Limits...
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

View Article: PubMed Central - PubMed

ABSTRACT

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.

No MeSH data available.


Minimum spanning tree of the 198 A. phagocytophilum database samples according to their host species. Each circle represents a unique MLVA profile. The number of circle partitions corresponds to the number of A. phagocytophilum samples with the same genotype. Circles connected by a shaded background and tick lines differ by a maximum of one of the five VNTR markers, and could be considered as a “clonal complex”. The length of each branch is proportional to the number of differences. Each animal host species is represented by a specific color in the circle
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC5120488&req=5

Fig1: Minimum spanning tree of the 198 A. phagocytophilum database samples according to their host species. Each circle represents a unique MLVA profile. The number of circle partitions corresponds to the number of A. phagocytophilum samples with the same genotype. Circles connected by a shaded background and tick lines differ by a maximum of one of the five VNTR markers, and could be considered as a “clonal complex”. The length of each branch is proportional to the number of differences. Each animal host species is represented by a specific color in the circle

Mentions: We obtained complete MLVA profiles for 19/82 positive samples (typability: 23.2%), including 14 from red deer, two from roe deer and three from wild boars (Additional file 2: Table S2). These 19 profiles have never before been published [6, 15]. The cut-off value of samples generating complete profiles varied from 21.6 to 37.4 (Additional file 2: Table S2). Profiles were compiled and added to a database which already contained 179 MLVA profiles from previous studies [6, 15]. The 198 resulting profiles (available in Additional file 3: Table S3) were then represented on an MST (Fig. 1).Fig. 1


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
Minimum spanning tree of the 198 A. phagocytophilum database samples according to their host species. Each circle represents a unique MLVA profile. The number of circle partitions corresponds to the number of A. phagocytophilum samples with the same genotype. Circles connected by a shaded background and tick lines differ by a maximum of one of the five VNTR markers, and could be considered as a “clonal complex”. The length of each branch is proportional to the number of differences. Each animal host species is represented by a specific color in the circle
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5120488&req=5

Fig1: Minimum spanning tree of the 198 A. phagocytophilum database samples according to their host species. Each circle represents a unique MLVA profile. The number of circle partitions corresponds to the number of A. phagocytophilum samples with the same genotype. Circles connected by a shaded background and tick lines differ by a maximum of one of the five VNTR markers, and could be considered as a “clonal complex”. The length of each branch is proportional to the number of differences. Each animal host species is represented by a specific color in the circle
Mentions: We obtained complete MLVA profiles for 19/82 positive samples (typability: 23.2%), including 14 from red deer, two from roe deer and three from wild boars (Additional file 2: Table S2). These 19 profiles have never before been published [6, 15]. The cut-off value of samples generating complete profiles varied from 21.6 to 37.4 (Additional file 2: Table S2). Profiles were compiled and added to a database which already contained 179 MLVA profiles from previous studies [6, 15]. The 198 resulting profiles (available in Additional file 3: Table S3) were then represented on an MST (Fig. 1).Fig. 1

View Article: PubMed Central - PubMed

ABSTRACT

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.

No MeSH data available.