Sero-prevalence of leptospirosis in workers at a New Zealand slaughterhouse.
OBJECTIVE
To undertake a pilot study to measure the sero-prevalence to Leptospira serovars Hardjo and Pomona in an occupationally exposed group. To evaluate worker age, sex and previous clinical episodes of leptospirosis as risk factors for sero-positivity.


METHODS
A cross-sectional sero-prevalence study was conducted in February and March 2008 at a predominantly sheep slaughterhouse in Hawke's Bay, New Zealand. A single blood sample was collected from 242 meatworkers, comprising 145 men and 97 women. Sera were tested by the Microscopic Agglutination Test (MAT) with a titre cut point of 1:24, using serovars Pomona and Hardjo as antigens. Age, sex, and details of previous clinical episodes of leptospirosis were recorded.


RESULTS
Overall sero-prevalence was 9.5%. Ten (4.1%) workers were positive to serovar Hardjo (titres 1:24-1:192), 13 (5.4%) were positive to serovar Pomona (titres 1:24-1:768), and one worker was positive for both serovars. Sero-prevalence was 13.1% and 4.1% in men and women, respectively. The median age for sero-positive workers was 54 years while that for sero-negative workers was 48 years. Twenty-three workers (9.5%) reported a leptospirosis disease episode 1-35 years previously, and 14 of those were sero-positive in the current study.


CONCLUSIONS
The sero-prevalence observed suggests significant exposure to leptospirosis from sheep in meatworkers in the slaughterhouse studied. This sero-prevalence was similar to that reported in a survey in 1982. Further study is needed to determine the link between sero-prevalence and incidence, whether the prevalence of leptospirosis is similar in other slaughterhouses, and to develop a better understanding of risk factors important for the reduction of exposure of this occupationally acquired disease.
EpiCentre, Institute of Animal, Veterinary and Biomedical Sciences, Massey University, Private Bag 11 222, Palmerston North 4442, New Zealand. j.benschop@massey.ac.nz
Jackie
J
Benschop
Cord
C
Heuer
Patricia
P
Jaros
Julie
J
Collins-Emerson
Anne
A
Midwinter
Peter
P
Wilson
D000003:Abattoirs; D000328:Adult; D017677:Age Distribution; D000818:Animals; D000907:Antibodies, Bacterial / Q000032:analysis; D016001:Confidence Intervals; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D015994:Incidence; D007919:Leptospira / Q000276:immunology*; D007922:Leptospirosis / Q000175:diagnosis / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D009520:New Zealand / Q000453:epidemiology; D016273:Occupational Exposure / Q000009:adverse effects*; D016272:Occupational Health; D010865:Pilot Projects; D011379:Prognosis; D018570:Risk Assessment; D016036:Seroepidemiologic Studies; D012698:Serologic Tests / Q000379:methods; D017678:Sex Distribution
D000907:Antibodies, Bacterial