Prevalence of Haemophilus parasuis"Glaesserella parasuis" in pigs in China: A systematic review and meta-analysis.

Streptococcus suis (S. suis) type 2 (SS2) is an important zoonotic pathogen that causes swine streptococcosis, a widespread infectious disease that occurs in pig production areas worldwide and causes serious economic losses in the pork industry. Hosts recognize pathogen-associated molecular patterns (PAMPs) through pattern recognition receptors (PRRs) to activate both innate and acquired immune responses. However, S. suis has evolved multiple mechanisms to escape host defenses. Pathogenic proteins, such as enolase, double-component regulatory systems, factor H-combining proteins and other pathogenic and virulence factors, contribute to immune escape by evading host phagocytosis, reactive oxygen species (ROS), complement-mediated immune destruction, etc. SS2 can prevent neutrophil extracellular trap (NET) formation to avoid being trapped by porcine neutrophils and disintegrate host immunoglobulins via IgA1 hydrolases and IgM proteases. Currently, the pathogenesis of arthritis and meningitis caused by SS2 infection remains unclear, and further studies are necessary to elucidate it. Understanding immune evasion mechanisms after SS2 infection is important for developing high-efficiency vaccines and targeted drugs.

How Streptococcus suis serotype 2 attempts to avoid attack by host immune defenses

Seroprevalence and risk factors associated with Haemophilus parasuis infection in Tibetan pigs in Tibet

https://www.mdpi.com/2076-393X/7/3/71/pdf

Novel Candidates for Vaccine Development Against Mycoplasma Capricolum Subspecies Capripneumoniae (Mccp)—Current Knowledge and Future Prospects

Purpose.
Mycoplasma ovipneumoniae is a pathogen that causes atypical pneumoniae in sheep and goats. While infection of lambs can induce strong immune responses, typically measured as serum antibodies, experimental vaccines appear to induce lower antibody titres. The purpose of this study was to better understand the bacterium and its interaction with the host, in order to improve the vaccination strategy.
Methodology. We designed primers to compare seven M. ovipneumoniae gene sequences, in addition to the 16S sequence typically used, to estimate the variability between isolates. In addition, we labelled bacteria with a two-step process to examine whether bacteria could be intracellular as well as on the host surface in vitro. Finally, we vaccinated sheep four times and examined the induction of humoral and cellular responses.
Results. We were able to reliably amplify the seven housekeeping gene sequences to examine variability of the different isolates, and the bacteria could be found intracellularly, as well as on the host cell surface. Four vaccinations of sheep produced only modest humoral and cellular responses in this study, likely due to previous exposure of the animals to mycoplasmas.
Conclusions. The moderate immune responses seen in this study indicate that previous exposure to mycoplasmas is a challenge for vaccination of lambs against M. ovipneumoniae. However, an alternative vaccination strategy, e.g. utilizing a recombinant vaccine, may overcome this vaccination hurdle in endemic regions and we suggest a possible vaccine candidate.

Icelandic ovine Mycoplasma ovipneumoniae are variable bacteria that induce limited immune responses in vitro and in vivo.

Received: Revised: Accepted: October 26, 2012 May 16, 2013 June 22, 2013 Mycoplasma ovipneumoniae is considered as an important pathogen of small ruminants, but its antigenic proteins are not well known so far In this study, we cloned the EF-Tu gene of M ovipneumoniae and analyzed the molecular features of the gene and its coding protein for the first time The gene was then expressed in Ecoli and the antigenicity of the coding protein was evaluated as well The EF-Tu gene of M ovipneumoniae is 1209 bp in length, encodes 402 amino acids, and shares the highest DNA sequence identity of 875% and deduced amino acid sequence identity of 978% with those of M hyopneumoniae, respectively The recombinant EF-Tu protein can react with the polyclonal antiserum of M ovipneumoniae and can induce humoral immune responses in mice, which indicated that the EF-Tu may be used as a candidate protein in developing the technologies to control the disease ©2013 PVJ All rights reserved

Characterization of elongation factor Tu of Mycoplasma ovipneumoniae.

Optimizing and expressing of proteins including PDHA, PDHB and PDHC of Mycoplasma capricolum sub sp. capripneumoniae.

A polymerase chain reaction (PCR) test for the identification of Mycoplasma capricolum subsp. capripneumoniae (Mccp) was optimized using the H2 gene sequences of M1601. The test was evaluated on 20 strains including six representative strains of the Mycoplasma mycoides cluster as well as 13 field isolates from China, Pasteurella multocida and Mannheimia haemolytica. To obtain a test that was specific for Mccp, the PCR produced an amplicon of approximately 680 bp only with the Mccp strains. The specificity of the present PCR was found to be 100% specific for Mccp. The sensitivity of the PCR showed that it could detect a minimum of 0.75 ng of purified DNA. For further evaluation, clinical samples tested by PCR included lung and liquor pleurae from 14 goats artificially infected with Mccp. The PCR was positive in all the clinical samples both in the undiluted and 50-fold dilutions of extracted DNA except for a sample of liquor pleurae. However, the latter showed weak bands. An epidemiological survey was also performed using the constructed PCR methods and results indicated that 36 of 61 of these samples including tissue and percolate from Western China were considered positive. The coincidence rate was 82% compared with the performance of a PCR test earlier published. The present PCR represents a rapid and reliable method for genetically based identification of Mccp. The specificity of the test makes it suitable for detection of Mccp in clinical samples.

	 

	Key words: Mycoplasma capricolum subsp. capripneumoniae, PCR, identification

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Improvement of specific polymerase chain reaction (PCR) for the identification of Mycoplasma capricolum subsp. capripneumoniae

The purpose of this study is to establish the guinea pigs model for Haemophilus parasuis infectionThe guinea pigs were experimentally infected with 20×109 CFU/mL Hparasuis serotype 5,and the organs of the dead guinea pigs,including the brain,heart,lung,liver,spleen and kidney were examined for pathological changes and compared with that of Classer's disease in pigsThe bacteria was isolated from the collected samples and confirmed by PCRThe pathological changes were observed in the dead guinea pigs which were similar to that of Classer's disease in pigsHparasuis serotype 5 was isolated from the brain,blood,lung,liver,spleen and kidney of the guinea pigsThese results showed that the guinea pigs could be used as an effective animal model for the pathogenesis,immunization and dignosis studies of Glasser's disease

Establishment of guinea pigs model for Haemophilus parasuis infection.

Indirect hemagglutination assay(IHA) was applied to undertaken the epidemiological investigation of Haemophilus parasuis in part area of Fujian province to study the epidemiological situation.Results showed that total positives rate of H.parasuis in part area of Hujian was 6.5%,among them,the positives rate of sow was 8.75%,and higher than other swine.

He Ying

Papers

Characterization of elongation factor Tu of Mycoplasma ovipneumoniae.

Optimizing and expressing of proteins including PDHA, PDHB and PDHC of Mycoplasma capricolum sub sp. capripneumoniae.

Improvement of specific polymerase chain reaction (PCR) for the identification of Mycoplasma capricolum subsp. capripneumoniae

Establishment of guinea pigs model for Haemophilus parasuis infection.

Epidemiological investigation of Haemophilus parasuis in part area of Fujian province.