Abstract
BACKGROUND: Diagnostic tests and knowledge of their diagnostic accuracies are important for animal trypanosomosis surveillance and treatment. METHODOLOGY: A cross-sectional study was conducted in November 2021 to compare the performance of rapid diagnostic test (RDT) and PCR-based assay for the detection of trypanosome infections. Random sampling and probability proportional to size sampling were used to sample study households and animals from the sampled household respectively. Animals were screened for the presence of trypanosomes using both tests. A total of 100 cattle (52 from Apac and 48 from Kiryandongo districts) were included in the study. The percentage of positive tests, sensitivity, and specificity of the tests using mini PCR as a reference were computed. Cohen's kappa statistics was computed to assess how well the rapid diagnostic test agrees with the mini PCR. McNemar's statistic assessed if the proportion of positive tests identified by mini PCR significantly differed from that identified by the rapid diagnostic test. RESULTS: The mini PCR test detected 31.2% Trypanosome spp positive samples in Kiryandongo while it detected only 5.7% positive samples in Apac district. The rapid diagnostic test (RDT) analysis detected 91.6% Trypanosome spp positive samples in Kiryandongo district and only 46.1% in Apac district. T. congolense was the most common Trypanosoma species identified in Apac (36.5%) and Kiryandongo (47.9%) by the RDT. The percentage of each of the Trypanosome species (T.vivax, T.congolense, and mixed infection of T.vivax and T. congolense) detected by RDT differed significantly (p < 0.001) between the two districts. The RDT had a high sensitivity of 94.4% (95% Confidence Interval (CI): 72.7-99.9) but a very low specificity of 36.6% (95% CI: 26.2-48.0). The kappa test showed evidence of only a slight agreement (kappa = 0.1547, Accuracy = 0.48 (95% Confidence Interval (CI): 0.379,0.5822) between the two tests. The observed agreement between the tests was 47% while the expected agreement was 37.84%. CONCLUSION: This study found high sensitivity but low specificity of RDT using mini PCR as a reference.