Longitudinal studies of Sin Nombre virus in deer mouse-dominated ecosystems of Montana.

Sin Nombre virus (SNV), hosted by the deer mouse (Peromyscus maniculatus), is the primary etiologic agent of Hantavirus pulmonary syndrome (HPS) in North America. To improve our understanding of the epidemiology of HPS in the western United States, we conducted studies of population dynamics and SNV antibody prevalence in deer mouse populations for 6 years on 12 mark-recapture grids in Montana. Monthly numbers of deer mice ranged from zero to over 170 on 1-hectare grids. SNV antibody prevalence was higher than observed in studies in other parts of the United States, averaging 13% (0% to 50%), and peaking in May or June each year. Antibody-positive mice were older (heavier) (78% of positives were adults versus 52% of negatives) and more likely to be males (61% of positives versus 53.4% of negatives). A higher proportion of antibody-positive deer mice of all age-mass classes had scars than did antibody-negative mice. Month-to-month survivorship of antibody-positive adult mice was similar to that of antibody-negative mice, but survival of young antibody-positive deer mice was lower than antibody-negative deer mice. This is the first study to clearly suggest a detrimental effect of SNV infection on deer mice.

Performance characteristics of the Gen-Probe Probe Competition Assay used as a supplementary test for the Gen-Probe PACE 2 and 2C assays for detection of Chlamydia trachomatis.

The performance characteristics of the Gen-Probe Probe Competition Assay (PCA) used in conjunction with the Gen-Probe PACE 2 and 2C direct detection assays for Chlamydia trachomatis were examined. Data collected by five public health laboratories by using the Gen-Probe PACE 2 were pooled and analyzed. Of 25,081 endocervical and male urethral specimens tested by the PACE 2 assay, 773 were tested by PCA. Of 334 specimens initially positive by the PACE 2 assay with an initial PACE 2 result of greater than 2,000 relative light units (RLU), 333 (99.7%) were positive by PCA while 242 of 339 (71.4%) specimens with an initial result between the cutoff and 2,000 RLU were positive by PCA, and 35 of 100 (35%) specimens with initial results between 200 RLU and the cutoff were positive by PCA. An additional 10,938 specimens were tested by the PACE 2C assay. Of these, positive PCA results were obtained for 187 of 188 (99.5%) specimens with initial results of greater than 2,000 RLU, 99 of 163 (60.7%) of specimens in the range of cutoff to 2,000 RLU, and 12 of 100 (12%) in the range of 200 RLU to the cutoff. These results indicate that specimens greater than 2,000 RLU do not require a supplemental test and that additional positive results can be obtained by testing specimens with an initial result below the cutoff.

Hantavirus in Montana deer mouse populations: preliminary results.

Dynamics of small mammal populations and the prevalence of antibodies for hantavirus were determined in six locations in central and western Montana (USA). Eighteen live-trapping grids were trapped monthly from June through September 1994. Deer mouse (Peromyscus maniculatus) populations ranged from 0 to over 90 on one-hectare grids. Our bleeding technique had no apparent effect on survival of deer mice. Deer mice, meadow voles (Microtus pennsylvanicus), and sagebrush voles (Lagurus curtatus) were seropositive. Thirty-eight (8%) (range, 0% to 30%) of 471 deer mice were seropositive for hantavirus antibodies. Seropositive mice were older and had lower monthly survival rates than seronegative deer mice. We found no relationship between prevalence of hantavirus antibodies and population density.