RESUMEN
Bovine diseases due to Mycoplasma bovis can cause considerable economic losses in cattle production. While the pathogen is principally responsible for therapy-resistant mastitis on large dairy farms, on smaller farms the typical mycoplasma diseases are calf pneumonia and arthritis. Moreover, the pathogen is able to cause genital disorders. M. bovis infection can be controlled effectively only if appropriate measures are implemented at the earliest possible stage. Since immunoprophylaxis and antibiotic treatment are known to be ineffective, control measures must include the introduction of strict hygiene standards, the restriction of animal movement out of infected herds and the culling of clinically diseased animals and shedders of the mycoplasma (the latter only in the case of mastitis and genital disorders). In this review, symptoms of the various diseases caused by M. bovis are described and characteristics of the course of infection are outlined. To clarify the origin and spread of the infection, the authors describe the main properties and reservoirs of the pathogen and summarise experimental evidence on modes of transmission to susceptible organs. As effective diagnosis is a prerequisite for the introduction of early control measures, the advantages and disadvantages of currently used diagnostic methods are discussed in detail. It is a serious shortcoming if testing for mycoplasmas is not included in routine bacterial examination of clinical samples. As a consequence, some M. bovis infections will remain undetected and outbreaks cannot be controlled properly. Finally, practical recommendations are given for prevention and control, including the formation of mycoplasma-free herds.
Asunto(s)
Artritis Infecciosa/veterinaria , Enfermedades de los Bovinos/microbiología , Enfermedades de los Genitales Femeninos/veterinaria , Enfermedades de los Genitales Masculinos/veterinaria , Mastitis Bovina/microbiología , Mycoplasma/fisiología , Neumonía por Mycoplasma/veterinaria , Animales , Artritis Infecciosa/microbiología , Bovinos , Enfermedades de los Bovinos/diagnóstico , Enfermedades de los Bovinos/prevención & control , Femenino , Enfermedades de los Genitales Femeninos/microbiología , Enfermedades de los Genitales Masculinos/microbiología , Masculino , Mastitis Bovina/diagnóstico , Mastitis Bovina/prevención & control , Neumonía por Mycoplasma/microbiologíaRESUMEN
Mycoplasma (M.) bovis cytadhesion was studied using permanent embryonic bovine lung (EBL) cells as host system. Adherence rates were found to be strongly dependent on temperature and the mycoplasma-to-EBL ratio near the point of saturation of the attachment isotherm was determined to be 225 : 1. Mild trypsinization of viable M. bovis cells caused a measurable decrease of adherence indicating that surface proteins, among them the P26 antigen, played a major part as adhesion factors. Neuraminidase treatment of mycoplasmas led to a drastic reduction of adherence rates, which emphasizes the importance of sialyl moieties in adhesive interactions. The ability of the P26 antigen, a hydrophilic 32-kDa protein, to function as an adhesin was confirmed using a competitive adherence assay, in which the HPLC-purified protein was shown to reduce mycoplasma adhesion. These data complement previous findings obtained with the corresponding monoclonal antibody (MAb) 4F6. In further inhibition experiments, it could be demonstrated that MAb 1E5, which is directed against a common epitope of at least three members of the Vsp (variable surface protein) family of M. bovis, was also capable of decreasing mycoplasma attachment to EBL cells. This is the first evidence of possible involvement of Vsps in cytadhesion. In an effort to identify more putative adhesion proteins of this organism, the reverse adherence screening assay was used, a procedure based on the specific binding of labelled mammalian tissue culture cells to Western-blotted mycoplasmal proteins.
Asunto(s)
Adhesión Bacteriana , Mycoplasma/metabolismo , Adhesinas Bacterianas/metabolismo , Antígenos de Superficie/metabolismo , Línea Celular , Neuraminidasa/metabolismo , Temperatura , Tripsina/metabolismoRESUMEN
Two methods are suggested that allow direct detection of Mycoplasma bovis from clinical samples, i.e. milk and nasal swabs, respectively. Milk samples were trypsinized in the presence of Triton X-100 and passed through a DNA-binding filter membrane, from which DNA was extracted and subjected to PCR. The detection limit was 500 cfu ml-1 on agarose gels and 50 cfu ml-1 after Southern hybridization so that the method can be used to monitor low-titre samples from animals at the subclinical stage. Results became available within 24 h, thus rendering the procedure more rapid than ELISA and culture techniques. Six other methods designed for milk or other complex samples were tested in this study, but found unsatisfactory. Rapid and specific detection of the pathogen by PCR from nasal mucus treated with lysis buffer and proteinase K was demonstrated for swabs taken from experimentally infected calves. Both methods represent useful tools for effective livestock monitoring and single-animal diagnosis.
Asunto(s)
Leche/microbiología , Mycoplasma/aislamiento & purificación , Mucosa Nasal/microbiología , Reacción en Cadena de la Polimerasa/métodos , Animales , Secuencia de Bases , Bovinos , Cartilla de ADN , ADN Bacteriano/análisis , Datos de Secuencia MolecularRESUMEN
Rapid and specific detection of organisms belonging to the Mycoplasma mycoides cluster, among them Mycoplasma (M.) mycoides subsp. mycoides SC, the agent of contagious bovine pleuropneumonia, is an important condition for effective control of the respective animal diseases. In an effort to improve diagnosis, a PCR identification scheme for these mycoplasmas was developed. A set of primer combinations derived from the CAP-21 genomic regions of member organisms of the Mycoplasma mycoides cluster was selected by means of which complete differentiation within the cluster can be accomplished. Nested PCR involving cluster-specific amplification at the first stage and group-specific amplification using internal primers at the second stage was shown to be applicable for identification of all six groups forming the cluster. For example, external primers P1 /P2 and internal primers P6/P7 were used to distinguish M. mycoides subsp. mycoides SC from LC strains. Using the present PCR procedure, identification of mycoplasmas could be considerably accelerated in comparison to conventional methods (5 h vs. one week) and specificity was also improved.
Asunto(s)
Enfermedades de los Bovinos , Mycoplasma mycoides/clasificación , Pleuroneumonía Contagiosa/diagnóstico , Reacción en Cadena de la Polimerasa/métodos , Animales , Bovinos , Cartilla de ADN , ADN Bacteriano/aislamiento & purificación , Cabras , Mycoplasma mycoides/genética , Mycoplasma mycoides/aislamiento & purificación , Pleuroneumonía Contagiosa/prevención & control , SerotipificaciónRESUMEN
Cardiac activity contaminates respiratory electric field plethysmography (EFPG) signals, and vice versa, and is usually treated as an artefact. On the other hand, simultaneous information on respiration and cardiac activity is often required in clinical practice. Hence, we use time-frequency spectral analysis (TFSA) by means of the spectrogram (SG) to investigate the instantaneous cardio-respiratory information contained in EFPG-signals and show that it is a practical means of extracting this information out of a single EFPG-signal. Comparisons with a Wigner distribution reveal sufficient time-frequency resolution of the SG for detection of physiological events in EFPG-signals. SG-analysis indicates spectral peaks related to respiration and cardiac activity (depending on the electrode configuration, up to the third and fifth harmonic, respectively) and the possibility to detect respiratory sinus arrhythmia by means of EFPG-measurements. Intermodulation products cause overlaps of respiratory and cardiac spectra pointing out nonlinear relationships. Additionally, SG-analysis supplies essential information for the separation of EFPG-signals into respiratory and cardiac components, by means of filter techniques.
Asunto(s)
Cardiografía de Impedancia , Procesamiento de Señales Asistido por Computador , Adolescente , Adulto , Anciano , Artefactos , Cardiografía de Impedancia/instrumentación , Niño , Preescolar , Ejercicio Físico , Análisis de Fourier , Humanos , Lactante , Persona de Mediana Edad , Contracción Miocárdica , Mecánica Respiratoria , Descanso , Procesamiento de Señales Asistido por Computador/instrumentación , SueñoRESUMEN
Electric field plethysmography (EFPG) signals of the human thorax consist of a baseline component, a respiratory component and a cardiac component. This paper investigates to what extent a two-dimensional finite-element model of the human thorax can serve as a tool for signal prediction allowing for both optimisation of electrode position and effective signal interpretation. In the model inspiration is taken into account by decreasing lung conductivity. Modelling of cardiac activity involves heart geometry changes and lung conductivity increase. Comparison with experiments shows that the model is more effective for strip than spot electrodes for current injection. Modelling results suggest that the thorax behaves approximately as a homogeneous structure with an inspiratory conductivity increase of about 5%. Two electrode pairs are preferable for monitoring respiration in general. As cardiac activity involves two counter-acting signal sources in the thorax, optimum electrode position is obtained using four separated electrodes. However, recommendable positions for two electrode pairs are on the left sternal and right parasternal line. The investigation shows that in providing a proper modelling of respiration and cardiac activity, a 2-D model provides a practical tool for modelling EFPG signals with the cost of a few structural and systematical restrictions.
Asunto(s)
Cardiografía de Impedancia/instrumentación , Simulación por Computador , Corazón/fisiología , Pulmón/fisiología , Procesamiento de Señales Asistido por Computador/instrumentación , Gráficos por Computador , Electrodos , Humanos , Reproducibilidad de los Resultados , Respiración/fisiologíaRESUMEN
Respiration monitoring by means of electric field plethysmography is influenced by cardiac activity, which represents an artefact although of physiological relevance itself. For a separation of respiration and cardiac signals, a portable plethysmograph was developed, which uses a fifth electrode in addition to the conventional tetrapolar electrode arrangement. The separation is attained by weighted software subtraction of two detected signals. In a comparative way, three mathematical methods are discussed for the effective determination of individual weighting factors. Results of the practical applications indicate the best results for a method based on Fast Fourier Transformation.
Asunto(s)
Corazón/fisiología , Monitoreo Fisiológico/métodos , Pletismografía/métodos , Respiración/fisiología , Electrodos , Análisis de Fourier , Humanos , MatemáticaRESUMEN
Cloacal swabs from adult breeding geese of both sexes from six separate farms were culturally examined for mycoplasmas. Geese from these flocks did not show any clinical signs of illness, increased mortality or drop in egg production during the reproductive season. The results revealed the presence of mycoplasmas in all the flocks tested. Mycoplasma (M.) cloacale was found in 6 flocks, M. anseris in 4 flocks, Mycoplasma species 1220 in 3 flocks and non-identifiable Mycoplasmas in 2 flocks. More than one Mycoplasma species was simultaneously isolated from 14 out of 37 geese.
Asunto(s)
Gansos/microbiología , Mycoplasma/aislamiento & purificación , Animales , Cloaca/microbiología , Femenino , Alemania , MasculinoRESUMEN
The polymerase chain reaction (PCR) has been used for the general detection of Mollicutes. 25 Mycoplasma and Acholeplasma species were detected including important contaminants of cell cultures such as M. orale, M. arginini, M. hyorhinis, M. fermentans, A. laidlawii and additional human and animal mycoplasmas. PCR reactions were performed using a set of nested primers defined from conserved regions of the 16S rRNA gene. The detection limit was determined to be 1 fg mycoplasma DNA, which is equivalent to 1-2 genome copies of the 16S rRNA coding region. The identity of the amplification products was confirmed by agarose gel electrophoresis and restriction enzyme analysis. DNA from closely and distantly related micro-organisms did not give rise to specific amplification products. The method presented here offers a much more sensitive, specific and rapid assay for the detection of mycoplasmas than the existing ones.
Asunto(s)
Mycoplasma/aislamiento & purificación , Reacción en Cadena de la Polimerasa , Secuencia de Bases , Código Genético , Datos de Secuencia Molecular , ARN Ribosómico 16S/genética , Sensibilidad y Especificidad , Factores de TiempoRESUMEN
An enzyme-linked immunosorbent assay (ELISA) using a monoclonal antibody (mAb) was developed to detect Mycoplasma (M.) bovis in milk samples from cattle. With this procedure, 1 x 10(5) colony forming units per ml (cfu/ml) milk were routinely detectable. No cross-reactions to other bovine mycoplasma species were observed. Both the sensitivity of 80.6% and the specificity of 94.9% are sufficient for its use in diagnosis of clinical mastitis. The sensitivity could be increased by 10% after introduction of 48-hour pre-incubation of samples. This allowed recognition of cows shedding M. bovis amounts of 10(3) cfu/ml in their milk, which is typical for subclinical cases. Screening of milk samples by means of this antigen capture ELISA has advantages over culture methods in terms of speed and potential to monitor large herds, thereby permitting early culling of infected animals to reduce transmission of the pathogen to non-infected animals.
Asunto(s)
Antígenos Bacterianos/análisis , Ensayo de Inmunoadsorción Enzimática/veterinaria , Mastitis Bovina/microbiología , Leche/microbiología , Infecciones por Mycoplasma/veterinaria , Mycoplasma/aislamiento & purificación , Animales , Anticuerpos Monoclonales , Bovinos , Ensayo de Inmunoadsorción Enzimática/métodos , Femenino , Infecciones por Mycoplasma/microbiología , Sensibilidad y EspecificidadRESUMEN
The attachment of Mycoplasma bovis to permanent embryonic bovine lung (EBL) cells was studied in order to identify factors participating in the adhesion process. A monoclonal antibody directed against a 26 kDa protein of M. bovis was shown to reduce cytadherence of strains 120 and 454 by 46% and 70%, respectively. In uninhibited assays, strain 120 which exhibits an intense 26 kDa band in electrophoretic protein patterns adhered more strongly to EBL cell monolayers than strain 454 whose corresponding band is considerably weaker. The findings indicate involvement of the 26 kDa protein in M. bovis adherence. In further inhibition experiments, the ability of N-acetyl-neuraminlactose, glycophorin and dextran sulfate to significantly reduce adherence could be demonstrated. This suggests participation of sialic acid residues and probably also sulfatide groups as binding receptors. The data point to a complex adhesion mechanism with similarities to M. pneumoniae.
Asunto(s)
Anticuerpos Monoclonales/inmunología , Adhesión Bacteriana , Carbohidratos/farmacología , Mastitis Bovina/microbiología , Mycoplasma/metabolismo , Animales , Anticuerpos Antibacterianos/inmunología , Adhesión Bacteriana/efectos de los fármacos , Adhesión Bacteriana/inmunología , Bovinos , Línea Celular , Sulfato de Dextran/farmacología , Dextranos/farmacología , Femenino , Glicoforinas/farmacología , Lactosa/análogos & derivados , Lactosa/farmacología , Pulmón/citología , Pulmón/embriología , Pulmón/microbiología , Mycoplasma/efectos de los fármacos , Mycoplasma/inmunología , Infecciones por Mycoplasma/microbiología , Infecciones por Mycoplasma/veterinaria , Ácidos Siálicos/farmacologíaRESUMEN
Dielectric measurements were made on lung samples with different electrode systems in the frequency range 5 kHz-100 kHz. In the case of plate electrodes and spot electrodes, the effects of electrode polarization were partly corrected. An air filling factor F is defined, which is determined from the mass and volume of the sample. The results indicate that the electrical properties of lung tissue are highly dependent on the condition of the tissue. Furthermore they show that the conductivity sigma as well as the relative permittivity epsilon r decreases with increasing F. This is discussed using histological material. Using a simple theoretical model, the decrease of sigma and epsilon r is explained by the thinning of the alveolar walls as well as by the deformation of the epithelial cells and blood vessels through the expansion of the alveoli.
Asunto(s)
Pulmón/fisiología , Enfisema Pulmonar/fisiopatología , Animales , Bovinos , Conductividad Eléctrica , Electrodos , Técnicas In VitroRESUMEN
Mycoplasma bovis, the main causative agent of mycoplasmal mastitis, arthritis and pneumonia in cattle, causes considerable economic losses. Veterinary hygiene measures would be most effective if introduced at an early stage, especially the culling of cows shedding the pathogen for the control of mastitis. It is therefore crucial to ensure that diagnostic methods are available which can perform rapid and specific detection of the agent at acceptable costs. Six different detection methods have been compared and evaluated in terms of performance parameters and suitability for routine diagnosis. Conventional M. bovis isolation and identification from culture is the only technique used for routine diagnosis at present. However, this process is rather laborious and time-consuming, and final results are available only after several days. Enzyme-linked immunosorbent assay (ELISA) techniques can be used to screen for M. bovis antibodies or antigens in clinically-diseased animals. Detection of the agent in subclinical cases was accomplished in pre-incubated samples by an antigen capture ELISA involving a monoclonal antibody. Whole-cell protein patterns generated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis were used to identify and classify field isolates. Nucleic acid hybridizations using probes of defined specificity were conducted both as filter dot blot assay and in solution with ribosomal ribonucleic acid as the target. The latter was found to be potentially suitable for the screening of biological samples, although problems due to high background and reduced specificity remained. Finally, the presence of M. bovis cells in culture supernatant and in milk samples was demonstrated using the polymerase chain reaction. This procedure is potentially superior to all others currently available, due to its high sensitivity, specificity and speed. However, a number of practical problems must be solved prior to full-scale introduction of this technique for routine diagnosis.
Asunto(s)
Enfermedades de los Bovinos/diagnóstico , Infecciones por Mycoplasma/veterinaria , Mycoplasma/aislamiento & purificación , Animales , Anticuerpos Antibacterianos/análisis , Antígenos Bacterianos/análisis , Artritis Infecciosa/diagnóstico , Artritis Infecciosa/veterinaria , Bovinos , ADN Bacteriano/análisis , Femenino , Mastitis Bovina/diagnóstico , Mycoplasma/genética , Mycoplasma/inmunología , Infecciones por Mycoplasma/diagnóstico , Neumonía por Mycoplasma/diagnóstico , Neumonía por Mycoplasma/veterinariaRESUMEN
Detection of Mycoplasma bovis by traditional culture methods is rather time-consuming and is often hampered by bacterial contamination. The development of a rapid and specific alternative is, therefore, an important prerequisite in improving the diagnosis of bovine diseases caused by this agent. The authors have successfully used nucleic acid probes containing genomic restriction fragments of M. bovis cloned into the plasmid vector pUC19 for species-specific detection by dot blot hybridisation of small quantities of M. bovis deoxyribonucleic acid (DNA). The problem of direct M. bovis detection from contaminated milk could not be solved using this procedure. Therefore, further research was conducted using in vitro DNA amplification by polymerase chain reaction (PCR). Species-specific nucleic acid probes were sequenced and suitable PCR primers selected. Using the PCR procedure, ten colony-forming units (CFU) were detected from broth cultures and, after DNA isolation, the equivalent of 1 CFU was detected. Direct detection of M. bovis from biological samples proved extremely difficult due to protein interference. It was shown, however, that direct PCR detection from milk is possible after effective protein removal by combined extraction and protease digestion.
Asunto(s)
Enfermedades de los Bovinos/diagnóstico , ADN Bacteriano/análisis , Infecciones por Mycoplasma/veterinaria , Mycoplasma/aislamiento & purificación , Animales , Secuencia de Bases , Bovinos , Cartilla de ADN/química , Sondas de ADN , ADN Bacteriano/química , Leche/microbiología , Datos de Secuencia Molecular , Mycoplasma/genética , Infecciones por Mycoplasma/diagnóstico , Hibridación de Ácido Nucleico , Reacción en Cadena de la Polimerasa , Especificidad de la EspecieRESUMEN
On a cattle farm latently infected by M. bovis, field studies aiming at the formation of a mycoplasma free herd, were carried out with a group of newborn female calves. These calves were strictly separated from their dams and any other cattle immediately after parturition. Intensive investigations for mycoplasmas were made over 30 months (mycoplasma isolation from nasal swabs, antibody detection by means of indirect hemagglutination test and ELISA technique). M. bovis could never be isolated from the samples. Also, there were no antibodies to M. bovis. In some animals antibody titers to M. bovis occurred after having contact with cattle infected with M. bovis. The results demonstrate a practicable way to establish cattle herds free from M. bovis infection.
Asunto(s)
Cruzamiento , Mastitis Bovina/prevención & control , Infecciones por Mycoplasma/veterinaria , Animales , Anticuerpos Antibacterianos/sangre , Bovinos , Femenino , Mycoplasma/inmunología , Mycoplasma/aislamiento & purificación , Infecciones por Mycoplasma/prevención & controlRESUMEN
Monoclonal antibodies (mabs) against Mycoplasma (M.) bovis were prepared for use in diagnosis of bovine mastitis. From the original 32 hybridomas actively secreting mabs against M. bovis, 6 stable lines were cloned. Two of them, Mb 5D8 and Mb 4F6, recognized M. bovis antigens of estimated molecular weights of 33 and 26 kDa, respectively. They showed no cross-reaction to other bovine mycoplasmas, thus rendering them useful for specific detection of this pathogen. All mabs investigated cross-reacted with M. agalactiae which is known to be closely related to M. bovis, but does not occur in cattle. Two other mabs, Mb 5D4 and Mb 1F6, exhibited further cross-reactions to a number of bovine mycoplasma species. Finally, mabs Mb 5D5 and Mb 2G5 reacted with all mycoplasmas tested. The possibility that they recognized constituents of the broth culture medium is discussed.
Asunto(s)
Anticuerpos Monoclonales/biosíntesis , Antígenos Bacterianos/inmunología , Mastitis Bovina/diagnóstico , Leche/microbiología , Mycoplasma/inmunología , Animales , Bovinos , Hibridomas , Mycoplasma/aislamiento & purificaciónRESUMEN
Whole-cell protein patterns generated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) were compared for 34 isolates of Mycoplasma bovis. A high degree of similarity between most of the strains was established with strain-to-strain differences mainly confined to quantitative variations of certain protein bands, particularly in the molecular weight regions of 64-68, 55 and 26 kD. Two of the isolates provided more deviating patterns. Hydrophobic membrane protein fractions of the strains as prepared by Triton X-114 phase partitioning were compared by SDS-PAGE, which confirmed some of the characteristic strain features found with whole-cell proteins. The immunoblot analysis revealed that up to 20 of the 50-55 discrete protein bands detected in SDS-PAGE patterns were recognized to be antigenic by rabbit and bovine hyperimmune sera. It is concluded that the same set of major antigens is present in all strains investigated, but amounts of individual constituents may be differing.
Asunto(s)
Antígenos Bacterianos/análisis , Proteínas Bacterianas/análisis , Mycoplasma/química , Animales , Bovinos , Electroforesis en Gel de Poliacrilamida , Immunoblotting , Peso Molecular , Mycoplasma/inmunologíaRESUMEN
A total of 31 primary cell culture preparations of calf kidney including their processing stages (kidney, washing fluid, cell suspension, cell culture monolayer) were investigated for mycoplasmas by cultural methods. Mycoplasma (M.) arginini, was isolated from 8 out of 27 investigated samples of calf kidney from 3 out of 26 washing fluids, 5 out of 20 cell suspensions, and from 9 out of 21 cell culture monolayers. Furthermore, M. arginini was repeatedly found in throat swabs of the cell laboratory technicians. The results give indications as to the source and route of mycoplasma infections of primary cell cultures.
Asunto(s)
Riñón/microbiología , Mycoplasma/aislamiento & purificación , Animales , Bovinos , Enfermedades de los Bovinos/microbiología , Células Cultivadas , Humanos , Riñón/citología , Infecciones por Mycoplasma/veterinariaRESUMEN
Twelve freshly lactating ewes were experimentally infected with 2 Mycoplasma (M.) bovis strains via the teat canal in the left udder. The M. bovis infection produced a febrile clinical mastitis in all infected animals. M. bovis could be re-isolated regularly from the experimentally infected udder halves and the infection spread to the other halves. Some contact animals and 4 suckling lambs became naturally infected. Antibody titres were detected by means of the indirect hemagglutination test in blood sera 2 to 3 weeks post infectionem. The pathological lesions were similar to those of the M. bovis mastitis of cows. By the end of the trial the ewes had recovered from the clinical mastitis.
Asunto(s)
Mastitis/veterinaria , Infecciones por Mycoplasma/veterinaria , Mycoplasma/patogenicidad , Enfermedades de las Ovejas/microbiología , Animales , Femenino , Mastitis/microbiología , Infecciones por Mycoplasma/microbiología , OvinosRESUMEN
Electron microscopic investigations on the respiratory tract of piglets with and without Mycoplasma hyorhinis infection (10th day of life) partly combined with swim stress (15 degrees C water temperature) (n = 20/20) yielded the following results: colonization of Mycoplasma hyorhinis in the ciliary zone of trachea and bronchi in 15 out of 40 piglets (37.5%); the evidence rate of Mycoplasma hyorhinis in pneumonic lungs (8 out of 12 = 66.7%) was significantly higher than in nonpneumonic lungs (7 out of 28 = 25.0%) and highest in experimentally infected piglets with swim stress (9 out of 16 = 56.2%). Ultrastructural lesions: loss of cilia; bleb-formation; hydropic degeneration and desquamation of ciliary cells; the occurrence of cilia-free and immature epithelial cells; alveolar collapse; microatelectasis; oedematous swelling of pneumocyte I; accumulation of surfactant in the alveoli; hyperplasia of pneumocyte II; exudation of mononuclear macrophages and neutrophils with numerous digestion vacuoles; several lymphocytes and plasma cells, only a little lymphohistiocytic interstitial and peribronchial infiltration. Phagocytized mycoplasmas were found within the resorption vacuoles of neutrophils in the tracheobronchial area, for this once in alveoli, not (more) against in alveolar macrophages. The results were discussed with regard to etiology and pathogenicity of enzootic pneumonia in pigs.