Wilderness in the city: the urbanization of Echinococcus multilocularis

doi:10.1016/j.pt.2003.11.011

Trends in Parasitology

Volume 20, Issue 2, February 2004, Pages 77-84

https://doi.org/10.1016/j.pt.2003.11.011 Get rights and content

Abstract

A distinct increase in fox populations, particularly in urban areas, has been observed in Europe. This is of particular concern in endemic regions of the small fox tapeworm Echinococcus multilocularis, the aetiological agent of human alveolar echinococcosis. Novel tools have facilitated the investigation of the ecology of urban foxes and have demonstrated the urban wildlife cycle of E. multilocularis. Such studies are essential for estimating the risk of transmission to humans and to determine the basics for the development of control strategies.

Section snippets

The urban fox phenomenon

Red foxes living in urban areas have been known in Britain since the 1930s [12]. In the 1970s and 1980s, urban fox densities of up to five family groups per km² were recorded. Because these observations were unique, urban foxes were initially thought to be an isolated British phenomenon 13, 14.

In the 1970s and 1980s, continental fox populations suffered heavily from a rabies epizootic, a zoonosis not present in the UK. Subsequently, fox populations decreased drastically. However, fox

Echinococcus multilocularis in urban settings

In the past five years, the occurrence of E. multilocularis in urban foxes has been reported from several European cities (e.g. Copenhagen [29], Geneva [30], Stuttgart [7] and Zürich [31]). To date, the urban transmission of E. multilocularis has been most comprehensively documented in Zürich. Over a period of 26 months (1996–1998), foxes were examined for intestinal infections with E. multilocularis and other helminths (Table 1). Seasonal differences in the prevalence of E. multilocularis were

Echinococcus multilocularis infection in domestic carnivores

The presence of an urban wildlife cycle of E. multilocularis is now documented in several European cities. Hence, there is an increasing risk of infection with E. multilocularis for domestic dogs and cats by preying on metacestode-infected rodents. Both dogs and cats can reach extremely high population densities in urban areas. According to the Zürich dog tax statistics, there are 0.7 dogs per ha and the cat population is estimated to be around three times higher. In Brooklyn, New York,

Options on control of AE in urban areas

The high prevalence of E. multilocularis in growing urban fox populations, the environmental contamination with eggs and the emerging public awareness concerning urban zoonoses could justify implementation of control strategies in the future. Apart from ongoing, carefully planned information campaigns about this zoonosis and its potential risks [45], research on possible control strategies is of major interest.

A reduction in the abundance of intermediate rodent hosts is very difficult and

Conclusions

On the basis of the high prevalence of E. multilocularis in the growing fox populations, the total biomass has probably increased significantly in the past 20 years in central Europe. As illustrated in Figure 5, various factors determine the degree of E. multilocularis egg contamination, which reaches a maximum in villages and urban peripheries where rural and urban habitats intersect. Because the public intensively uses these areas, they could play an important role for transmission of human

Acknowledgements

We acknowledge the support of our research activities by the Swiss National Science Foundation (grant no. 31–47031.96), the Swiss Federal Office of Veterinary Medicine, Berne, the Swiss Federal Office for Education and Science (EU FAIR Projekt CT97–3515/BBW Nr. 97.0586), and the European Commission (Project Echinorisk, Contract QLK2-CT-2001–01995). We are grateful to Andreas König, Dorothea Thoma and Claude Fischer for the provision of unpublished observations.

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Trends in Parasitology

Wilderness in the city: the urbanization of Echinococcus multilocularis

Abstract

Section snippets

The urban fox phenomenon

Echinococcus multilocularis in urban settings

Echinococcus multilocularis infection in domestic carnivores

Options on control of AE in urban areas

Conclusions

Acknowledgements

Parasitol. Today

Acta Trop.

Anim. Behav.

Int. J. Parasitol.

Int. J. Parasitol.

Vet. Parasitol.

Vet. Parasitol.

Vet. Parasitol.

Life cycles of Echinococcus multilocularis in relation to human infection

J. Parasitol.

Epidemiology and control of hydatid disease

Geographic distribution and prevalence

Echinococcus multilocularis in animal hosts: new data from western Europe

Helminthologia

Echinococcus multilocularis: an emerging pathogen in Hungary and Central Eastern Europe?

Emerg. Infect. Dis.

Role of rabies in recent demographic changes in red fox (Vulpes vulpes) populations in Europe

Mammalia

The final phase of the rabies epizootic in Switzerland

Schweiz. Arch. Tierheilkd.

The rise of urban fox populations in Switzerland

Mamm. Biol.

A discriminant analysis of the current distribution of urban foxes (Vulpes vulpes) in Britain

J. Anim. Ecol.

Distribution, habitat utilization and age structure of a suburban fox (Vulpes vulpes) population

Mamm. Rev.

The distribution and ecology of foxes, Vulpes vulpes (L.), in urban areas

Reproductive-performance of the red fox, Vulpes vulpes, in Garmisch-Partenkirchen, Germany, 1987–1992

Mamm. Biol.

Oral immunization of wildlife against rabies: concept and first field experiments

Rev. Infect. Dis.

Urban fox population in Oslo

Revue d'Ecologie

The food of rural and suburban woodland foxes Vulpes vulpes in Denmark

Nat. Jutl.

Home ranges, movements and habitat associations of red foxes Vulpes vulpes in suburban Toronto, Ontario, Canada

Can. J. Zool.

Preliminary study of the role of red foxes in Echinococcus multilocularis transmission in the urban area of Sapporo, Japan

Parasitology

Drifting territoriality in the red fox Vulpes vulpes

J. Anim. Ecol.

Dispersal distance, home-range size and population density in the red fox (Vulpes vulpes): a quantitative analysis

J. Appl. Ecol.

Comparison of heavy metal concentrations in tissues of red foxes from adjacent urban, suburban, and rural areas

Arch. Environ. Contam. Toxicol.