Echinococcosis is an important medical, veterinary and economic concern in India. The public health and economic significance of echinococcosis as the most important of the cestode zoonoses, have resulted, particularly in the case of E. granulosus, in the widespread global perpetuation of Echinococcus in a variety of domestic, man-made life-cycle patterns (Eckert 1998; Schantz et al. 1995). Although the disease in domestic animals is usually asymptomatic and detected only at the time of post mortem inspection at the abattoir, it causes great economic loss through condemnation of infected offal, in particular liver. Surveys of prevalence of echinococcosis in livestock are important for comparing transmission levels quantitatively within and between regions, and for determining the significance of each species of animal in the transmission dynamics.

The recognition of strain variation is a major pre-requisite for strategic control efforts aimed at limiting transmission in an endemic area. A number of intraspecific variants or strains are known to occur within the species E. granulosus (Eckert and Thompson 1995). Variation in the pathogenicity of strains/species of Echinococcus will influence the prognosis in patients with echinococcosis. Gordo and Bandera (1997) demonstrated that morphological characteristics can also be used as a valid criterion for strain identification. Despite the strong evidence to show the endemicity of these serious zoonoses, documentation and surveillance data concerning to the prevalence and risk factors associated with zoonotic parasites in India is largely lacking. There is an urgent need for more recent parasite data to be obtained. In Indian scenario, the conditions for the establishment and transmission of hydatidosis in both livestock and humans are very ideal. The purpose of this study was to document the prevalence and to analyze morphological characteristics from hydatid cysts to test their suitability for strain identification.

Hydatid disease or Echinococcosis is a zoonotic disease caused by the larvae (metacestode) of the cestode species of the genus Echinococcus like E. granulosus, E. multilocularis, E. vogeli or E. oligarthus. Classical Cystic Echinococcosis (CE) is caused by E. granulosus complex, while E. multilocularis and E. vogeli are responsible for alveolar echinococcosis and polycystic echinococcosis, respectively. The study of E. granulosus species has revealed identification of substantial phenotypic and genetic variability and several strains. All identified strains utilize dogs and other canids as definitive hosts, but differ in the choice of intermediate host, geographic distribution, adult and metacestode morphology, maturation time in definitive hosts, organ localization of metacestode, and protoscolex production. At least, seven of nine E. granulosus genotypes are infective to humans. Globally, most human cases of CE are caused by the sheep strain (G1) of E. Granulosus. In India G1 and G5 (cattle strain) strain of E. granulosus have been frequently associated with CE. G2 genotype (Tasmanian sheep strain) in buffalo has been reported from India. Humans acquire primary CE by ingestion of E. granulosus eggs excreted by infected carnivores. The infection may be acquired by contact with infected definitive hosts, egg-containing feces, or egg-contaminated plants or soil followed by direct hand-to-mouth transfer. Dog ownership has not been found to be a risk factor in seropositive individuals, indicating an indirect contact with dog feces in the environment. Eggs can also be ingested with vegetables, salads, uncooked fruits, drinking water, and other plants that become contaminated.

Key facts

  • Human echinococcosis is a parasitic disease caused by tapeworms of the genus Echinococcus.
  • The two most important forms of the disease in humans are cystic echinococcosis (hydatidosis) and alveolar echinococcosis.
    Humans are infected through ingestion of parasite eggs in contaminated food, water or soil, or through direct contact with animal hosts.
  • Echinococcosis is often expensive and complicated to treat, and may require extensive surgery and/or prolonged drug therapy.
  • Prevention programmes focus on deworming of dogs and sheep, which are the definitive hosts. In the case of cystic echinococcosis, control measures also include improved food inspection, slaughterhouse hygiene, and public education campaigns. Vaccination of lambs is currently being evaluated as an additional intervention.
  • More than 1 million people are affected with echinococcosis at any one time.
  • WHO is working towards the validation of effective cystic echinococcosis control strategies by 2020.

Human echinococcosis is a zoonotic disease (a disease that is transmitted to humans from animals) that is caused by parasites, namely tapeworms of the genus Echinococcus. Echinococcosis occurs in 4 forms:

  • cystic echinococcosis, also known as hydatid disease or hydatidosis, caused by infection with Echinococcus granulosus;
  • alveolar echinococcosis, caused by infection with E. multilocularis;
  • polycystic echinococcosis, caused by infection with E. vogeli; and
  • unicystic echinococcosis, caused by infection with E. oligarthrus.

The two most important forms, which are of medical and public health relevance in humans, are cystic echinococcosis (CE) and alveolar echinococcosis (AE).


Video links

Echinococcosis Documentry

Echinococcosis, also called Hydatid Disease (Documentary)

Cystic Echinococcosis aka Hydatid Cyst of the Liver


Echinococcosis is a parasitic disease of tapeworms of the Echinococcus type. The two main types of the disease are cystic echinococcosis and alveolar echinococcosis.[1] Less common forms include polycystic echinococcosis and unicystic echinococcosis.
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