Water born disease giardia

1. GIARDIA
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2. INTRODUCTION
◦ Giardia is a microscopic parasite that causes the
diarrheal illness known as Giardiasis.
◦ Giardia (also known as Giardia intestinalis, Giardia
lamblia, or Giardia duodenalis) is found on
surfaces or in soil, food, or water that has been
contaminated with feces from infected humans or
animals.
◦ Giardia is protected by an outer shell that allows it
to survive outside the body for long periods of
time.
◦ Water (drinking water and recreational water) is
the most common mode of transmission.
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3. Giardia duodenalis Trophozoite
◦ Trophozoites are binucleated (looks like a
face). 12-15 µm.
◦ Ventral surface bears adhesive disk to
adhere to surface of intestinal cell.
◦ 8 flagella all arise from kinetosome.
◦ Median bodies occur behind adhesive
disk- function is unknown.
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6. Cyst of Giardia duodenalis
◦ The cyst forms as trophozoites become dehydrated when they
pass through the large intestine.
◦ Morphology:
◦ Ovoid in shape; 8-12 µm long × 7-10 µm wide.
◦ Thin cyst wall.
◦ 4 nuclei present, often concentrated at on end.
◦ Flagella shorten and are retracted within cyst.
◦ Axonemes provide internal support.
◦ Cyst may remain viable in the external environment (usually
water) for many months.
◦ 14 billion cysts can be passed in 1 stool sample.
◦ Moderate infections: 300 million cysts.
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8. Giardia duodenalis
◦ Lives in upper part of small intestine (duodenum,
jejunum, upper ileum).
◦ Here the trophozoites attach to the epithelial cells.
◦ Feeds on mucous that forms in response to irritation.
◦ Also absorbs vitamins.
◦ Interferes with absorption in host especially lipids.
◦ It can also interfere with vitamin/ nutrient absorption.
◦ Vit. A- vision
◦ Vit. D- rickets: Both of these are due to long standing
infection.
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9. Illness and Symptoms
◦ Giardiasis is the most frequently diagnosed intestinal
parasitic disease in the United States and among
travelers with chronic diarrhea.
◦ Signs and symptoms may vary and can last for 1 to 2
weeks or longer . In some cases, people infected
with Giardia have no symptoms
◦ Acute symptoms include
◦ Diarrhea
◦ Gas
◦ Greasy stools that tend to float
◦ Stomach or abdominal cramps
◦ Upset stomach or nausea/vomiting
◦ Dehydration (loss of fluids)
◦ Flatulence
◦ Other, less common symptoms include itchy skin,
hives, and swelling of the eye and joints .
◦ Sometimes, the symptoms of giardiasis might seem to
resolve, only to come back again after several days or
weeks.
◦ Giardiasis can cause weight loss and failure to absorb
fat, lactose, vitamin A and vitamin B12.
◦ In children, severe giardiasis might delay physical and
mental growth, slow development, and cause
malnutrition.
◦ Giardia trophozoites are attracted to bile salts: so
sometimes you can get infections in bile ducts and
gall bladder, causing jaundice.
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11. Treatment and Prognosis
◦ Several drugs can be used to treat Giardia infection. Effective
treatments include metronidazole, tinidazole, and nitazoxanide .
Alternatives to these medications include paromomycin, quinacrine, and
furazolidone
◦ Drug of choice is Flagyl, Metronidazole: 15mg/kg/day in 3 divided dose
for 5-7 days.
◦ Giardia thrives in people- not necessarily hard to treat , but keeping
those who were infected from becoming reinfected.
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12. Diagnosis
◦ Test a sample of stool.
◦ For accuracy, you may be asked to submit several stool samples
collected over a period of days.
◦ The samples are then examined in a lab for the presence of parasites.
◦ Stool tests may also be used to monitor the effectiveness of any
treatment you receive.
◦ At least 3 exams (one every other day) before judge negative.
◦ ELISA tests: detect soluble antigen.
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13. Precaution
◦ Clean and disinfect your home
◦ Use safe, uncontaminated water to wash all food that is to be eaten raw.
◦ Avoid eating raw or uncooked foods when traveling in countries with poor
food and water treatment.
◦ Do not drink untreated water from lakes, rivers, springs, ponds, streams, or
shallow wells.
◦ If the safety of drinking water is in doubt (for example, during or after an
outbreak, in a place with poor sanitation or lack of water treatment systems),
do one of the following:
◦ Drink bottled water.
◦ Disinfect tap water by heating it to a rolling boil for 1 minute.
◦ Use a filter that has been tested and certified for cyst reduction.
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14. REFERENCES
◦ Adams, Rodney. “The Biology of Giardia spp.” Microbiological Reviews. Dec 1991: 706-732.
◦ 2. “Anton van Leeuwenhoek.” Wikipedia.com. 21 May 2006.
<http://en.wikipedia.org/wiki/Anton_van_Leeuwenhoek>.
◦ 3. Beach, Michael. “CDC Travelers’ Health: Yellow Book, Giardiasis.” 23 May 2006.
<http://www2.ncid.cdc.gov/travel/yb/utils/ybGet.asp?section=dis&obj=giardiasis.htm&cssNav=browseoyb>.
◦ 4. Dobell, C. “A protozoological bicentenary: Antoy van Leeuwenhoek (1632-1723) and Louis Joblot (1645-1723).”
Parasitology. 15 (1932): 308-319.
◦ 5. Dykes AC, Juranek DD, Lorenz RA, Sinclair S, Jakubowski W, Davies R. “Municipal waterborne giardiasis: an
epidemilogic investigation. Beavers implicated as a possible reservoir.” Annals of Internal Medicine. (1980)
Feb;92:165-70.
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15. THANK YOU
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