Progress of researches on traveler’s diarrhea caused by parasitic infections / 中国血吸虫病防治杂志

With the rapid development of global tourism, traveling gradually becomes an important part of daily lives, and travelers’health is paid more and more attention. Traveler’s diarrhea (TD) is one of the most common diseases among international or trans-regional travelers, which causes great disease and economic burdens. Currently, there is still a lack of systematic studies on the correlation between parasites and TD. The review mainly summarizes intestinal protozoa and helminth infections among patients with TD, so as to provide insights into the development of the control measures for parasitic diseases associated with TD and the prevention of risk factors before the journey to and during the journey of the areas endemic for parasitic diseases.

Quantitative Microbial Risk Assessment of / 生物医学与环境科学（英文）

We aimed to assess the risks of

Screening and bioinformatic analysis of trehalase in Thelazia callipaeda / 中国血吸虫病防治杂志

Objective To characterize the trehalase gene in Thelazia callipaeda through screening the annotated data of the T. callipaeda genome, and to investigate the biological characteristics of the trehalase gene-coding protein. Methods The trehalase gene was screened from the T. callipaeda genome and subjected to validation by using a PCR assay. The structural features of the coding protein were analyzed with bioinformatics tools, including hydrophobicity, transmembrane region, signal peptides, conserved domains, as well as the secondary and tertiary structures and the antigen epitope. Homology analysis of the amino acid sequences was performed, and the phylogenetic tree was built by the MEGA X software. In addition, the protein-protein interaction network was deduced from the STRING database. Results The sequence of the trehalase gene with the complete CDS region was obtained from T. callipaeda genome, which had a length of 1 638 bp and encoded 545 amino acids. The encoded protein was predicted to have a molecular weight of 63 478.48 ku and be a secretory protein. The 5′ domain of the encoded protein contained a signal peptide without transmembrane regions, and was predicted to contain 7 antigen epitopes. Based on the protein-protein interaction network of nematodes in the STRING database, the protein-protein interaction network of the trehalase gene of T. callipaeda was deduced, and 27 interactions covering 10 genes were identified. Conclusions A trehalase gene is successfully identified in T. callipaeda genome and its coding protein receives a bioinformatics analysis, which provides insights into the research on the biological functions of the protein and the screening of vaccine candidates for thelaziasis callipaeda.

[Comparison of efficiency of Kato-Katz technique and PCR assay for detecting Clonorchis sinensis infection].

OBJECTIVE: To compare the performance of modified Kato-Katz thick smear method (KK method) and PCR assay in field detection of Clonorchis sinensis in human fecal samples, which provides insight into the selection of tools for detecting C. sinensis. METHODS: Based on the epidemiological investigation of human C. sinensis infections in Tengxian County of Guangxi Zhuang Autonomous Region in 2016, a total of 133 fecal samples were randomly selected and stored at -20 ℃. All fecal samples were detected for C. sinensis infection using KK method and PCR assay, and the detection rate was compared between the two techniques. In addition, Kappa test was used to evaluate the consistency between the two methods. RESULTS: Among all fecal samples, the overall detection rate of C. sinensis was 77.44% (103/133), and the detection rate was significantly higher by PCR assay (70.68%, 93/133) than by KK method (57.14%, 76/133) (χ2 = 26.15, P < 0.01). There were 88.16% (67/76) of the microscopy-positive fecal samples positive for PCR assay, and 47.37% (27/57) of the microscopy-negative fecal samples positive for PCR assay. The detection rate of C. sinensis by PCR assay (94.74%, 18/19) was higher in fecal samples with EPG of > 1 000 than in samples with EPG of < 1 000 (85.96%, 49/57) (χ2 = 1.05, P = 0.436). The consistency of the detection rate of C. sinensis was moderate between the KK method and PCR assay (Kappa = 0.73). CONCLUSIONS: The detection rate of C. sinensis by PCR assay is significantly higher than by KK method. In low-endemic areas of C. sinensis infections, the combination of KK method and PCR assay is suggested, so as to improve the detection rate.

[Progress of research on the interplay between helminth and intestinal protozoa and gut microbiota].

As the largest and most complex ecosystem in humans, gut microbiota resides in human or animal gastrointestinal tract with intestinal viruses and parasites. Previous studies have demonstrated that gut microbiotadysbiosis is strongly correlated with the development, progression and prognosis of multiple diseases. The parasites that are colonized in the host, may directly or indirectly affect gut microbiota and the gut microbiota-host homeostasis, and changes in the composition and diversity of gut microbiota may also affect parasitic infections and the development, progression and prognosis of parasitic diseases. This paper reviews the progress of research on the interplay between helminth and intestinal protozoa and gut microbiota.

Dynamic changes of myeloid-derived suppressor cells and regulatory T cells in livers of mice infected with Echinococcus granulosus / 中国血吸虫病防治杂志

Objective To investigate the dynamics changes of the myeloid-derived suppressor cells (MDSCs) and regulatory T (Treg) cells in mice infected with Echinococcus granulosus and explore the possible biological significance. Methods Thirty female BALB/c mice of 6 weeks old were randomly divided into the infection and control groups, of 15 mice in each group. Mice in the infection group were intraperitoneally injected with 2 000 E. granulosus protoscoleces, while those in the control group were injected with the same volume of physiological saline. Mouse liver white blood cells were harvested 3 (early stage), 6 (medium stage) and 12 months (late stage) post-infection, and the proportions of MDSCs, their subpopulations (M-MDSCs and PMN-MDSCs) and Treg cells were assessed by flow cytometry. Results The proportions of MDSCs were (1.61 ± 0.36)%, (5.68 ± 0.69)% and (16.18 ± 0.69)% in mouse liver white blood cells in the infection group 3, 6 and 12 months post-infection with E. granulosus, and (2.19 ± 0.42)%, (0.99 ± 0.07) % and (4.18 ± 0.84)% in the control group, and there were significant differences in the proportion of the MDSCs in mouse liver white blood cells between the infection and control groups 6 and 12 months post-infection (P < 0.01). The proportions of M-MDSCs were (0.69 ± 0.27)%, (5.30 ± 0.72)% and (10.75 ± 0.29)% in mouse liver white blood cells in the infection group 3, 6 and 12 months post-infection, and (0.42 ± 0.24)%, (0.69 ± 0.02)% and (2.12 ± 0.13)% in the control group, and there were significant differences in the proportion of the M-MDSCs in the mouse liver white blood cells between the infection and control groups 6 and 12 months post-infection (P < 0.01). The proportions of PMN-MDSCs were (0.93 ± 0.23)%, (0.32 ± 0.02)% and (5.14 ± 1.03)% in mouse liver white blood cells in the infection group 3, 6 and 12 months post-infection, and (1.77 ± 0.26)%, (0.28 ± 0.05)% and (1.99 ± 0.90)% in the control group, and there were significant differences in the proportion of PMN-MDSCs in mouse liver white blood cells between the infection and control groups 3 and 12 months post-infection (P < 0.05). The proportions of Treg cells were (3.35 ± 0.14)%, (6.24 ± 0.38)% and (3.41 ± 0.07)% in mouse liver white blood cells in the infection group 3, 6 and 12 months post-infection, and (3.48 ± 0.46)%, (3.65 ± 0.45)% and (3.12 ± 0.12)% in the control group, and there were significant differences in the proportion of Treg cells in mouse liver white blood cells between the infection and control groups 6 and 12 months post-infection (P < 0.01). Conclusions The percentages of both MDSCs and Treg cells increase in mouse liver white blood cells 6 and 12 months post-infection with E. granulosus, and a more remarkable increase is seen in the percentage of MDSCs, which is mainly found in M-MDSCs. These findings suggest that M-MDSCs may play a major immunosuppressive role in the medium and late stages of E. granulosus infection in mice.

Comparison of efficiency of Kato-Katz technique and PCR assay for detecting Clonorchis sinensis infection / 中国血吸虫病防治杂志

Objective To compare the performance of modified Kato-Katz thick smear method (KK method) and PCR assay in field detection of Clonorchis sinensis in human fecal samples, which provides insight into the selection of tools for detecting C. sinensis. Methods Based on the epidemiological investigation of human C. sinensis infections in Tengxian County of Guangxi Zhuang Autonomous Region in 2016, a total of 133 fecal samples were randomly selected and stored at -20 ℃. All fecal samples were detected for C. sinensis infection using KK method and PCR assay, and the detection rate was compared between the two techniques. In addition, Kappa test was used to evaluate the consistency between the two methods. Results Among all fecal samples, the overall detection rate of C. sinensis was 77.44% (103/133), and the detection rate was significantly higher by PCR assay (70.68%, 93/133) than by KK method (57.14%, 76/133) (χ2 = 26.15, P < 0.01). There were 88.16% (67/76) of the microscopy-positive fecal samples positive for PCR assay, and 47.37% (27/57) of the microscopy-negative fecal samples positive for PCR assay. The detection rate of C. sinensis by PCR assay (94.74%, 18/19) was higher in fecal samples with EPG of > 1 000 than in samples with EPG of < 1 000 (85.96%, 49/57) (χ2 = 1.05, P = 0.436). The consistency of the detection rate of C. sinensis was moderate between the KK method and PCR assay (Kappa = 0.73). Conclusions The detection rate of C. sinensis by PCR assay is significantly higher than by KK method. In low-endemic areas of C. sinensis infections, the combination of KK method and PCR assay is suggested, so as to improve the detection rate.

Comparison of efficiency of Kato-Katz technique and PCR assay for detecting Clonorchis sinensis infection / 中国血吸虫病防治杂志

Objective To compare the performance of modified Kato-Katz thick smear method (KK method) and PCR assay in field detection of Clonorchis sinensis in human fecal samples, which provides insight into the selection of tools for detecting C. sinensis. Methods Based on the epidemiological investigation of human C. sinensis infections in Tengxian County of Guangxi Zhuang Autonomous Region in 2016, a total of 133 fecal samples were randomly selected and stored at -20 ℃. All fecal samples were detected for C. sinensis infection using KK method and PCR assay, and the detection rate was compared between the two techniques. In addition, Kappa test was used to evaluate the consistency between the two methods. Results Among all fecal samples, the overall detection rate of C. sinensis was 77.44% (103/133), and the detection rate was significantly higher by PCR assay (70.68%, 93/133) than by KK method (57.14%, 76/133) (χ2 = 26.15, P < 0.01). There were 88.16% (67/76) of the microscopy-positive fecal samples positive for PCR assay, and 47.37% (27/57) of the microscopy-negative fecal samples positive for PCR assay. The detection rate of C. sinensis by PCR assay (94.74%, 18/19) was higher in fecal samples with EPG of > 1 000 than in samples with EPG of < 1 000 (85.96%, 49/57) (χ2 = 1.05, P = 0.436). The consistency of the detection rate of C. sinensis was moderate between the KK method and PCR assay (Kappa = 0.73). Conclusions The detection rate of C. sinensis by PCR assay is significantly higher than by KK method. In low-endemic areas of C. sinensis infections, the combination of KK method and PCR assay is suggested, so as to improve the detection rate.

Dynamic changes of myeloid-derived suppressor cells and regulatory T cells in livers of mice infected with Echinococcus granulosus / 中国血吸虫病防治杂志

Objective To investigate the dynamics changes of the myeloid-derived suppressor cells (MDSCs) and regulatory T (Treg) cells in mice infected with Echinococcus granulosus and explore the possible biological significance. Methods Thirty female BALB/c mice of 6 weeks old were randomly divided into the infection and control groups, of 15 mice in each group. Mice in the infection group were intraperitoneally injected with 2 000 E. granulosus protoscoleces, while those in the control group were injected with the same volume of physiological saline. Mouse liver white blood cells were harvested 3 (early stage), 6 (medium stage) and 12 months (late stage) post-infection, and the proportions of MDSCs, their subpopulations (M-MDSCs and PMN-MDSCs) and Treg cells were assessed by flow cytometry. Results The proportions of MDSCs were (1.61 ± 0.36)%, (5.68 ± 0.69)% and (16.18 ± 0.69)% in mouse liver white blood cells in the infection group 3, 6 and 12 months post-infection with E. granulosus, and (2.19 ± 0.42)%, (0.99 ± 0.07) % and (4.18 ± 0.84)% in the control group, and there were significant differences in the proportion of the MDSCs in mouse liver white blood cells between the infection and control groups 6 and 12 months post-infection (P < 0.01). The proportions of M-MDSCs were (0.69 ± 0.27)%, (5.30 ± 0.72)% and (10.75 ± 0.29)% in mouse liver white blood cells in the infection group 3, 6 and 12 months post-infection, and (0.42 ± 0.24)%, (0.69 ± 0.02)% and (2.12 ± 0.13)% in the control group, and there were significant differences in the proportion of the M-MDSCs in the mouse liver white blood cells between the infection and control groups 6 and 12 months post-infection (P < 0.01). The proportions of PMN-MDSCs were (0.93 ± 0.23)%, (0.32 ± 0.02)% and (5.14 ± 1.03)% in mouse liver white blood cells in the infection group 3, 6 and 12 months post-infection, and (1.77 ± 0.26)%, (0.28 ± 0.05)% and (1.99 ± 0.90)% in the control group, and there were significant differences in the proportion of PMN-MDSCs in mouse liver white blood cells between the infection and control groups 3 and 12 months post-infection (P < 0.05). The proportions of Treg cells were (3.35 ± 0.14)%, (6.24 ± 0.38)% and (3.41 ± 0.07)% in mouse liver white blood cells in the infection group 3, 6 and 12 months post-infection, and (3.48 ± 0.46)%, (3.65 ± 0.45)% and (3.12 ± 0.12)% in the control group, and there were significant differences in the proportion of Treg cells in mouse liver white blood cells between the infection and control groups 6 and 12 months post-infection (P < 0.01). Conclusions The percentages of both MDSCs and Treg cells increase in mouse liver white blood cells 6 and 12 months post-infection with E. granulosus, and a more remarkable increase is seen in the percentage of MDSCs, which is mainly found in M-MDSCs. These findings suggest that M-MDSCs may play a major immunosuppressive role in the medium and late stages of E. granulosus infection in mice.

Progress of research on the interplay between helminth and intestinal protozoa and gut microbiota / 中国血吸虫病防治杂志

As the largest and most complex ecosystem in humans, gut microbiota resides in human or animal gastrointestinal tract with intestinal viruses and parasites. Previous studies have demonstrated that gut microbiotadysbiosis is strongly correlated with the development, progression and prognosis of multiple diseases. The parasites that are colonized in the host, may directly or indirectly affect gut microbiota and the gut microbiota-host homeostasis, and changes in the composition and diversity of gut microbiota may also affect parasitic infections and the development, progression and prognosis of parasitic diseases. This paper reviews the progress of research on the interplay between helminth and intestinal protozoa and gut microbiota.

[Genetic variation of Thelazia callipaeda among isolates collected from patients in Zunyi City, Guizhou Province].

OBJECTIVE: To identify the genetic variation and possible sources of Thelazia callipaeda isolates collected from patients in Zunyi City, Guizhou Province. METHODS: Seven cases of T. callipaeda infection in Zunyi City, 2016 were verified, and DNA (s) were extracted from the T. callipaeda's body collected from the thelaziasis patients. A mitochondrial COX1 fragment was amplified and sequenced. The sequence alignment and phylogenetical analysis were performed to compare the genetic variation of the gene sequence with the homologous sequences downloaded from Genebank. RESULTS: COX1 genes of T. callipaeda were differed among the samples from the seven cases, which had low variation. CONCLUSIONS: Zunyi City is a new area with endemic of thelaziasis. The isolates from Zunyi City include either Asian origin or European origin of T. callipaeda. Moreover, at least four haplotypes are identified among the seven isolates.

[In vitro pro - angiogenic activity of Echinococcus granulosus hydatid cysts from experimentally infected mice].

OBJECTIVE: To preliminarily study the pro-angiogenic activity of Echinococcus granulosus hydatid cysts against human umbilical vein endothelial cells in vitro and the transcriptional level of potential pro-angiogenic factors. METHODS: The hydatid cysts and protoscolex derived from experimentally infected mice were collected and cultured in vitro, then the human umbilical vein endothelial cells were stimulated by the supernatant and cyst fluid respectively, and the angiogenesis was observed and analyzed through a microscope and the angiogenesis mode of the software NIH Image J. Meanwhile, the mouse homologous proteins of matrix metalloproteinase-9 (MMP-9) and high mobility group box B1 (HMGB1) were identified in E. granulosus genome through sequence alignment, and their transcriptional levels in the cyst wall and protoscolex were analyzed. RESULTS: The culture supernatant of hydatid cysts significantly promoted human umbilical vein endothelial cells into tubes (F = 73.03, P < 0.001), the transcriptions of MMP-9 and HMGB1 were detected in the cyst wall and protoscolex, and the transcriptional level of MMP-9 was higher in protoscolex (t = -11.65, P < 0.001), while the level of HMGB1 was higher in hydatid cysts (t = 6.43, P = 0.003). CONCLUSIONS: Some parasite-derived pro-angiogenic molecules may exist in the supernatant of E. granulosus hydatid cysts, while further researches are required into their exact mechanisms.

[Changes and significance of inflammatory cytokines in sera of mice chronically infected with larvae of Echinococcus granulosus].

OBJECTIVE: To investigate the levels of cytokines in the sera of mice chronically infected with the larvae of Echinococcus granulosus, and explore the mechanisms of immune regulation against parasite infection. METHODS: The protoscoleces were isolated from the livers and lungs of sheep infected with E. granulosus, and then inoculated intraperitoneally to BALB/c mice (2 000 for each mouse), to establish the mouse model of E. granulosus infection. The mice in the control group were injected intraperitoneally with an equal volume of PBS. The sera of both control and infected mice were collected to test the levels of multiple cytokines by using the Cytometric Bead Array (CBA) 5 months post-infection. RESULTS: In contrast to the control group, the multiple cysts were found in the abdominal cavity, livers and lungs of the infected mice. Moreover, the levels of inflammatory cytokines such as IL-17A, IL-6, IFN-γ, MCP-1, IL-12P70 and TNF-α in the sera of the infected mice were significantly higher than those in the control group (t = 2.713-9.255, all P < 0.05) while the levels of anti-inflammatory cytokine IL-10 were elevated post-infection (t = 3.936, P < 0.001). CONCLUSIONS: Higher inflammatory cytokines in the mice chronically infected with the larvae of E. granulosus, may benefit for the limitation of parasite growth.

Age-related infection with Cryptosporidium species and genotype in pigs in China / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>Pigs, as hosts of zoonotic Cryptosporidium species/genotypes, are domestic animals with public health significance. The present study was to characterize the infection rate and species/genotype of Cryptosporidium in pre-weaned and post-weaned pigs from Shanghai and Shaoxing, China.</p><p><b>METHODS</b>A total of 208 fecal samples (42 from pre-weaned piglets, and 166 from post-weaned pigs) were examined by nested PCR of the 18S rRNA gene and analyzed by phylogenetic DNA fragment sequencing of secondary PCR products.</p><p><b>RESULTS</b>Infection was detected in 79 samples (19/42 pre-weaned piglets, and 60/166 post-weaned pigs). C. suis (14/79) and Cryptosporidium pig genotype II (65/79) were identified; piglets were more susceptible to the former (13/14) and post-weaned pigs to the latter (59/65).</p><p><b>CONCLUSION</b>Infection of Cryptosporidium spp. in pigs was age-specific; piglets were more susceptible to C. suis while pigs were more susceptible to Cryptosporidium pig genotype II. These findings combined with the isolation of the two Cryptosporidium from water suggest that pigs may be a source of zoonotic Cryptosporidium water pollution. Improvements in pig feeding practices, sewage discharge, feces disposal and field worker protection are therefore important to prevent potential public health problems.</p>