Schistosomiasis: A Common Diagnosis in Tanzania

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Schistosomiasis A Common Diagnosis in Tanzania

• Anna Person, MD
• PGY-3

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43 year old male presents to Kilimanjaro
Christian Medical Centre in Moshi, Tanzania

• One week of melena
• Progressive abdominal distension
• One day of hemetemesis
• No hx of fever, cough, diarrhea
• Works as a farmer in the rice paddies
• No past medical history
• No medications

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Exam

• BP 86/50, HR 121, Temp 36.5 C, RR 21
• Thin male in mild distress
• HEENT- pale conjunctiva
• CV- regular rate and rhythm, no murmurs
• Pulm- clear to ascultation bilaterally
• Ab- distended, dullness to percussion, palpable,
  enlarged liver and spleen
• Ext- no edema

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Studies

• Hb- 5, Hct- 15
• Abdominal US- markedly enlarged spleen, somewhat
  enlarged liver, heterogenous in appearance
• Endoscopy (available at KCMC)- bleeding
  esophageal varices identified

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Schistosomiasis

• Trematode infecting over 200 million worldwide1
• Transmitted through skin while wading in
  freshwater
• S. hematobium (Africa and Middle East) ? kidney
  and bladder
• S. mansoni (Africa, ME, Carribean, S. America),
  japonicum (Asia), mekongi (Asia)? liver

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Life Cycle of Schistosomes
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Life Cycle

• Females produce eggs which release larvae into
  water
• Larvae seek out snails and become sporocyts and
  then cercarial larvae
• Cercarial larvae leave the snail and penetrate
  intact skin of humans

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Transmission

• www.humanillnesses.com/.../Schistosomiasis.html

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Transmission, cont.

• Once in humans they become schistosomulae
• These migrate into the arterial circulation
• Then they reach the liver and mature into adults
  (within 4 weeks)
• Worms can live up to 30 years2

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Acute Schistosomiasis (Katayama fever)

• Usually occurs 14-84 days from initial contact
• Fever, headache, myalgias, bloody diarrhea,
  abdominal pain, hives
• Respiratory symptoms can occur in up to 70 of
  those infected with S. mansoni3
• A clinical diagnosis? antibody titers can take 3
  months to be positive5

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Acute schistosomiasis case report4

• 16 patients between 94-95
• All had been in sub-Saharan Africa
• Dominant symptoms were fever, lethargy
• Symptoms began on average 36 days after exposure
• 14/16 had eosinophilia, 12/16 had negative stool
  microscopy
• All were treated with praziquantel, 8 required
  further courses of tx

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Chronic Schistosomiasis

• Long-term sequelae caused by granuloma formation
  (immune response to antigens from schistosome)6
• Small subset with high burden of organisms (S.
  mansoni and S. japonicum) develop periportal
  fibrosis? causes portal hypertension, esophageal
  varices, etc

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Chronic Schistosomiasis, cont.

• S. hematobium infections? hematuria, fibrosis of
  bladder and ureters, effects on kidneys
  (protenuria)
• Causes many types of bladder cancer? 75 are
  squamous, 20 are transitional cell, 5 are
  adenocarcinoma, more common in men than women7

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Genitourinary Schistosomiasis a study at KCMC

• Retrospective analysis of pathologic specimens
  from 1999-2005 at KCMC in Moshi, Tanzania8
• Schistosomiasis diagnosed histo-pathologically in
  423 specimens
• 125 of these specimens were found in female
  genitourinary tract (cervix in 71 cases)

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Burden of genitourinary schistosomiasis

• Main symptoms reported were bleeding (48), ulcer
  (17), tumor (20), lower abdominal pain (11),
  and infertility (7).
• Authors conclude that genitourinary schisto is
  underrecognized cause of disease burden in women
  in Moshi, Tanzania

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Diagnosis

• Sometimes a clinical diagnosis if other tests not
  available
• Peripheral eosinophilia can be suggestive
• Microscopic examination of feces and urine for
  eggs? sensitivity unknown
• Serologic tests for antischistosomal antibodies,
  ELISA tests reported to be gt90 sensitive and
  gt95 specific
• PCR not widespread

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Treatment

• Praziquantel.
• 20mg/kg po bid for 1 day (two total doses) for S.
  hematobium, intercalatum, and mansoni
• 20mg/kg po tid for 1 day (three total doses) for
  S. japonicum and S. mekongi9
• Steroids often used w/ praziquantel in acute
  schisto

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Reducing Morbidity

• Burkina Faso, Mali and Niger? annual
  mass-treatments of schoolchildren w/
  praziquantel. In Burkina Faso, prevalence went
  from 90 to lt5 after one year.10
• WHO has adopted a Resolution 54.19, which aims to
  treat 75 of all school-age children at risk for
  morbidity due to schistosomiasis by 201011.

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References

• 1,3 Ross, A et al Current Concepts
  Schistosomiasis. N Engl J Med 3461212, 2002
• 2 Arnon, R. Life span of parasite in
  schistosomiasis patients. Isr J Med Sci 1990
  26404.
• 4,5 Doherty, JF et al. Lesson of the Week
  Katayama fever an acute manifestation of
  schistosomiasis. BMJ 1996313(7064)1071.
• 6 Boros DL, et al. Delayed hypersensitivity-type
  granuloma formation and dermal reaction induced
  and elicited by a soluble factor isolated from
  Schistosoma mansoni eggs. J Exp Med
  1970132488-507.
• 7 Ghoneim MA, Radical cystectomy for carcinoma of
  the bladder critical evaluation of the results
  in 1,026 cases. J Urol. 1997 Aug158(2)393-9.
• 8 Swai, B et al. Female genital schistosomiasis
  as an evidence of a neglected cause for
  reproductive ill-health a retrospective
  histopathological study from Tanzania. BMC
  Infectious Disease 2006, 6134.
• 9 Gilbert et al. The Sanford Guide to
  Antimicrobial Therapy 36th Edition, 2006.
• 10 Garba, A et al. Implementation of national
  schistosomiasis control programmes in West
  Africa. Trends in Parasitology. 2006 July Volume
  22, Issue 7, 322-326.
• 11 http//www.who.int/wer. Weekly Epidemiological
  Record, No.16 2006, 81, 145-164.