What is the recommended treatment for schistosomiasis?

Treatment of Schistosomiasis

Praziquantel is the drug of choice for all forms of schistosomiasis, with dosing of 40 mg/kg as a single oral dose for most species (S. mansoni, S. haematobium, S. intercalatum, S. guineensis), but 60 mg/kg divided into two doses for S. japonicum and S. mekongi infections. 1

Standard Treatment Regimens by Species

For S. mansoni, S. haematobium, S. intercalatum, and S. guineensis

• Administer praziquantel 40 mg/kg orally as a single dose 1
• This regimen is effective for infections from Africa, the Middle East, and South America 1

For S. japonicum and S. mekongi

• Administer praziquantel 60 mg/kg orally divided into two doses on the same day 1
• This higher dosing is specifically required for infections from the Asia-Pacific region 1
• For any infection diagnosed by serology alone from the Asia-Pacific region, use the 60 mg/kg divided dose regimen 1

Repeat Dosing Strategy

• Repeat praziquantel treatment at 6-8 weeks after initial therapy because eggs and immature schistosomulae are relatively resistant to treatment 2, 1
• This interval allows any surviving immature worms to mature into adults that are susceptible to praziquantel 3

Acute Schistosomiasis (Katayama Syndrome)

This presents 2-8 weeks after freshwater exposure with fever, cough, urticarial rash, diarrhea, and marked eosinophilia 2, 1

Treatment Algorithm for Acute Disease

1. Start with prednisolone 20-30 mg daily for 5 days first to reduce symptom duration and prevent worsening from parasite death 1
2. Administer praziquantel 40 mg/kg after the acute inflammatory phase subsides 1
3. Give a second dose of praziquantel 6-8 weeks later to treat any worms that were immature during initial treatment 1

Critical Pitfall to Avoid

• Never give praziquantel during acute Katayama syndrome without corticosteroids first, as killing parasites during the acute inflammatory phase can worsen symptoms 1
• Screen for strongyloidiasis before starting corticosteroids to prevent hyperinfection syndrome 1
• Avoid dexamethasone if possible, as it increases praziquantel metabolism and reduces drug levels 1

Neuroschistosomiasis

For CNS involvement, a more intensive regimen is required:

• Administer praziquantel 40 mg/kg twice daily for 5 consecutive days 1
• Combine with dexamethasone 4 mg four times daily, reducing after 7 days, for a total duration of 2-6 weeks 1
• In acute neuroschistosomiasis, give corticosteroids first before starting anthelmintic therapy 1

Treatment Failure or Persistent Infection

If eggs persist at 6 weeks post-treatment:

• Repeat praziquantel 40 mg/kg (or 60 mg/kg for Asian species) 6-8 weeks after initial treatment 3
• The 6-8 week interval is critical because it allows immature parasites that survived initial treatment to mature and become susceptible 3
• Consider adding prednisolone 20 mg daily for 5 days if acute symptoms are severe 3

Monitoring and Follow-up

• Do not use serology to assess treatment success, as antibodies persist for years after cure 1, 3
• Use microscopy of stool (for S. mansoni, S. japonicum) or terminal urine (for S. haematobium) to detect eggs and confirm active infection 3
• Serology is useful for initial diagnosis but cannot distinguish active from past infection 1

Common Pitfalls to Avoid

• Do not use 60 mg/kg dosing for African or South American species (S. mansoni, S. haematobium)—this higher dose is reserved only for S. japonicum and S. mekongi 3
• Do not fail to adjust dosage based on species, as this leads to treatment failure 1
• Do not treat too early after initial therapy—wait the full 6-8 weeks before repeating treatment to allow immature worms to mature 3
• Do not rely on serology alone to assess cure, as antibodies persist indefinitely 1, 3

Special Populations

• For pregnancy, lactation, or immunocompromised patients, seek specialist advice for dosing adjustments 1
• Praziquantel is generally safe with only minor and transitory side effects reported 4