Tick-borne infectious agents: Anaplasma capra, a bacterial species newly described in France

Anaplasma, agent responsible for anaplasmosis in many vertebrates

Anaplasma is an obligate intracellular bacterium found in blood cells and transmitted by ticks. Several species have been characterised for several decades as responsible for anaplasmosis in domestic animals (D) and/or humans (H): Anaplasma ovis (D), A. bovis (D), A. phagocytophilum (D/H), A. marginale (D), A. centrale (D) and A. platys (D). Depending on the species involved and the infected host, anaplasmosis results in fevers, anorexia, abortions, reduced production, which may lead to the death of the host. Reduced immunity associated with the presence of these bacteria predisposes infected animals to other parasitic or bacterial infections. These species are distributed worldwide, with ranges that may be related to those of the tick vector species.

A new bacterial species transmitted by ticks in small ruminants in Corsica. Photo credit : M.Gallois

Anaplasma capra in Europe, first identification in France

Anaplasma capra is a species recently characterised in China (2015) in goats and then sheep. Described in several Asian countries (Japan, Korea, Malaysia), it turns out to have a fairly wide host range, including various species of deer and humans. Scientists from the TIBODI team of UMR BIOEPAR (INRAE, ONIRIS) in collaboration with MNHN (Muséum National d'Histoire Naturelle) characterised this species for the first time in Europe in 2019 in deer in a zoological reserve located in the Brenne. Subsequently, thanks to collaboration with the GDS (Groupement de Défense Sanitaire), the GTV (Groupement Technique Vétérinaire) and Corsican analysis laboratories, these researchers also demonstrated its presence in sheep and goat breeding in Corsica, with sometimes significant rates of infected animals.

Molecular phylogeny based on the groEL gene showing the two distinct clades in Anaplasma capra in purple and the European lineage in green.
Strains of human origin are indicated by a red arrow and an icon. 

Molecular phylogeny: two distinct groups and a European lineage?

Nucleotide sequence comparisons carried out by the team and based on 3 genes allow us to distinguish two distinct groups or clades within the Anaplasma capra species. French isolates from cervids, sheep or goats are grouped in one of these two clades, within a lineage suggesting a recent and unique European origin. The clade grouping the European strains is different from that in which the Chinese strains characterised in humans are found. It therefore remains to be determined whether the European strains could be infectious to humans.

What are the tick vectors in Europe?

Several species of vector ticks could be responsible for the transmission of Anaplasma capra in Asia. However, these species are not present in France, either in continental France (Brenne) or in Corsica, two locations with very different climates, with distinct local fauna and tick species. Anaplasma capra therefore appears to have low vector specificity, and several tick species are suspected of being vectors of this bacterium in Europe.

SCIENTIFIC PARTNERS: GDS Corse (Groupement de Défense Sanitaire du Bétail), GTV Corse (Groupement Technique Vétérinaire), Laboratoires Cismonte and Pumonte of the Collectivité de Corse, Idèle (Groupe de Travail OSCAR "avortement des petits ruminants"), MNHN (Réserve zoologique de la Haute-Touche).

ASSOCIATED PUBLICATIONS :

Jouglin, M., C. Rispe, S. Grech-Angelini, M. Gallois and L. Malandrin (2022). "Anaplasma capra in sheep and goats on Corsica Island, France: A European lineage within A. capra clade II?" Ticks and Tick Borne Diseases 13(3):101934. https://doi.org/10.1016/j.ttbdis.2022.101934

Jouglin, M., B. Blanc, N. de la Cotte, S. Bastian, K. Ortiz and L. Malandrin (2019) "First detection and molecular identification of the zoonotic Anaplasma capra in deer in France". PLoS One 5;14(7):e0219184. https://doi.org/10.1371/journal.pone.0219184.