Estimation of the burden of leptospirosis in New Zealand

Juan M Sanhueza; Michael G Baker; Jackie Benschop; Julie M Collins-Emerson; Peter R Wilson; Cord Heuer

doi:10.1111/zph.12668

Estimation of the burden of leptospirosis in New Zealand

Zoonoses Public Health. 2020 Mar;67(2):167-176. doi: 10.1111/zph.12668. Epub 2019 Dec 4.

Authors

Juan M Sanhueza¹, Michael G Baker², Jackie Benschop³, Julie M Collins-Emerson³, Peter R Wilson⁴, Cord Heuer⁴

Affiliations

¹ Veterinary Population Medicine Department, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN, USA.
² Department of Public Health, University of Otago, Wellington, New Zealand.
³ Molecular Epidemiology and Public Health Laboratory, School of Veterinary Science, Massey University, Palmerston North, New Zealand.
⁴ EpiCentre, School of Veterinary Science, Massey University, Palmerston North, New Zealand.

PMID: 31799801
DOI: 10.1111/zph.12668

Abstract

Background: Human leptospirosis mainly affects people in close occupational contact with domestic livestock and their products in New Zealand. The disease has an unquantified impact on both human health and animal production in the country. This study aimed to estimate the burden of leptospirosis in terms of disability-adjusted life years (DALYs) and cost associated with loss due to absence from work, treatment of disease, animal production loss and cost of vaccination.

Methods: Previously published studies of abattoir workers farmers, and veterinarians, reporting annual risks of influenza-like illness attributable to Leptospira infection, were used to estimate the expected number of cases in a year. The cost of lost animal production was based on results of observational studies in beef cattle, sheep and deer conducted in New Zealand.

Results: Expected median annual number of severe and mild cases of human leptospirosis was 2,025 (95% probability interval [95% PI] 1,138-3,422). Median annual DALYs were 0.42 (95% PI: 0.06-2.40) per 100,000 people for the entire population, and 15.82 (95% PI: 2.09-90.80) per 100,000 people working in at-risk occupations (i.e. abattoir workers, farmers and veterinarians). Human infection resulted in a median cost of 4.42 (95% PI: 2.04-8.62) million US dollars (USD) due to absence from work and disease treatment. Median production loss cost in beef cattle, sheep and deer was USD 7.92 (95% PI: 3.75-15.48) million, while median vaccination cost in cattle, (including dairy), sheep and deer was USD 6.15 (95% PI: 5.30-7.03) million. Total annual cost of leptospirosis plus vaccination was USD 18.80 (95% PI: 13.47-27.15) million, equivalent to USD 440,000 (95% PI: 320,000-640,000) per 100,000 people.

Conclusion: This study provides an estimate of the disease burden and cost of leptospirosis in New Zealand that could support occupational health authorities and livestock industries in assessing interventions for this disease.

Keywords: DALYs; burden; cost; human; leptospirosis; livestock.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Bacterial Vaccines / administration & dosage
Bacterial Vaccines / economics
Computer Simulation
Cost of Illness*
Humans
Leptospirosis / economics*
Leptospirosis / epidemiology*
Leptospirosis / prevention & control
Leptospirosis / veterinary
Livestock
Models, Economic
New Zealand / epidemiology
Zoonoses

Substances

Bacterial Vaccines