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Background Biting midges of the genus Culicoides (Diptera: Ceratopogonidae) are vectors of bluetongue virus (BTV), African horse sickness virus and Schmallenberg virus (SBV). Outbreaks of both BTV and SBV have affected large parts of Europe. The spread of these diseases depends largely on vector distribution and abundance. The aim of this analysis was to identify and quantify major spatial patterns and temporal trends in the distribution and seasonal variation of observed Culicoides abundance in nine countries in Europe. Methods We gathered existing Culicoides data from Spain, France, Germany, Switzerland, Austria, Denmark, Sweden, Norway and Poland. In total, 31,429 Culicoides trap collections were available from 904 ruminant farms across these countries between 2007 and 2013. Results The Obsoletus ensemble was distributed widely in Europe and accounted for 83% of all 8,842,998 Culicoides specimens in the dataset, with the highest mean monthly abundance recorded in France, Germany and southern Norway. The Pulicaris ensemble accounted for only 12% of the specimens and had a relatively southerly and easterly spatial distribution compared to the Obsoletus ensemble. Culicoides imicola Kieffer was only found in Spain and the southernmost part of France. There was a clear spatial trend in the accumulated annual abundance from southern to northern Europe, with the Obsoletus ensemble steadily increasing from 4000 per year in southern Europe to 500,000 in Scandinavia. The Pulicaris ensemble showed a very different pattern, with an increase in the accumulated annual abundance from 1600 in Spain, peaking at 41,000 in northern Germany and then decreasing again toward northern latitudes. For the two species ensembles and C. imicola, the season began between January and April, with later start dates and increasingly shorter vector seasons at more northerly latitudes. Conclusion We present the first maps of seasonal Culicoides abundance in large parts of Europe covering a gradient from southern Spain to northern Scandinavia. The identified temporal trends and spatial patterns are useful for planning the allocation of resources for international prevention and surveillance programmes in the European Union. Electronic supplementary material The online version of this article (10.1186/s13071-018-2706-y) contains supplementary material, which is available to authorized users.

International audience; Ticks are one of the principal arthropod vectors of human and animal infectious diseases. Whereas the prevalence of tick-borne encephalitis virus in ticks in Europe is well studied, there is less information available on the prevalence of the other tick-borne viruses (TBVs) existing worldwide. The aim of this study was to improve the epidemiological survey tools of TBVs by the development of an efficient high-throughput test to screen a wide range of viruses in ticks. In this study, we developed a new high-throughput virus-detection assay based on parallel real-time PCRs on a microfluidic system, and used it to perform a large scale epidemiological survey screening for the presence of 21 TBVs in 18 135 nymphs of Ixodes ricinus collected from five European countries. This extensive investigation has (i) evaluated the prevalence of four viruses present in the collected ticks, (ii) allowed the identification of viruses in regions where they were previously undetected. In conclusion, we have demonstrated the capabilities of this new screening method that allows the detection of numerous TBVs in a large number of ticks. This tool represents a powerful and rapid system for TBVs surveillance in Europe and could be easily customized to assess viral emergence.

SUMMARYHantaviruses are globally distributed and cause severe human disease.Puumalahantavirus (PUUV) is the most common species in Northern Europe, and the only hantavirus confirmed to circulate in Sweden, restricted to the northern regions of the country. In this study, we aimed to further add to the natural ecology of PUUV in Sweden by investigating prevalence, and spatial and host species infection patterns. Specifically, we wanted to ascertain whether PUUV was present in the natural reservoir, the bank vole (Myodes glareolus) further south than Dalälven river, in south-central Sweden, and whether PUUV can be detected in other rodent species in addition to the natural reservoir. In total, 559 animals were collected at Grimsö (59°43′N; 15°28′E), Sala (59°55′N; 16°36′E) and Bogesund (59°24′N; 18°14′E) in south-central Sweden between May 2013 and November 2014. PUUV ELISA-reactive antibodies were found both in 2013 (22/295) and in 2014 (18/264), and nine samples were confirmed as PUUV-specific by focus reduction neutralization test. Most of the PUUV-specific samples were from the natural host, the bank vole, but also from other rodent hosts, indicating viral spill-over. Finally, we showed that PUUV is present in more highly populated central Sweden.

Haematophagous mites were collected from the vent region and plumage of chickens in six hobby flocks of ornamental breeds in Sweden, one of which included turkeys. Soiled vent skin and feathers, dermatitis, hyperkeratosis, skin necroses and ulcers were observed in 12 necropsied birds from two of the flocks. The mites were identified as the northern fowl mite Ornithonyssus sylviarum (Mesostigmata: Macronyssidae). This was supported by sequence analysis of a 642-bp region in the mitochondrial cytochrome oxidase subunit 1 (COI) gene (COI) in mites collected from five flocks, which showed 97–99% sequence similarity to O. sylviarum by blast analysis. Pairwise sequence comparisons revealed nucleotide variations in the range of 0–2.8%, whereas amino acid sequences were highly conserved. This paper represents one of very few records of O. sylviarum in European poultry, and is the first to report COI sequence data for O. sylviarum from poultry in Europe. (Less)

Japanese encephalitis virus (JEV) is transmitted to humans from pigs or birds by mosquitoes. In this study, the association between urban pig keeping and mosquito vectors was analyzed. A total of 7, 419 mosquitoes were collected overnight in urban households with and without pigs in Can Tho City, Vietnam. The most prevalent vectors were Culex tritaeniorhynchus (36%), Cx. gelidus (24%), and Cx. quinquefasciatus (15%), which were present in all parts of the city. Pigs were associated with increased numbers of Cx. tritaeniorhynchus. Traps close to pigs had higher numbers of Cx. tritaeniorhynchus and Cx. gelidus than traps close to humans. Increased number of persons in the household was associated with increased numbers of Cx. quinquefasciatus. We demonstrate that JEV vector species are present at urban households with and without pigs, and show that keeping pigs in an urban area increase the number of mosquitoes competent as vectors for JEV.

Biting midges of the genus Culicoides (Diptera: Ceratopogonidae) are insect vectors of economically important veterinary diseases such as African horse sickness virus and bluetongue virus. However, the identification of Culicoides based on morphological features is difficult. The sequencing of mitochondrial cytochrome oxidase subunit I (COI), referred to as DNA barcoding, has been proposed as a tool for rapid identification to species. Hence, a study was undertaken to establish DNA barcodes for all morphologically determined Culicoides species in Swedish collections. In total, 237 specimens of Culicoides representing 37 morphologically distinct species were used. The barcoding generated 37 supported clusters, 31 of which were in agreement with the morphological determination. However, two pairs of closely related species could not be separated using the DNA barcode approach. Moreover, Culicoides obsoletus Meigen and Culicoides newsteadi Austen showed relatively deep intraspecific divergence (more than 10 times the average), which led to the creation of two cryptic species within each of C. obsoletus and C. newsteadi. The use of COI barcodes as a tool for the species identification of biting midges can differentiate 95% of species studied. Identification of some closely related species should employ a less conserved region, such as a ribosomal internal transcribed spacer.

The outbreak of bluetongue (BT) in northern Europe 2006 initiated the monitoring of vectors, biting midges of the genus Culicoides in Sweden. In order to determine the diversity, distribution and seasonal dynamics of Culicoides, weekly collections were made during 2008 and during March-December 2009 using the Ondestepoort Veterinary Institute black light trap. Twenty sampling sites were selected in 12 provinces. In total of 30,704 Culicoides were collected in 2008 and 32,252 in 2009. The most abundant species were the potential vectors of BTV Culicoides obsoletus/C. scoticus that comprised of 77% of the total catches. Other biting midges collected were Culicoides impunctatus (9%), Culicoides grisescens (3%), Culicoides punctatus (2%), Culicoides chiopterus (2%) and Culicoides pulicaris (2%). Culicoides obsoletus/C. scoticus were most abundant during May-June and August-September. The majority of the species were active from March to November in 2008 and April to October in 2009. Species considered as potential vectors of bluetongue virus (BTV) occurred as far north as latitude 65°N (Kalix).

Infection with the zoonotic bacterium Erysipelothrix rhusiopathiae causes severe disease outbreaks (erysipelas) in poultry flocks. As this bacterium has been isolated from the poultry red mite (Dermanyssus gallinae), this parasite has been suggested as a possible means of transmission of E. rhusiopathiae on and between poultry farms. To further elucidate the capacity of the mite as a reservoir, we analysed and compared 56 bacterial isolates from laying hens and nine isolates from mites by pulsed-field gel electrophoresis (PFGE), using the restriction enzyme SmaI. The isolates originated from one outbreak in a laying hen flock housed in an indoor litter-based aviary system. Except for two isolates, a homogeneous banding pattern was obtained from all isolates analysed, suggesting that a single strain was the cause of the outbreak. Another finding was that isolates from individual hens could exhibit slightly different PFGE patterns. Mites collected from the same house at the end of the production period of the following flock were negative for the presence of E. rhusiopathiae. An increasing number of erysipelas outbreaks as well as escalating problems with D. gallinae are expected in other European countries related to the forthcoming changes in housing systems for laying hens. Consequently, further studies are needed to investigate the importance of erysipelas in poultry and the importance of D. gallinae in the transmission of E. rhusiopathiae.

Erysipelothrix rhusiopathiae is the causative agent of erysipelas in mammals and birds, especially pigs and poultry. In order to investigate the suitability of different subtyping methods for genetic and phenotypic similarities among Swedish isolates of the organism, 45 isolates from poultry (n=23), pigs (n=17), emus (n=2) and the poultry red mite Dermanyssus gallinae (n=3) were investigated by serotyping, pulsed-field gel electrophoresis (PFGE) and antimicrobial susceptibility testing. Sequence analysis of the 16S rRNA gene was performed on eleven isolates from nine animal species. The results indicated a random scattering of serotypes throughout the dendrogram based on PFGE banding patterns following SmaI digestion. In three cases, isolates with an identical PFGE pattern were of differing serotypes. No differentiation into subgroups by antimicrobial susceptibility testing by broth microdilution was possible as results were similar for all isolates. The Minimum Inhibitory Concentrations for most antimicrobials, including penicillin and oxytetracycline, were low. The 16S rRNA gene sequences (1443 nts) from eight of eleven selected isolates of Erysipelothrix spp. were identical to that of the type strain E. rhusiopathiae ATCC 19414(T). The other three isolates differed from the type strain by two or three nucleotides. While this method may be useful for identification of Erysipelothrix spp., it is unsuitable for epidemiological investigations. Similarities in PFGE banding patterns between isolates from chickens and mites supported the hypothesis that D. gallinae may act as a reservoir and vector for E. rhusiopathiae. Further PFGE studies on E. rhusiopathiae isolates are appropriate to investigate the epidemiology of poultry erysipelas.

We investigated the presence of the poultry red mite or the chicken mite, Dermanyssus gallinae De Geer, Acari: Dermanyssidae, in wild bird populations in four different geographical regions of Sweden. The mites identified as D. gallinae were compared genetically with D. gallinae from egg-producing poultry farms in the same regions. The small subunit (SSU) gene, the 5.8S ribosomal RNA (rRNA) gene and the two internal transcribed spacers (ITS) of the rRNA genes were used in the genetic analysis. All D. gallinae mites had identical SSU rRNA, 5.8S rRNA and ITS2 sequences independent of their origin. By contrast, we identified significant differences in the ITS1 sequences. Based on the differences in the ITS1 sequences, the mites could be divided into two genotypes, of wild and domesticated origin, with no variation within the groups. These results imply that wild bird populations are of low importance, if any, as natural reservoirs of D. gallinae in these four geographical regions of Sweden.

Background The epidemiology of the zoonotic tick-transmitted parasite Babesia spp. and its occurrence in wild reservoir hosts in Sweden is unclear. In European deer, several parasite species, including Babesia capreoli and the zoonotic B. venatorum and B. divergens has been reported previously. The European roe deer, Capreolus capreolus, is an important and common part of the indigenous fauna in Europe, as well as an important host for Ixodes ricinus ticks, the vector of several Babesia spp. in Europe. Here, we aimed to investigate the occurrence of Babesia spp. in roe deer in Sweden. Findings Roe deer (n = 77) were caught and sampled for blood. Babesia spp. was detected with a PCR assay targeting the 18S rRNA gene. The prevalence of Babesia spp. was 52 %, and two species were detected; B. capreoli and B. venatorum in 44 and 7.8 % of the individuals, respectively. Infection occurred both in summer and winter. Conclusions We showed that roe deer in Sweden, close to the edge of their northern inland distributional range, are infected with Babesia spp. The occurrence of B. venatorum in roe deer imply that it is established in Sweden and the zoonotic implication of this finding should be regarded to a greater extent in future.

The face fly (Musca autumnalis De Geer) and horn fly (Haematobia irritans ([L.])) were studied at the southern edge of the face fly's North American range, examining southern California geographic distribution, seasonal activity on cattle and in dung, and diapause. Face flies were common only at Pomona (34°03'N, 117°48'W). Other irrigated pastures, even those only slightly inland from Pomona, were probably too warm for face flies, due to a steep west (cooler) to east (warmer) temperature gradient. Horn flies were abundant at all sites. Adult densities on cattle, adults emerging from dung pats, and prevalence of fly-positive pats were assessed for both fly species throughout a year at Pomona. Summer adult horn fly densities of 500-2,000 flies per cow, or face fly densities of 3-10 flies per face, were common. Summer prevalence of face fly-positive pats and horn fly-positive pats was about 20-40% and 30-70%, respectively. Face fly adults diapaused from late October until late March and early April. Horn flies probably diapaused as pupae from late October or early November to early-mid March, although some emerged in winter. Experimental cohorts of October-emerging adult face flies were held in a representative overwintering site. They exhibited hypertrophied fat body and undeveloped oocytes, which are characteristics of diapause, and survived until the following spring. The dominant diapause cues in face and horn flies are probably photoperiod and temperature. Despite warm winter temperatures that would permit activity of both species, and despite relatively long winter day lengths, face flies and most horn flies still diapaused at this latitude.

The effect of neem oil (azadirachtin), originating from the tree Azadirachta indica, was investigated as a potential compound to control the poultry red mite, Dermanyssus gallinae. In vitro tests were performed to determine the most appropriate formulation of neem extracts and concentration of the substance to be used. Cardboard traps containing 20% neem oil were placed at the mites' aggregation sites, out of reach of the hens, in a floor system for layers containing approximately 2400 birds. Treated traps were replaced every week for 4 weeks. Throughout the study, the parasite population was monitored by collections of mites with untreated plastic traps. A 92% reduction of D. gallinae was recorded.

International audience; Due to increased travel, climatic, and environmental changes, the incidence of tick-borne disease in both humans and animals is increasing throughout Europe. Therefore, extended surveillance tools are desirable. To accurately screen tick-borne pathogens (TBPs), a large scale epidemiological study was conducted on 7050 Ixodes ricinus nymphs collected from France, Denmark, and the Netherlands using a powerful new high-throughput approach. This advanced methodology permitted the simultaneous detection of 25 bacterial, and 12 parasitic species (including; Borrelia, Anaplasma, Ehrlichia, Rickettsia, Bartonella, Candidatus Neoehrlichia, Coxiella, Francisella, Babesia, and Theileria genus) across 94 samples. We successfully determined the prevalence of expected (Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum, Rickettsia helvetica, Candidatus Neoehrlichia mikurensis, Babesia divergens, Babesia venatorum), unexpected (Borrelia miyamotoi), and rare (Bartonella henselae) pathogens in the three European countries. Moreover we detected Borrelia spielmanii, Borrelia miyamotoi, Babesia divergens, and Babesia venatorum for the first time in Danish ticks. This surveillance method represents a major improvement in epidemiological studies, able to facilitate comprehensive testing of TBPs, and which can also be customized to monitor emerging diseases.

Traps made by rectangular pieces of 3 mm thick corrugated cardboard of four different sizes, 200 by 140 (A), 140 by 100 (B), 100 by 70 (C), and 200 by 40 mm (D), were evaluated as a sampling device for the chicken mite, Dermanyssus gallinae (De Geer). Mites were trapped during 2, 4, 6, 8, and 10 d, respectively, in a poultry house heavily infested with the parasite. Significantly greater numbers of mites were collected by trap B. Additionally, significantly more mites were collected during the sampling periods 6-10 d than by 2 and 4 d. However, with regard to trap size and sampling period, trap C, used for 2 d, collected significantly more mites per day and trap area than any of the other traps. Therefore, such a trap was suggested for monitoring population trends of chicken mites in poultry houses. The larger traps contained significantly higher numbers of mites per trap and may therefore be feasible to use in alternative, nonchemical control programs. Optimum sample size, or number of traps required to monitor population trends of D. gallinae, was also calculated. At a relative variability of 20%, and at densities of 2,000-20,000 mites per trap, approximately 11-16 of trap B and 11-19 of trap C would be adequate to monitor mites.

Embryos of the primary screwworm, Cochliomyia hominivorax (Coquerel), were successfully permeabilized for use in subsequent cryopreservation studies. Mortality was greater for eggs incubated for

Summer mastitis is an acute suppurative bacterial infection of the udder in heifers and dry cows. To ascertain the possible role of flies in the transmission of the disease, experimental exposures of recipient heifers to Hydrotaea irritans previously exposed to bacteria were carried out. Flies were allowed to feed on secretions from clinical cases of summer mastitis. The pathogens present were the bacteria Staphylococcus aureus, Streptococcus dysgalactiae, Actinomyces pyogenes, Stuart-Schwan cocci, Peptococcus indolicus, Fusobacterium necrophorum and Bacterioides species. The teats of eight heifers were exposed to flies with verified pathogen content. Two teats of each animal were deliberately damaged before fly exposure. One teat was cut, another pricked with insect needles to mimic insect bites. Two of the heifers developed summer mastiris in the quarters where teats had been cut. The bacterial species isolated from these quarters corresponded to those that had previously been fed to the flies. For the first time, it is now demonstrated that H. irritans is capable of transmitting summer mastitis pathogens and so causing summer mastitis in recipient heifers. Lesions on the teat orifice may be a predisposing factor in the development of the disease.

Investigations of host preferences in haematophagous insects, including Culicoides biting midges (Diptera: Ceratopogonidae), are critical in order to assess transmission routes of vector-borne diseases. In this study, we collected and morphologically identified 164 blood-engorged Culicoides females caught in both light traps and permanent 12-m high suction traps during 2008-2010 in Sweden. Molecular analysis of the mitochondrial cytochrome c oxidase subunit I (COI) gene in the biting midges was performed to verify species classification, discern phylogenetic relationships and uncover possible cryptic species. Bloodmeal analysis using universal vertebrate cytochrome b primers revealed a clear distinction in host selection between mammalophilic and ornithophilic Culicoides species. Host sequences found matches in horse (n = 59), sheep (n = 39), cattle (n = 26), Eurasian elk (n = 1) and 10 different bird species (n = 18). We identified 15 Culicoides species previously recorded in Scandinavia and four additional species haplotypes that were distinctly different from the described species. All ornithophilic individuals (n = 23) were caught exclusively in the suction traps, as were, interestingly, almost all mammalophilic species (n = 41), indicating that many biting midge species may be able to cover long distances after completing a bloodmeal. These results add new information on the composition of Culicoides species and their host preferences and their potential long-distance dispersal while blood-engorged.

Diapausing face flies, Musca autumnalis (De Geer), are characterized by the presence of hypertrophied fat bodies (HFB) and arrested ovarian development. A total of 1752 face flies were caught around cattle in south-central Sweden during the last 5 weeks of the grazing season, in August-September. Females in this material (1139) were examined in search of HFB and to determine their reproductive status. It was assumed a priori that gonoactive flies would not undergo diapause. Flies were also dissected in search of the nematodes Parafilaria bovicola (Tubangui), Thelazia spp. and Heterotylenchus autumnalis (Nickle). Only females were found to be infected, of which 0.6% contained P. bovicola, 0.6% Thelazia spp. and 1.4% H. autumnalis. Both gonoactive and nongonoactive flies were infected with P. bovicola and Thelazia spp. Only nongonoactive Thelazia-infected flies had HFB, which is suggestive of flies able to overwinter. In the Heterotylenchus-infected flies with HFBs, arrested development (hypobiosis) of the nematode was recorded.

In light of the emergence of bluetongue in northern Europe, populations of Culicoides species were monitored in 2007-2008 by means of Onderstepoort blacklight suction traps operating at livestock farms in Sweden. The location of the 22 sampling sites ranged from about latitude 55°N to about 68°N. A total of 61,669 male and female Culicoides were captured, of which, 52,319 were trapped outside the farms and 9,350 in byres or livestock sheds. Thirty-three Culicoides species were recorded, of which, 30 were new to Sweden. The species and their relative abundance and spatial distribution on sites are presented. Two species incriminated as vectors of bluetongue virus, viz. Culicoides obsoletus (about 38%) and Culicoides scoticus (about 36%), were predominant and common in the environment of livestock farms practically all over the Swedish mainland, penetrating far north to at least 65°N. The two species were also recorded from the island of Gotland. Culicoides pulicaris, another potential vector species, accounted for about 9% of all Culicoides captured.

The vector potential of the poultry red mite, Dermanyssus gallinae De Geer (Acari: Dermanyssidae), in relation to chicken erysipelas was investigated under experimental conditions. Chickens were inoculated intramuscularly with the bacterium Erysipelothrix rhusiopathiae, and mites were allowed to feed on the inoculated chickens for 5 days. After 20 days of starvation, the mites were allowed to feed on healthy chickens to enable transmission of bacteria. Blood samples were collected from the birds and analysed for the presence of E. rhusiopathiae, and ELISA tests were performed for seropositivity. The internal presence of E. rhusiopathiae in the mites after feeding of inoculated birds was also investigated. It could not be demonstrated that mites take up and transmit E. rhusiopathiae under the experimental conditions described. However, since there are case reports as well as other in vitro studies indicating the potential of D. gallinae to act as a reservoir and potential vector for infections agents, we cannot exclude the possibility that the red poultry mite transmits E. rhusiopathiae between chickens under field conditions.

The spread of human leishmaniasis has prompted the scientific community to study dogs as reservoirs for Leishmania infantum. Canine leishmaniasis (CanL) is widespread in the Mediterranean area with a prevalence of up to 50%. The first step toward controlling the disease is to monitor its distribution, mainly in stray dogs. The validity of a recombinant K39 (rK39) dipstick test,a commercially available for the serodiagnosis of human leishmaniasis, was evaluated using sera from 165 dogs selected on the basis of positive or negative lymph node smears at parasitological examination. The results were compared with the indirect fluorescent antibody test (IFAT) (cutoff 1:80). Sera from a group of dogs with other diagnosed diseases but negative for leishmaniasis were also tested to evaluate any cross-reactivity. Various procedures were used for testing whole blood samples. The relative specificity of the rK39 dipstick and IFAT was 100% (97 of 97) and 98.97% (96 of 97), whereas the relative sensitivity was 97.06% (66 of 68) and 98.53% (67 of 68), respectively. The results of the dipstick and IFAT corresponded except for 2 sera (k = 0.987). This data confirm the usefulness of rK39 antigen for diagnosing CanL both in symptomatic and asymptomatic dogs. The rK39 dipstick proved to be a rapid, sensitive, and specific test that may be very useful in the field for large-scale screening and also in veterinary practice, requiring minimal equipment and operator expertise.

In the perspective to reduce the use of antiparasitic drugs, any interaction between the processes that control the development of parasite eggs into infective larval stages (L3) in dung and the activities of different dung-breeding organisms becomes of interest. The objective of the present study was to determine whether dung beetle activity affected the development of parasite larvae in cattle dung. Faeces containing eggs of parasites (predominantly Cooperia spp.) were pooled according to high (250-600 epg) or low (approx. 100 epg) egg counts. Experimental dung pats were formed for each category of faeces and to half of these pats, dung beetles (20 Aphodius rufipes, 20 A. scybalarius syn. rufus) were added and kept for 12 days at 21 degrees C (+/-1 degrees C) and 90% RH (+/-5% RH). Beetles were then removed and the pats were divided in two where half the pat was incubated for an additional 12 days at 21 degrees C (+/-1 degrees C) and 90% RH (+/-5% RH) and the other half was immediately analysed. A greater number of L3 were recovered from the dung subjected to beetle activity compared with control dung (P

Erysipelas is a bacterial disease caused by Erysipelothrix rhusiopathiae, which may infect swine as well as several other species of mammals and birds, including domestic fowl. In poultry, erysipelas may cause sudden high mortality due to septicemia. This communication describes the first isolation of E. rhusiopathiae from the haematophagous poultry red mite, Dermanyssus gallinae DeGeer (Acari: Dermanyssidae), that was collected on three farms where hen erysipelas was diagnosed. The bacteria were isolated from the integument as well as from the interior of the mites. Serotypes 1a and 1b of E. rhusiopathiae found in the mites corresponded with those isolated from the diseased birds. These findings imply that D. gallinae is a potential vector of E. rhusiopathiae. The current lack of effective measures to control D. gallinae causes recurring mite problems in poultry facilities once afflicted by this parasite. Consequently, mites containing E. rhusiopathiae may act as reservoir hosts of this bacterium, allowing it to persist in the poultry house between flock cycles as a source of infection for the replacement pullets. The zoonotic potentials of both E. rhusiopathiae and D. gallinae should also be considered.

In Sweden, the poultry red mite, Dermanyssus gallinae, is the only haematophagous mite of poultry. After obtaining a blood meal the parasite spends most of its life off the host aggregated in cracks and crevices where mating and reproduction occur. Cardboard traps ( 1000 mm ×40 mm ×3 mm ; 160 mm ×140 mm ×3 mm and 100 mm ×70 mm ×3 mm) containing 2% metriphonate were placed where mites gathered, out of reach of the hens, in two different types of multi-tiered floor systems for layers. In two separate trials, treated traps were replaced every second day for 2 weeks and every week for 8 weeks. In the 2-week trial the whole floor system was treated while in the 8-week trial six of 12 existing compartments studied were treated. The untreated compartments were used as controls. Throughout the study, the parasite populations were monitored by collections of mites with untreated cardboard traps ( 100 mm ×70 mm ×3 mm). A 95% reduction of mites was recorded in the 8-week trial whereas a 99% reduction of mites was recorded in the 2-week trial. The placement of treated traps near mite aggregation sites was essential for satisfactory control.

The effect of permethrin impregnated plastic strips (Die No Mite Strips) was evaluated on Dermanyssus gallinae populations in aviary systems for layers in Sweden. Two application strategies of the strips were tested: (A) attached in the housing system, allowing the birds to rub against the strips and thereby get the acaricide released onto their plumage, and (B) attached out of reach of the hens, at two different sites (perches and egg-belt lids) of the inner surfaces of the system, where the mites sheltered during the day. On two farms with 2030 (A) and 3384 (B) hens, and existing mite populations, strips were mounted for 20 and 10 weeks, respectively, and mite numbers were monitored by traps. With application A an overall mite reduction of 53% was observed, while with B the mean mite numbers decreased by 39% at the perches and 92% at the egg-belt lid. The strips were originally designed for caged hens afflicted by ectoparasites that stay on the host for most of their life cycle. However, since D. gallinae spends most of its time off the host, it was not possible to control the parasite with application A. Resistance tests performed on mites from both treated and control compartments where application A was used showed no indication of resistance to permethrin, while 95% of the mites survived a 48 h exposure to the compound where application B was performed. Thus, permethrin resistant mites appeared to be the main reason for the failure to control D. gallinae with application B.

In light of the emergence of bluetongue in Northern Europe, populations of Culicoides species were monitored in and around several Swedish livestock farms (surveillance in 2007 and 2008). The position of the sampling sites ranged from about latitude 55° N to about 68° N. Thirty-three Culicoides species were recorded, of which 30 were new to Sweden. The species recorded, and their relative abundance and spatial distribution on sites are detailed. Species incriminated as vectors of bluetongue virus were predominant.

Experimental infections were produced with the host-specific nematode Heterotylenchus autumnalis, which sterilizes its host, the face fly (Musca autumnalis). The high infection rate achieved (means = 82.5%) was similar for male and female flies. The pupal emergence rate was significantly lower for fly larvae exposed to the nematodes than for unexposed controls. Heterotylenchus-exposed flies had a sex ratio skewed in favor of males. This indicates that in addition to sterilization, H. autumnalis has other deleterious effects on its host. Heterotylenchus autumnalis is therefore a candidate for use as a potential biological control agent of the face fly.

This review covers the geographic distribution and host relationships of the tick species in Sweden. Ixodes uriae White, I. caledonicus Nuttall, I. unicavatus Neumann, I. arboricola Schulze & Schlottke, and I. lividus Koch are ornithophagous species. I. trianguliceps Birula, I. canisuga Johnston, I. hexagonus Leach, and Argas vespertilionis (Latreille) are mammalophagous. I. ricinus (L.) and Haemaphysails punctata Canestrini & Fanzago feed on both birds and mammals. All these tick species may be considered to be permanently present in Sweden. I. persulcatus Schulze, Hyalomma marginatum Koch, and the brown dog tick, Rhipicephalus satiguineus (Latreille), may be regarded as not indigenous to Sweden although they may be regularly introduced by spring-migrating birds or imported dogs, respectively. The first European record of the American dog tick, Dermacentor variabilis (Say), is reported. There are several records of Hyalomma aegyptium (L.) from imported tortoises in Sweden. Excluding other ticks imported on exotic pets and zoo animals, another 13 tick species are listed that may occur, at least occasionally, in Sweden. Because of its wide geographic distribution, great abundance, and wide host range, I. ricinus is medically the most important arthropod in northern Europe. I. ricinus is common in southern and south-central Sweden and along the coast of northern Sweden and has been recorded from 29 mammal species, 56 bird species, and two species of lizards in Sweden alone. The potential introduction to Sweden of exotic pathogens with infected ticks (e.g., I. persulcatus and H. marginatum on birds or Dermacentor spp. and R. sanguineus on mammals) is evident.

Larvae of Cephenemyia (Latreille 1818), the moose bot fly (Diptera; Oestridae) are parasites of the nose and pharynx in cervidae. In Europe 4 species of Cephenemyia are reported, C. trompe (Modeer 1786) in reindeer (Rangifer tarandus tarandus L), C. stimulator (Clark 1815) in roe deer (Capreolus capreolus L), C. auribarbis (Meigen 1824) in red deer (Cervus elaphus L) and fallow deer (Dama dama L), and C. ulrichii, Brauer 1862, in moose (Alces alces L) (Zumpt 1965, Grunin 1966). Of these, C. trompe is known from northern Scandinavia (Zumpt 1965, Grunin 1966), C. stimulator is reported from Denmark (Christiansen 1935), and C. ulrichii from Finland (Frey 1914, Brander 1963, Mikkola et al 1982). This is the first report on C. ulrichii larvae found in Sweden.