A mycobacterial growth inhibition assay (MGIA) for bovine TB vaccine development

Human tuberculosis remains a significant cause of mortality and morbidity throughout the world. The global economic impact of bovine TB is considerable. An effective vaccine would be the most cost-effective way to control both epidemics, particularly in emerging economies. TB vaccine research would benefit from the identification of an immune correlate of protection with which vaccines could be gated at both preclinical and clinical levels. In-vitro mycobacterial growth inhibition assays (MGIA) are functional assays that include most aspects of the complex host immune response to mycobacteria, and they may serve as functional immune correlates for vaccine development. We applied to cattle an MGIA that was developed for use with human and murine samples. Several technical difficulties were encountered while transferring it to the cattle model. However, our data demonstrate that the assay was not discriminatory in cattle and further work is needed before using it for bovine TB vaccine development

Tuberculin skin testing boosts interferon gamma responses to DIVA reagents in Mycobacterium bovis-Infected cattle

ABSTRACT Mycobacterium bovis BCG vaccination sensitizes cattle to bovine tuberculin, which compromises the use of the current bovine tuberculosis (TB) surveillance tests. Although the performance of a blood test (that utilizes antigens expressed by Mycobacterium bovis but not by BCG) capable of discriminating infected from vaccinated animals (DIVA interferon gamma test [DIT]) has been evaluated in naturally infected TB field reactors, there is a need to perform similar analysis in a BCG-vaccinated M. bovis -infected population. Furthermore, we explored different scenarios under which a DIT may be implemented alongside BCG vaccination: (i) serial testing to resolve potential false-positive skin test results or (ii) a standalone test to replace the single intradermal comparative cervical tuberculin (SICCT) skin test. Our results demonstrated significantly better relative test sensitivity when the DIT was evaluated in a serial test scenario. Direct comparison of pre- and post-skin test blood samples revealed that the SICCT test induced significant boosting of the gamma interferon response in M. bovis -infected animals to both the ESAT-6–CFP-10 and Rv3615c peptide cocktails that comprise the DIT, which persisted for the ESAT-6–CFP-10 reagent for at least 14 days. Importantly, no similar boosting effects were observed in noninfected BCG vaccinates, suggesting that DIVA blood testing after a recent skin test would have minimal impact on test specificity. </jats:p

Compendium of Climate-smart Agriculture Technologies and Practices

Nepal is a vulnerable country to the impacts of climate change. The adverse effects of climate change have decreased agricultural production and productivity. Therefore, technologies and strategies to develop resilience agriculture and increased agriculture productivity are urgently needed to create climate-smart technologies and help the existing technologies to adapt to climate change. This compendium presents climate-smart agriculture (CSA) technologies and interventions for enhancing food security with adaptation and mitigation as co-benefits. CSA involves smart farming practices and strategies that help develop resilience agriculture, increase crop and livestock productivity, reduce greenhouse gas emissions, and enhance food security goals. This compendium has been developed for extension workers to support up-scaling climate-smart technologies and build climate resilience villages that enhance food, nutrition, and income, mainly for marginal communities striving in marginal areas

Experimental infection of cattle with Mycobacterium tuberculosis isolates shows the attenuation of the human tubercle bacillus for cattle

The Mycobacterium tuberculosis complex (MTBC) is the collective term given to the group of bacteria that cause tuberculosis (TB) in mammals. It has been reported that M. tuberculosis H37Rv, a standard reference MTBC strain, is attenuated in cattle compared to Mycobacterium bovis. However, as M. tuberculosis H37Rv was isolated in the early 1930s, and genetic variants are known to exist, we sought to revisit this question of attenuation of M. tuberculosis for cattle by performing a bovine experimental infection with a recent M. tuberculosis isolate. Here we report infection of cattle using M. bovis AF2122/97, M. tuberculosis H37Rv, and M. tuberculosis BTB1558, the latter isolated in 2008 during a TB surveillance project in Ethiopian cattle. We show that both M. tuberculosis strains caused reduced gross and histopathology in cattle compared to M. bovis. Using M. tuberculosis H37Rv and M. bovis AF2122/97 as the extremes in terms of infection outcome, we used RNA-Seq analysis to explore differences in the peripheral response to infection as a route to identify biomarkers of progressive disease in contrast to a more quiescent, latent infection. Our work shows the attenuation of M. tuberculosis strains for cattle, and emphasizes the potential of the bovine model as a ‘One Health’ approach to inform human TB biomarker development and post-exposure vaccine development

Potential for rapid antibody detection to identify tuberculous cattle with non-reactive tuberculin skin test results

Abstract Background Bovine tuberculosis (TB) control programs generally rely on the tuberculin skin test (TST) for ante-mortem detection of Mycobacterium bovis-infected cattle. Results Present findings demonstrate that a rapid antibody test based on Dual-Path Platform (DPP®) technology, when applied 1-3 weeks after TST, detected 9 of 11 and 34 of 52 TST non-reactive yet M. bovis-infected cattle from the US and GB, respectively. The specificity of the assay ranged from 98.9% (n = 92, US) to 96.0% (n = 50, GB) with samples from TB-free herds. Multi-antigen print immunoassay (MAPIA) revealed the presence of antibodies to multiple antigens of M. bovis in sera from TST non-reactors diagnosed with TB. Conclusions Thus, use of serologic assays in series with TST can identify a significant number of TST non-reactive tuberculous cattle for more efficient removal from TB-affected herds

Metabolic phenotype of bovine tuberculosis field strains

Whilst the whole genome sequences of M tuberculosis H37 Rv, M bovis AF6112122/97 and BCG have been published and detailed genetic analysis of differences between Mycobacterium tuberculosis complex (MTBC) strains have been explored, little of this knowledge has been related to phenotypes. The current study employs the high throughput metabolic assay Biolog Phenotype MicroArray (PM) technology has been used for the first time to examine phenotypic differences in slow growing mycobacteria. Two established methods MTT (Tetrazolium dye) and Oxygen Electrode (Measuring oxygen consumption) were used to validate PM technology and previous studies on metabolism of mycobacteria using these existing methods were reviewed to put the current work into context. For PM technology to be useful background reading had to be taken into account. Systematic investigations of dye reduction and starvation revealed that a 24 hour starvation step succeeded in diminishing background dye reduction. Utilisation of carbon substrates by M tuberculosis H37 Rv was significantly different to M bovis type 9 strains. M tuberculosis H37 Rv used 7 substrates not used by M bovis AF6112122/97 while M bovis AF6112122/97 used 4 substrates not used by M tuberculosis H37 Rv. Interestingly, a few differences were also observed within type 9 strain panel which showed the utilisation of Tween 80, Monomethyl succinate, Glycerol and D-malate to be significant different between the strains in the panel. Although metabolism of known nitrogen sources such as L-alanine and D-serine were confirmed by MTBC strains, utilisation of many amino acids for which auxotrophs have been obtained for M tuberculosis H37 Rv was not shown in this work. These data suggest a requirement for, and indeed may assist in the optimisation of the PM technology for MTBC. This work represents the first step in using PM technology to provide applied, practical information that can be implemented in the diagnostic arena, principally in facilitating the improvement of current media to ensure good growth of all strains

Abuse of older adults before moving to old age homes in Pokhara Lekhnath Metropolitan City, Nepal: A cross-sectional study.

IntroductionThe number of older individuals relocating from their homes to old age homes is increasing in Nepal. This study was conducted to assess the reasons why older people chose to move to old age homes, the status and forms of abuse they experienced, and the risk factors associated with their abuse before moving to old age homes.Materials and methodsThis study was a cross sectional study conducted among older adults currently residing in all the old age homes of Pokhara Lekhnath Metropolitan City. Complete enumeration of the respondents was done and data was collected consecutively, using a semi-structured interview schedule, from all older adults aged 60 years and above who had been living in the homes for at least a month. The total sample size was 109. The collected data was analyzed using descriptive statistics and binary logistic regression was used as an inferential statistics to determine the predictors of abuse.ResultsA majority of the respondents (56.0%) came to old age homes on their own volition, 24.7% reported that they came to the homes because they were physically weak and they had no one to care for them at their residence, while 11% reported that they were forcefully sent by their caregivers. Out of total respondents, 60.6% reported that they experienced some form of abuse before they came to the old age home: most frequent was caregiver neglect (34.9%) and verbal abuse (34.9%), while few experienced financial abuse (2.8%). Women were at a higher risk of abuse than men (pConclusionsA majority of the older adults who transferred to old age homes in Pokhara Lekhnath Metropolitan city had been earlier abused by their caregivers, mainly through neglect and verbal abuse, and women were at a higher risk for abuse than men

BCG δzmp1 vaccine induces enhanced antigen specific immune responses in cattle

Mycobacterium bovis (M. bovis) causes major economy and public health problem in numerous countries. In Great Britain, despite the use of a test-and-slaughter strategy, the incidence of bovine tuberculosis (bTB) in cattle has steadily risen in recent years. One strategy being considered to reduce the burden of bTB in cattle is the development of an efficient vaccine. The only current potentially available vaccine against tuberculosis, live attenuated M. bovis bacille Calmette-Guérin (BCG), has demonstrated variable efficacy in both humans and cattle and the development of improved vaccination strategies for cattle is a research priority. In this study we assessed the immunogenicity in cattle of two recombinant BCG strains, namely BCG Pasteur Δzmp1::aph and BCG Danish Δzmp1. By applying a recently defined predictive immune-correlate of protection (T cell memory responses measured by cultured ELISPOT), we have compared these two recombinant BCG with wild-type BCG Danish SSI. Our results demonstrated that both strains induced superior T cell memory responses compared to wild-type BCG. These data provide support for the prioritisation of testing BCG Danish Δzmp1 in vaccination/M. bovis challenge studies to determine its protective efficacy

Cluster analysis of <i>M. tuberculosis</i> complex strains using Biolog PM data

<p>. Each replicate inoculum is displayed with its coordinates in the 3 major dimensions, rotated to display groupings. Coding, including colour, is explained in the list of strains used in this study (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0052673#pone-0052673-t001" target="_blank">Table 1</a>).</p