Amy J. Ullmann

Association of Borrelia garinii and B. valaisiana with Songbirds in Slovakia

ABSTRACT In Europe, 6 of the 11 genospecies of Borrelia burgdorferi sensu lato are prevalent in questing Ixodes ricinus ticks. In most parts of Central Europe, B. afzelii, B. garinii, and B. valaisiana are the most frequent species, whereas B. burgdorferi sensu stricto, B. bissettii, and B. lusitaniae are rare. Previously, it has been shown that B. afzelii is associated with European rodents. Therefore, the aim of this study was to identify reservoir hosts of B. garinii and B. valaisiana in Slovakia. Songbirds were captured in a woodland near Bratislava and investigated for engorged ticks. Questing I. ricinus ticks were collected in the same region. Both tick pools were analyzed for spirochete infections by PCR, followed by DNA-DNA hybridization and, for a subsample, by nucleotide sequencing. Three of the 17 captured songbird species were infested with spirochete-infected ticks. Spirochetes in ticks that had fed on birds were genotyped as B. garinii and B. valaisiana, whereas questing ticks were infected with B. afzelii, B. garinii, and B. valaisiana. Furthermore, identical ospA alleles of B. garinii were found in ticks that had fed on the birds and in questing ticks. The data show that songbirds are reservoir hosts of B. garinii and B. valaisiana but not of B. afzelii. This and previous studies confirm that B. burgdorferi sensu lato is host associated and that this bacterial species complex contains different ecotypes.

Genome size and organization in the blacklegged tick, Ixodes scapularis and the Southern cattle tick, Boophilus microplus

Genome sizes and the organization of repetitive DNA were determined in the hard ticks Ixodes scapularis and Boophilus microplus using reassociation kinetics. The I. scapularis genome contains ∼2.15 pg (2.1 × 103 Mbp) of DNA and consists of no foldback (FB), 27% highly repetitive (HR), 39% moderately repetitive (MR), and 34% unique DNA. The B. microplus genome contains 7.5 pg (7.1 × 103 Mbp) DNA, and consists of 0.82% FB, 31% HR, 38% MR, and 30% unique DNA. In both species, repetitive sequences occur in a mixture of long and short period interspersion but most (65–80%) of the DNA follows a pattern of short period interspersion. Genome size and organization in the three tick species so far examined are distinct from other arthropods in having a greater proportion of MR, a lower proportion of unique and HR DNA of very low sequence complexity.

Three Multiplex Assays for Detection of Borrelia burgdorferi sensu lato and Borrelia miyamotoi sensu lato in Field-Collected Ixodes Nymphs in North America

Abstract Two hundred fifty New Jersey field-collected Ixodes scapularis Say ticks and 17 Colorado Ixodes spinipalpis Hadwen & Nuttall ticks were tested using three separate multiplex real-time polymerase chain reaction (PCR) assays. One assay targets the rrs-rrlA IGS region of Borrelia spp. to detect Borrelia burgdorferi sensu lato (s.l.) and Borrelia miyamotoi s.l. The second assay targets the ospA region of B. burgdorferi s.l. to detect B. burgdorferi sensu stricto (s.s.), Borrelia bissettii, and Borrelia andersonii. The final assay targets the glpQ region of B. miyamotoi s.l. to differentiate B. miyamotoi LB-2001 and Borrelia lonestari. A testing scheme combining these tests yielded 18% of tested I. scapularis ticks surveyed from New Jersey positive for B. burgdorferi s.s., 3.2% I. scapularis ticks positive for B. miyamotoi LB-2001, and 41.2% I. spinipalpis ticks positive for B. bissettii surveyed from Colorado.

Bacteriolytic Activity of Selected Vertebrate Sera for Borrelia burgdorferi Sensu Stricto and Borrelia bissettii

An in vitro assay to evaluate the bacteriolytic activity of the complement pathway was applied to 2 strains of Borrelia bissettii, CO501 and DN127, and compared with that of B. burgdorferi sensu stricto B31. Sera from mule deer (Odocoileus hemionus) and the Western Fence lizard (Sceloporus occidentalis) were completely borreliacidal for B. burgdorferi and for both strains of B. bissettii. Serum from Bobwhite quail (Colinus virginianus) was nonlytic for B. burgdorferi and partially lytic for B. bissettii strains, CO-501 and DN127. Serum from a New Zealand White rabbit (Oryctolagus cuniculus) was partially lytic for all 3 strains of Borrelia, whereas serum from white-footed mice (Peromyscus leucopus) were nonlytic for all 3 Borrelia strains. The spectrum of complement sensitivity of B. bissettii appears to be similar to that of European B. afzelii in that tested rodent serum is not lytic to these 2 genospecies. Interestingly, both B. bissettii and B. afzelii have been found to be closely associated with rodents. Complement sensitivity demonstrated in these experiments may suggest and possibly predict specific reservoir–host associations.

Elimination of Borrelia burgdorferi and Anaplasma phagocytophilum in Rodent Reservoirs and Ixodes scapularis Ticks Using a Doxycycline Hyclate-Laden Bait

A field trial was conducted in a Lyme disease-endemic area of New Jersey to determine the efficacy of a doxycyline hyclate rodent bait to prophylactically protect and cure small-mammal reservoirs and reduce infection rates in questing Ixodes scapularis ticks for Borrelia burgdorferi and Anaplasma phagocytophilum. The doxycycline-laden bait was formulated at a concentration of 500 mg/kg and delivered during the immature tick feeding season in rodent-targeted bait boxes. The percentage of infected small mammals recovered from treated areas after 2 years of treatment was reduced by 86.9% for B. burgdorferi and 74% for A. phagocytophilum. Infection rates in questing nymphal ticks for both B. burgdorferi and A. phagocytophilum were reduced by 94.3% and 92%, respectively. Results from this study indicate that doxycycline-impregnated bait is an effective means of reducing infection rates for B. burgdorferi and A. phagocytophilum in both rodent reservoirs and questing I. scapularis ticks.

A Preliminary Linkage Map of the Hard Tick, Ixodes Scapularis

A linkage map of the Ixodes scapularis genome was constructed, based upon segregation amongst 127 loci. These included 84 random amplified polymorphic DNA (RAPD) markers, 32 Sequence‐Tagged RAPD (STAR) markers, 5 cDNAs, and 5 microsatellites in 232 F1 intercross progeny from a single, field‐collected P1 female. A preliminary linkage map of 616 cM was generated across 14 linkage groups with one marker every 10.8 cM. Assuming a genome size of ≈ 109 bp, the relationship of physical to genetic distance was found to be ≈ 300 kb/cM in the I. scapularis genome.

Novel Relapsing Fever Spirochete in Bat Tick

Novel Relapsing Fever Spirochete in Bat Tick

Molecular Characterization of a New Isolate of Borrelia lusitaniae Derived from Apodemus sylvaticus in Portugal

A total of 196 small mammals were collected in Portugal and tested for Borrelia burgdorferi sensu lato. Tissue samples were taken from each animal and cultured in Barbour-Stoenner-Kelly (BSK)-II medium. The single strain of spirochete isolated was confirmed as Borrelia lusitaniae by genetic analyses. This is the first report of B. lusitaniae isolated from Apodemus sylvaticus.

Immunization with adenoviral-vectored tick salivary gland proteins (SALPs) in a murine model of Lyme borreliosis.

Prior exposure of vertebrate hosts to tick salivary proteins can induce specific immunity to tick infestation, as well as affording protection against tick-transmitted Borrelia burgdorferi infection in the mammalian host. Vaccination using an adenovirus expression system to deliver 4 tick salivary proteins (Ad-Salps) derived from Ixodes scapularis, Salp15, Salp25A, Salp25D, and Isac, was explored. Results indicate that vaccination with tick salivary proteins in an adenoviral vector can be used to modulate a Th1 response in the host and partially control spirochete load in immunized mice after infected tick challenge.

A preliminary linkage map of the tick, Ixodes scapularis.

A linkage map of the Ixodes scapularis genome was constructed based upon segregation amongst 127 loci. These included 84 random amplified polymorphic DNA (RAPD) markers, 32 Sequence-Tagged RAPD (STAR) markers, 5 cDNAs, and 5 microsatellites in 232 F1 intercross progeny from a single, field-collected P1 female. A preliminary linkage map of 616 cM was generated across 14 linkage groups with one marker every 10.8 cM. Assuming a genome size of ∼109 bp, the relationship of physical to genetic distance is ∼300 kb/cM in the I. scapularis genome.