Microbiology, Parasitology

1. PHYLUM PLATYHELMINTHES

2. CLASS CESTODEA/CESTODA
• Intestinal parasites of humans and other
vertebrates.

5. Form and Functions
1. Body consist of an anterior attachment
organ:
a. SCOLEX- Head at the anterior end , equipped
with hold fast organ to maintain the position of
the parasite in the gut of the host.
TYPES:
ACETABULUM- cup shaped, circular or oval in
outline and with heavy muscular wall; normally
4 per scolex.

6. SCOLEX TYPES
BOTHRIDIA- Muscular , projecting sharply from
scolex with leaf-like margins. (in Group of 4)
BOTHRIA- Consist of shallow pits or longer
grooves. (usually 2 up to 6)

7. Form and Functions
b. PROGLOTTIDS
c. NECK- Between scolex and proglottid;
contains germinal cells that are responsible for
budding of new proglottids.
d. STROBILA- Consist of a linear series of sets or
reproductive organs of both sexes; each set is
known as the GENITALIUM

9. GENITALIUM
a. APOLYSIS-When mature proglottids detaches
and passed intact out the host.
b. PSEUDOAPOLYSIS/ ANOPOLYSIS- Eggs
released through gravid segment through
uterine pore; segment detaches only when
senile or exhausted.
c. HYPERPOLYSIS- Segments shed while
immature and lead independent existence.

10. Form and Functions
2. Lacks digestive tracts; absorbs all required
substance via their tegument with microtriches.
3. Nervous system is primarily confined in the
scolex, composed of complex set of ganglia with
connecting commisures.
4. Monoecious, usually protandric, some are
gynandric.

11. ORDER PSEUDOPHYLLIDEA
• Have scolex with dorsal and ventral
longitudinal grooves: BOTHRIA
• Life cycle involve:
First Intermediate Host- Crustaceans
Second Intermediate Host- Fish

13. Family Diphyllobothrium latum
- Broad fish Tapeworm
- Common in fish eating carnivores particularly
in Northern Europe
- Lack host specificity; Occours in many canines
and felines, mustelids, pinnipeds, bears and
humans.

14. Mustelids

18. MORPHOLOGY
• Can reach to a length of 10 meters and can
shed in the region of one million eggs per day
• Anapolytic which means they shed their spent
proglottids.
• Scolex is finger-shaped with bothria on the
dorsal and ventral surfaces.
• Proglottids are wider than they are long in
numerous testis and vittellaria.
• With bilobed ovary

19. PATHOGENESIS
• Assmptomatic or have poorly defined
symptoms
• Non-specific abdominal symptoms:
- Vague abdominal discomfort
- Diarrhea
- Weakness
- Nausea
- Pernicious Anemia

20. DIAGNOSTICS
- Fecalysis – Demo of characteristic egg in the
stool
TREATMENT
- Niclosamide;Inhibition of an inorganic
phosphate ATP exchange reaction associated
with worms metabolism.
- Praziquantel
- Aspidium Oleoresin

21. SPARGANOSIS
• Has been reported to occur in many countries
but it is most common in eastern Asia.
• Human become Intermediate Host
INFECTION OCCURS IN SEVERAL WAYS:
- Drinking water infected with copepods
- Eating raw undercooked second Intermediate
host.
- Parasite can penetrate the skin (Broken skin)
- Direct contact with Infected vertebrates

22. SPARGANUM LARVA
• Wrinkled, whitish ribbon-shaped organism, a
few mm and up to several cm long.
• Cxommon site is subcutaneous tissue and
fascia of;
Abdominal Wall
Thoracic Wall
Lower Limbs
Neck & Scrotum

23. Symptoms
• Cerebral Sparganosis: Headache, generalized
seizure, Hemiparesis, Dysarthria, Tonic/Clonic
seizure, Hemianopsia, Focal Seizure, Mental
retardation.
• Subcutaneous Sparganosis: Palpable mass
that is migrating or fixed, Indolent, redness,
Itchy; can be complicated by abscess
formation and cutaneous hemorrhage.

26. TREATMENT
• Surgical removal
• Praziquantel

27. ORDER CYCLOPHYLLIDEA
• With single, compact vitelline gland
• Scolex with 4 suckers
• Rostellum armed with hooks
• Tapeworm of birds and mammals

28. Family Taeniidae
• Where the largest cyclophyllideans are
• Mammals serve as intermediate host
• Rostellum is armed and non retractable;
numerous testes; bilobed mass ovary near the
posterior end .

29. Taeniarrhyncus saginatus
• “Beef tapeworm”
• Most common taeniid in humans
MORPHOLOGY
Lack rostellum or any scolex armature
10-15 feet (can reach 75 ft.) as many as 2000
proglottid each worm
With four powerful suckers, followed by long
slender neck.

32. CYTICERCUS/ BLADDER WORM
• White, pearly; 10 mm in diameter with single
invaginated scolex causes Cysticercosis Bovis
• Cysticercus can survive for several years in the
animal.
• Human become infected by ingesting raw or
undercooked infected meat.
• In human intestine, the cysticercus develops
over 2 months into adult tapeworm and can
survive more than 30 years.

33. PATHOLOGY
• Adult worms in humans cause no serious
symptoms
Vague abdominal discomfort
Hunger pains
Chronic indigestion/ dispepsia
Loss of appetite
Verminous intoxication
Dizziness, Headache, Abdominal pain, Nausea

34. Diagnosis
• Fecalysis
– Egg identification and examination of the scolex or
gravid proglottid.

35. Tainea solium
• “Pork Tapeworm”
• Most potentially dangerous to humans,
possibly of self infection with cysticerci.
Morphology:
Adult with non retractable scolex with 2 circles
of 22-23 hooks
Scolex is spheroid and smaller
Strobila: 6 to 10 ft. cans reach as long as 30 ft.

37. CYSTICERCOSIS
• Infection occurs when the tapeworm larvae
enter the body and form cysticerci:
a) Ingestion of food, water contaminated with
pork tapeworm egg, or putting contaminated
fingers to mouth .
b) Person who has a tapeworm infection can
reinfect themselves; gravid proglottid may
migrate from lower intestines to stomach or
doudenum.

38. Once inside the stomach , the tapeworm egg
hatches , penetrates the intestine, travels
trough blood stream and may develop into
cysticerci in the subcutaneous tissue, muscles,
brain, eyes, heart, liver, lungs.

40. TYPES
• SUBCUTANEOUS CYST
– Easily palpated, lipomas
• Management (surgical removal)
• OCULAR CYSTICERCOSIS
– May cause irreparable damage to retina, iris uvea or
choroid.
– Visual difficulties that fluctuate with eye position
– Decrease in visual acuity
– Retinal detachment, edema, hemorrhage, or vasculitis

41. SUBCUTANEOUS CYST

42. OCULAR CYSTICERCOSIS

43. • NEUROCYSTICERCOSIS (NCC)
– Symptoms are vague, rarely diagnose except in
autopsy
– Clinical manifestations are:
• Seizures (80%)
• Headache (40%)
• Visual changes (20%)
• Confusion (15%)
• Ataxia (5%), (Psychosis 5%)
• S/S of Hydrocephalus
• Decrease GCS
• Increase ICP

45. • MUSCLES
– Majority are asymptomatic
– May give rise to MYOSITIS with accompanying
fever and eosinophilia
– PSEUDOHYPERTROPHY- Rare because of
autoimmune response
• Process- Swelling then leading to atrophy then become
fibrotic.

47. • DIAGNOSIS
– Imaging study: CT scan, MRI
– Serum analysis- Presence of cysticercosis antibody
• False positive in some places that are endemic
– CSF analysis

48. TREATMENT
• Plaziquantel
• Albendazole
• Prednisone- to supress excessive immune
response
• Hydrocephalus- VP shunt
CONTROL
Sanitation- Universal precaution
Cooking pork meat properly
Proper storage of meat

49. Echinococcus multilocularis
• Boreal in distribution: In Europe, Asia, North
America.
• ADULT- Parasites of foxes (Felines, Coyotes
and Canines may also serve as definitive host)
• HYDATID CYST: In small rodents also wolves,
lemmings and mice.

50. • Characteristics:
– 1.2-1.3 mm long
– 15-30 testes located posterior to cirrus pouch
– Hydatid larvae: with thin outer wall that grows
and infiltrates processes into sorrounding host
tissue: ALVEOLAR or MULTILOCULAR HYDATID
– In humans, pieces of the cyst sometimes breaks
off and metastasize to other parts of the body.
– Dogs are the most common source of infections to
humans.

52. E. vogeli
• Parasites of canids in Central and South
America
• Rarely cause hydatidosis in humans; but dogs
are the source of human infection.
• Polycystic (alveolar) in humans but produce
relatively large, fluid filled vesicles with
numerous protoscolices
• Natural intermediate host: Rodent (Paca)

54. GENUS ECHINOCOCCUS
• Pathogenesis: Hydatidosis
– Depend on type and extent of pathology
– Hydatid effects may not be apparent for many yrs.
(up to 20 yrs.)
– As size of hydatid increases it crowds adjacent
host tissues and interferes with their normal
developmental functions

56. • In Bone Marrow
– Growth restricted to internal space resulting to
chronic internal pressure necrosis of bone; bone
becomes thin and fragile leading to spontaneous
fracture.
• In Unrestricted Areas:
– May become enormous, accumulate a large
amount of fluid (HYDATID FLUID) may rupture,
cause sudden death.

57. • Anaphylactic shock:
– Protienaceous hydatid fluid induces adverse host
reaction.
• Pulmonary Cysts:
– When ruptures in bronchioles severe allergic
reaction symptoms and coughing with production
of blood flecked fluid.

58. • Diagnosis
– Routine medical x-ray, UTZ
– Surgical exploration and aspiration for possible
hydatid sand
– Serological test: ELISA, IHA, EIA, IFA
• Treatment
– Surgery
– Albendazole

59. Family Hymenolepidea
• Small number of testes (1-4)
• Unilateral genital pores
• Large external seminal vesicle

60. Vamperolepsis nana
• Dwarf tapeworm
• Probably the most abundant tapeworm in the
world commonly found in young children
• Infection rates vary widely with less than 1% of
the North American population being infected,
while other Hot spots specially developing
countries estimated that over 90% of the
population are infected.
• Produces only mild symptoms of intestinal
discomfort.

61. • Morphology:
1. Adult: Approximate length 35mm. The
tapeworms body (strobilla) consist of
proglottids in various stages of development
• The scolex has four suckers and an armed
retractable rostellum with only one row of hooks
(about 20-30 hooks)
• Neck long and slender , proglottids are wider than
long
• Genital pores, unilateral, each mature segment with
3 testes

62. 2. Egg: 40-70 um in diameter; with presence of
polar filaments in t6he area between the
outside shell and the internal larva.
3. Oncosphere: Covered with thin, outer hyaline
membrane and an inner thick membrane
with polar thickenings with several
filament.

64. • PATHOLOGY
– Little pathology associated with this parasite unless it
trough autoinfection.
• Symptoms:
– Abdominal Pain
– Diarrhea
– Headache and dizziness
– Anorexia
– Various non specific symptoms
– TREATMENT
• Niclosinamide
• Praziquantel