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During 1 year, the association between microbiological and pathological findings in 72 lungs from calves submitted to the Danish Veterinary Laboratory for diagnostic purposes was studied. All cases were evaluated pathologically and bacteriologically, whereas only 68 cases were examined for the presence of bovine respiratory syncytial virus (BRSV), parainfluenza-3 virus (PI-3 virus) and bovine coronavirus, 62 cases for bovine viral diarrhoea virus (BVD), 45 cases for bovine adenovirus and 51 cases for mycoplasmas. Based on histopathological examination, the cases were diagnosed as fibrinous and/or necrotizing bronchopneumonia, suppurative bronchopneumonia, embolic pneumonia and others. The diagnoses were based on the dominating and most severe lesions in each lung. Haemophilus somnus, Pasteurella multocida, Actinomyces pyogenes, P. haemolytica and BRSV were the most commonly found bacterial and viral lung pathogens, respectively. Pasteurella spp. and H. somnus were often associated with the more severe fibrinonecrotizing type of bronchopneumonia, whereas BRSV was primarily detected in cases of suppurative bronchopneumonia. Mycoplasma bovis was isolated from one case only, whereas M. dispar, M. bovirhinis and Ureaplasma diversum were present, often concomitantly, in the majority of cases. Aspergillus fumigatus was isolated from one case. U. S.

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Amplified-fragment length polymorphism (AFLP) is a whole-genome fingerprinting method based on selective amplification of restriction fragments. The potential of the method for the characterization of mycoplasmas was investigated in a total of 50 strains of human and animal origin, including Mycoplasma genitalium(n = 11), Mycoplasma pneumoniae(n = 5), Mycoplasma hominis(n = 5), Mycoplasma hyopneumoniae(n = 9), Myco plasma flocculare(n = 5), Mycoplasma hyosynoviae(n = 10), and Mycoplasma dispar(n = 5). AFLP templates were prepared by the digestion of mycoplasmal DNA with BglII and MfeI restriction endonucleases and subsequent ligation of corresponding site-specific adapters. The amplification of AFLP templates with a single set of nonselective primers resulted in reproducible fingerprints of approximately 60 to 80 fragments in the size range of 50 to 500 bp. The method was able to discriminate the analyzed strains at species and intraspecies levels as well. Each of the testedMycoplasma species developed a banding pattern entirely different from those obtained from other species under analysis. Subtle intraspecies genomic differences were detected among strains of all of the Mycoplasma species analyzed. The extent of polymorphism varied markedly between the analyzed mycoplasmas, comprising pattern similarity levels from 61.7% detected among M. disparstrains to 95.9% detected among M. genitalium strains. The results of the present study provide evidence of the high discriminatory power of AFLP analysis, suggesting the possible applicability of this method to the molecular characterization of mycoplasmas.

After an outbreak of mastitis in cattle caused by Mycoplasma bovis a study was made in 5 herds with recent cases (principal herds) and in 4 control herds. In the principal herds, M . bovis was isolated from milk samples, nasal swabs, and from one vaginal swab. M . bovis was also isolated from nasal swabs of calves in 2 of the 4 control herds, whereas all milk samples and vaginal swabs from the control herds were negative.Evaluation of serum antibody titres to M . bovis among non-mastitic animals of 3 principal herds and 1 control herd showed no difference in distribution of the titre values, which generally were low. However, cows excreting M . bovis in the milk had high antibody titres. The way of introduction to the herds and the spread of the infection within the herds could not be established by the study, which was supplemented by a DNA restriction fragment analysis of a number of M . bovis isolates. IntroductionMycoplasma bowis infection in cattle was diagnosed for the first time in Denmark in November 1981. M . bowis was isolated from pneumonic lesions in a calf (FRIIS, 1984) and since then, it has been found sporadically in pneumonic calf lungs.The first cases of mastitis in Denmark caused by M . bowis were diagnosed in the spring of 1984. About 100 cows from 14 herds within a small geographic area were affected, Apart from a few sporadic cases, later outbreaks were also clustered within restricted geographic areas.Until now, M. bowis is the only mycoplasma species found as a cause of mastitis in Denmark. In order to study the epidemiological aspects of the infection, a field study of the most recent outbreaks was carried out. The aims were: 1 . To examine the occurrence of M . bowis in herds with and without diagnosed M . bowis mastitis, 2. To study how M. bowis was introduced into the herds, and 3. How M . bowis had spread within the infected herds. Starting in January, 1986, M . bovis mastitis had been diagnosed in 57 cows from 16 different herds in the same district. In cooperation with the local practising veterinarians, 5 herds with recent cases of M . bovis mastitis (principal herds) were selected for the study. Four control herds from the same area, without diagnosed cases of M . bovis mastitis, but comparable to the M . bovis mastitis herds concerning housing, supplementation, and management, were chosen as control herds. U.S. C o p y q h t Clearance Cenrer Code Statement: 0931 -1793/91/3803 -0195$02.50/0 Material and Methods