At Lohmann Animal Health International, we take pride in our role as a practical technical partner with poultry producers. This objective has been in place in our company since our Winslow, Maine operation was founded in 1957. Many new disease challenges have emerged and been subsequently brought under control during the past 55 years. During that time, we have been doing our part to help poultry producers prevent the damages caused by those infections.

We pioneered the category of inactivated poultry vaccines and still lead the industry in adjuvant technology. We pioneered inactivated Newcastle vaccine, live infectious Laryngotracheitis vaccine, the first two live Salmonella vaccines and others. We currently have a significant amount of our resources committed to R&D aimed at further advances in disease prevention for the poultry producer.

Mycoplasma gallisepticum and the damage it causes from poor feed

conversion, lower egg production rate, decreased egg quality, increased mortality and morbidity is the subject of our paper for this issue of Avian Insight.

To help chickens continue to produce profitably in the face of this largely eradicated disease, we provide AviPro® 104 MG Bacterin, AviPro® 304 ND-IB-MG and AviPro® MG F live vaccines. In addition, our Technical Service Veterinarians are available to help you program the timing and product for your operation. We at Lohmann Animal Health will team with you to minimize the damages caused by Mycoplasma

gallisepticum. Contact your Lohmann Animal Health representative and learn how we can help you prevent damages from MG and other infectious agents.

Personal note: This will be my last commentary for Avian Insight. I am

moving on to begin a new enterprise within the Lohmann SE Group

called Lohmann Solutions. It is a global consultancy with centers

located around the world, created to support our customers regarding

issues related to production of safe, healthy and sustainable food, such

as prevention of foodborne zoonoses, animal welfare support and

water quality programs. The Vice President and Director of Sales for

the Americas of Lohmann Animal Health International, Inc., Shannon

Kellner will take on the Avian Insight commentary responsibility

beginning with the next issue.

avianinsightA L O H M A N N A N I M A L H E A L T H N E W S B R I E F

Current approaches to MG control

Introduction

Mycoplasma gallisepticum (MG) is one of the lead-ing causes of economic loss to the poultry industry worldwide. The disease affects primarily chickens and turkeys, causing respiratory infections and airsacculitis, as well as egg production drops. The global expansion of the commercial poultry industry has resulted in greater concentrations of susceptible birds in poultry-producing areas, increasing the risk and consequences of MG infection. In the United States, most broiler and turkey production is MG negative. MG prevalence in commercial laying operations, however, is considerably higher, particularly on large multiple-age complexes.

There are three general approaches to MG control: Prevention of infection is ideal, but in situations where this is not considered feasible (eg. multiple-age com-plexes), medication and/or vaccination are options. In this article, we discuss approaches to MG control, fo-cusing on the current situation in the United States. We also review recent findings related to the performance of F strain vaccines.

Control by prevention of infection

Prevention of infection is the optimum for MG control, because there is no way to reliably eliminate MG from

infected fl ocks. To maintain fl ocks free of MG, three conditions must be met: replacement stock must originate from an MG-free source, biosecurity must be excellent, and the fl ocks must be regularly monitored for infection by approved testing methods (1).

Since MG is transmitted through the egg, the par-ent fl ocks must be free of MG infection if negative offspring are to be raised. Most breeding companies have eliminated MG from primary breeding stock (1). Prevention of infection at the multiplier level may be less stringent, however. In the United States, most inte-grators opt to cull breeder fl ocks that become infected with MG. Retaining infected fl ocks will likely result in established MG infection on the farm, and will also create a biosecurity risk for other farms in the area.

Biosecurity measures are essential to prevent the introduction of MG onto clean premises, as well as the spread of MG from infected premises. The risks, as well as the consequences of disease introduction due to biosecurity breaches are increasing as poultry produc-tion becomes more concentrated and farms increase in size, necessitating greater attention to biosecurity than ever before. In designing biosecurity programs it is important to note that, while MG is not a particularly hardy organism, it is able to survive for several days in the environment (2).

Regular testing of MG-clean fl ocks by sensitive tests is important to enable early detection of disease and containment of infection. In the United States, the National Poultry Improvement Plan (NPIP) (3) coordi-nates national programs for the monitoring and con-trol of MG in chicken and turkey breeding fl ocks and hatcheries. The plan requires that participant fl ocks be regularly tested by serology and culture or PCR, using approved methods.

Notes from the CEO

for more information:

avianinsight (+1) 207-873 3989 (+1) 800-655 1342 www.lahinternational.com

Dave Zacek

Group Vice President, Lohmann Solutions

Volume 3, 2012

inside

To maintain fl ocks free of MG, three conditions must be met: replacement stock must originate from an MG-free source, bio-security must be excellent, and the fl ocks must be regu-larly monitored for infection by approved test-ing methods.

Current approaches to MG control, p.1 Notes from the CEO, p.4

Natalie K. Armour, BVSc, MAM, DACPV

Naola Ferguson-Noel, PhD, MAM, DVM

0496LAH-USA_AvianInsight_Vol3-2012.indd 10496LAH-USA_AvianInsight_Vol3-2012.indd 1 10/22/12 2:49 PM10/22/12 2:49 PM

Control by medication

The primary goal of medication is to reduce clinical signs, lesions, egg production drops and transmission of MG from infected birds (1). Antibiotic medication cannot be relied upon to eliminate MG from an infected fl ock. In addition, considering the risk of antibiotic resistance development with continued use, as well as the widespread pressure to reduce the use of antibiotics in food-producing animals, antibiotic medication should not be seen as a long-term solution to MG control.

Since Mycoplasmas lack a cell wall, they are resistant to antibiotics which inhibit cell wall synthesis, such as penicillin (4). They are, however, generally sensitive to macrolides, tetracyclines, fl uoroquinolones and some other antibiotics. In the United States, fl uoro-quinolones and tilmicosin are not approved for use in poultry, and macrolides and tetra-cyclines are most commonly used to control MG infections (1).

Control by vaccination

MG vaccines are used to provide protection against respiratory disease, egg production drops and egg transmission, and, in some cases, to displace virulent field strains with attenuated vaccine strains (5). Live vaccines, as well as inactivated oil-emulsion bacterins and a fowlpox-MG recombinant vaccine are available for MG control.

Bacterins. Bacterins have been shown to be effective at protecting against egg production losses and egg transmission, and, in some cases, at reducing respiratory disease and airsacculitis associated with MG infection, although results have not been consistent (1, 5). Bacterins are generally less effective than live vaccines at preventing colonization of the respiratory tract by field strains. The advantage of bacterins is that they allow immunization without the risk of introducing live MG organisms (1, 5). In some countries, MG bacterins are used together with live vaccines in attempts to improve MG control, although this practice is not common in the United States.

Live vaccines. Three live MG vaccines are cur-rently licensed for use in the United States, and are widely used internationally: F strain (Poulvac® Myco F, Pfizer and AviPro® MG F,

Lohmann Animal Health); 6/85 (Mycovac-L®, Merck Animal Health); and TS-11 (MG TS-11, Merial (USA) and Vaxsafe®MG, Bioproperties, Ltd.). These vaccines differ in terms of their immunogenicity and virulence; character-istics which appear to be inversely related for MG (5-7). Although there are antigenic differences between different MG strains, there is no evidence that these differences infl uence the protection afforded by the cur-rently available vaccines (5).

F strain-derived vaccines have been used extensively, and have demonstrated efficacy in the prevention of respiratory signs, airsac-culitis, egg production drops and egg trans-mission of MG (1, 5). F strain persists in the upper respiratory tract for the life of the fl ock, and is capable of displacing virulent field MG strains from infected fl ocks (4). While F strain vaccines are relatively mild in chickens, they are pathogenic in turkeys (4). F strain can be transmitted through the egg, and lateral transmission has also been reported (1, 4, 8). In the United States, there has recently been a trend towards increased usage of F strain vaccines on multiple-age laying sites experi-encing significant MG challenge.

TS-11 and 6/85 represent milder vaccination approaches to MG control. Both vaccines have demonstrated efficacy at the preven-tion of MG-associated respiratory disease and egg production drops (5). They elicit little to no post-vaccination reactions, are poorly transmissible, and do not negatively affect egg production (1, 7). After vaccination, TS-11 persists for life in the upper respiratory tract, while the persistence of 6/85 is limited (4). In comparison with TS-11 and 6/85, F strain provided greater protection against airsac lesions and respiratory colonization by the challenge strain (7). In another trial, F strain, but not TS-11 or 6/85, displaced a virulent MG field strain from infected birds (9). TS-11, however, was reported to displace F strain in a program which resulted in the eradication of MG from an affected farm (10).

Recombinant vaccines. A recombinant MG vaccine, comprised of a fowlpox virus vector expressing MG antigens (Vectormune® FP-MG, Ceva Biomune) has been recently intro-duced. Like bacterins, recombinant fowlpox-MG (rFP-MG) vaccines do not introduce live

MG organisms into vaccinated fl ocks, and are thus considered a safe alternative to live vaccines. The rFP-MG vaccine does not elicit a serological response, allowing differentiation of vaccinated and infected fl ocks. There are currently no published reports demonstrat-ing the ability of this vaccine to protect against virulent MG challenge.

Current studies with commercial F strain

vaccines

Recently, the efficacy of a commercial Fstrain vaccine was compared with that of a bacterin and a rFP-MG vaccine in laying hens in the face of virulent MG R strain challenge (11). In addition to scoring air sac lesions and tracheal mucosal thickness, ovaries were examined for evidence of regression, and scored as “normal” (Fig. 1), “regressed” (Fig. 2) or “immature”. Both the F strain and the bacterin effectively protected the respiratory and reproductive tracts against challenge, when compared with the non-vaccinated controls and the rFP-MG vaccinated group.

Protection was evidenced by significant re-ductions in air sac lesion scores (Fig. 3), ovar-ian regression (Fig. 4) and tracheal mucosal thickness (Fig. 5) in the F strain and bacterin vaccinated groups. Air sac lesion scores and tracheal mucosal thickness measurements

were numerically lower in the F strain group compared with the bacterin group after chal-lenge, although these differences were not statistically significant.

In other recently published work, Evans et al. (12) evaluated the ability of different dilu-tions of two commercially available F strain vaccines and a high passage laboratory-derived F strain to elicit seroconversion, and to protect commercial layers from R strain challenge. A positive correlation between the rate of seroconversion (assessed by serum plate agglutination) and the dosage level of vaccine was observed, supporting previous findings by this group (13). For all F strain derivatives, 100% of the birds in the 1x dose and 10-1x dose vaccinated groups were positive by serology and PCR at 6 weeks post vaccination (wk p.v.). Vaccination efficacy was assessed by protection against the development of airsacculitis lesions after R strain challenge at 7 wk p.v. One hundred percent of birds vaccinated with each of the F strain derivatives were protected at the 1x and 10-1x vaccine dosages, with reduced protection evidenced by airsacculitis lesions at lower dosages.

References

1. Kleven, S.H. Control of avian mycoplasma infections in commercial poultry. Avian dis-eases 52:367-374. 2008.

2. Christensen, N.H., C.A. Yavari, A.J. McBain, and J.M. Bradbury. Investigations into the survival of Mycoplasma gallisepticum, Myco-plasma synoviae and Mycoplasma iowae on materials found in the poultry house environ-ment. Avian pathology : journal of the W.V.P.A 23:127-143. 1994.

3. Anonymous. National Poultry Improve-ment Plan and Auxiliary Provisions. In. U.S.D.o.A.A.a.P.H.I. Service, ed., Washington, DC. 2009.

4. Ley, D.H. Mycoplasma gallisepticum infec-tion. In: Diseases of Poultry 12th ed. J.R. Glisson, Y. M. Saif, A. M. Fadly, L. R. McDougald, L. K. Nolan, and D. E. Swayne, ed. Blackwell Publishing, Ames, IA. pp 807-834. 2008.

5. Whithear, K.G. Control of avian mycoplas-moses by vaccination. Rev Sci Tech 15:1527-1553. 1996.

6. Lin, M.Y., and S.H. Kleven. Evaluation of attenuated strains of Mycoplasma gallisep-ticum as vaccines in young chickens. Avian diseases 28:88-99. 1984.

7. Abd-el-Motelib, T.Y., and S.H. Kleven A com-parative study of Mycoplasma gallisepticum vaccines in young chickens. Avian diseases 37:981-987. 1993.

8. Gharaibeh, S., V. Laibinis, R. Wooten, L. Stabler, and N. Ferguson-Noel Molecular characterization of Mycoplasma gallisep-ticum isolates from Jordan. Avian diseases 55:212-216. 2011.

9. Kleven, S.H., H.H. Fan, and K.S. Turner Pen trial studies on the use of live vaccines to displace virulent Mycoplasma gallisepticum in chickens. Avian diseases 42:300-306. 1998.

10. Turner, K.S., and S.H. Kleven Eradication of live F strain mycoplasma gallisepticum vaccine using live ts-11 on a multiage com-mercial layer farm. Avian diseases 42:404-407. 1998.

11. Ferguson-Noel, N., K. Cookson, V.A. Laibinis, and S.H. Kleven The efficacy of three com-mercial Mycoplasma gallisepticum vaccines in laying hens. Avian diseases 56:272-275. 2012.

12. Evans, J.D., S.A. Leigh, J.L. Purswell, R. Jacob, E.D. Peebles, S.D. Collier, and S.L. Branton A comparative study of live attenuated F strain-derived Mycoplasma gallisepticum vaccines. Avian diseases 56:396-401. 2012.

13. Purswell, J.L., J.D. Evans, and S.L. Branton Serologic response of roosters to gradient dosage levels of a commercially available live F strain-derived Mycoplasma gallisepticum vaccine over time. Avian diseases 55:490-494. 2011.

Acknowledgement

We are grateful to Dr. Stephen Collett for theconcept that biosecurity measures reduce both the risks and the consequences of dis-ease introduction.

Figure 1. Normal ovarian follicles of a mature

egg-laying hen

Figure 2. Ovarian regression

Figure 3. Air sac lesion scores (scale 0 to 4)

following R strain challenge

Figure 4. Ovarian regression (%) following

R strain challenge

Figure 5. Tracheal mucosal thickness (μm)

following R strain challenge

0496LAH-USA_AvianInsight_Vol3-2012.indd 20496LAH-USA_AvianInsight_Vol3-2012.indd 2 10/22/12 2:49 PM10/22/12 2:49 PM

Control by medication

The primary goal of medication is to reduce clinical signs, lesions, egg production drops and transmission of MG from infected birds (1). Antibiotic medication cannot be relied upon to eliminate MG from an infected fl ock. In addition, considering the risk of antibiotic resistance development with continued use, as well as the widespread pressure to reduce the use of antibiotics in food-producing animals, antibiotic medication should not be seen as a long-term solution to MG control.

Since Mycoplasmas lack a cell wall, they are resistant to antibiotics which inhibit cell wall synthesis, such as penicillin (4). They are, however, generally sensitive to macrolides, tetracyclines, fl uoroquinolones and some other antibiotics. In the United States, fl uoro-quinolones and tilmicosin are not approved for use in poultry, and macrolides and tetra-cyclines are most commonly used to control MG infections (1).

Control by vaccination

MG vaccines are used to provide protection against respiratory disease, egg production drops and egg transmission, and, in some cases, to displace virulent field strains with attenuated vaccine strains (5). Live vaccines, as well as inactivated oil-emulsion bacterins and a fowlpox-MG recombinant vaccine are available for MG control.

Bacterins. Bacterins have been shown to be effective at protecting against egg production losses and egg transmission, and, in some cases, at reducing respiratory disease and airsacculitis associated with MG infection, although results have not been consistent (1, 5). Bacterins are generally less effective than live vaccines at preventing colonization of the respiratory tract by field strains. The advantage of bacterins is that they allow immunization without the risk of introducing live MG organisms (1, 5). In some countries, MG bacterins are used together with live vaccines in attempts to improve MG control, although this practice is not common in the United States.

Live vaccines. Three live MG vaccines are cur-rently licensed for use in the United States, and are widely used internationally: F strain (Poulvac® Myco F, Pfizer and AviPro® MG F,

Lohmann Animal Health); 6/85 (Mycovac-L®, Merck Animal Health); and TS-11 (MG TS-11, Merial (USA) and Vaxsafe®MG, Bioproperties, Ltd.). These vaccines differ in terms of their immunogenicity and virulence; character-istics which appear to be inversely related for MG (5-7). Although there are antigenic differences between different MG strains, there is no evidence that these differences infl uence the protection afforded by the cur-rently available vaccines (5).

F strain-derived vaccines have been used extensively, and have demonstrated efficacy in the prevention of respiratory signs, airsac-culitis, egg production drops and egg trans-mission of MG (1, 5). F strain persists in the upper respiratory tract for the life of the fl ock, and is capable of displacing virulent field MG strains from infected fl ocks (4). While F strain vaccines are relatively mild in chickens, they are pathogenic in turkeys (4). F strain can be transmitted through the egg, and lateral transmission has also been reported (1, 4, 8). In the United States, there has recently been a trend towards increased usage of F strain vaccines on multiple-age laying sites experi-encing significant MG challenge.

TS-11 and 6/85 represent milder vaccination approaches to MG control. Both vaccines have demonstrated efficacy at the preven-tion of MG-associated respiratory disease and egg production drops (5). They elicit little to no post-vaccination reactions, are poorly transmissible, and do not negatively affect egg production (1, 7). After vaccination, TS-11 persists for life in the upper respiratory tract, while the persistence of 6/85 is limited (4). In comparison with TS-11 and 6/85, F strain provided greater protection against airsac lesions and respiratory colonization by the challenge strain (7). In another trial, F strain, but not TS-11 or 6/85, displaced a virulent MG field strain from infected birds (9). TS-11, however, was reported to displace F strain in a program which resulted in the eradication of MG from an affected farm (10).

Recombinant vaccines. A recombinant MG vaccine, comprised of a fowlpox virus vector expressing MG antigens (Vectormune® FP-MG, Ceva Biomune) has been recently intro-duced. Like bacterins, recombinant fowlpox-MG (rFP-MG) vaccines do not introduce live

MG organisms into vaccinated fl ocks, and are thus considered a safe alternative to live vaccines. The rFP-MG vaccine does not elicit a serological response, allowing differentiation of vaccinated and infected fl ocks. There are currently no published reports demonstrat-ing the ability of this vaccine to protect against virulent MG challenge.

Current studies with commercial F strain

vaccines

Recently, the efficacy of a commercial Fstrain vaccine was compared with that of a bacterin and a rFP-MG vaccine in laying hens in the face of virulent MG R strain challenge (11). In addition to scoring air sac lesions and tracheal mucosal thickness, ovaries were examined for evidence of regression, and scored as “normal” (Fig. 1), “regressed” (Fig. 2) or “immature”. Both the F strain and the bacterin effectively protected the respiratory and reproductive tracts against challenge, when compared with the non-vaccinated controls and the rFP-MG vaccinated group.

Protection was evidenced by significant re-ductions in air sac lesion scores (Fig. 3), ovar-ian regression (Fig. 4) and tracheal mucosal thickness (Fig. 5) in the F strain and bacterin vaccinated groups. Air sac lesion scores and tracheal mucosal thickness measurements

were numerically lower in the F strain group compared with the bacterin group after chal-lenge, although these differences were not statistically significant.

In other recently published work, Evans et al. (12) evaluated the ability of different dilu-tions of two commercially available F strain vaccines and a high passage laboratory-derived F strain to elicit seroconversion, and to protect commercial layers from R strain challenge. A positive correlation between the rate of seroconversion (assessed by serum plate agglutination) and the dosage level of vaccine was observed, supporting previous findings by this group (13). For all F strain derivatives, 100% of the birds in the 1x dose and 10-1x dose vaccinated groups were positive by serology and PCR at 6 weeks post vaccination (wk p.v.). Vaccination efficacy was assessed by protection against the development of airsacculitis lesions after R strain challenge at 7 wk p.v. One hundred percent of birds vaccinated with each of the F strain derivatives were protected at the 1x and 10-1x vaccine dosages, with reduced protection evidenced by airsacculitis lesions at lower dosages.

References

1. Kleven, S.H. Control of avian mycoplasma infections in commercial poultry. Avian dis-eases 52:367-374. 2008.

2. Christensen, N.H., C.A. Yavari, A.J. McBain, and J.M. Bradbury. Investigations into the survival of Mycoplasma gallisepticum, Myco-plasma synoviae and Mycoplasma iowae on materials found in the poultry house environ-ment. Avian pathology : journal of the W.V.P.A 23:127-143. 1994.

3. Anonymous. National Poultry Improve-ment Plan and Auxiliary Provisions. In. U.S.D.o.A.A.a.P.H.I. Service, ed., Washington, DC. 2009.

4. Ley, D.H. Mycoplasma gallisepticum infec-tion. In: Diseases of Poultry 12th ed. J.R. Glisson, Y. M. Saif, A. M. Fadly, L. R. McDougald, L. K. Nolan, and D. E. Swayne, ed. Blackwell Publishing, Ames, IA. pp 807-834. 2008.

5. Whithear, K.G. Control of avian mycoplas-moses by vaccination. Rev Sci Tech 15:1527-1553. 1996.

6. Lin, M.Y., and S.H. Kleven. Evaluation of attenuated strains of Mycoplasma gallisep-ticum as vaccines in young chickens. Avian diseases 28:88-99. 1984.

7. Abd-el-Motelib, T.Y., and S.H. Kleven A com-parative study of Mycoplasma gallisepticum vaccines in young chickens. Avian diseases 37:981-987. 1993.

8. Gharaibeh, S., V. Laibinis, R. Wooten, L. Stabler, and N. Ferguson-Noel Molecular characterization of Mycoplasma gallisep-ticum isolates from Jordan. Avian diseases 55:212-216. 2011.

9. Kleven, S.H., H.H. Fan, and K.S. Turner Pen trial studies on the use of live vaccines to displace virulent Mycoplasma gallisepticum in chickens. Avian diseases 42:300-306. 1998.

10. Turner, K.S., and S.H. Kleven Eradication of live F strain mycoplasma gallisepticum vaccine using live ts-11 on a multiage com-mercial layer farm. Avian diseases 42:404-407. 1998.

11. Ferguson-Noel, N., K. Cookson, V.A. Laibinis, and S.H. Kleven The efficacy of three com-mercial Mycoplasma gallisepticum vaccines in laying hens. Avian diseases 56:272-275. 2012.

12. Evans, J.D., S.A. Leigh, J.L. Purswell, R. Jacob, E.D. Peebles, S.D. Collier, and S.L. Branton A comparative study of live attenuated F strain-derived Mycoplasma gallisepticum vaccines. Avian diseases 56:396-401. 2012.

13. Purswell, J.L., J.D. Evans, and S.L. Branton Serologic response of roosters to gradient dosage levels of a commercially available live F strain-derived Mycoplasma gallisepticum vaccine over time. Avian diseases 55:490-494. 2011.

Acknowledgement

We are grateful to Dr. Stephen Collett for theconcept that biosecurity measures reduce both the risks and the consequences of dis-ease introduction.

Figure 1. Normal ovarian follicles of a mature

egg-laying hen

Figure 2. Ovarian regression

Figure 3. Air sac lesion scores (scale 0 to 4)

following R strain challenge

Figure 4. Ovarian regression (%) following

R strain challenge

Figure 5. Tracheal mucosal thickness (μm)

following R strain challenge

0496LAH-USA_AvianInsight_Vol3-2012.indd 20496LAH-USA_AvianInsight_Vol3-2012.indd 2 10/22/12 2:49 PM10/22/12 2:49 PM

At Lohmann Animal Health International, we take pride in our role as a practical technical partner with poultry producers. This objective has been in place in our company since our Winslow, Maine operation was founded in 1957. Many new disease challenges have emerged and been subsequently brought under control during the past 55 years. During that time, we have been doing our part to help poultry producers prevent the damages caused by those infections.

We pioneered the category of inactivated poultry vaccines and still lead the industry in adjuvant technology. We pioneered inactivated Newcastle vaccine, live infectious Laryngotracheitis vaccine, the first two live Salmonella vaccines and others. We currently have a significant amount of our resources committed to R&D aimed at further advances in disease prevention for the poultry producer.

Mycoplasma gallisepticum and the damage it causes from poor feed

conversion, lower egg production rate, decreased egg quality, increased mortality and morbidity is the subject of our paper for this issue of Avian Insight.

To help chickens continue to produce profitably in the face of this largely eradicated disease, we provide AviPro® 104 MG Bacterin, AviPro® 304 ND-IB-MG and AviPro® MG F live vaccines. In addition, our Technical Service Veterinarians are available to help you program the timing and product for your operation. We at Lohmann Animal Health will team with you to minimize the damages caused by Mycoplasma

gallisepticum. Contact your Lohmann Animal Health representative and learn how we can help you prevent damages from MG and other infectious agents.

Personal note: This will be my last commentary for Avian Insight. I am

moving on to begin a new enterprise within the Lohmann SE Group

called Lohmann Solutions. It is a global consultancy with centers

located around the world, created to support our customers regarding

issues related to production of safe, healthy and sustainable food, such

as prevention of foodborne zoonoses, animal welfare support and

water quality programs. The Vice President and Director of Sales for

the Americas of Lohmann Animal Health International, Inc., Shannon

Kellner will take on the Avian Insight commentary responsibility

beginning with the next issue.

avianinsightA L O H M A N N A N I M A L H E A L T H N E W S B R I E F

Current approaches to MG control

Introduction

Mycoplasma gallisepticum (MG) is one of the lead-ing causes of economic loss to the poultry industry worldwide. The disease affects primarily chickens and turkeys, causing respiratory infections and airsacculitis, as well as egg production drops. The global expansion of the commercial poultry industry has resulted in greater concentrations of susceptible birds in poultry-producing areas, increasing the risk and consequences of MG infection. In the United States, most broiler and turkey production is MG negative. MG prevalence in commercial laying operations, however, is considerably higher, particularly on large multiple-age complexes.

There are three general approaches to MG control: Prevention of infection is ideal, but in situations where this is not considered feasible (eg. multiple-age com-plexes), medication and/or vaccination are options. In this article, we discuss approaches to MG control, fo-cusing on the current situation in the United States. We also review recent findings related to the performance of F strain vaccines.

Control by prevention of infection

Prevention of infection is the optimum for MG control, because there is no way to reliably eliminate MG from

infected fl ocks. To maintain fl ocks free of MG, three conditions must be met: replacement stock must originate from an MG-free source, biosecurity must be excellent, and the fl ocks must be regularly monitored for infection by approved testing methods (1).

Since MG is transmitted through the egg, the par-ent fl ocks must be free of MG infection if negative offspring are to be raised. Most breeding companies have eliminated MG from primary breeding stock (1). Prevention of infection at the multiplier level may be less stringent, however. In the United States, most inte-grators opt to cull breeder fl ocks that become infected with MG. Retaining infected fl ocks will likely result in established MG infection on the farm, and will also create a biosecurity risk for other farms in the area.

Biosecurity measures are essential to prevent the introduction of MG onto clean premises, as well as the spread of MG from infected premises. The risks, as well as the consequences of disease introduction due to biosecurity breaches are increasing as poultry produc-tion becomes more concentrated and farms increase in size, necessitating greater attention to biosecurity than ever before. In designing biosecurity programs it is important to note that, while MG is not a particularly hardy organism, it is able to survive for several days in the environment (2).

Regular testing of MG-clean fl ocks by sensitive tests is important to enable early detection of disease and containment of infection. In the United States, the National Poultry Improvement Plan (NPIP) (3) coordi-nates national programs for the monitoring and con-trol of MG in chicken and turkey breeding fl ocks and hatcheries. The plan requires that participant fl ocks be regularly tested by serology and culture or PCR, using approved methods.

Notes from the CEO

for more information:

avianinsight (+1) 207-873 3989 (+1) 800-655 1342 www.lahinternational.com

Dave Zacek

Group Vice President, Lohmann Solutions

Volume 3, 2012

inside

To maintain fl ocks free of MG, three conditions must be met: replacement stock must originate from an MG-free source, bio-security must be excellent, and the fl ocks must be regu-larly monitored for infection by approved test-ing methods.

Current approaches to MG control, p.1 Notes from the CEO, p.4

Natalie K. Armour, BVSc, MAM, DACPV

Naola Ferguson-Noel, PhD, MAM, DVM

0496LAH-USA_AvianInsight_Vol3-2012.indd 10496LAH-USA_AvianInsight_Vol3-2012.indd 1 10/22/12 2:49 PM10/22/12 2:49 PM