Book contents
- Frontmatter
- Contents
- Introduction
- Participants
- Non-Participant Contributors
- Part 1 Transmissible diseases with long development times and vaccination strategies
- Part 2 Dynamics of immunity (development of disease within individuals)
- Part 3 Population heterogeneity (mixing)
- Part 4 Consequences of treatment interventions
- Conflicts between the individual and communities in treatment and control
- The design and analysis of HIV clinical trials
- A theory of population dynamics used for improving control of viral diseases: AZT chemotherapy and measles vaccination policy
- The ONCHOSIM model and it use in decision support for river blindness control
- Invited Discussion
- Invited Discussion
- Hydatid disease
- Vaccines and herd immunity: consequences for vaccine evaluation
- An epidemiological approach to the evaluation of disease control strategies for intestinal helminth infections: an age structured model
- The control of directly transmitted infections by pulse vaccination: concepts and preliminary studies
- Operational models for the prevention of blindness
- Part 5 Prediction
Hydatid disease
Published online by Cambridge University Press: 04 August 2010
- Frontmatter
- Contents
- Introduction
- Participants
- Non-Participant Contributors
- Part 1 Transmissible diseases with long development times and vaccination strategies
- Part 2 Dynamics of immunity (development of disease within individuals)
- Part 3 Population heterogeneity (mixing)
- Part 4 Consequences of treatment interventions
- Conflicts between the individual and communities in treatment and control
- The design and analysis of HIV clinical trials
- A theory of population dynamics used for improving control of viral diseases: AZT chemotherapy and measles vaccination policy
- The ONCHOSIM model and it use in decision support for river blindness control
- Invited Discussion
- Invited Discussion
- Hydatid disease
- Vaccines and herd immunity: consequences for vaccine evaluation
- An epidemiological approach to the evaluation of disease control strategies for intestinal helminth infections: an age structured model
- The control of directly transmitted infections by pulse vaccination: concepts and preliminary studies
- Operational models for the prevention of blindness
- Part 5 Prediction
Summary
Introduction
Hydatid disease is caused by accidental infection with the intermediate stages of tapeworms of Echinococcus species, principally Echinococcus granulosus and E.multilocularis. The adult worm parasitises the small intestine of carnivores, usually Canidae, and sheds proglottids containing eggs which pass with the host's faeces. If the eggs are then ingested by a herbivore they develop into a larval stage (cyst) within the liver or other viscera. The cycle is completed when the carnivore consumes the herbivore, ingesting a mature cyst. Echinococcus granulosus originated in a wolf-deer life-cycle, and has evolved in dogs and sheep and other domesticated and wild animals. The definitive hosts of E.multilocularis are foxes, and the intermediate hosts small rodents such as voles and lemmings. Echinococcus granulosus is ubiquitous but E.multilocularis is confined to the Northern Hemisphere. Cystic hydatid disease in man is caused by the larval form of E.granulosus. Surgery provides a cure in 50–90% of cases, but recurrence is common. Alveolar hydatid disease caused by E.multilocularis results in metastases throughout the soft organs. Until recently it was invariably fatal, but chemotherapy may retard the proliferation of cysts. For further information on the epidemiology of echinococcosis and hydatid disease see Roberts and Gemmell (1994). This paper presents two examples where models of the dynamics of Echinococcus species have been used to investigate control policies.
Echinococcus granulosusin farmed animals in New Zealand.
The first case of cystic hydatid disease in New Zealand was recorded in 1862. The annual number of cases peaked at 7.2 per 100,000 in 1946, and then declined to 0.37 per 100,000 in 1987, largely due to the control programme that was initiated in 1959. From that time all dogs were subjected to regular chemotherapy to remove tapeworms.
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- Information
- Models for Infectious Human DiseasesTheir Structure and Relation to Data, pp. 388 - 391Publisher: Cambridge University PressPrint publication year: 1996