Leptospirosis in the Tropics: When Prevention Doesn't Easily Sell as a Ton of Cure

Abstract:     
Problem statement: Human leptospirosis - the most widespread zoonotic disease - thrives well in tropical and subtropical climates. It is seldom addressed ex ante or prior to an outbreak, or expected outbreak, by governments of high-risk countries. Whether common, post-exposure treatment with antimicrobial drugs is more cost-efficient than reducing animal reservoir populations was the overarching question that guided this study. A related question in this study was how to establish comparability of price or cost estimates for these two treatment methods.

Approach: Annualized price samples of government-approved, antimicrobial therapies, particularly antibiotics, and appropriate anti-rat/anti-rodent chemical agents (rodenticides) were gathered from three leptospirosisendemic countries: Brazil, the Philippines and Sri Lanka. Certain price data were adjusted for present value based on a linear cost accounting function. Two-tailed hypothesis-testing (α = 0.05) was performed to determine any statistically significant differences in pricing antimicrobial therapies and rodenticides in each country under investigation.

Results: Shared environmental issues and socio-demographic characteristics of infected populations appear to support the need for ex ante containment of rat/rodent reservoir populations in high-risk tropical and subtropical countries. In each t-tested country, we found that tcrit>tobs>-tcrit. Therefore, the null hypothesis, μantimicrobial = μrodenticides; μantimicrobial - µrodenticides = 0, could not be rejected in favor of the alternative hypothesis, μantimicrobial ≠ μrodenticides; μantimicrobial - μrodenticides ≠ 0.

Conclusion: Applications of Price Estimation (PE) methods in financial economics, such as present value, help optimize health decisions concerning zoonotic diseases. Leptospira transmission in Brazil, the Philippines and Sri Lanka illuminate the need for broad and cohesive policies that take into account zoocentric measures. These may be critical in high-risk, tropical and subtropical countries that periodically experience flooding, standing water and increased rainfall.

Keywords: Antibiotic Prophylaxis, Antimicrobial Drugs, Demonstration Effects, Ex Ante, Exposure, Leptospirosis, Present Value, Price Estimation, Rodenticides, Zoocentric, Zoonosis

JEL Classification: I12, 118, I19

Accepted Paper Series