Figure 1. Geographic distribution of roe deer samples collected. The map shows the location of the 25 state forest districts in Denmark. Numbers in circles indicate number of samples collect- ed in each district. Three districts, Klosterheden, Hanherred, and Nordjylland, did not submit samples. Also shown is the approxi- mate density of Ixodes ricinus ticks in Denmark, redrawn from (11) as shaded areas. Flagging is the technique of collecting ticks by moving a piece of fabric mounted on a stick through the vegetation for a given period of time. hunting season and from 125 animals in the fall hunting season. The mean age of roe deer was 2.9 years (median 2.5, range 0.5–10 years, Table 1); 60% were bucks, 36% were does, 4% were not defined. This skewed distribution is due to the fact that hunters are only allowed to hunt bucks during the first hunting period in the summer. Only 7% of the roe deer were heavily infested with ticks (defined as >100 engorged ticks/deer); 63% of these ani- mals came from Zealand (p = 0.026). B. burgdorferi and Bartonella spp. Seroprevalence was assessed on 227 samples. Of these, 83 (36.6%) had positive results on Borrelia IFA, but of Tickborne Infections in Denmark these 23 (10%) were borderline positive. Significant regional difference was found in Borrelia seropositivity when the mainland of Jutland was compared to the islands (Funen, Zealand, Lolland Falster, Bornholm; Figure 1), 27.1% versus 46.7% (p = 0.003). Borrelia-positive roe deer were found in 19 of 22 forest districts evaluated. Three districts in the northern part of Jutland were negative (Fussingø, Thy, and Ulborg; Figure 1), but only 9 blood samples came from these 3 districts. No significant differ- ences in Borrelia antibody prevalence were found for sex, age, and season. B. henselae and B. quintana seroprevalence was assessed on 227 samples. All samples were seronegative (95% confidence interval [CI] 0%–1.6%) A. phagocytophilum Seroprevalence was assessed on 227 samples. Of these, 217 (95.6%) were positive and 19 were borderline positive (8%). No significant difference in seroprevalence was seen for age, sex, season, or region. Among 237 samples tested by PCR for A. phagocytophilum, 101 (42.6%) were posi- tive in both 16S rRNA and msp2 PCR analysis. Only sam- ples positive for both genes (16S rRNA and msp2) were considered A. phagocytophilum positive. Four animals were PCR positive but had negative Anaplasma serologic results. Marked seasonal difference was found with 70 (62.5%) positive roe deer during the summer hunting season and 31 (24.8%) positive animals during the fall hunting season (p<0.0001) (Figure 2). Fewer animals were PCR positive in Jutland (39.6%) than on the islands (47.6%), and when adjusted for seasonal difference in sample collection, the difference was significant (p<0.05). A. phagocytophilum PCR-positive samples came from all 22 state forest dis- tricts (Table 2). Twenty-one samples from Jutland, Funen, Zealand, Falster, and Bornholm that were PCR positive for A. phagocytophilum were sequenced (GenBank accession no. AY776165) and revealed 100% homologies with known A. phagocytophilum sequences. Sequence variation was only encountered in 1 sample from Oxbøl in Jutland (no. AY776166). No significant difference in sex or age for PCR-positive samples was found. Ten samples were found positive for Anaplasma genus on the primary PCR but Emerging Infectious Diseases • www.cdc.gov/eid • Vol. 11, No. 7, July 2005 1057