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In clinical trials OCT plays

In clinical trials, OCT plays a major role for quantitative measurement of retinal thickness. OCT retinal thickness measurements are important in defining inclusion and exclusion criteria in clinical studies (e.g., foveal thickness of more than 250 or 300μm for studies of macular edema). OCT retinal thickness measurements are important in guiding treatment and re-treatment during clinical trials (e.g., retreat if there is more than 100μm increase in retinal thickness in neovascular AMD).

Evaluation of artifacts among various oct machines
To evaluate artifact errors, Giani et al. obtained error frequency (EF-exam), which was calculated as the percentage of OCT examinations that included at least one B-scan with an artifactual error. To account for the different number of scan lines and variable B-scan density of each instrument, the absolute number of errors produced by each instrument was recorded, and the ratio of total number of errors per total number of B-scans for each machine was calculated (EF-scan).

Artifacts based on pathology
Studies by various authors have shown that the severity of retinal abnormalities is directly connected to the frequency of imaging errors. Giani et al. proposed that this could occur because the software tries to identify the normal pattern of hyper- and hypo-reflective layers on each single A-scan. Pathologic conditions lead to haphazard remodeling of the retinal segmentation that is strictly dependent on the severity and the type of alteration. They observed, however, that the errors produced by different instruments were often similar in certain pathologic conditions. They inferred that it myosin was likely because for all the devices, different layers were recognized using algorithms that identified gray value variations along the A-scan lines.
Giani et al. observed that in the epiretinal membrane group, errors were more frequent in the non-central macula and in delimiting the inner retinal boundary. In neovascular and nonneovascular AMD groups, however, the errors affecting the outer retinal boundary were more common. They also reported that in the macular hole group, the most common error was the imprecise recognition of hole shape, leading to overestimation of retinal thickness in the outer layers adjacent to the hole center. In severe myopia, they noted that the most common error was the translation of the retinal boundary adjacent to the choroid. The authors explained that this observation is occurring as a result of the significant reduction of retinal layer reflectivity and thickness typical of this condition. The signal from the choroid was increased because of the reduced attenuation of the retina and this resulted in shifting of the boundary positions by the software toward the choroidal hyper reflectivity.
Han et al. reported that for both instruments, eyes with uveitis had the highest percentage of scans with centration errors. This result may be related to media opacity creating a difficult view for the OCT operator to center the scan properly in uveitic eyes. They also observed that in eyes with AMD, misidentifications of the outer retina were more common than misidentification of the inner retina for both CIRRUS (Carl Zeiss Meditec, Dublin, CA) and SPECTRALIS (Heidelberg Engineering, Vista, CA). They inferred that this is likely due to pathologic disruptions of the outer retina such as drusen and choroidal neovascularization, which creates challenges for proper appropriate outer segmentation line placement. Kim et al. also reported a higher rate of segmentation error in AMD, more in CIRRUS HD-OCT (Carl Zeiss Meditec, Dublin, CA) compared to SPECTRALIS (Heidelberg Engineering, Vista, CA) OCT.
To conclude, artifacts occur in all makes of OCT machines and the first step to rectify these artifacts is by identifying them. This can be done by looking at the topography map, which would enable us to identify off-center artifacts. Similarly, screening of individual scans helps us to identify improper delineation of inner and outer retinal layers and out of register artifacts. Looking at the rendered fundus image helps us to note motion and blink artifacts. The next step would be to take the appropriate remedial measures to achieve more realistic information from this imaging technique. (Table 1) At the end, not all the artifacts are important and affect the clinical management. The hope is that future advancement in OCT technology would further reduce artifacts to improve the image quality and clinical management.

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.