Livestock, Pathogens, Vectors, and Their Environment: A Causal Inference-Based Approach to Estimating the Pathway-Specific Effect of Livestock on Human African Trypanosomiasis Risk

Details

• Personal Author:
  Ismail Taban A ; Kato A ; Lemerani M ; Mayer J ; Meisner J ; Mwamba Miaka E ; Pigott DM ; Rabinowitz PM ; Rowhani-Rahbar A ; Wakefield J
• Description:
  Livestock are important reservoirs for many zoonotic diseases, however the effects of livestock on human and environmental health extend well beyond direct disease transmission. In this retrospective ecological cohort study we use pre-existing data and the parametric g-formula, which imputes potential outcomes to quantify mediation, to estimate three hypothesized mechanisms by which livestock can influence human African trypanosomiasis (HAT) risk: the reservoir effect, where infected cattle and pigs are a source of infection to humans; the zooprophylactic effect, where preference for livestock hosts exhibited by the tsetse fly vector of HAT means that their presence protects humans from infection; and the environmental change effect, where livestock keeping activities modify the environment in such a way that habitat suitability for tsetse flies, and in turn human infection risk, is reduced. We conducted this study in four high burden countries: at the point level in Uganda, Malawi, and Democratic Republic of Congo (DRC), and at the county level in South Sudan. Our results indicate cattle and pigs play a reservoir role for the rhodesiense form (rHAT) in Uganda (rate ratio (RR) 1.68, 95% CI 0.84, 2.82 for cattle; RR 2.16, 95% CI 1.18, 3.05 for pigs), however zooprophylaxis outweighs this effect for rHAT in Malawi (RR 0.85, 95% CI 0.68, 1.00 for cattle, RR 0.38, 95% CI 0.21, 0.69 for pigs). For the gambiense form (gHAT) we found evidence that pigs may be a competent reservoir (RR 1.15, 95% CI 0.92, 1.72 in Uganda; RR 1.25, 95% CI 1.11, 1.42 in DRC). Statistical significance was reached for rHAT in Malawi (pigs and cattle) and Uganda (pigs only) and for gHAT in DRC (pigs and cattle). We did not find compelling evidence of an environmental change effect (all effect sizes close to 1). [Description provided by NIOSH]
• Subjects:
  Cohort Studies Livestock Occupational Health Safety
• Keywords:
  Animal-related Diseases Cohort Studies Disease Vectors Ecological Systems Parasitic Diseases Zoonoses
• ISSN:
  2767-3375
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  OSHA Region 10 ; Washington
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  3
• Issue:
  11
• NIOSHTIC Number:
  nn:20069709
• Citation:
  PLOS Glob Public Health 2023 Nov; 3(11):e0002543
• Contact Point Address:
  Julianne Meisner, Center for One Health Research, University of Washington, Seattle, Washington, United States of America
• Email:
  meisnerj@uw.edu
• Federal Fiscal Year:
  2024
• Performing Organization:
  University of Washington
• Peer Reviewed:
  True
• Start Date:
  20050701
• Source Full Name:
  PLOS Global Public Health
• End Date:
  20250630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:0850d77b1f46c1c1801adbd5525cc4a01d2affa2eeb0590c6d3302dccc3cda12c2276a13c7390ce31e8a5f3f884ed98aed659b848d2f051604ca9f814b72fdea
• Download URL:
  https://stacks.cdc.gov/view/cdc/208082/cdc_208082_DS1.pdf
• File Type:
  [PDF - 1.32 MB ]