Giardia lamblia (AKA Giardia intestinalis or Giardia duodenalis )

1. Giardia lamblia(AKA Giardia intestinalis or Giardia duodenalis)

2. cosmopolitan, monoxenous human parasite, which inhabits small intestine (duodenum) and bile ducts • trophozoites attach to surface of the epithelial cells with special „adhesive disc” and they cause some pathological changes of intestinal mucous membrane

3. MORPHOLOGY • it forms bi-nucleate trophozoite and cyst • trophozoite: oval orpear-shaped, 12-15 µm long, 5-15 µm wide • cyst: ovoid, 8-12 µm by 7-10 µm in size

4. AD – ventral adhesive (sucking) disc • Nu – two nuclei • k – kariosome • Ax – two axonemes (serves as the "skeleton”) • Fg – four pairs of flagella • MB – two large median bodies (unique to the species of Giardia)

5. FOUR PAIRS OF FLAGELLA in trophozoite

8. CW – cyst wall (with cytoplasm retracted away form the CW) • Nu – nuclei (two in young cysts, four when matured) • k - kariosome • Ax - axoneme • MB – median bodies (4 in fully mature cysts)

10. EPIDEMIOLOGY • most common in the warm climate • the prevalence may be up to 25% in various population groups in some temperate areas • it infects nearly 2% of adults and 6% to 8% of children in developed countries worldwide, while nearly 33% of people in developing countries have had giardiasis

11. children are more susceptible than adults! • several animals may serve as reservoir host of this parasite • domestic animals may transmit dieases directly to humans, however the type of Giardia that infects humans is usually not the same type that infects dogs and cats • it is found mostly in different water sources: lakes, streams

13. the infective stage for humans is CYST • cysts are passed in the feces and, in contrary to trophozoites, they can remain viable for months in extrenal environment (like water) • an infected person might shed 1-10 billion (usually 300 milions) cysts daily in the feces and this might last for several months • HOWEVER, swallowing as few as 10 cysts might cause someone to become ill

14. SOURCES OF INFECTION ARE MAINLY: food (vegetables) and water contaminated with cysts – indirect transmission • Giardia may be passed person-to-person or even animal-to-person (very rarely!) - direct transmissionby hand to mouth (oral route) • symptoms of giardiasis normally begin 1 to 3 weeks after a person has been infected

15. LIFE CYCLE

17. DISEASE • is called giardiasis/ giardiosis • signs and symptoms may vary and can last for 1 to 2 weeks or longer • in most cases it is asymptomatic giardiasis is the most frequently diagnosed intestinal parasitic disease in the US and among travelers with chronic diarrhea

18. Acute symptoms include: • diarrhea and gas • light colored, greasy stools • stomach or abdominal cramps and pains • dehydration (loss of fluids) • upset stomach or nausea/vomiting • loss of weight (failure to absorb fat, lactose, vitamin A and B12)

19. other, less common symptoms include: itchy skin, swelling of the eye and joints, and nervous complaints • in children, severe giardiasis might delay physical and mental growth, slow development, and cause malnutrition (anaemia) • sometimes, the symptoms of giardiasis might seem to resolve, only to come back again after several days or weeks

20. DIAGNOSIS • direct microscopic identification of: • cysts in stool (smear of feces, permanent stained fecal smears, by means of concentration techniques) • trophozoites in loose stool • trophozoites in the duodenal contents (with Enterotest capsule)

21. ENTEROTEST

22. cysts of G. lamblia in stained stool specimen

25. trophoziotes of G. lamblia

28. TREATMENT • several drugs can be used to treat Giardia infection • effective treatments include metronidazole and tinidazole • alternatives to these medications include paromomycin, quinacrine and furazolidone

29. PREVENTION • the ways of prevention are: • high level of social sanitation • proper personal hygiene • boiling only drinking water • consumption exclusively of clean food • treatment of infected persons as humans acts as reservoirs for the infection

30. Tapeworms = Cestodes SEGMENTED WORMS

31. tapeworms exhibit a great variety of sizes: • D. latum: up to 10 m (even more in big animals) • T. solium: 2-8 m • T. saginata: 4-10 m • E. granulosus: 3-6 mm

32. the body always consists of: • a scolex • a neck • the stobila (proglottids)

33. the scolex may be equipped with three types of attaching organs: • suctorial grooves = BOTHRIA • cup-like sucking disks = ACETABULARIA • hooks

36. the cestodes are all hermaphroditic organisms ! • each individual proglotid contains a complete set of reproductive organs: both male and female - meaning each segment can produce fertilized eggs! • although these develop at different rates, with the male organs usually developing first (protandry phenomenacharacteristic for tapeworms)

37. the different morphology and life cycles determine the distinction of two tapeworm groups Cestoda Pseudophyllidea Cyclophyllidea • Diphyllobothrium sp. • Taenia sp. • Echinococcus sp. • Hymenolepis sp.

38. LIFE CYCLES

39. tapeworms require one or more intermediate host (with the exeption of Hymenolepis nana) • the intermediate host may be of different taxonomic group (from arthropods to mammals), while the definitive host is a vertebrate

40. life cycle begins when the segments of the tapeworm break off and pass through in the feces • each segment contains eggs that hatch out in the feces

41. tapeworms’ eggs • Diphyllobothrium • latum Taenia sp.

42. the eggs (containing oncosphere) are eaten by an intermediate host and develop into larvae (different types of larva!)

43. a mature tapeworm develops in the intestine of the definitive host after eating of the tissues of infected intermediate host containing larvae

46. MAN MAY SUFFER BOTH AS THE DEFINITIVE HOST AND THE INTERMEDIATE HOST OF TAPEWORMS

47. Taenia saginata = beef tapeworm

48. MORPHOLOGY • may measure up to 10 m in length • consists of about 800 proglottides (immature, mature and gravid) • pear-shaped scolex is equipped with 4 suckers without rostellum or hooks • gravid proglottide is rather longer than wider and filled with characterictic branched uterus