Giardiasis is caused by the Giardia intestinalis parasite. It is a common intestinal infection spread through ingestion of cysts from contaminated food, water, or surfaces. Symptoms include diarrhea, abdominal cramps, nausea and vomiting. Diagnosis is made through examination of stool samples microscopically or through antigen testing. Treatment involves antibiotics like metronidazole or tinidazole. Prevention focuses on proper hygiene and sanitation practices like handwashing. Giardiasis is found worldwide but is more common in areas with poor sanitation.

1. GARDIASIS
PRESENTED TO :
DR SHAKIRA SADIQ GILL
PRESENTED BY :
Abdul Wajid
2012-mphil- 2180
department epidemiology and public health

2. Contents
 Introduction and etiology
 Epidemiology
 transmission
 Who is at Risk?
 Signs & symptoms
 Incubation period
 Life cycle
 Diagnosis
 Differential diagnosis
 Treatment
 Prevention

3. Introduction and etiology
 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 motile ,vegetative tropozpite is 10-20µm long and 8-15µm wide.
 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, one of the most common causes of
waterborne disease (drinking and recreational) in humans in the United
States
 Very contagious

5. Epidemiology
 Giardiasis is a global disease.
 It infects nearly 2% of adults and 6% to 8% of children in developed
countries worldwide.
 Nearly 33% of people in developing countries have had giardiasis.
 In the United States, Giardia infection is the most common
intestinal parasitic disease affecting humans
 G. intestinalis has high prevalence rates particularly among young
children in third world countries.

6. Continue…..
 In tropical areas , about 50-80% of people are carriers.
 The variable occurrence in distinct groups of the
population is apparently related to certain nutritional
conditions.
 Latin america is about 200 million, with some 500,000
new infections per year.
 In humans,giardiasis is one of the the most common
intestinal parasitoses in western industrialized countries.

7. Geographical distribution of Giardia
 Worldwide.
 More prevalent in warmer climates and in
young age animals and humans.
 Infection occurs mostly in areas of low
sanitation standards and all the day care
centers.

8. 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

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

10. Giardiasis
Host examples
 Humans
 Cats, dogs
 Cows, lamb
 Beavers, deer
 Manifest in 7-10 days
 Lasts 2- 6 weeks
 Symptoms
 Severe diarrhea
 Abdominal cramps
 Bloating
 Flatulence
 Nausea
 Vomiting
 May lead to
 Weight loss
 Dehydration
Common Chronic
vs.
• More severe condition
• Lasts 2 months - years
• Symptoms
– Increased gas
– Dehydration
– Burping
– Loose stools
– Slowed growth

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

12. Transmission
 Giardiasis is passed via the face- oral route.
 Primary routes are personal contact and contaminated water and
food.
 people who have contact with individuals already infected.
 It is a particular danger to people hiking or backpacking in
wilderness areas worldwide, especially if they have no immediate
access to medical supplies.

13. Transmission and Life cycle of
Giardia

14. Life Cycle (Pectoral representation)

15. Life cycle
 Cysts are resistant forms and are responsible for transmission
of giardiasis. Both cysts and trophozoites can be found in the
feaces (diagnostic stages) .
 The cysts are hardy and can survive several months in cold
water. Infection occurs by the ingestion of cysts
in contaminated water, food, or by the fecal-oral route
(hands or fomites) .
 In the small intestine, excystation releases trophozoites
(each cyst produces two trophozoites) .

16. o Trophozoites multiply by longitudinal binary fission, remaining
in the lumen of the proximal small bowel where they can be
free or attached to the mucosa by a ventral sucking disk
o Encystation occurs as the parasites transit toward the colon.
The cyst is the stage found most commonly in no diarrheal
feces .
o Because the cysts are infectious when passed in the stool or
shortly afterward, person-to-person transmission is possible.
While animals are infected with Giardia, their importance as a
reservoir is unclear.

17. Zoonotic Aspects of Giardia
 Giardia lamblia which parasitize humans belong to either of
two genotypes, A or B,
 These two genotypes also were found in cysts from fecal
samples of animal origin such as dogs, cats, some farm
animals and wild animals.
 In addition, trophozoites recovered from cysts obtained
from environmental samples belonged to these two
genotypes as well, suggesting that the G. lamblia genotypes
A and B are widespread and possibly zoonotic.

18. Diagnosis
 Fecal immunoassays that are more sensitive and specific should be
used.
 Rapid immune-chromatographic cartridge assays also are available
but should not take the place of routine ova and parasite
examination.
 PCR (e.g.,polymerase chain reaction) can be used to identify the
subtypes of Giardia.

19. Continue….
• Giardia should be identified 50 to 70% of the time after
one stool, and 90% identification after three stools
• Biopsy tissue/duodenal aspirate stained by trichrome
or Giemsa stain.
• Enzyme immunoassay and fluorescent-anitbody
monoclonal antigen detection systems

20. C
 Giardia is also suspected to be zoonotic communicable
between humans and other animals.
 Major reservoir hosts include
 Dogs
 Cats
 horses
 humans
 cattle and birds

21. DIFFERENTIAL DIAGNOSIS
Giardiasis must be differentiated from:
 Bacterial diarrhoea,
 Amoebic diarrhoea,
 Salmonellosis
 Viral gastroenteritis.

22. Giardia – Zoonotic transmission?

23. Treatment
Several prescription drugs are available
metronidazole
Tinidazole
Nitazoxanide.
Alternatives to these medications include
paromomycin, quinacrine, and furazolidone.
Young children & pregnant women may be more
susceptible
Drink plenty of fluids while ill

24. Prevention
Practice good hygiene
Wash hands properly 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

25. Continued…
 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

27. Refrences
 http://www.cdc.gov/parasites/giardia/gen_info/index.html
 http://ideas.health.vic.gov.au/diseases/Giardiasis-facts.asp
 http://www.stanford.edu/class/humbio103/ParaSites2006/Giardiasis/
epidemiology.htm
 http://www.uptodate.com/contents/epidemiology-clinical-
manifestations-and-diagnosis-of-giardiasis