Entamoeba histolytica
Amoebiasis
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Trophozoites or cysts on stool micro (cannot distinguish between cysts of E. histolytica/dispar/ moshkovskii). Multiplex PCR distinguishes spp
May be associated with GIT symptoms, including colitis
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FBE/differential
Fresh stool <24 h for ELISA or PCR if available. If E dispar confirmed - nothing. If E histolytica confirmed treat.
If ELISA/PCR not available, serology (IHA) for E. histolytica, although baseline positive 30% endemic areas.
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Asymptomatic: eliminate intraluminal carriage
Paramomycin 10mg/kg/dose (max 500mg) 8 hourly oral 7 days (SAS medication)
Symptomatic: Discuss with ID. Metronidazole 15mg/kg/dose (max 600mg) tds oral 7 days followed by luminal agent (as above). Higher doses in severe disease/confirmed liver abscess.
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Offer screen |
Discuss with ID physicians if symptomatic |
As required for parasite persistence or reinfection |
| Ascaris lumbricoides |
Ova on stool micro History macroscopic worms May be a/w respiratory symptoms |
FBE/differential
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Albendazole (weight >10kg) 400mg oral stat (200mg oral stat if >6 months, <10kg)
Mebendazole 100mg oral bd 3 days (50mg oral bd 3 days if <10kg)
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Offer screen, Rx siblings |
Repeat stool micro at follow-up (not essential) |
As required for parasite persistence or reinfection |
| Giardia duodenalis |
Trophozoites or cysts on stool micro
May be associated with GIT symptoms. Asymptomatic carriage in immune competent may not need treatment.
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nil
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Metronidazole 30mg/kg (max 2g) oral daily for 3 days OR 10mg/kg (max 400mg) oral 8-hourly for 3 days
Tinidazole discontinued in 2020. Nitazoxanide, albendazole, mebendazole or paromomycin are alternatives
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Screen symptomatic family |
Repeat stool micro at follow-up (not essential) |
As required for parasite persistence or reinfection |
| Hookworm Ancylostoma or Necator |
Ova on stool micro |
FBE/differential
Ferritin
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Albendazole (weight >10 kg) 400mg oral stat (200mg oral stat if >6 months, <10kg)
Mebendazole 100mg oral bd 3 days (50mg oral bd 3 days if <10kg)
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Offer screen |
Repeat stool micro at follow-up |
As required for parasite persistence or reinfection |
| Strongyloides stercoralis
(Risk of dissemination if immune suppressed) See guideline |
Strongyloides serology is primary screen Larvae on stool micro |
Strongyloides serology
FBE/differential
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Ivermectin (weight >15 kg) 200mcg/kg (no upper limit) x 2 doses, day 1 and day 14 (2 weeks apart). More doses if immunocompromised
Albendazole (weight >10 kg) 400mg oral bd for 3 days + repeat course after 14 days (200mg oral bd as above if >6 months, <10kg) less effective than ivermectin
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Offer screen |
If larvae on stool micro then repeat 3 days post treatment
Serology & FBE at 6 months
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If parasites persist on stool micro
If serum IgG & eosinophilia persist at 3-6 months
Children <15kg may require monitoring & Rx with ivermectin once 15kg
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| Clear positive IgG |
Fresh stool micro
FBE/differential |
| Pulmonary or GIT symptoms |
Discuss with ID consultant urgently |
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Schistosoma
(Bilharzia)
see guideline
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Schistosoma serology is primary screen (more sensitive for S. mansoni & S. haematobium than others) Ova on stool micro |
FBE/differential
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Praziquantel 20mg/kg x 2 doses oral, 4 hrs apart (no upper limit) 40mg/kg total may be given as a stat dose in children
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Offer screen |
If initial stool or urine micro+ repeat at 3-6 months (x 3 specimens)
FBE/differential at 3 months Serology at 12 months
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Persistent parasite, increasing IgG titre 6 months post Rx (especially if eosinophillia)
IgG same at 12mo
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If positive serology - check stool COP and end urine If positive stool or urine, further investigations for end-organ damage
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Midday end urine micro for ova (lab x5738 first)
Renal/bladder US (urinary) or liver US & doppler (gut)
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Tapeworm
T. solium (pig) or T. saginata (beef) |
Proglottids or ova in faeces
Nodules
Check neurological symptoms/epilepsy Hx (T. solium, different Rx)
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FBE/differential
Ferritin
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Praziquantel 10mg/kg oral stat (no upper limit) Niclosamide 50mg/kg (max 2g) oral stat
Hymenolepis (Rodentolepis) nana (dwarf tapeworm) - Praziquantal 25mg/kg oral stat (no upper limit)
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Offer screen |
Repeat stool micro at 3 weeks - not essential. |
As required for parasite persistence or reinfection |
| Whipworm Trichuris trichiuria |
Ova stool micro
May be associated with bloody diarrhoea, pain or rectal prolapse
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FBE/differential
Ferritin
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Mebendazole 100mg oral bd 3 days (50mg oral bd 3 days weight <10kg)
Albendazole 400mg oral daily for 3 days (200mg oral daily for 3 days >6m, weight <10kg)
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Offer screen |
Repeat stool micro at 3 weeks - not essential |
As required for parasite persistence or reinfection |
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Note:
- Praziquantel - Australian guidelines now providing dosing for children 1-18y (although limited evidence <4 years, some trials age 2-5 years) - discuss with Infectious diseases for younger children. Arpraziquantel has recently been approved in Europe for children >5kg - trials in children 3 months - 6 years (150mg dispersible tablets)
- Albendazole tabs are chewable and soluble, WHO recommends as preventive therapy in children 12 months - 12 years (as annual or biannual 400mg dose) where baseline prevalence of soil transmitted infection is 20%+. Biannual dosing recommended if baseline prevalence is >50%. Discuss if liver disease
- Ivermectin is used in children >15 kg
- Exclude pregnancy in adolescents; Praziquantal B1, Metronidazole B2, Ivermectin B3, Albendazole D.
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