Treatment of Schistosomiasis
Praziquantel is the drug of choice for all forms of schistosomiasis, with specific dosing regimens based on the infecting Schistosoma species. 1
Standard Treatment Regimens
- For Schistosoma mansoni, S. intercalatum, and S. guineensis infections: Praziquantel 40 mg/kg orally as a single dose 1
- For Schistosoma japonicum and S. mekongi infections: Praziquantel 60 mg/kg orally in two divided doses 1
- For S. hematobium infections: Praziquantel 40 mg/kg orally as a single dose 2
- For infections diagnosed by serology alone from the Asia-Pacific region: Praziquantel 60 mg/kg orally in two divided doses 1
Special Clinical Scenarios
Acute Schistosomiasis (Katayama Syndrome)
- Presents 2-9 weeks after exposure to contaminated water, characterized by fever, eosinophilia, urticarial rash, and other symptoms 3
- Treatment approach:
Neuroschistosomiasis
- For CNS involvement: Praziquantel 40 mg/kg twice daily for 5 days 1
- Combine with dexamethasone 4 mg four times daily, reducing after 7 days, for a total of 2-6 weeks 1
- In acute neuroschistosomiasis, administer corticosteroids before anthelmintic therapy 1
Diagnostic Considerations
- Concentrated stool microscopy is recommended for all patients returning from the tropics with eosinophilia 3
- For S. hematobium, terminal urine samples should be examined 3
- During acute schistosomiasis (Katayama syndrome), serology and stool/urine microscopy have low sensitivity 3
- Clinical diagnosis can be made with the combination of fresh-water exposure 4-8 weeks previously, fever, urticarial rash, and eosinophilia 3
Treatment Efficacy and Monitoring
- Standard cure rates with praziquantel are typically >70% 4
- However, some studies have reported lower cure rates (18-38%) in certain regions, raising concerns about potential resistance 4
- In high-intensity infections, cure rates may be lower, with moderate or heavy infections cleared in only half or one-third of individuals, respectively 5
- Total egg count reduction with standard treatment is approximately 61.4-96.6% 5, 6
- Serology may remain positive for many years after successful treatment and cannot be used to assess treatment success 1, 2
Common Pitfalls to Avoid
- Failing to adjust dosage based on Schistosoma species can lead to treatment failure 1
- Administering praziquantel during acute Katayama syndrome without steroids may worsen symptoms 1
- Using serology alone to assess treatment success is unreliable as antibodies persist for years 1
- Consider potential co-infection with strongyloidiasis before starting corticosteroids, which could precipitate hyperinfection syndrome 1
- In non-endemic areas, some clinicians use higher doses or multiple treatments, though this is not part of standard guidelines 7