Cestode Infestations: Hydatid Disease and Cysticercosis
Section snippets
Cystic echinococcosis
Echinococcal cysts comprise the host-derived pericyst, which surrounds the parasite endocyst. The endocyst includes an outer acellular laminated layer and an inner germinative layer. The germinative layer gives rise to brood capsules and protoscolices. Early-stage cysts are filled with clear fluid. With nonsurgical treatments, or sometimes spontaneously, the cystic structures can degenerate (see classification). When ingested by canines, the protoscolices convert to tapeworms. After the rapture
Alveolar echinococcosis (E multilocularis)
Tissue larvae of E multilocularis cause alveolar echinococcosis. In the liver, E multilocularis produces a multivesiculated mass that may liquefy centrally and grows by infiltrating the surrounding tissues. Canines, including foxes and dogs, are the usual definitive hosts. Rodents are the usual intermediate hosts. Humans are incidental intermediate hosts, infected from eggs shed in the environment by the final hosts (eg, dogs).
Definitions
Cysticercosis is caused by infection with the larval stage of T solium. Humans are the obligate definitive host for the intestinal tapeworm. The mature segments termed proglottids produce the ova, which infect pigs (the normal intermediate host) (Fig. 5). In the pig, the ova hatch, release the invasive larvae, which mature into cysticercus within the tissues. The cysticercus consists of a translucent bladder and a mural nodule containing the invaginated scolex. When ingested in undercooked
Treatment
Optimal treatment of neurocysticercosis often includes symptomatic therapy for seizures and hydrocephalus and specific therapy for the parasites (including antiparasitic drugs or surgical removal).31, 34, 39 Antiepileptic drugs, such as phenytoin and carbamazepine, are used to control the seizures. Newer antiepileptic drugs may also be at least effective. Neurosurgery is the mainstay of therapy for obstructive hydrocephalus.40 Most cysticerci in the ventricles can be managed by endoscopic
Other larval cestode infections
Sparganosis refers to tissue infection with the larval (plerocercoid) stage of Spirometra mansonoides. Sparganosis is acquired from exposure of skin to infected flesh (eg, poultices of infected frogs, birds, or fish) or by ingestion. The plerocercoids develop in tissues, causing subcutaneous or central nervous system nodules or larva migrans. Treatment usually requires surgical removal of the nodule.48
Coenurosis is a rare infection caused by the human infection of Taenia serialis or Taenia
Acknowledgments
The authors are grateful to Prof Peter Kern, University of Ulm, Ulm, Germany, for reviewing the section on Alveolar echinococcosis and to Prof Hugo Garcia, Universidad Peruana Cayetano Heredia, Lima, Peru, for providing the CT and MRI images of neurocysticercosis.
References (49)
The taxonomy, phylogeny and transmission of Echinococcus
Exp Parasitol
(2008)- et al.
MR imaging for diagnosing cysto-biliary fistulas in cystic echinococcosis
Eur J Radiol
(2008) - et al.
Expert consensus for the diagnosis and treatment of cystic and alveolar echinococcosis in humans
Acta Trop
(2010) Hydatid cyst of the liver-criteria for the selection of appropriate treatment
Acta Trop
(2003)- et al.
Praziquantel: neglected drug? Ineffective treatment? Or therapeutic choice in cystic hydatid disease?
Acta Trop
(2009) - et al.
Percutaneous imaging-guided treatment of hydatid liver cysts: do long-term results make it a first choice?
Eur J Radiol
(2006) - et al.
Alveolar echinococcosis: from a deadly disease to a well-controlled infection. Relative survival and economic analysis in Switzerland over the last 35 years
J Hepatol
(2008) - et al.
Detecting spatial clusters of Taenia solium infections in a rural block in South India
Trans R Soc Trop Med Hyg
(2010) - et al.
Perilesional brain oedema and seizure activity in patients with calcified neurocysticercosis: a prospective cohort and nested case-control study
Lancet Neurol
(2008) - et al.
Sparganosis in mainland China
Int J Infect Dis
(2011)
Application of ultrasound in diagnosis, treatment, epidemiology, public health and control of Echinococcus granulosus and E. multilocularis
Parasitology
International classification of ultrasound images in cystic echinococcosis for application in clinical and field epidemiological settings
Acta Trop
Update on cystic hydatid disease
Curr Opin Infect Dis
Metabolic viability assessment of cystic echinococcosis using high-field (1)H MRS of cyst contents
NMR Biomed
Management of cystic echinococcosis complications and dissemination: where is the evidence?
World J Surg
Justified concern or exaggerated fear: the risk of anaphylaxis in percutaneous treatment of cystic echinococcosis-a systematic literature review
PLoS Negl Trop Dis
Efficacy and safety of PAIR for cystic echinococcosis: experience on a large series of patients from Bulgaria
Am J Trop Med Hyg
Treatment response of cystic echinococcosis to benzimidazoles: a systematic review
PLoS Negl Trop Dis
Cystic echinococcosis: chronic, complex, and still neglected
PLoS Negl Trop Dis
The global burden of alveolar echinococcosis
PLoS Negl Trop Dis
Echinococcus multilocularis in Europe–state of the art
Vet Res Commun
Biological, epidemiological, and clinical aspects of echinococcosis, a zoonosis of increasing concern
Clin Microbiol Rev
Should possible recurrence of disease contraindicate liver transplantation in patients with end-stage alveolar echinococcosis? A 20-year follow-up study
Liver Transpl
A systematic review of the frequency of neurocyticercosis with a focus on people with epilepsy
PLoS Negl Trop Dis
Cited by (0)
The authors declare no conflicts of interest.