Elsevier

The Lancet

Volume 362, Issue 9392, 18 October 2003, Pages 1295-1304
The Lancet

Seminar
Echinococcosis

https://doi.org/10.1016/S0140-6736(03)14573-4Get rights and content

Summary

Echinococcosis is a near-cosmopolitan zoonosis caused by adult or larval stages of cestodes belonging to the genus Echinococcus (family Taenlldae). The two major species of medical and public health importance are Echinococcus granulosus and Echinococcus multilocularis, which cause cystic echinococcosis and alveolar echinococcosls, respectively. Both are serious and severe diseases, the latter especially so, with high fatality rates and poor prognosis if managed incorrectly. Several reports have shown that both diseases are of increasing public health concern and that both can be regarded as emerging or re-emerging diseases. In this review we discuss aspects of the biology, life cycle, aetiology, distribution, and transmission of the Echinococcus organisms, and the epidemiology, clinical features, treatment, and diagnosis of the diseases they cause. We also discuss the countermeasures available for the control and prevention of these diseases. E granulosus still has a wide geographical distribution, although effective control against cystic echinococcosis has been achieved in some regions. E multilocularis and alveolar echinococcosis are more problematic, since the primary transmission cycle is almost always sylvatic so that efficient and cost-effective methods for control are unavailable.

Section snippets

Distribution

E granulosus has a worldwide geographical distribution (figure 3). It is found on all continents, with highest prevalence in parts of Eurasia (especially Mediterranean countries, the Russian Federation and adjacent independent states, and China), north and east Africa, Australia, and South America.17 There is clear evidence for the emergence or re-emergence of human cystic echinococcosis in parts of China, central Asia, eastern Europe, and Israel.17, 18 Communities involved in sheep farming

Epidemiology and transmission

Exposure to Echinococcus eggs may be affected by occupational and behavioural factors. In the case of E multilocularis, hunters, trappers, and mushroom pickers would be expected to be more highly exposed than the general population, but there is little evidence that these groups are at increased risk of infection.25, 26, 27 The wide distribution and generally high frequency of E multilocularis in foxes is not reflected in rates of infection in man which, for reasons not fully understood, are

Clinical features

The initial phase of primary infection is always asymptomatic. Small cysts not inducing major disease may remain asymptomatic for many years, if not permanently. The incubation period of cystic echinococcosis is unclear but probably lasts for many months to years. The infection may become symptomatic if the cysts either rupture or exert a mass-effect. Recurrence may arise following surgery on primary cysts. Cystic echinococcosis has been reported to present for medical attention in people aged

Diagnosis

Early diagnosis of cystic and alveolar echinococcosis can provide substantial improvements in the quality of the management and treatment of both diseases. In most cases, the early stages of infection are asymptomatic, so methods that are cheap and quite easy to use are needed for large-scale screening of populations at high risk. The definitive diagnosis for most cases of cystic and alveolar echinococcosis in man is by physical imaging methods, such as radiology, ultrasonography, computed

Treatment of cystic echinococcosis

Asymptomatic hepatic cystic echinococcosis is common in endemic regions and up to 75% of infected people may remain symptom free for more than 10 years.80 Cysts may be seen to expand, become septate, or calcify when patients are monitored with serial ultrasound. Community studies with screening ultrasound have identified an increased frequency of this condition compared to similar studies of patients presenting for medical attention.81 Treatment should be reserved for symptomatic lesions or

PAIR

The Puncture, Aspiration, Injection, Reaspiration (PAIR) technique was introduced in the mid-1980s.83, 84 The cyst is punctured under ultrasound guidance, as much cyst fluid is aspirated as possible, a protoscolicide (eg, 95% ethanol) is injected, and cyst contents are reaspirated 15-20 min later. Only skilled practitioners should undertake this technique, with intensive-care support in the event of anaphylaxis. Cyst aspirates should be assessed for the presence of protoscolices and bilirubin.

Treatment of alveolar echinococcosis

Radical surgery—as for hepatic malignancy—has been the historical cornerstone of treatment for alveolar echinococcosis.59 Early diagnosis is crucial, and results in a reduced rate of unresectable lesions and reduces the need for radical surgery.100 Perioperative and long-term adjuvant chemotherapy with albendazole (doses up to 20 mg/kg per day) has been associated with 10-year survival of approximately 80%, compared with less than 25% in historical controls.42, 101 Albendazole is only

Prevention and control

Preventive measures that have been used to control Echinococcus infections include avoidance of contact with dog or fox faeces, handwashing and improved sanitation, reducing dog or fox populations, treatment of dogs with arecoline hydrobromide or praziquantel or use of praziquantel-impregnated baits, incineration of infected organs, and health education. Despite ongoing control efforts, few countries have been able to substantially reduce or eradicate alveolar or cystic echinococcosis. However,

Conclusions

Despite the establishment of extensive and successful control programmes in some countries or regions, E granulosus still has a very wide geographic distribution. Worryingly, recent evidence points to cystic echinococcosis being a public health problem of increasing concern in a number of countries where control programmes have been reduced due to economic problems and lack of resources, or have yet to be fully instigated.21 It is likely that, unless government health authorities prioritise the

References (113)

  • A Ito

    Serologic and molecular diagnosis of zoonotic larval cestode infections

    Parasitol Int

    (2002)
  • L Ma et al.

    Alveolar echinococcosis: Em2plus-ELISA and Em18-western blots for follow-up after treatment with albendazole

    Trans R Soc Trop Med Hyg

    (1997)
  • A Ito et al.

    Development of an Em18 immunoblot and Em18-ELISA for specific diagnosis of alveolar echinococcosis

    Acta Trop

    (2003)
  • W Yong et al.

    Comparison of cestode antigens in an enzyme-linked immunosorbent assay for the diagnosis of Echinococcus granulosus, Taenia hydatigena and Taenia ovis infections in sheep

    Res Vet Sci

    (1984)
  • R Kittelberger et al.

    Evaluation of three enzyme-linked immunosorbent assays (ELISAs) for the detection of serum antibodies in sheep infected with

    Echinococcus granulosus. Vet Parasitol

    (2002)
  • P Craig et al.

    Immunodetection of Echinococcus eggs from naturally infected dogs and from environmental contamination sites in settlements in Turkana, Kenya

    Trans R Soc Trop Med Hyg

    (1988)
  • R Gasser et al.

    Echinococcus granulosus: antigenic proteins in oncospheres and on the surface of protoscoleces identified by serum antibodies from infected dogs

    Res Vet Sci

    (1991)
  • M Cabrera et al.

    Identification of Echinococcus granulosus eggs

    Diagn Microbiol Infect Dis

    (2002)
  • B Frider et al.

    Long-term outcome of asymptomatic liver hydatidosis

    J Hepatol

    (1999)
  • C Filice et al.

    Use of PAIR in human cystic echinococcosis

    Acta Trop

    (1997)
  • V Pelaez et al.

    PAIR as percutaneous treatment of hydatid liver cysts

    Acta Trop

    (2000)
  • R Horton

    Albendazole in treatment of human cystic echinococcosis: 12 years of experience

    Acta Trop

    (1997)
  • L Gil-Grande et al.

    Randomised controlled trial of efficacy of albendazole in intra-abdominal hydatid disease

    Lancet

    (1993)
  • R Rausch et al.

    The epidemiology of echinococcosis caused by Echinococcus oligarthrus and E vogeli in the neotropics

  • A D'Alesandro

    Polycystic echinococcosis in tropical America: Echinococcus vogeli and

    E oligarthrus. Acta Trop

    (1997)
  • RCA Thompson et al.

    Aetiology: parasites and life-cycles

  • J Eckert et al.

    Echinococcosis in animals: clinical aspects, diagnosis and treatment

  • CNL Macpherson

    An active intermediate host role for man in the life cycle of Echinococcus granulosus in Turkana, Kenya

    Am J Trop Med Parasitol

    (1983)
  • DP McManus et al.

    Biochemistry, physiology and molecular biology of Echinococcus.

  • KL Haag et al.

    Reduced genetic variability within coding and non-coding regions of the Echinococcus multiolocularis genome

    Parasitology

    (1997)
  • H Rinder et al.

    Limited range of genetic variation in

    Echinococcus multilocularis. J Parasitol

    (1997)
  • J Bowles et al.

    A molecular phylogeny of the genus

    Echinococcus. Parasitology

    (1995)
  • RCA Thompson

    Biology and systematics of Echinococcus.

  • T Le et al.

    Complete mitochondrial genomes confirm the distinctiveness of the horse-dog and sheep-dog strains of

    Echinococcus granulosus. Parasitology

    (2002)
  • J Eckert et al.

    Geographic distribution and prevalence

  • L Castrodale et al.

    Two atypical cases of cystic echinococcosis (Echinococcus granulosus) in Alaska

    Am J Trop Med Hyg

    (1999)
  • DP McManus et al.

    Short report: molecular genetic characterization of an unusually severe case of hydatid disease in Alaska caused by the cervid strain of

    Echinococcus granulosus. Am J Trop Med Hyg

    (2002)
  • G Bartholomot et al.

    Combined ultrasound and serologic screening for hepatic alveolar echinococcosis in central China

    Am J Trop Med Hyg

    (2002)
  • T Sreter et al.

    Echinosossus multilocularis: an emerging pathogen in Hungary and central Eastern Europe?

    Emerg Infect Dis

    (2003)
  • R Doi et al.

    Epidemiology of multilocular echinococcosis in Hokkaido. (1) A sero-epidemiological study of hunters

    Jap J Pub Health

    (1987)
  • J Eckert et al.

    Epidemiology of Echinococcus multilocularis, Echinococcus vogeli and Echinococcus oligarthrus.

  • M Hildreth et al.

    Failure to identify alveolar echinococcosis in trappers from South Dakota in spite of high prevalence of Echinococcus multilocularis in wild canids.

    J Parasitol

    (2000)
  • B Gottstein et al.

    Is high prevalence of Echinococcus multilocularis in wild and domestic animals associated with disease incidence in humans?

    Emerg Infect Dis

    (2001)
  • B Gottstein et al.

    Association between HLA-DR13 and susceptibility to alveolar echinococcosis

    J Infect Dis

    (1994)
  • V Godot et al.

    Resistance/susceptibility to Echinococcus multilocularis infection and cytokine profile in humans. II. Influence of the HLA B8, DR3, DQ2 haplotype

    Clin Exp Immunol

    (2000)
  • T Eiermann et al.

    HLA and alveolar echinococcosis

    Tissue Antigens

    (1998)
  • S Zhang et al.

    Polymorphisms of the TAP1 and TAP2 genes in human alveolar echinococcosis

    Eur J Immunogenet

    (2003)
  • M Gemmel et al.

    Modelling Echinococcus life cycles

  • P Torgerson

    Transmission dynamics of taeniid parasites in anaimal hosts

  • P Giraudoux et al.

    Transmission ecology of Echinococcus multilocularis in wildlife: what can be learned from comparative studies and multicscale approaches?

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