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Giardiasis

Scientific name
Giardia duodenalis (G. lamblia, G. intestinalis)
Organism type
Parasite
Symptoms
Diarrhea, gas, greasy stools, stomach cramps, upset stomach, nausea.
Incubation period
Average 1-3 weeks
Transmission
Contaminated water (including recreational water), contaminated food, person-to-person.

An intestinal illness caused by the microscopic parasite Giardia, one of the most common causes of waterborne disease.

Limited data currently published for this disease

Public Health Trace does not yet have any commonly associated foods for Giardiasis. Everything below reflects only what has actually been published.

Provisional data. Reported case counts for the most recent weeks are provisional and subject to revision by CDC as more reports come in.

Reported case trend

There isn't enough reported data in this period to summarize a trend.

Reported cases by state

No states reported cases in this dataset for the selected period.

Case-level state data unavailable

CDC's weekly surveillance reports aren't currently linked to individual states in Public Health Trace's data (a known data-pipeline gap, not a lack of real activity). The map below, built from individual reported outbreak investigations instead, is a real, working substitute for state-level context on this disease.

Historical outbreaks by state

A map shading each state by the number of historical outbreak investigations linked to this disease.

Shading reflects state-level totals only, as published by the source. It does not imply county-level or point-level precision.

Show full state data table
Historical outbreaks by state
State Outbreak count
Pennsylvania 22
Minnesota 17
Wisconsin 7
Idaho 5
Utah 5
Ohio 4
Colorado 4
South Carolina 4
Texas 4
Louisiana 3
Washington 3
Georgia 2
West Virginia 2
Virginia 2
Nevada 2
Florida 1
South Dakota 1
Kentucky 1
Arizona 1
Illinois 1
Montana 1
Massachusetts 1
Alabama 1
Puerto Rico 1
Hawaii 1
Tennessee 1
Rhode Island 1
Maryland 1
Alaska 1

Active investigations aren't included here -- FDA and CDC elevated-activity sources report at a national level, not by individual state. See current alerts for those.

Historical outbreaks

Past outbreak investigations linked to Giardiasis, newest first.

View all 100 historical outbreaks

Outbreak United StatesHistorical record

Astrovirus;Rotavirus;Giardia unknown;Sapovirus unknown;Norovirus unknown;Clostridium difficile

State
Montana
Cases
8
Start date
May 1, 2022
Last updated

Source: CDC NORS Archive

View Investigation

Outbreak United StatesHistorical record

Escherichia coli, Enteroaggregative;Giardia unknown;Norovirus unknown

State
Massachusetts
Cases
21
Start date
October 1, 2021
Last updated

Source: CDC NORS Archive

View Investigation

Outbreak United StatesHistorical record

Giardia duodenalis;Escherichia coli, Enteropathogenic;Cryptosporidium parvum

State
Wisconsin
Cases
5
Start date
March 1, 2019
Last updated

Source: CDC NORS Archive

View Investigation

Outbreak United StatesHistorical record

Rotavirus;Giardia unknown;Sapovirus unknown

State
West Virginia
Cases
7
Start date
February 1, 2019
Last updated

Source: CDC NORS Archive

View Investigation

Outbreak United StatesHistorical record

Salmonella enterica;Cryptosporidium unknown;Giardia unknown

State
Ohio
Cases
3
Start date
November 1, 2018
Last updated

Source: CDC NORS Archive

View Investigation

Outbreak United StatesHistorical record

Giardia unknown;Norovirus unknown;Escherichia coli, Enteropathogenic

State
South Carolina
Cases
12
Start date
October 1, 2018
Last updated

Source: CDC NORS Archive

View Investigation

Outbreak United StatesHistorical record

Escherichia coli, Enteroaggregative;Giardia unknown;Escherichia coli, Enteropathogenic;Adenovirus unknown

State
Minnesota
Cases
4
Start date
September 1, 2018
Last updated

Source: CDC NORS Archive

View Investigation

Outbreak United StatesHistorical record

Cryptosporidium unknown;Giardia unknown;Norovirus unknown;Escherichia coli, Enteropathogenic;Escherichia coli, Enteropathogenic;Escherichia coli, Enteroaggregative;Escherichia coli, Enteroinvasive;Norovirus Genogroup I;Norovirus Genogroup II;Norovirus Genogroup IX

State
Tennessee
Cases
693
Start date
June 1, 2018
Last updated

Source: CDC NORS Archive

View Investigation

Outbreak United StatesHistorical record

Cryptosporidium unknown;Giardia unknown;Escherichia coli, Shiga toxin-producing;Escherichia coli, Other

State
Colorado
Cases
101
Start date
June 1, 2018
Last updated

Source: CDC NORS Archive

View Investigation

Outbreak United StatesHistorical record

Cryptosporidium unknown;Giardia unknown;Cryptosporidium parvum

State
Rhode Island
Cases
54
Start date
March 1, 2018
Last updated

Source: CDC NORS Archive

View Investigation

Search historical outbreaks for Giardiasis

Freshness unavailable for one or more included sources

This page describes reported surveillance data, not a diagnosis or individualized medical or treatment advice. If you believe you are experiencing symptoms of a foodborne illness, contact a healthcare provider. Read the full medical disclaimer.