Little information is available regarding the knowledge, attitudes and practices (KAP) of the owners of yaks in Tibet with respect to brucellosis. This manuscript reports on the results of a cross-sectional survey using a structured questionnaire investigating the KAP of 317 yak herders from 34 villages in the three main yak-rearing counties of Maizhokunggar, Damxung and Yadong from April to August 2015. Although 60.6% of the respondents had heard of brucellosis, there was an overall low level of knowledge about the disease. Herders did, however, adopt management/husbandry practices which would reduce transmission of the disease to humans and other animals. Multivariable logistic modelling showed that a better knowledge was predicted by age, production system adopted, education level and number of people in a household. Differences in attitudes and practices were predicted by education level, production system and household size. In order to increase the awareness of herders on brucellosis and to reduce the risk of infection in both humans and other animals, public health education campaigns should be developed and offered to livestock owners in Tibet.

The present study determined the complete mitochondrial DNA (mt DNA) sequence of Fasciola intermediate (isolated from yaks) based on gene content and genome organization. According to our findings, the genome of Fasciola intermediate was 13,960 bp in length, containing 2 ribosomal RNA (rRNA) genes, 12 protein-coding genes (PCGs), and 22 transfer RNA (tRNA) genes. The A+T content of genomes was 63.19%, with A (15.17%), C (9.31%), G (27.51%), and T as the nucleotide composition (48.02%). Meanwhile, the results showed negative AT-skew (-0.52) and positive GC-skew (0.494). The AT bias significantly affected both the codon usage pattern and amino acid composition of proteins. There were 2715 codons in all 12 protein-coding genes, excluding termination codons. Leu (16.72%) was the most often used amino acid, followed by Val (12.74%), Phe (10.90%), Ser (10.09%), and Gly (8.39%). A phylogenetic tree was built using Maximum-Likelihood (ML) through MEGA 11.0 software. The entire mt DNA sequence of Fasciola intermediate gave more genetic markers for investigating Trematoda population genetics, systematics, and phylogeography. Hence, for the first time, our study confirmed that yaks on the Qinghai-Tibet plateau have the infestation of Fasciola intermediate parasite.

Mastitis is an inflammation of the mammary gland that can be caused by various factors, including biological, chemical, mechanical, or physical. Microbiological culture, DNA techniques, and high-throughput next-generation sequencing have been used to identify mastitis-causing pathogens in various animal species. However, little is known about microbiota and microbiome changes linked to yak milk mastitis. This study aimed to characterize the milk microbiota of healthy and mastitis-infected yaks using full-length 16S rRNA sequencing. The results showed that the bacterial microbiota comprises 7 phyla, 9 classes, 20 orders, 39 families, 59 genera, and 72 species. Proteobacteria and Firmicutes were the predominant microbial communities, with lower abundances of Bacteroidota, Actinobacteriota, Acidobacteriota, and other minor groupings also observed. Proteobacteria dominated the clinical and subclinical mastitis groups (95.36% and 89.32%, respectively), in contrast to the healthy group (60.17%). Conversely, Firmicutes were more common in the healthy group (39.7%) than in the subclinical and clinical mastitis groups (10.49% and 2.92%, respectively). The predominant organisms found in the healthy group were Leuconostoc mesenteroides, Lactococcus piscium, Carnobacterium maltaromaticum, and Lactococcus raffinolactis. Low abundances of Staphylococcus aureus species were found in both subclinical and clinical mastitis groups, with Moraxella osloensis and Psychrobacter cibarius dominating the subclinical mastitis group and Pseudomonas fluorescens dominating the clinical mastitis group. An alpha diversity study revealed that the healthy group had a higher microbial diversity than the clinical and subclinical mastitis groups. According to beta-diversity analysis, the principal coordinate analysis identified that mastitis-infected samples significantly differed from healthy ones. The milk microbiota of healthy yaks is more varied, and specific prominent taxa within various groups can act as marker microorganisms for mastitis risk. The genera Leuconostoc and Lactococcus are promising candidates for creating probiotics.

Bovine norovirus (BNoV) and bovine nebovirus (BNeV) are emerging pathogens responsible for severe diarrhea in calves worldwide. In this study, we constructed a bivalent recombinant adenovirus vector vaccine, designated rAd5-BNoV + BNeV_VP1 encoding the genes for BNoV-VP1 and BNeV-VP1 based on replication-deficient human adenovirus type 5 (rAd5), and evaluated its immunogenicity in mice and calves. Serum antibody responses were assessed by enzyme-linked immunosorbent assay (ELISA) and serum blocking titer 50 (BT50). Results demonstrated that mice immunized with rAd5-BNoV + BNeV_VP1 produced significant VP1-specific IgG titers as early as two weeks post-vaccination. BNoV-VP1-specific IgG antibody titers peaked at 1:10⁵ in both intramuscular (I.M.) and oral groups (n = 6), while BNeV-VP1-specific IgG titers peaked at 1:10⁵ in the I.M. groups (n = 6) and 1:10⁴ in the oral groups (n = 6). The BT50 values peaked at 640 in the I.M. groups and 576 in the oral groups (n = 6). Furthermore, the percentages of IL-4-producing cells and CD3⁺CD8⁺ T cells in splenocytes were significantly elevated in mice immunized via the I.M. route. The vaccine also elicited a robust humoral immune response in calves. Following a booster I.M. injection with rAd5-BNoV + BNeV_VP1, serum BNoV-VP1-specific and BNeV-VP1-specific IgG antibody titers were significantly higher (P ≤ 0.001) compared to controls. The BT50 in immunized calves reached 1:80 at 21 and 35 days post-immunization. These results collectively indicate that rAd5-BNoV + BNeV_VP1 effectively induces immunity against BNoV and BNeV infection.