Major emerging and re-emerging zoonoses in China: a matter of global health and socioeconomic development for 1.3 billion

SummaryEmerging and re-emerging zoonoses are a significant public health concern and cause considerable socioeconomic problems globally. The emergence of severe acute respiratory syndrome (SARS), highly pathogenic avian influenza (HPAI) H5N1, avian influenza H7N9, and severe fever with thrombocytopenia syndrome (SFTS), and the re-emergence of rabies, brucellosis, and other zoonoses have had a significant effect on the national economy and public health in China, and have affected other countries. Contributing factors that continue to affect emerging and re-emerging zoonoses in China include social and environmental factors and microbial evolution, such as population growth, urbanization, deforestation, livestock production, food safety, climate change, and pathogen mutation. The Chinese government has devised new strategies and has taken measures to deal with the challenges of these diseases, including the issuing of laws and regulations, establishment of disease reporting systems, implementation of special projects for major infectious diseases, interdisciplinary and international cooperation, exotic disease surveillance, and health education. These strategies and measures can serve as models for the surveillance and response to continuing threats from emerging and re-emerging zoonoses in other countries

Metabolic footprinting of extracellular metabolites of brain endothelium infected with Neospora caninum in vitro

BACKGROUND: The survival of the intracellular protozoan parasite Neospora caninum depends on its ability to adapt to changing metabolic conditions of the host cell. Thus, defining cellular and metabolic changes in affected target tissues may aid in delineating pathogenetic mechanism. We undertook this study to assess the metabolic response of human brain microvascular endothelial cells (HBMECs) to N. caninum infection in vitro. METHODS: HBMECs were exposed to N. caninum infection and the cytotoxic effects of infection were analyzed by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazoliumbromidin (MTT) assay and lactate dehydrogenase (LDH) release assay. Metabolic footprinting of the extracellular metabolites of parasite-infected and non-infected culture supernatant was determined by using targeted (Randox RX Imola clinical chemistry analyser) and unbiased RS (Raman microspectroscopy) approaches. RESULTS: The MTT assay did not reveal any cytotoxic effect of N. caninum challenge on host cell viability. Measurement of LDH activity showed that N. caninum significantly induced loss of cell membrane integrity in a time-dependent and dose-dependent manner compared to control cells. Targeted biochemical analysis revealed that beta hydroxybutyrate, pyruvate, ATP, total protein, non-esterified fatty acids, and triglycerides are significantly different in infected cells compared to controls. RS-based footprinting with principal component analysis (PCA) were able to correctly distinguish extracellular metabolites obtained from infected and control cultures, and revealed infection-related spectral signatures at 865 cm(−1), 984 cm(−1), 1046 cm(−1), and 1420 cm(−1), which are attributed to variations in the content of lipids and nucleic acids in infected cultures. CONCLUSIONS: The changing pattern of extracellular metabolites suggests that HBMECs are target of metabolic alterations in N. caninum infection, which seem to reflect the changing metabolic state of infected cells and constitute a level of information exchange that host and parasite use to coordinate activities

Transcriptome Profiling of Toxoplasma gondii-Infected Human Cerebromicrovascular Endothelial Cell Response to Treatment with Monensin

Central to the progression of cerebral toxoplasmosis is the interaction of Toxoplasma gondii with the blood-brain barrier (BBB) endothelial cells. In the present work, we tested the hypothesis that inhibition of Wnt pathway signalling by the monovalent ionophore monensin reduces the growth of T. gondii infecting human brain microvascular endothelial cells (hBMECs) or microglial cells. The anti-parasitic effect of monensin (a Wnt signalling inhibitor) on the in vitro growth of T. gondii tachyzoites was investigated using two methods (Sulforhodamine B staining and microscopic parasite counting). The monensin inhibited T. gondii growth (50% inhibitory concentration [IC 50 ] = 0.61 µM) with a selective index = 8.48 when tested against hBMECs (50% cytotoxic concentration [CC 50 ] = 5.17 µM). However, IC 50 of monensin was 4.13 µM with a SI = 13.82 when tested against microglia cells (CC 50 = 57.08 µM), suggesting less sensitivity of microglia cells to monensin treatment. The effect of T. gondii on the integrity of the BBB was assessed by the transendothelial electrical resistance (TEER) assay using an in vitro human BBB model. The results showed that T. gondii infection significantly decreased hBMECs' TEER resistance, which was rescued when cells were treated with 0.1 µM monensin, probably due to the anti-parasitic activity of monensin. We also investigated the host-targeted effects of 0.1 µM monensin on global gene expression in hBMECs with or without T. gondii infection. Treatment of hBMECs with monensin did not significantly influence the expression of genes involved in the Wnt signalling pathway, suggesting that although inhibition of the Wnt signalling pathway did not play a significant role in T. gondii infection of hBMECs, monensin was still effective in limiting the growth of T. gondii. On the contrary, monensin treatment downregulated pathways related to steroids, cholesterol and protein biosynthesis and their transport between endoplasmic reticulum and Golgi apparatus, and deregulated pathways related to cell cycle and DNA synthesis and repair mechanisms. These results provide new insight into the host-modulatory effect of monensin during T. gondii infection, which merits further investigation

In vitro activity of Camellia sinensis (green tea) against trophozoites and cysts of Acanthamoeba castellanii

© 2020 The Author(s) The effect of Camellia sinensis (green tea) on the growth of Acanthamoeba castellanii trophozoites was examined using a microplate based-Sulforhodamine B (SRB) assay. C. sinensis hot and cold brews at 75% and 100% concentrations significantly inhibited the growth of trophozoites. We also examined the structural alterations in C. sinensis-treated trophozoites using transmission electron microscopy (TEM) and scanning electron microscopy (SEM). This analysis showed that C. sinensis compromised the cell membrane integrity and caused progressive destruction of trophozoites. C. sinensis also significantly inhibited the parasite's ability to form cysts in a dose-dependent manner and reduced the rate of excystation from cysts to trophozoites. C. sinensis exhibited low cytotoxic effects on primary corneal stromal cells. However, cytotoxicity was more pronounced in SV40-immortalized corneal epithelial cells. Chromatographic analysis showed that both hot and cold C. sinensis brews contained the same number and type of chemical compounds. This work demonstrated that C. sinensis has anti-acanthamoebic activity against trophozoite and cystic forms of A. castellanii. Further studies are warranted to identify the exact substances in C. sinensis that have the most potent anti-acanthamoebic effect

Lipidomic analysis of serum from horses with strongyle infection

The development of techniques capable of accurate diagnosis of strongyle infections is at the forefront of research in equine parasitology. The aim of this study was to evaluate the potential, for using lipidomics in the diagnosis of strongyle infection. Blood and fecal samples were collected from 30 horses. Fecal egg count (FEC) results were used to select the serum samples from six uninfected horses (negative controls) and from the five horses with the highest burdens. The lipid portion of serum samples was extracted and analyzed using High Performance Liquid Chromatography-Mass Spectroscopy. The concentrations of 66 lipid metabolites differed between infected and uninfected horses (p<0.025). Database comparison of mass/charge (m/z) ratios and retention times were used to tentatively identify 16 of these metabolites. The roles of these metabolites and reasons for the observable changes were discussed. These results demonstrate the potential for the use of high resolution lipidomic analysis, for the development of a diagnostic technique capable of detecting, and perhaps stratifying, equine strongyle infection

The complete mitochondrial genomes for three Toxocara species of human and animal health significance

<p>Abstract</p> <p>Background</p> <p>Studying mitochondrial (mt) genomics has important implications for various fundamental areas, including mt biochemistry, physiology and molecular biology. In addition, mt genome sequences have provided useful markers for investigating population genetic structures, systematics and phylogenetics of organisms. <it>Toxocara canis, Toxocara cati </it>and <it>Toxocara malaysiensis </it>cause significant health problems in animals and humans. Although they are of importance in human and animal health, no information on the mt genomes for any of <it>Toxocara </it>species is available.</p> <p>Results</p> <p>The sizes of the entire mt genome are 14,322 bp for <it>T. canis</it>, 14029 bp for <it>T. cati </it>and 14266 bp for <it>T. malaysiensis</it>, respectively. These circular genomes are amongst the largest reported to date for all secernentean nematodes. Their relatively large sizes relate mainly to an increased length in the AT-rich region. The mt genomes of the three <it>Toxocara </it>species all encode 12 proteins, two ribosomal RNAs and 22 transfer RNA genes, but lack the ATP synthetase subunit 8 gene, which is consistent with all other species of Nematode studied to date, with the exception of <it>Trichinella spiralis</it>. All genes are transcribed in the same direction and have a nucleotide composition high in A and T, but low in G and C. The contents of A+T of the complete genomes are 68.57% for <it>T. canis</it>, 69.95% for <it>T. cati </it>and 68.86% for <it>T. malaysiensis</it>, among which the A+T for <it>T. canis </it>is the lowest among all nematodes studied to date. The AT bias had a significant effect on both the codon usage pattern and amino acid composition of proteins. The mt genome structures for three <it>Toxocara </it>species, including genes and non-coding regions, are in the same order as for <it>Ascaris suum </it>and <it>Anisakis simplex</it>, but differ from <it>Ancylostoma duodenale</it>, <it>Necator americanus </it>and <it>Caenorhabditis elegans </it>only in the location of the AT-rich region, whereas there are substantial differences when compared with <it>Onchocerca volvulus</it>,<it>Dirofiliria immitis </it>and <it>Strongyloides stercoralis</it>. Phylogenetic analyses based on concatenated amino acid sequences of 12 protein-coding genes revealed that the newly described species <it>T. malaysiensis </it>was more closely related to <it>T. cati </it>than to <it>T. canis</it>, consistent with results of a previous study using sequences of nuclear internal transcribed spacers as genetic markers.</p> <p>Conclusion</p> <p>The present study determined the complete mt genome sequences for three roundworms of human and animal health significance, which provides mtDNA evidence for the validity of <it>T. malaysiensis </it>and also provides a foundation for studying the systematics, population genetics and ecology of these and other nematodes of socio-economic importance.</p