The effect of vaccination on the transmission of Mycoplasma hyopneumoniae in pigs under field conditions.
TL;DR: It is indicated that vaccination does not significantly reduce the transmission of this respiratory pathogen in nursery pigs under field conditions.
Abstract: 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 (Rn) 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 Rn-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.
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TL;DR: The present paper reviews the current knowledge on M. hyopneumoniae infections, with emphasis on identification and analysis of knowledge gaps for optimizing control of the disease.
Abstract: Mycoplasma hyopneumoniae (M. hyopneumoniae) is the primary pathogen of enzootic pneumonia, a chronic respiratory disease in pigs. Infections occur worldwide and cause major economic losses to the pig industry. The present paper reviews the current knowledge on M. hyopneumoniae infections, with emphasis on identification and analysis of knowledge gaps for optimizing control of the disease. Close contact between infected and susceptible pigs is the main route of M. hyopneumoniae transmission. Management and housing conditions predisposing for infection or disease are known, but further research is needed to better understand M. hyopneumoniae transmission patterns in modern pig production systems, and to assess the importance of the breeding population for downstream disease control. The organism is primarily found on the mucosal surface of the trachea, bronchi and bronchioles. Different adhesins and lipoproteins are involved in the adherence process. However, a clear picture of the virulence and pathogenicity of M. hyopneumoniae is still missing. The role of glycerol metabolism, myoinositol metabolism and the Mycoplasma Ig binding protein-Mycoplasma Ig protease system should be further investigated for their contribution to virulence. The destruction of the mucociliary apparatus, together with modulating the immune response, enhances the susceptibility of infected pigs to secondary pathogens. Clinical signs and severity of lesions depend on different factors, such as management, environmental conditions and likely also M. hyopneumoniae strain. The potential impact of strain variability on disease severity is not well defined. Diagnostics could be improved by developing tests that may detect virulent strains, by improving sampling in live animals and by designing ELISAs allowing discrimination between infected and vaccinated pigs. The currently available vaccines are often cost-efficient, but the ongoing research on developing new vaccines that confer protective immunity and reduce transmission should be continued, as well as optimization of protocols to eliminate M. hyopneumoniae from pig herds.
182 citations
Cites background from "The effect of vaccination on the tr..."
...However, studies under experimental (Meyns et al., 2006) and field conditions (Pieters, Fano, Pijoan, & Dee, 2010; Villarreal et al., 2011b) showed that vaccination conferred only a limited reduction in the transmission ratio of M. hyopneumoniae....
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...…dose of M. hyopneumoniae, lung lesions and onset of coughing can appear as early as 7–14 days post-infection (dpi; Blanchard et al., 1992; Lorenzo, Quesada, Assuncao, Castro, & Rodr ıguez, 2006), with maximum severity and extension of lung lesions occurring around 28 dpi (Villarreal et al., 2011a)....
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...…data have shown that transmission of M. hyopneumoniae among pen-mates is slow (Meyns et al., 2004; Roos, Fano, Homwong, Payne, & Pieters, 2016; Villarreal et al., 2011b), fitting the picture that disease presentation can be the result of early group colonization and subsequent transmission…...
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TL;DR: The findings indicate that M. hyopneumoniae, PRRSV and SIV H1N1 are the major pathogens involved in pneumonia-like gross lesions even though PCV2 may play a role.
140 citations
Cites background or result from "The effect of vaccination on the tr..."
...Villarreal et al. (2011) studied 52 farms clinically affected by respiratory diseases in nine European countries and found that at least one 3-week-old piglet was infected by M. hyopneumoniae in 68% of the herds....
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...Furthermore, experimental and field studies have indicated that M. hyopneumoniae vaccination does not significantly reduce transmission of the pathogen (Meyns et al., 2006; Villarreal et al., 2011)....
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...hyopneumoniae vaccination does not significantly reduce transmission of the pathogen (Meyns et al., 2006; Villarreal et al., 2011)....
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TL;DR: An assay based on multiple-locus variable-number tandem-repeat analysis allowed differentiating and studying diversity and persistence of Mycoplasma hyopneumoniae strains in pig herds without prior cultivation.
Abstract: An assay based on multiple-locus variable-number tandem-repeat analysis allowed differentiating and studying diversity and persistence of Mycoplasma hyopneumoniae strains in pig herds without prior cultivation. The test had a discriminatory index of >0.99 and was applied reliably to porcine bronchoalveolar lavage fluid and tracheal swabs.
52 citations
Cites methods from "The effect of vaccination on the tr..."
...tained from the right lung as previously described (14)....
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TL;DR: Although 125 non homologous and predicted essential proteins were found from the total that could serve as potential drug targets and vaccine candidates, additional prioritizing parameters characterize 21 proteins as vaccine candidate while druggability of each of the identified proteins evaluated by the DrugBank database prioritized 42 proteins suitable for drug targets.
42 citations
TL;DR: The infiltration of macrophages after infection with M. hyopneumoniae is reduced by vaccination and replication in the lungs is also reduced in vaccinated pigs, though the HV strain is inhibited more than the LV strain.
Abstract: Mycoplasma hyopneumoniae is the causative agent of enzootic pneumonia and is responsible for significant economic losses to the pig industry. To better understand the mode of action of a commercial, adjuvanted, inactivated whole cell vaccine and the influence of diversity on the efficacy of vaccination, we investigated samples from vaccinated and non-vaccinated pigs experimentally infected with either a low (LV) or a highly virulent (HV) M. hyopneumoniae strain. Non-vaccinated and sham-infected control groups were included. Lung tissue samples collected at 4 and 8 weeks post infection (PI) were immunohistochemically tested for the presence of T-lymphocytes, B-lymphocytes and macrophages in the bronchus-associated lymphoid tissue (BALT). The number of M. hyopneumoniae organisms in bronchoalveolar lavage (BAL) fluid was determined using quantitative PCR at 4 and 8 weeks PI. Serum antibodies against M. hyopneumoniae were determined at 0, 2, 4, 6 and 8 weeks PI. The immunostaining revealed a lower density of macrophages in the BALT of the vaccinated groups compared to the non-vaccinated groups. The highest number of M. hyopneumoniae organisms in the BAL fluid was measured at 4 weeks PI for the HV strain and at 8 weeks PI for the LV strain. Vaccination reduced the number of organisms non-significantly, though for the HV strain the reduction was clinically more relevant than for the LV strain. At the level of the individual pigs, a higher lung lesion score was associated with more M. hyopneumoniae organisms in the lungs and a higher density of the investigated immune cells in the BALT. In conclusion, the infiltration of macrophages after infection with M. hyopneumoniae is reduced by vaccination. The M. hyopneumoniae replication in the lungs is also reduced in vaccinated pigs, though the HV strain is inhibited more than the LV strain.
33 citations
Cites background from "The effect of vaccination on the tr..."
...However, there is no or only limited effect on the transmission of this organism [12,13]....
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References
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01 Jan 1994
TL;DR: General techniques laboratory safety collection and submission of diagnostic specimens essential equipment and reagents for a veterinary diagnostic microbiology laboratory diagnostic applications of immunological tests
Abstract: General techniques laboratory safety collection and submission of diagnostic specimens essential equipment and reagents for a veterinary diagnostic microbiology laboratory diagnostic applications of immunological tests bacterial pathogens - microscopy, culture and identification the isolation and identification of viral pathogens antimicrobial agents bacteriology staphylococci streptococci corynebacteria and rhodococcus equi actinomycetes, myobacteria, listeria species erysipelothrix species bacillus species clostridia non spore-forming anaerobes enterobacteriaceae pseudomonas species aeromonas and plesiomonas species actinobacillus species pasteurella species francisella tuiarensis brucella species moraxella species miscellaneous non-fermenters spirochaetes miscellaneous gram-negative bacteria chlamydiae rickettsiae mycoplasma species mastitis food poisoning mycology - general aspects dermatophytes aspergillus species pathogenic yeasts dimorphic fungi zygomycetes miscellaneous pathogenic fungi mycotoxicoses virology viral diseases unconventional viruses (prions) kit-set tests available for virology zoonoses control of infectious diseases a systems approach to infectious diseases of domestic animals.
1,576 citations
TL;DR: The main effects of vaccination include less clinical symptoms, lung lesions and medication use, and improved performance, however, bacterins provide only partial protection and do not prevent colonization of the organism.
370 citations
TL;DR: Results indicate that M. hyopneumoniae infection potentiates PRRSV-induced disease and lesions, which is important with respect to the control of respiratory disease in pigs and has implications in elucidating the potential contribution of mycoplasmas in the pathogenesis of viral infections of other species, including humans.
Abstract: An experimental model that demonstrates a mycoplasma species acting to potentiate a viral pneumonia was developed. Mycoplasma hyopneumoniae, which produces a chronic, lymphohistiocytic bronchopneumonia in pigs, was found to potentiate the severity and the duration of a virus-induced pneumonia in pigs. Pigs were inoculated with M. hyopneumoniae 21 days prior to, simultaneously with, or 10 days after inoculation with porcine reproductive and respiratory syndrome virus (PRRSV), which induces an acute interstitial pneumonia in pigs. PRRSV-induced clinical respiratory disease and macroscopic and microscopic pneumonic lesions were more severe and persistent in M. hyopneumoniae-infected pigs. At 28 or 38 days after PRRSV inoculation, M. hyopneumoniae-infected pigs still exhibited lesions typical of PRRSV-induced pneumonia, whereas the lungs of pigs which had received only PRRSV were essentially normal. On the basis of macroscopic lung lesions, it appears that PRRSV infection did not influence the severity of M. hyopneumoniae infection, although microscopic lesions typical of M. hyopneumoniae were more severe in PRRSV-infected pigs. These results indicate that M. hyopneumoniae infection potentiates PRRSV-induced disease and lesions. Most importantly, M. hyopneumoniae-infected pigs with minimal to nondetectable mycoplasmal pneumonia lesions manifested significantly increased PRRSV-induced pneumonia lesions compared to pigs infected with PRRSV only. This discovery is important with respect to the control of respiratory disease in pigs and has implications in elucidating the potential contribution of mycoplasmas in the pathogenesis of viral infections of other species, including humans.
344 citations
TL;DR: The experiments showed that vaccinating twice with vaccine 783 significantly reduces ADV transmission, and showed that it is possible to measure transmission experimentally, and should be obtained for all vaccines that are intended to eliminate agents causing animal diseases.
206 citations
TL;DR: The current state of knowledge of the epidemiology of M. hyopneumoniae infection including its transmission, infection and seroconversion dynamics is reviewed and the various epidemiological tools used to monitor EP are compared.
Abstract: Mycoplasma hyopneumoniae is the principal aetiological agent of enzootic pneumonia (EP), a chronic respiratory disease that affects mainly finishing pigs. Although major efforts to control M. hyopneumoniae infection and its detrimental effects have been made, significant economic losses in pig production worldwide due to EP continue. M. hyopneumoniae is typically introduced into pig herds by the purchase of subclinically infected animals or, less frequently, through airborne transmission over short distances. Once in the herd, M. hyopneumoniae may be transmitted by direct contact from infected sows to their offspring or between pen mates. The 'gold standard' technique used to diagnose M. hyopneumoniae infection, bacteriological culture, is laborious and is seldom used routinely. Enzyme-linked immunosorbent assay and polymerase chain reaction detection methods, in addition to post-mortem inspection in the form of abattoir surveillance or field necropsy, are the techniques most frequently used to investigate the potential involvement of M. hyopneumoniae in porcine respiratory disease. Such techniques have been used to monitor the incidence of M. hyopneumoniae infection in herds both clinically and subclinically affected by EP, in vaccinated and non-vaccinated herds and under different production and management conditions. Differences in the clinical course of EP at farm level and in the efficacy of M. hyopneumoniae vaccination suggest that the transmission and virulence characteristics of different field isolates of M. hyopneumoniae may vary. This paper reviews the current state of knowledge of the epidemiology of M. hyopneumoniae infection including its transmission, infection and seroconversion dynamics and also compares the various epidemiological tools used to monitor EP.
177 citations