A participatory approach to understand the attitudes and perceptions towards priority endemic cattle diseases among dairy farmers and animal health experts in Henan province, China.

The dairy industry is threatened by a variety of endemic diseases and emerging diseases, and various control programs have been initiated in China. The increased application of evidence to policymaking can help improve the efficiency of disease control programs; however, the relevant research literature is currently lacking. The objective of this study was to gain an in-depth understanding of the attitudes and perceptions towards priority endemic diseases among dairy farmers and animal health experts by taking Henan province of China as the example and using semi-structured interviews and focus group discussions, respectively. This study involved 24 farmers and 27 animal health experts from December 2019 to January 2021. The diseases considered by farmers to be of significance to their animals are different from those considered priorities by the participating experts and the government list. From the perspective of the individual farmers, the effects of zoonotic disease risks such as bovine brucellosis and tuberculosis appear to be less pronounced than "visible" losses at the farm level, contrary to the opinion of experts. Participating experts believed that poor on-farm biosecurity measures posed challenges to the control and eradication of priority endemic diseases; however, there are gaps in farmers' understanding of biosecurity principles, and low motivations to take such disease prevention measures. Several other challenges to the control and eradication of priority endemic diseases also emerged in the data, including the lack of diagnostic tools applicable in the field as well as differential diagnostic tools to differentiate natural infection from vaccination, lack of effective and commercially available vaccines against single or multiple pathogen(s) or new genotypes/serotypes, weak early warning and information networks and insufficient economic compensation. A holistic understanding of people's perceptions of disease control would facilitate the implementation of inclusive and engaging disease control strategies, thereby increasing the efficiency of disease control.

Evaluation of a novel chimeric B cell epitope-based vaccine against mastitis induced by either Streptococcus agalactiae or Staphylococcus aureus in mice.

To construct a universal vaccine against mastitis induced by either Streptococcus agalactiae or Staphylococcus aureus, the B cell epitopes of the surface immunogenic protein (Sip) from S. agalactiae and clumping factor A (ClfA) from S. aureus were analyzed and predicted. sip-clfA, a novel chimeric B cell epitope-based gene, was obtained by overlap PCR, and then the recombinant Sip-ClfA (rSip-ClfA) was expressed and purified. rSip-ClfA and inactivated S. agalactiae and S. aureus were formulated into different vaccines with mineral oil as the adjuvant and evaluated in mouse models. The rSip-ClfA vaccination induced immunoglobulin G (IgG) titers higher than those seen in groups immunized with inactivated bacteria. Furthermore, the response to rSip-ClfA immunization was characterized as having a dominant IgG1 subtype, whereas both bacterial immunizations produced similar levels of IgG1 and IgG2a. The antiserum capacities for opsonizing adhesion and phagocytosis were significantly greater in the rSip-ClfA immunization group than in the killed-bacterium immunization groups (P < 0.05). The immunized lactating mice were challenged with either S. agalactiae or S. aureus via the intramammary route. At 24 h postinfection, the numbers of bacteria recovered from the mammary glands in the rSip-ClfA group were >5-fold lower than those in both inactivated-bacterium groups (P < 0.01). Histopathological examination of the mammary glands showed that rSip-ClfA immunization provided better protection of mammary gland tissue integrity against both S. agalactiae and S. aureus challenges. Thus, the recombinant protein rSip-ClfA would be a promising vaccine candidate against mastitis induced by either S. agalactiae or S. aureus.

Microarray analysis of the chelerythrine-induced transcriptome of Mycobacterium tuberculosis.

Chelerythrine (a natural quaternary benzophenanthridine alkaloid) is an extract from the roots of Chelidonium majus with potential antimycobacterial activity. To reveal the possible mechanism of action of chelerythrine against Mycobacterium tuberculosis (M. tuberculosis), commercial oligonucleotide microarrays were used to analyze the genome-wide transcriptional changes triggered by treatment with subinhibitory concentrations of chelerythrine. Quantitative real-time RT-PCR was performed for selected genes to verify the microarray results. We interpreted our microarray data using Agilent software. Analysis of the microarray data revealed that a total of 759 genes were differentially regulated by chelerythrine. Of these, 372 genes were upregulated, and 387 genes were downregulated. Some of the important genes that were significantly regulated are related to different pathways (such as urease), methoxy-mycolic acid synthase, surface-exposed lipids, the heat shock response, and protein synthesis. This genome-wide transcriptomics approach produced the first insights into the response of M. tuberculosis to a chelerythrine challenge.

Evaluation of clumping factor A binding region A in a subunit vaccine against Staphylococcus aureus-induced mastitis in mice.

The present study evaluated the potential of recombinant binding region A of clumping factor A (rClfA-A) to be an effective component of a vaccine against mastitis induced by Staphylococcus aureus in the mouse. rClfA-A and inactivated S. aureus were each emulsified in Freund's adjuvant, mineral oil adjuvant, and Seppic adjuvant; phosphate-buffered saline was used as a control. Seven groups of 12 mice each were immunized intraperitoneally three times at 2-week intervals. The titers of IgG and subtypes thereof (IgG1 and IgG2a) in the rClfA-A-immunized group were more than 1,000-fold higher than those in the killed-bacteria-immunized group (P < 0.01). Of the three adjuvants used, mineral oil adjuvant induced the highest antibody levels for both antigens (P < 0.001). Furthermore, the anti-rClfA-A antibody capacities for bacterial adhesion and opsonizing phagocytosis were significantly greater in the rClfA-A-immunized group than in the killed-bacteria-immunized group (P < 0.05). Lactating mice immunized with either rClfA-A or inactivated vaccine were challenged with S. aureus via the intramammary route. The numbers of bacteria recovered from the murine mammary glands 24 h after inoculation were significantly lower in the rClfA-A group than in the killed-bacteria-immunized group (P < 0.001). Histologic examination of the mammary glands showed that rClfA-A immunization effectively preserved tissue integrity. Thus, rClfA-A emulsified in an oil adjuvant provides strong immune protection against S. aureus-induced mastitis in the mouse.

Protective effect of ligand-binding domain of fibronectin-binding protein on mastitis induced by Staphylococcus aureus in mice.

The immunoprotective effect of the ligand-binding domain of fibronectin-binding protein (lFnBP) from Staphylococcus aureus (S. aureus) was investigated in a mouse mastitis model. The recombinant lFnBP (rlFnBP) and inactivated S. aureus were emulsified in Freund's adjuvant, mineral oil adjuvant or Seppic adjuvant, respectively. Seven groups of mice (n=12 each) were immunized with these six vaccines or phosphate-buffered saline. The immunoglobulin G (IgG) titers of mice immunized with rlFnBP vaccine were higher than those in the inactivated vaccine group (P<0.01). Antiserum capacities to opsonize adhesion and phagocytosis were significantly greater in the rlFnBP immunization group than in the killed bacteria group (P<0.05). The immunized lactating mice were challenged with S. aureus. At 24h postinfection, the numbers of bacteria recovered in the rlFnBP group were significantly lower than those in the killed bacteria group (P<0.001). Levels of both interleukin-6 (IL-6) and interferon-gamma (IFN-gamma from the mammary glands in the rlFnBP group were higher than those in the inactivated group (P<0.05). Better protection of mammary gland tissue was shown in the rlFnBP group. Thus, the rlFnBP, emulsified in an oil adjuvant, provided strong immune protection against S. aureus mastitis in mice, and could therefore be a promising vaccine candidate against bovine mastitis induced by S. aureus.