Contagious Bovine Pleuropneumonia: A Comprehensive Overview

Contagious Bovine Pleuropneumonia: Global Eradication Remains a Challenging and Distant Goal

Contagious bovine pleuropneumonia (CBPP) is one of the six high impact diseases for which currently World Organization for Animal Health (WOAH) has established an official procedure for recognition of disease-free status for trade purposes. Although its exact distribution, incidence, and impact have not been well established, the disease is known to be endemic in sub-Saharan Africa, where it has a severe socio-economic impact on people's livelihoods. Control or elimination of the disease can be achieved by various strategies including vaccination, movement control, and stamping-out. Due to many factors, countries in sub-Saharan Africa are still struggling with this disease, compromising continental and global eradication. In this review, basic epidemiologic features and clinical signs of CBPP are presented and disease control challenges, particularly in endemic countries, are briefly discussed.

A candidate competitive ELISA based on monoclonal antibody 3A8 for diagnosis of contagious bovine pleuropneumonia

For the development of a competitive ELISA (cELISA) to detect serum antibodies against the Mycoplasma mycoides subsp. Mycoides (Mmm) (strain PG1), the causative agent of contagious bovine pleuropneumonia (CBPP), all the proteins of this pathogen were analyzed. Then, a specific extracellular region of a transmembrane protein with the potential for diagnosis was identified. After that, a monoclonal antibody (Mab) named 3A8 was obtained using this extracellular region as an immunogen. Finally, a cELISA was established with the extracellular domain of this transmembrane protein as the coating antigen, Mab 3A8 as the competitive antibody, and HRP-labeled goat anti-mouse IgG as the enzyme-labeled antibody. This established method was used to detect the antibody dynamic regularity of goats which are artificially immunized Mmm and was also compared with a commercial ELISA kit. Further, the sera of 1011 different cattle from border provinces of China were monitored using a candidate Mab 3A8 cELISA. The detection results of known background sera used in this study indicate that a candidate diagnostic marker was successfully identified by analyzing all the coding proteins of Mmm in this research, and the cELISA established based on the Mab 3A8 against this protein can detect CBPP-positive serum with specificity and has no cross-reaction with other related epidemic disease-positive sera. In addition, we tested the sera collected from the border areas of China using the established ELISA, and no positive sample was detected. The research protocol of the CBPP cELISA established in this study is different from the traditional method, which can greatly reduce the investment of manpower and capital and save development time. We believe that this study's protocol could serve as a reference for the development of detection methods for mycoplasma and other complex pathogens. KEY POINTS: • A Mmm-specific diagnostic marker was obtained based on protein characteristics. • A cELISA was established for CBPP serum antibody detection. • The serological investigation was conducted for CBPP in the border areas of China.

Comparative Proteomic Analysis of Secretory Proteins of Mycoplasma bovis and Mycoplasma mycoides subsp. mycoides Investigates Virulence and Discovers Important Diagnostic Biomarkers

The most important pathogenic Mycoplasma species in bovines are Mycoplasma bovis (M. bovis) and Mycoplasma mycoides subsp. mycoides (Mmm). Mmm causes contagious bovine pleuropneumonia (CBPP), which is a severe respiratory disease widespread in sub-Saharan Africa but eradicated in several countries, including China. M. bovis is an important cause of the bovine respiratory disease complex (BRD), characterized worldwide by pneumonia, arthritis, and mastitis. Secreted proteins of bacteria are generally considered virulence factors because they can act as toxins, adhesins, and virulent enzymes in infection. Therefore, this study performed a comparative proteomic analysis of the secreted proteins of M. bovis and Mmm in order to find some virulence-related factors as well as discover differential diagnostic biomarkers for these bovine mycoplasmas. The secretome was extracted from both species, and liquid chromatography-tandem mass spectrometry was used, which revealed 55 unique secreted proteins of M. bovis, 44 unique secreted proteins of Mmm, and 4 homologous proteins. In the M. bovis secretome, 19 proteins were predicted to be virulence factors, while 4 putative virulence factors were identified in the Mmm secretome. In addition, five unique secreted proteins of Mmm were expressed and purified, and their antigenicity was confirmed by Western blotting assay and indirect ELISA. Among them, Ts1133 and Ts0085 were verified as potential candidates for distinguishing Mmm infection from M. bovis infection.

Genome Editing of Veterinary Relevant Mycoplasmas Using a CRISPR-Cas Base Editor System

Mycoplasmas are minimal bacteria that infect humans, wildlife, and most economically relevant livestock species. Mycoplasma infections cause a large range of chronic inflammatory diseases, eventually leading to death in some animals. Due to the lack of efficient recombination and genome engineering tools for most species, the production of mutant strains for the identification of virulence factors and the development of improved vaccine strains is limited. Here, we demonstrate the adaptation of an efficient Cas9-Base Editor system to introduce targeted mutations into three major pathogenic species that span the phylogenetic diversity of these bacteria: the avian pathogen Mycoplasma gallisepticum and the two most important bovine mycoplasmas, Mycoplasma bovis and Mycoplasma mycoides subsp. mycoides. As a proof of concept, we successfully used an inducible SpdCas9-pmcDA1 cytosine deaminase system to disrupt several major virulence factors in these pathogens. Various induction times and inducer concentrations were evaluated to optimize editing efficiency. The optimized system was powerful enough to disrupt 54 of 55 insertion sequence transposases in a single experiment. Whole-genome sequencing of the edited strains showed that off-target mutations were limited, suggesting that most variations detected in the edited genomes are Cas9-independent. This effective, rapid, and easy-to-use genetic tool opens a new avenue for the study of these important animal pathogens and likely the entire class Mollicutes.

IMPORTANCE Mycoplasmas are minimal pathogenic bacteria that infect a wide range of hosts, including humans, livestock, and wild animals. Major pathogenic species cause acute to chronic infections involving still poorly characterized virulence factors. The lack of precise genome editing tools has hampered functional studies of many species, leaving multiple questions about the molecular basis of their pathogenicity unanswered. Here, we demonstrate the adaptation of a CRISPR-derived base editor for three major pathogenic species: Mycoplasma gallisepticum, Mycoplasma bovis, and Mycoplasma mycoides subsp. mycoides. Several virulence factors were successfully targeted, and we were able to edit up to 54 target sites in a single step. The availability of this efficient and easy-to-use genetic tool will greatly facilitate functional studies of these economically important bacteria.

Mycoplasmas as Host Pantropic and Specific Pathogens: Clinical Implications, Gene Transfer, Virulence Factors, and Future Perspectives

Mycoplasmas as economically important and pantropic pathogens can cause similar clinical diseases in different hosts by eluding host defense and establishing their niches despite their limited metabolic capacities. Besides, enormous undiscovered virulence has a fundamental role in the pathogenesis of pathogenic mycoplasmas. On the other hand, they are host-specific pathogens with some highly pathogenic members that can colonize a vast number of habitats. Reshuffling mycoplasmas genetic information and evolving rapidly is a way to avoid their host's immune system. However, currently, only a few control measures exist against some mycoplasmosis which are far from satisfaction. This review aimed to provide an updated insight into the state of mycoplasmas as pathogens by summarizing and analyzing the comprehensive progress, current challenge, and future perspectives of mycoplasmas. It covers clinical implications of mycoplasmas in humans and domestic and wild animals, virulence-related factors, the process of gene transfer and its crucial prospects, the current application and future perspectives of nanotechnology for diagnosing and curing mycoplasmosis, Mycoplasma vaccination, and protective immunity. Several questions remain unanswered and are recommended to pay close attention to. The findings would be helpful to develop new strategies for basic and applied research on mycoplasmas and facilitate the control of mycoplasmosis for humans and various species of animals.

Development and Evaluation of a Combined Contagious Bovine Pleuropneumonia (CBPP) and Lumpy Skin Disease (LSD) Live Vaccine

Mycoplasma mycoides subsp. mycoides (Mmm) is the causative agent of contagious bovine pleuropneumonia (CBPP). Lumpy skin disease (LSD) is a viral disease of cattle caused by lumpy skin disease virus (LSDV). LSD and CBPP are both transboundary diseases spreading in the same areas of Africa and Asia. A combination vaccine to control CBPP and LSD offers significant value to small-scale livestock keepers as a single administration. Access to a bivalent vaccine may improve vaccination rates for both pathogens. In the present study, we evaluated the LSDV/CBPP live combined vaccine by testing the generation of virus neutralizing antibodies, immunogenicity, and safety on target species. In-vitro assessment of the Mycoplasma effect on LSDV growth in cell culture was evaluated by infectious virus titration and qPCR during 3 serial passages, whereas in-vivo interference was assessed through the antibody response to vaccination. This combined Mmm/LSDV vaccine could be used to protect cattle against both diseases with a single vaccination in the endemic countries. There were no adverse reactions detected in this study and inoculated cattle produced high levels of specific antibodies starting from day 7 post-vaccination, suggesting that this combination vaccine is both safe and effective.

DETECTION OF MYCOPLASMA AND CHLAMYDIA IN PYTHONS WITH AND WITHOUT SERPENTOVIRUS INFECTION

Serpentoviruses (order Nidovirales) are an important cause of respiratory disease in snakes. Although transmission studies have shown that serpentoviruses can cause respiratory disease in pythons, the possible role of additional potential pathogens is not yet understood. Very little information is available on the role of mycoplasma and chlamydia infections in disease in pythons. Diagnostic samples from 271 pythons of different genera submitted to a laboratory for detection of serpentoviruses were also screened for mycoplasma and chlamydia infections by PCR. Most of the samples were oral swabs. Almost 30% of the samples were positive for serpentoviruses, and mycoplasmas were detected in more than 60% of the pythons. The occurrence of these two pathogens correlated significantly (P < 0.001). Additionally, about 3% of the snakes tested positive for Chlamydia. This study found a high prevalence of mycoplasmas in the tested pythons and a correlation between infections with these bacteria and serpentoviruses in python samples submitted for diagnostic testing. Because the role mycoplasmas play in respiratory diseases of snakes is still largely unknown, further investigations are necessary to evaluate the role of mixed infections in disease.

Assessment of the control measures for category A diseases of Animal Health Law: Contagious Bovine Pleuropneumonia

EFSA received a mandate from the European Commission to assess the effectiveness of some of the control measures against diseases included in the Category A list according to Regulation (EU) 2016/429 on transmissible animal diseases ('Animal Health Law'). This opinion belongs to a series of opinions where these control measures will be assessed, with this opinion covering the assessment of control measures for Contagious Bovine Pleuropneumonia (CBPP). In this opinion, EFSA and the AHAW Panel of experts review the effectiveness of: (i) clinical and laboratory sampling procedures, (ii) monitoring period, (iii) the minimum radius of the protection and surveillance zones, and (iv) the minimum length of time the measures should be applied in these zones. The general methodology used for this series of opinions has been published elsewhere. Several scenarios for which these control measures had to be assessed were designed and agreed prior to the start of the assessment. Different clinical and laboratory sampling procedures are proposed depending on the scenarios considered. The monitoring period of 45 days was assessed as not effective and at least 90 days (3 months) is recommended in affected areas where high awareness is expected; when the index case occurs in an area where the awareness is low the monitoring period should be at least 180 days (6 months). Since transmission kernels do not exist and data to estimate transmission kernels are not available, the effectiveness of surveillance and protection zones for CBPP was based on expert knowledge. A surveillance zone of 3 km was considered effective, while a protection zone including establishments adjacent to affected ones is recommended. Recommendations, provided for each of the scenarios assessed, aim to support the European Commission in the drafting of further pieces of legislation, as well as for plausible ad hoc requests in relation to CBPP.

Minimalistic mycoplasmas harbor different functional toxin-antitoxin systems

Mycoplasmas are minute bacteria controlled by very small genomes ranging from 0.6 to 1.4 Mbp. They encompass several important medical and veterinary pathogens that are often associated with a wide range of chronic diseases. The long persistence of mycoplasma cells in their hosts can exacerbate the spread of antimicrobial resistance observed for many species. However, the nature of the virulence factors driving this phenomenon in mycoplasmas is still unclear. Toxin-antitoxin systems (TA systems) are genetic elements widespread in many bacteria that were historically associated with bacterial persistence. Their presence on mycoplasma genomes has never been carefully assessed, especially for pathogenic species. Here we investigated three candidate TA systems in M. mycoides subsp. capri encoding a (i) novel AAA-ATPase/subtilisin-like serine protease module, (ii) a putative AbiEii/AbiEi pair and (iii) a putative Fic/RelB pair. We sequence analyzed fourteen genomes of M. mycoides subsp. capri and confirmed the presence of at least one TA module in each of them. Interestingly, horizontal gene transfer signatures were also found in several genomic loci containing TA systems for several mycoplasma species. Transcriptomic and proteomic data confirmed differential expression profiles of these TA systems during mycoplasma growth in vitro. While the use of heterologous expression systems based on E. coli and B. subtilis showed clear limitations, the functionality and neutralization capacities of all three candidate TA systems were successfully confirmed using M. capricolum subsp. capricolum as a host. Additionally, M. capricolum subsp. capricolum was used to confirm the presence of functional TA system homologs in mycoplasmas of the Hominis and Pneumoniae phylogenetic groups. Finally, we showed that several of these M. mycoides subsp. capri toxins tested in this study, and particularly the subtilisin-like serine protease, could be used to establish a kill switch in mycoplasmas for industrial applications.

Integrating the Human and Animal Sides of Mycoplasmas Resistance to Antimicrobials

Mycoplasma infections are frequent in humans, as well as in a broad range of animals. However, antimicrobial treatment options are limited, partly due to the lack of a cell wall in these peculiar bacteria. Both veterinary and human medicines are facing increasing resistance prevalence for the most commonly used drugs, despite different usage practices. To date, very few reviews have integrated knowledge on resistance to antimicrobials in humans and animals, the latest dating back to 2014. To fill this gap, we examined, in parallel, antimicrobial usage, resistance mechanisms and either phenotype or genotype-based methods for antimicrobial susceptibility testing, as well as epidemiology of resistance of the most clinically relevant human and animal mycoplasma species. This review unveiled common features and differences that need to be taken into consideration in a "One Health" perspective. Lastly, two examples of critical cases of multiple drug resistance are highlighted, namely, the human M. genitalium and the animal M. bovis species, both of which can lead to the threat of untreatable infections.

Transboundary Animal Diseases, an Overview of 17 Diseases with Potential for Global Spread and Serious Consequences

Animals provide food and other critical resources to most of the global population. As such, diseases of animals can cause dire consequences, especially disease with high rates of morbidity or mortality. Transboundary animal diseases (TADs) are highly contagious or transmissible, epidemic diseases, with the potential to spread rapidly across the globe and the potential to cause substantial socioeconomic and public health consequences. Transboundary animal diseases can threaten the global food supply, reduce the availability of non-food animal products, or cause the loss of human productivity or life. Further, TADs result in socioeconomic consequences from costs of control or preventative measures, and from trade restrictions. A greater understanding of the transmission, spread, and pathogenesis of these diseases is required. Further work is also needed to improve the efficacy and cost of both diagnostics and vaccines. This review aims to give a broad overview of 17 TADs, providing researchers and veterinarians with a current, succinct resource of salient details regarding these significant diseases. For each disease, we provide a synopsis of the disease and its status, species and geographic areas affected, a summary of in vitro or in vivo research models, and when available, information regarding prevention or treatment.

LncRNA NEAT1 activates MyD88/NF-κB pathway in bronchopneumonia through targeting miR-155-5p

BACKGROUND

Bronchopneumonia is a disease of the respiratory tract. It leads to other complications and endangers life and health. Long non-coding RNA (lncRNA) participates in the occurrence and development of bronchopneumonia. Nuclear paraspeckle assembly transcript 1 (NEAT1) plays a key role in inflammatory diseases, but the function of NEAT1 in bronchopneumonia remains unclear.

METHODS

RT-qPCR and Western blotting were performed to determine genes and proteins expressions. MTT was applied to test cell viability. Cell apoptosis was detected by flow cytometry. RIP was used to investigate the correlation between NEAT1 and miR-155-5p. The interaction between miR-155-5p and NEAT1 or MyD88 was evaluated by the dual-luciferase reporter gene.

RESULTS

NEAT1 and MyD88 were upregulated in BEAS-2B cells by LPS, while miR-155-5p was downregulated. Knockdown of NEAT1 inhibited LPS-induced BEAS-2B cells growth inhibition by inhibiting the apoptosis. In addition, NEAT1 silencing suppressed LPS-induced inflammatory responses in BEAS-2B cells via suppression of TNF-α, IL-1β, IL-6, and IL-18. Meanwhile, NEAT1 is directly bound to miR-155-5p to regulate MyD88/NF-κB axis, and overexpression of miR-155-5p increased cell proliferation and suppressed inflammatory factors expression levels and cell apoptosis. Furthermore, sh-NEAT1-induced inhibition of BEAS-2B cells injury was partially reversed by miR-155-5p inhibitor or MyD88 overexpression.

CONCLUSION

NEAT1 silencing suppressed LPS-induced BEAS-2B cells injury and inflammation by the mediation of miR-155-5p/MyD88/NF-κB axis. Thus, our study might shed new light on exploring the new strategies for the treatment of bronchopneumonia.

Reproduction of contagious bovine pleuropneumonia via aerosol-based challenge with Mycoplasma mycoides subsp. mycoides

Contagious bovine pleuropneumonia (CBPP) is a respiratory disease caused by Mycoplasma mycoides subsp. mycoides. Infection occurs via Mycoplasma-containing droplets and therefore requires close contact between animals. The current infection models are suboptimal and based on intratracheal installation of mycoplasmas or in-contact infection. This work tested the infection of adult cattle via aerosols containing live mycoplasmas mimicking the infection of cattle in the field. Therefore, we infected six cattle with aerosolized Mycoplasma mycoides subsp. mycoides strain Afadé over seven consecutive days with altogether 10⁹ colony forming units. All animals seroconverted between 11–24 days post infection and five out of six animals showed typical CBPP lesions. One animal did not show any lung lesions at necropsy, while another animal had to be euthanized at 25 days post infection because it reached endpoint criteria. Seroconversion confirmed successful infection and the spectrum of clinical and lesions observed mirrors epidemiological models and the field situation, in which only a fraction of animals suffers from acute clinical disease post infection.