Contagious agalactia: costs and control revisited.

The economic costs of contagious agalactia (CA) to the small ruminant dairy industry are not well known but include losses due to mortality, lowered milk production, spoiled products, abortions and animal welfare problems, as well as diagnosis and treatment. This paper reports financial estimates made in southern Europe, including a study on small- and large-scale farming systems in Italy, indicating that the financial losses are high and underestimated. Furthermore, the current control strategies, including chemotherapy and vaccination, in selected countries in Europe are described. In some countries, disease control is hampered by excessively strict veterinary legislation which discourages farmers and private veterinarians from notifying outbreaks because it leads to the prohibition of milk sales and can result in delays in lifting restrictions. In addition, new European Union legislation may downgrade the importance of CA, which will have implications for international research efforts. Finally, a series of recommendations are provided that cover the proper notification and handling of CA outbreaks, including movement control, current diagnostics, treatment, vaccination and disinfection.

Si le coût économique exact de l'agalaxie contagieuse pour le secteur ovin et caprin de production laitière n'est pas connu, on sait néanmoins qu'il recouvre les pertes dues à la mortalité dans les cheptels, à une chute de la production de lait, aux produits altérés, aux avortements et aux problèmes de bien-être animal, en plus des coûts du diagnostic et des traitements. Les auteurs font état d'estimations financières réalisées en Europe méridionale, dont une étude sur les exploitations familiales et les élevages de grande taille en Italie, qui coïncident dans le constat de pertes financières à la fois importantes et sous-estimées. Les auteurs décrivent également les stratégies de lutte mises en place actuellement par plusieurs pays d'Europe, en particulier l'antibiothérapie et la vaccination. Dans certains pays, les efforts de lutte sont entravés par une législation vétérinaire excessivement rigoureuse qui dissuade les éleveurs et les vétérinaires privés de notifier les foyers car cela entraîne l'interdiction de vendre le lait issu des troupeaux infectés et retarde la levée des mesures de restriction. En outre, la nouvelle réglementation de l'Union européenne risque d'abaisser l'importance de l'agalaxie contagieuse, ce qui aura des conséquences sur les efforts mobilisés par la recherche au niveau international. Pour conclure, les auteurs formulent plusieurs recommandations en vue d'une notification et gestion appropriées des foyers d'agalaxie contagieuse, notamment pour ce qui concerne le contrôle des mouvements d'animaux, les méthodes actuelles de diagnostic, le traitement, la vaccination et la désinfection.

Aunque no se conocen bien los costos económicos que la agalaxia contagiosa inflige a la industria lechera de pequeños rumiantes, se sabe que las pérdidas por mortalidad, mengua de la producción lechera, productos echados a perder, abortos y problemas de bienestar animal son un factor importante, sin olvidar los gastos de diagnóstico y tratamiento. Los autores dan cuenta de cálculos económicos realizados en Europa meridional, en particular a raíz de un estudio de pequeñas y grandes explotaciones ganaderas de Italia, que llevaron a la conclusión de que las pérdidas económicas son cuantiosas y están subestimadas. Además, los autores describen los métodos de lucha aplicados actualmente en determinados países de Europa, que incluyen tratamiento medicamentoso y vacunaciones. En algunos países la lucha contra la enfermedad se ve lastrada por una legislación veterinaria demasiado estricta, que no alienta a productores y veterinarios privados a notificar brotes porque ello conduce a la prohibición de las ventas de leche y puede demorar el levantamiento de las restricciones. Por otra parte, hay nuevos textos legislativos de la Unión Europea que quizá vengan a restar importancia a la agalaxia contagiosa, lo que repercutiría en las actividades internacionales de investigación. Por último, los autores formulan una serie de recomendaciones referidas a cuestiones que van desde la correcta notificación y gestión de los brotes de agalaxia contagiosa hasta el control de los desplazamientos, pasando por los procedimientos vigentes de diagnóstico o los métodos de tratamiento, vacunación y desinfección.

Survey of contagious caprine pleuropneumonia in goat herds in the Thrace region of Turkey.

Contagious caprine pleuropneumonia (CCPP) was detected for the first time on the European continent in the Thrace region of Turkey in 2002 following outbreaks of an unusually severe respiratory disease in goats. Mycoplasma capricolums ubspecies capripneumoniae (Mccp), the causative agent, was identified in many infected herds throughout the region by serological, bacteriological and molecular biological techniques. However, as no quantitative data on the prevalence and distribution of the disease have been gathered in the intervening years, the extent of infection is unknown. Consequently, in 2014, a random sample of 2,400 goats was drawn from a population of over 167,000 goats in the region by multistage sampling. Serum samples were collected and tested by a monoclonal antibodybased competitive enzyme-linked immunosorbent assay (cELISA). The overall prevalence of CCPP in Thrace was found to be just over 8%. The prevalence in the individual provinces was approximately 18%, 7%, 8% and 6% for Çanakkale, Edirne, K?rklareli and Tekirda?, respectively, while Istanbul province appeared to be CCPP-free. The results showed that CCPP has spread throughout the region and has become endemic, and may pose a potential risk to the neighbouring countries of Greece and Bulgaria. Mccp was regularly detected from lung samples of suspect goats until 2015 but since then there has been no further detection from clinical samples.

La pleuropneumonie contagieuse caprine (PPCC) était détectée pour la première fois sur le continent européen en Thrace orientale (Turquie) en 2002, à la suite de foyers d'une maladie respiratoire particulièrement sévère affectant le cheptel caprin. L'agent causal identifié par diverses méthodes sérologiques, bactériologiques et de biologie moléculaire dans plusieurs troupeaux infectés de la région était Mycoplasma capricolum sous-espèce capripneumoniae (Mccp). Cependant, en l'absence de données quantitatives sur la prévalence et la distribution de la maladie depuis ces foyers, l'extension de l'infection est restée inconnue. Pour y remédier, un échantillonnage stratifié et aléatoire de2 400 chèvres parmi une population de plus de 167 000 chèvres de la région a été réalisé en 2014. L'analyse par la méthode immunoenzymatique de compétition (cELISA) faisant appel à des anticorps monoclonaux des sérums collectés a montré que la prévalence globale pour la Thrace orientale était un peu au-dessus de 8 %. Dans les provinces de Çanakkale, d'Edirne, de K?rklareli et de Tekirda?, la prévalence était respectivement de 18 %, 7 %, 8 % et 6 % tandis qu'Istanbul était indemne de PPCC. Ces résultats montrent que la PPCC est devenue endémique dans l'ensemble de la région et représente un risque potentiel pour les pays avoisinants, c'est-à-dire la Grèce et la Bulgarie. Jusqu'en 2015, Mccp a été régulièrement détectée dans les échantillons de poumon prélevés chez des chèvres suspectées infectées mais depuis cette date aucun échantillon clinique n'a été testé positif.

En 2002 se detectó por primera vez la pleuroneumonía contagiosa caprina en el continente europeo, a raíz de una serie de brotes de enfermedad respiratoria de inusitada gravedad que afectaron a cabras de la región turca de Tracia. Empleando técnicas serológicas, bacteriológicas y de biología molecular, se detectó en muchos rebaños infectados de toda la región la presencia del agente causal, Mycoplasma capricolum subespecie capripneumoniae (Mccp). Sin embargo, se desconoce el alcance de la infección, porque en los años transcurridos desde entonces no se han reunido datos cuantitativos sobre la prevalencia y distribución de la enfermedad. Por consiguiente en 2014, a partir de una población de más de 167.000 cabras de la región, se obtuvo por muestreo multietápico una muestra aleatoria de 2.400 ejemplares, a los que se extrajeron muestras de suero que fueron sometidas a un ensayo inmunoenzimático de competición (ELISAc) con anticuerpos monoclonales. Se calculó que la prevalencia global de pleuroneumonía contagiosa caprina en Tracia era algo superior al 8%. Por provincias, la prevalencia resultó de alrededor de un 18%, un 7%, un 8% y un 6% en las provincias de Çanakkale, Edirne, K?rklareli y Tekirda?, respectivamente, mientras que la provincia de Estambul resultó estar libre de la infección. Estos resultados demostraron que la enfermedad se ha extendido por toda la región, ha cobrado carácter endémico y puede amenazar a los países vecinos, como Grecia y Bulgaria. Hasta 2015 se detectó regularmente la presencia de Mccp en muestras pulmonares de cabras sospechosas, pero desde entonces no se ha vuelto a observar tal cosa en ninguna muestra clínica.

Search for OIE-listed ruminant mycoplasma diseases in Afghanistan.

BACKGROUND: Little is known about the occurrence of important diseases of ruminants in Afghanistan because of the conflict affecting the country over the last 40 years. To address this discrepancy, ruminant herds in Afghanistan were screened for OIE-listed mycoplasma diseases, contagious bovine (CBPP) and caprine pleuropneumonias (CCPP). RESULTS: Of the 825 samples from 24 provinces tested for serological evidence of CBPP caused by Mycoplasma mycoides subsp.mycoides, 20 (3.4%) had ELISA values greater than the positive threshold of 50% though all were less than 55%. Repeat testing of these suspect sera gave values below 50. A smaller number of sera (330) from cattle in nine provinces were also tested by the rapid latex agglutination test (LAT) for CBPP, 10 of which were considered suspect. However, no positive bands were seen when immunoblotting was carried out on all sera that gave suspect results. Serological evidence of Mycoplasma bovis was detected in half of 28 herds in eight provinces. The cause of CCPP, M. capricolum subsp. capripneumoniae was not detected in any of the 107 nasal swabs and lung tissue collected from goats in seven provinces though sample handling and storage were not optimal. However, strong serological evidence was detected in goat herds in several villages near Kabul some of which were over 50% seropositive by LAT and ELISAs for CCPP; immunoblotting confirmed positive results on a selection of these sera. CONCLUSIONS: The data presented here provide a first assessment of the occurrence of the two OIE listed mycoplasma diseases in Afghanistan. From the results of the testing bovine sera from the majority of provinces there is no evidence of the presence of CBPP in Afghanistan. However the samples tested represented only 0.03% of the cattle population so a larger survey is required to confirm these findings. Serological, but not bacterial, evidence was produced during this investigation to show that CCPP is highly likely to be present in parts of Afghanistan.

16S rRNA gene mutations associated with decreased susceptibility to tetracycline in Mycoplasma bovis.

Mycoplasma bovis isolates with decreased susceptibilities to tetracyclines are increasingly reported worldwide. The acquired molecular mechanisms associated with this phenomenon were investigated in 70 clinical isolates of M. bovis. Sequence analysis of the two 16S rRNA-encoding genes (rrs3 and rrs4 alleles) containing the primary binding pocket for tetracycline (Tet-1 site) was performed on isolates with tetracycline hydrochloride MICs of 0.125 to 16 µg/ml. Mutations at positions A965T, A967T/C (Escherichia coli numbering) of helix 31, U1199C of helix 34, and G1058A/C were identified. Decreased susceptibilities to tetracycline (MICs, ≥2 µg/ml) were associated with mutations present at two (A965 and A967) or three positions (A965, A967, and G1058) of the two rrs alleles. No tet(M), tet(O), or tet(L) determinants were found in the genome of any of the 70 M. bovis isolates. The data presented correlate (P<0.0001) the mutations identified in the Tet-1 site of clinical isolates of M. bovis with decreased susceptibility to tetracycline.

Global multilocus sequence typing analysis of Mycoplasma bovis isolates reveals two main population clusters.

Mycoplasma bovis is a major bovine pathogen associated with bovine respiratory disease complex and is responsible for substantial economic losses worldwide. M. bovis is also associated with other clinical presentations in cattle, including mastitis, otitis, arthritis, and reproductive disorders. To gain a better understanding of the genetic diversity of this pathogen, a multilocus sequence typing (MLST) scheme was developed and applied to the characterization of 137 M. bovis isolates from diverse geographical origins, obtained from healthy or clinically infected cattle. After in silico analysis, a final set of 7 housekeeping genes was selected (dnaA, metS, recA, tufA, atpA, rpoD, and tkt). MLST analysis demonstrated the presence of 35 different sequence types (STs) distributed in two main clonal complexes (CCs), defined at the double-locus variant level, namely, CC1, which included most of the British and German isolates, and CC2, which was a more heterogeneous and geographically distant group of isolates, including European, Asian, and Australian samples. Index of association analysis confirmed the clonal nature of the investigated M. bovis population, based on MLST data. This scheme has demonstrated high discriminatory power, with the analysis showing the presence of genetically distant and divergent clusters of isolates predominantly associated with geographical origins.

First isolation of Mycoplasma iowae in grey partridge flocks.

Mycoplasma iowae, an occasional pathogen of turkeys, was isolated for the first time from captive grey partridges (Perdix perdix). Clinical signs including respiratory and intestinal disorder were seen in birds of all ages but mainly in those kept housed during rearing. Mortality rates averaged over 20% during the year. Treatment with antibiotics and antiparasitic drugs produced only a transient improvement in condition. The gross pathology findings included poor body growth, lack of development of the breast muscles, abnormalities in the keel development, and bone fragility. Some birds showed infraorbital sinusitis with serous or fibrinous exudates and catarrhal tracheitis, while others presented serofibrinous airsacculitis and splenomegaly. Laboratory investigations revealed pure cultures of M. iowae in the gut as well as sinus and air sacs. While other organisms such as coccidia, Trichomonas, Escherichia coli, Clostridium perfringens, and Aspergillus spp. were detected, the similarity of the disease with that seen in turkeys infected with M. iowae strongly suggests that this mycoplasma may be the primary pathogen here. The presence of M. iowae in game birds commonly released into the wild could have serious implications particularly in areas where industrial poultry farms are concentrated.

Isolation, molecular characterization and antimicrobial susceptibilities of isolates of Mycoplasma agalactiae from bulk tank milk in an endemic area of Spain.

AIM: To isolate and characterize strains of Mycoplasma agalactiae from bulk tank and silo ewes' milk. METHODS AND RESULTS: Thirteen mycoplasma isolates were obtained from samples of sheep milk taken from bulk tank and large silos and identified as Myc. agalactiae by PCR-DGGE. The isolates were typed by pulsed field gel electrophoresis (PFGE), SDS-PAGE and immunoblot. The in vitro activity of 13 antimicrobials of veterinary interest was tested against these isolates. Results showed that the most effective compounds against Myc. agalactiae in vitro were clindamycin, an antibiotic not previously described as a suitable contagious agalactia (CA) treatment, with Minimum Inhibitory Concentration (MIC) values of <0·12 µg ml(-1) , and quinolones, with MIC values <0·12-0·5 µg ml(-1) , which are used as standard treatments against CA. CONCLUSIONS: Based on the in vitro assay, clindamycin, quinolones, tylosin and tilmicosin would be appropriate antimicrobials for CA treatment. The isolates were mostly resistant to erythromycin, indicating that it would not be a suitable choice for therapy. The isolates showed common molecular and protein profiles by PFGE and SDS-PAGE, with minor differences observed by immunoblot analysis, suggesting a clonal relationship among them. SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrated the importance of the appropriate selection of antimicrobials for treatment of CA.

Mycoplasma neophronis sp. nov., isolated from the upper respiratory tract of Canarian Egyptian vultures (Neophron percnopterus majorensis).

Six strains with the typical characteristics of mycoplasmas were isolated from the tracheae of six Canarian Egyptian vultures (Neophron percnopterus majorensis). The results of biochemical, serological and molecular genetic studies showed that the isolates were nearly identical and that they could be considered as representing a novel species of the genus Mycoplasma. Colonies possessed the typical fried-egg appearance and electron micrographs revealed a pleomorphic cellular morphology with the lack of a cell wall. The isolates hydrolysed arginine and required sterol for growth but did not ferment glucose or hydrolyse urea. We propose that the isolates be assigned to a novel species,Mycoplasma neophronis sp. nov. The type strain is G.A.(T) ( = DSM 24097(T) = ATCC BAA-2157(T)). The antiserum of strain G.A.(T) has been deposited in the Mollicutes collection at Purdue University (Indiana, USA).

Investigations into an outbreak of corvid respiratory disease associated with Pasteurella multocida.

The possible cause of disease and mortality in corvids on an outdoor pig unit in the north of England between August 2007 and March 2008 was investigated. Nine carrion crows (Corvus corone corone) and nine rooks (Corvus frugilegus), comprising five live-caught birds with clinical signs of respiratory disease, one live-caught bird without respiratory disease, and 12 birds submitted dead were examined. Clinical signs, gross and histopathological examination, microbiology and toxicology indicated that Pasteurella multocida infection was the cause of disease. Molecular and serotyping analyses showed that P. multocida isolates (obtained from live-caught birds with clinical respiratory disease) were all capsular type F with a mix of somatic serotypes 3, 4 and 7. Immunohistochemistry increased the diagnostic sensitivity of the analysis and detected P. multocida within the pulmonary lesions of all affected live-caught birds and 10 of 12 birds found dead. These findings suggest that wild corvids in the UK can suffer from lung pathology associated with P. multocida and, as potential vectors of P. multocida, may pose a risk to domestic poultry.

Biochemical and genetic variation in Mycoplasma fermentans strains from cell line, human and animal sources.

AIMS: To investigate the inter-strain variation in (i) substrate utilization and (ii) the restriction fragment length polymorphism (RFLP) pattern based on the distribution of an insertion element (IS1550) in Mycoplasma fermentans strains, and to establish any correlation between subgroups within the species and their source or habitat. METHODS AND RESULTS: Using a sensitive dynamic pH method, the pattern and kinetics of substrate utilization by a panel of 17 M. fermentans strains from various sources was determined. This study correlated the biochemical characteristics of these strains with RFLP patterns based on the distribution of an insertion sequence (IS1550) with the sources of the strains. The test isolates were divided into four major groups according to the pattern of substrates metabolized. Interestingly, two strains isolated from cell lines in RFLP cluster I failed to utilize arginine. Ovine strains showed distinct substrate utilization patterns and produced RFLP patterns not previously encountered. CONCLUSIONS: All strains utilized glucose, but the ability to utilize arginine, fructose and N-acetyl glucosamine varied. There was also some correlation evident between the metabolic data and the RFLP clusters. SIGNIFICANCE AND IMPACT OF THE STUDY: This study has provided a better understanding of the biochemical and genetic diversity of M. fermentans strains from various sources.

Tetrazolium reduction methods for assessment of substrate oxidation and strain differentiation among mycoplasmas, with particular reference to Mycoplasma bovigenitalium and some members of the Mycoplasma mycoides cluster.

AIMS: To apply a rapid nitroblue tetrazolium (NBT) reduction assay of substrate metabolism by mycoplasmas that would help to differentiate Mycoplasmas. METHODS AND RESULTS: Growth, substrate preferences and tetrazolium reduction were assessed for 18 strains of Mycoplasma bovigenitalium and Mycoplasma ovine serogroup 11. NBT reduction was detectable in 1 h with 10(8) CFU ml(-1). Use of alpha-ketobutyrate, lactate and pyruvate to support growth and NBT reduction were correlated: pyruvate was preferred and lactate was used by only four of the 18 strains. Selected members of the Mycoplasma mycoides cluster were also assessed and monotetrazoles tested as alternatives to NBT. The NBT method was applied to a further 19 species. CONCLUSIONS: This simple and reproducible method requires only small amounts of cells, enabling routine assessment of substrate use within 1 h, and the rapid assignment of numerous mycoplasmas to one of six physiological groups. The four physiological groups of M. bovigenitalium and Mycoplasma serogroup 11 strains were indistinguishable from each other, which supports the view that these belong to the same species. SIGNIFICANCE AND IMPACT OF THE STUDY: Strain-specific substrate-utilization patterns by mycoplasmas can be obtained rapidly and reliably. The method has potential as a large-scale semi-automated procedure to monitor numerous strains and substrates simultaneously.

Bacteriological, serological, pathological and immunohistochemical studies of Mycoplasma bovis respiratory infection in veal calves and adult cattle at slaughter.

Mycoplasma bovis is an important cause of calf pneumonia worldwide. In this study, we examined 140 cattle at slaughter comprising 70 veal calves and 70 beef cattle; 115 animals with pneumonic lesions and 25 without. Lung samples were submitted for bacteriological, histological, and M. bovis-immunohistochemical analyses. Serology for M. bovis was positive in 76% of beef cattle and 100% of veal calves. M. bovis was isolated only from veal calves in 16 out of 64 pneumonic cases. M. bovis was detected by immunohistochemistry in seven bacteriologically positive cases. M. bovis antigen was associated with bronchogenic necrosuppurative or fibrinonecrotizing lesions. Bacteriologically positive and immunohistochemical negative cases were associated with catarrhal bronchointerstitial pneumonia. Results suggest that M. bovis infection may develop into a severe necrosuppurative bronchopneumonia or fibrinonecrotizing pneumonia when associated with a high number of intralesional organisms or, conversely, into a mild catarrhal bronchointerstitial pneumonia when associated with a low number of organisms.

Isolation and immunological detection of Mycoplasma ovipneumoniae in sheep with atypical pneumonia, and lack of a role for Mycoplasma arginini.

Mycoplasma ovipneumoniae NCTC 10151(T) and four new isolates from UK sheep flocks were compared. Only glucose and pyruvate were used as energy sources by the five strains: glucose was the best energy source for the type strain, pyruvate supported better growth of the new strains. Whole cell protein patterns and antigenic profiles showed high similarity between all five strains. The new isolates fell into two groups in ELISA tests. Serum samples from 30 pneumonic sheep were assessed for M. ovipneumoniae infection and Mycoplasma arginini co-infection. Fourteen (out of 30) serum samples were positive for M. ovipneumoniae both by ELISA and immunoblotting. Twelve antigenic proteins of M. ovipneumoniae were detected in infected serum samples: the antigen patterns were unique, with between one and at least seven occurring in any one sample. All serum samples were designated as negative for M. arginini antibodies by both ELISA and immunoblotting.

Isolation and characterization of unusual Mycoplasma spp. from captive Eurasian Griffon (Gyps fulvus) in Sicily.

Mycoplasmas have been isolated from birds of prey during clinical examinations, but their significance to the health of raptors is unclear. We report the isolation and characterization of four mycoplasmas found in the upper respiratory tract of four sick Eurasian Griffon (Gyps fulvus) that were housed in a Sicilian rehabilitation center at Ficuzza, near Palermo in Sicily, before reintroduction into the wild. These included Mycoplasma gallinarum, an unidentified mycoplasma highly similar to Mycoplasma glycophilum, and two unidentified mycoplasmas with similarities to Mycoplasma falconis and Mycoplasma gateae.

Gap analysis of Mycoplasma bovis disease, diagnosis and control: An aid to identify future development requirements.

There is a worldwide problem of disease caused by Mycoplasma (M.) bovis in cattle; it has a significant detrimental economic and animal welfare impact on cattle rearing. Infection can manifest as a plethora of clinical signs including mastitis, pneumonia, arthritis, keratoconjunctivitis, otitis media and genital disorders that may result in infertility and abortion. Current diagnosis and control information are reviewed and analysed to identify gaps in knowledge of the causative organism in respect of the disease pathology, diagnosis and control methods. The main considerations are as follows: no vaccines are commercially available; antimicrobial resistance is increasing; diagnostic and antimicrobial sensitivity testing needs to be improved; and a pen-side test would facilitate more rapid diagnosis and implementation of treatment with antimicrobials. More data on host susceptibility, stress factors, immune response and infectious dose levels are required. The impact of asymptomatic carriers, M. bovis survival in the environment and the role of wildlife in transmitting the disease also needs investigation. To facilitate development of vaccines, further analysis of more M. bovis genomes, its pathogenic mechanisms, including variable surface proteins, is required, along with reproducible disease models.

A high level of strain variation within the Mycoplasma ovipneumoniae population of the UK has implications for disease diagnosis and management.

Mycoplasma ovipneumoniae is one of only two mycoplasma species associated with small ruminant disease in Britain and has been associated with an increasing number of disease outbreaks since 2002. This investigation used well-defined techniques to assess the variability of UK M. ovipneumoniae isolates, in an attempt to identify strain clusters within the population. Strains received for routine diagnosis between 2002 and 2004 were analysed using random amplified polymorphic DNA (RAPD) and pulsed field gel electrophoresis (PFGE). Of the 43 samples screened 40 RAPD Hum-1, 41 RAPD Hum-4 and 40 PFGE profiles were observed. Composite data analysis divided strains into 10 similarity clusters with SDS-PAGE and Western blotting indicating that this DNA variability is translated into a pattern of variable protein expression. In order to assess the strains isolated within flocks two sets of samples, from diverse locations, were included in this test panel. The presence of variable isolates existing on the same farm may reflect animal movement and the introduction of asymptomatic, carrier, animals where M. ovipneumoniae is already established within a flock. These findings have significant implications regarding disease diagnosis and management.

Mycoplasma host specificity: fact or fiction?

Bacteria of the genus Mycoplasma are the smallest organisms known to be capable of self-replication. They only occur in association with animal host cells on which they are dependant for many pre-formed nutrients since they lack many of the metabolic pathways associated with energy production and the synthesis of cell components found in other species of bacteria. It is generally thought that most species of Mycoplasma are very host specific but there are many reports of mycoplasmas in hosts that are not perceived as their normal habitat. Sometimes these "crossings" may have a pathological impact particularly where there may be predisposing conditions such as immunodeficiency. These are often reported in humans but may also occur in animals whose immune or physiological status is not known. This review brings together some of these reported incidents and speculates on their potential impact for laboratory diagnosis.

Hydrogen peroxide production by Mycoplasma bovis and Mycoplasma agalactiae and effect of in vitro passage on a Mycoplasma bovis strain producing high levels of H2O2.

Hydrogen peroxide (H2O2) production and oxygen uptake during the oxidation of NADH and L-alpha-glycerophosphate (GP) by lysed cells was determined for the type and field strains of Mycoplasma bovis and M. agalactiae. NADH oxidation by all the strains showed variable production of H2O2 ranging from 0 to 1.21 mol/mol O2 taken up. All strains were unable to oxidize GP, showing absence of GP oxidase activity. Some strains were identified that produced relatively high levels of H2O2 (> 1.0 mol/ mol O2 taken up). In vitro passage of M. bovis strain 119B96 showed reduced H2O2 production: 0.52, 0.16, and 0.07 mol/mol O2 taken up after the 50th, 100th and 200th passages, respectively. SDS-PAGE analysis showed the loss of a protein band of 32 kDa after 50 passages. These preliminary studies show that not only does H2O2 production by potentially pathogenic Mycoplasma spp. vary in the field but also that similar alterations can be induced by passage in culture. In the latter case, at least in one M. bovis strain, this alteration has been shown by SDS-PAGE to be associated with a loss of specific protein production. Further study of these phenomena is essential background for the production of more efficient vaccines for mycoplasmas.

Mycoplasma bovis: disease, diagnosis, and control.

Mycoplasma bovis is a major, but often overlooked, pathogen causing respiratory disease, mastitis, and arthritis in cattle. It is found worldwide and has spread into new areas, including Ireland and parts of South America, in the last decade. In Europe, it is responsible for at least a quarter to a third of all calf pneumonia although this may be an underestimate as few laboratories regularly monitor for mycoplasmas. Like all mollicutes, M. bovis is inherently refractory to certain groups of antibiotics because it does not possess a cell wall; furthermore evidence is accumulating that strains of M. bovis are becoming resistant to antibiotics, including tetracycline, tilmicosin and spectinomycin, traditionally used for their control. No vaccines are presently available for the control of M. bovis infections.