Hydatid disease transmission in California. A study of the Basque connection

A descriptive epidemiologic and anthropologic study was designed to determine by field observation and interview the extent of Basque involvement in the sheep industry of California, the nature of the sheep and dog husbandry practices of California Basques as they might influence Echinococus granulosus transmission, and the "folk knowledge" of hydatid disease possessed by California Basques, particularly as it might indicate the early presence of this infection in California and provide evidence for or against possible intensification or spread of transmission in the recent past. Basques were found to dominate the sheep industry of California's Central Valley from Sacramento south, but to be virtually absent from other sheep-raising areas of the state. In contrast to most other California sheep ranchers, Basques practice a transhumant form of husbandry in which bands of sheep are moved from location to location under the control of contract Basque shepherds from Spain and France and a number of sheep dogs.

Sylvatic echinococcosis in Argentina. I. On the morphology and biology of strobilar Echinococcus granulosus (Batsch, 1786) from domestic and sylvatic animal hosts

Dogs were fed larvae of Echinococcus granulosus (Batsch, 1786) recovered from sheep in Argentina. The morphological characteristics of strobilae recovered from dogs at 28, 60 and 76 days postexposure were compared with those of Echinococcus spp. recovered from naturally infected foxes, Dusicyon clupaeus (Molina) and D. griseus (Gray), and those of worms reared in dogs from larvae in European hares, Lepus europaeus (L.). Only slight differences were observed in characters of taxonomic importance and it was concluded that all cestodes represented a single species, E. granulosus. The results are discussed as they bear on the speciation controversy and the potential epidemiology importance of Dusicyon spp. as hosts of E. granulosus. It was suggested that E. patagonicus Szidat, 1960 previously described from D. culpaeus is conspecific with E. granulosus. E. cepanzoi Szidat, 1971 is probably also a synonym of E. granulosus and the subspecies E. g. dusicyontis Blood and Lelijveld, 1969, is rejected on the grounds that there is no evidence for host specificity and ecological or other segregation from the nominate form. Foxes appear to become infected from scavenging on dead sheep in localities where E. granulosus is endemic in domestic animals. There is still no evidence that E. granulosus is maintained in Argentina in sylvatic cycles.

The role of the marabou stork (Leptoptilos crumeniferus (Lesson)) in Kenya in the spread of echinococcosis from the abattoir

In experiments, adult marabou storks were fed with hydatid fluid of viable Echinococcus cysts obtained from sheep and goats. On microscopic examination of the birds' faeces no scolices were found, the only remaining undigested parts of the parasites fed being the chitinous hooks of the rostellum. The feeding trials have shown that the marabou does not play a role in the spread of echinococcosis from the abattoir.

The fox as a definitive host of Echinococcus and its role in the spread of hydatid disease

In the first part of this discussion of the significance of the fox in the epidemiology of hydatid disease in man, the author reviews the literature on vulpine echinococciasis. He points out that the evidence available from field surveys and laboratory observations suggests that the fox is not a definitive host of Echinococcus granulosus-the parasite responsible for the most common form of hydatid disease in man-but is a host of E. multilocularis, which is found in parts of Europe and Asia, in the islands of the Bering Sea and in Alaska, and is known to be the causal agent of alveolar hydatid disease.In the second part, the author presents the results of experimental infestation of the European red fox (Vulpes vulpes) with the Australian strain of E. granulosus. These results indicate that a few tapeworms became established in some of the foxes, but were retarded in growth (as compared with their growth in the dogs used as controls) and failed to reach sexual maturity (production of ova) even 112 days after infestation. The author therefore concludes that the fox plays no role in the spread of hydatid disease caused by E. granulosus in Australia.Finally, the author discusses the etiology of two autochthonous cases of alleged alveolar hydatid disease in man in Australasia, putting forward two alternative hypotheses to explain their occurrence.