Anaplasma phagocytophilum strains from voles and shrews exhibit specific ankA gene sequences

Juliana Majazki,Richard Birtles,Kathrin Hartelt,Friederike D Von Loewenich,Nicole Wüppenhorst

doi:10.1186/1746-6148-9-235

Abstract

BackgroundAnaplasma phagocytophilum is a Gram-negative bacterium that replicates obligate intracellularly in neutrophils. It is transmitted by Ixodes spp. ticks and causes acute febrile disease in humans, dogs, horses, cats, and livestock. Because A. phagocytophilum is not transmitted transovarially in Ixodes spp., it is thought to depend on reservoir hosts to complete its life cycle. In Europe, A. phagocytophilum was detected in roe deer, red deer, wild boars, and small mammals. In contrast to roe deer, red deer and wild boars have been considered as reservoir hosts for granulocytic anaplasmosis in humans, dogs, and horses according to groESL- and ankA-based genotyping. A. phagocytophilum variants infecting small mammals in Europe have not been characterized extensively to date.ResultsWe amplified the total ankA open reading frames of 27 strains from voles and shrews. The analysis revealed that they harboured A. phagocytophilum strains that belonged to a distinct newly described ankA gene cluster. Further, we provide evidence that the heterogeneity of ankA gene sequences might have arisen via recombination.ConclusionsBased on ankA-based genotyping voles and shrews are unlikely reservoir hosts for granulocytic anaplasmosis in humans, dogs, horses, and livestock in Europe.

Highlights

Anaplasma phagocytophilum is a Gram-negative bacterium that replicates obligate intracellularly in neutrophils
The molecular characterization of A. phagocytophilum strains using groESL and ankA gene sequences revealed that red deer [11,30] and wild boar [31,32] might harbour variants that cause granulocytic anaplasmosis in humans, dogs, and horses
Small mammals were considered as reservoir hosts too, but it was shown that voles were infected with msp4 genotypes that differed from those of I. ricinus ticks [34]

Summary

Introduction

Anaplasma phagocytophilum is a Gram-negative bacterium that replicates obligate intracellularly in neutrophils It is transmitted by Ixodes spp. ticks and causes acute febrile disease in humans, dogs, horses, cats, and livestock. In contrast to roe deer, red deer and wild boars have been considered as reservoir hosts for granulocytic anaplasmosis in humans, dogs, and horses according to groESL- and ankA-based genotyping. Anaplasma phagocytophilum is a Gram-negative bacterium that replicates obligate intracellularly in neutrophils [1] It is tick-transmitted and causes acute febrile disease in humans [2], in companion animals such as dogs [3], horses [4], and cats [5] as well as in livestock such as sheep and cattle [6,7]. In Europe, A. phagocytophilum was detected amongst others in roe deer [22,23], red deer [23], wild boars [24], hedgehogs [25], and other small mammals [26]

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