Dr Balvinder Singh Gill, PhD Disease Control Division Ministry of Health Malaysia VECTOR BORNE DISEASE SURVEILLANCE IN MALAYSIA
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Dr Balvinder Singh Gill, PhD
Disease Control Division
Ministry of Health Malaysia
VECTOR BORNE DISEASE SURVEILLANCE IN MALAYSIA
TYPES OF VECTOR BORNE SURVEILLANCE SYSTEMS
TYPES OF VECTOR BORNE SURVEILLANCE SYSTEMS
Disease Trends
Cases vs Deaths
Notifications (suspected) vs Registered (Confirmed) vs Hospital admissions
Case confirmation
2008 – 49,355 cases
2012 - 21,900 cases
2013 – 43,346 cases
2014 – 108,698 cases
2015 – 89,744 cases(upto 26 September - Week 38)
DISEASE TRENDS - REGISTERED DENGUE CASES IN MALAYSIA BY YEAR, 1973 - 2015
CASES VS DEATHS - DENGUE CASES AND DEATHS IN MALAYSIA, 2000 - 2015
DENGUE CASE NOTIFICATION AND REGISTRATION IN MALAYSIA, 2009 - 2013
DENGUE CASE NOTIFICATION, REGISTRATION AND ADMISSION IN MALAYSIA, 2009-2011
Laboratory diagnosis of DENV infection can be made by serological and molecular methods for the detection of the viral antigen, or antibodies.
Various approaches used in dengue diagnosis are dependent on the timing of sample collection with respect to symptoms and development of immune responses during the course of the infection
LABORATORY DIAGNOSIS OF DENGUE
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In 2012, day 4 was highest with 4,502 (20.6%) cases notified. By Day 5 from the onset of symptoms, 72.4% of cases were notified.
DAYS BETWEEN ONSET AND NOTIFICATION OF DENGUE CASES IN MALAYSIA, 2012
From Day 1 to 4 from the onset of symptoms, NS1-ELISA had a total of 173/306 (56.6%) positive cases compared to 108/306 (35.3%) for
IgM-ELISA. This accounted for an additional 65 (21.2%) positive cases.
However from Day 5 onwards, IgM-ELISA was higher with 81/203 (39.9%) positive cases compared to 55/203 (12.8%) for NS1-ELISA,
this accounted for an additional 55 (27.1%) positive.
EVALUATION OF DENGUE DIAGNOSTIC METHODS IN MALAYSIA, 2010
There were a total of 27 samples tested positive for chikungunya and 10 samples that were tested positive for Leptospirosis.
Hence, of the total samples tested, 29.2% samples were positive for dengue, 9.2% were positive for Chikungunya and 3.4% were positive
for Leptospirosis. 58.2% were negative for any of the tests conducted.
DISTRIBUTION OF DENGUE, CHIKUNGUNYA AND LEPTOSPIROSIS IN MALAYSIA, 2010
DENGUE CASE NOTIFICATION AND REGISTRATION IN MALAYSIA, 2014 – 2015
TYPES OF VECTOR BORNE SURVEILLANCE SYSTEMS
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CIRCULATING DENGUE SEROTYPES IN MALAYSIA, 1990 – 2010
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DENGUE CASES AND CIRCULATING SEROTYPES IN MALAYSIA, 2013 - 2015
DISTRIBUTION OF DENGUE SEROTYPES IN MALAYSIA, 2005 - 2010
TYPES OF VECTOR BORNE SURVEILLANCE SYSTEMS
DENGUE CASES AND PREMISES INDEX IN SINGAPORE, 1966 - 2005
TYPES OF VECTOR BORNE SURVEILLANCE SYSTEMS
There were a total of 27 samples tested positive for chikungunya and 10 samples that were tested positive for Leptospirosis.
Hence, of the total samples tested, 29.2% samples were positive for dengue, 9.2% were positive for Chikungunya and 3.4% were positive
for Leptospirosis. 58.2% were negative for any of the tests conducted.
DISTRIBUTION OF DENGUE, CHIKUNGUNYA AND LEPTOSPIROSIS IN MALAYSIA, 2010
TYPES OF VECTOR BORNE SURVEILLANCE SYSTEMS
Monthly climate readings (rainfall (mm), mean temperature (°C), and average relative humidity (%))
collected from the 26 meteorological stations for the study period were converted from points into
surfaces that matched notification rates within the boundaries.
The inverse distance weighted (IDW) method was used to interpolate metrological data to obtain
values of these climate variables for the states studied.
The raster surface was layered on the geospatial shape files with the state boundaries and the
average value for all raster cells within the state boundary was calculated for each climate variable.
DENGUE – CLIMATE FACTORS
DENGUE – CLIMATE FACTORS - RAINFALL
In states of the west coast, peaks of dengue notification rates were generally seen in the months of
January and February which coincides with the NEM from November to March, while secondary peaks
were also seen during July to August, which in turn coincides with the SWM from May to September.
States in the west coast
Results of cross-correlations shows a negative relation between rainfall and dengue rates during the
current month and a positive cross-correlation was observed after a months lag for most states.
DENGUE – CLIMATE FACTORS - RAINFALL
States in the west coast States in the east coast
Heavy rains have a negative effect by flushing out of larval habitats of these mosquito vectors.
In addition, heavy rains accompanied by strong winds might disturb the flight activity of mosquito
vectors, resulting in difficulties to find hosts and suitable breeding sites, in turn decreasing the disease
activity.
This delay of a month between peak rainfall and the increase of dengue rates can be explained by the
time taken for the development of a mosquito larva, and the transmission cycles of the virus:
DENGUE – CLIMATE FACTORS - RAINFALL
Gubler DJ, Rosen L. A simple technique for demonstrating transmission of dengue virus by mosquitoes without the use of vertebrate hosts. American Journal of Tropical Medicine and Hygiene.
1976;25(1):146-50.
DENGUE – CLIMATE FACTORS - TEMPERATURE
A positive association between temperature peaks and dengue notification rates were seen at several
periods in the west coast states of Selangor and Negeri Sembilan.
States in the west coast
DENGUE – CLIMATE FACTORS - TEMPERATURE
These associations were strengthened by results of cross-correlations that demonstrated a positive
correlation between dengue notification rates and temperature at the current month for states in the
west coast.
States in the west coast
Focks DA, Haile DG, Daniels E, Mount GA. Dynamic life table model for Aedes aegypti (Diptera: Culicidae): simulation results and validation. Journal of Medical Entomology.
1993;30(6):1018-28.
Warmer temperatures contribute to increased adult mosquito survival
THE ECOLOGY OF DENGUE - TEMPERATURE
DENGUE – CLIMATE FACTORS – RELATIVE HUMIDITY
No clear pattern or similarities emerged in on the effect of relative humidity on dengue rates in any of
the states in this study.
THE CLIMATE AND DENGUE
TYPES OF VECTOR BORNE SURVEILLANCE SYSTEMS
DENGUE CASE NOTIFICATIONS AND REGISTRATIONS SOUTHERN STATES, 2011 – 2014
DENGUE CASE NOTIFICATIONS AND REGISTRATIONS CENTRAL STATES, 2011 – 2014
DENGUE CASE NOTIFICATIONS AND REGISTRATIONS WPKL AND SELANGOR, 2011 – 2013
DENGUE CASES JOHOR AND SINGAPORE, 2012 – 2013
TYPES OF VECTOR BORNE SURVEILLANCE SYSTEMS
THANK YOU
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