SUMMARYThree strains of M. gallisepticum comprising S6 of low passage (virulent), S6 of high passage and A514 of high passage in artificial media and one M. gallinarum strain of high passage, were inoculated into 18-day-old chick embryos. Four groups of infected chicks hatched, one corresponding to each mycoplasma strain; these were investigated during the first 28 days of life and again for a period in lay. During the first 28 days of life, the virulent S6 strain was recovered more frequently from a wider variety of tissues for a longer time than were the other two strains of M. gallisepticum; this strain also produced more severe clinical disease including nervous signs, respiratory lesions and swollen hocks. Although nervous signs were confined to birds infected with the virulent S6, both S6 strains were isolated from brains and hocks, suggesting this strain's proclivity for these sites. One A514 infected chick developed unilateral eye enlargement from which mycoplasma were isolated. All strains of mycoplasma were isolated from respiratory tissues, indicating a proclivity common to all. Recoveries of mycoplasma were often associated with signs and/or lesions but not always, and recoveries also occurred in the absence of signs and lesions.M. gallinarum caused no clinical signs or lesions in young chicks and was rarely isolated. In mature birds, mycoplasma were isolated from the respiratory tissues of some infected with either of the two S6 strains or with M. gallinarum, but not from A514 infected chickens. In both younger and mature chickens, mycoplasma were most likely to be recovered from respiratory tissues and the infra-orbital sinus. Most chicks infected with the virulent S6, showed positive haemagglutination inhibition (HAI) reactions from 4 days of age which preceded the rapid serum agglutination (RSA) reactions. In contrast, chicks infected with other strains of M. gallisepticum either showed no positive HAI reactions, or Judith Varley and F.T.W. Jordan developed them after 21 days. In either case, positive RSA preceded HAI reactions. The numbers of mature birds examined were small, but, comparing isolation of M. gallisepticum with serological results, it appears that false positives occur with the RSA and both false positives and negatives with the HAI test. No egg transmission of mycoplasma was observed. INTRODUCTIONIn a previous paper, Power and Jordan (1976a) used three strains of M. gallisepticum and one strain of M. gallinarum and showed they differed in virulence as assessed by mortality in chicks and turkey poults. This present paper describes a sequel experiment in which the same four strains of mycoplasma were used to infect chicks under similar conditions in order to examine effects other than mortality. Clinical signs, gross lesions and the distribution and persistence of mycoplasma in a wide variety of tissues together with serological results, were recorded in chicks at specified intervals after infection.
SUMMARYDucklings on a problem farm which showed persistent and unacceptably high mortality yielded a larger range and greater number of viruses than did ducklings from a second flock, in which mortality was of a power and acceptable level.
SUMMARYIn turkey poults aged up to 28 days, a virulent S6 strain of Af. gallisepticum was recovered more frequently from more tissues for a longer time than were other strains. The virulent strain caused nervous signs and gross brain lesions in poults, and was often isolated from the brain, suggesting its neurotropism. All M. Gallisepticum strains were isolated from the synovial fluid of hocks, but swollen hocks and foot pads were seen only in poults infected with the A514 strain. It would seem, therefore, that although proclivity for joints was shown by all strains, only A514 produced grossly pathogenic effects in these young birds. All strains of Af. gallisepticum showed some proclivity for respiratory tissues. Signs, gross lesions and recoveries of mycoplasma frequently failed to correlate. Perosis was seen in only two poults; these were infected with M. gallinarum with which the condition may, or may not, be associated. Serological reactions to both the rapid serum agglutination and haemagglutination inhibition tests developed in the 3rd and 4th weeks of life in all poults infected with Af. gallisepticum strains although false positives and negatives were recorded.The main results of infection with the strains in turkey poults and in a similar study in chicks are summarised. INTRODUCTIONIn a previous paper, Power and Jordan (1976) used three strains of M. gallisepticum and one strain of M. gallinarum and showed they differed in virulence as assessed by mortality in chicks and turkey poults. This present paper describes a sequel experiment in which the same four strains of mycoplasma were used to infect turkey poults under similar conditions in order to examine effects other than mortality. Clinical signs, gross lesions and the distribution and persistence of mycoplasma in a wide variety of tissues, together with serological results, were recorded in turkey poults at specified intervals after infection.
The proteins of seven Bordetella bronchiseptica-like isolates were examined by polyacrylamide gel electrophoresis (PAGE). They were compared with three similar isolates from overseas, one of which is the type strain of Bordetella avium, and with Bordetella bronchiseptica NCTC 452T and Alcaligenes faecalis NCTC 415. Apart from Alcaligenes faecalis, there was strong homology between the isolates suggesting their close relationship, but minor differences were apparent, too. The significance of these is uncertain.
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