‘Reservoir dogs’: The emerging zoonotic risk associated with European dog imports to the UK

Abstract

Background

The movement of dogs from continental Europe to the UK poses a growing public health threat due to the associated risk of disease incursions. Current legislation is insufficient to address the risks and pre‐import control measures are focused only on rabies virus and the fox tapeworm Echinococcus multilocularis.

Methods

We conducted a scoping review to summarise the major zoonotic pathogens and vectors associated with imported dogs (including rabies virus, Brucella canis and exotic tick species), and explore their potential to become established in the UK. Gaps in existing research and surveillance are highlighted, and potential measures to strengthen control are discussed.

Limitations

Only English‐language sources were included in the literature search. Data on imported dogs and their disease burden are limited.

Conclusions

Raising awareness of the risks among veterinary staff—who play a central role in recognising, managing and preventing imported zoonoses—is integral to a One Health approach.

INTRODUCTION

The domestic dog (Canis lupus familiaris) co‐evolved alongside people and continues to provide social, health and economic benefits in the UK and worldwide. ¹ However, this close relationship carries public health risks. Dogs serve as hosts and reservoirs for many zoonotic pathogens, and they bring these pathogens and their vectors into human proximity, facilitating disease spread.

Several zoonotic pathogens and vectors have a lower or absent UK burden compared mainland Europe. ² Proximity and relative freedom of movement facilitate high dog import rates from Europe to the UK each year. ³ , ⁴ Current legislation specifies pre‐import control measures for only rabies virus and the fox tapeworm Echinococcus multilocularis, and there is no requirement for tick treatment. This enables introduction of non‐endemic pathogens and vectors of veterinary and public health concern via dog travel. Frequent subclinical canine infection and lack of screening mean that outbreaks may be detected at a later stage when intervention is more challenging. Veterinary staff and dog owners are often underinformed of this risk. ⁵

While previous studies highlight the dangers of imported canine diseases to UK dogs, ² , ⁶ , ⁷ , ⁸ , ⁹ fewer focus on the zoonotic threat. ¹⁰ Here, we explore the public health risk presented by infectious diseases and vectors carried by dogs travelling from continental Europe to the UK, identify current research gaps and discuss potential improved control measures.

METHODS

We conducted a literature review of zoonotic pathogens and vectors relevant to European dog imports to the UK. Literature searches were conducted on PubMed, with search terms, including combinations of keywords relating to dog travel, location and zoonotic pathogens or vectors. Species of interest were explored with further searches, and reference lists of relevant publications appraised for secondary sources. We included English‐language publications between 2000 and 2025, comprising peer‐reviewed research and reviews, surveillance reports and some grey literature from governments and organisations. In addition, a freedom of information request was submitted to Defra (FOI2025/19899) regarding dog import numbers from 2018 to 2024.

RESULTS

Current status of UK dog imports

There are currently around 8.5 million dogs in the UK, ¹¹ with an annual demand for almost one million new puppies. ⁵ Following a reduction during the COVID‐19 pandemic, dog import rates have remained high (Figure 1a). In 2024, there were 335,451 non‐commercial (pet) imports to Britain, almost twice as many as in 2021 and more than pre‐pandemic numbers.

FIGURE 1.

(a) Dog imports to Great Britain (GB) in 2018‒2025. ³ , ⁴ Due to collection methods, the data are related to GB rather than the UK, and non‐commercial imports are not subdivided by origin. Commercial imports comprise pedigree dog sales and charity imports; non‐commercial imports are typically pets travelling with owners, although some charities may incorrectly import rescues non‐commercially. ¹¹ (b) Numbers of illegally imported dogs intercepted at the GB border in 2021‒2025. ⁴

Dogs imported from Europe can be categorised as follows:

• Resident UK dogs returning from holiday with their owners:

The relative ease of taking a pet dog to nearby Europe is attractive to many. Unfortunately, owners are frequently underinformed about the importance of disease and vector prevention, and a small proportion of these dogs will return with a non‐endemic disease. Some pathogens, such as the protozoan Leishmania infantum, cause more severe disease in UK dogs, which lack immunity compared with endemic canine populations. ¹²

• Stray dogs for adoption, imported by charities and other organisations:

Many organisations facilitate the adoption of street dogs, mainly from Eastern Europe. UK dog imports from Romania increased fivefold between 2014 and 2019. ¹³ This facilitates spread of pathogens such as Brucella canis, among other health and welfare concerns. ¹⁴ There is wide variation in pre‐export veterinary care and disease screening and in owner awareness of risk. ⁵ Some may arrive with poor health status. For example, one cohort had high owner‐reported pathogen and ectoparasite burdens. ¹¹

• Commercial pedigree imports, imported by individual breeders and large businesses:

Increasing rates of obtaining pedigree puppies and dogs from abroad are likely due to the relative ease of breeding overseas, with rising UK dog prices and high demand. ⁵ These dogs often cross multiple borders from areas of higher infectious disease prevalence. ⁵ The importation of pregnant bitches and dogs from large breeding establishments raises particular concern for B. canis transmission. ¹⁴

• Illegal imports, smuggled by individuals or organised crime groups:

Lax breeding regulations and high demand for pedigree puppies facilitate the illegal dog trade in Europe. ¹⁵ The scale of dog smuggling is difficult to estimate, but a survey conducted in 2025 found that 20% of UK small animal veterinary surgeons had seen a suspected illegally imported puppy in the previous 12 months. ¹⁶ The numbers of intercepted dogs have reduced significantly since 2021 (Figure 1b). However, without evidence to suggest a true reduction in smuggling, this likely represents a lack of interception. ⁴ Smuggled dogs present a high disease risk because they are often unsuitably young, without rabies vaccination or tapeworm treatment, and may be from areas of higher disease burden. ¹⁵

Factors determining the rate of UK dog imports and associated disease risk are outlined below:

• Legislation:

Currently, imported dogs are subject to control for rabies virus and E. multilocularis. All dogs entering the UK from Europe must be at least 15 weeks old, with a microchip and rabies vaccination. Deworming treatment is required unless entering from another E. multilocularis‐free country. ¹⁷ In 2012, requirements for rabies vaccine serology testing (for low‐risk countries) and tick treatment were removed. Although we lack data on the effectiveness of these control measures, their removal may have increased infectious disease risk. ⁶ Current regulations are likely insufficient to prevent the entry of rabies virus, E. multilocularis and many other pathogens that are subject to no controls. Lack of mandatory tick treatment may also allow introduction of vectors to dogs. ¹⁸ Infectious disease risk is also affected by inadequate regulation of dog imports and measures to control the illegal dog trade.

• Sociopolitical factors:

Societal and political trends, such as increased demand during the COVID‐19 pandemic, ¹⁹ , ²⁰ influence the number and type of dogs imported. Barriers to UK adoption may stimulate the sourcing of dogs from overseas. Reasons cited for adopting a rescue dog from abroad include responding to online marketing, perceived poor welfare, concern that the dog may be killed and failure to meet criteria of UK rescues. ¹¹ Geopolitical events, such as displacement of dogs with owners due to conflict, also affect risk. ²¹

• Environmental factors:

Climate‐induced expansion of many vector species is predicted to continue. Temperature increases of 1°C‒2°C can have wide‐reaching effects, including altered transmission patterns of UK‐endemic vectors and emergence of new species. ²² Further expansion of the distribution and active season of endemic Ixodes ricinus (tick vector of Borrelia burgdorferi and other pathogens) is expected. ²³ Recent years have seen UK emergence of mosquito vectors of Dirofilaria species and the fly vector of Thelazia callipaeda, with predicted pathogen emergence. ²⁴ , ²⁵ Milder temperatures have allowed expansion of the phlebotomine sandfly (vector of Leishmania species) to northern Europe. ²⁶ , ²⁷ Establishment of invasive ticks, such as Rhipicephalus sanguineus, is also more likely as temperatures rise. ²⁸

Imported canine pathogens presenting a zoonotic risk

The zoonotic pathogens most relevant to dog importation from continental Europe to the UK are summarised in Table 1 and the text below. We included pathogens absent from the UK or with a substantial prevalence differential compared to Europe, such that importation would meaningfully alter zoonotic risk. Anaplasma phagocytophilium and B. burgdorferi, although endemic in the UK, are included due to higher European prevalence. ²⁹ We excluded many pathogens (e.g., Toxocara canis, Leptospira species and Giardia intestinalis) with established high prevalence in resident dogs. Babesia species are not discussed as the European zoonotic species lack a canine reservoir. ³⁰

TABLE 1.

Pathogens endemic in Europe that may be imported to the UK via dogs.

Pathogen	Vector	Epidemiological role (dogs)	European endemicity	UK disease status (dogs)
Viruses
Rabies virus	None	Reservoir 31	Parts of Eastern Europe 32	Eliminated 32
Tick‐borne encephalitis virus	Ixodes ticks; I. ricinus primary vector in Europe and endemic in the UK 33	Accidental host 34	Most of Europe 35	Potential sporadic autochthonous 36
Bacteria
Anaplasma phagocytophilium	Ixodes ticks; I. ricinus primary vector in Europe and endemic in the UK 33	Potential reservoir 37	Most of Europe 37 , 38	Emerging 37
Borrelia burgdorferi	Ixodes ticks; I. ricinus primary vector in Europe and endemic in UK 33	Accidental host 23	Most of Europe 23	Emerging 23
Brucella canis	None	Reservoir 39	Most of Europe 14	Sporadic imported 40
Ehrlichia canis, Ehrlichia chaffeensis	Rhipicephalus sanguineus ticks; emerging in UK 33	Reservoir (E. canis), potential reservoir (E. chaffeensis) 23	E. canis in Mediterranean Europe 38 E. chaffeensis emerging 23	Sporadic imported and autochthonous 41 , 42
Francisella tularensis	Ticks (including I. ricinus, Dermacentor reticulatus, likely others) and mosquitoes, particularly Aedes species; several vectors endemic in UK 43	Accidental host 43	Most of Europe 44	Absent 45
Rickettsia conorii	R. sanguineus ticks 46 ; emerging in UK 33	Potential reservoir 23	Mediterranean Europe 47	Sporadic imported 48
Protozoa
Leishmania infantum	Phlebotomus species sandflies in Europe; absent in UK 49	Reservoir 26	Mediterranean Europe 26	Sporadic imported and autochthonous 50 , 51 , 52 , 53
Helminths
Dirofilaria immitis, Dirofilaria repens	Mosquito genera Anopheles, Culex, Aedes and others 54 ; several species endemic in the UK 55	Reservoir and definitive host 56 , 57	Mediterranean Europe 54	Sporadic imported 57
Echinococcus multilocularis	None	Reservoir and definitive host 10	Most of Europe 27	Absent 44
Thelazia callipaeda	Fly Phortica variegata; present in southern UK 25	Reservoir and definitive host 25	Most of Europe 58	Sporadic imported 58
Arthropods
Linguatula serrata	None	Reservoir and definitive host 59	Parts of Europe 59	Sporadic imported and autochthonous 60

Note: Prevalence and distribution are likely underestimated due to limitations in data and diagnostic tests. Many dogs harbour coinfection due to factors such as common vectors and poor health status. ²⁹ , ⁶¹ Definitions: reservoir—species in which a pathogen is maintained and transmitted to a defined group (here, people); accidental host—species which may be infected without meaningfully contributing to onward transmission; definitive host—species in which adult parasites mature and reproduce sexually (vs. intermediate host, in which immature stages develop). ⁶² , ⁶³

Dogs can influence zoonotic transmission through several epidemiological pathways. They may directly introduce pathogens for which they are reservoirs, such as B. canis, ⁴⁰ or accidental hosts (see Table 1 footnote for definitions). Dogs also function as transport hosts for vectors, including ticks, increasing opportunities for human exposure to vector‐borne pathogens. ³⁰ For several pathogens, such as B. burgdorferi, canine cases are sentinels for human disease. ⁶⁴

Viruses

Rabies

Rabies, caused by Lyssavirus species, results in progressive neurological signs and is almost uniformly deadly once signs develop. ³¹ Classical (non‐bat) rabies is most commonly transmitted to people by dog bites, facilitated by the virus's induction of aggression in many infected dogs. ³²

Vaccination of animal reservoirs (dogs and wild carnivores) has significantly reduced the incidence of classical rabies in Europe. ⁶⁵ Most countries have achieved elimination, including the UK, which has been rabies‐free since 1922. ⁶⁶ Western Europe has seen sporadic imported cases, ³² with subsequent localised outbreaks in Italy and Greece. ⁶⁷ All imported animal cases since 2000 were due to illegal movements. ⁶⁶ The virus persists in parts of Eastern Europe due to spillover from bordering endemic countries, ³² , ⁶⁵ , ⁶⁸ with a fatal autochthonous human case in Romania in 2025. ⁶⁹

Importation of an animal with rabies is the most likely mode of UK introduction. ⁶⁶ Pets from low‐risk countries must wait 3 weeks after rabies vaccination before entering the UK; for high‐risk countries, a rabies vaccine serology test and a 3‐month wait are also required. ⁷⁰ All European countries are categorised as low risk, although not all are rabies free.

Concerns arise from this approach. Vaccine failures have been reported. ⁷¹ , ⁷² Additionally, the long viral incubation period may allow importation of incubating cases. In 2008, a dog imported from Sri Lanka was diagnosed with rabies in a UK quarantine facility. ⁷³ , ⁷⁴ Unvaccinated imported dogs are quarantined for an inadequate 3 weeks post‐vaccination. ⁶ Illegally imported dogs, which are commonly unvaccinated and enter unidentified, present the highest risk. A naïve reservoir population, including dogs (not routinely vaccinated unless travelling) and wildlife, means that UK endemicity is possible without swift detection of imported cases. ³²

Tick‐borne encephalitis

Neurotropic tick‐borne encephalitis virus (TBEV) is spread predominantly by I. ricinus in Europe and has diverse wildlife reservoirs. ³⁴ Dogs are a rare accidental host and may display progressive neurological signs, including paralysis and seizures. ³⁶ While most human TBEV infections are asymptomatic, severe neurological signs may result. ⁷⁵

TBEV infection is endemic in Europe (estimated incidence of 2.19 cases per 100,000), with an expanding distribution. ³⁵ The virus has recently been detected in ticks and people in the UK, ⁷⁵ with potential canine cases, although similarity to endemic Louping Ill virus complicates diagnosis in dogs. ³⁶ , ⁷⁵ The tick vector (I. ricinus) and many sylvatic reservoirs are endemic in the UK, ⁷⁶ although public health risk and potential for wider spread are considered low. ⁷⁷

Bacteria

Anaplasma phagocytophilium

A. phagocytophilium causes human and canine granulocytic anaplasmosis. Spread by Ixodes ticks, its animal hosts include dogs. ⁷⁸ Infection may result in fever, joint pain and low white blood cell and platelet counts in people and dogs. ²³ However, many infected dogs are asymptomatic. ⁷⁹

A. phagocytophilium is endemic across most of Europe and emerging in the UK. ³⁸ The primary vector, I. ricinus, is the predominant UK tick species. ³⁷ The prevalence of A. phagocytophilium was 4.6% among ticks collected from one cohort of UK dogs. ³⁷ The UK also has many other potential reservoirs, including wild and domestic ruminants. ⁷⁸

Borrelia burgdorferi

These spirochaete bacteria have diverse wildlife reservoirs, and their primary European vector is I. ricinus. ³³ , ⁸⁰ In people, following the classic ‘bullseye’ rash, symptomatic Lyme disease presents as fever, joint pain and neurological signs. ²³ Dogs are accidental hosts and may develop similar signs to people or have asymptomatic carriage. ⁸¹

Lyme disease is endemic across most of mainland Europe, with an annual incidence of around 128,000 cases and much local variation. ⁸² , ⁸³ , ⁸⁴ It is emerging in the UK, with regional hotspots in Scotland and southern England. ⁸⁵ UK prevalence is likely underestimated and expected to increase as climate change extends the vector's active season. ⁶⁴ , ⁸⁶ The mean prevalence of B. burgdorferi in British ticks is estimated to be 3.6% (vs. 12.3% in Europe). ²³ , ⁸⁷ Two studies found prevalences of 0.5% and 2.0%, respectively, in ticks removed from UK pet dogs. ⁶⁴ , ⁸⁸

Brucella canis

B. canis is one of several species causing brucellosis in people and animals. It is transmitted principally via reproductive secretions from dogs, its primary reservoir. ⁸⁹ Infected dogs may display chronic and wide‐ranging signs, including discospondylitis, infertility and abortion. ¹⁴ In people, severe cases develop meningitis and septicaemia. ⁹⁰ Asymptomatic carrier status is common in both people and dogs. ¹⁴ , ⁹⁰ Innate antibiotic resistance necessitates prolonged courses in people. ⁹¹ Infection is almost impossible to cure in dogs; hence, euthanasia is often advised. ⁹²

B. canis is endemic in dogs in Eastern Europe. ¹⁴ Rare human cases occur, mainly in those with compromised immune systems or prolonged close contact with dogs. ⁹² Human and canine prevalence are likely underestimated due to lack of screening. ⁸⁹

In the UK, B. canis is emerging in dogs. Before 2020, just three imported canine cases had been confirmed. ⁹² However, incidence has risen sharply since 2020 (Figure 2), likely due to rising dog imports from endemic countries such as Romania and no mandatory pre‐import screening. ⁹⁰ , ⁹² Autochthonous dog‐to‐dog spread is now reported. ⁹⁰ The first zoonotic transmission occurred in 2022, from a pregnant rescue dog imported from Belarus to its immunocompromised fosterer, ⁹³ with one additional case since in a veterinary staff member. ⁹⁰

FIGURE 2.

Incidence of Brucella canis in UK dogs in 2019‒2024. ⁹² , ⁹⁴ , ⁹⁵ Lack of routine surveillance means these numbers are likely underestimated.

UK zoonotic risk is considered low but is higher for dog owners, immunocompromised people and veterinary staff. ⁹⁰ Thus far, person‐to‐person spread has not been reported. ⁹⁰ , ⁹² B. canis has been reportable since 2022, while other Brucella species are notifiable and under stricter controls due to higher zoonotic risk. ⁹² In late 2025, Defra announced dogs that are commercially imported from Romania must be screened for B. canis before entering the UK. ⁹⁶

Ehrlichia canis and Ehrlichia chaffeensis

Spread by R. sanguineus, these bacterial species cause human and canine monocytic ehrlichiosis. In dogs, signs include fever, lethargy and coagulation disorders; rare human infection has similar symptoms. ⁴⁶

While E. canis is widely distributed in dogs across Europe, human cases are uncommon. ⁹⁷ E. chaffeensis is emerging in people and dogs in Europe. ²³ However, serological cross‐reactivity complicates the interpretation of species prevalence. ²³ The UK sees sporadic imported canine E. canis cases, and in 2012, two autochthonous cases were reported in untravelled dogs in southeast England. ⁴¹ E. chaffeensis has not been reported in the UK to date. ²³ Recent UK detection of R. sanguineus may facilitate pathogen emergence, although likelihood of establishment is low. ⁹⁸

Francisella tularensis

In people, tularaemia causes fever, muscle pain and lymphadenopathy, with potential severe complications. ⁴³ Transmission routes include vectorial (mosquitoes and ticks), direct contact with animal reservoirs and environmental exposure. ³³ , ⁴³ , ⁴⁶ In animals, severity varies from asymptomatic carriage to peracute illness and death. ⁴³ Dogs are considered an accidental host but may transmit to people given close proximity, and occupational exposure is a risk factor. ⁴³ , ⁹⁹ , ¹⁰⁰

Tularaemia is endemic across most of Europe, with an average incidence of 0‒17.9 cases per 100,000 reported between 1997 and 2013. ⁴³ While tularaemia is considered absent from the UK, ⁴⁵ a 2023 human case without recent travel history raised concerns about autochthonous exposure from an animal or tick. ⁴⁵ Epidemic or endemic spread is possible if F. tularensis was imported, given its contagiousness and presence of environmental and wildlife reservoirs. ⁴⁵ , ¹⁰¹ However, the probability of establishment is unknown.

Rickettsia conorii

R. conorii, spread by R. sanguineus ticks, causes Mediterranean spotted fever in dogs and people. ⁴⁶ Symptoms in people include ‘tache noire’ rash, fever and malaise, with potentially fatal complications. ²³ Underdiagnosis in dogs is likely due to frequent subclinical presentation. ⁴⁶ Contact with the canine reservoir is a risk factor for human infection. ²³

R. conorii is endemic across Mediterranean Europe, with a mean seroprevalence of 3.9%‒23% in people and up to 80% among dogs in one endemic area. ⁴⁶ , ⁴⁷ Recent emergence in people in Switzerland, Poland and Denmark has been linked with import of infected ticks on dogs. ⁴⁴ The UK has reported no autochthonous cases; however, the recent detection of the tick vector may allow future emergence. ⁹⁸

Protozoa

Leishmania infantum

This parasite causes human and canine visceral leishmaniosis (CVL). Dogs are the principal reservoir. ¹⁰² It is predominantly spread by sandflies (Phlebotomus species) ¹⁰³ ; salivary, vertical and venereal transmission between dogs has also been reported. ¹⁰⁴ , ¹⁰⁵ In people, symptomatic infection (including fever, anaemia and splenomegaly) is nearly always fatal if untreated. ¹⁰² In dogs, severity varies (from asymptomatic to severe skin disease, fever, weight loss, onychogryphosis and anaemia) and infection is typically lifelong. ¹⁰⁶ Treatment aims to manage clinical signs, reduce parasite load and improve quality of life, but it is rarely curative.

L. infantum and its sandfly vector are endemic in Mediterranean Europe, where the average CVL seroprevalence is 23.3%. ²⁶ The parasite is also emerging in northern Europe, due to dog movement and expanding vector distribution as a result of climate change. ²⁶ , ¹⁰⁷

Absence of the sandfly vector has prevented endemic CVL transmission in the UK. ⁵⁰ However, increasing imported cases have been reported, particularly in southeast England, although lack of surveillance hinders prevalence estimates. ⁵⁰ Three autochthonous CVL cases were diagnosed between 2018 and 2019 in untravelled dogs. ⁵¹ , ⁵² , ⁵³ Currently, potential for UK zoonotic transmission or significant autochthonous spread of L. infantum is extremely low due to vector absence. However, if warmer temperatures enable sandfly expansion to the UK, there is potential for endemicity due to the naïve canine reservoir population. ⁵⁰

Helminths

Dirofilaria immitis and Dirofilaria repens

These filarial nematodes are spread by various mosquito species. ⁵⁶ Dogs are their primary reservoir, in which asymptomatic infection is common. ²⁴ Colonisation of the canine heart and pulmonary vasculature by D. immitis (also known as heartworm) may cause coughing and heart failure, ⁵⁷ while D. repens colonises the skin and may cause subcutaneous nodules. ⁵⁶ Human infections are rare and most commonly due to D. repens, with variable presentation. ⁵⁶

Both species are endemic in Mediterranean Europe and have expanded northwards in the past two decades. ⁵⁷ Pooled European canine D. immitis prevalence is around 10.5%. ⁵⁴ Neither species is UK endemic, but increasing imported canine cases are seen. ⁵⁵ There is potential for endemicity, particularly for D. repens, which has spread more rapidly through northern Europe. ²⁴ Several mosquito vectors are already present in the UK; the key vector Aedes albopictus has been detected sporadically, with endemicity predicted as temperatures rise. ⁵⁵ , ¹⁰⁸

Echinococcus multilocularis

In the intermediate human host, E. multilocularis causes hepatic alveolar echinococcosis, which is generally fatal without treatment. ⁴⁴ Asymptomatic animal reservoirs include dogs, foxes (definitive hosts) and wildlife. ²⁷

The parasite's range is expanding in Europe, except in a few non‐endemic countries, including the UK. ²⁷ European incidence of alveolar echinococcosis varies by country, averaging 0.21 cases per 100,000 in 2023. ²⁷

Dog travel is key for E. multilocularis spread, and is the most likely mode of UK introduction. ¹⁰⁹ Modelling suggests human cases are highly likely if pre‐entry deworming treatment was abandoned. ¹⁰⁹ The presence of several native sylvatic reservoirs means the parasite would be challenging to eradicate if it becomes established. ²⁸ , ⁴⁴ Prevention, via maintaining current controls and reducing illegal imports (likely without deworming treatment), is therefore vital.

Thelazia callipaeda

The eye worm nematode is spread by its fly vector and intermediate host, Phortica variegata. ⁵⁸ Adult nematodes colonise the canine and human conjunctiva, resulting in ocular signs. ²⁵ T. callipaeda has emerged across most of Europe in the past two decades, spreading as far north as France. ⁵⁸ The UK has seen sporadic imported canine cases since 2016. ⁵⁸ There is potential for endemicity, with vector presence in southern England (and potentially suitable conditions across much of UK), and potential sylvatic reservoirs. ²⁵

Arthropods

Linguatula serrata

L. serrata, known as tongue worm, is a pentastomid parasite of mammals. ⁵⁹ Dogs are infected by consuming infective larvae in raw offal, and colonisation of the nasopharynx produces respiratory signs or asymptomatic carriage. ¹¹⁰ Rare human infection occurs via raw meat ingestion or exposure to nasal discharge and faeces of infected dogs. ⁵⁹

L. serrata is infrequently reported in Europe, and prevalence data are limited. ⁵⁹ The UK has recently seen several imported cases in dogs from Romania ⁶⁰ and a single autochthonous case in a raw‐fed dog. ¹¹¹ Lack of surveillance may mean the zoonotic risk is underestimated.

Imported vectors associated with dog imports

The vector‐borne canine zoonoses that are current or potential threats to the UK are summarised in Figure 3 and the text below.

FIGURE 3.

Schematic of vector‐borne zoonoses of dogs that pose a UK public health threat, created in BioRender. Borrelia burgdorferi and Anaplasma phagocytophilium are the two species currently established in the UK. ³⁷ , ⁸⁵

Ticks are the main vectors of concern associated with dogs because of their direct attachment. Dogs play a key role in bringing infected ticks into proximity with people and wildlife reservoirs. Various tick species have emerged throughout continental Europe and the UK due to dog travel, climate change and other factors. ⁸⁸ , ¹¹² , ¹¹³ , ¹¹⁴ The abolishment of mandatory pre‐entry tick treatment may facilitate introduction of exotic species to the UK. ⁶ , ⁴⁴ I. ricinus (vector of A. phagocytophilium, B. burgdorferi, F. tularensis and TBEV) is the predominant UK tick species. ¹¹⁵ R. sanguineus (vector of E. canis, E. chaffeensi and R. conorii) has emerged since its introduction via dog travel in 2012. ⁹⁸ R. sanguineus and other non‐native ticks, such as Dermacentor reticulatus and Hyalomma species, have been identified on untravelled dogs in the UK, although establishment is unlikely at current temperatures. ² , ¹¹⁵

Although not imported directly on dogs, fly vectors spread several zoonotic pathogens. The northwards expansion of sandflies (Phlebotomus species) is modelled to continue with climate change, ¹⁰⁷ with L. infantum emergence. P. variegata, the vector of T. callipaeda, is endemic in the southern UK and is predicted to expand. ²⁵ Finally, mosquitoes, including invasive A. albopictus, are associated with spread of pathogens, including Dirofilaria species. ²

CONCLUDING REMARKS AND FUTURE ACTIONS

There is a lack of disaggregated data on the numbers of imported dogs and their disease burden. The pathogens discussed herein have variable UK prevalence, and dogs play different roles in their spread. Currently, most are introduced sporadically without sustained onward transmission. Climate change has influenced the expansion of several European vectors and pathogens, including mosquitoes (for Dirofilaria species), sandflies (for L. infantum) and R. sanguineus (for Ehrlichia species). As climate change may exacerbate over half of human infectious diseases, ¹¹⁶ further shifts in epidemiology are expected, facilitated by changing land use and urbanisation. ¹¹⁵

With high dog numbers entering the UK from Europe, there is a growing need to consider the zoonotic implications. Imported dogs are not a homogenous group; most holidaying pet dogs present low risk, while illegally imported dogs and street dogs from Eastern Europe likely carry higher zoonotic risk. ⁴² , ¹¹⁷ The recent increase in imported B. canis cases with subsequent autochthonous transmission provides an important paradigm.

As risk varies by pathogen and import pathway, targeted controls are likely more effective than blanket measures (Figure 4). Further research is required to inform evidence‐based policy, including cross‐sectional studies quantifying disease burden in resident imported dogs and those scheduled for importation. Given resource limitations, canine disease surveillance should be proportionate to zoonotic risk, and human surveillance tailored to high‐risk groups. Current initiatives, such as the tick surveillance scheme, are invaluable to clarify UK vector endemicity. ¹¹⁸

FIGURE 4.

Schematic summarising current challenges to control of zoonoses introduced by dog travel to the UK and suggested mitigations.

Existing legislation should be reviewed and, where appropriate, updated in line with evidence. The UK's exit from the EU offers an opportunity to reassess biosecurity measures as an island nation with defined entry points. The BVA advocates for a UK‒EU agreement facilitating trade while allowing necessary divergence on biosecurity. ¹¹⁹ Australia and New Zealand provide examples of non‐land bordered countries with more rigorous pre‐entry requirements. ¹²⁰ , ¹²¹

Potential legal interventions could include the following:

• extension of the pre‐import waiting period after rabies vaccination from 3 weeks to 3 months;

• reintroduction of pre‐import tick treatment, informed by pilot studies to quantify public health benefit;

• pre‐import B. canis screening in all endemic areas;

• enhanced border checks to intercept illegally imported dogs;

• improved accountability for organisations importing high dog numbers, including and clearer health and welfare responsibility.

The impact of existing and future measures is contingent on their enforcement and compliance. Reforms in the Animal Welfare Act 2025, including increasing the minimum age of imported puppies, are a positive step. ¹²² However, disease control and welfare benefits may be limited without parallel investment in border enforcement. The introduction of B. canis screening for commercial dog imports from Romania omits key groups, including misclassified rescue imports, ¹¹ pets travelling with owners, illegal imports and dogs from other endemic regions. Proposed interventions must also balance benefits against potential harms, such as the contribution of tick treatment to insecticide resistance and environmental contamination. ¹²³

Early detection and proportionate response remain central to control of emerging pathogens and vectors. Improved surveillance and further research are required to better quantify current and future zoonotic risks associated with canine imports from Europe. Vigilance among UK veterinary staff and a One Health approach (integrating veterinary, medical, research and policy sectors) are essential to ensure that these risks identified early and managed effectively.

AUTHOR CONTRIBUTIONS

Poppy Simonson conceived the study, performed the literature searches and wrote the manuscript. Tapan Bhattacharyya and Michael A. Miles advised on the study scope and direction and revised drafts of the manuscript.

CONFLICT OF INTEREST STATEMENT

The authors declare they have no conflicts of interest.

FUNDING INFORMATION

The authors received no specific funding for this work.

ETHICS STATEMENT

Ethical approval was not required as this was a review of the existing literature and no new data were generated.

DATA AVAILABILITY STATEMENT

Data sharing is not applicable to this article as no datasets were generated or analysed during the current study.