Modelling control strategies against classical swine fever: Influence of traders and markets using static and temporal networks in Ecuador.

Pig farming in Ecuador represents an important economic and cultural sector, challenged by classical swine fever (CSF). Recently, the National Veterinary Service (NVS), has dedicated its efforts to control the disease by implementing pig identification, mandatory vaccination against CSF and movement control. Our objective was to characterise pig premises according to risk criteria, to model the effect of movement restriction strategies and to consider the temporal evolution of the network. Social network analysis (SNA), SIRS (susceptible, infected, recovered, susceptible) network modelling and temporal analysis were used. The network contained 751,003 shipments and 6 million pigs from 2017 to 2019. Participating premises consisted of 144,118 backyard farms, 138 industrial farms, 21,337 traders and 51 markets. The 10 most influential markets, in the Andean highlands, received between 500 and 4600 pigs each week. The 10 most influential traders made about 3 shipments with 17 pigs per week. Simulations without control strategy resulted in an average CSF prevalence of 14.4 %; targeted movement restriction reduced the prevalence to 7.2 %, while with random movement restriction it was 13 %. Targeting the top 10 national traders and markets and one of the high-risk premises in every parish was one of the best strategies with the surveillance infrastructure available, highlighting its major influence and epidemiological importance in the network. When comparing the static network with its temporal counterpart, causal fidelity (c = 0.62) showed a 38 % overestimation in the number of transmission paths, also traversing the network required 4.39 steps, lasting approximately 233 days. In conclusion, NVS surveillance strategies could be more efficient by targeting the most at-risk premises, and in particular, taking into account the temporal information would make the risk assessment much more precise. This information could contribute to implement risk-based surveillance reducing the time to eradicate CSF and other infectious animal diseases.

Corrigendum: Risk of Introduction of Bovine Tuberculosis (TB) Into TB-Free Herds in Southern Bahia, Brazil, Associated With Movement of Live Cattle.

[This corrects the article DOI: 10.3389/fvets.2018.00230.].

Economic appraisal of vaccination against Streptoccocus agalactiae in Nile tilapia farms in Brazil.

Infection with Streptococcus agalactiae causes mortality and major economic losses in Nile tilapia (Oreochromis niloticus) farming worldwide. In Brazil, serotype strains Ia, Ib and III have been isolated in streptococcosis outbreaks, but serotype Ib is the most prevalent. Vaccination is considered an effective method to prevent economically-important diseases in aquaculture and has been associated with decreased use of antibiotics and improvements in fish survival. We developed a flexible partial-budget model to undertake an economic appraisal of vaccination against Streptococcus agalactiae in Nile tilapia farmed in net cages in large reservoirs. The model considers the benefits and costs that are likely to be associated with vaccination at the farm-level, in one production cycle. We built three epidemiological scenarios of cumulative mortality attributable to S. agalactiae (5%, 10%, and 20%, per production cycle) in a non-vaccinated farm. For each scenario, we applied a stochastic model to simulate the net return of vaccination, given a combination of values of "vaccine efficacy", "gain in feed conversion ratio", "feed price", "fish market price ", and "cost of vaccine dose". In the 20% cumulative mortality scenario, the net return would break-even (benefits ≥ costs) in at least 97.9% of interactions. Should cumulative mortality be lower than 10%, the profitability of vaccination would be more dependent on better feed conversion ratio. The inputs "feed price" and "cost of vaccine" had minor effects on the output, in all pre-vaccination mortality scenarios. Although our simulations are based on conservative values and consider uncertainty about the modeled parameters, we conclude that vaccination against S. agalactiae is likely to be profitable in Nile tilapia farms, under similar production conditions.

Risk of Introduction of Bovine Tuberculosis (TB) Into TB-Free Herds in Southern Bahia, Brazil, Associated With Movement of Live Cattle.

Bovine tuberculosis (TB) is a zoonotic disease, endemic in Brazil, with an impact on public health and trade. TB causes direct and indirect financial losses to infected farms and regions. Our study aimed at quantifying the risk of introduction of TB into TB-free herds of southern Bahia, Brazil, via movement of live cattle from other regions of the State. Results suggest that the annual risk of introducing TB into free farms of southern Bahia, either through legal or illegal trade of live cattle, is very low, varying, on average, between 0.001 and 0.006 depending on the region of origin of the animals. Noteworthy, illegal movements accounted for 90% of the risk demonstrating the importance of compliance with official regulations. These results are useful to inform both veterinary authorities and farmers in making decisions related to the regionalization of the control for TB in the country, with the ultimate goal of eliminating this major zoonotic disease from an important dairy region of Brazil.

Situação epidemiológica da anemia infecciosa equina em equídeos de tração do Distrito Federal / Epidemiological status of equine infeccious anemia in working equidae from the Federal District, Brazil

A anemia infecciosa equina (AIE) é uma doença causada por um lentivirus que possui distribuição mundial. Essa enfermidade é um entrave ao desenvolvimento da equinocultura no Brasil devido à obrigatoriedade de eutanásia dos animais positivos. Este trabalho teve como objetivo estimar a prevalência de AIE em equídeos de tração no Distrito Federal, assim como identificar fatores de risco associados à doença. Foram sorteados aleatoriamente 350 proprietários (Unidades Primárias de Amostragem- UPA) e foram amostrados todos os equídeos (Unidades secundárias de Amostragem) de cada proprietário sorteado, totalizando 496 animais. As amostras sanguíneas foram analisadas no Lanagro/MG por meio da técnica de imunodifusão em ágar gel (IDGA). No momento da coleta de sangue, também foi aplicado um questionário epidemiológico para a análise de possíveis fatores de risco. A prevalência de AIE nas UPA foi estimada em 2,29%, (IC 95%: 1,01-4,2%) e nos animais foi de 1,81% (IC 95%: 0,55-3,07%). A prevalência foi significativamente maior em muares do que em equinos. Não foi possível comprovar a presença de nenhum outro fator de risco associado à doença. Este estudo demonstra que a prevalência da AIE em equídeos de tração é baixa no Distrito Federal, porém mais alta do que os dados de vigilância de rotina sugerem, o que justifica a eutanásia dos equídeos reagentes, com a finalidade de promover a erradicação da enfermidade. Ratifica-se a importância da realização de exames periódicos nesses animais e a manutenção das atividades de vigilância.(AU)

Equine Infectious Anaemia (EIA) is a disease that has worldwide distribution and it is caused by a lentivirus. The disease constrains the development of horse breeding in Brazil, leading to compulsory slaughter of test positive animals. The objective of this study was to estimate the prevalence of EIA in traction equids and identify potential risk factors in the Federal District. Three hundred and fifty (350) owners were randomly selected (Primary Sampling Units-PSU) and all equids (Secondary Sampling Units - SSU) from each owner were sampled, in a total of 496 animals. Blood samples were tested in LANAGRO/MG using the agar-gel immunodiffusion test (AGID). An epidemiological questionnaire was used to collect data on potential risk factors associated with the disease. The prevalence of PSU (owners) was estimated at 2.29% (95% CI: 1.01-4.2%) and the prevalence in animals was 1.81% (95% CI: 0.55-3.07%). Prevalence was higher in mules than in horses. None of the other variables analyzed as potential risk factors was associated to the presence of the disease. The present study demonstrated that the prevalence of EIA in traction equids is low in the Federal District, which strengthens the case for the maintaining the test-and-cull policy and the need for disease surveillance measures aimed at eradicating the disease.(AU)

Competencies for government veterinary services of the future: Summary of ISVEE 14 Yucatan 2015 roundtable discussion.

This short communication summarizes the strengths and weaknesses of current organisational structures in government veterinary services, as well as future technical, financial and societal challenges and related necessary competencies for government veterinary services of the future as discussed by an expert panel at ISVEE2015. First, participating representatives of veterinary services of diverse geographical backgrounds and statements from the audience confirmed that non-technical skills such as ability to work in teams, adaptability to new environments and situations, social and communication skills are increasingly seen as important. The second challenge faced by veterinary services is related to capacity issues, i.e. to have enough manpower to plan and deliver according to legislation in a period of shrinking budgets. New and emerging diseases can result in sudden, massive increases in the workload of veterinary services. Technical complexity has also increased for some hazards. Staff skills in veterinary services therefore need to be continuously updated, and it is essential to establish cross technical collaboration with other sectors including food safety, public health and environment. ISVEE conferences were seen as an opportunity to provide a global platform to develop skills needed by veterinary services, now and in the future.

Análise de detecção de cluster na caracterização espaço-temporal da tuberculose bovina no estado da Bahia / Cluster detection analyses for temporal-spatial characterization of bovine tuberculosis in Bahia, Brazil

A tuberculose bovina (BTB) é uma enfermidade causada pela infecção pelo Mycobacterium bovis que acomete o homem e diversas espécies de mamíferos. A BTB tem grande importância por causar prejuízos econômicos nas regiões infectadas e por seu impacto na saúde pública. Foi realizado inquérito epidemiológico no Estado da Bahia, entre 2008 e 2010, com o objetivo de estimar a prevalência e conhecer a distribuição espaço temporal da enfermidade. O Estado foi estratificado em quatro regiões, cada uma com características epidemiológicas e demográficas homogêneas representativas de formas de produção pecuária. Um total de 18.810 cabeças com idade superior a 2 anos foi amostrado em 1350 propriedades. O teste cervical comparativo foi aplicado em cada animal selecionado, sendo considerados positivos os animais reagentes positivos ou duas vezes inconclusivos. Latitude e Longitude foram tomadas para cada propriedade amostrada com o auxilio do aparelho de Global Positioning System (GPS). O teste de Cuzick-and-Edwards e a análise de rastreio espacial (spatial scan statistic) foram utilizados para identificar qualquer agrupamento espacial de BTB. A prevalência de rebanho na Bahia, indicando a proporção de propriedades foco, foi de 1,6% (IC 95%: 1,0% - 2,69% por região). Nenhuma evidência significativa (P<0.05) de aglomeração espacial ou clustering foi detectada, possivelmente devido à baixa prevalência da doença. Estes resultados sugerem que a BTB tem baixa prevalência no estado da Bahia e que, nestas condições epidemiológicas, os focos encontrados não podem ser explicados por fatores espacialmente estruturados.

Bovine tuberculosis (BTB) is a disease caused by the infection with Mycobacterium bovis that affects humans and several mammalian species. BTB is important, because it inflicts far-reaching economic losses to infected regions, and due to its impact on public health. Epidemiological surveys were conducted in the State of Bahia between 2008 and 2010 with the objective to estimate the prevalence and to assess the spatial distribution of the disease. The State of Bahia has been stratified into four regions, each of them representing a set of homogeneous epidemiological and demographic characteristics, referred to as Production Circuits. A total of 18,810 more than 2-year-old cattle in 1,305 herds, ranging from 320 to 370 ones per region, and 20 to 40 cattle per herd were randomly selected. A cervical comparative test was applied to each selected animal; reactive cattle and cattle with two consecutive inconclusive tests were considered BTB-positive, whereas non-reactive cattle were considered BTB-negative. Positive herds were classified as those with <20 sampled cattle and at least one BTB-positive, as well as those with 40 cattle sampled with <2 BTB-positive animals. Latitude and longitude were recorded for each sampled herd with a generic Global Positioning System (GPS). The Cuzick-and-Edwards' test and the spatial scan statistic were used to assess whether BTB was spatially clustered. Herd-level prevalence, as indicated by the proportion of case-herds, was 1.6% (range 0.3 to 2.9% per region). No significant evidence (P<0.05) of spatial clustering was detected, most likely due to the low disease prevalence in the region. Results here suggest that BTB is low prevalent in the State of Bahia and that under these conditions epidemiological outbreaks found cannot be explained by spatially-structured factors.

Prevalência e fatores de risco para a leptospirose em bovinos de Mato Grosso do Sul / Prevalence and risk factors for bovine leptospirosis in Mato Grosso do Sul, Brazil

Foi investigada a prevalência de anticorpos antileptospira em fêmeas bovinas com idade igual ou superior a 24 meses, provenientes de 178 rebanhos de 22 municípios do estado de Mato Grosso do Sul, bem como identificados fatores de risco associados à infecção. Foram analisadas 2.573 amostras de soro sangüíneo por meio do teste de soroaglutinação microscópica perante 10 sorovares de leptospira. Títulos iguais ou superiores a 100 para um ou mais sorovares foram detectados em 1.801 fêmeas (98,8 por cento) de 161 (96,5 por cento) rebanhos. O sorovar Hardjo (65,6 por cento) foi apontado como o mais provável, seguido do sorovar Wolffi (12,3 por cento). Os resultados demonstram que a leptospirose bovina se encontra presente em todos os municípios estudados, com alta prevalência, tanto em animais como em rebanhos. Os fatores de risco identificados neste estudo e associados à infecção por bactérias do gênero lepstopira foram o tipo de exploração pecuária de corte e a raça Zebu.

The prevalence of anti-Leptospira spp. antibodies was estimated for female cattle aged 24 months or older. The sample comprised 178 herds from 22 counties in the state of Mato Grosso do Sul, Brazil. The risk factors associated with the presence of infeccion were investigated. A total of 2,573 blood serum samples were tested against 10 leptospira serovars using the microagglutination test (MAT). Titers of 100 or higher for one or more serovars were detected in 1,801 females (98.8 percent) from 161 herds (96.5 percent). Serovar Hardjo (65.6 percent) was the most frequent, followed by serovar Wolffi (12.3 percent). These results suggest that bovine leptospirosis is widespread in all the counties under study, with a high prevalence both at the animal and the herd level. Beef farms and the Zebu breed were associated to the higher risk of herd infection by leptospiras.

Efficacy of strain RB51 vaccine in heifers against experimental brucellosis.

With the goal of providing an additional tool for controlling bovine brucellosis in Brazil and evaluating the full calf dose in adult cattle, the efficacy of the rough Brucella abortus strain RB51 vaccine was tested in heifers. Thirty-three females of approximately 24 months of age were divided in two groups: one group (n=20) received the RB51 vaccine and the other group (n=13) were used as non-vaccinated control. Animals in the vaccinated group were split in two sub-groups. One sub-group (n=12) was vaccinated subcutaneously with 1.5x10(10) colony forming units (CFU) of RB51 at Day 0 of the experiment and the other sub-group (n=8) was vaccinated subcutaneously with 1.6x10(10) CFU of RB51 at 60 days of gestation (Day 260 of the experiment). All cattle were challenged between 6 and 7 months of pregnancy with 3x10(8) CFU of the virulent strain 2308 of B. abortus by the conjunctival route. Vaccination with RB51 vaccine did not result in the production of any antibodies against the O-side chain of lipopolysaccharide (LPS), as measured by conventional serological tests (rose bengal plate agglutination test (RBPAT), standard tube agglutination test (STAT), and 2-mercaptoethanol test (2ME)). A total of 25% cumulative incidence of abortions was found in the vaccinated group, whereas in the control group the cumulative incidence was 62%. B. abortus RB51 was not isolated from any sample, and no abortions were produced by RB51 vaccination of females at 60 days of pregnancy. The results indicate that vaccination with RB51 prevented 59.4% of abortions, 58.6% of cow infections, and 61.0% of fetal infections. The relative risk (RR) revealed that non-vaccinated animals have 2.462 (95% CI 1.029-5.889) times higher risk of aborting than RB51-vaccinated animals.