yi-ngo อ.ยี่งอ In October, 2008 Cluster of fever, rash and severe arthralgia was detected in one village at Laharn health center and then chikungunya was suspected After investigation among 82 suspected case revealed positive Chikungunya by RT-PCR and seroconversion by HI (60%)

8. Background  Since Chikungunya fever was not a notifiable disease in Thailand, thus the Bureau of Epidemiology included Chikungunya fever is the latest notifiable disease and launched in November 2008 (passive surveillance nationwide; all gov. hospitals and some private)  Three case definitions were described as suspected, probable and confirmed  All suspected cases required to retrospective report to the national surveillance system BUREAU OF EPIDEMIOLOGY- MOPH, THAILAND

9. Case Definitions  Suspected Case: Fever with at least two of the following symptoms 1.Arthralgia/Arthritis/Joint swelling 2.Rash 3.Myalgia 4.Headache 5.Retro-orbital pain  Probable Case: suspected case with 1) PLT normal and WBC < 5000 or 1) PLT normal and WBC < 5000 or 2) Epi-linkage with confirmed case 2) Epi-linkage with confirmed case  Confirmed Case: suspected case with CHIKV laboratory confirmed by PCR, HI a/o IgM BUREAU OF EPIDEMIOLOGY- MOPH, THAILAND

10. Protocol for Lab Testing BUREAU OF EPIDEMIOLOGY- MOPH, THAILAND A Suspected Chikungunya Fever Epidemic area Chikungunya ( NIH) 1.RT PCR ( onset < 5 days) 2.HI ( 2-3 weeks a part) Dengue(NIH) 1.HI ( 2-3 weeks a part) Other area Same as epidemic area PLUS 1.Measles IgM (NIH) 2.Rubella IgM (NIH) Entomology Mosquito trapping: Human base technique Aspirator technique Isolated CHIKV: at AFRIM and NIH Molecular sequencing: at AFRIM and NIH (both human & mosquito) Identified Aedes spp.: at AFRIM and NIH

11. Surveillance Results  By March 10 th, 2009, totally 12,115 suspected cases were reported to the passive surveillance system with no death case  Male : female ratio was 1:1.5  Adult cases was 86%  Median age was 38 years (IQR: 23, 50)  The main occupation was agricultural (47%)  The OPD:IPD:Active cases ratio was 15:1:1 BUREAU OF EPIDEMIOLOGY-MOPH, THAILAND

12. Number of Cases by Date of Onset, Chikungunya Fever, Thailand August 2008-March 2009 BUREAU OF EPIDEMIOLOGY-MOPH, THAILAND N=12,115 X-sectional serosurvey was conducted in one village (n=521) 26% seropositive by IgM ( ≥ 40 units) & HI ( ≥1:40), 10% Asymptomatic infection, Adult spec. AR = 29% vs Children spec. AR=7% (p<0.001)

13. Narathiwat, 6371 cases 890/100,000 pop. Pattani, 1612 cases 251/100,000 pop. Yala, 488 cases 103/100,000 pop. Songkhla, 3629 cases 272/100,000 pop. Aug 11 th,08 Sep 10 th,08 Oct 12 th,08 Nov 1 st,08

14. Laboratory Results BUREAU OF EPIDEMIOLOGY-MOPH, THAILAND   Totally 1,009 cases were sent for laboratory testing for CHIKV (Jan 31 st, 09)   492 cases were laboratory confirmed (48.8%) either RT-PCR or sero-conversion for HI (four-fold rising)   The yield of RT-PCR for CHIKV was 58.0%(457/788) and sero-conversion HI was 47.9% (114/238)   Dengue was positive 4.3% (43/1009)

15. BUREAU OF EPIDEMIOLOGY-MOPH, THAILAND Chikungunya Suspected Confirmed Chikungunya Fever 50% Dengue 4% Rubella <1% Measles <1%

16. Entomology BUREAU OF EPIDEMIOLOGY-MOPH, THAILAND   Aedes albopictus and Ae. aegypti were identified in epidemic setting of deep southern part of Thailand   CHIKV was isolated by PCR in both species of Aedes spp.   Molecular sequencing is pending

17. BUREAU OF EPIDEMIOLOGY-MOPH, THAILAND SRRT, 1030 nation wide Within 24 hr, Early control and containment PCR/IgM

18. Prevention & Control Strategies BUREAU OF EPIDEMIOLOGY-MOPH, THAILAND   Early detection – clinical criteria and laboratory testing especially in new area   Early investigation and control immediately   National campaign for mosquito larva eradication (as much as possible)   Health education   Nationwide: TV, internet, printing media   Local: community radio

19. BUREAU OF EPIDEMIOLOGY-MOPH, THAILAND   Contagious spreading as a majority   Sporadic cases were detected in non-epidemic area   All cases associated with southern epidemic area   Imported by travelers; students, military recruits   No sustainable local transmission   Active surveillance in nursing colleges, military units, transportation terminals in BKK

20. East/Central African Strain Islands in Indian Ocean, India, Srilangka, Malaysia, Thailand 2008-2009 Mutation of E1 gene at Position 226 change from Alanine to Valine ( 226 A  226V)

21. Molecular Sequencing of Chikungunya virus in human E1 226V

22. Update Laboratory Diagnosis NIH –HI titer : 4-fold rising in paired –Rapid test IgM: no longer interpretation –IgM will be available in OD cut point –PCR ( only RT) is the best –Viral isolation  Sequencing AFRIM –PCR ( RT, Nested and real time)  sequencing –IgM by ELISA ( unit) : > 40 units –HI titer –Virus isolation

23. Significant Finding in Serosurvey Study at Village no 8, Laharn Sub-district, Yi-Ngor District, Narathiwat 2008 Pisittawoot Ayood, MD. FETP. Bureau of Epidemiology Department of Disease Control Ministry of Public Health

24. Results Overall survey 698 people (~ 750 pop) Totally 480 people were blood drawn Blood testing for IgM and HI at AFRIM and NIH –IgM ≥ 40 units => Acute infection –HI titer ≥ 1:40 => Recent infection Totally 117 cases was met seropositive criteria (24.4%) Median age: 53 years, Range (4-87), IQR (43- 65) Number of children case was only 6 (5%) Male : female ratio was 1:1 (58:59)

25. Symptom Vs. Asymptom in Confirmed Chikungunya Infection N=117

26. Clinical Presentation of Symptomatic Confirmed Chikungunya Infection N = 78

27. Clinical Case Definition compare to Laboratory Confirmed Chikungunya Infection as a Gold Standard Case Definition Fever + 1 Clinical Fever + 2 Clinical Any + 3 Clinical Sensitivity76.5%54.7%79.0% Specificity88.1%95.3%87.6% Predictive Value Positive (PVP) 60.7%79.0%58.1% Predictive Value Negative (PVN) 93.9%86.7%95.1%

28. Clinical Presentation of Symptomatic Confirmed Chikungunya Infection Among 78 symptomatic confirmed cases –Fever + joint symptom (pain or swelling):79.5% –Fever + joint pain: 78.2% –Fever + rash: 57.7% –Fever + joint symptom + rash: 52.6%

29. Conclusion BUREAU OF EPIDEMIOLOGY-MOPH, THAILAND   The re-emerging Chikungunya fever is confirmed after the 13-year absence with new strain   The outbreak tends to spread out in the adjacent provinces (one month apart)   Few confirmed cases were reported from other parts of the country (with related to southern area)   The vector control measures were limited in this complicated situation area with high density of both species of Aedes mosquito circulation   The major interventions include early case detection by clinical criteria and then laboratory testing with PCR, rapid investigation and implementation of control measures

30. Contributions BUREAU OF EPIDEMIOLOGY-MOPH, THAILAND   Department of Disease Control   Department of Medical Sciences   Department of Medical Services   Offices of Permanent Secretary   Medical Schools/Universities   Royal College of Physician and Pediatrics of Thailand   Ministry of Defense   AFRIMS MOPH

31. BUREAU OF EPIDEMIOLOGY- MOPH, THAILAND SAWASDEE THAILAND Thank you for your attention