A novel Bayesian Latent Class Model (BLCM) evaluates multiple continuous and binary tests: A case study for Brucella abortus in dairy cattle.

Bovine brucellosis, primarily caused by Brucella abortus, severely affects both animal health and human well-being. Accurate diagnosis is crucial for designing informed control and prevention measures. Lacking a gold standard test makes it challenging to determine optimal cut-off values and evaluate the diagnostic performance of tests. In this study, we developed a novel Bayesian Latent Class Model that integrates both binary and continuous testing outcomes, incorporating additional fixed (parity) and random (farm) effects, to calibrate optimal cut-off values by maximizing Youden Index. We tested 651 serum samples collected from six dairy farms in two regions of Henan Province, China with four serological tests: Rose Bengal Test, Serum Agglutination Test, Fluorescence Polarization Assay, and Competitive Enzyme-Linked Immunosorbent Assay. Our analysis revealed that the optimal cut-off values for FPA and C-ELISA were 94.2 mP and 0.403 PI, respectively. Sensitivity estimates for the four tests ranged from 69.7% to 89.9%, while specificity estimates varied between 97.1% and 99.6%. The true prevalences in the two study regions in Henan province were 4.7% and 30.3%. Parity-specific odds ratios for positive serological status ranged from 1.2 to 2.2 for different parity groups compared to primiparous cows. This approach provides a robust framework for validating diagnostic tests for both continuous and discrete tests in the absence of a gold standard test. Our findings can enhance our ability to design targeted disease detection strategies and implement effective control measures for brucellosis in Chinese dairy farms.

A spatiotemporal analysis of bovine brucellosis cases in Minas Gerais state, Brazil, from 2011 to 2018.

Our study explored the patterns of bovine brucellosis dissemination in Minas Gerais state, Brazil, by examining data on passive surveillance of bovine brucellosis cases from the Instituto Mineiro de Agropecuaria (IMA) (Animal Health Authority), as well as cattle population and bovine brucellosis testing, from 2011 to 2018 by means of a spatiotemporal analysis. We plotted cases, populations and testing distributions and performed spatial autocorrelation (Moran's I test) and local indicators of spatial autocorrelation (LISA) analyses. Moreover, we assessed the correlation of the spatial distribution and the compiled data (brucellosis cases, cattle populations, and brucellosis testing) by Lee's test. Our results showed that bovine brucellosis cases occurred mainly in the Triângulo Mineiro, Alto Paranaíba and Northwest regions, which reported cases in all analyzed years (2011 to 2018). The cattle population of Minas Gerais was concentrated in the same regions as bovine brucellosis cases, and the performed tests through the analyzed years (2011 to 2018). Moran's I test results of the case data showed significant spatial autocorrelation in 2011, 2015 and 2018 (p value < 0.05), and from 2011 to 2018, the population and testing data were also significant in Moran's I test (p value < 0.01). The results of cluster analysis (LISA) of cases showed clusters mainly in the Triângulo Mineiro, Alto Paranaíba, Northwest and South regions in 2011, 2015 and 2018. The local clusters for cattle populations and brucellosis testing were also observed in the same regions as bovine brucellosis cases in all years (2011 to 2018). The correlation results between clusters (Lee's test) were 0.22 (p value < 0.01) in 2011, 0.15 (p value < 0.01) in 2015 and 0.43 (p value <0.01) in 2018 between cases and populations, and 0.25 (p value <0.01) in 2011, 0.14 (p value <0.01) in 2015 and 0.38 (p value < 0.01) in 2018 for testing and cases. Therefore, our results showed that brucellosis cases were distributed together with cattle populations and brucellosis testing data, indicating that brucellosis in cattle in Minas Gerais state is being identified where there are more animals and where more tests are performed.

A study on the epidemiology of brucellosis in bovine population of peri-urban and rural areas of district Multan, southern Punjab, Pakistan.

BACKGROUND: Brucellosis is a zoonotic disease caused by a bacterial pathogen belonging to the genus Brucella. It is one of the most frequent bacterial zoonoses globally but unfortunately, it is still considered as a neglected disease in the developing world. Keeping in view, this study was conducted to determine the prevalence and risk determinants of brucellosis in large ruminants of peri-urban and rural areas of district Multan-Pakistan. For this purpose, blood samples (n = 490) were collected from the cattle (n = 245) and buffalo (n = 245) population of the study area and subjected to preliminary screening of brucellosis using local and imported RBPT reagents. All the samples were further analyzed using commercially available multi-specie indirect ELISA kit followed by their confirmation by PCR using genus and species-specific primers. Data obtained from lab analysis and questionnaires were subjected to statistical analysis for Pearson Chi-square, Odds Ratio and Confidence intervals (95%). RESULTS: The results showed that the maximum seropositivity was recorded with local RBPT reagent (VRI, Pakistan; 12.45%; 95%CI = 9.72-15.65%) followed by RBPT-IDEXX (12.24%; 95%CI = 9.52-15.45%) and RBPT-ID.vet (11.84%; 95%CI = 9.18-14.95%) however statistical difference was non-significant (P = 0.956). The ELISA results showed an overall seroprevalence rate of 11.22% (95%CI = 8.59-14.33%) with comparatively higher rate in cattle (12.65%; 95%CI = 8.82-17.44%) as compared to buffaloes (9.80%; 95%CI = 6.49-14.15%). The PCR analysis confirmed the presence of genus Brucella in all seropositive samples whereas frequency of B. abortus and B. melitensis in seropositive samples was 80% and 20%, respectively. The co-existence of both species was also observed in 5.45% samples. The statistical analysis showed a significant association of bovine brucellosis with herd size, breed, reproductive disorders, mode of insemination, educational status and farmers' awareness about brucellosis (P < 0.05). Conversely, locality, age, weight, gender, pregnancy status, parity and puberty status had no associations with brucellosis (P > 0.05). CONCLUSION: In conclusion, brucellosis is prevalent in large ruminants of district Multan, Pakistan. It is suggested to devise and implement stringent policies for the effective control and prevention of brucellosis in the region. Further, the current situation also warrants the need to strengthen interdisciplinary coordination among veterinarians and physicians in one health perspective to ensure and strengthen the human and animal health care systems in the region.

Retrospective benefit-cost analysis of bovine brucellosis control in the state of Mato Grosso, Brazil.

From 2001, due to the launching of the National Program for the Control and Eradication of Brucellosis and Tuberculosis, Brazil began a series of studies aimed at the epidemiological characterization of bovine brucellosis in its federative units. In the state of Mato Grosso, studies conducted in 2003 and 2014 showed a reduction in the prevalence of infected herds from 41.2 % to 24 % and in the prevalence of seropositive animals from 10.2 % to 5.1 %. These results stemmed from the efficient heifer vaccination program with S19 implemented by the state. From this scenario, the present study quantified and compared the benefits and costs of bovine brucellosis control in the state through a financial analysis. When considering private and public costs, the Net Present Value (NPV) was estimated at US$ 37.5 million, the Internal Rate of Return (IRR) was calculated at 31 %, and the Benefit-Cost Ratio (BCR) was 2.3. When considering only the private costs, the NPV was US$ 51.3 million, the IRR was 46 % and the BCR was 3.43, indicating that the cattle producer in Mato Grosso had a return of US$ 3.43 for each US$ 1.00 invested. Therefore, the bovine brucellosis control actions carried out in the state of Mato Grosso between 2003 and 2014 were highly advantageous from the economic point of view. The most rational way to continue decreasing bovine brucellosis prevalences at low cost in the state is to maintain the heifer vaccination program, using the RB51 vaccine in addition to S19.

Prevalence of bovine brucellosis in India: a meta-analysis.

BACKGROUND: Bovine brucellosis is a highly contagious zoonotic disease that hinders production and is a vital public health concern. Even though brucellosis is one of the important diseases in India, the exact prevalence details of the disease are not known. OBJECTIVE: To derive an estimate of the prevalence of brucellosis in India. MATERIAL AND METHODS: A systematic review and meta-analysis were carried out by using PRISMA and MOOSE protocols. A total of 133 studies were taken from online sources and various publications. Among these, 69 studies were incorporated that include a total of 140908 bovines. The data were compiled from 1990 to 2019 around India. RESULTS: Pooled estimates of the prevalence of brucellosis in cattle and buffaloes were 16.6% (95% CI: 13.0, 21.1) and 14.2% (95% CI: 8.9, 21.8), respectively and in bovines was 15.1% (95% CI: 12.0, 18.8). The meta-analysis revealed that there was significant heterogeneity between the published studies. CONCLUSION: As the prevalence of bovine brucellosis in India is not known hence the present study will provide the knowledge on prevalence and epidemiology of bovine brucellosis in India and will be helpful for the government to make policy plans to control this disease in India.

Economic analysis of bovine brucellosis control in the Rondônia state, Brazil.

Bovine brucellosis, mainly caused by Brucella abortus, is a worldwide distribution anthropozoonosis that causes great economic losses. In 2001, Brazil launched the National Program for the Control and Eradication of Brucellosis and Tuberculosis (PNCEBT). Contemporaneously, a great effort to characterize the epidemiology of the disease in Brazilian states was started. In the state of Rondônia, a first epidemiological study was carried out in 2004, revealing a prevalence of 35.2% of infected herds and 6.22% of seropositive females. In 2014, after a successful heifer vaccination program with strain 19 (S19), a second study detected a reduction in the prevalence of infected herds to 12.3% and of seropositive females to 1.9%. The present study aimed to quantify and compare the costs and benefits related to the control of bovine brucellosis in the state through an accounting analysis. Vaccinating heifers and performing serological tests to move animals were computed as private costs. The expenditures of the state official veterinary service for brucellosis control were considered public cost. The considered benefits of lowering prevalence were decreased cow replacement, decreased abortions, decreased perinatal and cow mortality, and increased milk production. Considering private and public costs, the net present value (NPV) was estimated at US$ 18.3 million, the internal rate of return (IRR) was calculated at 23%, and the benefit-cost ratio (BCR) was 1.7. When considering only the private costs, the NPV was US$34.9 million, the IRR was 49%, and the BCR was 3.0, meaning that the bovine producer had a return of 3 for each unit of currency invested. The results showed that the bovine brucellosis control measures implemented in the state of Rondônia, which had as its main strategy the vaccination of heifers with S19, produced highly advantageous economic results. The state should continue with its vaccination program, stimulating the use of the RB51 vaccine in addition to S19, to achieve further reductions in prevalence at low cost.

Seroprevalence, associated risk factors, and molecular detection of bovine brucellosis in rural areas of Egypt.

The study was carried out on six villages in northern Egypt to evaluate the epidemiological situation of bovine brucellosis among 989 unvaccinated household cattle by Rose Bengal Plate Test (RBPT) and indirect ELISA (iELISA) and to investigate the existence of Brucella DNA using real-time PCR in 100 milk and 100 sera from seropositive cattle and 50 sera from seronegative cattle. The overall seroprevalence was 20.7% and 23.7% by RBPT and iELISA, respectively. Based on the iELISA results, the seroprevalence was significantly (P < 0.05) higher in the village II (34.7%) and cattle > 7 years (30.1%). More males than females were non-significant seropositive (P = 0.6). There was 95% agreement between RBPT and iELISA, although iELISA showed a higher positivity rate (23.7%, 95% CI: 0.21-0.26) than RBPT (20.7%, 95% CI: 0.18-0.24). DNA of Brucella was confirmed in 16 milk samples by IS711 qPCR from seropositive cattle, however, no Brucella DNA was detected in serum samples tested positive and negative. Brucella abortus was the only species detected based on the alkB gene. Prevalence is highly related to the sampling site and the age of the animals. In conclusion, although qPCR is more accurate and commonly used in the diagnosis of most infectious diseases but in this situation iELISA is preferred and recommended for continuous screening and animal movement restriction and vaccination protocols, especially in high-risk areas.

Modelling the control of bovine brucellosis in India.

Brucellosis imposes substantial impacts on livestock production and public health worldwide. A stochastic, age-structured model incorporating herd demographics was developed describing within- and between-herd transmission of Brucella abortus in dairy cattle herds. The model was fitted to data from a cross-sectional study conducted in Punjab State of India and used to evaluate the effectiveness of control strategies under consideration. Based on model results, stakeholder acceptance and constraints regarding vaccine supply, vaccination of replacement calves in large farms should be prioritized. Test and removal applied at early stages of the control programme where seroprevalence is high would not constitute an effective or acceptable use of resources because significant numbers of animals would be 'removed' (culled or not used for breeding) based on false positive results. To achieve sustained reductions in brucellosis, policymakers must commit to maintaining vaccination in the long term, which may eventually reduce frequency of infection in the livestock reservoir to a low enough level for elimination to be a realistic objective. This work provides key strategic insights into the control of brucellosis in India, which has the largest cattle population globally, and a general modelling framework for evaluating control strategies in endemic settings.

Bovine brucellosis and tuberculosis at a livestock-wildlife interface in Zimbabwe: A nexus for amplification of a zoonosis or a myth?

BACKGROUND: Bovine brucellosis and tuberculosis are important zoonoses affecting both livestock and wildlife. OBJECTIVES: The study aimed to investigate seroprevalence of brucellosis and to isolate Brucella spp. and Mycobacterium bovis in cattle from livestock-wildlife interface areas. METHODS: Three sites were selected from high, medium and low interface. The high interface was adjacent to the park and separated by a broken fence, while the medium and low interface were 15-20 and 50 km from the perimeter fence, respectively. Cattle aged ≥2 years were randomly selected and bled for serology. Culture for brucellae and Mycobacterium species was attempted on lymph nodes collected at the slaughter floor. Sera were screened for Brucella antibodies using the Rose Bengal test and confirmed by the Complement fixation test. Data were analysed using a multivariable logistic regression model. RESULTS: Overall, seroprevalence was 11.7% (125/1068; 95% CI: 9.8-13.6%). High interface areas recorded significantly higher (p < 0.05) seroprevalence of 20.9% (85/406; 95% CI: 17.0-24.9%), compared to low 8.9% (31/350; 95% CI: 5.9-11.8%) and medium interface 2.9% (9/312; 95% CI: 1.0-4.8%). Brucella seropositivity was approximately three times higher (OR = 3.3, 95% CI: 2.1-5.3) for Malipati compared to Chiredzi. Similarly, the odds were twice (OR = 2.0, 95% CI: 1.2-3.5) in cows with history of abortion compared to those without. Brucella and Mycobacterium species were not isolated from all samples. CONCLUSIONS: The study highlighted the significance of high interface as a nexus for amplification of brucellosis in cattle. Thus, a brucellosis control programme that takes into consideration limiting livestock-wildlife interaction should be considered.

Deletion in KARLN intron 5 and predictive relationship with bovine tuberculosis and brucellosis infection phenotype.

Kalirin (gene: KALRN) is a Rho-GEF kinase linked to neurodegenerative diseases in humans. Unexpectedly, various polymorphisms in KALRN gene were previously associated with resistance to bacterial infections in ruminants. In this study, we evaluated the effect of the rs384223075 (RS-075) deletion in KALRN intron 5 on the occurrence of Mycobacterium bovis and Brucella abortus infections in cattle. We performed two separate case-control association analyses: one for bovine tuberculosis (bTB) using 308 Holstein and Jersey cows from three herds with prevalence between 5 and 15% for this infection; and another for brucellosis using 140 Holstein and beef crossbred cows from two herds with high prevalence for brucellosis (> 30%). In the bTB analysis, the RS-075 deletion frequency was higher among cases than controls (p = 0.0001), and the absence of the RS-075 deletion allele was associated with negative PPD-skin test results (p = 0.0009) at genotype level. On the contrary, RS-075 was not associated with Brucella spp. serological status (p = 0.72) but, unexpectedly, the deletion allele was more frequent among controls than cases in the beef crossbred herd (0.31 vs. 0.14, p = 0.02). In concordance with this observation, in vitro assays showed that the RS-075 deletion could be linked to an enhanced cellular response to bacterial antigens and unspecific stimulation in mononuclear cells derived from beef crossbred cows, specifically the reactive nitrogen species production (p = 0.008) and proliferation capacity (p = 0.018). This study is consistent with other reports that support an important role of the KALRN gene and its polymorphisms in the host response to intracellular pathogens.

Seroprevalence of brucellosis and molecular characterization of Brucella spp. from slaughtered cattle in Rwanda.

Bovine brucellosis is endemic in Rwanda, although, there is a paucity of documented evidence about the disease in slaughtered cattle. A cross-sectional study was conducted in slaughtered cattle (n = 300) to determine the seroprevalence of anti-Brucella antibodies using the Rose Bengal Test (RBT), and indirect enzyme-linked immunosorbent assay (i-ELISA). Corresponding tissues were cultured onto a modified Centro de Investigación y Tecnología Agroalimentaria (CITA) selective medium and analysed for Brucella spp. using the 16S-23S ribosomal interspacer region (ITS), AMOS, and Bruce-ladder PCR assays. The seroprevalence was 20.7% (62/300) with RBT, 2.9% (8/300) with i-ELISA, and 2.9% (8/300) using both tests in series. Brucella-specific 16S-23S ribosomal DNA interspace region (ITS) PCR detected Brucella DNA in 5.6% (17/300; Brucella culture prevalence). AMOS-PCR assay identified mixed B. abortus and B. melitensis (n = 3), B. abortus (n = 3) and B. melitensis (n = 5) while Bruce-ladder PCR also identified B. abortus (n = 5) and B. melitensis (n = 6). The gold standard culture method combined with PCR confirmation identified 5.6% Brucella cultures and this culture prevalence is higher than the more sensitive seroprevalence of 2.9%. This emphasizes the need to validate the serological tests in Rwanda. The mixed infection caused by B. abortus and B. melitensis in slaughtered cattle indicates cross-infection and poses a risk of exposure potential to abattoir workers. It is essential to urgently strengthen a coordinated national bovine brucellosis vaccination and initiate a test-and-slaughter program that is not presently applicable in Rwanda.

Development, validation and field evaluation of an indirect ELISA for the detection of antibodies against Brucella abortus in bulk and individual milk samples in dairy cattle.

Brucellosis is an abortigenic and zoonotic disease. In cattle, it is mainly caused by Brucella abortus. The disease is endemic in low- and middle-income countries, being considered a neglected zoonotic disease. In these countries, it is of high importance to develop and validate sensitive, specific and low-cost diagnostic assays for brucellosis. The aim of the present study was the development of an indirect enzyme-linked immune assay (iELISA) to detect anti-B. abortus antibodies in milk samples. We purified the lipopolysaccharide antigen from B. abortus and produced an anti-bovine IgG monoclonal antibody to develop an iELISA (iELISAINTA). The iELISAINTA was validated using 1730 bulk milk samples and 1734 individual milk samples. The sampled dairy herds had at least 3 years of consistency at their positive or negative official brucellosis status. Individual milk samples were taken in parallel with serum samples from the cows. The status of the cows was defined by the result of the complement fixation test (CFT) performed with their serum sample. The reproducibility of the assay was evaluated in two laboratories. In addition, we evaluated the performance of the assay in the field, using 4385 bulk milk samples and 968 individual milk samples. The results of the iELISAINTA were compared with those obtained using the officially accepted brucellosis techniques: iELISA from Canada (iELISACFIA) in milk samples, and the buffered plate antigen (BPA) and the CFT in serum samples. At validation, the sensitivity (Se) of the iELISAINTA in bulk milk samples was 98.61 %, and the specificity (Sp) 98.79 % with a ≥ 10 % of positivity (PP) cutoff. In individual milk samples, the Se was 98.04 %, and the Sp 98.56 % with a ≥ 16 PP cutoff. The chance-corrected agreement kappa value (κ) between the results obtained in the different laboratories was κ = 0.87. In the field evaluation, in bulk milk samples the κ value between the iELISAINTA and the iELISACFIA was κ = 0.86. On individual milk samples, the κ values were: between the iELISAINTA and the iELISACFIA κ = 0.79, between the iELISAINTA and BPA was κ = 0.85, and between the iELISAINTA and CFT κ = 0.82. The developed iELISAINTA showed a very good performance and it could be used as a screening assay for anti-B. abortus antibodies detection in individual milk samples and for epidemiologic surveillance in bulk milk samples.

Cross-Sectional Study of Seroprevalence and Associated Risk Factors of Bovine Brucellosis in Selected Districts of Jimma Zone, South Western Oromia, Ethiopia.

Bovine brucellosis is one of the most widespread but neglected zoonotic diseases in developing countries where it is an endemic and growing problem causing public health impacts. Developing a cost-effective control strategy of the disease can only be guaranteed by knowledge of the disease epidemiology that defines its risk profiles. Hence, this study was designed to evaluate epidemiological aspects of bovine brucellosis in selected districts of Jimma zone. A cross-sectional study with multistage sampling techniques was conducted on 424 cattle to evaluate its seroprevalence. Likewise, 114 households were included for the investigation of risk factors. SPSS version 20 for data analysis and C-ELISA test for antibody detection were used. Moreover, the chi-square test for univariable analysis and logistic regression model for multivariable analysis were employed to assess association between seropositivity and risk factors. From this study, 3.3% (95% CI: 1.82-5.48) and 12.3% (95% CI: 6.88-19.75) seroprevalence of the disease was detected with the highest proportion found at Kersa district (6.5 (95% CI: 1.37-17.90) and (21.4 (95% CI: 4.66-50.80)) followed by Seka Chokorsa (1.76 (95% CI: 0.37-5.07) and (6.7 (95% CI: 1.40-18.27)) and Mana (1.75 (95% CI: 0.21-6.20) and (7.1 (95% CI: 0.88-23.50)) at individual animals and herd levels, respectively. Cattle of poor body condition, pregnant, and cows with history of abortion and repeat breeding were found 4.8 (95% CI: 2.00-22.74), 4.3 (95% CI: 1.43-13.04), 3.3 (95% CI: 1.07-10.21), and 2.7 (95% CI: 1.86-8.15) times more likely seropositive than their counterparts, respectively. Besides these, mixed feeding style was highly associated with seropositive reactors than separate feeding (AOR = 8.3; 95% CI: 1.76-38.99). These findings depicted substantial areas to be addressed in implementation of appropriate and immediate control actions and establishment of intervention mechanisms of bovine brucellosis.

A comparison of logistic regression and classification tree to assess brucellosis associated risk factors in dairy cattle.

Machine learning approaches have been increasingly utilized in the field of medicine. Brucellosis is one of the most common contagious zoonotic diseases with significant impacts on livestock health, reproduction, production, and public health worldwide. Therefore, our objective was to determine the seroprevalence and compare the logistic regression and Classification and Regression Tree (CART) data-mining analysis to assess risk factors associated with Brucella infection in the densest cattle populated Egyptian governorates. A cross-sectional study was conducted on 400 animals (383 cows, 17 bulls) distributed over four Governorates in Egypt's Nile Delta in 2019. The randomly selected animals from studied geographical areas were serologically tested for Brucella using iELISA, and the animals' information was obtained from the farm records or animal owners. Eight supposed risk factors (geographic location, gender, herd size, age, history of abortion, shared equipment, and disinfection post-calving) were evaluated using multiple stepwise logistic regression and CART machine-learning techniques. A total of 84 (21.0%; 95% CI 17.1-25.3) serum samples were serologically positive for Brucella. The highest seroprevalence of Brucella infection was reported among animals raised in herd size > 100 animals (65.5%), with no disinfection post-calving (61.7%), with a history of abortion (59.6%), and with shared equipment without thorough cleaning and disinfection (57.1%). The multiple stepwise logistic regression modeling identified herd size, history of abortion, and disinfection post-calving as important risk factors. However, CART modeling identified herd size, disinfection post-calving, history of abortion, and shared equipment as the most potential risk factors for Brucella infection. Comparing the two models, CART model showed a higher area under the receiver operating characteristic curve (AUROC = 0.98; 95% CI 0.95 - 1.00) than the binary logistic regression (AUROC = 0.89; 95% CI 0.73 - 0.92). Our findings strongly imply that Brucella infection is most likely to spread among animals raised in large herds (>100 animals) with a history of abortions and bad hygienic measures post-calving. The CART data-mining modeling provides an accurate technique to identify risk factors of Brucella infection in cattle.

Análise da correlação dos índices de estrutura e recursos humanos do serviço veterinário oficial em 2019 e as incidências acumuladas (2017 ­ 2019) de doenças de notificação obrigatória em bovinos e equinos no Brasil / Analysis of the correlation between the structure and human resources indexes of the official veterinary service in 2019 and the accumulated incidences (2017 ­ 2019) of notifiable diseases in cattle and horses in Brazil

As doenças de notificação obrigatória em bovinos podem gerar impactos sociais e econômicos significativos na cadeia pecuária brasileira, além de consequências negativas no mercado internacional devido a embargos sanitários. Para auxiliar no entendimento de como um sistema de vigilância epidemiológica com mais recursos pode gerar mais credibilidade para o país, foram realizadas análises de correlação entre a notificação de doenças e a estrutura veterinária disponível nos Órgãos Executores de Sanidade Agropecuária (OESAs), a partir dos dados contidos no Sistema Nacional de Informação Zoossanitária (SIZ), entre os anos de 2017 e 2019. Com base nos dados do serviço veterinário, foram produzidos o Índice de Estrutura Física Oficial (IEFO) e o Índice de Recursos Humanos do Serviço Oficial (IRHSO). Foi realizada análise de correlação entre a notificação de doenças de bovinos com a capacidade de estrutura física e recursos humanos de vigilância epidemiológica disponíveis no Serviço Veterinário brasileiro. Os estados AP, RR e SC foram os que mais notificaram brucelose e tuberculose no período e estão entre os melhores índices de estrutura e recursos humanos do país. A análise dos índices mostrou que a raiva não possui correlação significativa com estrutura e recursos humanos do serviço, entretanto, brucelose e tuberculose possuem correlação positiva com estrutura veterinária oficial disponível para a vigilância em bovinos. Portanto, melhorias na estrutura podem refletir no incremento dos índices de notificação das doenças de bovinos, assim como na qualidade de suas informações.

Notifiable diseases in cattle can generate significant social and economic impacts on the Brazilian livestock chain, in addition to impacts on the international market due to sanitary embargoes. To help understand how an epidemiological surveillance system with more resources can generate more credibility for the country, correlation analyzes were carried out between the notification of diseases and the veterinary structure available in the Executing Bodies of Agricultural Health (OESAs), based on the data contained in the National System of Zoosanitary Information (SIZ), between the years 2017 to 2019. Based on public data from the veterinary service, the Official Physical Structure Index (IEFO) and the Official Service Human Resources Index (IRHSO) were produced. Correlation analysis was performed between the notification of bovine diseases with the capacity of physical structure and human resources for epidemiological surveillance available in the Brazilian Veterinary Service. AP, RR and SC were the states that most notified brucellosis and tuberculosis in the period and are among the best indices of structure and human resources in the country. The analysis of correlation indices showed that the rabies disease does not have a significant correlation with the structure and the human resources of the service, however, brucellosis and tuberculosis does have a positive correlation with the official veterinary structure available for surveillance in cattle. Therefore, Improvements in the structure can reflect in the increase of the notification rates, as well as in the quality of its information.

Evaluation of diagnostic tests' sensitivity, specificity and predictive values in bovine carcasses showing brucellosis suggestive lesions, condemned by Brazilian Federal Meat Inspection Service in the Amazon Region of Brazil.

Cervical bursitis is a suggestive lesion of bovine brucellosis. Diagnostic sensitivity and specificity of two brucellosis serological tests, Rose Bengal (RB) and serum agglutination test with 2-mercaptoethanol (SAT/2-ME), and of isolation and identification (bacteriology) were evaluated through Bayesian latent class analysis (BLCA). A total of 165 paired serum and cervical bursitis samples detected at inspection by Brazilian federal meat inspection services were analyzed. The best model fit to the data occurred when accounting for the conditional dependence between serological tests. According to this model, RB and SAT/2-ME had almost the same sensitivity, 0.960 [0.903 - 0.992] and 0.963 [0.906 - 0.994] with 95 % Credible Interval (95 %CrI), respectively. Specificities were 0.9068 [0.562 - 0.997] and 0.875 [0.546 - 0.990] for RB and SAT/2-ME, respectively, also with 95 %CrI. Bacteriology had lower sensitivity than serological tests, 0.594 (95 %CrI: [0.525 - 0.794]) and the highest specificity of all evaluated tests, 0.992 (95 %CrI: [0.961-1.00]). Prevalence of infected animals was 0.829 (95 %CrI: [0.700-0.900]). BLCA showed that both RB and SAT/2-ME fitted to the purpose of initial screening the brucellosis suspect in carcasses with cervical bursitis in a reliable way. The results of RB or SAT/2-ME can guide the sanitary actions for brucellosis control and help the implementation of a risk-based surveillance system in the meat production chain. This strategy is especially true in remote areas with large beef cattle herds, raised extensively, where in vivo tests are rarely performed due to logistic and management constraints, as in the Northern region of Brazil.

Cross-sectional study of Brucella spp. using real-time PCR from bovine whole blood in Colombia.

A cross-sectional study was conducted in Colombia to recover Brucella spp. DNA from bovine whole-blood samples through probe-based real-time PCR (qPCR). By an SNP-based assay, vaccine strains were differentiated from field strains. The associated factors were evaluated using logistical regression models. A total of 656 random cows from 40 herds were selected and analyzed using serology and PCR. The qPCR assay detected 9.5% (n = 62/656; 95% CI: 7.3, 12.0) of the animals with Brucella-DNA presence, while the serological test detected a 6.6% (n = 43/656; CI: 4.8, 8.7). 62.5% (n = 25/40; 95% CI: 45.8, 77.3) of positive cases were detected at the herd-level by the qPCR, while only 27.5% (n = 11/40; 95% CI: 14.6, 43.9) were detected by the serological test. All positive samples were identified as field Brucella strains employing the SNP-based assay. In the final regression model at the animal-level, five variables were associated with Brucella-DNA presence: the use of bulls for mating recorded history of reproductive problems, pregnant cows, parlor milking, and cows belonging to farms ≤200 m from the main road. At the herd-level, two variables were associated with Brucella-DNA presence: recorded history of reproductive problems and the use of bulls for mating. Given the fluctuant brucellosis prevalence in endemic areas, updated epidemiological studies are necessary to evaluate the disease dynamic and if established prevention and control measures have been effective or need to be adjusted. The increase in the prevalence of brucellosis in animal reservoirs creates an important risk of transmission in humans.

Seroprevalence and risk factors for bovine brucellosis in the state of Paraná, Brazil: an analysis after 18 years of ongoing control measures.

Seroprevalence and risk factors of bovine brucellosis (Brucella abortus) in herds and cattle were estimated by a cross-sectional study in the state of Paraná, Brazil. The state was divided into seven regions and a random, two-stage sampling was performed on properties and cattle from each region between 2018 and 2019. Serum samples were collected from 11,592 cows over 24 months from 1,757 properties and a questionnaire was applied to identify potential risk factors. As recommended by the National Program for the Control and Eradication of Animal Brucellosis and Tuberculosis (PNCEBT), serological testing for the detection of anti-Brucella antibodies included the buffered plate agglutination test (screening test) and the fluorescence polarization assay (confirmatory test). The seroprevalence of bovine brucellosis on properties and in cattle was 4.87% (95% confidence interval [CI]: 3.98-5.93%) and 2.24% (95% CI: 1.47-3.41%), respectively. Multiple logistic regression analysis identified larger herd size and failure to test for brucellosis as risk factors for the presence of anti-B. abortus antibodies. These results demonstrate no change in the prevalence when comparing initial studies conducted in 2002. Given our findings, it is recommended that policies for brucellosis control include a widespread vaccination program for higher prevalence areas and eradication approach to lower prevalence areas. All steps related to correct immunization of the herds should be verified and improved by training and education. Health education action must be carried out informing farmers about the risks of introducing animals not tested for brucellosis into their herds and the benefits of testing their herds regularly.

Epidemiology of bovine brucellosis in Hisar, India: identification of risk factors and assessment of knowledge, attitudes, and practices among livestock owners.

Brucellosis caused by facultative intracellular bacteria, Brucella, remains a global threat to both animal and human health. In this study we aimed to identify potential risk factors of bovine brucellosis and to assess the knowledge, attitudes, and practices (KAPs) of livestock keepers in Hisar, India. A standardized questionnaire was used to collate information regarding potential risk factors of bovine brucellosis and livestock owners' KAPs. A total of 127 livestock keepers were involved. Serum samples from their animals (n = 635) were tested for the presence of antibodies against Brucella by Rose Bengal Plate Test (RBPT) and indirect enzyme-linked immunosorbent assay (iELISA). Out of these, 78 (61.4%) of the herds had at least one seropositive animal, and 302 (47.6%) of the cattle were seropositive. Univariate and multivariate analysis revealed significant associations between intensive farm type (OR = 4.6; 95% CI, 1.6-16.7; P = 0.009), hygienic disposal of aborted fetuses (OR = 0.3; 95% CI, 0.08-0.9; P = 0.04) and herd seropositivity for brucellosis. The majority, 96 (75.6%) of the respondents, were males aged 18-50, and 82 (64.6%) owned a small-backyard farm. Only 51 (40.2%) of the participants knew about brucellosis; out of them, 54.9% (28/51) could not identify clinical signs of brucellosis. Six (11.8%) participants indicated abortion as the most noticeable clinical sign, and 45.1% indicated that consumption of raw milk is associated with high risk of contracting brucellosis. A large proportion of respondents confirmed that milk from their animals was regularly consumed (86.6%) and sold (59.8%) to other people. These results suggest that bovine brucellosis is endemic in Haryana, where Brucella-contaminated milk is likely being regularly sold. Brucellosis control efforts in Haryana should include education programs to raise awareness of the disease and means to control it in cattle and to prevent zoonotic transmission.

Documenting the absence of bovine brucellosis in dairy cattle herds in the southern region of Malawi and the associated knowledge, attitudes and practices of farmers.

There is paucity of Brucella prevalence data in Malawi. For this reason, a cross-sectional study was conducted, from 06 January 2020 to 27 February 2020, to estimate the seroprevalence of brucellosis in dairy cattle herds amongst smallholder farmers, government and private dairy farms in the southern region. A total of 529 serum samples were screened for anti-Brucella antibodies using the Rose Bengal test (RBT) and a competitive enzyme-linked immunosorbent assay (cELISA). A pre-tested electronic (Epicollect tool, Wellcome Sanger Institute, United Kingdom) questionnaire was administered to 378 smallholder farmers to assess their knowledge, attitudes and practices towards brucellosis. Descriptive statistics were used to analyse the data in Microsoft Excel® and Statistical Package for Social Sciences (SPSS®) version 21. No animal tested positive for presence of anti-Brucella antibodies, indicating 0% prevalence (individual and herd levels). The majority (94.2%; 95% confidence interval [CI]: 91.8-96.5) of smallholder farmers had never heard about brucellosis. Furthermore, assisting during parturition without protective equipment (41.3%; 95% CI: 36.3-46.2) and using bulls for breeding (75%; 95% CI: 70.2-78.9) were amongst the common risk practices that were identified. We could not detect brucellosis in this study that indicates the disease could be very rare or even absent in the dairy cattle herds of the southern region of Malawi. However, further Brucella studies need to be conducted in cattle, small livestock, wildlife and humans to document the true status of brucellosis in the country. Brucellosis surveillance, monitoring, awareness and preventive measures are required to maintain this favourable situation.