title: Strain differences in Echinococcus granulosus, with special reference to the status of equine hydatidosis in the United Kingdom.
abstract: The genetics of speciation in the genus Echinococcus are briefly discussed. As the organism is a hermaphrodite and multiplies asexually in the larval stage, the genetic mechanism for the ready production of new strains is inherent in the life-cycle. Some biological, biochemical and nutritional differences between the horse and sheep strains are examined. The sheep strain may be grown to sexual maturity, in vitro, in a diphasic system; the horse strain fails to grow in such a system. Differences have also been demonstrated between the soluble proteins of the two strains. The sheep strain is infective to man but, probably, non-infective to horses. The horse strain (which is now the major strain in the U.K and Ireland) appears to be poorly infective to sheep and may prove to be non-infective to man. The importance of determining the basic characteristics of other strains of E. granulosus are also stressed.
mesh_terms: D000818:Animals; D012734:Disorders of Sex Development; D004283:Dog Diseases / Q000453:epidemiology; D004285:Dogs; D004443:Echinococcosis / Q000662:veterinary*; D004446:Echinococcus / Q000145:classification* / Q000254:growth & development; D006734:Horse Diseases / Q000453:epidemiology*; D006736:Horses; D006801:Humans; D012756:Sheep; D012757:Sheep Diseases / Q000453:epidemiology; D013045:Species Specificity; D006113:United Kingdom; D015047:Zoonoses / Q000453:epidemiology