title: Distribution and molecular characterization of Wolbachia endosymbionts and filarial nematodes in Maryland populations of the lone star tick (Amblyomma americanum).
abstract: The lone star tick Amblyomma americanum is host to a wide diversity of endosymbiotic bacteria. We identified a novel Wolbachia symbiont infecting A. americanum. Multilocus sequence typing phylogenetically placed the endosymbiont in the increasingly diverse F supergroup. We assayed a total of 1031 ticks (119 females, 78 males and 834 nymphs in 89 pools) from 16 Maryland populations for infection. Infection frequencies in the natural populations were approximately 5% in females and <2% (minimum infection rate) in nymphs; infection was not detected in males. Infected populations were only observed in southern Maryland, suggesting the possibility that Wolbachia is currently invading Maryland A. americanum populations. Because F supergroup Wolbachia have been detected previously in filarial nematodes, tick samples were assayed for nematodes by PCR. Filarial nematodes were detected in 70% and 9% of Wolbachia-positive and Wolbachia-negative tick samples, respectively. While nematodes were more common in Wolbachia-positive tick samples, the lack of a strict infection concordance (Wolbachia-positive, nematode-negative and Wolbachia-negative, nematode-positive ticks) suggests that Wolbachia prevalence in ticks is not due to nematode infection. Supporting this hypothesis, phylogenetic analysis indicated that the nematodes were likely a novel species within the genus Acanthocheilonema, which has been previously shown to be Wolbachia-free.
authors.affiliation: The W. Harry Feinstone Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA.
authors.forename: Xing
authors.initials: X
authors.lastname: Zhang
authors.forename: Douglas E
authors.initials: DE
authors.lastname: Norris
authors.forename: Jason L
authors.initials: JL
authors.lastname: Rasgon
mesh_terms: D000818:Animals; D005260:Female; D005370:Filarioidea / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification; D026863:Ixodidae / Q000382:microbiology* / Q000469:parasitology*; D008297:Male; D008396:Maryland; D058885:Multilocus Sequence Typing; D009348:Nematoda / Q000382:microbiology; D009758:Nymph / Q000382:microbiology / Q000469:parasitology; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D013559:Symbiosis; D020577:Wolbachia / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification