Papers by Amanda Sponheim
Canadian Journal of Veterinary Research-revue Canadienne De Recherche Veterinaire, Oct 1, 2020
The aim of this study was to assess the genetic variability of Mycoplasma hyopneumoniae within va... more The aim of this study was to assess the genetic variability of Mycoplasma hyopneumoniae within various swine production flows. Four M. hyopneumoniae positive production flows, composed of 4 production stages, were selected for this study. Laryngeal and/or bronchial swabs were collected from each production stage within a flow, for a period of 4 months up to 3 years. A multiple-locus variable-number tandem repeat analysis was performed to assess the genetic variation of M. hyopneumoniae within and across production flows through the identification of variable-number tandem repeat (VNTR) types. A maximum of 6 M. hyopneumoniae VNTR types were identified in a single flow, in which VNTR types appeared to be flow specific. An identical VNTR type was detected across several production stages for up to 3 years. In this study, minimal M. hyopneumoniae genetic variation was evidenced within and across production flows.
Journal of Veterinary Diagnostic Investigation, May 23, 2019
Detection of PRRSV in processing fluids where one positive animal is mixed with large groups of n... more Detection of PRRSV in processing fluids where one positive animal is mixed with large groups of negative animals is dependent on the level of viremia together with the sex of the positive pig. Theoretically, low Ct values could be pooled/diluted more than 1,000 times and PRRSV could still be detected. Processing fluids aggregation and pooling should be adapted according to the different prevalence scenarios and health goals (e.g eradication vs control).
Microorganisms, Jan 27, 2021
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
AASV Annual Meeting, Feb 16, 2022
Introduction Preventing the spread of PRRS virus (PRRSv) between groups of pigs is a major goal o... more Introduction Preventing the spread of PRRS virus (PRRSv) between groups of pigs is a major goal of pork producers. Many hog operations utilize liquid disinfectant boot baths as a part of biosecurity protocols aimed at minimizing the spread of PRRSv. Several problems arise from the current use of liquid disinfectant boot baths including their effectiveness following contamination with fecal matter and in freezing temperatures. The objective of this study was to test Stalosan F, a powder disinfectant, as an alternative to a liquid disinfectant boot bath, for the deactivation of PRRSv under various temperatures and in the presence or absence of fecal matter.
Preventive Veterinary Medicine, 2021
Early and accurate detection of Mycoplasma hyopneumoniae infection in live pigs is a critical com... more Early and accurate detection of Mycoplasma hyopneumoniae infection in live pigs is a critical component to measure the success of disease eradication strategies. However, the imperfect sensitivity of in vivo diagnostic tools, change in sensitivity over the course of infection, and expected low prevalence level at the end of an eradication program create a challenging diagnostic scenario. Here, the individual and pool sensitivities for detection of M. hyopneumoniae during the chronic phase of infection was determined using deep tracheal catheter samples, the in vivo sample type with the highest reported diagnostic sensitivity. Fifty samples from known infected pigs collected at 113 days post-M. hyopneumoniae intra-tracheal inoculation, were diluted in known negative samples to form pools of 1:3 and 1:5. Samples were tested for M. hyopneumoniae by a species-specific PCR. Ninety-eight percent (49/50) of individual samples, 84 % (42/50) of pools of 1:3, and 82 % (41/50) of 1:5 were detected positive for M. hyopneumoniae. To apply the sensitivity estimates for detection of M. hyopneumoniae in a low prevalence scenario, sample sizes with associated sample collection costs were calculated for individual and pooled testing using algorithms within the program EpiTools One-Stage Freedom Analyses. Assumptions included a ≥95 % population sensitivity, infinite population size, prevalence levels of ≥0.5 %, ≥1 %, ≥2 %, ≥3 %, ≥4 %, or ≥5 %, 100 % specificity, along with the mean and lower confidence limit of the individual or pool sensitivity for each pool size, when appropriate. For instance, following completion of a herd eradication program, if a low risk approach is targeted, sample size estimates for ≥2 % prevalence using the lower limit of the diagnostic or pool sensitivity 95 %CI may be followed. If samples were to be tested individually, 167 individuals would be sampled at a cost of 6,012 USD. If pooled by 3, 213 would be sampled (testing cost 3,266 USD), and for pools of 5, 220 individuals would be sampled (testing cost 2,464 USD). Population sensitivity was also calculated for a range of testing scenarios. Our study indicated that pooling samples by 3 or 5 was a cost-effective method for M. hyopneumoniae detection in low prevalence scenarios. Cost-effective detection was evidenced despite the increased sample collection costs associated with large sample sizes in order to offset decreased testing sensitivity attributable to pooling. The post-eradication sample collection scheme, combined with pooling, suggested lower cost options than individual sampling for testing to be applied at the end of an eradication program, without significantly compromising the likelihood of detection.
Microorganisms, 2021
The association of the lower respiratory tract microbiome in pigs with that of other tissues and ... more The association of the lower respiratory tract microbiome in pigs with that of other tissues and environment is still unclear. This study aimed to describe the microbiome of tracheal and oral fluids, air, and feces in the late stage of Mycoplasma hyopneumoniae infection in pigs, and assess the association between the tracheal microbiome and those from air, feces, and oral fluids. Tracheal fluids (n = 73), feces (n = 71), oropharyngeal fluids (n = 8), and air (n = 12) were collected in seeder pigs (inoculated with M. hyopneumoniae) and contact pigs (113 days post exposure to seeder pigs). After DNA extraction, the V4 region from 16S rRNA gene was sequenced and reads were processed using Divisive Amplicon Denoising Algorithm (DADA2). Clostridium and Streptococcus were among the top five genera identified in all sample types. Mycoplasma hyopneumoniae in tracheal fluids was associated with a reduction of diversity and increment of M. hyorhinis, Glaesserella parasuis, and Pasteurella mul...
Veterinary Microbiology, 2019
Comparison of the sensitivity of laryngeal swabs and deep tracheal catheters for detection of Myc... more Comparison of the sensitivity of laryngeal swabs and deep tracheal catheters for detection of Mycoplasma hyopneumoniae in experimentally and naturally infected pigs early and late after infection, Veterinary Microbiology (2019),
Journal of Veterinary Diagnostic Investigation, 2019
A sampling technique has been validated to monitor porcine reproductive and respiratory syndrome ... more A sampling technique has been validated to monitor porcine reproductive and respiratory syndrome virus 2 (PRRSV-2) using the serosanguinous exudate known as processing fluids (PFs) that accumulate from tissues obtained during tail docking and castration. PFs are an aggregate sample of large numbers of piglets and litters. However, little is known about the effect of litter aggregation on the ability of PCR to correctly classify an aggregated PF sample as positive. We evaluated both the effect of litter aggregation and of PF pooling on PCR detection. We estimated that aggregation of at least 50 litters was possible when a pig with a Ct value of ~22 was present in the sample, and aggregation of up to 40 litters was possible when there was a sample with a Ct value of ~33. Pooling did not affect PCR detection when initial Ct values of 20 and 25 were assessed. However, in litters with initial Ct values of ≥30, the amount of pooling should be reduced. Our results provide producers and pra...
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Papers by Amanda Sponheim