Chastagner A. 1, Dugat T. 2 , Vourc’h G. 1, Verheyden H. 3, Legrand L. 4, Bachy V. 5, Chabanne L. 6, Joncour G. 7,
Maillard R. 8, Haddad N. 2, Boulouis H.-J.2, Bailly X. 1 & Leblond A. 9
1 : INRA, UR346 Epidémiologie Animale, F-63122 Saint Genès Champanelle, France ; 2: Université Paris-Est, Ecole Nat. Vét. d’Alfort, UMR BIPAR ENVA Anses UPEC USC
INRA, 94706 Maisons-Alfort, France ; 3 : INRA, CEFS, F-31326 CASTANET TOLOSAN, France ; 4 : Frank Duncombe Lab.; 14053 Caen Cedex 4, France; EA 4655 U2RM –
University of Caen Basse-Normandy, 14000 Caen, France ; 5 : Lab. Vet. Dept.du Rhône, Campus VetAgro Sup, 69280 Marcy l’Etoile , France ; 6 : Université de Lyon,
VetAgro Sup, F-69280 Marcy l’Etoile, France ; 7 : Groupe Vétérinaire de Callac, 22160 Callac , France ; 8: Ecole Nat. Vet.de Toulouse, Unité pathologie des ruminants UMR BIPAR 31076 Toulouse , France ; 9 : INRA UR346 Epidémiologie Animale,et Département Hippique, VetAgroSup, F-69280 Marcy L’Etoile, France
Context :
Anaplasma phagocytophilum is a tick-borne bacterium, responsible of the granulocytic anaplasmosis in mammals, which causes
important economic losses in cattle and sheep herds in Europe.
A better knowledge of the genetic diversity of A. phagocytophilum is necessary: to understand the bacterial transmission cycle and to
implement prevention and control plan.
Study objective::
To characterize the genetic diversity of A. phagocytophilum that circulate in ill cattle in France in order to identify host species that
participate in the same epidemiological cycle and might be potential reservoir hosts.
1. Samples
 104 cattle,
 11 horses,
 3 dogs
 40 roe deer
2. Extraction to DNA sequences
France (coll.: LABÉO – Frank Duncombe , LDA 22, LVD 69, VetAgro
Sup et SNGTV)
DNA extraction
in column from
blood or spleen
Detection by
qPCR
Amplification of
8 loci by nested
PCR
Preliminary
amplification by
WGA
Bretagne & Franche Comté (local hunt plan)
Vallons de Gascogne & Gardouch (coll. INRA Toulouse)
(b)
(a)
SANGER
sequencing
Results:
Three groups of A. phagocytophilum
genotypes were identified. No geographic
structure was observed in genotype
distribution.
•
cluster 1: cattle & roe deer
=> hypothesis: spill-over of strains
from roe deer to cattle because this
genotype was rare in cattle (<2%)
•
cluster 2: cattle only
•
cluster 3: cattle, horses, dogs and
American reference strains
Fig. (b): Geographic localization of genotypes
identified in the Supertree.
=> Reservoir hosts not identified for
clusters 2 & 3
Fig. (a): “SuperTree” built from DNA sequences of 8 loci of A. phagocytophilum
(msp4, groESL, typA, pleD, gyrA, recG, polA and one intergenic region) with Mr Bayes.
Discussion & perspectives:
The three groups of A. phagocytophilum co-existing in cattle from France could by linked with:
- a difference of cycle with different reservoir hosts (like rodents, hedgehogs, hares …)
- a difference of clinical symptoms or virulence
Further studies about the genetic diversity of A.phagocytophilum in a restricted area will be necessary to understand the contribution
of both domestic animals and potential reservoir hosts to the spread of the bacterium.
Financeurs :