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WHO Essential Medicines Library - EMLib

Cestodes (tapeworm) - echinococcosis

Introduction, etiology

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Most cases of echinococcosis (hydatid disease) in humans are caused by two species of the Echinococcus tapeworm:
- E. granulosus, the cause of cystic echinococcosis, which is maintained worldwide in a domestic transmission cycle involving dogs and livestock, mainly sheep;
- E.multolocularis, the cause of alveolar echinococcosis, which is endemic in the northern hemisphere in foxes, dogs and other carnivores and field rodents.

When eggs excreted by infected animals are ingested by humans they hatch in the intestine to release invasive oncospheres. These, according to the species, develop further by either expansion (cystic echinococcosis) or infiltration (alveolar echinococcosis) in the liver, lungs or other organs. The clinical sequelae of cystic echinococcosis usually result from pressure, but rupture of a cyst can involve allergic reactions. Alveolar echinococcosis, particularly in the liver, can become metastatic and is frequently fatal.

In echinococcosis, although surgery is still the treatment of choice for operable cystic disease due to Echinococcus granulosus chemotherapy with benzimidazoles, such as mebendazole and albendazole , may be of value as adjunctive therapy. Alveolar echinococcosis due to E. multilocularis requires both surgery and long-term treatment with either mebendazole or albendazole to inhibit metastatic spread.

In animal studies, albendazole and mebendazole have been found to be teratogenic. They are contraindicated for the treatment of cestode infections in pregnancy; pregnancy should be excluded before treatment with albendazole (non-hormonal contraception during and for 1 month after treatment). For single dose or short-term use in pregnancy

Recommended treatments

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The treatment of choice for operable cystic disease due to E. granulosus is surgery, or the PAIR treatment (Puncture, Aspiration, Injection, Re-Aspiration), see reference below.

Alternative in inoperable cases:
albendazole .html chewable tablet, 400 mg	.html Adults: Up to four 30-day courses of 10-15 mg/kg daily in two divided doses separated by treatment-free periods of 15 days.
or mebendazole .html chewable tablet, 100 mg, 500 mg	.html Adults: 4.5 g daily in three divided doses for 6 months

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Patients with E.multilocularis infections may need further treatment cycles. Alveolar disease due to E.multilocularis may require both surgery and long-term treatment with either mebendazole or albendazole to inhibit metastatic spread.

References

1. .html
Model Formulary search, enter 'cestode' and see Cestode infections.

http://mednet3.who.int/eml/modelFormulary.asp

2. .html
PAIR: Puncture, Aspiration, Injection, Re-Aspiration: An option for the treatment of Cystic Echinococcosis WHO/CDS/CSR/APH/2001.6

http://www.who.int/emc-documents/zoonoses/whocdscsraph20016.html

3. .html
Zoonoses and other animal and food related public health risks, Publications and documents, 1981-1999, WHO/CDS/CSR/APH/2000.1

http://www.who.int/emc-documents/zoonoses/docs/whocdscsraph2001.pdf

4. .html
Food safety issues associated with products from aquaculture, WHO Technical Report Series 883, 1999.

http://www.who.int/foodsafety/publications/fs_management/aquaculture/en/

5. .html
Cestode infections, WHO references

http://www.who.int/emc/diseases/zoo/vphpublications/cestode_infections.html

6. .html
WHO Model Prescribing Information. Drugs used in parasitic diseases second edition, 1995. 146 pages [E, F, S] ISBN 92 4 140104 4 Sw.fr. 35.-/US $31.50. In developing countries Sw.fr.24.50.
Note: Where there is discrepancy between this book and the WHO Model Formulary, the Formulary should be considered to be the more authoritative.

Sales Information: http://www.who.int/bookorders/index.htm

7. .html
Report of the WHO Informal Consultation on the use of praziquantel during pregnancy/lactation and albendazole/mebendazole in children under 24 months, Geneva, 8-9 April, 2002, WHO/CDS/CPE/PVC/2002.4

http://www.who.int/wormcontrol/documents/en/pvc_20024full.pdf

8. .html
Benzimidazoles: use in children, Essential Medicines, WHO Drug Information, Vol 17, No. 1, 2003

http://www.who.int/druginformation/vol17num1_2003/vol17-1.pdf

1.	.html Model Formulary search, enter 'cestode' and see Cestode infections.
	http://mednet3.who.int/eml/modelFormulary.asp
2.	.html PAIR: Puncture, Aspiration, Injection, Re-Aspiration: An option for the treatment of Cystic Echinococcosis WHO/CDS/CSR/APH/2001.6
	http://www.who.int/emc-documents/zoonoses/whocdscsraph20016.html
3.	.html Zoonoses and other animal and food related public health risks, Publications and documents, 1981-1999, WHO/CDS/CSR/APH/2000.1
	http://www.who.int/emc-documents/zoonoses/docs/whocdscsraph2001.pdf
4.	.html Food safety issues associated with products from aquaculture, WHO Technical Report Series 883, 1999.
	http://www.who.int/foodsafety/publications/fs_management/aquaculture/en/
5.	.html Cestode infections, WHO references
	http://www.who.int/emc/diseases/zoo/vphpublications/cestode_infections.html
6.	.html WHO Model Prescribing Information. Drugs used in parasitic diseases second edition, 1995. 146 pages [E, F, S] ISBN 92 4 140104 4 Sw.fr. 35.-/US $31.50. In developing countries Sw.fr.24.50. Note: Where there is discrepancy between this book and the WHO Model Formulary, the Formulary should be considered to be the more authoritative.
	Sales Information: http://www.who.int/bookorders/index.htm
7.	.html Report of the WHO Informal Consultation on the use of praziquantel during pregnancy/lactation and albendazole/mebendazole in children under 24 months, Geneva, 8-9 April, 2002, WHO/CDS/CPE/PVC/2002.4
	http://www.who.int/wormcontrol/documents/en/pvc_20024full.pdf
8.	.html Benzimidazoles: use in children, Essential Medicines, WHO Drug Information, Vol 17, No. 1, 2003
	http://www.who.int/druginformation/vol17num1_2003/vol17-1.pdf