Circulation of four Anaplasma phagocytophilum ecotypes in Europe

Detection of Anaplasma sp. phylogenetically related to A. phagocytophilum in a free-living bird in Brazil

Abstract Wild animals play an important role in carrying vectors that may potentially transmit pathogens. Several reports highlighted the participation of wild animals on the Anaplasma phagocytophilum cycle, including as hosts of the agent. The aim of this study was to report the molecular detection of an agent phylogenetically related to A. phagocytophilum isolated from a wild bird in the Midwest of the state of Paraná, Brazil. Fifteen blood samples were collected from eleven different bird species in the Guarapuava region. One sample collected from a Penelope obscura bird was positive in nested PCR targeting the 16S rRNA gene of Anaplasma spp. The phylogenetic tree based on the Maximum Likelihood analysis showed that the sequence obtained was placed in the same clade with A. phagocytophilum isolated from domestic cats in Brazil. The present study reports the first molecular detection of a phylogenetically related A. phagocytophilum bacterium in a bird from Paraná State.

Host specificity, pathogen exposure, and superinfections impact the distribution of Anaplasma phagocytophilum genotypes in ticks, roe deer, and livestock in a fragmented agricultural landscape

Anaplasma phagocytophilum is a bacterial pathogen mainly transmitted by Ixodes ricinus ticks in Europe. It infects wild mammals, livestock, and, occasionally, humans. Roe deer are considered to be the major reservoir, but the genotypes they carry differ from those that are found in livestock and humans. Here, we investigated whether roe deer were the main source of the A. phagocytophilum genotypes circulating in questing I. ricinus nymphs in a fragmented agricultural landscape in France. First, we assessed pathogen prevalence in 1837 I. ricinus nymphs (sampled along georeferenced transects) and 79 roe deer. Prevalence was dramatically different between ticks and roe deer: 1.9% versus 76%, respectively. Second, using high-throughput amplicon sequencing, we characterized the diversity of the A. phagocytophilum genotypes found in 22 infected ticks and 60 infected roe deer; the aim was to determine the frequency of co-infections. Only 22.7% of infected ticks carried genotypes associated with roe deer. This finding fits with others suggesting that cattle density is the major factor explaining infected tick density. To explore epidemiological scenarios capable of explaining these patterns, we constructed compartmental models that focused on how A. phagocytophilum exposure and infection dynamics affected pathogen prevalence in roe deer. At the exposure levels predicted by the results of this study and the literature, the high prevalence in roe deer was only seen in the model in which superinfections could occur during all infection phases and when the probability of infection post exposure was above 0.43. We then interpreted these results from the perspective of livestock and human health.

Detecting and characterizing mixed infections with genetic variants of Anaplasma phagocytophilum in roe deer (Capreolus capreolus) by developing an ankA cluster-specific nested PCR

Background

Anaplasma phagocytophilum is a tick-transmitted Gram-negative obligate intracellular bacterium able to infect a wide variety of wild and domestic animals worldwide. Based on the genetic diversity observed with different molecular markers, several host-specific lineages have been identified. Roe deer is one of the most important reservoirs of this bacterium and hosts different genetic groups sometimes found on domestic animals. We therefore developed an ankA cluster-specific nested PCR (nPCR) to evaluate the prevalence of the three different ankA genetic groups described in roe deer (clusters II, III and IV) at three locations in France and the level of co-infections.

Results

The specificity of the three nPCRs was assessed by partially sequencing 35 amplicons of ankA genes obtained from the different nested PCRs. All three genetic lineages were detected in roe deer from all three geographical locations. Of the infected deer population, 60.7% were co-infected by two or three different genetic variants. Co-infections varied from 42.9 to 70.6% of the infected population depending on the local infection prevalences (from 33.3 to 73.9%). All types of mixed infections occurred, suggesting the absence of a strict variant exclusion by another variant.

Conclusions

Mixed infections by two or three genetic variants of A. phagocytopilum are a common feature in roe deer. Genetic variants (cluster IV) also found in domestic ruminants (cattle and sheep) were present in all the roe deer populations analyzed, suggesting a shared epidemiological cycle.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-017-2316-0) contains supplementary material, which is available to authorized users.

Prevalence and genetic variability of Anaplasma phagocytophilum in wild rodents from the Italian alps

Background

Human granulocytic anaplasmosis is a zoonotic bacterial disease with increasing relevance for public health in Europe. The understanding of its sylvatic cycle and identification of competent reservoir hosts are essential for improving disease risk models and planning preventative measures.

Results

In 2012 we collected single ear biopsy punches from 964 live-trapped rodents in the Province of Trento, Italy. Genetic screening for Anaplasma phagocytophilum (AP) was carried out by PCR amplification of a fragment of the 16S rRNA gene. Fifty-two (5.4%) samples tested positive: 49/245 (20%) from the bank vole (Myodes glareolus) and 3/685 (0.4%) samples collected from the yellow-necked mouse (Apodemus flavicollis). From these 52 positive samples, we generated 38 groEL and 39 msp4 sequences. Phylogenetic analysis confirmed the existence of a distinct rodent strain of AP.

Conclusions

Our results confirm the circulation of a specific strain of AP in rodents in our study area; moreover, they provide further evidence of the marginal role of A. flavicollis compared to M. glareolus as a reservoir host for this pathogen.

Tick infestation of small mammals in an English woodland

Tick infestations on small mammals were studied from April to November, 2010, in deciduous woodland in southern England in order to determine whether co-infestations with tick stages occurred on small mammals, a key requirement for endemic transmission of tick-borne encephalitis virus (TBEV). A total of 217 small mammals was trapped over 1,760 trap nights. Yellow-necked mice (Apodemus flavicollis) made up the majority (52.5%) of animals, followed by wood mice (A. sylvaticus) 35.5% and bank voles (Myodes glareolus) 12%. A total of 970 ticks was collected from 169 infested animals; 96% of ticks were Ixodes ricinus and 3% I. trianguliceps. Over 98% of ticks were larval stages. Mean infestation intensities of I. ricinus were significantly higher on A. flavicollis (6.53 ± 0.67) than on A. sylvaticus (4.96 ± 0.92) and M. glareolus (3.25 ± 0.53). Infestations with I. ricinus were significantly higher in August than in any other month. Co-infestations with I. ricinus nymphs and larvae were observed on six (3.6%) infested individuals, and fifteen small mammals (8.9%) supported I. ricinus - I. trianguliceps co-infestations. This work contributes further to our understanding of European small mammal hosts that maintain tick populations and their associated pathogens, and indicates that co-infestation of larvae and nymph ticks does occur in lowland UK. The possible implications for transmission of tick-borne encephalitis virus between UK ticks and small mammals are discussed.

Melting pot of tick-borne zoonoses: the European hedgehog contributes to the maintenance of various tick-borne diseases in natural cycles urban and suburban areas

Background

European hedgehogs (Erinaceus europaeus) are urban dwellers and host both Ixodes ricinus and Ixodes hexagonus. These ticks transmit several zoonotic pathogens like Borrelia burgdorferi (sensu lato), Anaplasma phagocytophilum, Rickettsia helvetica, Borrelia miyamotoi and “Candidatus Neoehrlichia mikurensis”. It is unclear to what extent hedgehogs in (sub) urban areas contribute to the presence of infected ticks in these areas, which subsequently pose a risk for acquiring a tick-borne disease. Therefore, it is important to investigate to what extent hedgehogs contribute to the enzootic cycle of these tick-borne pathogens, and to shed more light at the mechanisms of the transmission cycles involving hedgehogs and both ixodid tick species.

Methods

Engorged ticks from hedgehogs were collected from (sub) urban areas via rehabilitating centres in Belgium. Ticks were screened individually for presence of Borrelia burgdorferi (sensu lato), Borrelia miyamotoi, Anaplasma phagocytophilum, Rickettsia helvetica and “Candidatus Neoehrlichia mikurensis” using PCR-based methods. Infection rates of the different pathogens in ticks were calculated and compared to infection rates in questing ticks.

Results

Both Ixodes hexagonus (n = 1132) and Ixodes ricinus (n = 73) of all life stages were found on the 54 investigated hedgehogs. Only a few hedgehogs carried most of the ticks, with 6 of the 54 hedgehogs carrying more than half of all ticks (624/1205). Borrelia miyamotoi, A. phagocytophilum, R. helvetica and B. burgdorferi genospecies (Borrelia afzelii, Borrelia bavariensis and Borrelia spielmanii) were detected in both I. hexagonus and I. ricinus. Anaplasma phagocytophilum, R. helvetica, B. afzelii, B. bavariensis and B. spielmanii were found significantly more in engorged ticks in comparison to questing I. ricinus.

Conclusions

European hedgehogs seem to contribute to the spread and transmission of tick-borne pathogens in urban areas. The relatively high prevalence of B. bavariensis, B. spielmanii, B. afzelii, A. phagocytophilum and R. helvetica in engorged ticks suggests that hedgehogs contribute to their enzootic cycles in (sub) urban areas. The extent to which hedgehogs can independently maintain these agents in natural cycles, and the role of other hosts (rodents and birds) remain to be investigated.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-017-2065-0) contains supplementary material, which is available to authorized users.

A Borrelia afzelii Infection Increases Larval Tick Burden on Myodes glareolus (Rodentia: Cricetidae) and Nymphal Body Weight of Ixodes ricinus (Acari: Ixodidae)

Several microorganisms have been shown to manipulate their host or vector to enhance their own transmission. Here we examined whether an infection with Borrelia afzelii affects its transmission between its bank vole (Myodes glareolus, Schreber, 1780) host and tick vector. Captive-bred bank voles were inoculated with B. afzelii or control medium, after which host preference of Ixodes ricinus L. nymphs was determined in a Y-tube olfactometer. Thereafter, infected and uninfected bank voles were placed in a semifield arena containing questing larvae to measure larval tick attachment. Engorged larvae were collected from these bank voles, molted into nymphs, weighed, and analyzed for infection by PCR.Nymphs were attracted to the odors of a bank vole compared to ambient air and preferred the odors of an infected bank vole over that of an uninfected bank vole. In the semifield arena, infected male bank voles had greater larval tick burdens then uninfected males, while similar larval tick burdens were observed on females regardless of infection status. Nymphal ticks that acquired a B. afzelii infection had higher body weight than nymphs that did not acquire an infection regardless of the infection status of the vole. These results show that a B. afzelii infection in bank voles increases larval tick burden and that a B. afzelii infection in larvae increases nymphal body weight. This finding provides novel ecological insights into the enzootic cycle of B. afzelii.

Fatal human anaplasmosis associated with macrophage activation syndrome in Greece and the Public Health response

Human granulocytic anaplasmosis (HGA) is a tick-borne disease caused by Anaplasma phagocytophilum that has the potential to spread in new geographical areas. The first fatal case of HGA in Greece is presented. Fever of unknown origin, renal and respiratory insufficiency and development of macrophage activation syndrome characterized the clinical presentation. Amplification and sequencing of a fragment of the groEL gene revealed the presence of A. phagocytophilum. The epidemiological and clinical features were collected during an epidemiological investigation. Public health measures were instituted by the Hellenic Centre for Disease Control and Prevention. The Public Health intervention required the collaboration of epidemiologists, veterinarians and microbiologists. Emphasis was given to communication activities and misconceptions concerning canines and their role in the disease. The emergence of human anaplasmosis in a new geographical area highlights the importance of disease awareness and of the need for continued support for tick and tick-borne disease surveillance networks.

Seasonal infestation of birds with immature stages of Ixodes ricinus and Ixodes arboricola

This study assessed the parasitization of cavity-nesting birds and ground-nesting/foraging birds with larvae and nymphs of two Ixodes species, Ixodes ricinus and Ixodes arboricola. Totals of 679 (52.3%) I. ricinus and 619 (47.7%) I. arboricola ticks were collected from 15 species of passerine birds which were caught during the nesting and non-nesting periods of 2003-2006, in the south-eastern part of the Czech Republic, the Drahanská Vrchovina Uplands. In the non-nesting period from October to March, 6.8% (101/1492) of birds were infested with ticks, mainly with I. arboricola larvae. In the non-nesting period, the average intensity of infestation by I. arboricola and I. ricinus was 8.5 and 1.5 individuals per infested bird, respectively. In the nesting period from April to June, 21.6% (50/232) of birds were infested by both tick species but mainly with I. ricinus nymphs. The average intensity of infestation by I. ricinus and I. arboricola was 13.3 and 10.8 individuals per infested bird, respectively. Altogether, 23.2% of the infested birds were parasitized by both immature life stages of one or both tick species. From an enzootic perspective, co-feeding and co-infestation of I. ricinus and I. arboricola subadults on passerine birds might happen and may be important for the dissemination of tick-borne agents.

Genetic diversity and molecular epidemiology of Anaplasma

Anaplasma are obligate intracellular bacteria of cells of haematopoietic origin and are aetiological agents of tick-borne diseases of both veterinary and medical interest common in both tropical and temperate regions. The recent disclosure of their zoonotic potential has greatly increased interest in the study of these bacteria, leading to the recent reorganisation of Rickettsia taxonomy and to the possible discovery of new species belonging to the genus Anaplasma. This review is particularly focused on the common and unique characteristics of Anaplasma marginale and Anaplasma phagocytophilum, with an emphasis on genetic diversity and evolution, and the main distinguishing features of the diseases caused by the different Anaplasma spp. are described as well.

Borrelia miyamotoi in vectors and hosts in The Netherlands

Ixodes ticks transmit Borrelia burgdorferi sensu lato (s.l.), the causative agent of Lyme borreliosis (LB). These tick species also transmit Borrelia miyamotoi, which was recently found to cause infections in humans. We were interested in the prevalence of B. miyamotoi infection in ticks and natural hosts in The Netherlands, and to what extent ticks are co-infected with B. burgdorferi. In addition, erythema migrans has been sporadically described in B. miyamotoi-infected patients, but these skin lesions might as well represent co-infections with B. burgdorferi s.l. We therefore investigated whether B. miyamotoi was present in LB-suspected skin lesions of patients referred to our tertiary Lyme disease clinic. 3360 questing Ixodes ricinus nymphs as well as spleen tissue of 74 rodents, 26 birds and 10 deer were tested by PCR for the presence of B. miyamotoi. Tick lysates were also tested for the presence of B. burgdorferi s.l. Next, we performed a PCR for B. miyamotoi in 31 biopsies from LB-suspected skin lesions in patients visiting our tertiary Lyme center. These biopsies had been initially tested for B. burgdorferi s.l. by PCR, and the skin lesions had been investigated by specialized dermatologists. Out of 3360 unfed (or questing) nymphs, 313 (9.3%) were infected with B. burgdorferi s.l., 70 (2.1%) were infected with B. miyamotoi, and 14 (0.4%) were co-infected with B. burgdorferi s.l. and B. miyamotoi. Co-infection of B. burgdorferi s.l. with B. miyamotoi occurred more often than expected from single infection prevalences (p=0.03). Both rodents (9%) and birds (8%) were found positive for B. miyamotoi by PCR, whereas the roe deer samples were negative. Out of 31 LB-suspected skin biopsies, 10 (32%) were positive for B. burgdorferi s.l. while none were positive for B. miyamotoi. The significant association of B. burgdorferi s.l. with B. miyamotoi in nymphs implies the existence of mutual reservoir hosts. Indeed, the presence of B. miyamotoi DNA indicates systemic infections in birds as well as rodents. However, their relative contributions to the enzootic cycle of B. miyamotoi requires further investigation. We could not retrospectively diagnose B. miyamotoi infection using biopsies of LB-suspected skin lesions, supporting the hypothesis that B. miyamotoi is not associated with LB-associated skin manifestations. However, this warrants further studies in larger sets of skin biopsies. A prospective study focused on acute febrile illness after a tick bite could provide insight into the incidence and clinical manifestations of B. miyamotoi infection in The Netherlands.

The risk of exposure to rickettsial infections and human granulocytic anaplasmosis associated with Ixodes ricinus tick bites in humans in Romania: A multiannual study

Anaplasma phagocytophilum and spotted fever group Rickettsia are obligate intracellular Gram-negative tick-borne bacteria, among which several may cause clinical infections in humans. Several Rickettsia spp. and A. phagocytophilum are transmitted in Europe by Ixodes ricinus, the most common tick species feeding on humans in this area. The aim of this study was to evaluate the annual prevalence of Rickettsia spp. and A. phagocytophilum in I. ricinus collected from humans during three consecutive years. The mean prevalences of the infection with the investigated pathogens in I. ricinus ticks collected from human patients were as follows: A. phagocytophilum (5.56%), R. helvetica (4.79%) and R. monacensis (1.53%). In the present study, no significant differences of pathogens prevalence between the three years study period were observed, except the prevalence of R. helvetica, which had a significant increase in 2015, suggesting an increasing risk for humans to be exposed to this zoonotic pathogen.

Multiple-locus variable-number tandem repeat analysis potentially reveals the existence of two groups of Anaplasma phagocytophilum circulating in cattle in France with different wild reservoirs

Background

Anaplasma phagocytophilum is the causative agent of tick-borne fever, a disease with high economic impact for domestic ruminants in Europe. Epidemiological cycles of this species are complex, and involve different ecotypes circulating in various host species. To date, these epidemiological cycles are poorly understood, especially in Europe, as European reservoir hosts (i.e. vertebrate hosts enabling long-term maintenance of the bacterium in the ecosystem), of the bacterium have not yet been clearly identified. In this study, our objective was to explore the presence, the prevalence, and the genetic diversity of A. phagocytophilum in wild animals, in order to better understand their implications as reservoir hosts of this pathogen.

Methods

The spleens of 101 wild animals were collected from central France and tested for the presence of A. phagocytophilum DNA by msp2 qPCR. Positive samples were then typed by multi-locus variable-number tandem repeat (VNTR) analysis (MLVA), and compared to 179 previously typed A. phagocytophilum samples.

Results

Anaplasma phagocytophilum DNA was detected in 82/101 (81.2%) animals including 48/49 red deer (98%), 20/21 roe deer (95.2%), 13/29 wild boars (44.8%), and 1/1 red fox. MLVA enabled the discrimination of two A. phagocytophilum groups: group A contained the majority of A. phagocytophilum from red deer and two thirds of those from cattle, while group B included a human strain and variants from diverse animal species, i.e. sheep, dogs, a horse, the majority of variants from roe deer, and the remaining variants from cattle and red deer.

Conclusions

Our results suggest that red deer and roe deer are promising A. phagocytophilum reservoir host candidates. Moreover, we also showed that A. phagocytophilum potentially circulates in at least two epidemiological cycles in French cattle. The first cycle may involve red deer as reservoir hosts and cattle as accidental hosts for Group A strains, whereas the second cycle could involve roe deer as reservoir hosts and at least domestic ruminants, dogs, horses, and humans as accidental hosts for Group B strains.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-016-1888-4) contains supplementary material, which is available to authorized users.

Anaplasma phagocytophilum in sheep and goats in central and southeastern China

BACKGROUND

Anaplasma phagocytophilum is wide spread throughout the world and impacts both human and animal health. Several distinct ecological clusters and ecotypes of the agent have been established on the basis of various genetic loci. However, information on the genetic variability of A. phagocytophilum isolates in China represents a gap in knowledge. The objective of this study was to determine the prevalence and genetic characterization of A. phagocytophilum in small ruminants in central and southeastern China.

METHODS

The presence of A. phagocytophilum was determined in 421 blood samples collected from small ruminants by PCR. Positive samples were genetically characterized based on 16S rRNA and groEL genes. Statistical analyses were conducted to identify ecotypes of A. phagocytophilum strains, to assess their host range and zoonotic potential.

RESULTS

Out of 421 sampled small ruminants, 106 (25.2%) were positive for A. phagocytophilum. The positive rate was higher in sheep (35.1%, 40/114) than in goats (26.4%, 66/307) (P < 0.05). Sequence analyses revealed that the isolates identified in this study were placed on two separate clades, indicating that two 16S rRNA variants of A. phagocytophilum were circulating in small ruminants in China. However, analysis using obtained groEL sequences in this study formed one cluster, which was separate from other known ecotypes reported in Europe. In addition, a novel Anaplasma sp. was identified and closely related to an isolate previously reported in Hyalomma asiaticum, which clustered independently from all recognized Anaplasma species.

CONCLUSIONS

A molecular survey of A. phagocytophilum was conducted in sheep and goats from ten provinces in central and southeastern China. Two 16S rRNA variants and a new ecotype of A. phagocytophilum were identified in small ruminants in China. Moreover, a potential novel Anaplasma species was reported in goats. Our findings provide additional information on the complexity of A. phagocytophilum in terms of genetic diversity in China.

Molecular Detection of Tick-Borne Pathogens in Humans with Tick Bites and Erythema Migrans, in the Netherlands

BACKGROUND

Tick-borne diseases are the most prevalent vector-borne diseases in Europe. Knowledge on the incidence and clinical presentation of other tick-borne diseases than Lyme borreliosis and tick-borne encephalitis is minimal, despite the high human exposure to these pathogens through tick bites. Using molecular detection techniques, the frequency of tick-borne infections after exposure through tick bites was estimated.

METHODS

Ticks, blood samples and questionnaires on health status were collected from patients that visited their general practitioner with a tick bite or erythema migrans in 2007 and 2008. The presence of several tick-borne pathogens in 314 ticks and 626 blood samples of this cohort were analyzed using PCR-based methods. Using multivariate logistic regression, associations were explored between pathogens detected in blood and self-reported symptoms at enrolment and during a three-month follow-up period.

RESULTS

Half of the ticks removed from humans tested positive for Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum, Candidatus Neoehrlichia mikurensis, Rickettsia helvetica, Rickettsia monacensis, Borrelia miyamotoi and several Babesia species. Among 92 Borrelia burgdorferi s. l. positive ticks, 33% carried another pathogen from a different genus. In blood of sixteen out of 626 persons with tick bites or erythema migrans, DNA was detected from Candidatus Neoehrlichia mikurensis (n = 7), Anaplasma phagocytophilum (n = 5), Babesia divergens (n = 3), Borrelia miyamotoi (n = 1) and Borrelia burgdorferi s. l. (n = 1). None of these sixteen individuals reported any overt symptoms that would indicate a corresponding illness during the three-month follow-up period. No associations were found between the presence of pathogen DNA in blood and; self-reported symptoms, with pathogen DNA in the corresponding ticks (n = 8), reported tick attachment duration, tick engorgement, or antibiotic treatment at enrolment.

CONCLUSIONS

Based on molecular detection techniques, the probability of infection with a tick-borne pathogen other than Lyme spirochetes after a tick bite is roughly 2.4%, in the Netherlands. Similarly, among patients with erythema migrans, the probability of a co-infection with another tick-borne pathogen is approximately 2.7%. How often these infections cause disease symptoms or to what extend co-infections affect the course of Lyme borreliosis needs further investigations.

Nested coevolutionary networks shape the ecological relationships of ticks, hosts, and the Lyme disease bacteria of the Borrelia burgdorferi (s.l.) complex

Background

The bacteria of the Borrelia burgdorferi (s.l.) (BBG) complex constitute a group of tick-transmitted pathogens that are linked to many vertebrate and tick species. The ecological relationships between the pathogens, the ticks and the vertebrate carriers have not been analysed. The aim of this study was to quantitatively analyse these interactions by creating a network based on a large dataset of associations. Specifically, we examined the relative positions of partners in the network, the phylogenetic diversity of the tick’s hosts and its impact on BBG circulation. The secondary aim was to evaluate the segregation of BBG strains in different vectors and reservoirs.

Results

BBG circulates through a nested recursive network of ticks and vertebrates that delineate closed clusters. Each cluster contains generalist ticks with high values of centrality as well as specialist ticks that originate nested sub-networks and that link secondary vertebrates to the cluster. These results highlighted the importance of host phylogenetic diversity for ticks in the circulation of BBG, as this diversity was correlated with high centrality values for the ticks. The ticks and BBG species in each cluster were not significantly associated with specific branches of the phylogeny of host genera (R² = 0.156, P = 0.784 for BBG; R² = 0.299, P = 0.699 for ticks). A few host genera had higher centrality values and thus higher importance for BBG circulation. However, the combined contribution of hosts with low centrality values could maintain active BBG foci. The results suggested that ticks do not share strains of BBG, which were highly segregated among sympatric species of ticks.

Conclusions

We conclude that BBG circulation is supported by a highly redundant network. This network includes ticks with high centrality values and high host phylogenetic diversity as well as ticks with low centrality values. This promotes ecological sub-networks and reflects the high resilience of BBG circulation. The functional redundancy in BBG circulation reduces disturbances due to the removal of vertebrates as it allows ticks to fill other biotic niches.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-016-1803-z) contains supplementary material, which is available to authorized users.

Parallelisms and Contrasts in the Diverse Ecologies of the Anaplasma phagocytophilum and Borrelia burgdorferi Complexes of Bacteria in the Far Western United States

Anaplasma phagocytophilum and Borrelia burgdorferi are two tick-borne bacteria that cause disease in people and animals. For each of these bacteria, there is a complex of closely related genospecies and/or strains that are genetically distinct and have been shown through both observational and experimental studies to have different host tropisms. In this review we compare the known ecologies of these two bacterial complexes in the far western USA and find remarkable similarities, which will help us understand evolutionary histories and coadaptation among vertebrate host, tick vector, and bacteria. For both complexes, sensu stricto genospecies (those that infect humans) share a similar geographic range, are vectored mainly by ticks in the Ixodes ricinus-complex, utilize mainly white-footed mice (Peromyscus leucopus) as a reservoir in the eastern USA and tree squirrels in the far west, and tend to be generalists, infecting a wider variety of vertebrate host species. Other sensu lato genospecies within each complex are generally more specialized, occurring often in local enzootic cycles within a narrow range of vertebrate hosts and specialized vector species. We suggest that these similar ecologies may have arisen through utilization of a generalist tick species as a vector, resulting in a potentially more virulent generalist pathogen that spills over into humans, vs. utilization of a specialized tick vector on a particular vertebrate host species, promoting microbe specialization. Such tight host-vector-pathogen coupling could also facilitate high enzootic prevalence and the evolution of host immune-tolerance and bacterial avirulence.

Anaplasma phagocytophilum and Babesia spp. in roe deer (Capreolus capreolus), fallow deer (Dama dama) and mouflon (Ovis musimon) in Germany

Infections with the tick-borne pathogens Anaplasma phagocytophilum and Babesia spp. can cause febrile disease in several mammalian species, including humans. Wild ruminants in Europe are suggested to serve as reservoir hosts for particular strains or species of these pathogens. The aims of this study were to investigate the occurrence of A. phagocytophilum and Babesia spp. in roe deer (Capreolus capreolus), fallow deer (Dama dama) and mouflon (Ovis musimon orientalis) in Germany, and the diversity and host association of genetic variants of A. phagocytophilum and Babesia species. From 2009 to 2010, 364 spleen samples from 153 roe deer, 43 fallow deer and 168 mouflon from 13 locations in Germany were tested for DNA of A. phagocytophilum and Babesia spp. by real-time PCR or conventional PCR, respectively. Variants of A. phagocytophilum were investigated with a nested PCR targeting the partial 16S rRNA gene, and species of piroplasms were identified by sequencing. DNA of A. phagocytophilum was detected in 303 (83.2%) samples: roe deer, 96.1% (147/153); fallow deer, 72.1% (31/43); and mouflon, 74.4% (125/168). Sequence analysis of 16S rRNA-PCR products revealed the presence of nine different genetic variants. DNA of Babesia spp. was found in 113 (31.0%) samples: roe deer, 62.8% (96/153); fallow deer, 16.3% (6/43); and mouflon, 6.5% (11/168). Babesia capreoli, Babesia sp. EU1 (referred to also as B. venatorum), B. odocoilei-like and a Theileria species were identified. Co-infections with A. phagocytophilum and Babesia spp. were detected in 30.0% of the animals which were tested positive for A. phagocytophilum and/or Babesia spp. Roe deer had a significantly higher percentage of co-infections (60.8%), followed by fallow deer (14.0%) and mouflon (6.5%). Thus, the results suggest that roe deer plays a key role in the endemic cycles of the pathogens investigated.

Molecular analysis of Anaplasma phagocytophilum and Babesia divergens in red deer (Cervus elaphus) in Western Austria

Wild ungulates may act as reservoirs of various vector borne pathogens that can infect humans and domestic animals. In the present study, blood samples from 196 red deer (Cervus elaphus) from Western Austria (Vorarlberg, Tyrol and Salzburg) were collected on filter paper and tested for Anaplasmataceae, Piroplasmida, Rickettsia and filarioid helminths using molecular tools. Babesia divergens was detected in ten (5.1%) and Anaplasma phagocytophilum in three (1.5%) of the 196 samples. Filarioid helminths, Rickettsia spp. and Theileria spp. were not detected. These findings indicate that red deer may serve as reservoirs of Babesia divergens and Anaplasma phagocytophilum in Western Austria. Further investigations are needed to assess the presence of these pathogens in ticks in this geographical region, and the significance of these pathogens in both animals and humans.

Diversity of rickettsial pathogens in Columbian black-tailed deer and their associated keds (Diptera: Hippoboscidae) and ticks (Acari: Ixodidae)

Cervids host multiple species of ixodid ticks, other ectoparasites, and a variety of rickettsiae. However, diagnostic test cross-reactivity has precluded understanding the specific role of deer in rickettsial ecology. In our survey of 128 Columbian black-tailed deer (Odocoileus hemionus columbianus (Richardson)) and their arthropod parasites from two northern Californian herds, combined with reports from the literature, we identified four distinct Anaplasma spp. and one Ehrlichia species. Two keds, Lipoptena depressa (Say) and Neolipoptena ferrisi Bequaert, and two ixodid ticks, Ixodes pacificus Cooley and Kohls and Dermacentor occidentalis Marx, were removed from deer. One D. occidentalis was PCR-positive for E. chaffeensis; because it was also PCR-positive for Anaplasma sp., this is an Anaplasma/Ehrlichia co-infection prevalence of 4.3%. 29% of L. depressa, 23% of D. occidentalis, and 14% of deer were PCR-positive for Anaplasma spp. DNA sequencing confirmed A. bovis and A. ovis infections in D. occidentalis, A. odocoilei in deer and keds, and Anaplasma phagocytophilum strain WI-1 in keds and deer. This is the first report of Anaplasma spp. in a North America deer ked, and begs the question whether L. depressa may be a competent vector of Anaplasma spp. or merely acquire such bacteria while feeding on rickettsemic deer.

Molecular identification of Anaplasma marginale in two autochthonous South American wild species revealed an identical new genotype and its phylogenetic relationship with those of bovines

Background

Anaplasma marginale is a well-known cattle pathogen of tropical and subtropical world regions. Even though, this obligate intracellular bacterium has been reported in other host species different than bovine, it has never been documented in Myrmecophaga tridactyla (giant anteater) or Hippocamelus antisense (taruca), which are two native endangered species.

Methods

Samples from two sick wild animals: a Myrmecophaga tridactyla (blood) and a Hippocamelus antisense (blood and serum) were studied for the presence of A. marginale DNA through msp5 gene fragment amplification. Further characterization was done through MSP1a tandem repeats analysis and MLST scheme and the genetic relationship among previously characterized A. marginale sequences were studied by applying, eBURST algorithm and AMOVA analysis.

Results

Anaplasma marginale DNA was identified in the Myrmecophaga tridactyla and Hippocamelus antisense samples. Through molecular markers, we identified an identical genotype in both animals that was not previously reported in bovine host. The analysis through eBURST and AMOVA revealed no differentiation between the taruca/anteater isolate and the bovine group.

Conclusions

In the present publication we report the identification of A. marginale DNA in a novel ruminant (Hippocamelus antisense) and non-ruminant (Myrmecophaga tridactyla) host species. Genotyping analysis of isolates demonstrated the close relatedness of the new isolate with the circulation population of A. marginale in livestock. Further analysis is needed to understand whether these two hosts contribute to the anaplasmosis epidemiology.

First molecular survey and identification of Anaplasma spp. in white yaks (Bos grunniens) in China

Anaplasmosis is caused by a group of obligate intracellular bacteria in the genus Anaplasma, which are transmitted by ticks and infect humans, domestic animals and wildlife. This study was conducted to determine the prevalence and molecular characterization of Anaplasma spp. in semi-wild white yaks sampled in Tianzhu Tibetan Autonomous County, northwest China. Out of 332 samples tested, 35 (10·9%) were positive for Anaplasma spp. The positive rates were 6·2% (20/322) and 5·3% (17/322) for Anaplasma bovis and Anaplasma phagocytophilum in white yaks, respectively. None of the sample was positive for Anaplasma marginale. Two (0·6%) samples were simultaneously positive to A. bovis and A. phagocytophilum. Sequence analysis of the 16S rRNA gene revealed two genotypes (ApG1 and ApG2) of A. phagocytophilum and two sequence types (ST1 and ST2) of A. bovis in white yaks. This study is the first to document the presence of Anaplasma in white yaks. Our findings extend the host range for Anaplasma species and provide more valuable information for the control and management of anaplasmosis in white yaks.

Detection of Anaplasma phagocytophilum genotypes that are potentially virulent for human in wild ruminants and Ixodes ricinus in Central Italy

Human granulocytic anaplasmosis (HGA) is an emerging tick-borne zoonosis worldwide. As is the case for many tick-borne diseases, the epidemiological cycle is associated to the environmental conditions, including the presence of wild vertebrate reservoir hosts, vectors, climate and vegetation. In this study a total number of 87 spleen samples of wild ruminants carcasses from Central Italy, and 77 Ixodes ricinus collected from the same dead animals were screened for Anaplasma phagocytophilum by using Real Time PCR. A. phagocytophilum DNA was detected in 75%, 66.7% and 54.2% of the spleen samples from red deer (Cervus elaphus), Apennine chamois (Rupicapra pyrenaica ornata) and roe deer (Capreolus capreolus) respectively, whereas it was detected in the 31.2% of I. ricinus. A total of 27 positive samples were characterized by sequencing a portion of the groEL gene. Two A. phagocytophilum lineages could clearly be delineated from the phylogenetic tree. Four sequences from red deer, 2 from I. ricinus and 1 from Apennine chamois clustered into lineage I together with those previously described as virulent genotypes related to HGA. The presence of A. phagocytophilum DNA in the Apennine chamois represents the first report for this Italian endemic subspecies.

Evaluation of different nested PCRs for detection of Anaplasma phagocytophilum in ruminants and ticks

BACKGROUND

Anaplasma phagocytophilum is a causative agent of granulocytic anaplasmosis in mammals, which has a broad geographical distribution and a high degree of clinical diversity. Currently, numerous PCR assays have been developed and used for the detection of A. phagocytophilum in various specimens. However, their performance varies. The aim of this study was to evaluate the performance of five nested PCR assays by detection of 363 ruminant and tick samples, and to select the most appropriate methods for the sensitive detection of A. phagocytophilum in environmental or clinical samples.

RESULTS

Positive PCR results for A. phagocytophilum were obtained in 75 (20.7%), 42 (11.6%) and 19 (5.2%) specimens with primer sets EC (EC9/EC12a and SSAP2f/SSAP2r), EE (EE1/EE2 and EE3/EE4) and ge (ge3a/ge10r, ge9f/ge2), respectively. The amplification of template DNA with the primer set MSP (MAP4AP5/MSP4AP3, msp4f/msp4r) could not be obtained in both ruminants and ticks, and a low specificity of the EL primers [EL(569)F/EL(1193)R, EL(569)F/EL(1142)R] in tick samples was observed. Our results revealed that the nested PCR with primer set EC complementary to the 16S rRNA gene was the most sensitive assay for detection of A. phagocytophilum in ruminant and tick specimens. A. phagocytophilum was detected in 47 (35.1%) sheep, 12 (10.4%) cattle, and 17 (14.9%) ticks. Two A. phagocytophilum genotypes were identified, that varied between sheep and cattle in sample collection sites.

CONCLUSIONS

This report provides more valuable information for the diagnosis and management of granulocytic anaplasmosis in China.

Larvae of Ixodes ricinus transmit Borrelia afzelii and B. miyamotoi to vertebrate hosts

Background

Lyme borreliosis is the most common tick-borne human disease and is caused by Borrelia burgdorferi sensu lato (s.l.). Borrelia miyamotoi, a relapsing fever spirochaete, is transmitted transovarially, whereas this has not been shown for B. burgdorferi (s.l). Therefore, B. burgdorferi (s.l) is considered to cycle from nymphs to larvae through vertebrates. Larvae of Ixodes ricinus are occasionally B. burgdorferi (s.l) infected, but their vector competence has never been studied.

Methods

We challenged 20 laboratory mice with field-collected larvae of I. ricinus. A subset of these larvae was analysed for infections with B. burgdorferi (s.l) and B. miyamotoi. After three to four challenges, mice were sacrificed and skin and spleen samples were analysed for infection by PCR and culture.

Results

Field-collected larvae were naturally infected with B. burgdorferi (s.l) (0.62 %) and B. miyamotoi (2.0 %). Two mice acquired a B. afzelii infection and four mice acquired a B. miyamotoi infection during the larval challenges.

Conclusion

We showed that larvae of I. ricinus transmit B. afzelii and B. miyamotoi to rodents and calculated that rodents have a considerable chance of acquiring infections from larvae compared to nymphs. As a result, B. afzelii can cycle between larvae through rodents. Our findings further imply that larval bites on humans, which easily go unnoticed, can cause Lyme borreliosis and Borrelia miyamotoi disease.

The generalist tick Ixodes ricinus and the specialist tick Ixodes trianguliceps on shrews and rodents in a northern forest ecosystem--a role of body size even among small hosts

Background

Understanding aggregation of ticks on hosts and attachment of life stages to different host species, are central components for understanding tick-borne disease epidemiology. The generalist tick, Ixodes ricinus, is a well-known vector of Lyme borrelioses, while the specialist tick, Ixodes trianguliceps, feeding only on small mammals, may play a role in maintaining infection levels in hosts. In a northern forest in Norway, we aimed to quantify the role of different small mammal species in feeding ticks, to determine the extent to which body mass, even among small mammals, plays a role for tick load, and to determine the seasonal pattern of the two tick species.

Methods

Small mammals were captured along transects in two nearby areas along the west coast of Norway. All life stages of ticks were counted. Tick load, including both prevalence and intensity, was analysed with negative binomial models.

Results

A total of 359 rodents and shrews were captured with a total of 1106 I. ricinus (60.0 %) and 737 I. trianguliceps (40.4 %), consisting of 98.2 % larvae and 1.8 % nymphs of I. ricinus and 91.2 % larvae, 8.7 % nymphs and 0.1 % adult females of I. trianguliceps. Due to high abundance, Sorex araneus fed most of the larvae of both tick species (I. ricinus 61.9 %, I. trianguliceps 64.9 %) with Apodemus sylvaticus (I. ricinus 20.4 %, I. trianguliceps 10.0 %) and Myodes glareolus (I. ricinus 10.9 %, I. trianguliceps 9.5 %) as the next most important hosts. Individual A. sylvaticus and M. glareolus had higher infestation intensity than S. araneus, while Sorex minutus had markedly lower infestation intensity. The load of I. ricinus larvae and nymphs was related to body mass mainly up to ~10 g, while the load of I. trianguliceps was less dependent of body mass. The load of I. trianguliceps was higher in spring than in fall, while the seasonal pattern was reversed for I. ricinus with higher loads in fall.

Conclusions

Body mass was important for explaining load of I. ricinus mainly up to a body mass of ~10 g across a range of smaller mammalian hosts. Consistent with earlier work elsewhere in Europe, we found the highest tick infestation intensity on the wood mouse A. sylvaticus. However, this rodent species fed only 20.4 % of all I. ricinus larvae, while the much more abundant S. araneus fed 61.9 %. Our study emphasizes an important quantitative role of the common shrew S. araneus as a main host to I. ricinus larvae and to both I. trianguliceps larvae and nymphs. The partly seasonal distinct attachment pattern of I. ricinus and I. trianguliceps is evidence for niche separation.

Anaplasmataceae in wild ungulates and carnivores in northern Spain

Wild vertebrates are essential hosts for tick-borne diseases but data on the prevalence and diversity of Anaplasma spp. in wildlife are scarce. In this study, we used real-time PCR to investigate the distribution of Anaplasma species in spleen samples collected from 625 wild animals (137 cervids, 227 wild boar, and 261 carnivores) in two regions in northern Spain. A first generic real-time PCR assay was used to screen for the presence of Anaplasma spp. followed by a second species-specific multiplex real-time PCR or partial sequencing of the 16S rRNA gene for species identification. Anaplasma phagocytophilum was highly prevalent in cervids (64.2%), but it was absent from wild boar and carnivores. Interestingly, Anaplasma marginale and Anaplasma ovis were not detected in cervids, but Anaplasma centrale was identified in 1 roe deer and 1 red deer, A. bovis in 4 roe deer, and a novel Ehrlichia sp. in one badger. These findings were highly associated with the tick burden identified in the different hosts. Thus, Ixodes ricinus, the recognized vector of A. phagocytophilum in Europe, was the main tick species parasitizing cervids (93.5%, 1674/1791), whereas Dermacentor reticulatus was the most abundant in wild boar (76.1%, 35/46) and Ixodes hexagonus in carnivores (58.4%, 265/454). More investigations are needed to assess the impact of the different Anaplasma species in wildlife and the risk of transmission to domestic animals.

Anaplasma marginale and Anaplasma phagocytophilum: Rickettsiales pathogens of veterinary and public health significance

Anaplasma marginale and Anaplasma phagocytophilum are the most important tick-borne bacteria of veterinary and public health significance in the family Anaplasmataceae. The objective of current review is to provide knowledge on ecology and epidemiology of A. phagocytophilum and compare major similarities and differences of A. marginale and A. phagocytophilum. Bovine anaplasmosis is globally distributed tick-borne disease of livestock with great economic importance in cattle industry. A. phagocytophilum, a cosmopolitan zoonotic tick transmitted pathogen of wide mammalian hosts. The infection in domestic animals is generally referred as tick-borne fever. Concurrent infections exist in ticks, domestic and wild animals in same geographic area. All age groups are susceptible, but the prevalence increases with age. Movement of susceptible domestic animals from tick free non-endemic regions to disease endemic regions is the major risk factor of bovine anaplasmosis and tick-borne fever. Recreational activities or any other high-risk tick exposure habits as well as blood transfusion are important risk factors of human granulocytic anaplasmosis. After infection, individuals remain life-long carriers. Clinical anaplasmosis is usually diagnosed upon examination of stained blood smears. Generally, detection of serum antibodies followed by molecular diagnosis is usually recommended. There are problems of sensitivity and cross-reactivity with both the Anaplasma species during serological tests. Tetracyclines are the drugs of choice for treatment and elimination of anaplasmosis in animals and humans. Universal vaccine is not available for either A. marginale or A. phagocytophilum, effective against geographically diverse strains. Major control measures for bovine anaplasmosis and tick-borne fever include rearing of tick-resistant breeds, endemic stability, breeding Anaplasma-free herds, identification of regional vectors, domestic/wild reservoirs and control, habitat modification, biological control, chemotherapy, and vaccinations (anaplasmosis and/or tick vaccination). Minimizing the tick exposure activities, identification and control of reservoirs are important control measures for human granulocytic anaplasmosis.

Opening the black box of Anaplasma phagocytophilum diversity: current situation and future perspectives

Anaplasma phagocytophilum is a zoonotic obligate intracellular bacterium known to be transmitted by ticks belonging to the Ixodes persulcatus complex. This bacterium can infect several mammalian species, and is known to cause diseases with variable symptoms in many domestic animals. Specifically, it is the causative agent of tick-borne fever (TBF), a disease of important economic impact in European domestic ruminants, and human granulocytic anaplasmosis (HGA), an emerging zoonotic disease in Asia, USA and Europe. A. phagocytophilum epidemiological cycles are complex and involve different ecotypes, vectors, and mammalian host species. Moreover, the epidemiology of A. phagocytophilum infection differs greatly between Europe and the USA. These different epidemiological contexts are associated with considerable variations in bacterial strains. Until recently, few A. phagocytophilum molecular typing tools were available, generating difficulties in completely elucidating the epidemiological cycles of this bacterium. Over the last few years, many A. phagocytophilum typing techniques have been developed, permitting in-depth epidemiological exploration. Here, we review the current knowledge and future perspectives regarding A. phagocytophilum epidemiology and phylogeny, and then focus on the molecular typing tools available for studying A. phagocytophilum genetic diversity.

Anaplasma phagocytophilum prevalence in ticks and rodents in an urban and natural habitat in South-Western Slovakia

Background

Ixodes ricinus is the principal vector of Anaplasma phagocytophilum, the ethiological agent of granulocytic anaplasmosis in Europe. Anaplasmosis is an emerging zoonotic disease with a natural enzootic cycle. The reservoir competence of rodents is unclear. Monitoring of A. phagocytophilum prevalence in I. ricinus and rodents in various habitat types of Slovakia may contribute to the knowledge about the epidemiology of anaplasmosis in Central Europe.

Methods

Over 4400 questing ixodid ticks, 1000 rodent-attached ticks and tissue samples of 606 rodents were screened for A. phagocytophilum DNA by real-time PCR targeting the msp2 gene. Ticks and rodents were captured along six transects in an urban/suburban and natural habitat in south-western Slovakia during 2011–2014. Estimates of wildlife (roe deer, red deer, fallow deer, mouflon, wild boar) densities in the study area were taken from hunter’s yearly reports. Spatial and temporal differences in A. phagocytophilum prevalence in questing I. ricinus and relationships with relative abundance of ticks and wildlife were analysed.

Results

Overall prevalence of A. phagocytophilum in questing I. ricinus was significantly higher in the urban/suburban habitat (7.2 %; 95 % CI: 6.1–8.3 %) compared to the natural habitat (3.1 %; 95 % CI: 2.5–3.9 %) (χ² = 37.451; P < 0.001). Significant local differences in prevalence of infected questing ticks were found among transects within each habitat as well as among years and between seasons. The trapped rodents belonged to six species. Apodemus flavicollis and Myodes glareolus prevailed in both habitats, Microtus arvalis was present only in the natural habitat. I. ricinus comprised 96.3 % of the rodent-attached ticks, the rest were Haemaphysalis concinna, Ixodes trianguliceps and Dermacentor reticulatus. Only 0.5 % of rodent skin and 0.6 % of rodent-attached ticks (only I. ricinus) were infected with A. phagocytophilum. Prevalence of A. phagocytophilum in questing I. ricinus did not correlate significantly with relative abundance of ticks or with abundance of wildlife in the area.

Conclusion

The study confirms that urban I. ricinus populations are infected with A. phagocytophilum at a higher rate than in a natural habitat of south-western Slovakia and suggests that rodents are not the main reservoirs of the bacterium in the investigated area.

The role of wild canids and felids in spreading parasites to dogs and cats in Europe. Part II: Helminths and arthropods

Over the last few decades, ecological factors, combined with everchanging landscapes mainly linked to human activities (e.g. encroachment and tourism) have contributed to modifications in the transmission of parasitic diseases from domestic to wildlife carnivores and vice versa. In the first of this two-part review article, we have provided an account of diseases caused by protozoan parasites characterised by a two-way transmission route between domestic and wild carnivore species. In this second and final part, we focus our attention on parasitic diseases caused by helminth and arthropod parasites shared between domestic and wild canids and felids in Europe. While a complete understanding of the biology, ecology and epidemiology of these parasites is particularly challenging to achieve, especially given the complexity of the environments in which these diseases perpetuate, advancements in current knowledge of transmission routes is crucial to provide policy-makers with clear indications on strategies to reduce the impact of these diseases on changing ecosystems.

Presence of zoonotic agents in engorged ticks and hedgehog faeces from Erinaceus europaeus in (sub) urban areas

Background

European hedgehogs (Erinaceus europaeus) are hosts for Ixodes hexagonus and I. ricinus ticks, which are vectors for zoonotic microorganisms. In addition, hedgehogs may carry several enteric zoonoses as well. It is unclear to what extent a presence of pathogens in hedgehogs poses a risk to public health, as information on the presence of zoonotic agents in hedgehogs in urban areas is relatively scarce.

Methods

Engorged ticks and hedgehog faeces were collected from rehabilitating hedgehogs. Ticks were screened individually for presence of Borrelia burgdorferi sensu lato, B. miyamotoi, Anaplasma phagocytophilum, and Candidatus Neoehrlichia mikurensis using PCR-based assays. Faecal samples were screened for presence of Campylobacter, Salmonella, Giardia, Cryptosporidium, and extended-spectrum cephalosporin-resistant-Escherichia coli (ESC)-resistant E. coli, using both culture-based and PCR-based methods.

Results

Anaplasma phagocytophilum and Borrelia genospecies B. afzelii, B. spielmanii, B. garinii, and B. burgdorferi sensu stricto were detected in both I. hexagonus and I. ricinus ticks. Despite their widespread distribution in the Netherlands, B. miyamotoi and Candidatus N. mikurensis were not detected in collected ticks. Analysis of hedgehog faecal samples revealed the presence of Salmonella enterica subspecies enterica and Campylobacter jejuni. In addition, ESC-resistant E. coli were observed in high prevalence in faecal samples, but no Shiga-toxin producing-E.coli were detected. Finally, potentially zoonotic protozoan parasites were observed in hedgehog faecal samples as well, including Giardia duodenalis assemblage A, Cryptosporidium parvum subtypes IIaA17G1R1 and IIcA5G3, and C. hominis subtype IbA10G2.

Conclusions

European hedgehogs in (sub)urban areas harbor a number of zoonotic agents, and therefore may contribute to the spread and transmission of zoonotic diseases. The relatively high prevalence of B. burgdorferi s.l. and A. phagocytophilum in engorged ticks, suggests that hedgehogs contribute to their enzootic cycles in (sub)urban areas. To what extent can hedgehogs maintain the enteric zoonotic agents in natural cycles, and the role of (spill-back from) humans remains to be investigated.

Varying influences of selection and demography in host-adapted populations of the tick-transmitted bacterium, Anaplasma phagocytophilum

Background

The host range of a pathogenic bacterial strain likely influences its effective population size, which in turn affects the efficacy of selection. Transmission between competent hosts may occur more frequently for host generalists than for specialists. This could allow higher bacterial population densities to persist within an ecological community and increase the efficacy of selection in these populations. Conversely, specialist strains may be better adapted to their hosts and consequently achieve greater within-host population densities, with corresponding increases in selection efficacy. To assess these different hypotheses, we examined the effective population sizes of three strains of the bacterium Anaplasma phagocytophilum and categorized the varying roles of selection and demography on patterns of genetic diversity and divergence in these populations. A. phagocytophilum is a tick-transmitted, obligately intracellular pathogen. Strains of A. phagocytophilum display varying degrees of host specialization, making this a good species for exploring questions regarding host range, effective population size and selection efficacy.

Results

We found that a roe deer specialist harbored the most genetic diversity of the three A. phagocytophilum strains and correspondingly had the largest effective population size. Another strain that is ecologically specialized on rodents and insectivores had the smallest effective population size. However, these mammalian hosts are distantly related evolutionarily. The third strain, a host generalist, was intermediate in its effective population size between the other two strains. Evolutionary constraint on non-synonymous sites was pervasive in all three strains, although some slightly deleterious mutations may also be segregating in these populations. We additionally found evidence of genome-wide selective sweeps in the generalist strain, whereas signals of repeated bottlenecks were detected in the strain with the smallest effective population size.

Conclusions

A. phagocytophilum is a diverse bacterial species that differs among distinct strains in its effective population size, as well as how genetic diversity and divergence have been influenced by selection and demographic changes. In this species, host specialization may facilitate increased population growth and allow more opportunities for selection to act. These results provide insights into how host range has influenced evolutionary patterns of strain divergence in an emerging zoonotic bacterium.

Electronic supplementary material

The online version of this article (doi:10.1186/s12862-015-0335-z) contains supplementary material, which is available to authorized users.

Bacterial and protozoal agents of canine vector-borne diseases in the blood of domestic and stray dogs from southern Portugal

Background

The so-called canine vector-borne diseases (CVBD) are caused by a wide range of pathogens transmitted by arthropods. In addition to their veterinary importance, many of these canine vector-borne pathogens can also affect the human population due to their zoonotic potential, a situation that requires a One Health approach. As the prevalence of vector-borne pathogens in cats from southern Portugal has been recently evaluated, the aim of the present study was to assess if the same agents were present in dogs living in the same area, and to assess positivity-associated risk factors.

Methods

One thousand and ten dogs (521 domestic and 489 stray) from veterinary medical centres and animal shelters in southern Portugal were enrolled. Anaplasma spp./Ehrlichia spp., Bartonella spp., Borrelia burgdorferi sensu lato, Babesia spp., Hepatozoon spp. and Leishmania infantum infections were evaluated by polymerase chain reaction (PCR) assays in blood samples.

Results

Sixty-eight (6.7%) dogs were PCR-positive to at least one of the tested CVBD agent species, genera or complex, including one dog found positive to two different genera. Nineteen (1.9%) dogs were positive to Anaplasma spp./Ehrlichia spp., eight (0.8%) to B. burgdorferi s.l., 31 (3.1%) to Hepatozoon spp. and 11 (1.1%) to L. infantum. Anaplasma platys, Ehrlichia canis, B. burgdorferis.l. and Hepatozoon canis were identified by DNA sequencing, including one animal confirmed with both A. platys and H. canis. Furthermore, Wolbachia spp. was amplified in blood from four dogs. None of the tested dogs was positive by PCR for Bartonella spp. or Babesia spp.

Conclusions

The molecular identification of CVBD agents in southern Portugal, some of them with zoonotic concern, reinforces the importance to alert the veterinary community, owners and public health authorities to prevent the risk of transmission of vector-borne pathogens among dogs and to other vertebrate hosts including humans. The prevalence of the selected pathogens was lower than that previously found in cats from the same region, probably because veterinarians and owners are more aware of them in the canine population and control measures are used more often.

Vertical transmission of Bartonella schoenbuchensis in Lipoptena cervi

Background

Lipoptena cervi (Diptera: Hippoboscidae) is a hematophagous ectoparasite of cervids, which is considered to transmit pathogens between animals and occasionally to humans. The principal life stage that is able to parasitize new hosts is a winged ked that just emerged from a pupa. To facilitate efficient transmission of pathogens between hosts, vertical transmission from female deer keds to their offspring is necessary. We investigated vertical transmission of several vector-borne pathogens associated with cervids.

Methods

Deer keds from several locations in Hungary were collected between 2009 and 2012. All life stages were represented: winged free-ranging adults, wingless adults collected from Capreolus capreolus and Cervus elaphus, developing larvae dissected from gravid females, and fully developed pupae. The presence of zoonotic pathogens was determined using qPCR or conventional PCR assays performed on DNA lysates. From the PCR-positive lysates, a gene fragment was amplified and sequenced for confirmation of pathogen presence, and/or pathogen species identification.

Results

DNA of Bartonella schoenbuchensis was found in wingless males (2%) and females (2%) obtained from Cervus elaphus, dissected developing larvae (71%), and free-ranging winged males (2%) and females (11%). DNA of Anaplasma phagocytophilum and Rickettsia species was present in L. cervi adults, but not in immature stages. DNA of Candidatus Neoehrlichia mikurensis was absent in any of the life stages of L. cervi.

Conclusions

B. schoenbuchensis is transmitted from wingless adult females to developing larvae, making it very likely that L. cervi is a vector for B. schoenbuchensis. Lipoptena cervi is probably not a vector for A. phagocytophilum, Rickettsia species, and Candidatus N. mikurensis.

Molecular detection and characterization of Anaplasma spp. in sheep and cattle from Xinjiang, northwest China

BACKGROUND

Anaplasmosis is caused by obligate intracellular bacteria in the genus Anaplasma. These bacterial pathogens are transmitted by ticks and impact both human and animal health. This study was conducted to determine the prevalence and molecular characterization of Anaplasma spp. in ruminants sampled in Xinjiang, northwest China.

METHODS

A survey was performed in August 2012 in rural areas of six counties in Xinjiang province. A total of 250 blood samples from ruminants were collected and tested for the presence of Anaplasma spp. by PCR. Positive samples were genetically characterized based on the 16S rRNA and msp4 genes.

RESULTS

The results showed a high prevalence of Anaplasma spp. in ruminants, with at least three different Anaplasma species detected (A. phagocytophilum, A. bovis and A. ovis). The mean prevalence of single infection with each species was 17.6% (A. phagocytophilum), 4.8% (A. bovis) and 40.5% (A. ovis). Coinfection occurred in 20 (8.0%) animals. Phylogenetic analysis of the 16S rRNA gene of A. bovis and A. phagocytophilum revealed a higher degree of genetic diversity for the latter. The results for A. ovis showed genotypic variation among geographic regions in China. In addition, a closely related isolate to the canine pathogen A. platys was identified in ruminants.

CONCLUSIONS

This survey revealed a high prevalence of Anaplasma sp. infections in sheep and cattle in the northwestern border regions of China, indicating the potential risk of transboundary disease.

A molecular survey of vector-borne pathogens in red foxes (Vulpes vulpes) from Bosnia and Herzegovina

BACKGROUND

Red foxes (Vulpes vulpes) have recently been recognized as potential reservoirs of several vector-borne pathogens and a source of infection for domestic dogs and humans, mostly due to their close vicinity to urban areas and frequent exposure to different arthropod vectors. The aim of this study was to investigate the presence and distribution of Babesia spp., Hepatozoon canis, Anaplasma spp., Bartonella spp., 'Candidatus Neoehrlichia mikurensis', Ehrlichia canis, Rickettsia spp. and blood filaroid nematodes in free-ranging red foxes from Bosnia and Herzegovina.

METHODS

Spleen samples from a total of 119 red foxes, shot during the hunting season between October 2013 and April 2014 throughout Bosnia and Herzegovina, were examined for the presence of blood vector-borne pathogens by conventional PCRs and sequencing.

RESULTS

In the present study, three species of apicomplexan parasites were molecularly identified in 73 red foxes from the entire sample area, with an overall prevalence of 60.8%. The DNA of B. canis, B. cf. microti and H. canis was found in 1 (0.8%), 38 (31.9%) and 46 (38.6%) spleen samples, respectively. In 11 samples (9.2%) co-infections with B. cf. microti and H. canis were detected and one fox harboured all three parasites (0.8%). There were no statistically significant differences between geographical region, sex or age of the host in the infection prevalence of B. cf. microti, although females (52.9%; 18/34) were significantly more infected with H. canis than males (32.9%; 28/85). The presence of vector-borne bacteria and filaroid nematodes was not detected in our study.

CONCLUSION

This is the first report of B. canis, B. cf. microti and H. canis parasites in foxes from Bosnia and Herzegovina and the data presented here provide a first insight into the distribution of these pathogens among the red fox population. Moreover, the relatively high prevalence of B. cf. microti and H. canis reinforces the assumption that this wild canid species might be a possible reservoir and source of infection for domestic dogs.

Candidatus Neoehrlichia mikurensis and Anaplasma phagocytophilum: prevalences and investigations on a new transmission path in small mammals and ixodid ticks

Background

Small mammals are crucial for the life history of ixodid ticks, but their role and importance in the transmission cycle of tick-borne pathogens is mostly unknown. Candidatus Neoehrlichia mikurensis (CNM) and Anaplasma phagocytophilum are both tick-borne pathogens, and rodents are discussed to serve as main reservoir hosts for CNM but not for the latter especially in Germany. Analysing the prevalence of both pathogens in small mammals and their ticks in endemic regions may help to elucidate possible transmission paths in small mammal populations and between small mammals and ticks.

Methods

In 2012 and 2013, small mammals were trapped at three different sites in Germany. DNA was extracted from different small mammal tissues, from rodent neonates, foetuses and from questing and attached ticks. DNA samples were tested for CNM and A. phagocytophilum by real-time PCR. Samples positive for A. phagocytophilum were further characterized at the 16S rRNA gene locus.

Results

CNM was detected in 28.6% of small mammals and in 2.2% of questing and 3.8% of attached ticks. Altogether 33 positive ticks were attached to 17 different hosts, while positive ticks per host ranged between one and seven. The prevalences for this pathogen differed significantly within small mammal populations comparing sites (χ²: 13.3987; p: 0.0004) and between sexes. Male rodents had an approximately two times higher chance of infection than females (OR: 1.9652; 95% CI: 1.32-2.92). The prevalence for CNM was 31.8% (95% CI: 22-44) in rodent foetuses and neonates (23 of 67) from positive dams, and 60% (95% CI: 35.7-80.25) of positive gravid or recently parturient rodents (9 out of 15) had at least one positive foetus or neonate. Anaplasma phagocytophilum was detected at a low percentage in rodents (0-5.6%) and host-attached ticks (0.5-2.9%) with no significant differences between rodent species. However, attached nymphs were significantly more often infected than attached larvae (χ²: 25.091; p: <0.0001).

Conclusion

This study suggests that CNM is mainly a rodent-associated pathogen and provides evidence for a potential transplacental transmission in rodents. In contrast, most of the rodent species captured likely represent only accidental hosts for A. phagocytophilum at the investigated sites.

Ixodes ricinus and Its Transmitted Pathogens in Urban and Peri-Urban Areas in Europe: New Hazards and Relevance for Public Health

Tick-borne diseases represent major public and animal health issues worldwide. Ixodes ricinus, primarily associated with deciduous and mixed forests, is the principal vector of causative agents of viral, bacterial, and protozoan zoonotic diseases in Europe. Recently, abundant tick populations have been observed in European urban green areas, which are of public health relevance due to the exposure of humans and domesticated animals to potentially infected ticks. In urban habitats, small and medium-sized mammals, birds, companion animals (dogs and cats), and larger mammals (roe deer and wild boar) play a role in maintenance of tick populations and as reservoirs of tick-borne pathogens. Presence of ticks infected with tick-borne encephalitis virus and high prevalence of ticks infected with Borrelia burgdorferi s.l., causing Lyme borreliosis, have been reported from urbanized areas in Europe. Emerging pathogens, including bacteria of the order Rickettsiales (Anaplasma phagocytophilum, "Candidatus Neoehrlichia mikurensis," Rickettsia helvetica, and R. monacensis), Borrelia miyamotoi, and protozoans (Babesia divergens, B. venatorum, and B. microti) have also been detected in urban tick populations. Understanding the ecology of ticks and their associations with hosts in a European urbanized environment is crucial to quantify parameters necessary for risk pre-assessment and identification of public health strategies for control and prevention of tick-borne diseases.

Molecular detection of tick-borne pathogens in captive wild felids, Zimbabwe

Background

The populations of wild felids in Africa, of especially lions (Panthera leo) and cheetahs (Acinonyx jubatus), are declining and the species are classified as vulnerable to extinction by the International Union for Conservation of Nature. As infections with tick-borne pathogens (TBP) can become more of a problem in wild felids, there are relatively few studies on TBP in wild felids in Africa and on how these infections might influence population numbers.

Methods

To gain further knowledge on TBP in captive wild felids in Southern Africa, we collected whole blood from captive lions, Southern African wildcats, cheetahs and servals in Zimbabwe for PCRs against the 18S rRNA gene of the piroplasmids (Babesia, Theileria, Cytauxzoon) and Hepatozoon spp., and the 16S rRNA gene of Ehrlichia and Anaplasma spp.

Results

Overall, 78% of the lions (67/86) and all the Southern African wildcats (6/6), cheetahs (4/4) and servals (2/2) had evidence of infection with at least one organism. The organisms most commonly detected in the lions were B. leo (59%; 51/86), B. vogeli (12%; 10/86) and H. felis (11%; 9/86) while all the Southern African wildcats and servals were positive for B. vogeli and all the cheetahs were positive for B. leo. Mixed infections were found in 22% (15/67) of the PCR positive lions, most commonly B. leo and H. felis (27%; 4/15), and in 1 (50%) of the servals (B. vogeli and A. phagocytophilum). Two lions were infected with three TBP, mainly B. leo, H. canis and T. parva, and B. leo, A. phagocytophilum and T. sinensis. Mixed infections with B. vogeli and A. phagocytophilum were seen in a serval and a Southern African wildcat. Other TBP were detected at a low prevalence (≤2%) in lions, mainly H. canis, T. sinensis, T. parva, C. manul, E. canis, and E. canis-like and B. odocoilei-like organisms.

Conclusions

Infections with tick-borne agents are common in captive wild felids in Zimbabwe.

Candidatus Neoehrlichia mikurensis and Anaplasma phagocytophilum in natural rodent and tick communities in Southern Hungary

The aim of this study was to investigate the natural cycle of the new human pathogenic bacteria Candidatus Neoehrlichia mikurensis and Anaplasma phagocytophilum in Southern Hungary. We collected rodents with live-traps (2010-2013) and questing ticks with flagging in 2012. Small mammals were euthanized, tissue samples were collected and all the ectoparasites were removed and stored in 70% alcohol. We found relatively low overall prevalence of tick infestation (8%). Samples were analysed for A. phagocytophilum and Candidatus N. mikurensis with multiplex quantitative real-time PCR targeting a part of major surface protein 2 (msp2) and the heat shock protein groEL genes, respectively. The overall prevalence in tissue samples was 6.6% (skin) and 5.1% (spleen) for A. phagocytophilum and 1.7% (skin) and 3.4% (spleen) for Candidatus N. mikurensis. Candidatus N. mikurensis was only detected in Apodemus flavicollis and Apodemus agrarius, while A. phagocytophilum was found in A. flavicollis, A. agrarius, Myodes glareolus, Microtus arvalis and Mus musculus samples. Prevalence of A. phagocytophilum in skin samples of A. flavicollis was significantly higher than prevalence of N. mikurensis (p<0.05). Among questing Ixodes ricinus ticks we found three (8.8%) individuals (female, male, nymph) infected with Candidatus N. mikurensis. Five (3.1%) questing ticks had A. phagocytophilum infection (one I. ricinus male, two Dermacentor reticulatus females and two Haemaphysalis concinna females). We found one I. ricinus nymph removed from a male A. flavicollis with A. phagocytophilum infection. Our study provides new data on the occurrence of these pathogens in rodent tissue samples, questing ticks and engorged ticks in Southern Hungary.

Ixodes ricinus and Its Transmitted Pathogens in Urban and Peri-Urban Areas in Europe: New Hazards and Relevance for Public Health

Tick-borne diseases represent major public and animal health issues worldwide. Ixodes ricinus, primarily associated with deciduous and mixed forests, is the principal vector of causative agents of viral, bacterial, and protozoan zoonotic diseases in Europe. Recently, abundant tick populations have been observed in European urban green areas, which are of public health relevance due to the exposure of humans and domesticated animals to potentially infected ticks. In urban habitats, small and medium-sized mammals, birds, companion animals (dogs and cats), and larger mammals (roe deer and wild boar) play a role in maintenance of tick populations and as reservoirs of tick-borne pathogens. Presence of ticks infected with tick-borne encephalitis virus and high prevalence of ticks infected with Borrelia burgdorferi s.l., causing Lyme borreliosis, have been reported from urbanized areas in Europe. Emerging pathogens, including bacteria of the order Rickettsiales (Anaplasma phagocytophilum, "Candidatus Neoehrlichia mikurensis," Rickettsia helvetica, and R. monacensis), Borrelia miyamotoi, and protozoans (Babesia divergens, B. venatorum, and B. microti) have also been detected in urban tick populations. Understanding the ecology of ticks and their associations with hosts in a European urbanized environment is crucial to quantify parameters necessary for risk pre-assessment and identification of public health strategies for control and prevention of tick-borne diseases.