Epidemiology in Small Animal Parasitology

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Epidemiology IN Small Animal Parasitology. Climate Change and Social, Economic and Political Factors

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Epidemiology

IN Small Animal Parasitology

Climate Change and Social, Economic and Political Factors Peter Holdsworth AO Maggie Fisher

Foreword by

Domenico Otranto

Epidemiology in Small Animal Parasitology

Climate Change and Social, Economic and Political Factors

€50.00

Epidemiology IN Small Animal Parasitology. Climate Change and Social, Economic and Political Factors

This book provides an understanding of climate change and other contributing factors in the emergence/reemergence of companion animal parasites. It describes the known changes in the epidemiology of key parasites and highlights zoonotic threats, and is therefore a valuable resource for veterinary practitioners to manage risks and keep abreast of emerging/reemerging parasitic diseases of pets.

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Epidemiology

IN Small Animal Parasitology

Climate Change and Social, Economic and Political Factors Peter Holdsworth AO Maggie Fisher

Foreword by

Domenico Otranto

£43.99

PY093199_Epidemiology_cover_SERVET.indd Todas las páginas

This book provides an understanding of climate change and other contributing factors in the emergence/reemergence of parasitic diseases in companion animal. It describes the known changes in the epidemiology of key parasite infections and highlights zoonotic threats, and is therefore a valuable resource for veterinary practitioners to manage risks and keep abreast of emerging/reemerging parasitic diseases of pets.

23/1/20 8:33

TARGET AUDIENCE:

✱ Small animal vets. Parasitology ✱ Veterinary students ✱ Veterinary nurses FORMAT: 17 × 24 cm NUMBER OF PAGES: 112 NUMBER OF IMAGES: 70 BINDING: hardcover ISBN: 978-84-18020-15-5

Authors PETER HOLDSWORTH Independent consultant. PhD in veterinary parasitology from the University of Queensland (Australia). Former president of the Australian Society for Parasitology (2008-2009) and the World Association for the Advancement of Veterinary Parasitology (WAAVP) (2011–2015).

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MAGGIE FISHER Graduate of the Royal Veterinary College (RVC) and diplomate of the European Veterinary Parasitology College. Former lecturer in veterinary parasitology at the RVC and Nottingham University. Professional director, business owner and consultant within the global veterinary parasitology arena.

KEY FEATURES:

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Written by renowned specialists in parasitology.

Provides many examples of the influence played by climate change and other factors in the epidemiology of small animal parasite infections.

Highlights zoonotic threats.

Presentation of the book Veterinary practitioners are the sentinels for veterinary disease incursions within our communities. Exotic animal parasites in general and zoonoses in particular pose a hazard to modern communities, and a One Health approach to risk management is therefore fundamental. This book provides an understanding of climate change and other contributing factors in the emergence/re-emergence of companion animal parasites. It describes the known changes in the epidemiology of key parasites and highlights zoonotic threats. It is a valuable resource for veterinary practitioners and clinic staff to manage risks and keep abreast of emerging/re-emerging parasitic diseases of pets.

This century has seen episodes of social upheaval and new dynamics of human displacement. Influxes of refugees, their pets, and accompanying infections, to the European Union and other regions challenge governments and their infrastructures. In addition, the recent unprecedented legitimate movements of people, their animals (and their parasites) around the world, has led to the introduction and mixing of genes, cultural preferences, customs, and behavioural patterns. Traditional government immigration and customs, quarantine and public health infrastructures are stretched in some regions and have been modified or have collapsed in others. Risk of incursions of infections has never been more critical.

The legal and societal expectations placed on veterinarians to manage this situation will increase. As such, veterinarians must be able to properly diagnose and treat of emerging/ re-emerging companion animal parasite infections and advise their clients on this issue.

Additionally, health and safety obligations require development and implementations of awareness programmes for veterinary practice staff.

Epidemiology in Small Animal Parasitology

The authors Peter Holdsworth Peter Holdsworth is an independent consultant to the global animal health industry. He holds a PhD in veterinary parasitology from the University of Queensland (Australia) and has published over 60 peer-reviewed scientific papers, reports, books and book chapters.

Peter is a fellow of the British Royal Society of Biology and of the Australian Institute of Company Directors.

Peter was president of the Australian Society for Parasitology (2008-2009) and the World Association for the Advancement of Veterinary Parasitology (WAAVP) (2011–2015) as well as a board member of the International Federation for Animal Health (2005–2013). He was also a member of the VICH (Veterinary International Conference on Harmonization) Steering Committee and of their veterinary anthelmintic testing guidelines working group (1998–2013). He was a member of the Australian delegation to the Codex Committee on Residues of Veterinary Drugs in Foods (1998–2013) and of the Ad hoc Codex Intergovernmental Task Force on Antimicrobial Resistance, where his work focused on establishing risk management procedures for dealing with antimicrobial resistance in relation to the use of veterinary antimicrobials (2005–2008).

Maggie Fisher Maggie Fisher is a graduate of the Royal Veterinary College (RVC, London, United Kingdom). She also holds a BVetMed from the University of London, is a diplomate of the European Veterinary Parasitology College and fellow of the British Royal Society of Biology. She has lectured in veterinary parasitology at the RVC and Nottingham University and in equine science at Hartpury College. Maggie is now a professional director, business owner and consultant within the global veterinary parasitology arena.

Maggie was an instigator (2006) and inaugural director of the European Scientific Council Companion Animal Parasites (2008–2014). She is at present an executive committee member of the World Association for the Advancement of Veterinary Parasitology (WAAVP) along with the chair of the WAAVP guideline sub-committee. She is member of the Association of Veterinary Consultants and now owns and directs the hands-on operation of three United Kingdom registered businesses: Shernacre Enterprise Limited (SEL), a platform to deliver independent consultancy and clinical research in veterinary parasitology; Ridgeway Research Limited (RRL), a contract research organisation; and Veterinary Research Limited (VRM), a specialist veterinary research management company.

Table of contents 1. Introduction 2. Epidemiology: an overview of its influencers and its investigation Quality of data Disease occurrence and determinants Transmission and maintenance of infection Climate change and disease ecology Risk and its prediction and mitigation Monitoring the effect of change and treatment Effect of treatment and prevention on the establishment of infection and disease

Walls and gardens providing sandfly habitats Asian tiger mosquito EU incursion caused by goods movement

7. Government and nonprofit programmes to tackle animal movement and parasite spread Quarantine approaches EU Pet Travel Scheme Exportation initiatives to deal with stray pets Legislative control of alien species The role of nonprofit organisations

3. climate change: predictions and known 8. Future approaches for monitoring and control effects on parasite populations

Establishing and managing priorities

Predictions Ectoparasites Gastrointestinal nematodes Vector-borne parasites

Known climate-related changes in parasite populations Ticks Vector-borne infections

4. Impact of animal movement and climate change Leishmaniosis Spread in Europe Spread in the USA International spread with transport of military dogs

Echinococcus multilocularis spread in Europe since rabies elimination Lyme borreliosis and the impact of Siberian chipmunk introduction into Europe Baylisascaris in Germany and the impact of Raccoon introduction

5. Impact of social, political and economic upheaval on the epidemiology of parasitic diseases Central Asian countries and the Soviet Union collapse Syrian military and civil conflict Greek financial crisis

6. Impacts of landscape, human dwellings and goods movement on parasite epidemiology Parasites in the interaction between wildlife, pets and humans in urban and suburban areas Influence of landscape on tick populations and Borrelia burgdoferi sensu lato prevalence

Editorial Servet

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Surveillance and monitoring: information gathering Establishing priorities Risk assessment and management Research

Managing prioritised risks Dissemination of information and education Prevention and control

9. Considerations for veterinarians Training Prevention of exotic infections Education of pet owners

Response to presentation of exotic infections Identification Availability of treatments Prevention of spread of the infection

Strategic planning Influencing public policy

10. Political/legal and societal measures for monitoring and control Being informed: Dissemination of information and education Communication Evaluating priorities and risk management Governmental controls Dog and cat population control Health governance Movement of parasites or vectors with movement of animals or goods Disaster preparedness

Pet owners’ responsibilities in preventing and controlling parasitic infections in their pets Management of canine and feline faeces

Concluding remarks

References

Plaza Antonio Beltrán Martínez, 1 Centro Empresarial El Trovador planta 8, oficina 50002 Zaragoza, Spain

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+34 976 461 480

Epidemiology IN Small Animal Parasitology. Climate Change and Social, Economic and Political Factors

Epidemiology

IN Small Animal Parasitology

Climate Change and Social, Economic and Political Factors Peter Holdsworth AO Maggie Fisher

Foreword by

Domenico Otranto

23/1/20 8:33

EPIDEMIOLOGY IN SMALL ANIMAL PARASITOLOGY. CLIMATE CHANGE AND SOCIAL, ECONOMIC AND POLITICAL FACTORS

This chapter provides six real world examples of animal movement, including release into the wild, which have resulted in profound changes in parasite populations, whether locally or across a continent. References are from peer-reviewed journals and include case studies, compilations of cases and experimental studies. The implications of such movements are seen in an increased risk of parasite transmission to companion animals and potentially humans.

The examples illustrate how basic activities such as gathering dogs for shows, taking pets on holiday, or reducing control of wildlife after a successful disease eradication scheme can have unforeseen or uncontrolled consequences.

Iryna Kalamurza/ shutterstock.com

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Leishmaniosis Canine leishmaniosis (Fig. 1) is found in approximately 50 of the 88 countries where the disease is found in humans (Alvar et al., 2004).

Figure 1. Cutaneous lesions on the muzzle and ocular changes associated with Leishmania infantum infection.

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IMPACT OF ANIMAL MOVEMENT AND CLIMATE CHANGE

Spread in Europe The classical life cycle of Leishmania infantum in Europe involves transmission by means of Phlebotomus spp. sandflies. Leishmaniosis is a complex disease; in some animals, the onset of clinical signs occurs many months or years following infection, which has historically led to it being the only infection identified after release from six months’ quarantine in the United Kingdom (UK) in the days when all dogs moving to the UK entered via mandatory quarantine.

The Pet Travel Scheme (PETS) (see Chapter 7) has contributed to a dramatic increase in the number of dogs entering the UK and, thereby, to an increase in the number of leishmaniosis cases. The latter could also have been enhanced by the trend of rescuing dogs from Mediterranean countries and importing them into the UK. Within a decade of the introduction of the PETS there were reports of suspected autochthonous disease in the UK, suggesting that other means of transmission could result in dog-to-dog transmission in the absence of Phlebotomus spp. (Shaw, Langton and Hillman, 2009). Between 1997 and 2012, 403 cases of

Figure 2. Approximate EU distribution of endemic canine leishmaniosis in 2008. Adapted from ESCCAP (2011).

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canine leishmaniosis were diagnosed in the UK (Holdsworth, Kramer and Fisher, 2015).

Within the Schengen area, travel from the Mediterranean countries to northern Europe takes place even more easily and this has resulted in infected dogs creating a potentially significant reservoir in northern European countries.

In recent years, the prevalence of canine leishmaniosis (caused by L. infantum) in southern Europe and its seasonal expansion into central France and possibly eastern Europe have all increased. The endemic area in 2008 can be seen in Figure 2, while Figure 3 shows the increased range in 2012.

A combination of factors including increased movement of infected animals (in the UK and Europe) and climate change supporting spread of the sandfly vectors (Figs. 4–6) have been implicated. Infected cats in endemic countries have also been reported.

The prevalence of leishmaniosis is predicted to continue to increase, delivering potential for new endemic foci to establish in central and northern Europe (Pennisi, 2015).

Figure 3. Approximate EU distribution of canine leishmaniosis in 2012, which reveals a small increase in range with respect to 2008. Adapted from ESCCAP (2012).

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EPIDEMIOLOGY IN SMALL ANIMAL PARASITOLOGY. CLIMATE CHANGE AND SOCIAL, ECONOMIC AND POLITICAL FACTORS

Phlebotomus perniciosus

Figure 4. EU distribution of the sandfly Phleboto-

mus perniciosus (January 2019). Adapted from European Centre for Disease Prevention and Control and European Food Safety Authority (2019a).

Phlebotomus perfilewi

Figure 5. EU distribution of the sandfly Phlebotomus perfilewi (January 2019). Adapted from European Centre for Disease Prevention and Control and European Food Safety Authority (2019b).

Spread in the USA Sporadic cases of leishmaniosis (caused

by L. infantum) have been reported in both humans and dogs returning to the United States of America (USA) from endemic areas (Schantz et al., 2005). In 2000, a kennel in New York State reported four Foxhounds infected with L. infantum but with no travel history (Gaskin et al., 2002). By 2005, 60 kennels in 22 states and two Canadian provinces had reported seropositive Foxhounds (Rosypal et al., 2005). Vector-borne transmission in the USA has not been shown (Duprey et al., 2006; Schantz et al., 2005) and both vertical (transplacental or transmammary)

and horizontal (direct contact with infected cells in blood) transmission mechanisms have been postulated (Duprey et al., 2006; Schantz et al., 2005; Gibson-Corley et al., 2008). Transmission has been documented via packed red blood cell transfusion from infected Foxhounds (Owens et al., 2001).

Vertical transmission appears to be a major means of transmission in Foxhounds (Duprey et al., 2006) and has been demonstrated in pups from a single litter born to a leishmaniapositive bitch (Boggiatto et al., 2011).

Canine infection in the USA suggests a possible known health threat if domestic sandfly

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IMPACT OF ANIMAL MOVEMENT AND CLIMATE CHANGE

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Phlebotomus mascitti Legend Present Introduced Anticipated absent Observed absent No data Unknown

Figure 6. EU distribution of the sandfly Phlebotomus mascitti (January 2019). Adapted from European Centre for Disease Prevention and Control and European Food Safety Authority (2019c).

species are capable of Leishmania transmission (Petersen, 2009). A potential sandfly vector, Lutzomyia shannoni, is present in southern and southeastern USA (Duprey et al., 2006). This sandfly is known to bite dogs and other mammals and has been incriminated in the transmission of Leishmania brasiliensi in south and central America (Travi et al., 2002).

Evidence suggests that Lu. shannoni can become infected with L. infantum, but further research is needed to establish the success of the fly as an intermediate host (Petersen, 2009).

With the increasing number of dogs travelling internationally and the expanding range of sandfly vectors due to global warming, new foci of Leishmania infection are likely to appear in previously nonendemic countries.

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EPIDEMIOLOGY IN SMALL ANIMAL PARASITOLOGY. CLIMATE CHANGE AND SOCIAL, ECONOMIC AND POLITICAL FACTORS

International spread with transport of military dogs In Japan, four cases of imported leishmaniosis have been documented in dogs, with two animals originating from Spain (Namikawa et al., 2006; Takahashi et al., 1997) and two from Sicily, Italy (Kawamura, Yoshikawa and Katakura, 2010). Each of the two most recent cases involved a dog that had lived for three years on a US military base before being transferred with its owner to Japan.

The first of these dogs arrived at Yokosuka Base in 2003 and tested positive (rK39 and polymerase chain reaction) for visceral

leishmaniosis in January 2004 (Kawamura, Yoshikawa and Katakura, 2010). In the second case, the dog and owner were transferred to Japan in 2006. The animal was diagnosed with visceral leishmaniosis and treated, before finally being euthanised due to unresolved lesions in May 2008.

Global warming, which causes changes in the distribution of the sandfly vectors, and human-related risk factors, such as travel, migration and urbanisation, may increase the incidence of leishmaniosis (Desjeux, 2001). Military mobility and operations are also a major risk factor for leishmaniosis in humans and canids (Coleman et al., 2006).

The spread and establishment of canine leishmaniosis around the world appears to be supported by the unprecedented movement of infected pets.

Similarly, climate change appears to be supporting the spread and establishment of the sandfly vector of this disease. In the United States of America, vector-borne transmission may be of less importance, with vertical transmission predominating, thus requiring different approaches to control. Veterinary practitioners should be prepared to deal with an increased incidence of canine leishmaniosis and sufficiently informed about the diagnosis, treatment and ongoing management of infected pets.

Rrraum/shutterstock.com

The double impact of pet movement and climate change on the incidence of canine leishmaniosis

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IMPACT OF ANIMAL MOVEMENT AND CLIMATE CHANGE

Echinococcus multilocularis spread in Europe since rabies elimination Echinococcus multilocularis is a cestode that causes a lethal zoonosis in humans in cases where infection establishes and is untreated.

Development of the metacestode stage is slow in humans, taking approximately a decade before clinical signs are seen, with death occurring 10 to 15 years after infection. The definitive hosts are primarily foxes but also racoon dogs, dogs, and cats. Studies have demonstrated that, when infected with the same number of protoscolices (immature tapeworms), foxes produced more worms and more eggs, followed by racoon dogs and dogs. Cats produced the smallest number of eggs (Kapel et al., 2006). On this basis, cats have been described as epidemiologically insignificant as hosts (ESCCAP, 2017), though infected cats may have local significance since they are major hunters and bury their faeces.

Echinococcus multilocularis can be found in many parts of the world, including Russia and Europe. In western Europe, control of the fox population decreased after the successful eradication of rabies, which led to an increase in the number of foxes and thereby to a greater infection pressure from E. multilocularis eggs. This in turn has resulted in an

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increase in human infections (Schweiger et al., 2007) (Fig. 7). Between 2006 and 2015, the area where E. multilocularis is recognised as endemic in foxes increased, with infection identified in westernmost parts of France (Figs. 8 and 9). Formerly an infection-free country, Sweden lost that status when the infection was identified in two foxes (Osterman Lind et al., 2011). The extent to which this represents a true increase in range as opposed to the effect of increased investigation is a matter of scientific debate, with the explanation probably being a mixture of the two. Multifactorial issues (including geographical and political) will dictate the future range of this cestode. The UK retains its E. multilocularisfree status and on that basis, dogs entering the UK from Europe are required to have a cestode treatment within a specified period prior to their date of entry. On a local level, the spread of foxes into urban areas and people choosing to live in periurban rural areas have led to increased opportunities for humans to encounter E. multilocularis eggs.

Definitive hosts are infected when they ingest infected voles, with adult cestodes developing within the small intestine after approximately a month. Small proglottids and eggs that are immediately infective are shed thereafter. It is not unusual for infected dogs to carry eggs in their coats, thus posing a risk for humans stroking and handling them. Among the risk factors identified for human infection are dog ownership, farming, living on a farm and working in forestry, with contamination of soil with eggs representing a significant risk.

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EPIDEMIOLOGY IN SMALL ANIMAL PARASITOLOGY. CLIMATE CHANGE AND SOCIAL, ECONOMIC AND POLITICAL FACTORS

Male

Cases per 100,000 population

0.35

Female

Figure 7. Cases of Echinococcus

0.30

multilocularis human infection by age and gender in the European Union. The preponderance of cases in older people is consistent with the incubation period for the infection. It will take a period of time until the effect on humans of the increased range and prevalence of infected foxes becomes apparent. Adapted from European Centre for Disease Prevention and Control (2016).

0.25 0.20 0.15 0.10 0.05 0.00

0–14

5–14

15–24

25–44

45–64

>65

Age (years)

Figure 8. EU distribution of Echinococcus multilocularis (2006). Adapted from ESCCAP (2007).

Figure 9. EU distribution of Echinococcus multilocularis showing increase in range (2015). Adapted from ESCCAP (2017).

In Europe, the increasing fox populations and increased range of endemic E. multilocularis,, together with the overlap of fox and human communities, pose an increased risk of canine (and feline) infection and zoonotic transfer of this tapeworm.

Jim Cumming/ shutterstock.com

Zoonotic risk of Echinococcus multilocularis

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IMPACT OF ANIMAL MOVEMENT AND CLIMATE CHANGE

Lyme borreliosis and the impact of Siberian chipmunk introduction into Europe The Siberian chipmunk (Tamias sibiricus barberi ) is a ground squirrel (Fig. 10) introduced from Korea to Europe in the 1960s, which became a popular pet especially in the 1980s in France. Siberian chipmunks proved to be nonideal as companion animals, sometimes noisy and capable of biting, which resulted in cases where they were deliberately released into the wild from the 1970s onwards (Marsot et al., 2013). In certain environments they proliferated. Since then 22 populations (Table 1) – 11 of them in France – have been

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identified in Europe, in forests and urban parks (Chapuis et al., 2011). In fact, in certain forests these animals have supplanted red squirrels or voles, with which competition is strong (Beugnet and Chalvet-Monfray, 2013).

Figure 10. Chipmunk (Tamias sibiricus barberi ) (USBFCO/shutterstock.com).

Table 1. Spread of chipmunks in the European Union since the 1960s. Adapted from Marsot et al. (2013).

Decade

1960s

1970s

9 8

Number of countries

2000 onwards

1980s

1990s

ITA*

ITA*

NETH* ITA*

7

AUS

AUS

AUS

AUS

6

GER

GER

GER

GER

5

ITA

ITA

ITA

ITA

4

NETH

NETH

NETH

NETH

SWI

SWI

SWI

SWI

2

3 FRA

FRA

FRA

FRA

FRA

1

BEL

BEL

BEL

BEL

BEL

*Second population infestation FRA, France; BEL, Belgium; SWI, Switzerland; NETH, Netherlands; ITA, Italy; GER, Germany; AUS, Austria.

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EPIDEMIOLOGY IN SMALL ANIMAL PARASITOLOGY. CLIMATE CHANGE AND SOCIAL, ECONOMIC AND POLITICAL FACTORS

Figure 11. Ixodes ricinus female tick (Rasmus Holmboe Dahl/shutterstock.com).

Siberian chipmunks are the host of choice for the nymph stage of Ixodes ricinus ticks (Fig. 11), which can carry Borrelia burgdorferi sensu lato, a bacterium causing Lyme borreliosis. The presence and density of I. ricinus (Fig. 12) are related to the plant cover and to the density of its hosts: micromammals for larvae and nymphs and large mammals (deer, wild boar, foxes, cattle, dogs and humans) for adult ticks (Knapp et al., 2009).

Research revealed the chipmunk’s role in the maintenance, or even in increasing the risk for humans of Lyme disease in the MelunSénart forest in the suburbs of Paris, France (Marsot et al., 2013). According to this study, chipmunks produced nearly 8.5 times more infected tick nymphs than voles or mice, and

therefore contributed to the infection burden of B. burgdorferi sensu lato. The contribution varied between years and seasons according to tick availability. As chipmunks must be a competent reservoir, they likely amplify B. burgdorferi sensu lato infection, hence increasing the risk of Lyme borreliosis in humans.

How climate change may have contributed to this situation remains untested. Weather conditions are known to play a significant role in the survival and activity of rodents, as well as in periods during which ticks are active and are on vegetation on the lookout for hosts. The decreased number of winter days with a temperature below a minimum cutoff value – a consequence of climate change – was defined as a key factor in the increased density of Ixodes ticks and their questing activity during winter periods (Dautel et al., 2008; Gern, Morán Cadenas and Burri, 2008; Lindgren, Tälleklint and Plolfeldt, 2000), and in their hosts’ changes in periods of activity and variations in geographical distribution (Beugnet and Chalvet-Monfray, 2013).

The EU Invasive Alien Species (IAS) Regulation (1143/2014) lists the Siberian chipmunk as an IAS. IAS listings, subject to exemptions, cannot be imported, kept, bred, transported, sold, used or exchanged, allowed to reproduce or released into the wild.

The absence of Siberian chipmunk importation regulations and oversight in Europe has resulted in feral populations establishing and expanding.

Because chipmunks are a preferred host for Ixodes ricinus ticks, they act as amplifiers of the disease agent for human Lyme borreliosis and are now problematic due to the environmental risk they pose in the tick season.

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Gabor Tinz/ shutterstock.com

Impact of Siberian chipmunk introduction on endemic Lyme borreliosis

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IMPACT OF ANIMAL MOVEMENT AND CLIMATE CHANGE

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Legend Present Introduced Anticipated absent Observed absent No data Unknown

Figure 12. Ixodes ricinus EU distribution (June 2018). Adapted from European Centre for Disease Prevention and Control and European Food Safety Authority (2018).

Baylisascaris in Germany and the impact of Raccoon INTRODUCTION The raccoon (Procyon lotor) is the definitive host of the roundworm Baylisascaris procyonis, responsible for the disease baylisascariosis. This roundworm is considered a potential cause of visceral, ocular and neural larva migrans (Fig. 13) in mammals, including humans (Bauer, 2013). Raccoons were deliberately introduced into Germany from North America in the 1920s to be bred for their pelts.

A controlled release by game authorities of two

breeding pairs into the wild occurred near Kassel in April 1934. The animals initially became well established in central Germany, and from there have been spreading in range. Competition in the wild is high, with dense raccoon populations centred around the German states of Hesse, Brandenburg and Saxony-Anhalt.

Because of this pressure, young male raccoons are migrating hundreds of kilometres to other parts of the country.

While the raccoon is the natural host for B. procyonis, the domestic dog is also susceptible and can end up shedding nematode eggs. Infected dogs are also susceptible to developing neural larva migrans (Rudmann et al., 1996). This potential zoonotic infection has become problematic due to the success of the raccoon host in the German environment.

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EPIDEMIOLOGY IN SMALL ANIMAL PARASITOLOGY. CLIMATE CHANGE AND SOCIAL, ECONOMIC AND POLITICAL FACTORS

Figure 13. Baylisascaris procy-

onis larva migrating through the brain of a mouse 12 days postinfection. Image courtesy of Prof. Christian Bauer, Institute of Parasitology, Justus Liebig University Giessen, Germany.

The EU approach to managing the problem focuses on dealing with the established raccoon population and also preventing further importations of the animal. Exterminating the raccoon is recommended on the ground that it could pose a threat to biodiversity. The hunting bag for 2010/11 season in Germany included more than 67,000 raccoons (“Jahresstrecken Neozoen�, 2012). In the past, raccoons were

also imported to Poland and Russia, where they are now well established. The EU Invasive Alien Species (IAS) Regulation (1143/2014) lists the raccoon as an IAS. As mentioned earlier, IAS listings, subject to exemptions, cannot be imported, kept, bred, transported, sold, used or exchanged, allowed to reproduce or released into the wild.

Dogs are at risk of adult and larva migrans infection with Baylisascaris procyonis and humans of the larva migrans form of the infection as a result of the presence of large numbers of raccons (the natural host) that were introduced, released and have now established large populations in Europe, particularly Germany.

Ondrej Prosicky/ shutterstock.com

Baylisascariosis in raccoons and its negative impact in Germany

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