Epidemiology of Dengue in  Sri Lanka: past, present and future  Hasitha Tissera MBBS, MSc, MD Consultant Epidemiologist  M...
Outline  <ul><li>Background </li></ul><ul><li>Pre-endemic period  </li></ul><ul><li>Endemic period  </li></ul><ul><li>How ...
Dengue  <ul><li>Most important mosquito borne viral infection in the world  </li></ul><ul><li>Very common infection in tro...
Transmission Modulating Factors Vector Host  (human) Virus Dispersion Density Deposited eggs Vector’s competency Individua...
Dengue: Global burden  Dengue ploriferates from 20 th  to 21 st  century with increasing burden, despite a lot of hard wor...
Why Epidemiology ? <ul><li>To aid in setting health priorities  </li></ul><ul><li>To aid in setting research priorities </...
Pre-endemic History <ul><li>Clinical dengue-like illness from beginning of 20 th  century  </li></ul><ul><li>Serologically...
Endemic Period – 1989 onwards <ul><li>DHF became endemic in 1989* </li></ul><ul><li>1989 – 203 hospitalized with 20 deaths...
Temporal and Spatial Spread, 1996 - 2009 1996 2004 2005 2006 2009 N=1294 N=15463 N=5994 N=11980 N=35007 Reported Cases to ...
Dengue Trends in Sri Lanka 2009 CFR – 0.99% 2010 CFR – 0.71% 2011 CFR -  0.71%
2004 : 7 districts >100 2009 : 13 districts >100  Geographic Expansion  2004 - 2010  Incidence 80/100,000  Incidence 170/1...
Dengue cases by age groups Sri Lanka - 1996 and 2006 1996 No. of cases analysed N= 1125 Source: Epidemiology Unit Sri Lanka
Overall Sero-prevalence among children < 12  – 52%  study supported by PDVI
Seasonality  <ul><li>South-western monsoon peak: May – July  </li></ul><ul><li>North-eastern monsoon peak: Oct - Jan </li>...
What we did to control & prevent <ul><li>Vector control through awareness – until 2004 </li></ul><ul><li>With epidemic shi...
Where are we today <ul><li>In general to date , the  targeted health interventions largely not  sustainable, less effectiv...
WHY IS DENGUE SUCH A BIG PROBLEM TODAY? <ul><li>Global population growth </li></ul><ul><li>Rural to urban migration </li><...
Which Perspective Do We Take? SOCIETY PATIENT FAMILY GOVERNMENT ALL OTHER STAKE HOLDERS SCIENCE Slide courtesy of Dr. Anan...
National Plan: Outputs  <ul><li>Improved Case Management </li></ul><ul><li>Strengthened Surveillance – disease, laboratory...
Dengue Epidemiology  <ul><li>Primary Prevention: </li></ul><ul><li>Reduce disease transmission (interruption) – solidifyin...
Dengue Epidemiology…  <ul><li>Secondary Prevention:  </li></ul><ul><li>Early case detection – Iry care & pvt. sector throu...
Statistics LRH Ward 04 - 2009 Source: Infection Control Unit LRH + Ward 04 records  Slide courtesy of Dr. Padmakanthi Wije...
5,565 12,422 Source: Epidemiology Unit Data
Dengue Situation by Month 2011 2010 2009
To bring down mortality…  Scott B. Halstead, M.D. <ul><li>Providing Micro-haematocrit    Machines to Hospitals  </li></ul>...
 
 
Advocacy  - Highest Level  <ul><li>Health </li></ul><ul><li>Local Govt. </li></ul><ul><li>Environment </li></ul><ul><li>De...
High - risk areas  June  -  July 2011
Major Breeding Habitats  Urban Breeding Sites  Rural  Breeding Sites  Discarded containers  – plastic cups, tins, cans, bo...
www.epid.gov.lk <ul><li>Regular update on dengue situation  </li></ul>Thank You!
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Dengue Seminar September 2011

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The slides used in the presentation by the Sri-lankan team, at the Seminar at SIMS, Lahore.

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  • Being endemic for dengue with around 5000 cases per year since year 2000, epidemics have been reported during the rainy seasons once every 3-4 years. Along with the geographic expansion the incidence too has grown – with over 20 districts reporting more than 100 cases per 100,000 population in 2010. Reported national incidence has a marked upward trend. An incidence of 30/100,000 population in year 2000 has gone up to 170/100,000 population by 2009 (an increase of almost 6 times) and &gt;200/100,000 in 2010.
  • Sri Lanka has both childhood &amp; adult dengue
  • shows the number and percentage of children positive for flavivirus antibodies. Overall 51.4% (407) of children were seropositive. There was an increasing trend with age, from 7.4% (2) among infants between 6 and 12 months to 71.7% (38) by the age of 11 years. Among 25 infants &lt;6 months of age, 33.3% were seropositive, indicating that there is substantial acquisition of maternal antibodies among infants in this population.
  • Dengue is a quintessential 20-21 st century emerging disease. By 1960, Aedes aegypti had been largely eradicated from the American tropics but after abandoning vector control programs, the mosquito quickly returned. Viral infections were accelerated by the demographic forces described in this slide.
  • We are experiencing more and more severe form of the disease.
  • Dengue has undoubtedly become the most important public health concern in Sri Lanka at present. And it has received the highest political commitment. Last week (on May 25 th ) a Presidential Task Force was set-up involving 8 ministries with a mandate to control dengue through strengthened intersectoral collaboration.
  • Dengue Seminar September 2011

    1. 1. Epidemiology of Dengue in Sri Lanka: past, present and future Hasitha Tissera MBBS, MSc, MD Consultant Epidemiologist Ministry of Health Epidemiology Unit Ministry of Health Sri Lanka Dengue Seminar September, 2011
    2. 2. Outline <ul><li>Background </li></ul><ul><li>Pre-endemic period </li></ul><ul><li>Endemic period </li></ul><ul><li>How we could change the epidemiology </li></ul>
    3. 3. Dengue <ul><li>Most important mosquito borne viral infection in the world </li></ul><ul><li>Very common infection in tropics </li></ul><ul><li>Large epidemics occur </li></ul><ul><li>Nearly 90% of infections in children </li></ul><ul><li>Wide spectrum of infection outcomes </li></ul><ul><li>Asymptomatic infection -> Death </li></ul><ul><li>High morbidity, relatively low mortality disease </li></ul>
    4. 4. Transmission Modulating Factors Vector Host (human) Virus Dispersion Density Deposited eggs Vector’s competency Individual immnunity Herd immnunity Sequential Infections Individual factors Magnitude of the Epidemics (DF/DHF) Serotypes (Previous Circulation) Genetic differences Virulence Probability of Transmission Source: Prof. Maria Gloria Teixeira, London May 2008
    5. 5. Dengue: Global burden Dengue ploriferates from 20 th to 21 st century with increasing burden, despite a lot of hard work on control and prevention 1960 2004
    6. 6. Why Epidemiology ? <ul><li>To aid in setting health priorities </li></ul><ul><li>To aid in setting research priorities </li></ul><ul><li>To identify prospective health interventions </li></ul><ul><li>To provide a comparable measure of output for interventions </li></ul>
    7. 7. Pre-endemic History <ul><li>Clinical dengue-like illness from beginning of 20 th century </li></ul><ul><li>Serologically confirmed in 1962 </li></ul><ul><li>First outbreak in 1965 </li></ul><ul><li>D1-D4 circulating since at least 1966 </li></ul><ul><li>1965-68 had 51 cases and 15 deaths </li></ul><ul><li>1969 – 88’ multiple outbreaks of DF with occasional DHF </li></ul><ul><li>Mostly from Western Province </li></ul><ul><li>School cohort study 1980-85’ (pre DHF): Dengue sero- prevalence 50% (7000, 5-7 year olds in Colombo MC) </li></ul>
    8. 8. Endemic Period – 1989 onwards <ul><li>DHF became endemic in 1989* </li></ul><ul><li>1989 – 203 hospitalized with 20 deaths (CFR 9.8%) </li></ul><ul><li>1990 – sharp increase to 1300 cases and 54 deaths (CFR 4%) </li></ul><ul><li>1991- 95’ – multiple outbreaks </li></ul><ul><li>1996 – became nationally notifable disease </li></ul><ul><li>*Source: Vitarana T, Jayakuru WS and Withane N, Ministry of Science Technology and Human Resources, 1993 </li></ul>
    9. 9. Temporal and Spatial Spread, 1996 - 2009 1996 2004 2005 2006 2009 N=1294 N=15463 N=5994 N=11980 N=35007 Reported Cases to National Epidemiological Unit
    10. 10. Dengue Trends in Sri Lanka 2009 CFR – 0.99% 2010 CFR – 0.71% 2011 CFR - 0.71%
    11. 11. 2004 : 7 districts >100 2009 : 13 districts >100 Geographic Expansion 2004 - 2010 Incidence 80/100,000 Incidence 170/100,000 2010 : 21 districts >100 Incidence 170/100,000 2004 2009 2010
    12. 12. Dengue cases by age groups Sri Lanka - 1996 and 2006 1996 No. of cases analysed N= 1125 Source: Epidemiology Unit Sri Lanka
    13. 13. Overall Sero-prevalence among children < 12 – 52% study supported by PDVI
    14. 14. Seasonality <ul><li>South-western monsoon peak: May – July </li></ul><ul><li>North-eastern monsoon peak: Oct - Jan </li></ul>South-west monsoon North-east monsoon
    15. 15. What we did to control & prevent <ul><li>Vector control through awareness – until 2004 </li></ul><ul><li>With epidemic shift in 2004: </li></ul><ul><li>- Active social mobilization </li></ul><ul><li>- Aggressive vector control </li></ul><ul><li>- Attempt improvement in clinical management </li></ul>
    16. 16. Where are we today <ul><li>In general to date , the targeted health interventions largely not sustainable, less effective than expected. Why? </li></ul><ul><li>A few model countries on effective surveillance (Brazil), Vector control (Singapore, Cuba) and effective clinical management (Thailand, Vietnam) exist, but are exceptions . </li></ul>
    17. 17. WHY IS DENGUE SUCH A BIG PROBLEM TODAY? <ul><li>Global population growth </li></ul><ul><li>Rural to urban migration </li></ul><ul><li>Growth of cities </li></ul><ul><li>Deterioration of cities </li></ul><ul><li>Jet travel </li></ul><ul><li>Health services poorly organized/ underfunded </li></ul><ul><li>Lack of vector control professionals </li></ul>Slide courtesy of Dr. Scott Halstead
    18. 18. Which Perspective Do We Take? SOCIETY PATIENT FAMILY GOVERNMENT ALL OTHER STAKE HOLDERS SCIENCE Slide courtesy of Dr. Ananda Amarasinghe
    19. 19. National Plan: Outputs <ul><li>Improved Case Management </li></ul><ul><li>Strengthened Surveillance – disease, laboratory, entomological </li></ul><ul><li>Capacity building – at all levels infrastructure, staff, equipment, </li></ul><ul><li>Strengthened control activities at National, Provincial, District, & Divisional levels </li></ul><ul><li>Enhanced intersectoral & community participation for sustainable programme </li></ul>
    20. 20. Dengue Epidemiology <ul><li>Primary Prevention: </li></ul><ul><li>Reduce disease transmission (interruption) – solidifying evidence based vector control approach; </li></ul><ul><li>- improved entomological assistance </li></ul><ul><li>- adult vector control </li></ul><ul><li>(B) Vaccine – preparation for vaccine introduction when become available (earliest 2015) – need to plan now </li></ul>
    21. 21. Dengue Epidemiology… <ul><li>Secondary Prevention: </li></ul><ul><li>Early case detection – Iry care & pvt. sector through improved diagnostics: </li></ul><ul><li>- Full Blood Count </li></ul><ul><li>- NS1 (cost implications) </li></ul><ul><li>(B) Improving Clinical Management </li></ul><ul><li>- reducing disease severity </li></ul><ul><li>- reducing case fatality </li></ul>National Guidelines 2010
    22. 22. Statistics LRH Ward 04 - 2009 Source: Infection Control Unit LRH + Ward 04 records Slide courtesy of Dr. Padmakanthi Wijesuriya, Consultant Paediatrician LRH DF DHF I & II DHF III DHFIV Total Dengue Patients : 333 (Jan-Aug 2009)
    23. 23. 5,565 12,422 Source: Epidemiology Unit Data
    24. 24. Dengue Situation by Month 2011 2010 2009
    25. 25. To bring down mortality… Scott B. Halstead, M.D. <ul><li>Providing Micro-haematocrit Machines to Hospitals </li></ul><ul><li>Setting up of National ‘Hotline’ </li></ul><ul><li>Standardized teaching and training curricula at all levels </li></ul>
    26. 28. Advocacy - Highest Level <ul><li>Health </li></ul><ul><li>Local Govt. </li></ul><ul><li>Environment </li></ul><ul><li>Defense </li></ul><ul><li>Education </li></ul><ul><li>Media </li></ul>
    27. 29. High - risk areas June - July 2011
    28. 30. Major Breeding Habitats Urban Breeding Sites Rural Breeding Sites Discarded containers – plastic cups, tins, cans, bottles.… Discarded containers – coconut shells, clay pots, bottles …. Water Storage –tanks, barrels, buckets Water storage – tanks, barrels, buckets Used Tyres - domestic, workshops, depots Used Tyres – domestic, workshops, depots Roof Gutters - domestic, offices, high-rising building tops Roof Gutters – domestic, sun shades Other – ornamental items, blocked drains, construction sites, natural breeding -ornamental plants, underprivileged communities, bare lands Other – spare part yards, natural breeding sites -bamboo shoots, tree axills/holes, fallen tree leaves, plantations
    29. 31. www.epid.gov.lk <ul><li>Regular update on dengue situation </li></ul>Thank You!

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