The bird tick, Ixodes brunneus Koch (Acari: Ixodidae): a rare and unusual tick in Mississippi.

Introduction

The bird-feeding tick, Ixodes brunneus, Koch (Acari: Ixodidae) (Figure 1), is an interesting tick which occurs in primarily in North America. All active stages of I. brunneus have been collected on birds of many species, but commonly reported hosts include blackbirds, jays, robins, sparrows, thrashers, thrushes, towhees, waxwings, and wrens (Bishopp and Trembley 1945, Cooley and Kohls 1945). It does not bite humans. Although this species likely occurs throughout Mississippi, it has been collected only rarely (Goddard and Layton 2006). Numerous drag-cloth tick surveys by the author in Mississippi, conducted weekly for years, failed to find I. brunneus (Goddard 1992, 1997, Goddard et al. 2003, Goddard and Paddock 2005). This paper presents new records for the bird tick, description of a site where specimens may be readily collected, and comments on an apparent bacterial symbiont associated with the tick.

[FIGURE 1 OMITTED]

Tick collections and seasonality. All collections were made by dragging a 1-[m.sup.2] white flannel cloth through the woods, roadsides, and game/nature trails. Tick collections were made year-round and were performed as part of statewide tick/disease and ecology surveys; no systematic or targeted efforts were made to collect this particular species. A total of 52 Ixodes brunneus specimens have been collected to date in Mississippi (see records section for data) - 38 females and 14 males. Identification of 10 of the specimens was confirmed by personnel at the U.S. National Tick Collection, Georgia Southern University, Statesboro, GA and deposited there as voucher specimens. Mississippi records of I. brunneus consist of specimens collected from Choctaw, Marshall, Oktibbeha, and Scott counties from February -April, with the majority (41/52; 79%) collected in March. This is consistent with other studies in the U.S. which reported them collected in almost every month (Bishopp and Trembley 1945, Cooley and Kohls 1945), although predominantly between October and April. Interestingly, 48/52 (92%) total adult specimens ever collected in Mississippi were taken from one spot, a 30-m section of nature trail at Wall Doxey State Park, near Holly Springs, MS (see records section for lat/long data). This section of trail, approximately 2-m wide and mowed regularly, was surrounded by kudzu vines with a few large pine and hardwood trees nearby. It looked no different than other areas along the 4-km trail. Throughout the year, the spot was approximately 20% shaded.

Unidentified bacteria in I. brunneus. During a survey for tick-borne disease agents, 17 of the 52 ticks reported in this paper were analyzed for Rickettsia, Ehrlichia, and Borrelia species (Goddard et al. 2003). Abundant bacilliform bacteria were found in 12 of the 17 (71%) of I. brunneus tested. These organisms appeared to be concentrated in the salivary glands or midgut tissues, where massive infections were observed (Figure 2). Sometimes the organisms appeared "hooked" on the ends or linked together, resembling spirochetes. For this reason, PCR was used to rule out a Borrelia species, such as B. anserina. PCR amplification of DNA from a ...