Mycoplasma hyopneumoniae
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197771093
2008-03-12T18:30:25Z
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{{Taxobox
| color = lightgrey
| name = ''Mycoplasma hyopneumonaie''
| regnum = Bacteria
| divisio = Firmicutes
| classis = Mollicutes
| ordo = Mycoplasmatales
| familia = Mycoplasmataceae
| genus = ''[[Mycoplasma]]''
| species = '''''M. hyopneumoniae'''''
| binomial = ''Mycoplasma hyopneumoniae''
| binomial_authority = Maré and Switzer, 1965
}}
'''''Mycoplasma hyopneumoniae''''' is a species of [[bacteria]] known to cause the disease Porcine Enzootic Pneumonia, a highly contagious and chronic disease affecting pigs (Whittlestone, 1979). As with other [[mollicutes]], ''M. hyopneumoniae'' is small in size (400 - 1200nm), has a small [[genome]] (893 - 920 kilo-base pairs (kb)) and lacks a [[cell wall]] (Tajima ''et al'', 1982). It is considered to be difficult to grow in laboratories due to its complex nutritional requirements.
This [[bacterium]] is a concern in the livestock industry as it causes a significant reduction in the growing weight of pigs. Losses in the [[U.S.A.]] have been previously estimated at 200 million to 1 billion dollars per annum (Clark ''et al'', 1991). Porcine enzootic pneumonia is spread worldwide and ''M. hyopneumoniae'' is present in almost every pig herd (Minion, 2002). Treatment of this disease is limited to [[antibiotics]], which are currently ineffective as they do not completely remove the infection. [[Vaccines]] have been found to reduce the severity of the disease but do not prevent the disease from occurring in infected pigs (Haesebrouck, ''et al'', 2004).
''M. hyopneumoniae'' has been found to attach to the [[cilia]] of [[epithelial cells]] in the lungs of swine. They cause [[cilia]] to stop beating (ciliostasis), loss of [[cilia]] and eventually [[epithelial cell]] death; which is the source of the [[lesions]] found in pigs with porcine enzootic pneumonia. Sadly, the [[immune response]] caused by the presence of ''M. hyopneumoniae'' in pigs is slow and ineffective (Minion, 2002); it is also believed to cause much of the damage that is seen in pigs with the disease. This [[mycoplasma]] is not known to produce any specifically harmful [[toxin]] like many other disease-causing [[bacteria]], but some mildly toxic by-products have been observed (Geary ''et al'', 1985).
''Mycoplasma hyopneumoniae'' has been a topic of interest in the scientific community due to the economic impact of porcine enzootic pneumonia. Three separate [[strain (biology)|strains]] (232, J & 7448) of this [[mycoplasma]] have had their [[genomes]] [[sequenced]], making it the most [[sequenced]] [[mycoplasma]] (Minion ''et al'', 2004; Vasconcelos ''et al'', 2005). Research has been mainly focused on identifying [[adhesin]]s with a final goal of developing an effective [[vaccine]] that prevents ''M. hyopneumoniae'' from attaching to lung [[cilia]].
==References==
*Clark, L. K., C. H. Armstrong, M. J. Freeman, A. B. Scheidt, L. Sands-Freeman, and K. Knox. 1991. Investigating the transmission of Mycoplasma hyopneumoniae in a swine herd with enzootic pneumonia. ''Veterinary Medicine'' '''86''':543-550.
*Geary, S. J., and E. M. Walczak. 1985. Isolation of a Cytopathic Factor from Mycoplasma-Hyopneumoniae. ''Infection and Immunity'' '''48''':576-578.
*Haesebrouck, F., F. Pasmans, K. Chiers, D. Maes, R. Ducatelle, and A. Decostere. 2004. Efficacy of vaccines against bacterial diseases in swine: what can we expect? ''Vet Microbiol'' '''100''':255-68.
*Maré, C. J. and W. P. Switzer 1965. ''Vet Med Small Anim Clin'' '''60''':841-846
*Minion, F. C. 2002. Molecular pathogenesis of mycoplasma animal respiratory pathogens. ''Frontiers in Bioscience'' '''7''':d1410-1422.
*Minion, F. C., E. J. Lefkowitz, M. L. Madsen, B. J. Cleary, S. M. Swartzell, and G. G. Mahairas. 2004. The genome sequence of Mycoplasma hyopneumoniae strain 232, the agent of swine mycoplasmosis. ''J Bacteriol'' '''186''':7123-33.
*Tajima, M., and T. Yagihashi. 1982. Interaction of Mycoplasma-Hyopneumoniae with the Porcine Respiratory Epithelium as Observed by Electron-Microscopy. ''Infection and Immunity'' '''37''':1162-1169.
*Vasconcelos, A. T., H. B. Ferreira, C. V. Bizarro, S. L. Bonatto, M. O. Carvalho, P. M. Pinto, D. F. Almeida, L. G. Almeida, R. Almeida, L. Alves-Filho, E. N. Assuncao, V. A. Azevedo, M. R. Bogo, M. M. Brigido, M. Brocchi, H. A. Burity, A. A. Camargo, S. S. Camargo, M. S. Carepo, D. M. Carraro, J. C. de Mattos Cascardo, L. A. Castro, G. Cavalcanti, G. Chemale, R. G. Collevatti, C. W. Cunha, B. Dallagiovanna, B. P. Dambros, O. A. Dellagostin, C. Falcao, F. Fantinatti-Garboggini, M. S. Felipe, L. Fiorentin, G. R. Franco, N. S. Freitas, D. Frias, T. B. Grangeiro, E. C. Grisard, C. T. Guimaraes, M. Hungria, S. N. Jardim, M. A. Krieger, J. P. Laurino, L. F. Lima, M. I. Lopes, E. L. Loreto, H. M. Madeira, G. P. Manfio, A. Q. Maranhao, C. T. Martinkovics, S. R. Medeiros, M. A. Moreira, M. Neiva, C. E. Ramalho-Neto, M. F. Nicolas, S. C. Oliveira, R. F. Paixao, F. O. Pedrosa, S. D. Pena, M. Pereira, L. Pereira-Ferrari, I. Piffer, L. S. Pinto, D. P. Potrich, A. C. Salim, F. R. Santos, R. Schmitt, M. P. Schneider, A. Schrank, I. S. Schrank, A. F. Schuck, H. N. Seuanez, D. W. Silva, R. Silva, S. C. Silva, C. M. Soares, K. R. Souza, R. C. Souza, C. C. Staats, M. B. Steffens, S. M. Teixeira, T. P. Urmenyi, M. H. Vainstein, L. W. Zuccherato, A. J. Simpson, and A. Zaha. 2005. Swine and poultry pathogens: the complete genome sequences of two strains of Mycoplasma hyopneumoniae and a strain of Mycoplasma synoviae. ''J Bacteriol'' '''187''':5568-77.
*Whittlestone, P. 1979. Porcine Mycoplasmas, p. 133-166. In J. G. Tully and R. F. Whitcomb (ed.), ''The Mycoplasmas, vol. II''. Academic Press, Inc., New York.
[[Category:Mollicutes]]
[[Category:Swine diseases]]
[[fi:Porsasyskä]]