BACKGROUND:Babesiosis is an emerging zoonosis worldwide that is caused by tick-borne apicomplexans, Babesia spp., which threatens the health of domesticated and wild mammals and even humans. Although it has done serious harm to animal husbandry and public health, the study of Babesia is still progressing slowly. Until now, no effective anti-Babesia vaccines have been available, and administration of combined drugs tends to produce side effects. Therefore, non-targeted metabolomics was employed in the present study to examine the temporal dynamic changes in the metabolic profile of the infected erythrocytes. The goal was to obtain new insight into pathogenesis of Babesia and to explore vaccine candidates or novel drug targets.METHODS:C57BL/6 mice were infected with B. microti and erythrocytes at different time points (0, 3, 6 , 9, 12, and 22-days post-infection) were subjected to parasitemia surveillance and then metabolomics analysis using liquid chromatography-mass spectrometry (LC-MS). Multivariate statistical analyses were performed to clearly separate and identify dysregulated metabolites in Babesia-infected mice. The analyses included principal components analysis (PCA) and orthogonal partial least squares-discrimination analysis (OPLS-DA). The time-series trends of the impacted molecules were analyzed using the R package Mfuzz and the fuzzy clustering principle. The temporal profiling of amino acids, lipids, and nucleotides in blood cells infected with B. microti were also investigated.RESULTS:B. microti infection resulted in a fast increase of parasitemia and serious alteration of the mouse metabolites. Through LC-MS metabolomics analysis, 10,289 substance peaks were detected and annotated to 3,705 components during the analysis period. There were 1,166 dysregulated metabolites, which were classified into 8 clusters according to the temporal trends. Consistent with the trend of parasitemia, the numbers of differential metabolites reached a peak of 525 at 6-days post-infection (dpi). Moreover, the central carbon metabolism in cancer demonstrated the most serious change during the infection process except for that observed at 6 dpi. Sabotage occurred in components involved in the TCA cycle, amino acids, lipids, and nucleotide metabolism.CONCLUSION:Our findings revealed a great alteration in the metabolites of Babesia-infected mice and shed new light on the pathogenesis of B. microti at the metabolic level. The results might lead to novel information about the mechanisms of pathopoiesis, babesisosis, and anti-parasite drug/vaccine development in the future.

Cryptosporidium parvum is a major cause of diarrheal disease in immature or weakened immune systems, mainly in infants and young children in resource-poor settings. Despite its high prevalence, fully effective and safe drugs for the treatment of C. parvum infections remain scarce, and there is no vaccine. Meanwhile, curcumin has shown protective effects against C. parvum infections. However, the mechanisms of action and relationship to the gut microbiota and innate immune responses are unclear. Immunosuppressed neonatal mice were infected with oocysts of C. parvum and either untreated or treated with a normal diet, curcumin or paromomycin. We found that curcumin stopped C. parvum oocysts shedding in the feces of infected immunosuppressed neonatal mice, prevented epithelial damage, and villi degeneration, as well as prevented recurrence of infection. Curcumin supplementation increased the relative abundance of Bacteroidetes and decreased the relative abundance of Firmicutes and Proteobacteria in mice infected with C. parvum as shown by 16S rRNA gene sequencing analysis. The relative abundance of Lactobacillus, Bacteroides, Akkermansia, Desulfovibrio, Prevotella, and Helicobacter was significantly associated with C. parvum infection inhibited by curcumin. Curcumin significantly (P < 0.01) suppressed IFN-γ and IL -18 gene expression levels in immunosuppressed neonatal C. parvum-infected mice. We demonstrate that the therapeutic effects curcumin are associated with alterations in the gut microbiota and innate immune-related genes, which may be linked to the anti-Cryptosporidium mechanisms of curcumin.

Although the prevalence of schistosomiasis japonica has declined gradually in China, more accurate and sensitive diagnostic methods are urgently needed for the prevention and control of this disease. Molecular diagnostic methods are advantageous in terms of sensitivity and specificity, but they are time-consuming and require expensive instruments and skilled personnel, which limits their application in low-resource settings. In this study, an isothermal DNA amplification assay and recombinase polymerase amplification (RPA) combined with lateral flow dipstick (LFD) were set up. It was used to detect S. japonicum infections in experimental mice and domestic goats by amplifying a specific DNA fragment of S. japonicum. The lower limit of detection for the LFD-RPA assay was evaluated using dilutions of plasmid containing the target sequence. Cross-reactivity was evaluated using genomic DNA from eight other parasites. The effectiveness of the LFD-RPA assay was verified by assessing 36 positive plasma samples and 36 negative plasma samples from mice. The LFD-RPA assay and real-time PCR were also used to assess 48 schistosomiasis japonica-positive plasma samples and 53 negative plasma samples from goats. The LFD-RPA assay could detect 2.6 femtogram (fg) of S. japonicum target DNA (~39 fg genomic DNA of S. japonicum), only 10-fold less sensitive than real-time PCR assay. There was no cross-reactivity with DNA from the other eight parasites, such as Haemonchus contortus and Spirometra. The whole amplification process could be completed within 15 min at 39°C, and the results can be observed easily using the LFD. The sensitivity and specificity of the LFD-RPA assay were 97.22% (35/36, 95% CI, 85.47%–99.93%) and 100% (36/36, 95% CI, 90.26%–100%) in mice, and 93.75% (45/48, 95% CI, 82.80%–98.69%) and 100% (53/53, 95% CI, 93.28%–100%) in goats. By comparison, the sensitivity and specificity of real-time PCR were 100% (36/36, 95% CI, 90.26%–100%) and 100% (36/36, 95% CI, 90.26%–100%) for mice, and 97.92% (47/48, 95% CI, 88.93%–99.95%) and 100% (53/53, 95% CI, 93.28%–100%) for goats. The LFD-RPA assay exhibits high sensitivity and specificity for the diagnosis of schistosomiasis japonica, and it is an alternative method for diagnosis schistosomiasis japonica in low resource setting.

Haemaphysalis longicornis is a blood-feeding hard tick known for transmitting a variety of pathogens, including Babesia. How the parasites in the imbibed blood become anchored in the midgut of ticks is still unknown. ABSTRACT Haemaphysalis longicornis is a blood-feeding hard tick known for transmitting a variety of pathogens, including Babesia. How the parasites in the imbibed blood become anchored in the midgut of ticks is still unknown. Leucine-rich repeat domain (LRR)-containing protein, which is associated with the innate immune reaction and conserved in many species, has been detected in H. longicornis and has previously been indicated in inhibiting the growth of Babesia gibsoni. However, the detailed mechanism is unknown. In this study, one of the ligands for LRR from H. longicornis (HlLRR) was identified in Babesia microti, designated BmActin, using glutathione transferase (GST) pulldown experiments and immunofluorescence assays. Moreover, RNA interference of HlLRR led to a decrease in the BmActin mRNA expression in the midgut of fully engorged ticks which fed on B. microti-infected mice. We also found that the expression level of the innate immune molecules in H. longicornis, defensin, antimicrobial peptides (AMPs), and lysozyme, were downregulated after the knockdown of HlLRR. However, subolesin expression was upregulated. These results indicate that HlLRR not only recognizes BmActin but may also modulate innate immunity in ticks to influence Babesia growth, which will further benefit the development of anti-Babesia vaccines or drugs.

BACKGROUND:Schistosomiasis japonica is an infectious disease caused by Schistosoma japonicum that seriously endangers human health. Domestic animals have important roles in disease transmission and goats are considered a primary reservoir host and source of infection. The prevalence and intensity of schistosomiasis infections have significantly decreased in China, and a more sensitive, specific detection method is urgently needed. The aim of this study was to develop a real-time PCR assay for accurate detection of S. japonicum infection in goats. METHODS:A real-time PCR method for detecting schistosomiasis japonica in goats was developed by amplification of a specific S. japonicum DNA fragment, and validated using a total of 94 negative and 159 positive plasma and serum samples collected in our previous study of S. japonicum infection. Both plasma and serum samples were evaluated by real-time PCR and enzyme-linked immunosorbent assay (ELISA). In addition, 120 goat plasma samples from an S. japonicum-endemic area (Wangjiang) and 33 from a non-endemic region (Weihai) were collected and evaluated using our method. RESULTS:The sensitivity and specificity of the real-time PCR for detecting infected samples were 98.74% (157/159, 95% CI: 95.53-99.85%) and 100% (94/94, 95% CI: 96.15-100%), respectively. For the ELISA, sensitivity and specificity were 98.11% (156/159, 95% CI: 94.59-99.61%) and 90.43% (85/94, 95% CI: 82.60-95.53%), respectively. Further, we found positivity rates for S. japonicum infection in Wangjiang and Weihai of 8.33% (10/120, 95% CI: 4.07-14.79%) and 0% (0/33, 95% CI: 0-10.58%), respectively. CONCLUSIONS:The results of this study indicate that our real-time PCR method exhibits higher sensitivity and specificity than ELISA and is a useful method for detection of S. japonicum infection in goats.

蜱是遍布于全世界的外部吸血寄生虫,其种类丰富、宿主广泛、生存生殖力强,给其周围的人和动物的健康带来了很大威胁.为了了解上海市警犬体表的蜱的种类及其携带的微生物和原虫,本研究对收集的蜱种进行了形态学和分子生物学鉴定,并对蜱携带的寄生虫和微生物种群,分别进行了套式PCR和16S rRNA扩增子测序和分析.结果表明,上海市警犬体表获得的蜱为血红扇头蜱(Rhipicephalus sanguineus),雌蜱携带的常见蜱传原虫为犬巴贝斯虫(Babesia canis),且雌、雄蜱体内均未检出泰勒虫;雌、雄蜱携带的病原微生物是柯克斯体(Coxiella)(分别占比为2.9％、0.4％)和布鲁氏杆菌(Brucella)(分别占比1.0％、3.1％).本研究结果为上海的蜱及蜱传病的防治提供了警示信息.