SCHISTOSOMIASIS -- AETIOLOGY 'EPIDEMIOLOGY ' ,PATHOPHYSIOLOGY ,SYMPTOMS AND SIGNS ,LABORATORY DIAGNOSIS ,TREATMENT

1. SCHISTOSOMIASIS
DR OGECHUKWU
MBANU
FAMILY MEDICINE
DEPARTMENT
AKTH, KANO
17TH MAY 2018

2. OUTLINE
• INTRODUCTION
• HISTORY
• EPIDEMIOLOGY
• ETIOLOGY
• LIFE CYCLE
• PATHOGENESIS
• CLINICAL MANIFESTATION
• CLINICAL EVALUATION
• TREATMENT
• PROGNOSIS
• PREVENTION
• CONCLUSION

3. Intorduction
• Caused by schistosomes( blood flukes)
• A Platyhelminthes
• In class trematode
• Snail fever or bilharzia
• Occurs mainly in rural agricultural and periurban areas
• Infection occurs after contact with water that contains
the infective stage (cercaria) of schistosomes
• The disease is most commonly found in Africa, Asia and
south America
• Ranks second behind malaria in public health
importance in tropical and subtropical areas of the
world

4. History
• Once known as bilharzia.
• Named after Theodore Maximillian Bilharz
• 1st to describe urinary schistosomiasis in
man in 1851 at kasr-el- aini in Cairo, Egypt
• S. Haematobium, first species to be
discovered.
• S. Mansoni, discovered in 1907
• 1st doctor to describe the entire disease cycle
was Pirajá da Silva in 1908

5. HISTORY CONT’D
• S. Japonicum, named by fijiro katsurada,
professor of medicine at Okayama medical
school.
• Schistosome eggs were found in ancient
Chinese and Egyptian mummies by Sir
Armand Ruffer in 1910
• S. Intercalatum, officially named in 1934
• S. Mekongi, officially named in 1978.
• Katayama fever named after the province of
Katayama in Hiroshima Japan

6. EPIDEMIOLOGY
• Widely distributed in tropical and sub
tropical regions
• > 200 million people infected world wide
• > 600 million at risk of infection
• About 280,000 deaths annually
• On a global scale 1 in every 30 individual
has schistosomiasis
• Amongst parasite infections second only
to malaria in its global impact

8. ETIOLOGY
SPECIE REGION
S. mansoni Sub-Saharan Africa , middle
east, Turkey , India
S.Japonicum China , Japan , Philippines ,
Thailand , Indonesia
S. Intercalatum Central Africa , West Africa
S . haematobium Africa and Middle east
S. mekongi Laos , Cambodia ,
S. guineensis West Africa
S. malayensis Peninsula Malaysia

9. Etiologic agent:the pathogen
• Separate sexes.
• The large male (0.6 to 2.2 cm × 2 to 4
mm)
• Female (1.2 to 2.6 cm × 1 to 2 mm)
• Has more than 2 Testes
• The male has a ventral gynecophoric
canal in which the female is held
• Definitive host- humans
• Intermediate host- fresh water snail
• Reservoir hosts – cows ,pigs
,(S.Japonicum) ,rodents, monkeys, and
baboons
• Forked cercaria is the infective stage.

10. S .HEAMATOBIUM FEMALE
S.Heamatobium male S. haematobium couple
EGG

11. EGG OF S.MANSONI WITH LATERAL SPINE
S. MANSONI IN COPULA
S.MANSONI IN COPULA AND MALE FORM

12. MALE OF S.JAPONICUM
OVA OF S.JAPONICUM SPINELESS

13. Etiologic agent : The intermediate Host
BULINUS
TRUNCATUS(S.
heamatobium)
BIOMPHALARIA
ALEXZANDRINA(mansoni)
S Japonicum

14. Forms of schistosomiasis
Intestinal schistosomiasis
• Intestinal and liver pathology
• S.mansoni,S. japonicum ,(S. intercalatum
, S. guineensis ,S. mekongi )
Urinary schistosomiasis
• urogenital system pathology
• S. heamatobium

16. Schistosomiasis :lifecycle

17. PATHOGENESIS 1

18. PATHOGENESIS 2

19. PATHOGENESIS 3

20. IMMUNOPATHOGENESIS
• Immune response to the presence of the
ova causes almost all the pathology and
chronic complications in schistosomiasis
• Acute schistosomiasis can cause severe
febrile illness in humans
• Substances released from the ova are toxic
to human tissue e.g. can cause hepatotoxic
ity

21. IMMUNOPATHOGENESIS cont’d
 Soluble carbohydrate antigens from the ova
are presented by Antigen presenting cell to naïve
T cells (To)
 This leads to proliferation of both Th1 and Th2
CD4+ T cells
 Th1 produces IFN gamma, IL 2, TNF alpha
 IFN gamma recruit and help in activation of the
macrophages
Activated Macrophage produces PDGF ,
TGF beta , TNF , IL 1 , IL 6

22. IMMUNOPATHOGENESIS cont’d
 Th2 response is dominant at the chronic stage
although Th1 response persist.
 Th2 response may also be due to ova proteins t
hat
cause mast cell to produce IL 4 which induces fu
rther Th2 differentiation and amplifies the respo
nse.
 Th2 produces IL 3, 4 , 5 ,13
 IL 13 increases fibrosis by increase in synthesis
of
proline an important amino acid in collagen

24. CLINICAL PRESENTATION 2
Worm maturation : - katayama sydrome
• 2 – 8 weeks after skin penetration.
• Systemic allergic reaction to eggs antigens : fever ,
chills , rigors , myalgia ,arthralgia ,
lymphadenopathy ,hepatomegaly ,
• Usually lasts days or weeks , then resolves ,
• Severe cases: shock , coma , death
• In S .japonicum , cerebral schistosomiasis can
occure 1.7 to 4.3% , Usually as early as 6 weeks
after infection

25. Clinical presentation 3 – chronic schisto
S.Heamatobium :painless terminal heamaturia is a classic
symptom
• Urinary urgency ,incontinence ,
• There could be obstruction Granulomas at the lower end of
the ureters obstruction  hydroureter and hydronephrosis
• Female genital tract lesions  infertility ,increased risk of HIV
acquisition
• Urethral ulcerations ,Bladder polyposis
• Fistulae between urinary tract and skin watering can
scrotum
• Bladder fibrosis , calcification , Squamous cell CA of the
bladder
• In the lungsfocal pulmonary arteritis and pulmonary HTN

26. Clinical presentation 4 - chronic scisto
S.mansoni/S.japonicum : asymptomatic for a long time
until late complications
• abdominal pains , irregular bowel movements ,
hematochezia ,
• Firm hepatomegaly ,liver fibrosis (SYMMERS PIPE
STEM fibrosis involving the portal vessels and
periportal spaces), liver failure
• Splenomegaly with left upper quadrant pain
• Ascites , jaundice , Portal hypertension
• Esophageal varices  heamatemesis  anemia
• Colonic polyposis
• Pulmonary hypertension

27. CLINICAL EVALUATION
Clinical
evaluation
History
physical
examination
General
physical
Systemic
physical
Laboratory
tests

28. HISTORY
• Biodata of patient
• Presenting complaints
• History of presenting complaints
• Developmental history
• Past medical and surgical history
• Obstetrics and gynecological history
• Drug history
• Family and social history
• Immunization history
• Travel history

29. PHYSICAL EXAMINATION
• General physical examination
• Systemic physical examination

30. LABORATORY INVESTIGAIONS
• Diagnosis in high and low endemic areas
• Direct and indirect methods
• low endemic : tests used have high sensitivity
and specifity in order to find even light infections
• Direct methods  detection of eggs,
• Indirect methods  detection of specific
antibodies and antigens
• Stool sample – S.mansoni and S.japonicum
• urine sample – S.heamatobium
• Acute cases may be negative for eggs

31. Detection of Schistosoma haematobium
• urine dipstick heamaturia and/ or proteinuria,
• Gross heamaturia indicates heavy infection
• Two methods are used for detection of eggs
Sedimentation method and
Filtration Method
• Sedimentation method is less sensitive cheaper
and simpler to perform.
• Filtration method is used for quantitative analysis
for epidemiological surveillance purposes

32. Materials needed
• Microscope slides and coverslips
• Centrifuge (sedimentation method)
• Conical centrifuge tubes, 15 ml (sedimentation
method)
• Filter holder, 13 or 25mm diameter (filtration method)
• Membrane filter, 12–20mm pore size (nylon or
polycarbonate)
• Conical flask for urine collection
• Pipettes (sedimentation method)
• Plastic syringe, 10 ml (filtration method)
• Lugol iodine, 0.5% solution (filtration method)
• Formaldehyde, 37% solution

33. Collection of urine specimens
• Collected between 10am – 2pm
• Consists of a single terminal urine
specimen of at least 10 ml
• Alternatively, a 24-hour collection of
terminal urine
• Containers should be wide-mouthed,
clean and dry.

34. Collection of urine specimens cont’d
• Examine the specimen at once
• If the urine cannot be examined for an hour
or longer, add 1 ml of undiluted formalin
(37% formaldehyde solution) to each 100
ml of urine.
• This will preserve any eggs that might be
present.
• If formalin is not available, 2 ml of ordinary
household bleach can be added to each 100
ml of urine.

35. Sedimentation method
• Shake the well and pour into the conical
flask.
• Allow the urine to sediment for 1 hour.
• Remove the supernatant and transfer the
sediment into a centrifuge tube.
• Centrifuge at 2000rpm for 2 minutes.
• Examine deposit with microscope for the
presence of ova

36. SEDIMENTATION METHOD CONT’D
• IMPORTANT:
• Do not increase the centrifugation time and
do not exceed 2000rpm
• This may disrupt the ova and release
miracidia
• process the specimen as soon as possible;
• shake container before pouring the urine
specimen into the conical flask;
• label slides and tubes carefully

37. Filtration method
• Place a filter in the filter holder.
• Agitate sample gently and draw 10ml into the
syringe
• Attach the syringe to the filter holder.
• Expel the urine from the syringe through the
filter over a container
• Disconnect the syringe from the filter holder
• Draw air into the syringe
• reattach the syringe to the filter holder
• expel the air through the filter

38. FILTRATION METHOD CONT’D

39. Filtration method cont’d
• Disconnect the syringe from the filter holder.
Using forceps,
• Remove the membrane filter or filter-paper
and place it on a microscope slide.
• The nylon membrane and filter-paper should
be placed face-up
• while the polycarbonate membrane should
be placed face-down.
• Add one drop of Lugol iodine solution to
improve the visibility of the eggs.

40. FILTRATION METHOD CONT’D
• Examine the entire filter under the
microscope at x10 or x 40.
• Record the results as the number of eggs
per 10 ml of urine.
• Reporting the result
• Light infection: 1–49 eggs per 10 ml of
urine.
• Heavy infection: > 50 eggs per 10 ml of
urine.

41. STOOL EXAMINATION
• Stool examination is done
Macroscopically and
Microscopically
MACROSCOPICALLY
• Colour: brown, pale
• Consistency : formed ,semi-formed , watery
• Odour: shigella ,amoebiasis may have
offensive odour
• Presence or absence of mucous or blood

42. STOOL EXAMINATION – PRECAUTIONS
• Never leave stool specimens exposed to the
air in containers without lids.
• Never accept stool specimens mixed with
urine (e.g. in a bedpan)
• Always examine stool specimens within 1–4
hours after collection.
• If several specimens are received at the same
time, examine the liquid stools and those
containing mucus or blood first, as they may
contain motile amoebae (which die quickly).

43. MICROSCOPY (remains the gold standard)
microscopy
Concentration
method
Sedimentation
method
Floatation
method
Kato katz
method
Wet
mount(direct
,quick) metho
Unstained
method
Stained with
iodine and
eosin

44. WET MOUNT – UNSTAINED
ITEMS NEEDED
• Gloves
• Labelled
microscopic slide
• Cover slip
• Stool sample
• Normal saline
• Wooden
stick/spatula
• Pipette
• microscope
Procedure
• Add one drop of normal
saline with pipette to slide
• Pick a tiny amount of stool
sample with stick
• Put the stool sample on the
slide and mix thoroughly
with the stick
• Apply cover slip making
sure no air bubbles
• Examine under the
microscope

45. Floatation method
Permits separation of eggs by the use of liquid with
high specific gravity
Items needed:
• Zinc sulphate
• Iodine solution
• 15ml conical centrifuge tube
• Plastic pipettes
• Tongue depressor
• Funnel and plastic beaker
• Slides and cover slips

46. Floatation method cont’d
• With the tongue depressor take ½ to
1gram of stool, add to the plastic beaker
and close the sample container
• With the pipette add 7ml of zinc sulphate
into the plastic beaker and mix well
• Transfer into the centrifuge tube using
the funnel and fill up with more zinc
sulphate

47. Floatation method
 
 

48. FLOATATION METHOD CONT’D
• Close tube and centrifuge
• With the pipette collect a little from the
surface and drop on the slide
• Add one drop of iodine,mix well with
wooden stick
• Cover with cover slip then view under the
microscope

49. Floatation method cont’d







50. Sedimentation method
ITEMS NEEDED
• Gloves
• 10% formalin
• Acetyl acetate solution
• Iodine solution
• 15ml conical centrifuge
tube
• Tongue depressor
• Plastic pipette
• Microscopic slides
• Cover slide
• Wooden spatula
• Gauze and funnel
• Plastic beakker
PROCEDURE
• with tongue depressor,
collect stool sample,put
inside the plastic beaker
• With the pipette add
3ml of 10% formalin to
the plastic beaker
• Mix well and transfer
into the centrifuge tube
through funnel coated
with gauze

51. PROCEDURE – SEDIMENTATION cont’d
• Wash the gauze with 10% formalin then
remove gauze
• Add 3ml of acetyl acetate using pipette
and put into the centrifuge tube
• Cover centrifuge tube and mix well
• Open the tube fast and close fast to
allow some gas to escape
• Centrifuge at 2000rpm. Add another
tube to create balance

52. SEDIMENTATION cont’d
• Remove the supernatant ,leaving few drops of
sediment emulsion on ,close tube and shake
well
• Add drop of sediment on glass slide with the
pipette
• Add a drop of iodine and mix well with
wooden spatula
• Put a cover slip on the slide , avoiding air
bubbles
• View under the microscope

53. kato katz method
ITEMS NEEDED
Kato and Miura in 1954
cellophane thick-smear technique
1. Glass slides
2. Cellophane (25×30 mm)
3. 50% glycerol
4. a Piece of paper
5. Nylon screen (sieve)
6. Coverslips with hole in the
middle
7. Pipettes
8. Stick
9. Gloves

54. KATO KATZ CONT’D
• Transfer a small amount of faeces onto a piece of
paper(scrap paper )
• Soak the cellophane strips (25×30 mm) in 50%
glycerol malachite green Solution for at least 24
hrs before use.
• Press the screen on top of faecal specimen
• Using a plastic spatula, scrap across the upper
surface of the screen to sieve the faecal sample
• Transfer a small amount of the sieved faecal
material into the hole of the template & carefully
fill the hole. Level with the applicator stick

55. KATO KATZ CONT’D

56. KATO KATZ CONT’D
• Remove the template carefully so that all the
faecal material is left on the slide &none is left
sticking to the template.
• Cover the faecal sample on the slide with the
glycerol-soaked cellophane strip,
• wipe off excess glycerol with a small piece of
toilet paper.
• Invert the microscope slide & press faecal
sample against cellophane on a smooth surface
to spread sample evenly
• Examine under microscope

57. KATO KATZ CONT’D

58. KATO KATZ CONT’D
• Used for determination of intensity of infection in
endemic areas
• Kato – Katz method may need to be repeated (3x –
different days)
• The cover slip template delivers 41.7mg of feaces
• Number of eggs observed is multiplied by 24 to get
the number of eggs per gram of feaces
QUANTITATIVE ANALYSIS
Light infection 1 – 100eggs/gram feaces
Moderate infection 100 – 400 /gram feaces
Heavy infection >400 eggs / gram feaces

59. Egg viability test
• Used to assess the effectiveness of treatment
• Persons with inactive infection may continue to shed
eggs into stool and urine for months
DONE BY :
1. Egg hatching test
2. Microscopic Examination of eggs for flame cells
• Stool or urine is mixed with distilled water at room
temperature
• It is the observed for hatching of the miracidium or
movement of the flame cells
• There are four flame cells, one at each corner of the
embryo.
• Use a x100 objective (slightly reduced illumination)
• look for the rapid movement of cilia (short hairs) in the
flame cells.

60. Test for viability wih the hatching test
Living egg Dead egg
• Opaque
• Dead miracidium non
motile silent
• No RBCs
• Does not hatch in fresh
water(negative hatching
test)
• Transluscent
• Intact moving
miracidium contracting
and relaxing
• Surounded by RBCs
• Hatches in fresh water
(positive hatching test)

61. OTHER INVESTIGATIONS
• FBC– eosinophilia , anemia , Thrombocytopenia(due
to splenic sequestration)
• Blood cultures – for salmonella bacteremia (a
Salmonella urinary tract infection should always
lead to suspicion of schistosomiasis
• S /E/U/Cr
• Lumbar puncture – eosinophilia , antischistosomal
antibodies
• LFT – Mild  alkaline phosphatase and
gammaglutamyl transferase
levels usually are within the reference range until the
end stage of disease

62. OTHER INVESTIGATIONS CONT’D
• SEROLOGY – Falcon assay screening test (FAST),
enzyme-linked immunoassay (ELISA), and
immunoblot assays
 Detection of antibodies to ADULT WORM
MICROSOMAL ANTIGENS(MAMA ,HAMA ,JAMA)
• Antigen Tests – they reflect active infection
circulating anodic antigen (CAA) and
 circulating cathodic antigen (CCA).
These antigens can be found in urine or serum.
Still investigational
• Urine deepstick detection of parasite antigens

63. OTHER INVESTIGATIONS CONT’D
IMAGING STUDIES
• Plain abdominal radiography – bladder , ureteral
calcifications("fetal head" calcification)
• Ultrasonography – Hydronephrosis ,
hydroureters, bladder wall irregularities
periportal fibrosis , hepatosplenomegaly and
ascites
• Urography – abnormalities in ureter bladder wall
• Intravenous pyelography (IVP) - Ureteric stricture
• Barium swallow or Endoscopy - Esophageal
varices

64. OTHER INVESTIGATIONS CONT’D
• CT or MRI scan -interstitial fibrosis. Calcified liver
capsules and septal , lesions in CNS schistosomiasis.
• Echocardiography – pulmonary hypertension due
to egg emboli to pulmonary vasculature
BIOPSY AND OTHER PRROCEEDURES
• Biopsy is helpful when stool sample findings are
negative or in light infection e.g.
– liver biopsy (unclear diagnoses or suspected co-
infections) ,
– mucosal biopsy
• Cystoscopy , Bronchoscopic washings ,
transbronchial biopsies ,upper GI endoscopy

65. TREATMENT
• Praziquantel
• Derivative of pyrazinoisoquinoline
• High efficacy, affordable
• Lack of serious short –term and long – term side
effects
• Usually given as single dose
• Effective against adult worms >6wks post infection
• 40 mg /kg - S.mansoni ,S.heamatobium
• 60mg/kg in 2 or3 divided doses in a single day –
S.japonicum
• Side effects includes : fever , nausea & vomiting ,
headaches, dizziness, drowsiness, pruritus, fatigue

66. Prognosis
• Almost all patients improve with treatment.
• Most patients with early disease or without
severe end-organ complications recover
completely.
• Resolution of pulmonary disease is less well
documented.
• Co-infection with malaria, HIV, or hepatitis
worsens the prognosis
• Patients with heavier worm burdens are less
likely to improve and are more likely to
require re-treatment

68. CONCLUSION
• Schistosomiasis can be associated with serious
morbidity and mortality.
• Chronic complications are generally seen in
those with a high parasite load, which usually
occurs in individuals who live in endemic areas
and have recurrent exposure
• There is every need to capture patients early
so to give better quality of life.

69. REFERENCE
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Tropical Countries Part 1 Second Edition Cambridge University
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