Best of Leman 2017 series #7: P. Yeske – Assessment of the likelihood of Mycoplasma hyopneumoniae lateral transmission

We launched a new series on the blog in October. Once a month, we are sharing with you a presentation given at the 2017 Allen D. Leman swine conference, on topics that the swine group found interesting, innovative or that lead to great discussions.

Our seventh presentation is by Dr. Paul Yeske from Swine Vet Center regarding the likelihood of lateral transmission of Mycoplasma hyopneumoniae.

To listen to this talk, please click on the image below.

Yeske Mycoplasma hyopneumoniae lateral transmission

Acclimation strategies in gilts to control Mycoplasma hyopneumoniae infection

Today we are sharing a review article regarding the acclimation strategies in gilts to control Mycoplasma hyopneumoniae infection published in Veterinary Microbiology by  the University of Barcelona in collaboration with Dr. Maria Pieters.

Key points

  • M. hyopneumoniae monitoring should be performed in incoming gilts and recipient herd.
  • Gilt acclimation against M. hyopneumoniae aids to maintain farm health stability.
  • Vaccination is the main strategy used to acclimate gilts in Europe and North America

Monitoring and diagnosis of M.hyopneumoniae

The article first covers how to assess the M. hyopneumoniae health status of the herd. Various methods of monitoring and diagnosis are detailed and compared with each other.

  • Most commonly used: M. hyopneumoniae antibody detection by ELISA but the interpretation of the results can be challenging.
  • Most useful technique: PCR on different respiratory tract samples.
  • No consensus on sample type to detect bacterial DNA in live pigs.

Classification of the herd based on incoming replacement and recipient herd

 

Proposed farm classification according to M. hyopneumoniae health status. (aELISA results (negative/positive) could depend on infection pattern in the farm and sampling time point.)

Classification


Clinical signs Lung lesions ELISA resulta PCR result
Negative Not observed Not observed Negative Negative
Provisional negative Not observed Not observed Positive Negative
Positive Subclinical infected I Not observed Not observed Positive/Negative Positive
Subclinical infected II Not observed Observed Positive/Negative Positive
Clinical affected Observed Observed Positive/Negative Positive

Prevention and control

Vaccination against M. hyopneumoniae, using commercial vaccines, is the most commonly used strategy to control its associated diseases in worldwide swine production systems.

However, since protection against M. hyopneumoniae infection by commercial vaccines is not complete, antimicrobial treatments are frequently required to control disease outcome. Several antibiotic classes are effective in reducing the incidence and severity of M. hyopneumoniae compatible lung lesions: macrolides, lincosamides, tetracycline, and fluoroquinolones among others.

Acclimation scenarios

Europe

The most common replacement origin used in Europe was external and that most respondents knew M. hyopneumoniae health status of replacement on arrival, being in most of the cases seropositive. Nevertheless, only 28% of respondents verified this theoretical M. hyopneumoniae status given as ELISA test results. Additionally, the most used strategy to acclimate gilt was vaccination alone (58%).

North America

Gilt Development Units are utilized to allow ample time to incoming gilt to gradually adopt the health status of the recipient herd. These acclimation facilities are in most of the cases continuous flow allowing an effective gilt exposure to M. hyopneumoniae. Gilt vaccination in North American swine industry was also recognized as the most common practice used at acclimation.

Natural exposure

Natural exposure was also used in both continents to help acclimate the incoming gilts to  M.hyopneumoniae. However, taking into account that pig-to-pig transmission of this bacterium has proven to be extremely slow , the ratio of infected and naïve gilts as well as the time of exposure are crucial and should be considered to achieve an effective exposure.

 

Abstract

Mycoplasma hyopneumoniae (M. hyopneumoniae) is the primary causative agent of enzootic pneumonia (EP), one of the most economically important infectious disease for the swine industry worldwide. M. hyopneumoniae transmission occurs mainly by direct contact (nose-to-nose) between infected to susceptible pigs as well as from infected dams to their offspring (sow-to-piglet). Since disease severity has been correlated with M. hyopneumoniae prevalence at weaning in some studies, and gilts are considered the main bacterial shedders, an effective gilt acclimation program should help controlling M. hyopneumoniae in swine farms. The present review summarizes the different M. hyopneumoniae monitoring strategies of incoming gilts and recipient herd and proposes a farm classification according to their health statuses. The medication and vaccination programs against M. hyopneumoniae most used in replacement gilts are reviewed as well. Gilt replacement acclimation against M. hyopneumoniae in Europe and North America indicates that vaccination is the main strategy used, but there is a current trend in US to deliberately expose gilts to the pathogen.

 

Controlling Mycoplasma hyopneumoniae infections in the field

Controlling Mycoplasma hyopneumoniae in the field can be challenging. After summarizing the best sample types and diagnostic methods to detect mycoplasma infections early, Dr. Maria Pieters wrote an article for pig333 recapitulating the existing options for a producer struggling with enzootic pneumonia on her farm.

No single strategy will confer total protection. A well-orchestrated combination of various methods adjusted to a single production unit or system will be needed.

Indeed, Dr. Pieters reminds us that 3 different approaches can be combined to achieve greater disease control:

overall-mycoplasma-hyopneumoniae-control-is-effectively-achieved-when-combining-various-strategies_126971.jpgNo single strategy will confer total protection from infection with M. hyopneumoniae or disease elimination. However, a well-orchestrated combination of various methods, not only directed at clinical signs, but to the root of disease spread and transmission, adjusted to the unique characteristics of a production unit or system, is necessary to reach the goal of controlling M. hyopneumoniae infections and improving overall swine production around the world.

The entire article on Controlling Mycoplasma hyopneumoniae in the field is available on the pig333 website.

Sample types and diagnostic methods for early detection of Mycoplasma hyopneumoniae

In lieu of the Science Page today, we are bringing you our most popular articles on the blog this past year: a publication by Dr. Maria Pieters, head of the MycoLab called Sample and diagnostic types for early detection of Mycoplasma hyopneumoniae.

Summary:

Mycoplasma hyopneumoniae is the causative agent enzootic pneumonia, an economically significant disease in pigs. In this study published by Drs. Pieters and Rovira from the University of Minnesota, pigs experimentally inoculated with M.hyopneumoniae were sampled 0, 2, 5, 9, 14, 21, and 28 post-inoculation.

Different sample types were compared:

  • Nasal swabs
  • Laryngeal swabs
  • Tracheobronchal lavages
  • Oral fluids
  • Serum samples

Using different diagnostic tests:

  • PCR
  • ELISA IgG anti M.hyopneumoniae
  • ELISA Ig M anti M.hyopneumoniae
  • ELISA C-reactive protein

Laryngeal swab samples tested by PCR were highly sensitive for detection of Mycoplasma hyopneumoniae in live pigs. Various commercial ELISA kits for detection of Mycoplasma hyopneumoniae antibodies showed similar sensitivity. Oral fluids showed a low sensitivity for detection of Mycoplasma hyopneumoniae in experimentally infected pigs.

Link to the full-article

Best of Leman 2017 series #2: P Yeske – A survival analysis of Mycoplasma hyopneumoniae elimination efforts

We launched a new series on the blog last month. Once a month, we are sharing with you a presentation given at the 2017 Allen D. Leman swine conference, on topics that the swine group found interesting, innovative or that lead to great discussions.

Our second presentation today is from Dr. Paul Yeske from Swine Vet Center, who is coming back on his experience with Mycoplasma hyopneumoniae elimination and giving us an update if the herds stayed negative.

To listen to this presentation, please click on the picture below:

Yeske Survival analysis of Mhyo elimination efforts Leman 2017

Happy Thanksgiving to you and your loved ones!

M.hyopneumoniae: knowledge gaps for improved disease control

Enzootic pneumoniae is a chronic respiratory disease caused by Mycoplasma hyopneumoniae in pigs. It has been present in the industry for decades and causes significant economic losses. Yet, control methods like vaccination have not been able to contain the disease. Why is that? What information are we missing to design more effective control methods? This is the goal of the review paper co-authored by Dr. Maria Pieters from the University of Minnesota.

Focusing on various aspects of the disease like epidemiology, pathogenicity, diagnostics, and control measures, this publication regroups all the knowledge we currently have of Mycoplasma hyopneumoniae and identifies what we need to investigate to improve disease control.

Click on the banner below to access the full article.

Update on Mhyopneumoniae infections in pig Pieters 2017

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.

What are the acclimation practices for Mycoplasma hyopneumoniae accross the EU?

This new publication in the Porcine Health Management journal is the result of a collaboration between the University of Barcelona in Spain, PIC (Pig improvement Company) and the MycoLab at the University of Minnesota.

321 farms were surveyed across Europe and Russia regarding their practices for gilt acclimation especially in the context of Mycoplasma hyopneumoniae. The farms are spread over 18 countries and this is reflected in the strong variation of the measures taken to acclimate the incoming gilt population.

Among the questions asked, the type of farm as well as the size of the herd were recorded. Regarding the gilts, the researchers took into account receiving schedule as well as origin and age in addition to the acclimation measures.

In the table below, you can see the summary of  the measures taken to acclimate the gilts to Mycoplasma hyopneumoniae. The vast majority of the herds (77%) used vaccination either as a single intervention or coupled with exposure to sows about to be culled.  Another popular option (22.4%) was no intervention at all.

Acclimation methods for Mycoplasma hyopneumoniae across the EU
Number of farms (%)according to the methods used for replacement gilt acclimation in terms of M. hyopneumoniae

Click on the table above to see the full open-access publication.

Abstract

Gilts are considered to play a key role in Mycoplasma hyopneumoniae (M.hyopneumoniae) transmission and control. An effective gilt acclimation program should ideally reduce M. hyopneumoniae shedding at first farrowing, decreasing pre-weaning colonization prevalence and potential respiratory problems in fatteners. However, information on gilt acclimation practices is scarce in Europe. The aim of this study was to identify current acclimation strategies for M. hyopneumoniae in Europe using a questionnaire designed to assess 15 questions focused on gilt replacement status,
acclimation strategies and methods used to ascertain its effect. A total of 321 questionnaires (representing 321 farms) were voluntarily completed by 108 veterinarians (from 18 European countries). From these farms, 280 out of 321 (87.2%) were aware of the health status of gilts on arrival. From these 280 farms, 161 (57.5%) introduced M. hyopneumoniae positive replacements. In addition, 249 out of 321 (77.6%) farms applied an acclimation process using different strategies, being M. hyopneumoniae vaccination (145 out of 249, 58.2%) and the combination of vaccine and
exposure to sows selected for slaughter (53 out of 249, 21.3%) the most commonly used. Notwithstanding, only 53 out of 224 (23.6%) farms, knowing the M. hyopneumoniae initial status and performing acclimation strategies against it, verified the effect of the acclimation by ELISA (22 out of 53, 41.5%), PCR (4 out of 53, 7.5%) or both (27 out of 53, 50.9%). This study showed that three fourths of the farms represented in this European survey have M. hyopneumoniae acclimation strategies for gilts, and one fifth of them verify to some extent the effect of the process. Taking into account that the assessment of acclimation efficacy could help in optimizing replacement gilt introduction into the breeding herd, it seems these practices for M. hyopneumoniae are still poorly developed in Europe.

Link to the full open-access publication