Prevalence and risk-mapping of bovine brucellosis in Maranhão State, Brazil

Unveiling the epidemiology and community perspectives on bovine brucellosis in North Shewa, Central Highlands of Ethiopia

Brucellosis is a bacterial disease of many domestic and wild animals with great economic and public health importance. Although it has a major constraint in dairy production, comprehensive information regarding the epidemiology of brucellosis in dairy herds is limited. Besides, evaluating the dairy farmers' knowledge, attitude, and practice (KAP) regarding brucellosis is crucial for generating information that can enhance control programs and public health interventions. Thus, this study aims to investigate the seroepidemiology of brucellosis and evaluate the dairy farmers' KAP in North Shewa, central highlands of Ethiopia. A total of 511 blood samples were randomly collected from 142 dairy herds. Rose Bengal plate test (RBPT) was used for primary screening, and a complement fixation test (CFT) was conducted on RBPT-positive samples. Retrospective information was collected to associate brucellosis with a history of reproductive disorders. A questionnaire survey assessed farmers' knowledge, attitudes, and practices regarding zoonotic brucellosis. Multivariable Firth's bias-reduced logistic regression model was used to identify factors associated with brucellosis seropositivity. The overall seroprevalence of brucellosis was 0.98% (95% CI: 0.41-2.34%) at the animal level and 3.52% (95%CI: 1.46-8.26%) at the herd level. Cows older than 6 years were four times more likely to be seropositive (OR = 3.82; 95% CI: 1.71-7.97; P = 0.004), while local breeds had a six-fold higher risk (OR = 6.2; 95% CI: 2.08-8.21; P = 0.016). Cattle with a history of abortion (OR = 22.35; 95% CI: 3.90-107.91; P = 0.002) and retained fetal membrane (OR = 18.74; 95% CI: 3.48-63.86; P = 0.020) showed significantly higher seroprevalence. A survey of 120 respondents found that 86% were unaware of zoonotic brucellosis, 74.63% assisted cows during the parturition without protective equipment, and 64% consumed raw meat. Only 9.17% disposed of fetal membranes and aborted fetuses properly. This study revealed evidence of brucellosis in 4% of dairy herds, poor understanding of the disease, various risky practices, and poor biosafety measures. Thus, educating dairy farmers and implementing strict farm biosecurity measures are essential steps to minimize the impacts of the disease on the growing dairy industry and public health.

Aspects of brucellosis vaccination in Maranhão state

Bovine brucellosis is a zoonosis of great economic and public health relevance. Understanding the epidemiological aspects of this disease is a determining factor to help developing effective strategies and supporting decision-making processes. The aim of the present study is to carry out a situational vaccination diagnosis against brucellosis in Maranhão State's cattle in order to identify challenges set for vaccination operations and to help the Official Veterinary Service to plan health interventions. In 2022, questionnaires focused on the socioeconomic profile and knowledge on vaccination were applied to the following groups to help achieving the aforementioned aims: (i) cattle breeders (n = 201), (ii) veterinarians registered with the National Program for Control and Eradication of Brucellosis and Animal Tuberculosis (n = 84), (iii) Official Veterinary Service servants involved in conducting the National Program for Control and Eradication of Brucellosis and Animal Tuberculosis (n = 75), and (iv) individuals in charge of vaccine retail outlets (n = 58). Farmers and those in charge of vaccine retail outlets presented average knowledge on this subject (51-70% accuracy). Yet, there were similar knowledge gaps in these two groups. Although the knowledge level recorded for registered veterinarians and Official Veterinary Service servants was high (71-100% accuracy), low adherence to personal protection equipment was also observed, and it is worrisome, given brucellosis' zoonotic nature. In addition, veterinarians presented knowledge gaps when it comes to updates on the National Program for Control and Eradication of Brucellosis and Animal Tuberculosis Technical Regulations, and it can be an indicative that questionnaires were superficially or carelessly answered. Other obstacles to vaccination were poor quality of roads to access properties and breeders with limited number of bred calves in the age group 3 to 8 months. These barriers impair the expansion of vaccination cover against brucellosis in Maranhão State. The Official Veterinary Service must implement a strategic plan to fill out the knowledge gaps shown by those in this production chain and make it easier to get to the basis for effective health interventions aimed at brucellosis control in Maranhão State.

Distribution, seroprevalence and risk factors for bovine brucellosis in Brazil: Official data, systematic review and meta-analysis

Bovine brucellosis is an endemic disease in Brazil, and evidence-based assessments of the available literature on its seroprevalence and risk factors are limited. The aim of this study was to systematically review and summarize studies related to seroprevalence and risk factors of bovine brucellosis in the entire Brazil, in addition to comparing published data with the most recent official reports. Articles available in scientific databases and published between October 2006 and October 2021 were evaluated. Forty-five publications were included in the meta-analysis on the seroprevalence of brucellosis and 29 publications in the review on risk factors. The largest number of publications was found for the State of Mato Grosso do Sul (n=4), and the highest and lowest seroprevalences were observed in Acre (11%; 95% CI: 8.0-14.0%) and in the Federal District (0.4%; 95% CI: 0.2-0.7%). The main risk factors were the purchase of animals for breeding, vaccination, the number of heifers (female ≥2 years), the presence of calving paddocks and the occurrence of abortions. The need for new official studies has been suggested to determine the true prevalence of bovine brucellosis in Brazil, supported by the National Program for the Control and Eradication of Animal Brucellosis and Tuberculosis.

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.

A systematic review and meta-analysis of bovine brucellosis seroprevalence in Latin America and the Caribbean

Introduction

Bovine brucellosis is a significant public health problem in countries with economic and zoonotic implications. Although relevant, there are no previous systematic reviews about bovine brucellosis in Latin America.

Methods

We performed a systematic literature review in five data-bases to assess the seroprevalence of Brucella in cattle. A meta-analysis with a random-effects model was performed to calculate the pooled prevalence and 95% confidence intervals (95%CI). In addition, measures of heterogeneity (Cochran's Q statistic and I2 test) were reported.

Results

The literature search yielded 3,403 articles, of which 65 studies were fully valid for analysis. The pooled seroprevalence for Brucella in bovine (n ​= ​46,883,177) was 4.0% (95%CI: 3.0%-5.0%; p ​< ​0.001), and Venezuela was the country with the highest prevalence (16.0%). By regions, the highest seroprevalence is in Central America and the Caribbean islands (8.0%,95%CI: 3.0%-15.0%; p ​< ​0.001, I2 ​= ​99.85).

Conclusions

Some countries reported still relevant seroprevalences of bovine brucellosis, especially at the Central America and Caribbean islands. Multiple factors may influence the survival and spread of pathogens in the environment; farms located in regions bordering forest areas, in areas of difficult access to the veterinary service; extensive beef herds raised at pastures with different age and productive groups inter-mingled, and minimal concerns regarding hygiene practices and disease prevention measures. Bovine brucellosis has not been eliminated and needs to be considered with new tools for prevention and control, especially being a zoonosis.

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.

Sero-prevalence and risk factors associated with brucellosis in dairy cattle of Sylhet District, Bangladesh: A cross-sectional study

BACKGROUND

Brucellosis is an emerging disease that causes a significant impact on productive and reproductive performance in dairy cattle. Though Brucella is a pivotal microorganism for dairy cattle, the scenario of brucellosis in Sylhet District is unknown.

OBJECTIVES

A cross-sectional study was carried out to assess the prevalence and determinants associated with brucellosis in dairy cattle of Sylhet District.

METHODS

A total of 386 sera and data on determinants from 63 dairy herds were collected from 12 sub-districts using simple random sampling. The sera were tested with Rose Bengal Brucella antigen test, Brucella abortus plate agglutination test and serum agglutination test to find out the sero-positivity.

RESULTS

Overall, 17.09% (95% CI: 13.67-21.18) prevalence in cows were calculated. Relatively higher prevalence (56.08%; 95% CI: 42.23-70.32) was recorded in cows having parity ≥4 and were at higher risk (OR = 7.28) than the other cows with parity 0-3. Prevalence was significantly higher in cows with history of abortion 90.63% (95% CI: 75.79-96.76), repeat breeding 79.17% (95% CI: 65.74-88.27) and reproductive abnormalities 48.54% (95% CI: 39.12-58.07). Farm-level prevalence was high in farms with the previous history of abortion 95.45% (95% CI: 78.20-99.19) and repeat breeding 90.00% (95% CI: 74.38-96.54).

CONCLUSIONS

The prevalence was high in Sylhet district, which might be a public health concern. Therefore, this study would represent the baseline information for guiding brucellosis control and prevention.

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.

Bovine Brucellosis: Epidemiology, Public Health Implications, and Status of Brucellosis in Ethiopia

Brucellosis is a globally distributed zoonotic disease that causes serious problems in developing countries such as Ethiopia. Brucella abortus is the primary cause of brucellosis in cattle, and Brucella melitensis and Brucella suis also occasionally cause Brucella infection in cattle. Abortion and the retained fetal membrane are typical signs in females, whereas orchitis and bursitis are the known signs in male cattle. Brucellosis is typically transmitted to healthy cattle by direct or indirect contact with diseased cattle or their discharges. Humans can acquire brucellosis through the consumption of unpasteurized milk or milk products, and through contact with diseased cattle or their discharges. The occurrence of bovine brucellosis is affected by different factors related to the management system, host, and environmental factors. In Ethiopia, the occurrence of brucellosis is high in pastoral and mixed cattle management systems, wherever humans live closely with cattle and so have a higher probability of picking up the Brucella organism. The most suitable technique in the management of Brucella infection is the vaccination of young female cattle. Brucella abortus can also be eradicated by the isolation of diseased cattle, administration of immunizing agents, and test-and-slaughter methods. Therefore, it is important to implement applicable management techniques and to increase public awareness about the transmission of brucellosis, and further research should be conducted on brucellosis in high-risk groups.

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.

Use of a generalized additive model for a spatial analysis of bovine brucellosis risk in the state of Mato Grosso in 2002 and 2014

Diseases that affect cattle represent obstacles to the development of livestock activity. Brucellosis is a significant such disease because it is transmissible, has a chronic nature, and causes health and economic damages to the herd and rural producer. Data from surveys performed in 2002 and 2014 were compared to identify the spatial distribution of bovine brucellosis and to evaluate clusters of outbreaks and areas of greater risk to have infected cattle in the state of Mato Grosso, Brazil. The present study analyzed the data obtained in the aforementioned investigations with a statistical model based on a spatial point process called a generalized additive model (GAM). The analysis made it possible to identify the regions of highest and lowest risk in the state of Mato Grosso. Of the 1001 properties analyzed in 2002, 198 were in areas with high-odds ratio, and 121 were in a low-odds ratio area. Of the 1248 properties sampled in 2014, 119 were in a high-odds ratio area, and 162 were in a low-odds ratio area. Areas with high-odds ratio are more likely to have infected cattle and can be considered to be at higher risk for the disease. The results of the present study highlight the reduction in foci, prevalence, and its relationship with the spatial distribution of bovine brucellosis. The study results should help the official defense service of Mato Grosso direct its activities according to the profile of each region.

Bovine brucellosis in slaughterhouses controlled by Federal and Municipal Inspection Services in the state of Maranhão, Brazil

ABSTRACT: The aims of the current study were to investigate the prevalence of bovine brucellosis, to correlate laboratory results of serum reactive samples to the serology of animals presenting serous pouches, and to identify possible risk factors for the development of the disease. In order to do so, 1,265 bovine blood samples were collected from male and female animals bred in different counties in Maranhão state, Brazil, and in other regions of the country. The animals were slaughtered in two slaughterhouses controlled by the Federal Inspection Service (FIS), and in two others controlled by the Municipal Inspection Service (MIS), of regions such as Açailândia and Imperatriz. Samples were tested for specific antibodies by using buffered acidified antigen (BAA) and 2-mercaptoethanol in combination with slow serum agglutination (2-ME + SSA). Additionally, an epidemiological questionnaire was applied to 100 owners, who provided animals to the slaughterhouses, to enable investigating the risk factors for bovine brucellosis. Fifteen serous pouches of animals presenting this lesion were also collected at slaughter time. Thirty-nine out of the analyzed samples were reacted to BAA, whereas 15 reacted to the 2-ME + SSA test; only one male was reagent and it resulted in 1.19% prevalence. One out of the 15 collected serous pouches reacted to the 2-ME + SSA test. The risk factors identified in this study were: the incidence of miscarriages, the sale of animals without previous examination, and the failure in testing the animals before introducing them in herds and before slaughter. It was possible to conclude that the animals slaughtered in the herein evaluated slaughterhouses were infected with Brucella abortus, as well as that this infection prevailed in females.

Outbreak of human brucellosis in Southern Brazil and historical review of data from 2009 to 2018

Background

Human brucellosis (HB) is a bacterial zoonosis that is more frequent in low income and middle-income countries; it is sometimes associated with outbreaks. The aim of this study was to describe the largest outbreak of HB in Brazil.

Methods

A retrospective cohort study of patients suspected of having contracted HB in the state of Paraná, Southern Brazil from January 2009 to January 2017. Following an outbreak of 51 cases of HB in a slaughterhouse at Paiçandu in 2014, HB was defined as an obligatory reportable disease in the State. Diagnostic tests for HB included serum agglutination, ELISA (IgG or IgM) and polymerase chain reaction (PCR). Clinical, laboratorial and epidemiological data were analyzed. A P value of 0.05 was considered statistically significant.

Results

Out of a total of 3,941 patients, 754 presented with a positive test result for HB. After 2014, there was a significant increase in the number of cases, exceeding 100 cases per trimester. In the beginning of 2015, the workgroup of HB started several actions for prevention and treatment, and the number of cases progressively diminished to fewer than 20 cases per trimester. Of 191 reported cases, an occupational risk was found in 84.7%; most cases occurred in farmers (60.0%), veterinarians (17.6%) and slaughterhouse workers (14.7%). Manipulation of animals and unpasteurized milk consumption were associated with positive Brucella IgM ELISA with an odds ratio (OR) of 1.42 (1.09–1.84) and 1.48 (1.01–2.15), respectively.

Conclusions

HB outbreaks can occur in low to middle-income countries and are associated with slaughterhouse work, handling of unpasteurized milk and animal manipulation. Intensive programs for control of HB are important to reduce the number of cases.

Human brucellosis (HB) is a bacterial zoonosis more frequent in low income and middle-income countries. The number of cases has increased in Southern Brazil since 2014. Considering the risk of dissemination of the disease, the authors evaluated the whole spectrum of the disease in the State of Paraná, where cases were reported. More than 3,500 patients at risk for the disease were evaluated and 754 presented with positive blood test results for human brucellosis. The local Health Agency established a program of brucellosis treatment and prevention in the following year. After the intensive control program, there was a significant reduction in the number of HB cases.

Individual-based modelling and control of bovine brucellosis

We present a theoretical approach to control bovine brucellosis. We have used individual-based modelling, which is a network-type alternative to compartmental models. Our model thus considers heterogeneous populations, and spatial aspects such as migration among herds and control actions described as pulse interventions are also easily implemented. We show that individual-based modelling reproduces the mean field behaviour of an equivalent compartmental model. Details of this process, as well as flowcharts, are provided to facilitate the reproduction of the presented results. We further investigate three numerical examples using real parameters of herds in the São Paulo state of Brazil, in scenarios which explore eradication, continuous and pulsed vaccination and meta-population effects. The obtained results are in good agreement with the expected behaviour of this disease, which ultimately showcases the effectiveness of our theory.

Evaluation of the cost-effectiveness of bovine brucellosis surveillance in a disease-free country using stochastic scenario tree modelling

Surveillance systems of exotic infectious diseases aim to ensure transparency about the country-specific animal disease situation (i.e. demonstrate disease freedom) and to identify any introductions. In a context of decreasing resources, evaluation of surveillance efficiency is essential to help stakeholders make relevant decisions about prioritization of measures and funding allocation. This study evaluated the efficiency (sensitivity related to cost) of the French bovine brucellosis surveillance system using stochastic scenario tree models. Cattle herds were categorized into three risk groups based on the annual number of purchases, given that trading is considered as the main route of brucellosis introduction in cattle herds. The sensitivity in detecting the disease and the costs of the current surveillance system, which includes clinical (abortion) surveillance, programmed serological testing and introduction controls, were compared to those of 19 alternative surveillance scenarios. Surveillance costs included veterinary fees and laboratory analyses. The sensitivity over a year of the current surveillance system was predicted to be 91±7% at a design prevalence of 0.01% for a total cost of 14.9±1.8 million €. Several alternative surveillance scenarios, based on clinical surveillance and random or risk-based serological screening in a sample (20%) of the population, were predicted to be at least as sensitive but for a lower cost. Such changes would reduce whole surveillance costs by 20 to 61% annually, and the costs for farmers only would be decreased from about 12.0 million € presently to 5.3–9.0 million € (i.e. 25–56% decrease). Besides, fostering the evolution of the surveillance system in one of these directions would be in agreement with the European regulations and farmers perceptions on brucellosis risk and surveillance.

Epidemiology of bovine brucellosis in Costa Rica: Lessons learned from failures in the control of the disease

Brucellosis, caused by Brucella abortus is a major disease of cattle and a zoonosis. In order to estimate the bovine brucellosis prevalence in Costa Rica (CR), a total 765 herds (13078 bovines) from six regions of CR were randomly sampled during 2012-2013. A non-random sample of 7907 herds (532199 bovines) of the six regions, arriving for diagnoses during 2014-2016 to the Costa Rican Animal Health Service was also studied. The prevalence estimated by Rose Bengal test (RBT) ranged from 10.5%-11.4%; alternatively, the prevalence estimated by testing the RBT positives in iELISA, ranged from 4.1%-6.0%, respectively. However, cattle in CR are not vaccinated with B. abortus S19 but with RB51 (vaccination coverage close to 11%), and under these conditions the RBT displays 99% specificity and 99% sensitivity. Therefore, the RBT herd depicted in the random analysis stands as a feasible assessment and then, the recommended value in case of planning an eradication program in CR. Studies of three decades reveled that bovine brucellosis prevalence has increased in CR. B. abortus was identified by biochemical and molecular studies as the etiological agent of bovine brucellosis. Multiple locus variable-number tandem repeat analysis-16 revealed four B. abortus clusters. Cluster one and three are intertwined with isolates from other countries, while clusters two and four have only representatives from CR. Cluster one is widely distributed in all regions of the country and may be the primary B. abortus source. The other clusters seem to be restricted to specific areas in CR. The implications of our findings, in relation to the control of the disease in CR, are critically discussed.

The application of epidemiology in national veterinary services: Challenges and threats in Brazil

The application of epidemiology in national veterinary services must take place at the interface between science and politics. Animal health policy development and implementation require attention to macro-epidemiology, the study of economic, social and policy inputs that affect the distribution and impact of animal or human disease at the national level. The world has changed fast over the last three decades including the delivery of veterinary services, their remit and the challenges addressed by public and animal health policies. Rethinking the role of public services and how to make public programs more efficient has been at the heart of the political discussion. The WTO through its SPS Agreement has changed the way in which national veterinary services operate and how trade decisions are made. Most low and middle income countries are still struggling to keep up with the new international scene. Some of these countries, such as Brazil, have very important livestock industries and are key to the global food systems. Over the last two decades, Brazil became a leading player in exports of livestock products, including poultry, and this created a strong pressure on the national veterinary services to respond to trade demands, leading to focus animal health policies on the export-driven sector. During the same period, Brazil has gone a long way in the direction of integrating epidemiology with veterinary services. Epidemiology groups grew at main universities and have been working with government to provide support to animal health policy. The scope and quality of the applied epidemiological work improved and focused on complex data analysis and development of technologies and tools to solve specific disease problems. Many public veterinary officers were trained in modern epidemiological methods. However, there are important institutional bottlenecks that limit the impact of epidemiology in evidence-based decision making. More complex challenges require high levels of expertise in veterinary epidemiology, as well as institutional models that provide an appropriate environment for building and sustaining capacity in national veterinary services. Integrating epidemiology with animal health policy is a great opportunity if epidemiologists can understand the real issues, including the socio-economic dimensions of disease management, and focus on innovation and production of knowledge. It may be a trap if epidemiologists are restricted to answering specific decision-making questions and policy makers perceive their role exclusively as data analysts or providers of technological solutions. Fostering solutions for complex issues is key to successful integration with policy making.

Large-scale study of herd-level risk factors for bovine brucellosis in Brazil

Bovine brucellosis is an important zoonosis caused by Brucella abortus that negatively impacts livestock productivity. In 2001, Brazil launched a new national program aimed at eradicating animal brucellosis that included large-scale studies of the prevalence and risk factors to support strategic decision-making. These studies were implemented by the animal health authorities and were underpinned by the scientific coordination of the University of São Paulo and the University of Brasília. The state-level results were published and revealed important differences in herd prevalence among regions. The risk factors varied across states and did not clearly explain the observed spatial disease spread. This study used a consolidated herd-level database of 14 states and 17,100 herds, from the prevalence surveys' data, to gain insights into herd profiles and cattle production practices that might be associated with the risk of brucellosis. At the time of data collection, the study area comprised just over 56 million bovine females aged over 24 months and approximately 1.8 million herds. After an exploratory univariable analysis, all factors with p≤0.20 were included in a multiple logistic regression model, using the design-based method in order to take herd sampling weights into account. The number of females in the herd markedly increased the risk of infection; compared with smaller herds (less than 30 females), the odds ratio was 3.42 [CI 95% 2.98-3.91] for herds with 31 to 100 females, 5.68 [4.92-6.55] for herds with 101 to 400 females, and 13.14 [10.94-15.78] for herds with more than 400 females. The risk was higher for extensive cattle production farms (OR=1.23 [1.07-1.42]) and for farms that purchased replacement stock from cattle traders (OR=1.27 [1.08-1.47]) or directly from other farms (OR=1.19 [1.07-1.32]). The exclusive use of artificial insemination (OR=0.57 [0.4-0.81]) and regular veterinary support (OR=0.68 [0.6-0.77]) appeared to be protective factors. These findings are consistent with the regional prevalence trends observed in the study and provide key guidance for the planning of the national effort to control and eradicate brucellosis. High vaccination coverage of heifers is recommended, especially when targeted to areas where large-scale extensive cattle production predominates. The smaller, more intensive herds, are good candidates for disease accreditation schemes.

Frequência de brucelose bovina em rebanhos leiteiros e em seres humanos na região central do estado do Maranhão, Brasil

RESUMO: Objetivou-se com este estudo estimar a frequência da brucelose em bovinos e em ordenhadores na região central do Maranhão. Foram escolhidas, no período de maio a outubro de 2013, de forma aleatória, 35 propriedades cadastradas na Agência Estadual de Defesa Agropecuária do Maranhão (AGED-MA) e analisados sorologicamente 525 bovinos com aptidão leiteira, hemossoros de 60 ordenhadores, além de ter sido aplicado questionário epidemiológico para investigar os fatores de risco associados à infecção. O protocolo de diagnóstico utilizado foi o teste de triagem com antígeno acidificado tamponado (AAT), e a confirmação dos reagentes ocorreu mediante os testes 2-mercaptoetanol (2-ME) e polarização fluorescente (TPF). A frequência de animais sororreagentes foi de 26/525 (4,95%) no teste AAT e 17/525 (3,23%) e 13/525 (2,47%) nos testes de 2-ME e TPF, respectivamente. A frequência de rebanhos foco, com pelo menos um animal soropositivo, foi de 9/35 (25,71%) e 8/3 (22,85%), nessa ordem. Referente aos ordenhadores, 1/60 (1,66%) foi reagente nos testes confirmatórios de 2-ME, TPF e fixação de complemento. O fator de risco associado à ocorrência da brucelose, na análise multivariada, foi presença de ovinos (odds ratio - OR=6,66; intervalo de confiança de 95% - IC95% 1,26-35,03). O estudo demonstrou que a brucelose está disseminada no rebanho leiteiro investigado, indicando a necessidade de melhorias nas ações de controle e erradicação da brucelose na região estudada.

Sources of spatial animal and human health data: Casting the net wide to deal more effectively with increasingly complex disease problems

During the last 30years it has become commonplace for epidemiological studies to collect locational attributes of disease data. Although this advancement was driven largely by the introduction of handheld global positioning systems (GPS), and more recently, smartphones and tablets with built-in GPS, the collection of georeferenced disease data has moved beyond the use of handheld GPS devices and there now exist numerous sources of crowdsourced georeferenced disease data such as that available from georeferencing of Google search queries or Twitter messages. In addition, cartography has moved beyond the realm of professionals to crowdsourced mapping projects that play a crucial role in disease control and surveillance of outbreaks such as the 2014 West Africa Ebola epidemic. This paper provides a comprehensive review of a range of innovative sources of spatial animal and human health data including data warehouses, mHealth, Google Earth, volunteered geographic information and mining of internet-based big data sources such as Google and Twitter. We discuss the advantages, limitations and applications of each, and highlight studies where they have been used effectively.

Brucellosis in low-income and middle-income countries

PURPOSE OF REVIEW

Human brucellosis is a neglected, underrecognized infection of widespread geographic distribution. It causes acute febrile illness and a potentially debilitating chronic infection in humans, and livestock infection has substantial socioeconomic impact. This review describes new information regarding the epidemiology of brucellosis in the developing world and advances in diagnosis and treatment.

RECENT FINDINGS

The highest recorded incidence of human brucellosis occurs in the Middle East and Central Asia. Fever etiology studies demonstrate brucellosis as a cause of undifferentiated febrile illness in the developing world. Brucellosis is a rare cause of fever among returning travelers, but is more common among travelers returning from the Middle East and North Africa. Sensitive and specific rapid diagnostic tests appropriate for resource-limited settings have been validated. Randomized controlled trials demonstrate that optimal treatment for human brucellosis consists of doxycycline and an aminoglycoside. Decreasing the burden of human brucellosis requires control of animal brucellosis, but evidence to inform the design of control programs in the developing world is needed.

SUMMARY

Brucellosis causes substantial morbidity in human and animal populations. While improvements in diagnostic options for resource-limited settings and stronger evidence for optimal therapy should enhance identification and treatment of human brucellosis, prevention of human disease through control in animals remains paramount.