Outbreak of giardiasis associated with a community drinking-water source.
Giardiasis is a common waterborne gastrointestinal illness. In 2007, a community giardiasis outbreak occurred in New Hampshire, USA. We conducted a cohort study to identify risk factors for giardiasis, and stool and environmental samples were analysed. Consuming tap water was significantly associated with illness (risk ratio 4.7, 95% confidence interval 1.5-14.4). Drinking-water samples were coliform-contaminated and a suspect Giardia cyst was identified in a home water filter. One well was coliform-contaminated, and testing indicated that it was potentially under the influence of surface water. The well was located 12.5 m from a Giardia-contaminated brook, although the genotype differed from clinical specimens. Local water regulations require well placement at least 15 m from surface water. This outbreak, which caused illness in 31 persons, represents the largest community drinking-water-associated giardiasis outbreak in the USA in 10 years. Adherence to well placement regulations might have prevented this outbreak.
Daly
E R
ER
New Hampshire Department of Health and Human Services, Concord, NH 03301-6504, USA. erdaly@dhhs.state.nh.us
Roy
S J
SJ
Blaney
D D
DD
Manning
J S
JS
Hill
V R
VR
Xiao
L
L
Stull
J W
JW
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D002648:Child; D002675:Child, Preschool; D016054:DNA, Protozoan / Q000737:chemistry / Q000235:genetics; D004196:Disease Outbreaks; D004755:Enterobacteriaceae / Q000302:isolation & purification; D005260:Female; D005838:Genotype; D005872:Giardia / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D005873:Giardiasis / Q000453:epidemiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009513:New Hampshire / Q000453:epidemiology; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D014867:Water / Q000469:parasitology*; D055815:Young Adult
D016054:DNA, Protozoan; D014867:Water