Zulma Medeiros

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Validation Procedures for Verification of
Elimination of Transmission
Environmental Risk Index
Use for Evaluation, Monitoring, Intervention
and Surveillance of Programs to Eliminate LF

• Zulma Medeiros

Lymphatic Filariasis Elimination in the
Americas 5th Regional Program Review Group (RPRG)
Meeting (San José, Costa Rica, October 2005)
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Environmental Risk Index

• LF connection with environmental sanitation
  conditions is precarious or inadequate
• Population density is high.
• Focal urban distribution collective risk
• How to map these areas?

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Definition of Environmental Risk Index

• The composite index is a measure that combines
  different socioeconomic and environmental
  variables in a synthetic index in order to
  analyze the characteristics of population groups
  living in particular geographic areas (AKERMAN,
  1998).
• To map areas with risk of transmission of LF,
• Identify priority areas.
• Justify use of finances.

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Calculation of Environmental Risk Index

• Important variables
• Water supply
• Sanitation
• Garbage collection
• Family income
• Number of persons per household

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Geographic Area in the Brazilian Demographic
Census
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Geographic Area in the Brazilian Demographic
Census
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Calculation of Environmental Risk Index

• The microareas that exhibited the highest numbers
  of occurrences for each variable considered were
  scored (S) as one (1)
• Whereas those with the lowest number of
  occurrences in each predetermined variable scored
  zero (0).
• i microareas
• j variable
• Sij score of the microareas i in
  relation to the variable j
• OCi occurrence registered for the j within
  the i
• OCmin minimum occurrence of the j, noted
  among several i
• OCm maximum occurrence of the j, noted among
  several i

ESij (OCi OCmin,j)/(OCmáx,j OCmin,j),
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Calculation of Environmental Risk Index

• The risk index for LF in each microarea was
  calculated as the arithmetic average of the
  scores recorded,
• n is the number of variables selected as
  determinants for occurrence of filariasis.

ISRi ?jESij/n ? 100
Interpreted as follows The highest values (in
percentage) indicate the microarea where the risk
of occurrence of infection is greatest.
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Environmental Risk Index Use in Evaluation
Variables Household Questionnaires
Source Bonfim, 2002.
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Environmental Risk Index Use in Evaluation
Variables DemographicCensus
BRAGA et al., 2001
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Environmental Risk Index Use in Monitoring
295 low risk 4 households absent 589 average
risk 295 high risk
1,183 microareas
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Environmental Risk Index Use in Intervention
Source Guimarães, 1995, Secretariat of Municipal
Health of Recife - PE
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Environmental Risk Index Use in Intervention
Source Guimarães, 1995, Secretariat of Municipal
Health of Recife - PE
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Environmental Risk Index Use in Surveillance

• 2,503 microareas
• 627 low risk
• 1249 average risk
• 627 high risk

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Environmental Risk Index Use in Surveillance

• Outlying areas in Metropolitan Area of Recife
  (Northeastern Brazil)
• Moreno, southwest side of Jaboatão dos
  Guararapes
• 02 MF, no autochthonous cases
• 65 clinical manifestations
• Surveillance!
• Cabo de Santo Agostinho, south side of Jaboatão
  dos Guararapes
• 06 MF 1 autochthonous case
• 109 clinical manifestation
• Ponte dos Carvalho
• Native case gtgt clinical manifestation
• This district borders on an endemic area.
• Expansion!

Endemic Areas
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Environmental Risk Index x Other Co-Endemic
Diseases
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Gracias
Obrigada
Thank you