The aim of this study was to describe the genetic diversity of Mycobacterium avium subsp. paratuberculosis (MAP) obtained from individual cows in Korea. Twelve MAP-positive fecal DNA samples and 19 MAP isolates were obtained from 10 cattle herds located in 5 provinces in Korea. In addition, 5 MAP isolates obtained from the Czech Republic and Slovakia and 3 isolates from Australia were genotyped for comparison with the domestic isolates. The most prevalent strains in Korea were of the “bison-type” genotype (23 of 31 fecal DNA/isolates) and were distributed nationwide. The remaining MAP isolates (8) and all of the foreign isolates were identified as “cattle-type”. The bison-type strains which were discriminated only as INMV 68 in variable-number tandem repeats of mycobacterial interspersed repetitive units (MIRU-VNTR) typing. Multilocus short sequence repeat (MLSSR) typing differentiated the bison-type strains into 3 different subtypes. The cattle-type strains were divided into 3 subtypes by MIRU-VNTR and 8 subtypes by MLSSR. The allelic diversities in the MIRU-VNTR and MLSSR results were calculated as 0.567 and 0.866, respectively. These results suggest that MIRU-VNTR typing cannot provide a sufficient description of the epidemiological situation of MAP. Therefore, an alternative method, such as MLSSR, is needed for typing of MAP strains to elucidate the molecular epidemiology of MAP infections. Overall, this study is the first epidemiological survey report in Korea using both MIRU-VNTR and MLSSR typing methods, and it has provided basic data necessary to elucidate the characteristics of MAP infections in Korea.
Animals ; Australia ; Cattle ; Czech Republic ; DNA ; Genetic Variation ; Genotype ; Korea ; Methods ; Molecular Epidemiology ; Mycobacterium avium subsp. paratuberculosis ; Mycobacterium avium ; Mycobacterium ; Paratuberculosis ; Slovakia ; Tandem Repeat Sequences

To draw inferences about the sensitivity and specificity of the newly developed ELISA test for bovine paratuberculosis (PTB) diagnosis and posterior distribution on the prevalence of PTB in a province of Korea, we applied Bayesian approach with Gibbs sampler to the data extracted from the prevalence study in 1999. The data were from a single test results without a designated gold test. The prevalence estimates for PTB in study population ranged 3.2~5.3% for conservative and 6.7~7.1% for liberal, depending on the priors used. The simulated specificities of the ELISA close to one another, ranging 84.7~90.6%, whereas the sensitivity was somewhat spread out depending largely on the priors with a range of 46.4~88.2%. Our findings indicate that the ELISA method appeared useful as a screening tool at a minimum level in comparison to other diagnostic tests available for this disease in terms of sensitivity. However, this advantage comes at a cost of having low specificity of the test.
Animals ; Bayes Theorem ; Cattle ; Cattle Diseases/*epidemiology ; Enzyme-Linked Immunosorbent Assay/*methods ; Korea/epidemiology ; Paratuberculosis/*epidemiology ; Prevalence

Paratuberculosis (PTB) is a major disease problem worldwide, and causes major economic losses in the dairy industry. Although PTB has been reported in Korea, no studies have been conducted to determine its prevalence and no program has been developed to control the disease. In this study, the sera of beef (n = 1,056) and dairy cattle (n = 1,105) from all provinces in Korea were tested to determine the prevalence of PTB using two different ELISA: an 'in house' modified absorbed ELISA (P-ELISA) based on sonicated antigen from Mycobacterium avium subsp. paratuberculosis ATCC 19698, and a commercial ELISA (C-ELISA). Receiver operating characteristic analysis was used to determine the cutoff point for P-ELISA. Based on C-ELISA results, the area under the curve for P-ELISA was 0.913 (95% CI, 0.883 to 0.943). Using a cutoff point of 0.100, P-ELISA showed a sensitivity of 62.0% and a specificity of 93.7%. The kappa value and the percent agreement between the two ELISAs were 0.322 and 92.5%, respectively. Both ELISAs showed a significant correlation between age and seropositivity (p < 0.01). According to C-ELISA, 71 of 2,161 sera (3.3%, 95 CI, 2.6% to 4.1%) were test-positive. The national true prevalence of PTB was estimated to be 7.1%. The findings suggest that a control program should be implemented to limit the spread of this disease, and that P-ELISA could be used as a screening test that produces results similar to C-ELISA.
Animals ; Antibodies, Bacterial/blood ; Cattle ; Cattle Diseases/*epidemiology/*microbiology ; Enzyme-Linked Immunosorbent Assay/veterinary ; Female ; Korea/epidemiology ; Male ; Mycobacterium avium subsp. paratuberculosis/*isolation & purification ; Paratuberculosis/blood/*epidemiology ; ROC Curve ; Sensitivity and Specificity ; Seroepidemiologic Studies