Blastocystis is a common protist that can infect domestic and wild animals worldwide. Yak (Bos grunniens), an ancient species which can survive in alpine regions, has supplied necessities to local residents in plateau areas for generations. However, the infections with Blastocystis in yaks has been ignored for a long time. In the present study, the infections and genotypes of Blastocystis spp. in domestic yaks from Qinghai Province (northwestern China) were explored. Of 1027 faecal samples collected from yaks in seven regions of Qinghai Province, northwestern China, the total prevalence of Blastocystis was 27.07% (278/1027) targeting the small subunit ribosome rRNA (SSU rRNA) gene. This protist was detected in yaks within each examined age group, geographical origin and season. Significant difference in prevalence was found in yaks from different geographical origins. The highest prevalence (48.94%) was observed in animals from Haixi county. Sequence analysis revealed three animal-specific subtypes (ST10, ST12 and ST14) of Blastocystis spp. in these yaks, with ST10 being the predominant subtype widely distributed in all investigated regions, seasons and age groups. Interestingly, this is the first report about subtype ST12 infecting yaks. To our knowledge, this is the first systematic report on Blastocystis prevalence in yaks from China, and the findings provide fundamental data for establishing effective control measures for this protist in yaks as well as other animals in China.

Giardiasis, caused by Giardia duodenalis (syn. Giardia intestinalis, Giardia lamblia), is a significant zoonotic parasitic disease of animals and humans worldwide. Accurate genotyping of G. duodenalis is essential for efficient control and management of giardiasis. The objectives of the present study were to investigate the prevalence and assemblages of giardiasis in pigs in Shaanxi Province, northwestern China, and for the first time study multilocus genotypes (MLGs) in pigs using multilocus genotyping technology in this region. Of 560 faecal samples collected from five farms in Shaanxi Province, 45 were positive for G. duodenalis and significant differences in prevalence were observed among different locations. Differences in prevalence were also detected in pigs of different age groups, with the highest prevalence in sows and the lowest in boars. Two assemblages, A and E, were identified, and a mixed infection of both A and E was identified in one faecal sample. Assemblage E was predominant and widely distributed in all investigated areas and age groups. Genetic viability was detected for both assemblages, and four different multi-locus genotypes (MLGs) within assemblage E were found, MLGE1-MLGE4. Giardia duodenalis was detected in pigs from Shaanxi Province, northwestern China, and genetic diversity was observed in these infections. Both assemblages A and E were detected, and four distinct MLGs within assemblage E were identified. These findings provide new data for controlling G. duodenalis infection in pigs.

Background: Cryptosporidium is an important zoonotic pathogen responsible for severe enteric diseases in humans and animals. However, the molecular mechanisms underlying host and Cryptosporidium interactions are still not clear. Methods: To study the roles of circRNAs in host cells during Cryptosporidium infection, the expression profiles of circRNAs in HCT-8 cells infected with C. parvum were investigated using a microarray assay, and the regulatory role of a significantly upregulated circRNA, ciRS-7, was investigated during C. parvum infection. Results: C. parvum infection caused notable alterations in the expression profiles of circRNAs in HCT-8 cells, and a total of 178 (including 128 up- and 50 downregulated) circRNAs were significantly differentially expressed following C. parvum infection. Among them, ciRS-7 was significantly upregulated and regulated the NF-κB signaling pathway by sponging miR-1270 during C. parvum infection. Furthermore, the ciRS-7/miR-1270/relA axis markedly affected the propagation of C. parvum in HCT-8 cells. Conclusions: Our results revealed that ciRS-7 would promote C. parvum propagation by regulating the miR-1270/relA axis and affecting the NF-κB pathway. To the best of our knowledge, this is the first study to investigate the role of circRNA during Cryptosporidium infection, and the findings provide a novel view for implementing control strategies against Cryptosporidium infection. Graphical

Background: Eimeria necatrix, the most highly pathogenic coccidian in chicken small intestines, can cause high morbidity and mortality in susceptible birds and devastating economic losses in poultry production, but the underlying molecular mechanisms in interaction between chicken and E. necatrix are not entirely revealed. Accumulating evidence shows that the long-non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) are key regulators in various infectious diseases. However, the expression profiles and roles of these two non-coding RNAs (ncRNAs) during E. necatrix infection are still unclear. Methods: The expression profiles of mRNAs, lncRNAs and circRNAs in mid-segments of chicken small intestines at 108 h post-infection (pi) with E. necatrix were analyzed by using the RNA-seq technique. Results: After strict filtering of raw data, we putatively identified 49,183 mRNAs, 818 lncRNAs and 4153 circRNAs. The obtained lncRNAs were classified into four types, including 228 (27.87%) intergenic, 67 (8.19%) intronic, 166 (20.29%) anti-sense and 357 (43.64%) sense-overlapping lncRNAs; of these, 571 were found to be novel. Five types were also predicted for putative circRNAs, including 180 exonic, 54 intronic, 113 antisense, 109 intergenic and 3697 sense-overlapping circRNAs. Eimeria necatrix infection significantly altered the expression of 1543 mRNAs (707 upregulated and 836 downregulated), 95 lncRNAs (49 upregulated and 46 downregulated) and 13 circRNAs (9 upregulated and 4 downregulated). Target predictions revealed that 38 aberrantly expressed lncRNAs would cis-regulate 73 mRNAs, and 1453 mRNAs could be trans-regulated by 87 differentially regulated lncRNAs. Additionally, 109 potential sponging miRNAs were also identified for 9 circRNAs. GO and KEGG enrichment analysis of target mRNAs for lncRNAs, and sponging miRNA targets and source genes for circRNAs identified associations of both lncRNAs and circRNAs with host immune defense and pathogenesis during E. necatrix infection. Conclusions: To the best of our knowledge, the present study provides the first genome-wide analysis of mRNAs, lncRNAs and circRNAs in chicken small intestines infected with E. necatrix. The obtained data will offer novel clues for exploring the interaction mechanisms between chickens and Eimeria spp.

Background: Cryptosporidium baileyi is an economically important zoonotic pathogen that causes serious respiratory symptoms in chickens for which no effective control measures are currently available. An accumulating body of evidence indicates the potential and usefulness of metabolomics to further our understanding of the interaction between pathogens and hosts, and to search for new diagnostic or pharmacological biomarkers of complex microorganisms. The aim of this study was to identify the impact of C. baileyi infection on the serum metabolism of chickens and to assess several metabolites as potential diagnostic biomarkers for C. baileyi infection. Methods: Ultraperformance liquid chromatography-mass spectrometry (UPLC-MS) and subsequent multivariate statistical analysis were applied to investigate metabolomics profiles in the serum samples of chickens infected with C. baileyi, and to identify potential metabolites that can be used to distinguish chickens infected with C. baileyi from non-infected birds. Results: Multivariate statistical analysis identified 138 differential serum metabolites between mock- and C. baileyi-infected chickens at 5 days post-infection (dpi), including 115 upregulated and 23 downregulated compounds. These metabolites were significantly enriched into six pathways, of which two pathways associated with energy and lipid metabolism, namely glycerophospholipid metabolism and sphingolipid metabolism, respectively, were the most enriched. Interestingly, some important immune-related pathways were also significantly enriched, including the intestinal immune network for IgA production, autophagy and cellular senescence. Nine potential C. baileyi-responsive metabolites were identified, including choline, sirolimus, all-trans retinoic acid, PC(14:0/22:1(13Z)), PC(15:0/22:6(4Z,7Z,10Z,13Z,16Z,19Z)), PE(16:1(9Z)/24:1(15Z)), phosphocholine, SM(d18:0/16:1(9Z)(OH)) and sphinganine. Conclusions: This is the first report on serum metabolic profiling of chickens with early-stage C. baileyi infection. The results provide novel insights into the pathophysiological mechanisms of C. baileyi in chickens. Graphic