Geographical Information System in Lymphatic Filariasis

8/6/2019 Geographical Information System in Lymphatic Filariasis

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GEOGRAPHICAL INFORMATION SYSTEM IN

LYMPHATIC FILARIASIS

Bala Sakthi Janani.M


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Geographic Informatics

}Geographic Informatics is the science andtechnology of gathering, storing,analyzing, interpreting, modeling,distributing and using spatially referenced(georeferenced) information.

}Geographic Informatics is multidisciplinaryby nature and comprises a broad range ofdisciplines, including surveying and

mapping, remote sensing, geographicalinformation systems (GIS), and the GlobalPositioning System (GPS).


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GIS: a formal definition

A system for capturing, storing,

checking, integrating, manipulating,analysing and displaying data whichare spatially referenced to theEarth. This is normally considered

to involve a spatially referencedcomputer database and appropriateapplications software


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DigitalDigital

MappingMapping

PhotoPhoto--

grammetrygrammetry

ComputerComputer

AidedAided

DesignDesign

SurveyingSurveying

RemoteRemote

SensingSensing

DatabasesDatabases

GISGIS

Cross-disciplinary nature of GIS


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GIS components

Specific applications /decision making objectives

??

G IG I

Spatialdata

ComputerComputer hardware //software toolssoftware tools


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Spatial data storage

}Vector model

}Raster model

point

1,6

2,5

5,4

4,1

7,105,9

4,7

6,6

8,6

9,8

line

polygon

2,2

5 10

5

10

as geometric objects:

points, lines, polygons

as image filescomposed of grid-cells

(pixels)


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Vector data model

} advantage of the vector data format: allowsprecise representation of points, boundaries, andlinear features.

} useful for analysis tasks that require accuratepositioning,

} for defining spatial relationship (ie theconnectivity and adjacency) between coveragefeatures (topology), important for suchpurposes as network analysis (for example tofind an optimal path between two nodes in acomplex transport network)

} main disadvantage of vector data is that theboundaries of the resulting map polygons arediscrete (enclosed by well-defined boundary lines),whereas in reality the map polygons may representcontinuous gradation or gradual change, as in soil

maps.


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Raster data model

}good for representing indistinctboundaries

}thematic information on soil types, soilmoisture, vegetation, ground andtemperatures

} as reconnaissance satellites and aerialsurveys use raster-based scanners, theinformation (ie scanned images) can bedirectly incorporated into GIS

} the higher the grid resolution, the largerthe data file is going to be


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Modelling the real world

1 1 20 50

1 2 24 45

1 3 52 55

2 1 0 45 46

40

...

0 0 0 0 0 0 0 2 0

0 0 0 0 0 1 0 0 0

0 2 0 0 1 0 0 0 0

0 0 0 0 2 0 0 0 0

2 2 2 0 1 ...

x

y


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DATA - Overlays

} Layer: A thematic plane of GIS features containinggeographically and logically related data

} Overlaying involves superimposing two or more map layers toproduce a new map layer.

} Overlaying (superimposing) several maps of a specific areashowing (separately) the Altitude, Temperature distribution, Soiltype, Rainfall, Relative humidity and so on.


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GIS into Public Health

} Geographic Information Science (GIS) has many applications in thefield of Public Health.

} GIS has the ability to combine data from many sources foridentification and mapping of environmental factors associated withdisease factors which make it particularly useful for diseasesurveillance and monitoring.

} It can be a useful tool for analyzing the spread of diseases in bothdeveloped and developing countries as well as a managementstrategy for allocating resources and for understanding high risk

areas of disease.

} Intervention in NTDs (Neglected Tropical Diseases) requires:

} Project planning in program context and population environment

} Situational awareness & decision support of ongoing issues,problems, concerns

} Program and resource management (limited budget, personnel,

time, access)

} Evaluation of program efforts and outcomes

} GIS role in integrating public health practice: Information systemsto

} Enhance Surveillance in space and time

} Improve Intervention practices and policies

} Conduct Evaluation activities and assessment


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GIS concepts are not new!

} London cholera epidemic 1854

Cholera deathCholera death

Water uWater u

SohoSoho

+

Su ers, Judith.Soho -- A History of London's Most Colourful Neighborhood, Bloomsb ry, London, 1989, pp.113-117.


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GIS in Lymphatic Filariasis

} Lymphatic Filariasis represents a major, vector-borne,public-health problem in India.

} The existence of a national programme for Filariasiscontrol [designated the National Filaria Control

Programme (NFCP)] since 1955 attests to therecognition by health planners of the public-healthimportance of the disease in India.

} Mapping the geographical distribution of filarial infectionwithin countries allows the visualization, identification

and prioritization of target areas for intervention.

} Secondly, such maps are prerequisite for more preciseassessments of the endemic populations at risk,enabling more accurate estimations of the overall drugrequirements for national programs for control.


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FILARIA ENDEMIC DISTRICTS

Trend Of Average MF rate

Year 2004 2008

National

Average

1.24 0.63


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DAYTIME SURVEY

Front Door survey datacollection


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Name of the individual:

Age: Sex: Marital status:

Infection status: MF/ LF/ Symptomatic MF/ Asymptomatic LF

District: Block: Village: Pincode:

Immunological

Testing Results:

Antigens tested: Antibodies tested: Other tests:

Blood film test results Blood collected at: ___ PM/AM Blood smear result:

Positive MF / Negative

Locality Hygiene information Is there any water stagnant present nearby:

Yes/ No/NA

Is there mosquitoes spread observed:

Heavily/ Moderately/ No /NA

Is there water drainage is proper in the

locality:

Yes/ No /NA

Personal Hygiene information Is there clean lavatories and bathrooms with

proper drainage:

Yes/ No / NA

Is there mosquito nets surround the house:

Yes/ No /NA

Is there mosquito propellant used

regularly:

Yes/ No / NA

LF Relevant Symptoms Hydrocele / Breastocele Lymphatic ducts Fever/ nausea/ others

Family and neighbors infection status Any of the family members with LF history:

Yes / No/NA

Any of the neighbors with LF history:

Yes / No/ NA

If Yes Information regarding the

infection:

History of any other vector borne

diseases like malaria

Malarial infection status of the subject, family

and neighbors

Yes/ No / NA

Any other parasitic and vector born disease among

the family and neighbors:

Yes/ No /NA


infection:

History of any other chronic infections

among the individual family and

neighbors

Is there any chronic viral/ bacterial infections in

the family:

Yes / No / NA

Is there any chronic viral/ bacterial infections in the

Neighbors:

Yes / No / NA


infection:

History of Smoking and Alcoholic

behavior

Does the subject have Smoking habit:

Heavily/ Moderately/ No / NA

Does the subject have Alcoholism:

Heavily/ Moderately/ No

History of Non/ infectious diseases of

the subject

Does the subject suffer from any non-infectious

diseases:

Yes / No/ NA

Does the subject suffer from any Auto-immune

disorders:

Yes / No / NA

If Yes Information regarding the disease:

Treatment procedures underway Is DEC treatment is implemented to the subject:

Yes/ No/ NA

Is Mass Drug Administration is implemented to the

subject:

Yes/ No/ NA

Any other treatment procedures the

subject undergoing for LF:

Previous survey detai ls: Is the subject surveyed previously for LF:

Yes/ No/ NA

Is the subject given blood sample for LF s creening

before:

Yes/ No/ NA

Other Filarial infection status Loasis:

Yes/ No/ NA

Onchocerciasis:

Yes/ No/ NA

NFCP implementation details Is there National Filariasis control programme is

implemented:

Yes/ No/ NA

If yes information regarding the NCFP

implementations:

Questionnaire for LF sampling field visit


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NIGHTTIME SPECIMEN COLLECTION

Specimen collection andrecording

NIGHT is the critical time


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Field Visit -

Sampling &

Questionnaire

Field Office

System Data

Storage

Central Server RepositoryResearchLabanalysis

7GP11_LymphFil05

System Components & Flow Chart of

advancements in GIS

Publish


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GOALS OF GIS IN LF

Goals relevant to Surveillance andAssessment

y Where are key locations of infected persons inpopulation

y Where are key locations of infected mosquitopopulations

Goals relevant to Program Interventionand Management

y Do we need additional vector control (spraying)of additional ponds?

y Do we need further MDA intervention planningwithin 200 yard radius?

Goals relevant to Program Evaluation andAssessment


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GIS Case study (1073 Subjects)} GIS mapping ofLF in endemic areas in Gampaha District,

Srilanka; based on the epidemiological and entomological

screening.} Objective: Development of a site directed map for LF

dispersed areas in Gampaha district, Srilanka as a guide totarget control activities.

} Methodology:

}Pre-identified 9 sites in Gampaha district for

LF screening

} Epidemiological night-blood screening by blood smear test

} Entomological pool screening of vectors by conventional dissectionmethod for L1, L2 or L3 staging, PCR-ELISA using NV1&2 primersspecific for SspIrepeats.

} Results:

} Epidemiological investigation: only 2 out of 9 sites were having mf +vesubjects, among those 2 sites, Peliyagoda persists 3.4% of mf+vecases and the Hekiththa shows only 0.5% mf+ve subjects.

} Entomological investigation: 0-45 mosquitoes/household werecollected; Conventional microscopic investigation revealed -44.5% rateof infestation, only 8.54% were positive mosquitoes and L1 densitywas 1 per +ve mosquito.

Wijegunawardana et al., Molecular Medicine Unit,Faculty of Medicine, University of Kelaniya,Ragama,Sri Lanka


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Objective of The present study

} Improvement of the analytical strategies in GIS toolscurrently used in lymphatic filariasis

} Characterization of PCR-based, alt-2 intron-3 tandemrepeats (IR3) variation analysis to differentiallydiagnose the major lymphatic filarial species B.malayiand W. bancroftiamong patients.


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Methodology

} Development of the GIS by improving the analytical strategiesto improvise the LF-GIS.

} Consolidation of the old GIS data in LF among India.

} Addition of various new data in the current GIS survey ofthe LF samples presently collected

} Subjecting the new data with the filarial infection details inmultiple analysis databases to upgrade the present LF-GIS.

} PCR analysis of IR3 variation among patients

} Collection of clinical samples from endemic areas duringGIS studies and isolation of mf genomic DNA.

} PCR analysis of IR3 variation among the mf DNA samples to

confirm and differentiate brugian filariasis from bancroftianfilariasis.


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Outcome of the Present study

} The improvement of GIS could potentially helps inmonitoring the LF endemic regions and the variousfactors attribute the LF spread out also it helps todevelop new LF detection, monitoring anderadication strategies. The development of sensitivePCR based and Immunological based differentialdetection methods could possibly provide a sensitiveLF diagnostic protocol and reduces the error rates.


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Documents

Geographical Information System in Lymphatic Filariasis