Echinococcosis is one of the world's most geographically widespread parasitic zoonoses, with transmission occurring in tropical, temperate and arctic biomes. Most human infections are due to Echinococcus granulosus transmitted between domestic dogs and livestock, but this cosmopolitan species also cycles between wild carnivores (principally canids) and wild ungulates. The other species with significant zoonotic potential is E. multilocularis that occurs naturally in fox definitive hosts and small mammal intermediate hosts. These two species cause human cystic or alveolar echinococcosis respectively, which may be considered serious public health problems in several regions including developed countries. This review provides an introductory overview to the Supplement and summarises the biology and epidemiology of these two related cestodes with an emphasis on applied aspects relating to detection, diagnosis and surveillance in animal and human populations, and includes aspects of transmission ecology, and also considers aspects of community epidemiology and potential for control.
TWO SPECIES OF ECHINOCOCCUS OCCUR IN CANADA: (1) E. multilocularis and (2) E. granulosus. E. multilocularis, originating in the Arctic, is spreading southwards and has reached Saskatchewan and the Dakotas. The original hosts are foxes but dogs and cats are alternatives. The larvae occur in field mice as multilocular microcysts containing numerous protoscolices, but in man the cysts are alveolar and sterile and resemble both in histology and growth a cholangiocellular carcinoma of the liver with metastases. Signs and symptoms are chronic and poorly defined. Diagnosis is difficult. Test antigens are not yet satisfactory. E. granulosus has a sylvatic cycle, the adult tapeworms living in wolves and dogs, while the larvae occur only in Cervidae and man. The cysts occur almost exclusively in the lungs as unilocular, macrocystic, relatively benign tumours, although abnormal complications can occur. The Casoni intradermal sensitivity test, its technique and interpretation are discussed.
With the increased influx of foreign workers, refugees and immigrants, particularly from endemic areas, we will probably see more patients with hydatid disease, chiefly hydatid disease of the liver caused by E. granulosus. Thus it is important to bring the disease to the attention of the general surgeon. The diagnosis of hydatid disease is primarily made by ultrasound and serological examination. Other tests such as CT, angiography and ERCP are as a rule only important in surgical planning and in complicated cases. Treatment is principally surgical. The choice of surgical procedure should be individualized as much as possible due to the many aspects of the disease. Drainage of residual cavities should be avoided. Preoperative evaluation by ERCP is indicated in cases complicated by biliary communication. Percutaneous drainage can be indicated in cases of recurrence and in cysts of poor accessability. Medical treatment has its place primarily pre- and postoperatively. The preferred drug is albendazole. Mebendazole is now considered obsolete. It is not possible to monitor the effect of treatment with current serological methods.
Echinococcus multilocularis is a parasite that can cause alveolar echinococcosis disease. After the first positive finding of E. multilocularis in Sweden in 2011, a consulting group with representatives from relevant authorities was summoned. In this group, all relevant information was shared, strategies for information dissemination and any actions to be taken due to the finding of E. multilocularis were discussed and decided. The present paper describes the actions taken during 2011 and the results thereof, including surveillance in animals, risk assessment for humans to become infected and recommendations given to the public. Further discussion about whether the parasite was introduced, and if so, how, as well as possible future development of the infection in animals and humans in Sweden and future actions are included.
Mitochondrial haplotypes were determined for Echinococcus species infecting individuals diagnosed with alveolar echinococcosis (AE) and cystic echinococcosis (CE) at Altai State Medical University Hospital in Barnaul, Russia during 2008 to 2011. The nucleotide sequence of the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene was determined for 31 of 34 AE and 8 of 12 CE cases. All of the AE cases were confirmed to be caused by Asian type Echinococcus multilocularis, while CE cases were caused by Echinococcus granulosus sensu stricto (genotype G1) and Echinococcus canadensis (genotype G6).
Complex of measures for prophylaxis of echinococcosis recurrence was developed basing on experimental and clinical studies. Results of surgical treatment of echinococcosis of different location in 983 patients were analyzed. Complex approach to the treatment reduced the rate of recurrences to 0.6% (p=0,0002). Criteria of recovery and algorithm of early diagnosis of echinococcosis recurrence are presented.