Trends in Parasitology
Volume 33, Issue 10, October 2017, Pages 813-825
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Review
Zoonotic Parasites of Sheltered and Stray Dogs in the Era of the Global Economic and Political Crisis

https://doi.org/10.1016/j.pt.2017.05.013Get rights and content

Trends

Sheltered and stray dogs represent reservoirs of zoonotic parasites worldwide, especially in the context of the current global changes and economic crisis.

Stray dog populations are an underestimated problem in several countries, and management policies are virtually nonexistent, or not applied, particularly in developing nations.

Relocation of stray dogs from southern to northern countries of Europe has contributed to the establishment of parasites and/or their vectors in previously nonendemic areas.

Poverty and low public health standards may further worsen the welfare of dogs in developing and industrialized countries.

Sheltered and stray dogs, exposed to zoonotic parasites, including protozoa, helminths, and arthropods, may represent a major threat to public health. Resources for addressing health problems in these animals are not on the priority list of veterinary and public health authorities. Thus, dogs continue to represent an important reservoir for zoonotic parasites. In this article, we review the importance of sheltered and stray dogs as reservoirs of zoonotic parasites in different parts of the world, especially in the context of the current global political and economic crisis.

Section snippets

Zoonotic Parasites of Dogs

Dogs can carry a large number of parasites, such as protozoa (e.g., Babesia spp., Hepatozoon spp., and Leishmania spp.), helminths (e.g., roundworms, hookworms, whipworms, and tapeworms), and arthropods (e.g., mites, ticks, fleas, and lice). These parasites have successfully evolved to inhabit different organ systems of these hosts, and the outcome of such infection may range from subclinical to life-threatening disease. Many parasites of dogs are specific to canids and rarely infect other

Sheltered and Stray Dogs: The Tip of the Iceberg

The global population of domestic dogs is estimated at 703.3 million [16]. This number is growing fast. A total of 361 million dogs are estimated to live in Asia, 102.2 million in Latin America and the Caribbean, 87.6 million in Africa, 74.3 million in Europe, and 72.6 million in North America [16]. The USA alone has an estimated dog population of 66.8 million [16], and India an estimated population of 118 million [17]. However, these figures are likely underestimated as there is no reliable

Sheltered and Stray Dogs as Reservoirs of Zoonotic Parasites

The risk of parasitic infections in dogs depends on an array of biotic and abiotic factors, which vary according to each parasite’s biological life cycle as well as behavioural habits, management, and housing conditions of individual dogs (Figure 2). Furthermore, the risk is also determined by the owner’s attitude regarding the use of preventive strategies (e.g., prompt removal of faeces and the administration of preventive drugs). In the particular case of sheltered and stray dogs, the risk of

Burden of Zoonotic Parasites of Dogs Intricately Linked to Poverty

The gross domestic product (GDP) per capita is inversely linked to the percentage of stray or semi-domesticated dogs (Figure 3). Furthermore, the burden of zoonotic parasites of dogs is linked to poverty, but in some instances there are no reliable, updated estimates for the global and regional burden of these diseases. Examples of dog-associated parasites that disproportionately affect the poor include toxocariasis, cystic echinococcosis, and zoonotic visceral leishmaniasis. For instance,

Zoonotic Parasites of Dogs in the Southern vs. Northern Hemispheres

Zoonotic parasites accompany dogs, whether strays, sheltered, hunting, or pets, everywhere in the world, with polyparasitism being the rule, not the exception. Nonetheless, there are differences regarding the diversity and, in some instances, the burden of parasitic infections in dogs in the different geographical regions according to their climate, environment, and socioeconomic conditions which may favour or disfavour the presence and prevalence of certain parasite species. The USA and

Dog Population Control: Parasites and Management Policies

From a global perspective, management policies concerning stray and sheltered dogs vary widely and are virtually absent in several countries. Taking the European Union (EU) as an example, the welfare and management of stray animal populations remain under the responsibility of each member state, which is expected to develop and implement appropriate training programs to harmonise dog capture, transport, and holding practices as well as minimum housing and care criteria. Under the above

Relocation of Sheltered Dogs: Risk for New Parasites

The adoption of sheltered dogs and their relocation to other regions, and even other countries, may facilitate the introduction of zoonotic parasites into new areas. In Europe, for example, dog movements are governed by the EC Regulation No. 998/2003 of the European Parliament and of the Council of 26 May 2003 and amending Council Directive 92/65/EEC, which lays down the animal health requirements applicable to the noncommercial movement of pet animals. Other local regulations also apply, from

Concluding Remarks

Stray dogs are highly exposed to a range of zoonotic parasites (Table 1) and may become important reservoirs for human infection, particularly in poor urban and rural settings (see Outstanding Questions). Many sheltered dogs are dogs that were abandoned by their owners, but a large proportion of them used to be dogs that were born in the streets and grew up unsupervised, with little or no human dependence. As discussed throughout this review, stray and sheltered dog populations are a known, yet

Acknowledgments

The authors wish to thank Matteo Cornaggia for preparing Figure 2, and Alessio Giannelli for his assistance in formatting the manuscript.

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    These authors contributed equally to the writing of this manuscript.

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