Casey-Bryars, MiriamTratalos, Jamie A.Graham, David A.Barrett, Damien...
11页
查看更多>>摘要：Background: A national programme to eradicate bovine viral diarrhoea (BVD) has been in place in Ireland since 2013. To inform decision making in the end stages of eradication, and support the development of post-eradication surveillance strategies, an understanding of risks of infection in a low prevalence system is required. Methods: A case-control study design was implemented. The study population comprised bovine herds that had calves born and tested negative for BVD virus (BVDV) every year from 2013 to 2019 (n = 46,219 herds). We defined cases as herds which had one or more test positive calves for the first time in 2019 (n = 204). Controls (n = 816) were randomly sampled from the herds which remained test negative in 2019. The effects of herd size, management system, inward movements, including those of potential trojan dams (pregnant animals brought into the herd that could potentially be carrying infected calves in utero), and proximity to herds testing positive in the preceding year, were investigated. Network analysis approaches were used to generate variables measuring connections with test positive herds through inward cattle movements. A generalised linear mixed model, including a county-level random effect, was used to explore these risk factors. Results: Our final model retained ln (herd size) (Odds Ratio (95% CI): 1.72 (1.40, 2.12)), distance from test positive herds (0.54 (0.44, 0.66) for each extra land-parcel boundary crossed to reach the closest herd which tested positive the preceding year), and ln (potential trojan dams + 1) (1.29 (1.05, 1.60)). The same variables were retained in the model where herds with confirmed transient infections only (n = 25) were excluded. Conclusions: Our findings suggest that care with biosecurity at farm boundaries and visitors and equipment entering the farm, and avoidance or careful risk assessment of purchasing potentially pregnant animals, may help prevent introduction of BVDV to low-risk herds. At policy level, consideration of herd size, proximity to test positive herds and purchasing patterns of potentially pregnant cattle may help target surveillance measures towards the end of the eradication programme.
Yang, D. AaronXiao, XunJiang, PingPfeiffer, Dirk U....
10页
查看更多>>摘要：Bayesian finite mixture models, frequently referred to as Bayesian latent class models have become increasingly common for diagnostic test data in the absence of a gold standard test. Most Bayesian analyses in the veterinary literature have dealt with a dichotomised diagnostic outcome. The use of Bayesian finite mixture models for continuous test outcomes, such as sample to positive (S/P) ratios produced by an ELISA, is much less common, despite continuous models taking advantage of all of the information captured in the test outcome. This paper revisits the idea of the Bayesian finite mixture model and provides a practical guide for researchers who would like to use this approach for modelling continuous diagnostic outcomes as it preserves all information from the observed data. Synthetic datasets and a dataset from literature were analysed to illustrate that a mixture model with continuous diagnostic outcomes can be used to estimate true prevalence and to evaluate test sensitivity and specificity. In addition, directly modelling the continuous test outcomes rather than dichotomising them, means that optimal cut-offs can be defined based on the test purpose rather than being determined before testing. Moreover, as animals with higher scores are more likely to be infected, using continuous data allows test interpretation to be made at the individual animal level. In contrast, dichotomization treats all animals above a cut-off as having the same infection risk. This study demonstrates that dichotomisation is not a 'must' when using Bayesian latent class analysis for diagnostic test data, and suggests that latent class analysis using continuous test outcomes should be favoured when evaluating veterinary diagnostic tests producing continuous outcomes.
查看更多>>摘要：Neospora caninum, an intracellular protozoan, has attracted much attention because of the etiology of reproductive disorders in cattle. Although numerous relevant studies have been published, the overall prevalence of Neospora caninum infection among cattle in mainland China is still unknown, and associated risk factors need to be evaluated to establish preventive measures. We systematically searched four databases for epidemiologic studies that investigated the prevalence and associated risk factors of this parasite among cattle in mainland China. A total of 33,945 cattle from 51 studies were tested. The pooled prevalence of Neospora caninum among cattle in mainland China was 13.69% (95% CI: 10.86%-17.12%) through the random-effects model, which showed high heterogeneity, I-2 = 98%. The analysis showed that Neospora infection-positive cows were 2.42 times more likely to abort than infection-negative cows (OR 2.42; 95% CI: 2.07-2.84). Our analysis indicated that Neospora-infection is widely distributed among cattle in China, which reinforces the importance of adequate prevention and control strategies to reduce economic losses for the cattle industry.
查看更多>>摘要：Dog-dog and dog-cat attacks can result in severe medical, financial, and emotional injury to pets and owners. The characteristics of dog-dog and dog-cat attack victims, the circumstances surrounding these attacks and the financial burden from veterinary visits is not reported in Australia. Medical records from 459 animals that were presented to the emergency service of four specialty hospitals in Melbourne, Australia in 2018 following a dog attack were assessed via univariate and multivariate methodologies with a retrospective case-control study design. Animals who had been attacked by a dog comprised 2.4% of the overall caseload at these four hospitals. Risk factors identified in dog-dog attack victims for presenting to a veterinary emergency hospital after being attacked were being cross-bred (OR = 1.4, p = 0.014, 95% CI = 1.07-1.84) and neutered (OR = 1.4, p = 0.035, 95% CI = 1.03-2.00). Being aged > 2-7years was protective (OR = 0.70, p = 0.010, CI = 0.48-0.88). Dogs from houses with a lower Socio-economic Indices for Areas score (SIEFA) were more likely to be attacked at home by a known attacker, compared to those from houses with a higher SIEFA score who were more likely to be attacked in public by a dog unknown to them (p = < 0.001). Cats who presented following a dog attack had a 46.3% survival to discharge, compared to 91.8% in dogs (p < 0.001). Final cost of treatment for dogs and cats was similar (median AU $380 vs AU $360, respectively). Further research is needed to evaluate the population of dogs and cats attacked by dogs, to inform and direct public education campaigns aimed at reducing their incidence and overall burdens.
查看更多>>摘要：The Southwest of France raises different species of poultry. These production activities present structural vulnerabilities to severe infectious diseases such as highly pathogenic avian influenza. Indeed, many farms have free-range flocks, multi-age and multi-species productions, while being located near wild bird migratory corridors. These factors may partly explain the H5 virus epidemics that occurred between 2015 and 2021. Their serious economic and technical consequences and psychological impact have generated solidarity, collective learning and operational cohesiveness among all poultry professionals. Consequently, a decision was made to conduct annual simulation exercises for a major health event in order to maintain a high level of vigilance and responsiveness within different poultry sectors. Three exercises took place, in 2017, 2018 and 2019, in semi-real conditions (real dates and compressed time) and according to different scenarios. They took place outside an epidemic context and have in common to focus on the initial phase of the crisis (suspicions, results of preliminary analyzes), which is critical to assess the reactivity of industry personnel in order to mitigate infectious disease spread. The preparation of the simulation exercises was based on a common methodology. They were created by an organizing team and each included up to 60 people (industry personnel, observers and auditors). These simulations highlighted several critical points: poultry professionals have detailed knowledge of the field, but this information can only be effectively obtained and used if there is already a poultry industry decision-making structure in place (with good networking); there is a need (1) for better information sharing within the industry; (2) to develop an assistance structure for producers directly involved in a crisis; and (3) to increase collaboration with State services in peacetime. Finally, several technical issues were raised regarding control zones; blocking poultry movements; production site quarantine; depopulation strategies; self-financing capacity of the poultry industry in the absence of governmental involvement; and enhanced mapping tools with real-time traceability of animal transportation.
查看更多>>摘要：We used cattle movement data in Ecuador for 2017 and 2018 to build two types of cattle networks: a network including all cattle movements accounting for a disease of rapid spread like foot and mouth disease and a network including only the cows accounting for brucellosis, a disease of slow evolution occurring mainly in adult females. Parishes (the smallest geographical units) were considered as nodes and cattle movements between parishes as links. Network indicators calculated at the annual and monthly levels were close for both types of networks. For both networks, the largest strong component at the annual level included > 90% of nodes and the largest weak component included all nodes indicating a very low fragmentation. A percolation analysis indicated that most of the parishes needed to be removed to eliminate the largest strong components. Based on some network characteristics we established that a highly transmissible disease could spread rapidly and that an infection of slower transmission such as brucellosis could spread within local clusters. These features should be taken into account when considering preventing measures in Ecuador in the case of an emerging disease like foot and mouth disease or control measures for an endemic disease like brucellosis.
Olsen, AbbeyNielsen, Henrik VedelAlban, LisHoue, Hans...
9页
查看更多>>摘要：Toxoplasma gondii infection in pigs is commonly diagnosed using serological tests that detect IgG antibodies targeted against the parasite. Such tests include enzyme-linked immunosorbent assay (ELISA), modified agglutination test (MAT), and western blot (WB), which are commercially available as rapid test kits. In this study, we evaluated the manufacturer recommended cut-off of ELISA-PrioCHECK test kit and determined a new optimal cut-off for identifying T. gondii infections in pigs. Assessment of the commercial ELISA kit was done by including data from two additional serological tests, MAT, and WB, applied to seven pig population categories with varying prevalences. A total of 233 plasma samples that were previously used in other studies for investigating T. gondii seroprevalence in pigs in Denmark were randomly selected for inclusion, including 95 samples that had previously been analysed with all three tests and an additional 138 samples that were analysed using the three serological tests for this study. In the absence of a gold standard test, a latent class model was fit to the data to obtain estimates of sensitivity and specificity for each of the tests along with prevalence in each of the populations. A cut-off that maximized the sensitivity and specificity of the ELISA test was then selected. The optimal cut-off value for percent of positive control (PP) in ELISA-PrioCHECK was estimated to be 27.7 PP, which is higher than the cut-off value of 20 PP that is recommended by the manufacturer. At this cut-off, the estimated sensitivities of ELISA, MAT and WB were 99.2% (96.3-100.0%), 96.3% (88.0-100.0%), and 89.8% (80.0-98.0%), respectively. The estimated specificities of ELISA, MAT and WB were 95.2% (92.5-97.6%), 99.6% (97.5-100.0%), and 98.2% (95.9-100.0%), respectively. Our findings have broad relevance to the use of the ELISA-PrioCHECK test kit for detecting Toxoplasma gondii infection in pigs.
查看更多>>摘要：The management of livestock diseases transmission is dependent on the effectiveness of livestock health institutions, livestock disease monitoring and reporting mechanisms, and the management of livestock markets. The relative weakness of such institutions and mechanisms in Low-Middle Income Countries increases the importance of livestock owners' livestock disease prevention choices. Understanding private demand for preventative disease measures is, therefore, all the more important. The accurate estimation of hypothetical demand for new livestock vaccines is important for policy makers, although challenging. The challenge relates to the nature of livestock disease and the hypothetical choice context. Individual decision making of livestock dependent households is an important mediating factor, within coupled human and natural systems, in the transmission of livestock diseases. Kenyan data (elsewhere presented) demonstrates that the stressors of a lack of rain and perceptions of financial well-being are associated with short-term changes in cognitive capacity. As a consequence, measuring and controling for various forms of choice heuristic use and changes in short-term cognitive capacity are important for robust demand analysis among marginalized populations. In estimating agro-pastoralists' demand for new contagious bovine pleuropneumonia (CBPP) vaccines in Kenya, this paper identifies the effects of respondent short-term cognitive capacity in completing discrete choice experimental task and the subsequent effects on willingness-to-pay (WTP) estimation. Results indicate a positive estimated relationship of fluid intelligence and choice heuristics on demand for new CBPP vaccines. The estimation of WTP for CBPP disease risk information is significantly lower using WTP space estimates rather than traditional preference space estimates.
NSTL
Elsevier