1. Giardiasis

2. Giardiasis
Giardiasis is a diarrheal illness caused by Giardia intestinalis (also known as Giardia lamblia)
The parasite is passed in the stool of an infected person or animal (both cysts & trophozoites)
The parasite is protected by an outer shell that allows it to survive outside the body and in the environment for long periods of time
During the past 2 decades, Giardia has become recognized as one of the most common causes of waterborne disease (drinking and recreational) in humans in the United States
Very contagious

3. Symptoms Symptoms include Some may be asymptomatic diarrhea
loose or watery stool
foul-smelling stool
stomach cramps
upset stomach
weight loss
dehydration
Some may be asymptomatic

4. Incubation Period & Duration
Symptoms generally begin 1-2 weeks after being infected
Duration
Healthy persons, symptoms may last 2-6 weeks

5. How is Giardia spread?
Swallowing recreational water contaminated with Giardia
Eating uncooked food contaminated with Giardia
Possibly found in soil, food, water, or surfaces contaminated with Giardia

6. Who is at risk? Everyone Persons at increased risk include:
child care workers
children who attend day care centers
international travelers
hikers, campers, swimmers
people drinking or accidentally swallowing untreated water

7. Treatment Several prescription drugs are available
Consult with your health care provider
Giardia can infect all people
Young children & pregnant women may be more susceptible
Drink plenty of fluids while ill

8. Prevention Practice good hygiene
Wash hands thoroughly with soap and water
after using the toilet
before handling or eating food
after every diaper change
Protect others by not swimming if experiencing diarrhea

9. Prevention Avoid food that might be contaminated
Wash and/or peel all raw vegetables and fruits before eating
Use uncontaminated water to wash all food that is to be eaten raw
Avoid eating uncooked foods when traveling in countries with minimal water treatment and sanitation systems 
Avoid fecal exposure during sex

10. Prevention Avoid water that might be contaminated
Avoid swallowing recreational water
Avoid drinking untreated water from ponds and streams
Avoid using ice or drinking untreated water when traveling in countries where the water supply might be unsafe
If you are unable to avoid drinking or using water that might be contaminated, then treat the water yourself by:
Heating the water to a rolling boil for at least 1 minute
You can pass Giardia in your stool and contaminate water for several weeks after your symptoms have ended

11. Infectious Diarrhea in Tourists Staying in a Resort Hotel EID January-February 1999, 5 (1) 168-171
British residents ill while staying at a hotel in Greece
6 lab confirmed cases of Giardia
All stayed in the same hotel
School sought advice about excluding a child with diarrhea
6 patients reported that many hotel guest were ill

12. Resort Hotel Outbreak EID January-February 1999, 5 (1) 168-171
British guests arrived at the hotel between May 22 and June
Questionnaire administered by phone
86 booking groups
51 groups – 239 persons interviewed
224 ill while on holiday or within a few days of return
95% diarrhea
Median duration of 13 days
82% stomach cramps
64% vomiting
Median duration of 1 day
35 groups- 138 persons could not be contacted

13. Resort Hotel Outbreak EID January-February 1999, 5 (1) 168-171
224 ill
DEFINITE cases - lab confirmed
70 (31%)
PROBABLE cases – no pathogen identified but had diarrhea lasting 4 or more days
107 (48%)
POSSIBLE cases – no pathogen identified but had diarrhea lasting less than 4 days

14. Table 1: Pathogens identified in DEFINITE cases
No. of definite casesa
(%)
Giardia lamblia 58
(83)
Cryptosporidium parvum 11
(16)
Campylobacter spp. 4
(6)
Salmonella spp. 3
(4)
Entamoeba histolytica 2
(3)
Rotavirus 1
(1)
* Sum exceeds 70 because of co-infections

15. Figure 1. Epidemic curve for diarrhea, by category of case

16. Figure 2. Interval between arrival at hotel and onset of illness (vomiting or diarrhea), by category of case

17. Resort Hotel Outbreak EID January-February 1999, 5 (1) 168-171
Telephone interviews – 54 reports
32 (59%) identified problems with food
Tasted strange
Inadequately cooked or heated
Left out uncovered
27 (50%) identified problems with room water
Sewage smell
Discoloration (around June 4)
7 (13%) identified problems with drinks reconstituted with tap water

18. Resort Hotel Outbreak EID January-February 1999, 5 (1) 168-171
Significantly associated with illness
Consumption of reconstituted orange juice
Consumption of raw vegetables and salads
Reports of problems with water in the hotel room

19. Resort Hotel Outbreak EID January-February 1999, 5 (1) 168-171
2 Principal illnesses due to sewage contamination of the water supply
Viral gastroenteritis outbreak
Giardiasis outbreak

20. Resort Hotel Outbreak EID January-February 1999, 5 (1) 168-171
Point-source
Lab confirmation
129 guests reported that their room water smelled of sewage or was discolored around June 4 (mostly from definite cases)
All avoided tap water
a. Consumption of reconstituted orange juice
Water supply was chlorinated but not filtered at certain points within the hotel