gltA typing of Anaplasma strains related to A. platys: Taxonomical and one health implications

Species belonging to the genus Anaplasma (Rickettsiales) include bacteria of veterinary and public health importance. Beside the zoonotic Anaplasma phagocytophilum, A. platys, the etiological agent of canine cyclic thrombocytopenia, has been sporadically reported in clinically ill human patients. The ongoing emergence of novel strains related to this species in vertebrate hosts emphasises the need for genetic comparisons among strains identified in different regions of the world. In this paper we developed a PCR test suitable for amplification of the still undescribed gltA gene of Anaplasma strains related to A. platys from Mediterranean ruminants and applied on a panel of 248 samples. gltA sequencing allowed phylogenetic comparison with strains related to A. platys recently identified in China, and strains representative of the Anaplasmataceae family. Results suggest the designation of Candidatus A. turritanum, including Mediterranean A. platys - like strains, and Candidatus A. cinensis, including strains isolated in China. Data generated in this study are a solid reference for future epidemiological studies of novel unclassified strains related to A. platys and for their diagnosis and raise concern on their potential veterinary and public health implications encouraging investigating the suspected unexplored diversity within the genus Anaplasma in animals and human.

Automated summary

This study developed a PCR test for amplifying the gltA gene of Anaplasma strains related to A. platys from Mediterranean ruminants, allowing phylogenetic comparison with strains identified in China and representatives of the Anaplasmataceae family. The results suggest the designation of Candidatus A. turritanum for Mediterranean A. platys-like strains, and Candidatus A. cinensis for strains isolated in China, providing a solid reference for future epidemiological studies and emphasizing the need to investigate unexplored diversity within the genus Anaplasma.