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Cause:
Protozoan Giardia lamblia,
also known as G. intestinalis or G. duodenalis.
Illness and treatment:
Infection may be
asymptomatic or may cause diarrhea, abdominal pain, nausea,
fatigue, and weight loss. Illness may be self-limited or be
prolonged with persistent pale and greasy stools due to fat
malabsorption. Anti-protozoal drugs are available.
Sources:
Humans and both wild and
domestic animals are reservoirs. Exposures include untreated
surface water, shallow well water, recreational water, or
less commonly food contaminated by feces. Person-to-person
transmission occurs, such as in child care facilities, or
through oral-anal sexual contact.
Additional risks:
Children under 5 years
of age are infected more frequently than adults.
Concentrations of chlorine used in routine water treatment
do not kill Giardia cysts, especially if the water is
cold. Giardiasis is one of the most common waterborne
diseases in the country.
Prevention:
Wash hands thoroughly after
contact with animals, particularly animals with diarrhea.
Avoid swallowing water during water recreation. Do not drink
untreated surface water. Boil untreated drinking water for
one minute or use other appropriate water treatment.
Recent Washington trends:
Reported cases
have been declining somewhat over the past decade. Incidence
is highest in the summer and fall months. Most frequently
reported exposures include recreational water and
international travel. Outbreaks are uncommon.
2008:
486 cases were reported (7.4
cases/100,000 population). The infection was diagnosed more
than twice as commonly in children 1 to 4 years of age than
people in any other age group.
Purpose of Reporting and
Surveillance
- To identify sources of
major public health concern (e.g., a public water supply)
and to stop transmission from such a source and prevent
future recurrences.
- To identify whether the
case may be a source of infection for other persons (e.g., a
diapered child or child care attendee), and, if so, to
prevent further transmission.
Legal Reporting Requirements
-
Healthcare
providers: notifiable to local health jurisdiction
within 3 work days
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Hospitals:
notifiable to local health jurisdiction within 3 work
days
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Laboratories:
no requirements for reporting
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Local health
jurisdictions: notifiable to Washington State Department
of Health (DOH) Communicable Disease Epidemiology
Section (CDES) within 7 days of case investigation
completion or summary information required within 21
days
Last
update
November 2009 |
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