The human pathogenic (Ap-ha) strain of Anaplasma phagocytophilum in Ixodes scapularis belongs to two genetically distinct clades. Anaplasma phagocytophilum in Ixodes scapularis

We report the detection of 13 genotypes of the ankyrin (ankA) gene among 76 infected blacklegged ticks. Haplotype network and phylogenetic analyses revealed that genotypes corresponding to the Ap-ha strain did not form a monophyletic assemblage. They formed two distinct clades, one of which was genetically more similar in nucleotide and amino acid sequences to genotypes in the clade containing the Ap-variant 1 strain.