Mycoplasma Hyopneumoniae In Pigs Research Articles

Multifrequency Electrical Impedance Tomography Images for Swine Pneumonia Detection Using Conductivity Differences

This article introduces a new MfEIT UDESC Mark I system, which consists of a 32-electrode setup featuring a modified Howland current source, low cost, portability, and non-radiation. The system is capable of reconstructing electrical conductivity tomographic images at a rate of 30.624 frames per second, taking about 5 min for imaging. The current source employs a 0.5 mA adjacent current application pattern with frequencies ranging from 10 kHz to 1 MHz. This article outlines the hardware, firmware, and software design specifications, which include the design of the current source, calibration procedures, and image reconstruction process. Tomographic images of conductivity were reconstructed in ex vivo healthy pig lungs and those with pneumonia, as a proof of concept for future applications in live pigs. The high spectral power density, combined with real-time system calibration provides clinical advantages in veterinary medicine. The goal is to identify lung areas affected by Mycoplasma hyopneumoniae in pigs through the analysis of electrical conductivity difference, offering a valuable tool to assist veterinarians to obtain images of respiratory diseases. The modified reconstruction method GREIT (EIDORS) was evaluated with experimental data and was compared with the Gauss–Newton and Total Variation methods, where GREIT 2D proved to be superior.

Influence of genetics and the pre-vaccination blood transcriptome on the variability of antibody levels after vaccination against Mycoplasma hyopneumoniae in pigs

BackgroundThe impact of individual genetic and genomic variations on immune responses is an emerging lever investigated in vaccination strategies. In our study, we used genetic and pre-vaccination blood transcriptomic data to study vaccine effectiveness in pigs.ResultsA cohort of 182 Large White pigs was vaccinated against Mycoplasma hyopneumoniae (M. hyo) at weaning (28 days of age), with a booster 21 days later. Vaccine response was assessed by measuring seric M. hyo antibodies (Ab) at 0 (vaccination day), 21 (booster day), 28, 35, and 118 days post-vaccination (dpv). Inter-individual variability of M. hyo Ab levels was observed at all time points and the corresponding heritabilities ranged from 0.46 to 0.57. Ab persistence was higher in females than in males. Genome-wide association studies with a 658 K SNP panel revealed two genomic regions associated with variations of M. hyo Ab levels at 21 dpv at positions where immunity-related genes have been mapped, DAB2IP on chromosome 1, and ASAP1, CYRIB and GSDMC on chromosome 4. We studied covariations of Ab responses with the pre-vaccination blood transcriptome obtained by RNA-Seq for a subset of 82 pigs. Weighted gene correlation network and differential expression analyses between pigs that differed in Ab responses highlighted biological functions that were enriched in heme biosynthesis and platelet activation for low response at 21 dpv, innate antiviral immunity and dendritic cells for high response at 28 and 35 dpv, and cell adhesion and extracellular matrix for high response at 118 dpv. Sparse partial least squares discriminant analysis identified 101 genes that efficiently predicted divergent responders at all time points. We found weak negative correlations of M. hyo Ab levels with body weight traits, which revealed a trade-off that needs to be further explored.ConclusionsWe confirmed the influence of the host genetics on vaccine effectiveness to M. hyo and provided evidence that the pre-vaccination blood transcriptome co-varies with the Ab response. Our results highlight that both genetic markers and blood biomarkers could be used as potential predictors of vaccine response levels and more studies are required to assess whether they can be exploited in breeding programs.

Early Detection of Mycoplasma hyopneumoniae in Pigs under Field Conditions Using Tracheo-bronchial Swab Sampling

Early Detection of Mycoplasma hyopneumoniae in Pigs under Field Conditions Using Tracheo-bronchial Swab Sampling

Influence of pig gut microbiota on Mycoplasma hyopneumoniae susceptibility

This study investigated the influence of gut microbiome composition in modulating susceptibility to Mycoplasma hyopneumoniae in pigs. Thirty-two conventional M. hyopneumoniae free piglets were randomly selected from six different litters at 3 weeks of age and were experimentally inoculated with M. hyopneumoniae at 8 weeks of age. Lung lesion scores (LS) were recorded 4 weeks post-inoculation (12 weeks of age) from piglet lungs at necropsy. Fecal bacterial community composition of piglets at 3, 8 and 12 weeks of age were targeted by amplifying the V3–V4 region of the 16S rRNA gene. The LS ranged from 0.3 to 43% with an evident clustering of the scores observed in piglets within litters. There were significant differences in species richness and alpha diversity in fecal microbiomes among piglets within litters at different time points (p < 0.05). The dissimilarity matrices indicated that at 3 weeks of age, the fecal microbiota of piglets was more dissimilar compared to those from 8 to 12 weeks of age. Specific groups of bacteria in the gut that might predict the decreased severity of M. hyopneumoniae associated lesions were identified. The microbial shift at 3 weeks of age was observed to be driven by the increase in abundance of the indicator family, Ruminococcaceae in piglets with low LS (p < 0.05). The taxa, Ruminococcus_2 having the highest richness scores, correlated significantly between litters showing stronger associations with the lowest LS (r = −0.49, p = 0.005). These findings suggest that early life gut microbiota can be a potential determinant for M. hyopneumoniae susceptibility in pigs.

Antimicrobial susceptibility monitoring of Mycoplasma hyopneumoniae and Mycoplasma bovis isolated in Europe

Mycoplasma hyopneumoniae in pigs and Mycoplasma bovis in cattle are major pathogens affecting livestock across Europe and are the focus of the MycoPath pan-European antimicrobial susceptibility monitoring programme. Fifty M. hyopneumoniae isolates from Belgium, Spain and the United Kingdom (UK), and 156 M. bovis isolates from France, Hungary, Spain and the UK that met specific criteria were tested for antimicrobial susceptibility in a central laboratory by using a microbroth dilution method. Specific isolate criteria included recovery from animals not recently treated with antimicrobials, isolates from different locations within each country and retaining only one isolate per farm. MIC50/MIC90 values were 0.031/0.5, 0.031/0.5, 0.062/0.25, ≤0.001/0.004, 0.031/0.125, 0.25/0.5 and 0.062/0.25mg/L for enrofloxacin, marbofloxacin, spiramycin, tulathromycin, tylosin, florfenicol and oxytetracycline respectively against M. hyopneumoniae and 0.25/4, 1/4, 4/16, >64/ >64, 32/ >64, 2/4 and 4/64mg/L, respectively against M. bovis. MIC50/MIC90 values for tiamulin and valnemulin against M. hyopneumoniae were 0.016/0.062 and ≤0.001/ ≤0.001mg/L respectively. The MIC50/MIC90 values of danofloxacin and gamithromycin for M. bovis were 0.25/1 and >64/ >64mg/L respectively. The highest MIC90 values for M. hyopneumoniae were found in the UK at 1.0mg/L for enrofloxacin, marbofloxacin and florfenicol. In contrast, for M. bovis the lowest MIC90 value was 1.0mg/L, but ranged to >64mg/L. Specific laboratory standards and clinical breakpoints for veterinary Mycoplasma species are required as no independently validated clinical breakpoints are specified for veterinary Mycoplasma species, which makes data interpretation and correlation to in vivo efficacy difficult.

Current Status of &amp;lt;i&amp;gt;M. hyopneumoniae&amp;lt;/i&amp;gt; in Pigs in Grenada, West Indies

Mycoplasma hyopneumoniae, cause of enzootic pneumonia is known for serious economic losses in pigs. The disease is prevalent all over the world. There is no published report on Mycoplasma hyopneumoniae incidence in Grenadian pigs. The aim of this study was to estimate seroprevalence of antibodies for Mycoplasma hyopneumoniae in non vaccinated pigs in Grenada. Sera were collected randomly from 459 pigs of all ages from all six parishes of Grenada. Sera were tested for antibodies to Mycoplasma hyopneumoniae using an indirect Enzyme Linked Immunosorbant Assay (ELISA) kit. Antibodies to Mycoplasma hyopneumoniae were found in 8.71% (95% CI: 0.0644 to 0.1167) pigs. The greatest percent of positives (62.5%) (95% CI: 0.4699 to 0.7582) were in youngest group 22.5% (95% CI: 0.1211 to 0.3771) in >2 year. Positive females were overrepresented compared to males by 3:1. This is the first report on the sero-prevalence of Mycoplasma hyopneumoniae in pigs from Grenada, West Indies.

Genotype distribution of Mycoplasma hyopneumoniae in swine herds from different geographical regions

Genetic heterogeneity of Mycoplasma hyopneumoniae in pigs has been reported, however there has been limited reproducibility on the molecular methods employed so far. The aim of this study was to modify and standardize a high-resolution multiple locus variable number tandem repeat analysis (MLVA), to investigate the genetic variability of M. hyopneumoniae circulating in the United States of America (USA), Brazil, Mexico and Spain. The MLVA was standardized on the basis of the number of tandem repeats in two Mycoplasma adhesins, P97 and P146, which are proteins involved in the adherence of the pathogen to cilia. A total of 355 samples obtained from the four countries were analyzed. The Simpson's diversity index for the assay was D=0.976 when samples from all countries were combined. A large number of MLVA types (n=139) were identified, suggesting that multiple M. hyopneumoniae variants are circulating in swine. The locus P97 had 17 different types with 2–18 repeats. The P146 locus showed higher heterogeneity, with 34 different types, ranging from 7 to 48 repeats. MLVA types that presented more than 30 repeats in P146 were found in Spain and Brazil, while shorter repeats were observed in the USA and Mexico. This simplified MLVA method proved to be an efficient tool for typing M. hyopneumoniae with a high degree of stability, repeatability, and discriminatory power. In conclusion, M. hyopneumoniae showed a high variable number tandem repeat heterogeneity and this assay can be applied in molecular epidemiology investigations within farms and productions systems.

DETERMINACIÓN SEROLÓGICA DE LA INFECCIÓN CON Mycoplasma hyopneumoniae EN UNA GRANJA PORCINA DE LIMA

A serological study was conducted to identify the age of highest infection with Mycoplasma hyopneumoniae in pigs under an intensive rearing system in the Lima province, during the period April – August, 2002. Blood samples were collected fortnightly from birth till 16 months of age in 30 piglets. The commercial test ELISA Chekit®-Hyoptest- II was used for the detection of antibodies. The 66.3% (20/30) of the animals showed antibodies against M. hyopneumoniae. The critical period for starting the infection occurred at 9-10 weeks of age. Sex and number of parturition did not affect the time of initial infection.

Seroprevalence of Mycoplasma hyopneumoniae in pigs in subtropical southern China

Enzootic pneumonia caused by Mycoplasma hyopneumoniae is a severe disease of pigs, causing significant economic losses to the pig industry worldwide, including the tropical and subtropical regions. In order to obtain the baseline prevalence of M. hyopneumoniae in pigs from intensive farms in southern China, double-sandwich enzyme-linked immunosorbent assay (ELISA) was used to detect M. hyoneumoniae antibodies in 460 pig serum samples collected from 12 administrative cities in China's southern Guangdong province. According to the proportions of the infected animals, among the 12 intensive farms, only two of them showed no infection of M. hyoneumoniae and the seroprevalence ranged from 0% to 90%, with an averaged prevalence of 45.7%. The highest prevalence was found in breeding boars (68.8%), followed by sows (54.5%). These data showed that the infection of pigs with M. hyopneumoniae is severe, and boars might be more important carriers and transfers of M. hyoneumoniae than sows. Integrated strategies and measures should be taken to control the infection of pigs with M. hyopneumoniae in southern China.

The effect of vaccination on the transmission of Mycoplasma hyopneumoniae in pigs under field conditions

This study investigated the effect of vaccination against Mycoplasma hyopneumoniae on its transmission in nursery pigs under field conditions. Seventy-two pigs were randomly allocated at weaning into vaccinated (V) and non-vaccinated (NV) groups. Animals in the V group were vaccinated at 3 weeks of age with a commercial M. hyopneumoniae bacterin vaccine. Broncho-alveolar lavage fluid taken at weaning and at the end of the nursery period was assessed for the presence of M. hyopneumoniae by nested PCR, and the reproduction ratio of infection (R(n)) was calculated. The percentage of positive pigs in the V and NV groups was 14% and 36% at weaning, and 31% and 64% at the end of the nursery period, respectively. The R(n)-values for the V and NV groups were 0.71 and 0.56, respectively (P>0.05). The study indicates that vaccination does not significantly reduce the transmission of this respiratory pathogen.

Detection of Mycoplasma hyopneumoniae in Pigs in Turkey

Mycoplasma hyopneumoniae is the primary agent of enzootic pneumonia in pigs. The aim of this study was to investigate the occurrence of M. hyopneumoniae in pigs raised in Turkey. Samples were obtained from the lungs of 286 pigs, which had already been separated from the carcasses at slaughter. Lung tissues were homogenized in 5 ml of Friis medium, the suspensions were inoculated into Friis medium, and then incubated at 37 °C until they developed an acid color change or for 21 days. Cultures were identified by M. hyopneumoniae-specific PCR. M. hyopneumoniae was recovered from 2 (0.70%) of the 286 lung samples. This study is the first to report the isolation of M. hyopneumoniae in pigs in Turkey.

Detection of Mycoplasma hyopneumoniae in Pigs in Turkey

Mycoplasma hyopneumoniae is the primary agent of enzootic pneumonia in pigs. The aim of this study was to investigate the occurrence of M. hyopneumoniae in pigs raised in Turkey. Samples were obtained from the lungs of 286 pigs, which had already been separated from the carcasses at slaughter. Lung tissues were homogenized in 5 ml of Friis medium, the suspensions were inoculated into Friis medium, and then incubated at 37 °C until they developed an acid color change or for 21 days. Cultures were identified by M. hyopneumoniae-specific PCR. M. hyopneumoniae was recovered from 2 (0.70%) of the 286 lung samples. This study is the first to report the isolation of M. hyopneumoniae in pigs in Turkey.

Seroepidemiology of Mycoplasma hyopneumoniae in pigs from farrow-to-finish farms

A prospective study was carried out on three intensive farrow-to-finish farms. The aims were to estimate the incidence of Mycoplasma hyopneumoniae infection, to determine when pigs become infected and the pattern of transmission of infection and to verify the relationship between seroconversion and clinical signs. One batch of pigs per farm was followed from farrowing-to-slaughter. Blood samples were taken at 10, 27, 70, 94, 125 and 147 days of age, from 44, 48 and 44 pigs per farm. Colostrum and blood samples were also taken from the sows. Animals were checked clinically once a week and coughing rates were recorded. Antibodies against M. hyopneumoniae were detected by a blocking ELISA. At 27, 70 and 94 days of age most pigs on the three farms were seronegative, suggesting that no circulation of M. hyopneumoniae occurred during the growing period. Thereafter, a high proportion of pigs seroconverted, indicating that infection occurred soon after the transfer of the animals to the finishing houses. Differences were detected between farms in the incidence of seroconversion. Seropositive pigs were widely distributed among the finishing pens, suggesting that in addition to direct contact, other methods of transmission, such as indirect or airborne transmission, may have been important. Coughing started at around the same time as seroconversion. The results showed that the critical period for the transmission of M. hyopneumoniae is around the beginning of the finishing period, when pigs have low concentrations of antibodies against the agent.

An improved enzyme linked immunosorbent assay (ELISA) for the detection of porcine serum antibodies against Mycoplasma hyopneumoniae

An ELISA for the detection of serum antibodies to Mycoplasma hyopneumoniae in pigs and based on a 43 kDa purified protein derived from the cytoplasmic membrane of M. hyopneumoniae strain J is described. This ELISA (MHPP ELISA) was compared with another recently described (Auspharm ELISA, Sheldrake and Romalis 1992) that is based on column-purified sonicated proteins of strain J. Using sample to negative ELISA ratios of 3 and 4 as cutoffs for inconclusive and positive reactors respectively (compared to 2 and 3 for the Auspharm ELISA), the two tests had high specificity (MHPP 99.6%; Auspharm 100%) in 280 SPF pigs. In 176 pigs from commercial herds with endemic M. hyopneumoniae, the MHPP ELISA showed a higher sensitivity than the Auspharm ELISA in both high lung score (LS ≥ 5) (85.5% vs. 69.9%) and low lung score (0 < LS < 5) (57.9% vs. 49%) pigs when the positive cutoff for each test was selected. The sensitivity when the inconclusive cutoff was selected was similar in both tests (85%; 85.7%) when low and high lung score pigs were pooled. Although the MHPP also gave more positive reactors in 36 pigs from M. hyopneumoniae-infected herds with no lung pathology at slaughter than the Auspharm ELISA (11 vs. 4), the total number of inconclusive and positive reactors in these pigs was similar for both tests (18 vs. 14). The MHPP ELISA gave significantly higher ELISA ratios in infected pigs (up to 17.9) than the Auspharm ELISA (up to 9), and earlier seroconversion in naturally-infected (6–8 weeks vs. 9–10 weeks) and experimentally-infected pigs (2–4 weeks vs. 4–6 weeks post infection).