Analysis of the 1998 outbreak of leptospirosis in Missouri in humans exposed to infected swine.
OBJECTIVE
To determine the extent of leptospirosis in persons exposed to infected swine, confirm the source of disease, define risk factors for infection, and identify means for preventing additional infections during an outbreak in Missouri in 1998.


METHODS
Cross-sectional study.


METHODS
240 people and 1,700 pigs.


METHODS
An epidemiologic investigation was conducted of people exposed to infected pigs from the University of Missouri-Columbia swine herd. The investigation included review of health of the pigs, a cross-sectional study of the people handling the pigs, serologic testing of human and porcine sera, and risk-factor analysis for leptospirosis within the human population.


RESULTS
Serologic testing of samples collected at the time of the investigation indicated that 59% of the pigs had titers to leptospires, denoting exposure. Of the 240 people in the exposed study population, 163 (68%) were interviewed, and of these, 110 (67%) submitted a blood sample. Nine (8%) cases of leptospirosis were confirmed by serologic testing. Risk factors associated with leptospirosis included smoking (odds ratio [OR], 14.4; 95% confidence interval [CI], 1.39 to 137.74) and drinking beverages (OR, 5.1; 95% CI, 1.04 to 24.30) while working with infected pigs. Washing hands after work was protective (OR, 0.2; 95% CI, 0.03 to 0.81).


CONCLUSIONS
Leptospirosis is a risk for swine producers and slaughterhouse workers, and may be prevented through appropriate hygiene, sanitation, and animal husbandry. It is essential to educate people working with animals or animal tissues about measures for reducing the risk of exposure to zoonotic pathogens.
Campagnolo
E R
ER
Centers for Disease Control and Prevention, Epidemic Intelligence Service, Atlanta, GA 30333, USA.
Warwick
M C
MC
Marx
H L
HL
Cowart
R P
RP
Donnell
H D
HD
Bajani
M D
MD
Bragg
S L
SL
Esteban
J E
JE
Alt
D P
DP
Tappero
J W
JW
Bolin
C A
CA
Ashford
D A
DA
D000003:Abattoirs; D000293:Adolescent; D000328:Adult; D000368:Aged; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D003430:Cross-Sectional Studies; D004196:Disease Outbreaks; D004326:Drinking; D005260:Female; D006235:Hand Disinfection; D006801:Humans; D007919:Leptospira / Q000276:immunology; D007922:Leptospirosis / Q000453:epidemiology* / Q000517:prevention & control / Q000635:transmission; D008297:Male; D008875:Middle Aged; D008923:Missouri / Q000453:epidemiology; D009784:Occupational Diseases / Q000453:epidemiology* / Q000517:prevention & control; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects; D013552:Swine; D013553:Swine Diseases / Q000453:epidemiology* / Q000635:transmission; D014481:United States; D016885:United States Department of Agriculture; D014495:Universities; D015047:Zoonoses
D000907:Antibodies, Bacterial