subtest, a test of general knowledge. The odds ratios defining the association between the presence of oropharyngeal ATCV-1 DNA and low performance on the cognitive tests were significantly correlated. As depicted in Fig. 2, the presence of ATCV-1 oropharyngeal DNA was associated with low performance on Trails A with an odds ratio of 5.2 (95% confidence interval, 1.63–16.7; P < 0.005) and low performance on the RBANS Total Score with an odds ratio of 4.3 (95% confidence interval, 1.4–12.8; P < 0.01). Within the RBANS there was a strong association between oropharyngeal ATCV-1 DNA and low performance on the attention domain (odds ratio, 8.0; 95% confidence interval, 1.7–37.6; P < 0.008). These associations were independent of the covariates of age, sex, race, socioeconomic status, educational level, place of birth, and current cigarette smoking. No significant differences occurred with a low level of performance on the other RBANS domains or on the test of information (all P > 0.1). Effect of ATCV-1 on Mouse Behavior and Cognition. A series of behavior tests were performed on an equal number of male and female mice gavaged with either C. heliozoae alone (control, n = 20) or C. heliozoae infected with ATCV-1 at a multiplicity of infection of 10 per cell for 5 h (C. heliozoae/ATCV-1 exposed, n = 30). The behavior tests were started 6 wk postinoculation. An open field test and dark–light box were used to evaluate the effects of viral exposure on general locomotor activity and anxiety (16, 17). No significant group differences occurred in either test. The effect of ATCV-1 exposure on learning and memory