1. Intestinal Helminths Dr MONA BADR

2. CLASSIFICATION OF PARASITES
PROTOZOA
HELMINTHS
Unicellular
Single cell for all functions
Multicellular
Specialized cells
1:Aoebae: move by pseudopodia.
2:Flagellates: move by flagella.
3:Ciliates: move by cilia
4:Apicomplexa(Sporozoa)
tissue parasites
Round worms (Nematodes):
- elongated, cylindrical,
unsegmented.
Flat worms :
- Trematodes: leaf-like,
- Cestodes: tape-like,
segmented.

3. Nematodes: Location in the human body
Intestinal nematodes
Tissue nematodes

4. Nematodes : General features
Elongated worm, cylindrical, unsegmented and tapering at both ends.
Variable in size, measure <1 cm to about 100cm.
Sex separate and male is smaller than female

5. Nematodes: common intestinal infections
Common intestinal nematode infections:
Enterobius (Oxyuris) vermicularis (Pinworm,seatworm,threadworm)
Trichuris trichiura (whipworm)
Ascaris lumbricoides (roundworm)
Ancylostoma duodenale & Necator americanus (hookworms)
Strongyloides stercoralis :

6. 1-Enterobius vermicularis (THREAD WORM)
(Common names :Pin worm, seat worm, (
Found all over the world but more common in temperate regions and in Saudi Arabia.
Children are more often involved than adults , it tends to occur in groups living together such as families , army camps or nursery.
Adult worms are mainly located in lumen of cecum and the female migrate to rectum to deposits her eggs on the anus and perianal skin.
.Adult worm can be seen by naked eye as white thread ± 1cm.
Male is smaller than female ± 0.5cm, with coiled end. .

7. Life cycle and transmission
. Person-to-person transmission can occur by eating food touched by contaminated hands with eggs or by handling contaminated clothes or bed linens. In addition, eggs may become airborne, inhaled, and swelled.
Autoinfection occurs by scratching the per anal area and transferring infective eggs to the mouth with contaminated fingers .
Life cycle: Following ingestion of the contaminated food, eggs hatch and release larvae in the small intestine. The adult worms establish themselves mainly in the cecum and appendix. The time interval from ingestion of infective eggs to oviposition by the adult females is about one month. Each female worm can produce 10,000 or more eggs.
Gravid females migrate (having eggs) through the rectum onto the per anal skin to deposit eggs; this usually occurs at night. The larvae inside the eggs generally mature within four to six hours, resulting in infective eggs. The eggs begin to lose infectivity after one to two days under warm and dry conditions but may survive more than two weeks in cooler, more humid environments.

9. Clinical manifestations of pin worm
Majority of infections are asymptomatic.
The most common symptom of enterobiasis is perianal itching, also known as pruritus ani ,which
can be very troublesome and occurs more often during the night, persistent itching may lead to inflammation and secondary bacterial infection of the perianal region . Infected children may suffer from emotional disturbance ,insomnia ,anorexia , loss of weight and loss of concentration and enuresis, also adult worm can lodged in the lumen of appendix cause appendicitis in heavy infection.
Ectopic enterobiasis occurs in infected adult female when larva invade vulva and vagina result in valvovagintis, salpingitis .

10. Treatment ِِAlbandazole , Mebendazole for whole family
Enterobius vermicularis (Oxyuris)
DIAGNOSIS :
Unlike other intestinal Nematodes, the eggs are not usually found in feces .The best method is to look for them around the anus by taking an anal swab or by using CELLULOSE ADHESIVE TAPE, the examination should be done before defecation or bathing.
Treatment
ِِAlbandazole , Mebendazole
for whole family

11. Enterobius vermicularis (pin worm)

12. Ascaris lumbricoides (roundworm)

13. Ascaris lumbricoides (roundworm)
The commonest human helminthes infection all over the world.
The large round worm which is normally located in the small intestine.
Found in jejunum and upper part of ileum.
Female ± 20 cm longer than male ± 10 cm
Feed on semi digested food.

14. Ascaris lumbricoides life cycle

15. Life cycle of Ascais Lumbricoides
It infect the human when man ingest an emberyonated egg contaminated with food or water, then the Larva hatch from the emberyonated egg and penetrate the wall of the duodenum and enter the blood stream to the heart ,liver and enter the pulmonary circulation and stay in the alveoli ,where it grow and molts for three weeks then Larva passes from respiratory system to be coughed up ,swallowed ,returned to the small intestine where it mature to adults male &female ,fertilization take place producing fertilized (diagnostic stage ) eggs per day, which pass in stool and has to stay in soil for2 to4weeks to become emberyonated infective stage eggs.

16. a
Ascaris lumbricoides

17. CLINICAL MANIFESTATIONS :
1-Migrating LARVA :
Ascaris pneumonia , some times LARVA reach aberrant sites like brain ,heart or spinal cord can cause unusual disturbance granuloma. Loeffler`s syndrome ,pneumonitis with bronchospasm
, cough with bloody sputum with esinophilia.
2-Adult WORM:
The worm consumes proteins and vitamins from host’s diet and leads to malnutrition.
Can cause intussusception, intestinal ulcers and in massive infection can cause intestinal obstruction and bile duct obstruction.

18. Ascaris eggs diagnostic stage.
(embryonate) infective stage

19. Ascaris lumbricoides (roundworm)
Loeffler`s syndrome: Larvae in lung
pnumonia,cough ,bloody sputum

20. Ascaris lumbricoides (roundworm)
Diagnosis:
-eggs (fertilized) in stool.
-larvae in sputum.
-adult may pass with stool.
Treatment: Albendazole , Mebendazole

21. 2-Trichuris trichiura (Whipworm)

22. Trichuris trichiura (whipworm)
World wide ,common in poor sanitation.
It coexists with Ascaris because of similar requirement (soil).
Adult live in large intestine especially caecum and appendix –in heavy infection the whole length of large intestine affected.
Male and female worm have narrow anterior portion penetrate the intestinal mucosa

23. Trichuris trichiura (Whipworm)

24. Life cycle and transmission The life cycle for trichuriasis begins with passage of unembryonated eggs in the stool . In the soil, the eggs become embryonated and become infective in 2 to 4 weeks. After ingestion of contaminated food or water with soil containg emryonated eggs, in the small intestine the larvae will hatch and become mature into adult worms, which become established in the cecum and ascending colon after two to three months.
The adults measure approximately 4 cm in length. The females begin to produce eggs 60 to 70 days after infection and shed 3000 to 20,000 eggs per day. The life span of the adults is one to three years

25. Trichuris trichiura (Whipworm)
CLINICAL MANIFESTATIONS :
light infection : asymptomatic
heavy infection :abdominal pain ,bloody diarrhea. Colitis & Rectal prolapse in children is a common complication.
-Diagnosis: egg in stool characterized by its barrel shape with mucoid plugs at each pole .
Treatment :Albendazole.

26. Ancylostoma dudenale &Necator americanus
Hook worms
Ancylostoma dudenale &Necator americanus
Buccal cavity attached to intestinal mucosa

27.  LIFE CYCLE of hook worm
There are two species of hookworm that cause human infection: Ancylostoma duodenale (in Mediterranean countries and the Far East) &Necator americanus (in North and South America, Central Africa). The hookworm life cycle begins with passage of eggs with stool from an adult host . The eggs hatch in the soil to release rhabditiform larvae that mature into infective stage filariform larvae. Infection is started by larval penetration into human skin, then larvae migrate into the blood vessels and are carried to the lungs,  Approximately 8 to 21 days following infection, larvae penetrate into the pulmonary alveoli, ascend the bronchial tree to the pharynx, and are swallowed, In the small intestine, the larvae mature into adult worms and attach to the intestinal wall with resultant blood loss causing severe iron deficiency anemia .

28. Hook worms Ancylostoma dudenale &Necator americanus

29. Ancylostoma dudenale &Necator americanus
Hook worms
Ancylostoma dudenale &Necator americanus
CLINICAL MANIFESTATIONS : Cutaneous manifestations  Dermal penetration of the skin frequently produces a focal pruritic maculopapular eruption at the site of larval penetration ( ground itch).
Transpulmonary passage  A mild cough and pharyngeal irritation may occur during larval migration in the airways, though eosinophilic pulmonary infiltrates (such as those seen in Ascaris) cough with bloody sputum and pneumonia.  
Acute gastrointestinal symptoms  Nausea, diarrhea, vomiting, midepigastric pain.
Chronic nutritional impairment Hookworms cause blood loss during attachment to the intestinal mucosa by ingesting blood causing sever iron deficiency anemia , impaired nutrition & hypoproteinaemia .

30. Diagnosis and treatment
Hook worms
Diagnosis and treatment
Stool examination
-Eggs in stools.;
-occult blood (+) Eosinophilia : as well in any parasitic infection  
Treatment: Albendazol, Mebendazole

31. Strongyloides stercoralis
Strongyloidiasis is caused by infection with Strongyloides stercoralis. Manifestations of infection can range from asymptomatic eosinophilia in the immunocompetent host to disseminated disease with septic shock leading to death in the immunocompromised host Strongyloidiasis is endemic in tropical and subtropical regions ,it is the smallest nematode . LIFE CYCLE :  The Strongyloides life cycle is more complex than that of most nematodes with its alternation between free-living and parasitic cycles, and its potential for autoinfection and multiplication within the host

32. Strongyloides stercoralis
LIFE CYCLE

33. Strongyloides stercoralis
Free-living cycle: The rhabditiform larvae passed in the stool  can either molt and become infective filariform larvae or molt and become free living adult males and females  and produce eggs  from which rhabditiform larvae hatch . Which can either develop  into a new generation of free-living adults , or into infective filariform larvae can penetrate the human host skin to initiate the parasitic cycle

34. Strongyloides stercoralis
Parasitic cycle: Filariform larvae in contaminated soil penetrate the human skin , and are transported to the lungs where they penetrate the alveolar spaces; they are carried through the bronchial tree to the pharynx, are swallowed, and then reach the small intestine . In the small intestine they molt and become adult female worms . The females live in the epithelium of the small intestine and produce eggs , which become rhabditiform larvae. The rhabditiform larvae can either be passed in the stool  , or can cause autoinfection . In autoinfection, the rhabditiform larvae become infective filariform larvae, which can penetrate either the intestinal mucosa (internal autoinfection) or the skin of the perianal area (external autoinfection); in either case, the filariform larvae may follow the previously described route, being carried successively to the lungs, the bronchial tree, the pharynx, and the small intestine where they mature into adults; or they may disseminate widely in the body. To date, occurrence of autoinfection in humans with helminthic infections is recognized mainly in Strongyloides stercoralis mainly in immunocompromised host.

35. Strongyloides stercoralis: Pathology and clinical picture:
Cuteneous little reaction on penetration ,sever dermatitis .
Migration :same as hook worms .
Intestinal: inflammation of upper intestinal mucosa, diarrhea, upper abdominal pain colicky in nature.
Disseminated strongyloidiasis : in patient with immunodeficiency ,uncontrolled diarrhea –granulomatus changes –necrosis--perforation--peritonitis--death.  The massive dissemination of filariform larvae to the lungs, liver, heart, central nervous system, and endocrine glands induces inflammation that may result in symptomatic dysfunction of these organs and even septic shock.

36. Strongyloides stercoralis
Diagnosis:
rhabditiform larvae diagnostic stage in:
-Stool examination
-Aspiration of duodenojejunal fluid. In disseminated strongyloidiasis, filariform larvae can be found in stool, sputum, bronchoalveolar lavage fluid, pleural fluid, peritoneal fluid.
Treatment : Albandazole, Mebendazole

37. Common Tapeworm Infections
DISEASE
TRANSMISSION
OF INFECTION
LOCATION OF ADULT
IN HUMANS
LOCATION
OF LARVA
CLINICAL PICTURE
LAB.
DIAGNOSIS
Taenia saginata
taeniasis
ingestion of larva in undercooked
beef
Small
Intestine
not present
vague digestive disturbances
eggs or
proglottids
in stools
Taenia solium-
ADULT
pork
LARVA
(cysticercus cellulosae)
Cysticercosis
ingestion of egg
not present (except in
autoinfection:
,small intestine)
sub-cutaneous
muscles
brain,eyes
depending on
locality:
from none to
epilepsy
X -ray,CT,MRI
Serology
Hymenolepis nana
hymenolepiais
Intestinal
Villi
Enteritis
diarrhoea
eggs in
stools
Echinochoccus
granulosus
hydatid disease
Liver, lungs,
Bones etc
locality
X-ray,CT,US
Hydatid sand
TAPEWORM

38. Taeniasis — There are two main species of Taenia for which humans are the only defenitive host   T. saginata, T. solium.

40. Taeniasis 
Clinical manifestations — Most human carriers of adult tapeworms are asymptomatic. patients may pass proglottids in or eggs in stool (T. solium) or (T. saginata) or may notice segments in their stool or sense the movement of proglottids through the anus. There may be associated symptoms including nausea, anorexia, or epigastric pain. Anxiety, headache, dizziness, and urticaria can also occur. A peripheral eosinophilia may be observed.
Occasionally, segments can enter the appendix, common bile duct, or pancreatic duct and cause obstruction Diagnosis — The diagnosis is generally established by identifying eggs or proglottids in the stool of the only host (human).

41. Life cycle of
Taenia solium

42. Pathology and clinical feature of cysticercosis
Infection by ingestion the egg of Taenia Solium then the larvae will hatch and cause (cysticercosis). Cysticercosis generally multiple, may occur in any site but are more frequent in the brain and muscle. They excite reaction in the area ,as inflamation ,fibrosis and later some calcification. This leads to focal CNS syndromes especially epilipsy.

43. Hymenolepiasis Hymenolepis nana (dwarf tapeworm)

45. Hymenolepis nana

46. Life cycle of Echinococcus granulosus

47. Location of hydatid cyst
Echinococcus granulosus

48. life cycle — The life cycle of echinococcus includes a definitive host (usually dog) and an intermediate host (such as sheep, goats, camels, cattle, and swine) . Humans are incidental hosts; they do not play a role in the transmission cycle. E. granulosus a dult tapeworms are usually found in dogs .

49. Location of hydatid cyst of
Echinococcus granulosus
Mainly in the liver lung ,brain,bone, heart.

50. Liver hydatid cyst

52. Treatment of Tapeworms
Intestinal stages: Praziquantel
Tissue stages ( Hydatid , cysticersosis):
Depends on clinical condition : Surgical and/or Albendazole