Sero-Prevalence and Risk Factors for Leptospirosis in Abattoir Workers in New Zealand
Abstract
:1. Introduction
2. Experimental Section
2.1. Study Design, Data Collection and Serological Testing
2.2. Case Definitions
2.3. Sample Size and Power Calculation
2.4. Data Analysis
2.4.1. Categories of Work Position and Personal Protective Equipment
Species | Variable | Category | Adjusted OR | 95% CI | p-value |
---|---|---|---|---|---|
Sheep | Work position | Boning, chillers, office | Ref. | ||
Offal, pet food | 6.5 | 1.4–29.8 | 0.017 | ||
Gut removal, pulling kidneys | 8.2 | 2.1–32.7 | 0.003 | ||
Yards, stunning, pelting | 10.4 | 2.8–38.8 | <0.001 | ||
Gender | Female | Ref. | |||
Male | 3.1 | 0.8–11.7 | 0.089* | ||
Years worked at meat plant | (Continuous) | 1.1 | 1.0–1.1 | 0.011 | |
Meat plant | Sheep 1 | Ref. | |||
Sheep 2 | 4.5 | 1.2–16.3 | 0.022 | ||
Sheep 3 | 6.3 | 1.8–22.4 | 0.004 | ||
Sheep 4 | 2.1 | 0.7–6.3 | 0.201* | ||
Deer | Work position | Boning, Chillers, Office | Ref. | ||
Offal, pet food, gut removal, pulling kidneys, yards, stunning, pelting | 12.7 | 1.3–120.6 | 0.027 | ||
Wear facemask, or safety glasses | Never or sometimes | Ref. | |||
Often or always | 4.3 | 0.8–22.8 | 0.093* | ||
Beef | Work position | Boning, chillers, office | Ref | ||
Maintenance | 2.0 | 0.3–23.4 | 0.59* | ||
Offal, pet food | 3.1 | 0.5–20.6 | 0.25* | ||
Yards, stunning, pelting, gut, kidney removal & meat inspection | 2.2 | 0.5–10.8 | 0.32* | ||
Age (years) | Continuous | 1.1 | 1.0–1.2 | 0.02 |
2.4.2. Multivariable Analysis
3. Results
3.1. Participants, Slaughter Plants and Study Population
Abattoir | Total Number of Workers | Study Recruits (%) | Species Processed | Number of Animals Processed per Year | Regions of Animal Origin |
---|---|---|---|---|---|
Sheep 1 | 889 | 12 | Lamb, mutton, bobby calves | 1,797,809 | Hawke’s Bay, Waikato, Wairarapa, Bay of Plenty, Northland |
Sheep 2 | 378 | 26 | Lamb, mutton, goats | 600,469 | Gisborne, Hawke’s Bay, Waikato, Bay of Plenty |
Sheep 3 | 300 | 11 | Lamb | 780,000 | Central Hawke’s Bay, East Coast, Wairarapa, Manawatu |
Sheep 4 | 180 | 51 | Lamb, mutton, bobby calves, goats | 488,546 | Wanganui, Manawatu, Taranaki, other |
Deer 1 | 41 | 51 | Venison | 24,222 | Canterbury |
Deer 2 | 59 | 61 | Farmed & feral a venison | 41,055 | South Waitaki River to Rakaia, North Canterbury |
Beef 1 | 486 | 15 | Beef cattle, dairy cows | 93,837 | East Coast, West Coast, Waikato, Bay of Plenty, Northland |
Beef 2 | 328 | 34 | Beef cattle | 159,347 | Taranaki, Waikato, Manawatu, Hawke’s Bay |
3.2. Sero-prevalence and Antibody Titres
Abattoir | Participants | Prevalence (%) | |||||
---|---|---|---|---|---|---|---|
Pom (%) | 95% CI (%) | Har (%) | 95% CI (%) | Either (%) | 95% CI (%) | ||
Sheep1 | 104 | 5 | 2–11 | 10 | 5–17 | 12 | 7–19 |
Sheep2 | 97 | 8 | 4–16 | 4 | 2–10 | 11 | 6–19 |
Sheep3 | 32 | 16 | 7–32 | 28 | 15–46 | 31 | 18–49 |
Sheep4 | 92 | 5 | 2–12 | 7 | 3–14 | 10 | 5–18 |
Deer1 | 21 | 5 | 1–27 | 19 | 7–41 | 19 | 7–41 |
Deer2 | 36 | 6 | 11–20 | 11 | 4–26 | 17 | 8–32 |
Beef1 | 73 | 3 | 1–10 | 4 | 1–12 | 5 | 2–14 |
Beef2 | 112 | 1 | 0–6 | 5 | 2–11 | 5 | 2–11 |
Total | 567 | 5 | 3–7 | 8 | 6–10 | 11 | 8–14 |
3.3. Disease
3.4. The Use of Personal Protective Equipment
3.5. Risk Factors for Sero-prevalence in Sheep Plants
3.6. Risk Factors for Sero-prevalence in Deer Abattoirs
3.7. Risk Factors for Sero-prevalence in Beef Abattoirs
4. Discussion and Conclusions
4.1. Sero-prevalence
4.2. Probable Leptospirosis
4.3. Risk Factors for Sero-positivity
Supplementary Files
Acknowledgments
Author Contributions
Conflicts of Interest
References
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Dreyfus, A.; Benschop, J.; Collins-Emerson, J.; Wilson, P.; Baker, M.G.; Heuer, C. Sero-Prevalence and Risk Factors for Leptospirosis in Abattoir Workers in New Zealand. Int. J. Environ. Res. Public Health 2014, 11, 1756-1775. https://doi.org/10.3390/ijerph110201756
Dreyfus A, Benschop J, Collins-Emerson J, Wilson P, Baker MG, Heuer C. Sero-Prevalence and Risk Factors for Leptospirosis in Abattoir Workers in New Zealand. International Journal of Environmental Research and Public Health. 2014; 11(2):1756-1775. https://doi.org/10.3390/ijerph110201756
Chicago/Turabian StyleDreyfus, Anou, Jackie Benschop, Julie Collins-Emerson, Peter Wilson, Michael G. Baker, and Cord Heuer. 2014. "Sero-Prevalence and Risk Factors for Leptospirosis in Abattoir Workers in New Zealand" International Journal of Environmental Research and Public Health 11, no. 2: 1756-1775. https://doi.org/10.3390/ijerph110201756