Table 1.
Roadkill samples collected by USDA-WS and tested for rabies using the LN34 real-time RT-PCR test; mean percent positivity and 95% confidence interval is shown in the total line.
Fig 1.
Location of roadkill samples tested for rabies using the LN34 real-time RT-PCR test (red dots indicate positive results, black dots indicate negative or indeterminate results) relative to the 2018 oral rabies vaccination (ORV) zones (in blue) in the eastern U.S.
Table 2.
Details of roadkill samples that tested positive for rabies using the LN34 real-time RT-PCR assay. Presence of lyssavirus RNA is indicated by average LN34 Ct value (LN34) ≤ 35, where lower numbers generally indicate higher RNA levels. Actin Ct values (Actin) indicate presence of host β-actin mRNA and are indicative of sample quality, where high Ct values may indicate poor sample quality or RNA degradation. A full description of how questionnaires were filled out is described in the methods. Temperature (Temp).
Fig 2.
Photos of roadkills testing positive for rabies using the LN34 real-time RT-PCR test.
Sample order is the same as Table 2, from top left to bottom right.
Table 3.
Rabies case detection rates for roadkill samples tested by LN34 by sample collection location relative to ORV zone and sample quality. Location is qualitative relative to the location of the 2018 ORV zone. Case detection rate is the percent positive out of total tested. P-values represent results of Mid-P exact test for the following comparisons of case detection rate: (top) LN34 Poor Quality Samples vs LN34 Good Quality Samples and (bottom) LN34 All Tested vs USDA ERS DRIT case detection rate for the same location relative to the ORV zone.
Fig 3.
Brain condition (A), skull condition (B), and estimated number of days in the field (C) for 267 roadkill samples tested for rabies using the LN34 real-time RT-PCR test.
Percent of positive, negative and indeterminate samples are shown by the size of colored bars and correspond to the y-axis. Number of samples per condition/result is written on bars. Brain condition, skull condition, and days in field were all chosen from a list of limited responses (see Methods). Samples from AZ were excluded (n = 32).
Fig 4.
Current (A) and previous day (B) temperature in the field for 267 roadkill samples tested for rabies using the LN34 real-time RT-PCR test.
Temperature was recorded in °F. Boxplots show median plus 25% and 75% quartiles. Whiskers show largest observation less than or equal to 1.5 * interquartile range. Outliers are shown as dots. Samples with no temperature data (n = 12 for A, n = 13 for B) were excluded. Samples from AZ were excluded (n = 32).
Fig 5.
Cost-benefit analysis comparing proportion of percent of rabies infected animals predicted to be detected (left axis, black line) and cost per informative result (positive/negative result, right axis, orange graph) at different sample degradation score thresholds (x-axis).