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1.
Foodborne Pathog Dis ; 2020 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-32191498

RESUMO

The objective of this study was to quantify the frequency, distribution, and variability of fecal shedding and super-shedding of Shiga toxin-producing Escherichia coli (STEC) serogroups O26, O45, O103, O111, O121, O145, and O157 in feedlot cattle over time. A total of 750 fecal grab samples were collected over a 5-week period (June-July 2017) from 150 cattle housed in 10 pens at a commercial feedlot operation. Samples were subjected to culture-based methods and real-time quantitative polymerase chain reaction for STEC detection and quantification. Cumulative animal-level prevalence estimates were 9.5%, 5.2%, and 15.8% for STEC O157, non-O157 STEC serogroups only (STEC-6), and for all STEC serogroups tested (STEC-7), respectively, with the prevalence of STEC O157 and STEC-7 significantly differing between weeks (p < 0.01). Most of the variability in fecal shedding for STEC O157, STEC-6, and STEC-7 was between pens, rather than between cattle. Over the 5-week period, 10 animals (6.7%) persistently shed STEC non-O157 over 3 or more consecutive weeks, whereas 2 animals (1.3%) intermittently shed STEC non-O157 on nonconsecutive weeks. Fifteen animals (10.0%) shed multiple STEC serogroups within the same fecal sample and five animals (3.3%) shed multiple serogroups at super-shedding levels, higher than 104 CFU (colony-forming units)/g, in the same sample. The presence of a super-shedder in a pen was significantly associated with a greater within pen-level prevalence of STEC-6 (p = 0.01). This study gives further insights into intermittent and persistent shedding and super-shedding patterns of STEC serogroups in individual feedlot cattle, which can enable the development and effective application of preharvest and periharvest interventions, as well as surveillance strategies, for these pathogens.

2.
BMC Vet Res ; 15(1): 394, 2019 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-31690309

RESUMO

BACKGROUND: Osteoarthritis (OA) affects nearly 20% of all dogs greater than one year of age. Clinical signs include pain, discomfort, lameness, and ultimately lead to disability. Although there is currently no known cure, there are many therapeutic options that can slow the progression and alleviate the associated signs. There is ample supportive evidence demonstrating the efficaciousness of carprofen, a non-steroidal anti-inflammatory drug, in managing signs of OA. Since the approval of the pioneer product (Rimadyl®, Zoetis; Kalamazoo, Michigan), the United States Food and Drug Administration (FDA) has assented to several other generic, bioequivalent products. The objective of this 2 × 2 complete cross-over design was to assess the acceptance of two bioequivalent carprofen liver-flavored chewable tablets (containing 25 mg carprofen), Rimadyl® and Carprieve® (Norbrook Laboratories Limited; Newry, Northern Ireland) in 37 healthy purpose-bred dogs. RESULTS: Overall, 73.0% (27/37) and 70.3% (26/37) of dogs voluntarily accepted Rimadyl® and Carprieve®, respectively. Considering acceptability tests paired by individual dog, 64.9% of dogs (n = 24) voluntarily accepted both Rimadyl® and Carprieve® chewable tablets whereas 21.6% (8) of dogs denied or partially accepted both products offered. Three dogs (8.1%) fully accepted Rimadyl® but did not accept Carprieve®. Conversely, two dogs (5.4%) fully accepted Carprieve® but did not accept Rimadyl®. Canine acceptability did not significantly differ between Carprieve® and Rimadyl® carprofen chewable tablets (P = 0.65). CONCLUSIONS: Utilizing a 2 × 2 complete cross-over design, this study provides evidence that canine acceptability of a single-dose did not differ between Carprieve® and Rimadyl® chewable tablets.

3.
Can J Vet Res ; 83(4): 313-316, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31571732

RESUMO

The objective of this study was to evaluate the effect of late-gestation vaccination of beef heifers with 2 doses of a killed-virus (KV) vaccine containing bovine herpesvirus 1 (BoHV-1), bovine viral diarrhea virus 1 (BVDV-1), and bovine viral diarrhea virus 2 (BVDV-2) on the serum concentrations of antibody against BoHV-1, BVDV-1, and BVDV-2 in heifers and their calves and on the IgG concentration in the calves. Of the 47 pregnant beef heifers selected, 26 received 2 doses of the vaccine at 6.5 to 8 mo of gestation (at pregnancy check), and 21 received 2 doses of saline. The mean log2 serum titers of neutralizing antibody against BoHV-1, BVDV-1, and BVDV-2 before vaccination did not differ significantly between the treatment groups; however, at calving all 3 mean titers were significantly greater (P < 0.05) in the vaccinated heifers than in the control heifers. At 24 h after birth the mean serum IgG levels in the calves did not differ significantly between the 2 groups, at 30.18 and 32.28 g/L, respectively (P < 0.05); however, the mean log2 serum titers of antibody to all 3 viruses were greater in the calves nursing colostrum from the vaccinated heifers than in the calves nursing colostrum from the nonvaccinated heifers and significantly so for BoHV-1 and BVDV-1 (P < 0.001 and P = 0.009, respectively). Thus, late-gestation vaccination of beef heifers could result in a greater and more consistent deposition of specific antibodies in colostrum, reducing the variability of initial titers in calves and increasing the duration of maternal immunity.


Assuntos
Anticorpos Antivirais/sangue , Doenças dos Bovinos/prevenção & controle , Vírus da Diarreia Viral Bovina/imunologia , Herpesvirus Bovino 1/imunologia , Imunoglobulina G/sangue , Vacinas Virais/imunologia , Animais , Especificidade de Anticorpos , Bovinos , Doenças dos Bovinos/sangue , Doenças dos Bovinos/imunologia , Feminino , Imunidade Materno-Adquirida , Gravidez , Vacinação/veterinária
4.
PLoS One ; 14(10): e0223378, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31584976

RESUMO

Antimicrobial drug concentrations in the gastrointestinal tract likely drive antimicrobial resistance in enteric bacteria. Our objective was to determine the concentration of ceftiofur and its metabolites in the gastrointestinal tract of steers treated with ceftiofur crystalline-free acid (CCFA) or ceftiofur hydrochloride (CHCL), determine the effect of these drugs on the minimum inhibitory concentration (MIC) of fecal Escherichia coli, and evaluate shifts in the microbiome. Steers were administered either a single dose (6.6 mg/kg) of CCFA or 2.2 mg/kg of CHCL every 24 hours for 3 days. Ceftiofur and its metabolites were measured in the plasma, interstitium, ileum and colon. The concentration and MIC of fecal E. coli and the fecal microbiota composition were assessed after treatment. The maximum concentration of ceftiofur was higher in all sampled locations of steers treated with CHCL. Measurable drug persisted longer in the intestine of CCFA-treated steers. There was a significant decrease in E. coli concentration (P = 0.002) within 24 hours that persisted for 2 weeks after CCFA treatment. In CHCL-treated steers, the mean MIC of ceftiofur in E. coli peaked at 48 hours (mean MIC = 20.45 ug/ml, 95% CI = 10.29-40.63 ug/ml), and in CCFA-treated steers, mean MIC peaked at 96 hours (mean MIC = 10.68 ug/ml, 95% CI = 5.47-20.85 ug/ml). Shifts in the microbiome of steers in both groups were due to reductions in Firmicutes and increases in Bacteroidetes. CCFA leads to prolonged, low intestinal drug concentrations, and is associated with decreased E. coli concentration, an increased MIC of ceftiofur in E. coli at specific time points, and shifts in the fecal microbiota. CHCL led to higher intestinal drug concentrations over a shorter duration. Effects on E. coli concentration and the microbiome were smaller in this group, but the increase in the MIC of ceftiofur in fecal E. coli was similar.

5.
One Health ; 8: 100103, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31528684

RESUMO

Livestock losses due to rabies and health and the corresponding benefits of controlling the disease are not often considered when the cost-effectiveness of rabies control is evaluated. In this research, assessed the benefits of applying a One Health perspective that includes these losses to the case of canine rabies vaccination in Ethiopia. We constructed a dynamic epidemiological model of rabies transmission. The model was fit to district-specific data on human rabies exposures and canine demography for two districts with distinct agro-ecologies. The epidemiological model was coupled with human and livestock economic outcomes to predict the health and economic impacts under a range of vaccination scenarios. The model indicates that human exposures, human deaths, and rabies-related livestock losses would decrease monotonically with increasing vaccination coverage. In the rural district, all vaccination scenarios were found to be cost-saving compared to the status quo of no vaccination, as more money could be saved by preventing livestock losses than would be required to fund the vaccination campaigns. Vaccination coverages of 70% and 80% were identified as most likely to provide the greatest net health benefits at the WHO cost-effectiveness threshold over a period of 5 years, in urban and rural districts respectively. Shorter time frames led to recommendations for higher coverage in both districts, as did even a minor threat of rabies re-introduction. Exclusion of rabies-related livestock losses reduced the optimal vaccination coverage for the rural district to 50%. This study demonstrated the importance of including all economic consequences of zoonotic disease into control decisions. Analyses that include cattle and other rabies-susceptible livestock are likely better suited to many rural communities in Africa wishing to maximize the benefits of canine vaccination.

6.
Foodborne Pathog Dis ; 16(12): 844-855, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31381377

RESUMO

Fecal bacteria, which reside in the gastrointestinal tract of cattle, can contaminate beef carcasses during processing. In beef cattle slaughter plants, the presence and concentrations of generic Escherichia coli, coliforms, Enterobacteriaceae (EB), and total aerobic bacteria are monitored as indicator organisms of fecal and environmental contamination. The objectives of this study were as follows: (1) to determine the concentrations of generic E. coli, coliforms, EB, and aerobic bacteria on beef carcasses at different processing points in Midwestern commercial beef slaughter plants during the summer, spring, and fall seasons; and (2) to estimate bacterial transfer on carcasses during the hide removal and evisceration processes. Hide and carcass surface sample swabs were collected from slaughtered cattle at four large commercial processing plants. At each plant visit (3 visits to each of the 4 plants) and during 3 seasons, 20 samples were collected at 5 points: hide-on (hide of animal near exsanguination pit), hide-off carcass, pre-evisceration carcass, postevisceration carcass, and postintervention carcass, for a total of 3600 samples. Bacterial concentrations were determined using 3M™ Petrifilm™ plates. Associations between season and processing plant with concentrations of E. coli, coliforms, EB, and total aerobic bacteria, overall, between hide-on and hide-off, and between pre- and post-evisceration, were evaluated using multilevel mixed-effects linear regression models. Bacterial concentrations on beef carcasses significantly decreased throughout processing. Moreover, hide removal was an important source of carcass contamination, given bacterial concentrations detected on hide-off carcass samples were the highest, and bearing in mind that carcass muscle surfaces should be sterile. Results from this study indicate that the interventions applied by the processing plants were effective, as they probably contributed to the significant reduction of bacterial concentrations of carcasses.

7.
J Anim Sci ; 97(6): 2357-2367, 2019 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-30923802

RESUMO

The objective of this study was to evaluate the diagnostic performance of chute-side diagnostic methods for detecting physiological and pathological changes as indicators of early bovine respiratory disease (BRD) in calves experimentally inoculated with infectious bovine rhinotracheitis virus (IBR) and Mannheimia haemolytica (Mh). A challenge study was performed over 14 d in 30 Holstein steers [average weight (±SEM) = 211 kilograms (kg) ± 2.4 kg] inoculated on day 0 with IBR and on day 6 with Mh. Diagnostic methods included clinical illness scores (CIS), lung auscultation using a computer-aided stethoscope (CAS), rectal temperature, facial thermography, pulse oximetry, and bilateral thoracic ultrasonography. Animals were randomized into 1 of 5 necropsy days (days 6, 7, 9, 11, and 13) when the percentage of lung consolidation was estimated. The effect of study day on the results of the diagnostic methods and associations between each diagnostic method's values with lung consolidation measured at necropsy were determined with mixed models. Values for all diagnostic methods differed significantly (P < 0.01) by day. During the IBR phase (days 0 to 6) calves had "normal" to "moderate" CIS, whereas during the Mh phase (days 6.5 to 13) scores were predominantly "severe" to "moribund." Similarly, CAS scores were "normal" and "mild acute" during the IBR phase and "mild acute" to "moderate acute" after the Mh challenge. Oxygen saturation did not differ significantly between days 0, 1, 2, 4, and 6; however, significantly decreased 12 h after inoculation with Mh (P < 0.05). Mean lung consolidation between animal's right and left side recorded by ultrasound was 0.13% (±0.07) before the inoculation with Mh. However, during the Mh phase, mean consolidation increased significantly over time (P < 0.05). The percentage of lung consolidation at necropsy ranged from 1.7% (±0.82) on day 6 to 55.4% (±7.49) on day 10. Clinical illness scores, rectal temperature, facial thermography, oxygen saturation, and ultrasonography were significantly associated (P < 0.05) with lung consolidation at necropsy. In addition, there was a significant trend (P = 0.07) between CAS and lung consolidation scores at necropsy. These chute-side diagnostic methods are useful for detecting disease progression on animals with early stages of BRD.


Assuntos
Doenças dos Bovinos/diagnóstico , Herpesvirus Bovino 1/fisiologia , Mannheimia haemolytica/fisiologia , Doenças Respiratórias/veterinária , Animais , Bovinos , Doenças dos Bovinos/patologia , Progressão da Doença , Diagnóstico Precoce , Pulmão/patologia , Masculino , Doenças Respiratórias/diagnóstico , Doenças Respiratórias/patologia
8.
Transbound Emerg Dis ; 66(4): 1558-1574, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30900804

RESUMO

The purpose of this risk assessment (RA) was to qualitatively estimate the risk of emergence of the Japanese encephalitis virus (JEV) in the United States (US). We followed the framework for RA of emerging vector-borne livestock diseases (de Vos et al. 2011), which consists of a structured questionnaire, whose answers to questions can be delivered in risk categories, descriptive statements, or yes or no type of answers, being supported by the literature. The most likely pathways of introduction of JEV identified were: (a) entry through infected vectors (by aircraft, cargo ships, tires, or wind); (b) import of infected viremic animals; (c) entry of viremic migratory birds; (d) import of infected biological materials; (e) import of infected animal products; (f) entry of infected humans; and (g) import/production of contaminated biological material (e.g., vaccines). From these pathways, the probability of introduction of JEV through infected adult mosquitoes via aircraft was considered very high and via ships/containers was deemed low to moderate. The probability of introduction via other pathways or modes of entry (vector eggs or larvae, hosts, and vaccines) was considered negligible. The probability of transmission of JEV was variable, ranging from low to high (in the presence of both competent vectors and hosts), depending on the area of introduction within the US. Lastly, the probability of establishment of JEV in the continental US was considered negligible. For that reason, we stopped the risk assessment at this point of the framework. This RA provides important information regarding the elements that contribute to the risk associated with the introduction of JEV in the US. This RA also indicates that infected mosquitoes transported in aircraft (and cargo ships) are the most likely pathway of JEV entry and therefore, mitigation strategies should be directed towards this pathway.


Assuntos
Culicidae/virologia , Vírus da Encefalite Japonesa (Espécie)/isolamento & purificação , Encefalite Japonesa/epidemiologia , Mosquitos Vetores/virologia , Animais , Aves , Culex/virologia , Encefalite Japonesa/transmissão , Encefalite Japonesa/virologia , Humanos , Gado , Probabilidade , Medição de Risco , Inquéritos e Questionários , Estados Unidos/epidemiologia
9.
Foodborne Pathog Dis ; 16(4): 276-281, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30615484

RESUMO

This study evaluated the seasonal prevalence and distribution of Salmonella spp., Salmonella enterica serovar Typhimurium (ST) and its monophasic variant 4,[5],12:i:- (STM), in selected swine feed mills across the United States. Eleven facilities were selected for this study and 12 sites were sampled within each mill during fall 2016, early spring 2017, and summer 2017. Samples were evaluated following the USDA-FSIS guidelines for Salmonella isolation and culture positive samples were analyzed by polymerase chain reaction (PCR). A multiplex real-time PCR was used to differentiate ST and STM from other serotypes. Associations between season, mill, and sample site with Salmonella presence were investigated using generalized linear mixed models. Both season (p < 0.007) and mill (p < 0.005) were significantly associated with Salmonella spp. presence. Fall months were associated with a higher Salmonella prevalence (13.2%) compared with early spring and summer. A total of five isolates, among the 383 samples were serotyped as ST and STM. These two serotypes showed a similar seasonal presence throughout the study, being found during fall and summer seasons. These findings demonstrated the seasonal presence of Salmonella spp. in feed mills and the role of these environments as potential pathogen entry route into the human food chain.

10.
Microbiologyopen ; 8(5): e00711, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30156384

RESUMO

Salmonella is a pathogen of public health concern. Each year, Salmonella infections cost to the food industry approximately $2.3 billion and 33% of the reported cases are associated with beef, poultry, or pork. Pathogen presence in feed mills can represent one of the many potential routes for entry and transmission into the food production chain. Nevertheless, little is known about Salmonella incidence and association with these types of environments. The objective of this study was to investigate Salmonella presence in different feed mills across the United States. Eleven facilities were selected in eight states and 12 sites were sampled within each feed mill. Samples were analyzed following the FSIS guidelines for isolation and identification of Salmonella. Positive isolates were further investigated by a PCR analysis targeting the invA gene to differentiate for Salmonella enterica. The total number of environmental samples collected was 237: 66% resulted culture positive and 13.1% were PCR positive. All sampled feed mills had at least one culture positive site and following production flow the number of positive samples decreased from ingredient receiving to final product. These preliminary results demonstrate the presence of Salmonella in selected United States feed mills and suggest their potential role as vehicle for pathogen transmission and spread into the food production chain.

11.
Prev Vet Med ; 161: 90-99, 2018 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-30466664

RESUMO

Non-O157 Shiga toxin-producing Escherichia coli (non-O157 STEC, O26, O45, O103, O111, O121, and O145) are foodborne pathogens of public health importance. Culture and PCR-based methods have been developed for the detection of these serogroups in cattle feces. The objectives of this study were to evaluate diagnostic sensitivity and specificity of PCR- and culture-based methods for the detection of the six non-O157 serogroups, and to estimate their true prevalence in cattle feces, using a Bayesian latent class modeling approach that accounts for conditional dependence among the three methods. A total of 576 fecal samples collected from the floor of pens of finishing feedlot cattle during summer 2013 were used. Fecal samples, suspended in E. coli broth, were enriched and subjected to three detection methods: culture (involving immunomagnetic separation with serogroup specific beads and plating on a selective medium), conventional (cPCR), and multiplex quantitative PCR (mqPCR) assays. Samples were considered serogroup positive if the sample or the recovered isolate tested positive by PCR for an O gene of interest; neither Shiga toxin (stx) nor intimin (eae) genes were assessed. Prior information on the performance of the three methods was elicited from three subject experts. Culture was generally the least sensitive and most specific of the 3 tests across serogroups, mqPCR was generally the most sensitive test and cPCR more specific than mqPCR. Sensitivity analysis indicated that posterior inferences on test performance and prevalence were susceptible to prior specification in cases where few or no detections present in the data for selected combinations of diagnostic methods (i.e. extreme category problem). Our results characterize performance of detection methods and true prevalence of non-O157 serogroups, thus informing necessary adjustments for test bias in risk modeling.


Assuntos
Técnicas Bacteriológicas/veterinária , Doenças dos Bovinos/epidemiologia , Doenças dos Bovinos/microbiologia , Infecções por Escherichia coli/veterinária , Escherichia coli/isolamento & purificação , Reação em Cadeia da Polimerase Multiplex/veterinária , Animais , Técnicas Bacteriológicas/normas , Teorema de Bayes , Bovinos , Doenças dos Bovinos/diagnóstico , Infecções por Escherichia coli/diagnóstico , Infecções por Escherichia coli/epidemiologia , Fezes/microbiologia , Microbiologia de Alimentos , Reação em Cadeia da Polimerase Multiplex/normas , Prevalência , Sensibilidade e Especificidade , Sorogrupo , Estados Unidos/epidemiologia
12.
Prev Vet Med ; 160: 1-9, 2018 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-30388990

RESUMO

Following a qualitative risk assessment, in which we identified and assessed all viable pathways for the introduction of the Japanese encephalitis virus (JEV) into the United States (US), we identified entry through infected vectors via aircraft and cargo ships as the most likely pathway, and thus considered it further in a quantitative risk assessment (QRA) model. The objective of this study was to evaluate the risk of introduction of JEV in the US via infected mosquitoes transported in aircraft and cargo ships arriving from Asia, using a QRA model. We created a stochastic model to quantify the probability of introduction of at least one infected mosquito in the continental US via aircraft and cargo ships, per at-risk period (March to October) or year, respectively. We modeled the following parameters: number of flights (per at-risk period, i.e., March to October) and cargo ships (per year) and per region, number of mosquitoes per flight and ship, number of mosquitoes that were not found and sensitivity of the mosquito collection method in aircraft, mosquito infection rates, and number of mosquitoes coming in aircraft per at-risk period (March to October) and cargo ships per year. Flight and cargo ship data pertained to years 2010-2016. For model building purposes, we only considered port-to-port vessels arriving from Asia to the US, we assumed that mosquitoes survive the trans-Pacific Ocean ship crossing and that the number of mosquitoes in cargo and passenger flights is similar. Our model predicted a very high risk (0.95 median probability; 95% CI = 0.80-0.99) of at least one infected mosquito being introduced in the US during the at-risk period, i.e., March to October, via aircraft transportation from JEV-affected countries in Asia. We also estimated that a median of three infected mosquitoes can enter the US during the at-risk period, i.e., March to October (95% CI = 1-7). The highest probability of introduction via aircraft was attributed to the Mediterranean California ecoregion (0.74; 95% CI = 0.50-0.90). We predicted, however, a negligible risk (0; 95% CI = 0.00-0.01) of at least one infected mosquito being introduced via cargo ships. Although the risk of introduction of JEV-infected mosquitoes by cargo ships was negligible, the risk via aircraft was estimated to be high. Our findings indicate the need to prioritize JEV prevention and control methods for aircraft-based pathways, such as aircraft disinfection. The quantitative estimates provided in this study are of interest to public health entities and other stakeholders, as they may support future interventions for preventing JEV introduction, as well as other vector-borne diseases, in the US and other countries.


Assuntos
Aeronaves , Culicidae/virologia , Vírus da Encefalite Japonesa (Espécie) , Encefalite Japonesa/transmissão , Navios , Animais , California/epidemiologia , Encefalite Japonesa/epidemiologia , Medição de Risco , Processos Estocásticos , Estados Unidos/epidemiologia
13.
J Virol Methods ; 262: 6-11, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30205125

RESUMO

Rift Valley fever virus (RVFV), a mosquito-borne, zoonotic pathogen, is endemic to sub-Saharan Africa and has spread beyond the continent to the Arabian Peninsula. The high likelihood of RVFV's spread to other non-endemic countries spurs the need for development and implementation of rapid diagnostic tests and surveillance programs. In this preliminary evaluation, we assessed the diagnostic accuracy and precision of a recombinant RVFV nucleoprotein based competitive ELISA (cELISA) assay to detect RVFV antibodies compared to a plaque reduction neutralization test (PRNT80), using sera of cattle and sheep that were experimentally infected with either the MP-12 RVFV vaccine or a wild-type RVFV strain, as well as using known RVFV negative sera. With the manufacturer recommended 60% inhibition for the cELISA and a 1:40 titer for the PRNT80, the sensitivity and specificity of the cELISA assay was determined to be 95.1% (95% CI = 83.5-99.4%) and 91.8% (95% CI = 85.0-96.2%), respectively. Antibodies to RVFV were first detected at 5 days post inoculation (dpi) in both species' sera. The prototype cELISA is an easy to implement, sensitive, specific, and safe test for the detection of antibodies to RVFV that can be used in surveillance programs.


Assuntos
Anticorpos Neutralizantes/sangue , Anticorpos Antivirais/sangue , Ensaio de Imunoadsorção Enzimática/métodos , Febre do Vale de Rift/diagnóstico , Animais , Bovinos , Doenças dos Bovinos/diagnóstico , Doenças dos Bovinos/virologia , Imunoglobulina G/sangue , Testes de Neutralização , Reprodutibilidade dos Testes , Febre do Vale de Rift/imunologia , Vírus da Febre do Vale do Rift/imunologia , Sensibilidade e Especificidade , Ovinos , Doenças dos Ovinos/diagnóstico , Doenças dos Ovinos/virologia
14.
Front Vet Sci ; 5: 159, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30050912

RESUMO

Ethiopia has one of the highest incidence levels of human rabies in Africa, with 3-7 deaths per 100,000 people annually. The country has no official rabies control programme, despite the availability of an effective canine vaccine to control rabies. To support effective rabies control, an understanding of the factors affecting dog owners' voluntary intentions to vaccinate their dogs is important. As such, this study examined factors influencing dog owners' intentions to vaccinate their dogs using the constructs of health belief theory. In this cross-sectional study, a questionnaire, designed based on the Health Belief Model constructs was completed by 249 dog owners in 9 randomly selected wards of Bishoftu town in central Ethiopia between October and December 2016. An ordinal regression model was then fitted to explore factors which best predict the likelihood of a dog owner's intention. A classification and regression tree (CART) model was then used for recursive partitioning of the Likert scale in the significant variables to distinctively classify ordinal categories of vaccination intention. Participants' preventive intention was associated with the six constructs of the Health Belief Model: perceived susceptibility, readiness to action, self-efficacy, perceived threat, benefits, and barriers. Dog owner's knowledge about rabies was found to be positively associated with intention to vaccinate, whereas distance from vaccination centers and difficulty of dog transportation were found to be negatively associated to intention to vaccinate. Distance from vaccination center was found to be the best predictor for the intention to vaccinate. The results of this study have policy implications for controlling rabies including increasing dog owners' knowledge about rabies, locating vaccination centers at shorter distances from dog populations and providing suitable means to transport dogs to vaccination centers.

15.
Data Brief ; 18: 1819-1824, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29904683

RESUMO

A real-time PCR (qPCR) assay targeting on invA and pagC genes was developed and validated for the detection and quantification of Salmonella enterica strains (Bai et al., 2018) [1]. A host gene, normally an endogenous housekeeping gene (Beer-Davidson et al., 2018; Poon et al., 2004) [2,3], or an irrelevant exogenous gene (Cheng et al., 2015; Sedlak et al., 2014) [4,5] has been widely used as an internal control to monitor nucleic acid extraction efficiencies and potential PCR inhibitions in PCR-based detection assays. An endogenous internal control designed based on the 18S rRNA gene was used in the above-mentioned qPCR assay. This 18S rRNA internal control amplifies the target gene in multiple species including bovine, swine, ovine, caprine and cervine. Data was generated by the duplex qPCR assay on 138 enriched cattle lymph node samples without the internal control, and compared with data on the same samples tested by the triplex qPCR assay that has the 18S rRNA gene as internal control. Threshold cycle (Ct) data for the duplex and the triplex qPCR on the 138 samples were similar, and are presented in this brief report.

16.
Prev Vet Med ; 154: 71-89, 2018 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-29685447

RESUMO

Japanese encephalitis virus (JEV) is a virus of the Flavivirus genus that may result in encephalitis in human hosts. This vector-borne zoonosis occurs in Eastern and Southeastern Asia and an intentional or inadvertent introduction into the United States (US) would have major public health and economic consequences. The objective of this study was to gather, appraise, and synthesize primary research literature to identify and quantify vector and host competence for JEV, using a systematic review (SR) of the literature. After defining the research question, we performed a search in selected electronic databases and journals. The title and abstract of the identified articles were screened for relevance using a set of exclusion and inclusion criteria, and relevant articles were subjected to a risk of bias assessment, followed by data extraction. Data were extracted from 171 peer-reviewed articles. Most studies were observational studies (59.1%) and reported vector competence (60.2%). The outcome measures reported pertained to transmission efficiency, host preference, and vector susceptibility to infection within vector competence; and susceptibility to infection within host competence. Regarding vector competence, the proportion of JEV infection reported across all 149 mosquito species in all observational studies ranged from 0 to 100%. In experimental studies, infection, dissemination, and transmission rates varied between 0 and 100%. Minimum infection rates (MIR) varied between 0 and 333.3 per 1000 mosquitoes. Maximum likelihood estimation (MLE) values ranged from 0 to 53.8 per 1000 mosquitoes. The host species in which mosquitoes mostly fed consisted of pigs and cattle (total of 84 blood meals taken by mosquitoes from each of these host species). As for host competence, the proportion of JEV infection varied between 0 (in rabbits, reptiles, and amphibians) and 88.9% (cattle). This SR presents comprehensive data on JEV vector and host competence, which can be used to quantify risks associated with the introduction of JEV into the US.


Assuntos
Vírus da Encefalite Japonesa (Espécie)/isolamento & purificação , Encefalite Japonesa/veterinária , Mosquitos Vetores/virologia , Animais , Bovinos , Culex/virologia , Vetores de Doenças , Encefalite Japonesa/epidemiologia , Encefalite Japonesa/transmissão , Humanos , Coelhos , Zoonoses
17.
Foodborne Pathog Dis ; 15(6): 377-385, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29638171

RESUMO

Campylobacter spp. can be pathogenic to humans and often harbor antimicrobial resistance genes. Data on resistance in relation to fluoroquinolone use in beef cattle are scarce. This cross-sectional study of preharvest cattle evaluated Campylobacter prevalence and susceptibility to nalidixic acid and ciprofloxacin in feedlots that previously administered a fluoroquinolone as primary treatment for bovine respiratory disease. Twenty fresh fecal samples were collected from each of 10 pens, in each of five feedlots, 1-2 weeks before harvest. Feces were cultured for Campylobacter using selective enrichment and isolation methods. Genus and species were confirmed via PCR. Minimum inhibitory concentrations (MICs) of ciprofloxacin and nalidixic acid were determined using a micro-broth dilution method and human breakpoints. Antimicrobial use within each pen was recorded. Data were analyzed using generalized linear mixed-models (prevalence) and survival analysis (MICs). Overall, sample-level prevalence of Campylobacter was 27.2% (272/1000) and differed significantly among feedlots (p < 0.01). Campylobacter coli was the most common species (55.1%; 150/272), followed by Campylobacter hyointestinalis (42.6%; 116/272). Within-pen prevalence was not significantly associated with the number of fluoroquinolone treatments, sex, body weight, or metaphylaxis use, but was associated with the number of days cattle were in the feedlot (p = 0.03). The MICs for the majority of Campylobacter isolates were above the breakpoints for nalidixic acid (68.4%; 175/256) and for ciprofloxacin (65.6%; 168/256). Distributions of MICs for nalidixic acid (p ≤ 0.01) and ciprofloxacin (p ≤ 0.05) were significantly different among feedlots, and by Campylobacter species. However, fluoroquinolone treatments, sex, body weight, days on feed, and metaphylaxis were not significantly associated with MIC distributions within pens. We found no evidence that the number of fluoroquinolone treatments within feedlot pens significantly affected the within-pen fecal prevalence or quinolone susceptibilies of Campylobacter in feedlots that used a fluoroquinolone as primary treatment for bovine respiratory disease.


Assuntos
Antibacterianos/uso terapêutico , Infecções por Campylobacter/veterinária , Campylobacter/efeitos dos fármacos , Doenças dos Bovinos/epidemiologia , Enrofloxacina/uso terapêutico , Quinolonas/farmacologia , Animais , Antibacterianos/farmacologia , Campylobacter/isolamento & purificação , Infecções por Campylobacter/tratamento farmacológico , Infecções por Campylobacter/epidemiologia , Infecções por Campylobacter/microbiologia , Bovinos , Doenças dos Bovinos/tratamento farmacológico , Doenças dos Bovinos/microbiologia , Estudos Transversais , Farmacorresistência Bacteriana , Kansas/epidemiologia , Prevalência , Texas/epidemiologia
18.
J Microbiol Methods ; 148: 110-116, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29621581

RESUMO

Cattle lymph nodes can harbor Salmonella and potentially contaminate beef products. We have developed and validated a new real-time PCR (qPCR) assay for the detection and quantification of Salmonella enterica in cattle lymph nodes. The assay targets both the invA and pagC genes, the most conserved molecular targets in Salmonella enterica. An 18S rRNA gene assay that amplifies from cattle and other animal species was also included as an internal control. Available DNA sequences for invA, pagC and 18S rRNA genes were used for primer and probe selections. Three Salmonella serotypes, S. Typhimurium, S. Anatum, and S. Montevideo, were used to assess the assay's analytical sensitivity. Correlation coefficients of standard curves generated for each target and for all three serotypes were >99% and qPCR amplification efficiencies were between 93% and 110%. Assay sensitivity was also determined using standard curve data generated from Salmonella-negative cattle lymph nodes spiked with 10-fold dilutions of the three Salmonella serotypes. Assay specificity was determined using Salmonella culture method, and qPCR testing on 36 Salmonella strains representing 33 serotypes, 38 Salmonella strains of unknown serotypes, 252 E. coli strains representing 40 serogroups, and 31 other bacterial strains representing 18 different species. A collection of 647 cattle lymph node samples from steers procured from the Midwest region of the US were tested by the qPCR, and compared to culture-method of detection. Salmonella prevalence by qPCR for pre-enriched and enriched lymph nodes was 19.8% (128/647) and 94.9% (614/647), respectively. A majority of qPCR positive pre-enriched samples (105/128) were at concentrations between 104 and 105 CFU/mL. Culture method detected Salmonella in 7.7% (50/647) and 80.7% (522/647) of pre- and post-enriched samples, respectively; 96.0% (48/50) of pre-enriched and 99.4% (519/522) of post-enriched culture-positive samples were also positive by qPCR. More samples tested positive by qPCR than by culture method, indicating that the real-time PCR assay was more sensitive. Our data indicate that this triplex qPCR can be used to accurately detect and quantify Salmonella enterica strains from cattle lymph node samples. The assay may serve as a useful tool to monitor the prevalence of Salmonella in beef production systems.


Assuntos
Proteínas de Bactérias/genética , Doenças dos Bovinos/diagnóstico , Linfonodos/microbiologia , Proteínas de Membrana/genética , Reação em Cadeia da Polimerase Multiplex/métodos , Reação em Cadeia da Polimerase em Tempo Real/métodos , Salmonelose Animal/diagnóstico , Animais , Bovinos , Doenças dos Bovinos/microbiologia , RNA Ribossômico 18S/genética , Salmonelose Animal/microbiologia , Salmonella enterica/genética , Salmonella enterica/isolamento & purificação , Sensibilidade e Especificidade , Estados Unidos
19.
Am J Trop Med Hyg ; 98(3): 883-890, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29363456

RESUMO

The objective of this work was to summarize and quantify Japanese encephalitis virus (JEV) infection, dissemination, and transmission rates in mosquitoes, using a meta-analysis approach. Data were obtained from experimental studies, gathered by means of a systematic review of the literature. Random-effects subgroup meta-analysis models by mosquito species were fitted to estimate pooled estimates and to calculate the variance between studies for three outcomes of interest: JEV infection, dissemination, and transmission rates in mosquitoes. To identify sources of heterogeneity among studies and to assess the association between different predictors (mosquito species, virus administration route, incubation period, and diagnostic method) with the outcome JEV infection rate in vectors, we fitted univariable meta-regression models. Mosquito species and administration route represented the main sources of heterogeneity associated with JEV infection rate in vectors. This study provided summary effect size estimates to be used as reference for other investigators when assessing transmission efficiency of vectors and explored sources of variability for JEV infection rates in vectors. Because transmission efficiency, as part of vector competence assessment, is an important parameter when studying the relative contribution of vectors to JEV transmission, our findings contribute to further our knowledge, potentially moving us toward more informed and targeted actions to prevent and control JEV in both affected and susceptible regions worldwide.


Assuntos
Aedes/virologia , Culex/virologia , Encefalite Japonesa/transmissão , Modelos Estatísticos , Mosquitos Vetores/virologia , Ochlerotatus/virologia , Animais , Ásia/epidemiologia , Vírus da Encefalite Japonesa (Espécie)/patogenicidade , Vírus da Encefalite Japonesa (Espécie)/fisiologia , Encefalite Japonesa/epidemiologia , Feminino , Humanos
20.
Prev Vet Med ; 147: 163-171, 2017 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-29254715

RESUMO

The objective of this study was to illustrate the implementation of a mixed-model-based structural equation modeling (SEM) approach to observational data in the context of feedlot production systems. Different from traditional multiple-trait models, SEMs allow assessment of potential causal interrelationships between outcomes and can effectively discriminate between direct and indirect effects. For illustration, we focused on feedlot performance and its relationship to health outcomes related to Bovine Respiratory Disease (BRD), which accounts for approximately 75% of morbidity and 50-80% of deaths in feedlots. Our data consisted of 1430 lots representing 178,983 cattle from 9 feedlot operations located across the US Great Plains. We explored functional links between arrival weight (AW; i = 1), BRD-related treatment costs (Trt$; as a proxy for health; i = 2) and average daily weight gain (ADG; as an indicator of productive performance i = 3), accounting for the fixed effect of sex and correlation patterns due to the clustering of lots within feedlots. We proposed competing plausible causal models based on expert knowledge. The best fitting model selected for inference supported direct effects of AW on ADG as well as indirect effects of AW on ADG mediated by Trt$. Direct effects from outcome i' to outcome i are quantified by the structural coefficient λii', such that every unit increase in kg/head of AW had a direct effect of increasing ADG by approximately (estimate ±â€¯standard error) λˆ31=0.002±0.0001 kg/head/day and also a direct effect of reducing Trt$ by an estimated λˆ21=$0.08±0.006 USD per head. In addition, every $1 USD spent on Trt$ directly decreased ADG by an estimated λˆ32=0.004±0.0006 kg/head/day. From these estimates, we show how to compute the indirect, Trt$-mediated, effect of AW on ADG, as well as the overall effect of AW on ADG, including both direct and indirect effects. We further compared estimates of SEM-based effects with those obtained from standard linear regression mixed models and demonstrated the additional advantage of explicitly distinguishing direct and indirect components of an overall regression effect using SEMs. Understanding the direct and indirect mechanisms of interplay between health and performance outcomes may provide valuable insight into production systems.


Assuntos
Criação de Animais Domésticos/métodos , Complexo Respiratório Bovino/prevenção & controle , Animais , Bovinos , Meio-Oeste dos Estados Unidos , Modelos Teóricos , Fatores de Risco , Ganho de Peso
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