Giardiasis (Giardia lamblia)

 

Giardiasis 

(Giardia lamblia)




  • It has “Smiley face" symbol.
  • Found by (Lambl, 1859) Alexeieff, Kofoid & Christiansen, 1915.
  • Causing giardiasis.
  • First seen by Leeuwenhoek (1681) while examining his own stool
  • Flagellated parasitic microorganism.
  • Trophozoites are pear-shaped cells, 10 to 20 µm long, 7 to 10 µm across, and 2 to 4 µm thick.
  • Motile by way of four pairs of flagella.
  • Each G. lamblia cell has two nuclei.

Parasite Stages

Two stages of the parasite

Cyst and trophozoite.


Trophozoites


  • When viewed flat, the shape of the trophozoites is like tennis or badminton racket.
  • When viewed side it resembles a longitudinally split pear shape.
  • The dorsal surface is convex and the ventral surface is concave with a sucking disc.
  • The size of trophozoites 14 µm long and 7 µm broad.
  • The anterior end is broad and the rounded and the posterior end tapers to a sharp point.
  • It is bilaterally symmetrical and all the organs of the body are paired.
  • Colonizes and reproduces in the small intestine.
  • The parasite attaches to the epithelium by a ventral adhesive disc or sucker.
  • Reproduces via binary- fission.


Cyst

  • The mature cyst is oval in shape and measured 12 µm long by 7 µm broad.
  • There are four nuclei which may remain clustered at one end or lie in pairs at opposite poles.
  • The remains of the flagella and sucking disc may be seen inside the cytoplasm.
  • An acid environment often caused the parasite to encyst.

Cyst morphology

  • Cysts are oval-shaped cells slightly smaller than trophozoites.
  • They lack flagella, and are covered by a smooth, clear cyst wall.
  • Each cyst contains the organelles for two trophozoites: four nuclei, two ventral disks, etc




Transmission

Cysts

  • Direct transmission
  • Fomites
  • Contaminated water / food
  • Ingested cysts release trophozoites.
  • Trophozoites multiply and encyst in intestines.
  • Excreted in feces.
  • Swallowing unsafe food or water contaminated with Giardia germs.
  • Having close contact with someone who has giardiasis, particularly in childcare settings.
  • Traveling within areas that have poor sanitation.
  • Transferring Giardia germs picked up from contaminated surfaces (such as bathroom handles, changing tables, diaper pails, or toys) into your mouth.
  • Having contact with infected animals or animal environments contaminated with poop
  • Giardiasis does not spread via the bloodstream,
  • Spread to other parts of the gastrointestinal tract, but remains confined to the lumen of the small intestine
  • Giardia trophozoites absorb nutrients from the lumen of the small intestine, and are anaerobes.
  • Chief pathways of human infection include ingestion of untreated sewage.

 Cyst Survival

  • Survive well in cool, moist conditions.
  • Remain viable for months in cold water (Two months at 8oC and One month at 21oC).
  • Can also survive freezing.
  • Susceptible to desiccation and direct sunlight.

Life Cycle

  • Cysts responsible for transmission
  • Cysts and trophozoites found in feces
  • Ingested by host
  • Importance of animal reservoirs unclear




Symptoms

  • Incubation period: 1-25 days
  • Most infections asymptomatic
  • Symptoms of clinical disease
  • Mild to severe gastrointestinal signs
  • Sudden onset diarrhea
  • Foul-smelling stools, greasy poop that can float.
  • Abdominal cramps, pain,
  • Bloating, flatulence,
  • Nausea, fatigue,
  • Weight loss,
  • Diarrhea,
  • Upset stomach or nausea,
  • Dehydration,
  • Generally, begin by having 2 to 5 loose stools (poop) per day and progressively increasing fatigue.
  • Less common symptoms - fever, itchy skin, hives, and swelling of the eyes and joints.
  • Over time, giardiasis can also cause weight loss and keep the body from absorbing nutrients it needs, like fat, lactose, vitamin A, and vitamin B12.
  • Some people with Giardia infections have no symptoms at all.

Diagnosis

Direct observation in feces

Trophozoites

“Tear drop” shape

Two nuclei and tumbling mobility

Cysts

Approximately 13 microns long

Oval, with 2-4 nuclei

Immunofluorescence and ELISA, PCR.

 Centrifugal Fecal Floatation / Zinc sulfate method

Reagents- Flotation solution (e.g., Zinc sulfate solution or Sheather’s solution), Lugol’s iodine.

  1. Place 1 g faeces into a wide-mouthed plastic disposable cup
  2. Add 4 ml flotation solution to the jar and mix with faeces thoroughly
  3. Add a further 4 ml flotation solution to the jar and mix again
  4. Pour/filter this faecal suspension through a filter into a new jar
  5. Empty the contents of the jar into a 10-15 ml test-tube supported in a rack or stand
  6. Centrifuge at 500 g for 10 min
  7. Carefully add more flotation solution until a positive viscus form at the top of the test tube and place a 22 x 22 mm coverslip on top
  8. Stand for a further 5-10 minutes
  9. Carefully lift the coverslip with the drop of fluid adhered to the bottom of it and place it on a microscope slide. Adding a drop of Lugol’s iodine to the slide before placing the coverslip on it can make the Giardia cysts easier to see
  10. Examine under a light microscope at low power (10x) for helminth stages and at high power (40x) for protozoal stages.


Treatment


Anti-protozoal drugs

Metronidazole

Tinidazole

Ornidazole

Fenbendazole

Albendazole

Chronic cases

May be resistant

Prolonged therapy may be necessary

Metronidazole (Flagyl). Metronidazole is the most commonly used antibiotic for giardia infection. Side effects may include nausea and a metallic taste in the mouth. Don't drink alcohol while taking this medication.

Tinidazole (Tindamax). Tinidazole works as well as metronidazole and has many of the same side effects, but it can be given in a single dose.

Nitazoxanide (Alinia). Because it comes in a liquid form, nitazoxanide may be easier for children to swallow. Side effects may include nausea, gas, yellow eyes and brightly colored yellow urine.

Prevention and Control

Water

  • Do not drink contaminated water
  • Untreated lakes, rivers, shallow wells
  • Treat potentially contaminated water
  • Heat (rolling boil for one minutes)
  • Filter (absolute pore size of one micron)
  • Chlorinate

Food

  • Wash raw fruits and vegetables.
  • Practice good hygiene.
  • Hand washing.
  • Don’t swim in recreational waters for at least two weeks after symptoms end.
  • Avoid fecal exposure,
  • Avoid swallowing water from swimming pools, hot tubs, splash pads, and untreated water from springs, lakes, or rivers (surface water) while swimming
  • Limit environmental contamination.
  • Store, clean, and prepare fruits and vegetables properly.
  • Clean and promptly remove feces from surfaces.
  • Keep pets indoors.

Vaccination

  • Dogs and cats.
  • Use is controversial.


Comments

Post a Comment

Popular posts from this blog

Wine production

Image
  Wine production        Wine  is an alcoholic beverage  typically made from fermented grapes. Yeast  consumes the sugar  in the  grapes  and converts it to ethanol  and carbon dioxide and  releasing heat  in the process. Wine making practice is one of the oldest ancient civilizations. Otherwise called vinification and the study called as oenology.  Archaeological evidence suggests that wine was being made at least 8,000 years ago, and there are indications that viticulture was carried on in Mesopotamia (the region that is now Iraq and eastern Syria) about 5,000 years ago. Wine was a popular beverage as well as a sacred drink. In Greek mythology, Dionysus was the god of wine, overseeing all matters pertaining to the cultivation of grapes and wine production.  The production of wine that begin from crushing of fruits, its fermentation into alcohol and the bottling of the finished alcoholic beverage.  W...
Read more

Fermentation of Soy sauce

Image
  Fermentation of Soy sauce •         It is liquid Condiment of Chinese origin. •     Discovered 2,200 years ago during the western Han dynasty of ancient China and spread throughout East and Southeast Asia and used in cooking as a condiment. •         Soy sauce, with unique clear, deep reddish-brown & liquid consistency. •         Available in different forms such as sauce, liquid or semiliquid mixture. •         Provide flavor, moisture, contrast in texture and color. •        Colour - During the aging of soy sauce, glucose and other sugars combine with amino acids to produce a brown pigment called “Melanoidin”, which gives this beautiful brown color to the soy sauce. •         Smell – Fresh soy sauce, have a live yeast smell and over 300 volatile compounds...
Read more

Cheese production

Image
  Cheese production Cheese is a fermented dairy product with different flavour and texture. It contains about  120 calories, 8 grams (g) of protein, 6 g saturated fat, and 180 milligrams (mg) of calcium . The cheese produced by coagulation of milk protein casein using rennet enzyme. Cow, buffalo, goats and sheep milk are used to make cheese. Milk has two main parts (water and the solids). Whey is the correct name for the liquid. Curds is the correct name for the solids. During cheese making, the bacterial enzymes or rennet are used to make acidification of milk. It causes casein become coagulate and separate whey and curds. The curd called as “Curdling or Clabbering”. The solid curds are then removed by cheese cloth filtration method and drain the whey portion. Herbs, spices and wood smoke also used as flavoring agents to make cheese. Example Lemon, Annatto seed, Cherry, Peppermint, Ginger, Black peppers, Caraway, Garlic, Chives, Cranberries, Aromatic oils (Clove, Spe...
Read more