An Investigation of Ovine Pneumonia in Four Herds from Central Norway: I. Prevalence of Pneumonia and Microbiological Findings

In a study of 4 sheep herds, 1 apparently healthy and 3 having respiratory problems, lesions typical of subacute or chronic pneumonia were found in 3–36 % of slaughtered lambs. Occurrence appeared to be related to certain environmental factors such as pasture, whereas moderate lungworm invasion was not found to contribute to subacute or chronic pneumonia. Relation between pneumonia and low carcass weight was established only in 1 herd.Lungs were subjected to microbiological examination. Mycoplasma ovipneumoniae was isolated from both normal and pneumonic lungs from all 4 herds. The prevalence was far higher in pneumonic (98 %) than in normal ones (28 %). Bacteria, mostly Pasteurella haemolytica, were also found in both pneumonic (49 %) and normal (18 %) lungs from all 4 herds. These results confirm the conclusions of a previous study that M. ovipneumoniae is of etiological significance in subacute or chronic pneumonia, whereas bacteria mainly occur as secondary invaders. M. ovipneumoniae appears, however, only to be a potential pathogen. Examinations for Mycoplasma arginini and virus were negative and these agents are considered to be of less significance in subacute or chronic pneumonia under Norwegian conditions.     

An Investigation of Ovine Pneumonia in Four Herds from Central Norway: II. Relation Between Pathomorphology and Presence of Micro-Organisms

Sheep lungs obtained at slaughter from 4 herds from Central Norway were subjected to a macroscopical examination. Gross pulmonary findings included normal lungs, fibrous pleurisy, verminous nodules, atelectasis and consolidations of lobular and lobar extensions. A selection of lungs representing the various gross findings was subjected to microbiological and histological examinations. Pleurisy was associated wtih pneumonic consolidations and extension of lesions. Verminous nodules indicative of Muellerius spp. migrations occurred irrespective of gross pulmonary lesions or microbiological findings. A subacute or chronic pneumonia of a mixed proliferative exudative type was demonstrated in consolidated tissue. An association was found between the isolation of Mycoplasma ovipneumoniae and the presence of pneumonic lesions and between the number of organisms and extension of lesions. Histological findings highly indicative of this organism were proliferative changes in the bronchiolar and bronchial epithelium and intrapulmonary lymphoid tissue. The intensity of these changes was correlated to the number of mycoplasma organisms present. Mycoplasma ovipneumoniae is suggested to be of primary etiological significance regarding subacute or chronic pneumonia in lambs at slaughter.     

Mycoplasma species and related organisms isolated from ruminants in Britain between 1990 and 2000

Between 1990 and 2000, more than 1600 mycoplasmas and the related acholeplasmas were identified from ruminant animals by the Mycoplasma Group at the Veterinary Laboratories Agency--Weybridge. Mycoplasma bovis was the most commonly identified pathogen, mostly from pneumonic calves but occasionally from cattle with mastitis and arthritis. Mycoplasma canis was first isolated in Britain in 1995 from pneumonic calves and the number of isolates increased to 18 per cent of the total mycoplasmas isolated from cattle in 1999. The ELISA for antibodies to M. bovis detected 1971 positive samples (22 per cent) among 8959 serum samples, mainly from pneumonic cattle. Other mycoplasmas identified included Mycoplasma dispar from the lungs of cattle with respiratory disease, and Mycoplasma bovigenitalium from the reproductive tract of cows with vulvovaginitis and infertility. Mycoplasma bovirhinis and Acholeplasma species were found commonly but are thought to be more opportunistic than pathogenic. In sheep and goats, the majority of Mycoplasma species isolated were identified as Mycoplasma ovipneumoniae from pneumonic sheep, Mycoplasma conjunctivae from sheep with keratoconjunctivitis, and the ubiquitous Mycoplasma arginini.     

Chronic non-progressive pneumonia of sheep in New Zealand - a review of the role of Mycoplasma ovipneumoniae

Chronic non-progressive pneumonia (CNP) is a common disease which affects lambs in New Zealand during late summer and autumn. Mycoplasma ovipneumoniae can be recovered from a high proportion of lesions but it is also present in some normal lungs. Bacteria, especially Pasteurella haemolytica, can also be recovered from more than half the lungs of affected animals. Isolates of M. ovipneumoniae are genetically heterogeneous, as demonstrated by examination of their DNA or total cellular proteins, and are serologically heterogeneous as shown by metabolic inhibition tests. The number of strains present in New Zealand is large and several distinguishable strains can be recovered from each affected lung. Mycoplasma ovipneumoniae has pathogenic potential as indicated by its ability to produce hydrogen peroxide, cause ciliostasis and by its possession of a capsule. Chronic non-progressive pneumonia can be transmitted consistently to over 50% of lambs by inoculation of pooled pneumonic lung homogenate and transmission can be suppressed by broad spectrum antibiotics. In contrast, penicillin does not prevent the development of lesions but diminishes their severity. Pooled lung homogenate treated with digitonin, which inactivates mycoplasmas, has failed to transmit CNP. Pure cultures of M. ovipneumoniae produce only mild lesions in some animals, whereas inoculation with pooled lung homogenate (from which no viruses were isolated) containing mixed strains of M. ovipneumoniae and free from bacteria, is more effective in producing lesions. Research work to date suggests that CNP may be initiated by colonisation of the lung by M. ovipneumoniae which causes ciliostasis and elicits an exudate allowing colonisation of the lungs by bacteria especially M. haemolytica and by other strains of M. ovipneumoniae. The immune response to the initial strain of M. ovipneumoniae may inhibit its replication but would be less effective in inhibiting heterologous strains of the organism allowing their sequential replication. Eventually production of a broad immune response to M. ovipneumoniae would lead to its elimination which in turn would facilitate the elimination of other microorganisms and the resolution of lesions. As natural immunity to CNP occurs within the first year, it may be possible to develop an effective and useful vaccine. Such a vaccine may need to include multiple strains of M. ovipneumoniae.     

Comparison of virulence of ovine respiratory mycoplasmas in the mouse mammary gland

The virulence of isolates of Mycoplasma ovipneumoniae and M. arginini from pneumonic and unaffected ovine lungs was compared in a mouse mammary gland model. The isolates varied in their ability to induce a neutrophilic response in the mammary gland. A moderate to severe form of mastitis was induced by 3 M. ovipneumoniae isolates recovered from pneumonic lungs, while the remaining M. ovipneumoniae isolates from pneumonic lungs and those from unaffected lungs induced a very mild histopathological response. The severity of the mastitis could not be increased by the simultaneous inoculation of a mixture of 5 mycoplasma isolates. Mycoplasma arginini isolates induced only a very mild histopathological response despite having been isolated from pneumonic lungs. The finding that the 3 most virulent M. ovipneumoniae isolates were initially recovered from pneumonic ovine lungs suggested that these virulent isolates may contribute to ovine pneumonia. However, the isolation of M. ovipneumoniae from pneumonic ovine lungs does not necessarily imply that these organisms are the causal agents, since M. ovipneumoniae isolates may vary in virulence.     

Microbiological and serological studies on caprine pneumonias in Oman

Eight of 10 typical cases of contagious caprine pleuro-pneumonia in Oman yielded strain F38-like mycoplasmas from the lungs in high titre, but no other mycoplasmas: both negative animals had been treated with tylosin shortly before death. Among 21 other lungs examined three of six cases of acute pneumonia yielded Mycoplasma ovipneumoniae; one also yielded M capricolum. M ovipneumoniae was also isolated from all eight cases of chronic pneumonia sampled from an abattoir, and from the lungs of three animals which died without overt signs of pneumonia. A single isolate of M arginini and three of unidentified mycoplasmas were also obtained from goats with and without pneumonia. Various bacterial species were isolated, none of which predominated. Antibodies to M mycoides subspecies capri (M m capri) and strain F38 were detected in sera from eight different sources. Assuming titres of 1 in 40 or more as positive in the indirect haemagglutination test used, 29 per cent of 422 serum samples had antibodies to M m capri alone, 2.6 per cent to strain F38 alone and 3.6 per cent to both organisms. These results confirm the presence of F38-like mycoplasmas in Oman, and indicate also widespread infection with M m capri. The role of the latter in caprine pneumonias in Oman requires elucidation.     

The isolation of multiple strains of Mycoplasma ovipneumoniae from individual pneumonic sheep lungs.

The heterogeneity of Mycoplasma ovipneumoniae isolates from the lungs of sheep with chronic non-progressive pneumonia (CNP) from the same flock raised the possibility that multiple isolates derived from one lung were not all identical. To test this hypothesis, thirty isolates were obtained from each of six pneumonic sheep lungs at slaughter. Four lungs had relatively severe lesions and from each of these, three or four strains of M. ovipneumonia, distinguishable by REA and in most cases by SDS-PAGE, were detected. From the lungs of each of two sheep with mild lesions, two strains of M. ovipneumoniae were detected. Four isolates from one lung were further examined by restriction endonuclease analysis (REA) using many restriction endonucleases. Those which differed with EcoRI also differed when other restriction endonucleases were used. However, partial digests occurred mainly with those restriction endonucleases which recognise cytosine-rich sequences. The presence of multiple strains of one species of microorganism in individual lesions is an unusual concept which may not be limited to one disease or to one host.     

The influence of micro-organisms on the severity of lesions in chronic ovine pneumonia

The degree to which histopathological lesions correlated with the numbers of M. ovipneumoniae and bacteria was studied in sixty 6 to 9 month-old lambs with chronic and subacute pneumonia slaughtered at a local meatworks. Large numbers of M. ovipneumoniae were associated with chronic proliferative changes such as peribronchiolar fibrosis and alveolar interstitial thickening. The combined effect of large numbers of M. ovipneumoniae and bacteria were associated with neutrophilic exudation and epithelial hyperplasia. However, lymphoid hyperplasia and excess mucus production were associated with low bacterial titres. There was no direct correlation between the numbers of M. ovipneumoniae and bacteria present in the pneumonic lungs.     

绵羊支原体肺炎中不同甘露(聚)糖结合凝集素基因型对肺组织病变的影响

为建立不同甘露(聚)糖结合凝集素(MBL)基因型绵羊支原体肺炎的动物疾病模型,本研究选择MBL外显子1中4种不同基因型共32只绵羊作为试验组,6只健康羊作为对照组,在人工感染绵羊肺炎支原体3周后全部迫杀,取肺脏组织做病理切片,以组织病理学评分确定肺部的炎症反应程度.不同MBL型绵羊的肺脏呈现不同程度病理改变,组织病理学评分结果为MBLA型和B型平均分为18.3和19.1,表现为重度病变;MBLD型平均分为12.3,为中度病变;MBL C型平均分为8.9,为轻度病变.本研究以组织病理学评分方法客观量化了不同MBL基因型肺部炎症反应的严重程度,根据评分结果推测MBL A型和B型为易感型,C型为抗性型.本研究利用组织病理学评分方法对其肺炎程度进行量化评价,为筛选绵羊支原体肺炎抗性基因型提供依据.     

The occurrence of mycoplasmas in the lungs of pigs in New Zealand

Attempts were made to recover and serologically identify mycoplasmas from the lungs of 50 pigs with mycoplasmal pneumonia and from 50 lungs without gross evidence of pneumonia. Mycoplasma hyopneumoniae and M. hyorhinis were respectively cultured from 30% and 50% of pneumonic lungs and the former species was also recovered from 12% of non-pneumonic lungs. Three other isolates (one from pneumonic and two from non-pneumonic lungs) differed in colonial morphology from M. hyopneumoniae and M. hyorhinis. The viability of these isolates could not be maintained on subculture and they were not identified serologically. The indirect immunofluorescence test was found to be highly specific for the identification and differentiation of M. hyopneumoniae and M. hyorhinis.     

Immunohistochemical detection of <Emphasis Type="Italic">Mannheimia (Pasteurella) haemolytica</Emphasis> antigens in goats with natural pneumonia

Pneumonia is a leading cause of loss to ruminants throughout the world. Mannheimia (Pasteurella) haemolytica is one of the most important etiological agent of pneumonia in cattle, sheep, and goats. This study was carried out to determine the incidence of M.haemolytica antigens using immunohistochemistry labelling of formalin-fixed, paraffin-embedded tissues in pneumonic lungs of goats slaughtered at abattoir, and then to compare these immunohistochemistry results with the results of bacterial isolation. For these objectives, a total of 1505 goat lungs slaughtered in slaughterhouse were grossly examined and pneumonia was detected in 74 cases (4.91%). Of these, with the exception of verminous pneumonia observed in 32 cases, on 42 pneumonic lungs immunohistochemical examinations were performed. Formalin-fixed and paraffin-embedded lung tissue samples were immunohistochemically stained by the avidin-biotin-peroxidase complex (ABC) procedure using polyclonal antibodies to detect M.haemolytica antigens. Pneumonic lesions were more frequently encountered in cranioventral lobes than caudal lobes, and characterized by irregular lobular foci of atelectasis or lobar pneumonia. The presence of M.haemolytica antigens was detected in 19 (45%) out of 42 pneumonic lungs. Bacterial antigens were found most frequently in the cytoplasm of bronchial and bronchiolar epithelial cells, in the swirling degenerating leukocytes in the alveoli, and in the degenerating leukocytes in the area of coagulation necrosis, less frequently in the epithelial cells of bronchial glands, and lymphoid cells. Conclusionly, immunohistochemical detection of M.haemolytica antigens in pneumonic lungs appear to be more reliable compared to bacterial isolation.     

Isolation and identification of mycoplasmas from the nasal cavity of sheep

Mycoplasmas isolated from the nasal cavity of sheep in a ram test station were examined to determine their identity and prevalence. Specimens were obtained for mycoplasmal culture in 1980, 1982, and 1983 from 558 sheep, and mycoplasmas were isolated from 630 specimens from 320 sheep (57.3%). The isolates were characterized and differentiated into groups on the basis of sensitivity to digitonin, fermentation of glucose, and hydrolysis of arginine. Isolates in some groups were further characterized by use of additional diagnostic media, and their identity was confirmed by agglutination or growth inhibition with antiserum prepared from reference mycoplasmas. Of the 320 sheep with mycoplasmas, 293 had Mycoplasma ovipneumoniae, 12 had M arginini, and 1 had M capricolum. Two sheep had Acholeplasma spp, and 3 sheep had unidentified Mycoplasma spp. The remaining 9 sheep had M ovipneumoniae in combination with Acholeplasma spp (n = 3), M arginini (n = 3), M capricolum (n = 2), and an unidentified Mycoplasma spp (n = 1). The biochemical reactions of the M ovipneumoniae from the 293 sheep were similar, but varied in the degree of growth and fermentation in the basal medium containing glucose. The high prevalence of M ovipneumoniae indicated that it may be commensal in the upper respiratory tract of healthy sheep.     

Examination of the role of Mycoplasma bovis in bovine pneumonia and a mathematical model for its evaluation

The authors screened 34 large cattle herds for the presence of Mycoplasma bovis infection by examining slaughtered cattle for macroscopic lung lesions, by culturing M. bovis from lung lesions and at the same time by testing sera for the presence of antibodies against M. bovis. Among the 595 cattle examined, 33.9% had pneumonic lesions, mycoplasmas were isolated from 59.9% of pneumonic lung samples, and 10.9% of sera from those animals contained antibodies to M. bovis. In 25.2% of the cases M. bovis was isolated from lungs with no macroscopic lesions. The proportion of seropositive herds was 64.7%. The average seropositivity rate of individuals was 11.3% but in certain herds it exceeded 50%. A probability model was developed for examining the relationship among the occurrence of pneumonia, the isolation of M. bovis from the lungs and the presence of M. bovis specific antibodies in sera.     

A microbiological study of pneumonic calf lungs.

BITSCH, V., N. F. FRIIS and H. V. KROGH: A microbiological study of pneumonic calf lungs. Acta vet. scand. 1976, 17, 32–42.–Fifty pneumonic calf lungs were subjected to microbiologic screening with regard to bacteria, mycoplasmas, and viruses.Of bacteria the species most commonly found were Pasteurella multocida (eight lungs), Pasteurella hemolytica (eight lungs), and Corynebacterium pyogenes (13 lungs). Of special interest was the demonstration of Neisseria spp. in five lungs. Mycoplasma dispar was found in 31 lungs, Mycoplasma bovirhinis in 16 lungs, and Urea-plasma in 26 lungs. Cytopathogenic agents were demonstrated in 14 lungs. Four isolates were found to be bovine respiratory syncytial virus, three were bovine viral diarrhea virus, and two were bovine parainfluenza 3 virus. The remaining five cytopathogenic agents were not identified.     

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.     

An abattoir survey of pneumonia and pleuritis in slaughter weight swine from 9 selected herds. II. Enzootic pneumonia of pigs: microbiological findings and their relationship to pathomorphology

Lungs from 191 slaughter pigs with gross lesions indicative of enzootic pneumonia of pigs (EPP) and 80 grossly normal lungs, all originating from 9 different herds, were subjected to microbiological and pathological examinations. The microbiological studies included both bacterial and mycoplasmal culture and also testing for Mycoplasma hyopneumoniae antigen in tissue by indirect immunofluorescent technique. M. hyopneumoniae, Pasteurella multocida and Mycoplasma hyorhinis were detected in 83%, 43% and 37% of the pneumonic lungs, respectively. Mycoplasma flocculare was the most frequently isolated organism in the non-pneumonic lungs. The greatest amounts of macroscopic pneumonia (25.2%) were recorded in lungs with all the three agents M. hyopneumoniae, P. multocida and M. hyorhinis present. The amounts of pneumonia in lungs with M. hyopneumoniae alone and in concurrence with P. multocida, were 9.3% and 15.6%, respectively. M. hyorhinis was also, in this study, associated with higher frequency of diffuse pleuritis. These findings indicate that M. hyorhinis might be involved in the pathogenesis of pneumonia in slaughter pigs. Ninety-six per cent of the isolates of P. multocida from pneumonic lungs could be characterized as type A. In the herds which had the most severe pneumonia problems, toxin production was detected in 83% of the P. multocida strains while only 28% were toxigenic in herds with subclinical to moderate pneumonia problems.     

ISOLATION OF MYCOPLASMA HYOPNEUMONIAE AND ITS ASSOCIATION WITH PNEUMONIA OF PIGS IN AUSTRALIA

Nine strains of mycoplasmas were isolated from the lungs of 5 pigs with clinical signs of naturally acquired enzootic pneumonia. Mycoplasma hyopneumoniae was isolated from the lungs of 1 pig and M. hyorhinis from the lungs of 4. An unidentified mycoplasma, which utilized arginine, grew rapidly in broth culture and produced centred colonies on solid medium, was isolated from the lungs of 4 pigs. The pathogenicity of the isolated strain of M. hyopneumoniae was determined by inoculation of pigs from an enzootic pneumonia-free herd. Enzootic pneumonia was produced in the lungs of all 5 pigs inoculated intranasally and intratracheally with broth cultures of the organism isolatied by limit dilution techniques. Enzootic pneumonia was produced in 3 of 6 pigs inoculated intranasally and intratracheally with M. hyopneumoniae purified by the passage of colonies on agar blocks. M. hyopneumoniae was isolated in pure culture from the lungs of all pigs with induced pneumonic lesions.     

Respiratory infections in housed sheep,with particular reference to mycoplasmas

A commercial housed flock with an annual occurrence of pneumonia was investigated. The organism most commonly isolated from the respiratory tract of lambs up to 6 months old was Mycoplasma ovipneumoniae. Mycoplasma arginini, Mycoplasma conjunctivae, Acholeplasma laidlawii, ureaplasmas and Pasteurella haemolytica biotype A were also isolated: viruses were not isolated, but infection with parainfluenza virus type 3 (P13) was indicated by serology. Colostrum derived antibodies to M. ovipneumoniae and M. arginini declined to minimum levels by 50 days. The development of active immunity to mycoplasmas and P13 virus was associated with an increased incidence of clinical respiratory disease. Histopathological examination of the lungs from 34 lambs showed that 15 had lesions of a proliferative exudative (P.E.) pneumonia, a further 11 showed lymphoid hyperplasia sometimes associated with interstitial thickening, and eight showed no significant pathological changes. Isolations of M. ovipneumoniae were highest from animals with P.E. pneumonia, while M. arginini did not appear to be associated with any specific lung changes. P. haemolytica biotype A was isolated from all cases of P.E. pneumonia. M. ovipneumoniae, M. arginini and P. haemolytica were also isolated from the lower respiratory tract of a proportion of 31 ewes examined post-mortem, but P.E. pneumonia was not observed in these animals.     

互助藏羊肺炎病原绵羊肺炎支原体的PCR检测与分析

青海省互助某羊场藏系绵羊发生肺炎疾病,为了快速准确诊断藏羊肺炎发病的致病病原微生物,及时防控和治疗,采集病死绵羊肺样品,利用PCR分子生物学方法进行鉴定与生物信息学分析。经过分子鉴定,此羊场引发肺病的病原是绵羊肺炎支原体(Mycoplasma ovipneumoniae, MO);测序结果显示样品中鉴定的为同一株病原,鉴定的菌株的16S rRNA基因与参考序列EU265779的同源性达到99.86%。同时遗传进化树显示,鉴定的菌株与GenBank中的绵羊肺炎支原体聚成一大支,其关系最近,在进化角度证实此次鉴定的确实为绵羊肺炎支原体。结果表明,此羊场引发肺炎疾病的病原是绵羊肺炎支原体,提示要对羊群进行相关的病原学研究和流行病学调查,为针对性地对细菌性病原进行对症治疗提供参考。     

An aetiopathological study of chronic bronchopneumonia in lambs in Ireland

Chronic bronchopneumonia in lambs, also known as 'atypical' or 'chronic, non-progressive' pneumonia is a common, frequently sub-clinical disease affecting animals under 12-months-old in intensive production systems. Infection with both Mycoplasma ovipneumoniae and Mannheimia haemolytica have been implicated in the aetiology of this condition and a variety of pulmonary lesions can result. In this study, detailed laboratory examination of 30 abattoir-derived lungs with the characteristic gross features of atypical pneumonia (AP) was carried out with a view to refining and correlating the histopathological and microbiological criteria required for the diagnosis of this disease. For the first time a broad range of laboratory detection techniques including bacterial and virus isolation, fluorescent antibody tests and immunohistochemistry were used in parallel to identify potential causative pathogens such as M. ovipneumoniae, M. haemolytica, parainfluenza type-3 (PI3) virus and respiratory syncytial virus (RSV) in AP lesions. The most consistent finding was the association of gross AP lesions with M. ovipneumoniae, identified by either culture or immunohistochemistry in 27 (90%) of the 30 cases. However the presence M. ovipneumoniae organisms or antigen did not consistently correlate with particular histopathological changes. Furthermore, peri-airway lymphoid hyperplasia, intra-alveolar exudation and nodular 'hyaline scars', which are all previously reported microscopic lesions of AP, were not identified in 12 (40%) of the cases and isolation of M. haemolytica was over-represented in lungs exhibiting suppurative lesions. These findings illustrate the complex aetiopathogenesis of this disease and highlight the requirement to use a combination of diagnostic criteria in its laboratory diagnosis.