Benjamin Cull

An entomological review of invasive mosquitoes in Europe.

Among the invasive mosquitoes registered all over the world, Aedes species are particularly frequent and important. As several of them are potential vectors of disease, they present significant health concerns for 21st century Europe. Five species have established in mainland Europe, with two (Aedes albopictus and Aedes japonicus) becoming widespread and two (Ae. albopictus and Aedes aegypti) implicated in disease transmission to humans in Europe. The routes of importation and spread are often enigmatic, the ability to adapt to local environments and climates are rapid, and the biting nuisance and vector potential are both an ecomonic and public health concern. Europeans are used to cases of dengue and chikungunya in travellers returning from the tropics, but the threat to health and tourism in mainland Europe is substantive. Coupled to that are the emerging issues in the European overseas territorities and this paper is the first to consider the impacts in the remoter outposts of Europe. If entomologists and public health authorities are to address the spread of these mosquitoes and mitigate their health risks they must first be prepared to share information to better understand their biology and ecology, and share data on their distribution and control successes. This paper focusses in greater detail on the entomological and ecological aspects of these mosquitoes to assist with the risk assessment process, bringing together a large amount of information gathered through the ECDC VBORNET project.

Sampling strategies for phlebotomine sand flies (Diptera: Psychodidae) in Europe

The distribution of phlebotomine sand flies is widely reported to be changing in Europe. This can be attributed to either the discovery of sand flies in areas where they were previously overlooked (generally following an outbreak of leishmaniasis or other sand fly-related disease) or to true expansion of their range as a result of climatic or environmental changes. Routine surveillance for phlebotomines in Europe is localized, and often one of the challenges for entomologists working in non-leishmaniasis endemic countries is the lack of knowledge on how to conduct, plan and execute sampling for phlebotomines, or how to adapt on-going sampling strategies for other haematophagous diptera. This review brings together published and unpublished expert knowledge on sampling strategies for European phlebotomines of public health concern in order to provide practical advice on: how to conduct surveys; the collection and interpretation of field data; suitable techniques for the preservation of specimens obtained by different sampling methods; molecular techniques used for species identification; and the pathogens associated with sand flies and their detection methods.

Brown dog tick infestation of a home in England

PUBLIC Health England (PHE) recently investigated a tick infestation in a family home in Essex (East of England) during September 2014. Specimens removed from two pet dogs and within the property were submitted to the PHE Tick Recording Scheme and identified as the brown dog tick, Rhipicephalus sanguineus (15 males, 14 females and one nymph), a non-native species. House infestations are rarely documented in the UK (Best and others 1969, Fox and Sykes 1985) but may become more common with the increased importation of R …

Ticks and Borrelia in urban and peri-urban green space habitats in a city in southern England.

Ticks are becoming increasingly recognised as important vectors of pathogens in urban and peri-urban areas, including green space used for recreational activities. In the UK, the risk posed by ticks in such areas is largely unknown. In order to begin to assess the risk of ticks in urban/peri-urban areas in southern England, questing ticks were collected from five different habitat types (grassland, hedge, park, woodland and woodland edge) in a city during the spring, summer and autumn of 2013/2014 and screened for Borrelia burgdorferi sensu lato. In addition, seasonal differences in B. burgdorferi s.l. prevalence were also investigated at a single site during 2015. Ixodes ricinus presence and activity were significantly higher in woodland edge habitat and during spring surveys. DNA of Borrelia burgdorferi s.l. was detected in 18.1% of nymphs collected across the 25 sites during 2013 and 2014 and two nymphs also tested positive for the newly emerging tick-borne pathogen B. miyamotoi. Borrelia burgdorferi s.l. prevalence at a single site surveyed in 2015 were found to be significantly higher during spring and summer than in autumn, with B. garinii and B. valaisiana most commonly detected. These data indicate that a range of habitats within an urban area in southern England support ticks and that urban Borrelia transmission cycles may exist in some of the urban green spaces included in this study. Sites surveyed were frequently used by humans for recreational activities, providing opportunity for exposure to Borrelia infected ticks in an urban/peri-urban space that might not be typically associated with tick-borne disease transmission.

Overwintering of the brown dog tick in residential properties in England-raising awareness.

PUBLIC Health England (PHE) previously reported a house infestation with the brown dog tick, Rhipicephalus sanguineus , in a residential property in Essex during 2014, following the importation of a dog from Spain (Hansford and others 2015). Despite repeated treatment of the property and continued application of tick treatments on dogs within the property, ticks are still being found and submitted to PHEs tick recording scheme (TRS). Repeated findings of these non-native ticks within the property suggest that a population has established and has been able to overwinter. This continues to represent a biting and potential disease risk to owners and pets within …

Detection of Dermacentor marginatus and a possible Rickettsia slovaca case in the United Kingdom – The risk of the visiting traveller

Ticks are widely recognised as a risk to human health and although numbers of travel-associated tickborne infections are low, they are likely underreported [1e3]. In the United Kingdom (UK), Public Health England (PHE) run a Tick Recording Scheme (TRS), and have previously published on the importation of a non-native tick species on a traveller [4]. This letter further highlights the importance of tick identification, in order to assist in the risk assessment of patients with suspected tickborne infections, not only among travellers, but also individuals who have recently been visited by travellers. In February 2014, the TRS received a tick specimen from an individual in southern England with no travel history. The tick was identified as a female Dermacentor marginatus (the ornate sheep tick) (Fig. 1). Normally distributed across Central and Western Europe, but not native to the UK, it is a vector of Rickettsia slovaca, causing tickborne lymphadenopathy (TIBOLA) and Dermacentor-borne necrosis-erythema-lymphadenopathy (DEBONEL). The patient was bitten on the back of the head (typical of this species), and reported a sore swollen lump at the bite site, swollen glands and flu-like symptoms, characteristic of rickettsial infection [5]. A serum sample was submitted to the Rare and Imported Pathogens Laboratory (RIPL) at PHE and the tick to the RIVM in the Netherlands for testing. Despite presentation with symptoms suggestive of infection, serum samples were negative for rickettsia. The

Distribution of the tick Dermacentor reticulatus in the United Kingdom

The recent implication of Dermacentor reticulatus (Ixodida: Ixodidae) in the transmission of canine babesiosis in the U.K. has highlighted the lack of accurate published data on its distribution in this country. This paper aims to collate and appraise historical data for D. reticulatus, to supplement such data with more recent surveillance data and to report on field sampling conducted during 2009–2016. These updated data facilitate better understanding of the current distribution of this tick in the U.K., which will better inform disease risk assessments. There appear to be four known regions of the U.K. in which D. reticulatus currently occurs, including western Wales, North and South Devon, and Essex. The majority of foci are located in coastal sand dunes and maritime grasslands, including grazing marsh. However, more recently the tick has been detected in urban greenspace in Essex. The emergence of this tick as a vector of babesiosis in the U.K. and its recent apparent spread in Essex into urban greenspace highlight the need for continued surveillance and for further research into its status as a vector of human and veterinary pathogens.

Rhipicephalus sanguineus importation into the UK: surveillance, risk, public health awareness and One Health response

As part of Public Health Englands assessment of vectorborne disease risk to public health in the UK, tick specimens are regularly submitted by veterinarians for identification via the Tick Surveillance Scheme. Recently, a number of these specimens have been identified as the brown dog tick, Rhipicephalus sanguineus. This species is non-endemic to the UK and presents a risk to both human and animal health due to its role in the transmission of various tickborne pathogens. Although current climatic conditions in the UK are unlikely to permit the survival of this species outdoors, indoor infestations can occur and this can present a risk of disease transmission within an infested property. This paper documents 40 importation events involving R sanguineus on recently travelled or imported dogs into the UK since 2012. It also provides details of the response following these detections in line with the One Health concept. With the increasing number of dogs travelling or being imported, it is likely that importation and infestation events in the UK will continue and may result in pathogen transmission. It is therefore important to raise awareness of this risk and share lessons learned to improve our prevention and response strategies to this emerging issue.

Potential risk posed by the importation of ticks into the UK on animals: records from the Tick Surveillance Scheme

In order to monitor important tick vectors in the UK, Public Health England’s Tick Surveillance Scheme (TSS) receives specimens from across the country for identification. In recent years, an increasing number of these specimens have been removed from animals with a recent history of travel outside the UK. This paper presents all data collated by the TSS on ticks entering the country on recently travelled or imported animals since surveillance commenced in 2005. Ten different tick species representing six different genera were identified, entering the UK from 15 different countries. Key themes appear to be emerging from the last 10 years of data, including canine travel from Cyprus and Spain being associated with Rhipicephalus sanguineus importation, and canine travel from France being associated with the importation of multiple tick species and canine illness. In addition, more unusual importation routes have been uncovered, such as the importation of Hyalomma lusitanicum on a dog. Some companion animal owners may not be fully aware of the risks associated with ticks, and may not seek advice from a veterinarian before travel or importing a pet. Promoting awareness of ticks and tickborne disease risk during and after travel or animal importation is needed and veterinarians play an importation role in disseminating this information to their clients.

Surveillance of British ticks: An overview of species records, host associations, and new records of Ixodes ricinus distribution

Public Health Englands passive Tick Surveillance Scheme (TSS) records the distribution, seasonality and host associations of ticks submitted from across the United Kingdom (UK), and helps to inform the UK government on emerging tick-borne disease risks. Here we summarise data collected through surveillance during 2010-2016, and compare with previous TSS data from 2005 to 2009, particularly in relation to the primary Lyme borreliosis vector Ixodes ricinus. 4173 records were submitted, constituting >14,000 ticks; 97% were endemic tick records (13,833 ticks of 11 species), with an additional 97 records of imported ticks (438 ticks of 17 species). Tick submissions were mainly from veterinary professionals (n = 1954; 46.8%) and members of the public and amateur entomologists (n = 1600; 38.3%), as well as from academic institutions (n = 249; 6.0%), wildlife groups (n = 239; 5.7%) and health professionals (n = 131; 3.1%). The most commonly reported hosts of endemic ticks were dogs (n = 1593; 39.1% of all records), humans (n = 835; 20.5%) and cats (n = 569; 14%). New host associations were recorded for a number of tick species. Ixodes ricinus was the most frequently recorded endemic tick species (n = 2413; 59.2% of all records), followed by I. hexagonus (n = 1355; 33.2%), I. canisuga (n = 132; 3.2%) and I. frontalis (n = 56; 1.4%), with other species each making up <1% total records. 81% of I. ricinus recorded from humans were nymphs, whereas 93.4% of I. ricinus from companion animals were adults. Recent TSS records of I. ricinus in the UK add a considerable amount of new presence data for this species, particularly in the southern regions of England, and confirm that this species is widespread across the UK. The scheme remains a valuable method of collecting continuous national distribution data on ticks from a variety of host species.