In the European Union, the recommended ante-mortem diagnostic methods for bovine tuberculosis (bTB) include the single intradermal cervical comparative tuberculin (SICCT) test and the interferon-gamma (IFN-γ) test as an ancillary test. The SICCT test has a moderate sensitivity (Se) and high specificity (Sp), while the IFN-γ test has good Se, but a lower Sp than the SICCT test. A retrospective Bayesian latent class analysis was conducted on 71,185 cattle from 806 herds chronically infected with bTB distributed across Northern Ireland (NI) to estimate the Se and Sp of the common ante-mortem tests and meat inspection. Analyses were also performed on data stratified by farming type and herd location to explore possible differences in test performance given the heterogeneity in the population. The mean estimates in chronically infected herds were: (1) 'standard' SICCT: Se 40.5-57.7%, Sp 96.3-99.7%; (2) 'severe' SICCT: Se 49.0%-60.6%, Sp 94.4-99.4%; (3) IFN-γ(bovine-avian) using a NI optical density (OD) cut-off difference of 0.05: IFN-γ(B-A): Se 85.8-93.0%, Sp 75.6-96.2%; (4) IFN-γ(bovine-avian) using a standard 'commercial' OD cut-off difference of 0.1: IFN-γ(B-A): Se 83.1-92.1%, Sp 83.1-97.3%; and (5) meat inspection: Se 49.0-57.1% Se, Sp 99.1-100%. Se estimates were lower in cattle from dairy farms than from beef farms. There were no notable differences in estimates by location of herds. Certain population characteristics, such as production type, might influence the ability of bTB tests to disclose truly infected cases.

The black-spined toad, Duttaphrynus melanostictus, is widespread in South and South-East (SE) Asia, although recent molecular analyses have revealed that it represents a species complex (here called the D. melanostictus complex). Invasive populations of this toad have been detected in Madagascar since, at least, 2014. We here trace the origin of this introduction based on mitochondrial DNA sequences of 340 samples. All 102 specimens from Madagascar have identical sequences pointing to a single introduction event. Their haplotype corresponds to a lineage occurring in Cambodia, China, Laos, Thailand, Vietnam, and some locations of eastern Myanmar and northern Malaysia, here named the SE Asian lineage. Within this lineage, specimens from one location in Cambodia and three locations in Vietnam have the same haplotype as found in Madagascar. This includes Ho Chi Minh City, which has a major seaport and might have been the source for the introduction. Species distribution models suggest that the current range of the Madagascan invasive population is within the bioclimatic space occupied by the SE Asian lineage in its native range. The potential invasion zone in Madagascar is narrower than suggested by models from localities representing the full range of the D. melanostictus complex. Thus, an accurate taxonomy is essential for such inferences, but it remains uncertain if the toad might be able to spread beyond the potential suitable range because (1) knowledge on species-delimitation of the complex is insufficient, and (2) the native range in SE Asia might be influenced by historical biogeography or competition.

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Background We used genetic Multi-Locus VNTR Analysis (MLVA) data gathered from surveillance efforts to better understand the ongoing bovine tuberculosis (bTB) epidemic in Northern Irish cattle herds. We modelled the factors associated with Mycobacterium bovis MLVA genotype richness at three analytical scales; breakdown level, herd level, and patch level, and compared the results between dairy and non-dairy production types. Results In 83% of breakdowns and in 63% of herds, a single MLVA genotype was isolated. Five or more MLVA genotypes were found in less than 3 % of herds. Herd size and the total number of reactors were important explanatory variables, suggesting that increasing MLVA genotype richness was positively related to increases in the number of host animals. Despite their smaller relative size, however, the highest MLVA genotype richness values were observed in non-dairy herds. Increasing inwards cattle movements were important positive predictors of MLVA genotype richness, but mainly in non-dairy settings. Conclusions The principal finding is that low MLVA genotype richness indicates that small-scale epidemics, e.g. wildlife, contiguous farms, and within-herd recrudescence, are important routes of M. bovis infection in cattle herds. We hypothesise that these mechanisms will maintain, but may not explicitly increase, MLVA genotype richness. The presence of elevated MLVA richness is relatively rare and likely indicates beef fattening enterprises, which purchase cattle from over long distances. Cattle movements were furthermore an important predictor of MLVA genotype richness in non-dairy herds, but not in dairy herds; this may represent reduced cattle purchasing levels in dairy enterprises, compared to beef. These observations allude to the relative contribution of different routes of bTB infection between production types; we posit that infection associated with local factors may be more evident in dairy herds than beef herds, however in beef herds, inwards movements offer additional opportunities for introducing M. bovis into the herd. Electronic supplementary material The online version of this article (10.1186/s12866-019-1530-7) contains supplementary material, which is available to authorized users.