Dengue Seroepidemiology in India.

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Dengue Seroepidemiology in India.
Rohit Arora, Sanofi Pasteur
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Dengue in the Past Quarter

• This map may be used as a guide for the
  assessment of dengue risk throughout the world.
  The blue regions represent areas of ongoing
  transmission risk as defined by the Centers for
  Disease Control and Prevention (CDC) based on
  data from Ministries of Health, international
  health organizations, journals, and knowledgeable
  experts (last updated in 2010 for the 2012 CDC
  Yellow Book). Recent reports (e.g., official,
  newspaper, other media) of local and regional
  dengue or imported cases of dengue collected by
  HealthMap are shown as red markers linked to the
  respective reports.

http//www.healthmap.org/dengue/index.php .
Accessed on 22/1/2012
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Dengue Seroepidemiology in India
Decade wise circulation of various serotypes of
Dengue in published literature
All 4 serotypes of Dengue have been known to
circulate in the country since many decades.
Chakravarti A,, Arora R, Luxemberger S. Fifty
years of dengue in India. Transactions of the
Royal Society of Tropical Medicine (Under Review)
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Active surveillance estimates of under reporting
in SEA countries
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Under-reporting Large Scale, Multi-year School
based Active surveillance for Dengue in Southern
Vietnam

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Surveillance estimates of under reporting of
Dengue in India

• Although Dengue is a notifiable disease, but
  there is still a significant factor of
  under-reporting.
• It is often difficult to estimate the true factor
  of under-reporting which may hugely vary due to
  differential access to healthcare infrastructure.
  
• This is compounded further by the non-regulated
  private healthcare setup where a substantial
  number of cases go unreported.

Transactions of the Royal Society of Tropical
Medicine and Hygiene (2008) 102, 570577
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Community-based dengue surveillance in India
(DNG09)

• Principal Objectives
• To estimate the population-based incidence of
  symptomatic laboratory-confirmed dengue
  infections in the catchment population of
  selected cohorts across India (associated with
  community centers)
• Study design
• Prospective epidemiological study.
• Sample size
• During the determined period of data collection,
  all patients presenting to the study sites and
  fulfilling the inclusion criteria described below
  will be enrolled.
• Dengue Confirmation
• Detection of dengue viral RNA by
  reverse-transcriptase polymerase chain reaction
  (RT-PCR) will be performed in acute blood sample.
• Serology by (ELISA) for IgG and IgM dengue
  antibody.

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The Challenges.

• Significant lack of population-based estimates of
  incidence of laboratory confirmed dengue
  infection.
• Even areas with confirmed dengue reports and high
  risk levels based on socio-demographic factors
  have no documented data.
• A retrospective investigation of morbidity data
  in GIS mapped outbreak area revealed that dengue
  was never diagnosed in any of the health centres.
• Given this lack of previous accurate
  documentation of dengue, a seroprevalence study
  was planned
• to assess the prevalence of dengue-specific
  antibodies which will allow assessing if there
  has been dengue transmission in the community in
  recent years.

2007
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Prospective dengue seroprevalence study in 5 to
10 year-old children in India.

• Most frequent diagnosis in these centres has been
  of
• Acute Respiratory Infection (ARI), and except the
  respiratory signs, the other ARI symptoms (e.g.
  fever, muscle aches, headache) are compatible
  with a possible diagnosis of dengue.
• A seroprevalence study was proposed, in a sample
  of children registered in the health centres
• to assess the prevalence of dengue-specific
  antibodies which will allow assessing if there
  has been dengue transmission in the community in
  recent years (5 years).
• Seroprevalence in children age between the age of
  5 to10 shall be able to provide insight into
  approximate average annual incidence of new
  dengue infection over the last 5-10 years.
• It was thought to additionally analyze
  JE-specific antibodies in this population
• To determine exposure of the Japanese
  Encephalitis Virus (Flavivirus) in this
  non-endemic area with close migratory connections
  with endemic zones (eastern UP)

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Prospective dengue seroprevalence study in 5 to
10 year-old children in India.

• Primary Objective
• To determine the prevalence of specific
  antibodies (IgG) against dengue in healthy 5 to
  10 year old children in India through IgG testing
  using the commercially available kit "EL1500G"
  from Focus Diagnostics (California, US)
• Secondary Objective(s)
• To determine the dengue virus serotype
  (DENV-1,2,3 and/or 4) specific to the antibodies
  in positive (IgG) samples through PRNT50
• To estimate the prevalence of specific antibodies
  (IgG) against Japanese encephalitis in healthy 5
  to 10 year-old children in India through JE IgG
  antibodies testing though Indirect ELISA using
  commercial available kits (InBios, USA)

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Prospective dengue seroprevalence study in 5 to
10 year-old children in India.

• Source and study population
• Children, 5 to 10 years of age, in India.
• Initially 2 study sites in Delhi. Is being
  progressively be expanded to 10 sites across
  India
• For the two study site in Delhi, the population
  is being drawn from children registered in health
  centres invited to participate during household
  visits performed by social workers of the health
  centres.
• Delhi Gate (Centre 001)
• Balmiki Basti (Centre 002)
• Dengue and JE antibodies testing is being
  conducted in Department of Microbiology at
  Maulana Azad Medical College, Delhi (Dr. Anita
  Chakravarti)

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Prospective dengue seroprevalence study in 5 to
10 year-old children in India.

• Sample size and power calculation
• This study is descriptive and therefore no
  hypothesis is being tested. The sample has been
  arbitrarily set at 323 subjects in each site.
• Assuming a prevalence rate of 30, a sample of
  323 subjects will ensure a precision of 5 for
  the 2-sided 95 confidence interval around the
  seroprevalence point estimate.

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THANKS