Operative Definitions for Prevention and Control of Leptospirosis in Costa Rica

Abstract

Aim: Leptospirosis is the most frequent zoonotic disease all over the world and requires of an efficient epidemiologic surveillance. The operative definitions of the ""Protocolo para la prevención y control de la Leptospirosis"" (Protocol for the prevention and control of Leptospirosis) in Costa Rica, were evaluated.
Methods: This is a two-step cross-sectional study: a descriptive and an analytic study through a clinical-predictive model using logistic regression. Data was taken from the Centro Nacional de Referencia de Virología y Leptospira at INCIENSA (from January 2001 to June 2003).
Results: From 568 files, 154 were eliminated because they lacked the basic information to classify them according to the protocol. Any of the 414 analyzed files satisfied the criteria for confirmed case; thus, an alternate-expanded definition according to literature (confirmed case= serology ≥ 1:800), was used. Then, there were 52 confirmed cases and 368 suspicious cases. From all variables analyzed independently, only headache (OR= 0.5, IC95% 0.2 -1.1) and male sex (OR 3.01; IC 95% 1.2-8.1) had significant association with the diagnosis of leptospirosis. When grouping clinical and epidemiological variables, the combinations headache + myalgia + epidemiologic background (OR 3.8; IC 95% 1.1-14.9) and systemic symptoms + epidemiologic background (OR 0.01; IC 95%1.2-18.9), had significant association with the diagnosis of leptospirosis, even though they were highly correlated (Kappa>0,8).
Conclusion: With available data and the analysis here carried out it was not possible to validate the case definitions in the protocol, nor create new operative definitions that can be applied in Costa Rica, as well as a definition for probable case.