Outbreak of Leptospirosis among Triathlon Participants and Community Residents in Springfield, Illinois, 1998

Abstract

We investigated an outbreak of leptospirosis among athletes and community residents after a triathlon was held in Springfield, Illinois. A telephone survey was conducted to collect clinical information and data on possible risk factors, community surveillance was established, and animal specimens and lake water samples were collected to determine the source of the leptospiral contamination. A total of 834 of 876 triathletes were contacted; 98 (12%) reported being ill. Serum samples obtained from 474 athletes were tested; 52 of these samples (11%) tested positive for leptospirosis. Fourteen (6%) of 248 symptomatic community residents tested positive for leptospirosis. Heavy rains that preceded the triathlon are likely to have increased leptospiral contamination of Lake Springfield. Among athletes, ingestion of 1 or more swallows of lake water was a predominant risk factor for illness. This is the largest outbreak of leptospirosis that has been reported in the United States. Health care providers and occupational and recreational users of bodies of freshwater in the United States should be aware of the risk of contracting leptospirosis, particularly after heavy rains.

HLA-DQ6 and ingestion of contaminated water: possible gene–environment interaction in an outbreak of Leptospirosis

“…Analysis during the outbreak investigation demonstrated that swallowing water was significantly associated with seropositivity among the full race cohort; 16 however, in our study, there was no difference in the proportion reporting a history of swallowing water among laboratory-confirmed cases (18/27, 67%) and controls (30/44, 68%). Table 1 shows the distribution of TNF-a À308 promoter alleles and HLA-DR genotypes.…”

“…Most study subjects were homozygous TNF1 or heterozygous at this site; two individuals were TNF2 homozygous (Datasheets A and D, see Supplementary Information). In all, 13 HLA-DR genotypes 1,3,4,[7][8][9][10][11][12][13][14][15][16] were identified within this cohort; the HLA-DR genotype was unambiguous for all 85 specimens. Bivariate analysis of laboratory-confirmed cases showed no TNF-a polymorphism or HLA-DR genotype significantly associated with case-status (Data-sheets A and D, see Supplementary Information).…”

“…16,17 In a case-control study performed during the outbreak investigation, multivariate analysis identified swallowing one or more mouthfuls of lake-water during the swim portion of the race as the only factor associated with an increased risk of developing clinical or laboratory-confirmed leptospirosis (OR ¼ 2.0, P ¼ 0.02). 16 Although previous studies have associated exposure to leptospire-contaminated water with increased risk of disease, [18][19][20][21][22][23] the 1998 leptospirosis outbreak involved a large cohort of people simultaneously exposed to leptospire-contaminated water. Since these triathletes were of relatively uniform demographic and ethnic background, this outbreak provided a unique opportunity to investigate the association of specific host factors with risk for leptospirosis.…”

Canine Leptospirosis, United States, 2002–2004

“…The MAT is not serovar-specific, but the 7 serovars evaluated in this study belong to different serogroups ( 13 ). Serovar Grippotyphosa, the second most common positive serovar in this study, has also been associated with human leptospirosis outbreaks in the 1990s ( 8 ). …”

“…Case reports have attributed canine infection primarily to serovars Grippotyphosa, Pomona, Bratislava, and Autumnalis ( 4 – 6 ). Although human leptospirosis ceased to be a notifiable disease in 1994, outbreaks are still reported and infecting serovars in humans are antigenically related to the emerging serovars in dogs ( 7 , 8 ). …”