Tag Archives: myosin

The unexpected survival of control

The unexpected survival of control group cattle could also be related to the effects of the ECF vaccination administered to all cattle before the trial. Given that both MCF and ECF are associated with the proliferation of T-cells (Dewals et al., 2008; Kessy and Matovelo, 2009; Thonur et al., 2006) any non-specific suppression of T-cell proliferation as a consequence of ECF vaccination could provide some protection from MCF pathogenesis. This myosin will be investigated in a subsequent field trial.
We also assessed FliC as an adjuvant. The in-vitro analysis showed that FliC stimulation of bovine TLR5 induced a significant CXCL-8 response in HEK cells, although this was lower than that induced via human TLR5. The addition of FliC to the myosin vaccine formulation (Groups 2 & 3) reduced antibody titres and survival when compared with Group 1, although this latter effect was just outside the conventional levels of significance (p=0.06). These data suggest that FliC is unlikely to enhance protection against MCF.
WA-MCF has a case-fatality ratio greater than 96% (Plowright et al., 1960). The finding that 15% of the trial cattle had evidence of prior AlHV-1 infection was therefore surprising. Non-fatal infections have been reported in SA-MCF (Moore et al., 2010; Otter et al., 2002) and serological evidence of non-fatal infections was described in the field trial (Lankester et al., 2016). These findings add further evidence that non-fatal outcomes are a feature of WA-MCF and that the case-fatality ratio could be lower than previously described.
In summary, immunization with atAlHV-1 induces an oro-nasopharyngeal antibody response in FH and SZC and there is evidence that, when combined with Emulsigen®, the vaccine mixture induces a partial protective immunity in SZC. A larger study is required to better quantify this effect. We have shown that direct challenge with the pathogenic AlHV-1 virus is effective at inducing MCF in SZC. We have also provided evidence that the atAlHV-1+Emulsigen® formulation may be less effective at stimulating a protective immune response in SZC cattle than FH cattle. Furthermore, and in support of the field trial, we have provided evidence that non-fatal AlHV-1 infections are relatively common and we speculate that there could be resistance to fatal MCF in SZC cattle, possibly through genetic background, previous (sub-clinical) exposure to AlHV-1 or alternative acquisition of a level of inherent immunity. Finally, we demonstrated that FliC is not an appropriate adjuvant for the atAlHV-1 vaccine.

Acknowledgements
We are grateful for the cooperation of the Simanjiro Development Trust, Dr. Moses Ole-Neselle and the people of Emboreet Village for their cooperation, and to the staff at the Nelson Mandela African Institution for Science and Technology (Arusha, Tanzania) and the Moredun Research Institute (Midlothian, UK) for access to laboratory facilities and equipment and for their time spent processing samples. This work was supported by the Scottish Government, the Department for International Development and the Biotechnology and Biological Sciences Research Council under the CIDLID initiative (Control of Infectious Diseases of Livestock for International Development); grants BB/H009116/1, BB/H008950/1 and BB/H009302/1.

Introduction
Mycoplasma iowae (MI) is one of the four pathogenic mycoplasma species in poultry. MI is mainly pathogenic to turkey. According to the United States Animal Health Association report in 2012 and 2013, MI has been listed as one of the important disease problems affecting the commercial turkey population (Helm, 2013, 2012). Vertical transmission from breeders to their progeny is a common route of MI infection (Wood and Wilson, 2013); this results in many commercial implications between breeders, hatcheries, and commercial growers. Therefore, major turkey breeders are calling for enforcing effective eradication programs (Kenyon, 2015). Intraspecific identification is essential for outbreak investigation and identifying the source of infection, which is in turn very important for prevention, control and eradication efforts. Molecular assays are the main tools by which we can identify and differentiate between MI strains, isolates and clinical cases. For epidemiological investigation of avian mycoplasma, there are two main molecular methods for differentiating between strains of the same species; DNA finger printing and sequence typing. Zhao and Yamamoto (1989) successfully used Restriction Fragment Length Polymorphism (RFLP) assay to differentiate between MI strains. Then, Fan et al. (1995) described Random Amplified Polymorphic DNA (RAPD) for all four pathogenic avian mycoplasma. For most fingerprinting assays, low reproducibility is a weakness, making it difficult to compare results from different laboratories. Additionally, they require isolation of the organism in a pure culture, which is not always successful in clinical cases due to the fastidious nature of avian mycoplasma. Therefore, sequence typing is a favored method for intraspecific identification of avian mycoplasma. Multiple sequence typing assays have been developed for strain differentiation of Mycoplasma gallisepticum (MG) and Mycoplasma synoviae (MS), two major avian mycoplasma pathogens (El-Gazzar et al., 2012; Ferguson et al., 2005 Ferguson et al., 2005). These assays have successfully been used to investigate MG and MS outbreaks (El Gazzar et al., 2011). However, there are no available sequence typing assays for MI. The purpose of this study was to develop a Multilocus Sequence Typing (MLST) assay and to examine its potential use for MI sequence typing.