Incidence and underreporting of leptospirosis comparing three diagnostic methods in the endemic region of Urabá, Colombia.

Introduction

Leptospirosis represents a public health problem and is a significant cause of morbidity and mortality in the region of Urabá. However, its notification reveals diagnostic limitations.

Objective

To establish the incidence of leptospirosis in the municipalities of the so-called eje bananero in the Urabá region, to describe the magnitude of underreporting, and to propose guidelines for laboratory diagnosis by the public health network. Materials and methods: Two leptospirosis information sources were used: The national official surveillance system and a cross-sectional study of 479 acute-phase patients from April, 2010, to May, 2012. The diagnosis was made using three different tests: Indirect immunofluorescence, microagglutination test, and blood cultures. The exhaustiveness percentage of each information source was calculatedusing the capture and recapture test.

Results

From the total number of cases, 58% (278/479) were positive for leptospirosis at least by a test and 10.43% (29/278) of cases were positive by all three methods. The inclusion of a native strain in the microagglutination test panel increased the percentage of positivity by 15%. The cumulative incidence rate was 66.5/100,000 inhabitants and the case fatality ratio was 2.15%. The underreporting rates of leptospirosis in the Urabá region were 27.8% in morbidity and 66.6% in mortality.

Conclusion

Under-registration of leptospirosis in the region highlights the necessity to use more than one diagnostic test to identify Leptospira in patients from endemic areas. Underregistration could be a common situation throughout the country.