GARDIASISPRESENTED TO :

DR SHAKIRA SADIQ GILLPRESENTED BY :

Abdul Wajid 2012-mphil- 2180department epidemiology and

public health

Contents

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

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

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.

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.

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.

Who is at risk?EveryonePersons at increased risk include:

child care workerschildren who attend day care centers international travelershikers, campers, swimmerspeople drinking or accidentally swallowing

untreated water

Symptoms Symptoms include

diarrhea loose or watery stool foul-smelling stool stomach cramps upset stomach weight loss dehydration

Some may be asymptomatic

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 Chronicvs.

• More severe condition

• Lasts 2 months - years

• Symptoms– Increased gas– Dehydration– Burping– Loose stools– Slowed growth

Incubation Period & Duration

Incubation period Symptoms generally begin 1-2 weeks after

being infected

Duration Healthy persons, symptoms may last 2-6 weeks

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. 

Transmission and Life cycle of Giardia

Life Cycle (Pectoral representation)

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) .

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.

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.

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.

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

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

DIFFERENTIAL DIAGNOSISGiardiasis must be differentiated from:

Bacterial diarrhoea, Amoebic diarrhoea, Salmonellosis Viral gastroenteritis.

Giardia – Zoonotic transmission?

Treatment

Several prescription drugs are available metronidazoleTinidazoleNitazoxanide.

Alternatives to these medications include paromomycin, quinacrine, and furazolidone.

Young children & pregnant women may be more susceptible Drink plenty of fluids while ill

PreventionPractice good hygiene

Wash hands properly with soap and waterafter using the toilet before handling or eating food after every diaper change

Protect others by not swimming if experiencing diarrhea

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 

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