Leptospirosis in American Samoa--estimating and mapping risk using environmental data

Area of Science:

• Epidemiology
• Environmental Health
• Disease Surveillance

Background:

• Leptospirosis emergence is linked to environmental factors.
• Accurate epidemiological data are limited by under-diagnosis and poor surveillance.
• Predictive risk maps are valuable for identifying high-risk areas, especially where surveillance is weak.

Purpose of the Study:

• Estimate leptospirosis seroprevalence based on environmental factors.
• Produce a predictive disease risk map for American Samoa.
• Assess the accuracy of predictive maps for infection risk.

Main Methods:

• Utilized data on seroprevalence and risk factors from a prior study.
• Collected environmental data including rainfall, altitude, vegetation, soil type, and piggery location.
• Employed multivariable logistic regression to model associations and predict seroprevalence.

Main Results:

• Identified key environmental predictors: lower altitude, agricultural areas, clay soil, and proximity to piggeries.
• Models demonstrated acceptable goodness of fit.
• Correctly classified approximately 84% of leptospirosis cases.

Conclusions:

• Environmental variables effectively identify high-risk areas for leptospirosis.
• Environmental monitoring offers a cost-effective public health surveillance strategy.
• Shifting to environmental health hazard surveillance can enhance leptospirosis control.