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Objective To evaluate the immunoprotective effect of active immunization with recombinant peptidyl-prolyl cis-trans isomerase from Babesia microti against B. microti infection in mice. Methods Female BALB/c mice at 6 weeks of age, each weighing approximately 20 g, were divided into the recombinant protein immunization group, the infection control group and the normal control group, of 25, 18, 15 mice in each group, respectively. Mice in the recombinant protein immunization group were given active immunization with recombinant BmPPIase protein, and 18 mice with the highest antibody titers were intraperitoneally injected with 100 μL of B. microti-infected whole blood 2 weeks after the last immunization. Mice in the infection control group were intraperitoneally injected with 100 μL of B. microti-infected whole blood, while 15 mice in the normal control group received no treatment. Blood samples were collected from mice in the recombinant protein immunization group and the infection control group on days 0 to 30 post-immunization for detection of B. microti infection, and blood samples were collected on days 0, 7, 14, 21, and 28 post-immunization for routine blood tests with a blood cell analyzer and for detection of serum cytokines using cytometric bead array. Results Anti-BmPPIase antibodies were detected in 25 mice in the recombinant protein immunization group 2 weeks after the last immunization, with titers of 5 × 103 to 8 × 104. B. microti infection rate peaked in mice in both the recombinant protein immunization and the infection control group on day 7 post-immunization, with positive infection rates of 13.3% and 50.0%, and there were significant differences between the two groups in terms of B. microti infection rate on days 3 (χ2= 113.18, P < 0.01), 5 (χ2 = 475.22, P < 0.01), 7 (χ2 = 465.98, P < 0.01) and 9 post-infection (χ2= 18.71, P < 0.01), while the B. microti infection rate tended to be 0 in both groups on day 11 post-immunization. Routine blood tests showed higher red blood cell counts [(5.30 ± 0.50) × 1012 to (9.87 ± 0.24) × 1012 counts/L)] and hemoglobin levels [(89.67 ± 22.80) to (148.60 ± 3.05) g/L)] in the recombinant protein immunization group than in the infection control group on days 0 to 28 post-immunization. Cytometric bead array detected higher serum interferon-γ [(748.59 ± 17.56) to (3 858.28 ± 1 049.10) fg/mL], tumor necrosis factor-α [(6 687.34 ± 1 016.64) to (12 708.13 ± 1 629.79) fg/mL], interleukin (IL)-6 [(611.05 ± 75.60) to (6 852.68 ± 1 554.00) fg/mL] and IL-17a [(167.68 ± 185.00) to (10 849.27 ± 355.40) fg/mL] and lower IL-10 levels [(247.65 ± 138.00) to (18 787.20 ± 2 830.22) fg/mL] in the recombinant protein immunization group than in the infection control group during the study period. Conclusions Recombinant BmPPIase protein induces up-regulation of interferon-γ, tumor necrosis factor-α and presents a high immunoprotective activity against B. microti infection in mice, which is a potential vaccine candidate protein.
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Objective To investigate the prevalence and influencing factors of Blastocystis hominis infection among children with diarrhea under five years of age in Guangzhou City. Methods Children with diarrhea under 5 years of age admitted to Guangzhou Children’s hospital, Guangzhou Maternity and Child Healthcare Hospital and Guangzhou Women and Children’s Medical Center during the period between January 1 and December 31, 2020, were enrolled. Participants’ demographics, living environments and health status were collected using questionnaire surveys. Stool samples were collected from participants and nucleic acid was extracted. B. hominis infection was identified using PCR assay and sequence alignment, and the factors affecting B. hominis infection among children with diarrhea under 5 years of age were identified using univariate analysis and multivariate logistic regression analysis. Results A total of 684 children with diarrhea under 5 years of age were enrolled, including 468 male children and 216 female children, with a mean age of (1.79 ± 1.12) years. The overall prevalence of B. hominis infection was 4.97% [34/684, 95% confidential interval (CI): (3.59%, 6.86%)] among participants, and there was no significant difference in the prevalence of B. hominis infection between children with chronic [7.52% (20/266), 95% CI: (4.92%, 11.33%)] and acute diarrhea [3.35% (14/418), 95% CI: (2.01%, 5.54%)] (χ2 = 5.983, P = 0.014). Multivariate logistic regression analysis identified keeping pet [odds ratio (OR) = 6.298, 95% CI: (2.711, 14.633)], drinking non-tap water [OR = 4.522, 95% CI: (1.769, 11.561)], lactose intolerance [OR = 4.221, 95% CI: (1.043, 17.087)], antibiotic use [OR = 0.125, 95% CI: (0.017, 0.944)] and chronic diarrhea [OR = 2.172, 95% CI: (1.018, 4.637)] as factors affecting B. hominis infection among children with diarrhea under 5 years of age in Guangzhou City. Conclusions B. hominis infections is detected in children with diarrhea under five years of age in Guangzhou City. Improving home environments and pet-keeping hygiene is recommended to reduce the likelihood of B. hominis infection among children.
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Echinococcosis is a zoonotic parasitic disease caused by Echinococcus infections, and this disorder may cause fibrosis of multiple vital organs, which may further progress into cirrhosis. Early-stage hepatic fibrosis is reversible, and unraveling the mechanisms underlying hepatic fibrosis induced by Echinococcus infections is of great significance for the prevention and treatment of early-stage hepatic fibrosis. Recently, the studies pertaining to hepatic fibrosis associated with Echinococcus infections focus on cytokines and immune cells. This review summarizes the advances in the mechanisms underlying host immune cells- and cytokines-mediated hepatic fibrosis in humans or mice following Echinococcus infections.
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Objective To investigate the prognosis of two rare imported patients with human African trypanosomias (HAT) after treatment in a follow-up study, and to evaluate the therapeutic efficacy, so as to provide insights into the treatment of imported HAT patients. Methods The white blood cells in cerebrospinal fluid samples and the trypomastigotes in cerebrospinal fluid and blood samples were monitored in an imported case with Trypanosoma brucei rhodesiense infection 1, 3, 11 and 25 months post-treatment and in an imported case with T. brucei gambiense infection 1, 3, 8 and 12 months post-treatment to evaluate the therapeutic efficacy and prognosis. Results There were 1, 1, 4 and 2 white blood cells in per μL of cerebrospinal fluid in the case with T. brucei rhodesiense infection 1, 3, 11 and 25 months post-treatment, and there were 3, 6, 4 and 3 white blood cells in per μL of cerebrospinal fluid in the case with T. brucei gambiense infection 1, 3, 8 and 12 months post-treatment. In addition, no trypomastigotes were identified in the cerebrospinal fluid or blood samples of either case with T. brucei rhodesiense or T. brucei gambiense infection. Conclusion Following standardized treatment, two imported cases with human African trypanosomiasis cases recover satisfactorily, without any signs of relapse.
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Objective To establish a rapid nucleic acid detection technique for identification of Echinococcus multilocularis based on the recombinase aided isothermal amplification assay (RAA) and assess its diagnostic efficiency. Methods The mitochondrial gene sequence of E. multilocularis (GenBank accession number: AB018440) was used as a target sequence. The primers were designed according to the RAA reaction principle and synthesized, and RAA was performed using the generated primers. E. multilocularis genomic DNA at various concentrations and the pMD19-T (Simple) vector containing various copies of the target gene fragment were amplified using RAA to evaluate its sensitivity for detection of E. multilocularis, and RAA was em- ployed to detect the genomic DNA of E. granulosus G1 genotype, Taenia saginata, T. asiatica, T. multiceps, Dipylidium caninum, Toxocara canis, Trichuris trichiura, Giardia lamblia, Fasciola hepatica, Paragonimus westermani, Fasciola gigantica and Clonorchis sinensis to evaluate its specificity. In addition, the optimized RAA was employed to detect nine tissue specimens of E. granulosus-infected animals, 3 fecal samples from E. granulosus-infected dogs and 2 fecal samples from field infected dogs to examine its reliability and feasibility. Results The established RAA was able to detect the specific target gene fragment of E. multilocularis within 40 min. The lowest detect limit of RAA was 10 pg if E. multilocularis genomic DNA served as a template. If the re- combinant plasmid was used as a template, the minimally detectable copy number of RAA was 104. In addition, RAA was nega- tive for the genomic DNA of E. granulosus G1 genotype, T. saginata, T. asiatica, T. multiceps, D. caninum, T. canis, T. trichiura, G. lamblia, F. hepatica, P. westermani, F. gigantica and C. sinensis. The established RAA was positive for detection of the tissue specimens of infected animals, and simulated and field dog stool samples. Conclusion A rapid, sensitive and specific RAA is established, which shows promising values in identification of E. multilocularis and gene diagnosis of alveolar echinococcosis.
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Angiostrongyliasis is difficult to be diagnosed for the reason that no ideal method can be used. Serologic tests require specific equipment and are not always available in poverty-stricken zone and are time-consuming. A lateral flow immunoassay (LFIA) may be useful for angiostrongyliasis control. We established a LFIA for the diagnosis of angiostrongyliasis based on 2 monoclonal antibodies (mAbs) against antigens of Angiostrongylus cantonensis adults. The sensitivity and specificity were 91.1% and 100% in LFIA, while those of commercial ELISA kit was 97.8% and 86.3%, respectively. Youden index was 0.91 in LFIA and 0.84 in commercial ELISA kit. LFIA showed detection limit of 1 ng/ml of A. cantonensis ES antigens. This LFIA was simple, rapid, highly sensitive and specific, which opened an alternative approach for the diagnosis of human angiostrongyliasis.
Subject(s)
Adult , Humans , Angiostrongylus cantonensis , Angiostrongylus , Antibodies, Monoclonal , Diagnosis , Enzyme-Linked Immunosorbent Assay , Immunoassay , Limit of Detection , Methods , Sensitivity and Specificity , Serologic TestsABSTRACT
Objective The aim of the study was to investigate the epidemic situation,clinical symptom,diagnosis and epidemiological characteristics of human Fasciola gigantica infection in Dali,Yunnan province.It will also provide a scientific basis for fasciolosis control and prevention.Methods Epidemic data were collected and patient's clinical signs and symptoms were studied.Serum soluble antigen of Fasciola gigantica of patients and part of family members and health people in the same village was detected using enzyme-linked immunosorbent assay (ELISA) and the eggs of Fasciola gigantica in stool were observed under microscope.Sequencing and PCR amplification of Fasciola gigantica eggs had been done.Sequencing results were analyzed using basic local alignment search tool (BLAST) program of the U.S.National Center for Biotechnology Information (NCBI) and the similarity of the two in the sequence of nucleic acid was compared.Furthermore,patients were experimentally given orally therapeutic doses of Triclabendazole 10 mg·kg-1·d-1 daily for 2 days,and kept in the hospital for observation for one week.Moreover,host and vector were investigated in the surrounding ditches of Dali prefecture and Limnaea peregra snail samples were collected.All the snails were squashed by glass sheet in order to detect the cercarie.Cow dung and sheep manure was collected in the Limnaea peregra distribution environment,and the eggs in the feces were checked by microscope after washing and precipitation.Results All the 26 patients had a continued hyperpyrexia with distinct alimentary system symptoms of nausea,vomiting,stomachache,abdominal distension as well as hepatomegaly,sensitive to percussion,different levels of liver damage detected by CT.All the patients had an eaten history of raw Herba Houttuyniae and other aquatic plants,and the course of the disease was similar,with the same epidemiological characteristics.ELISA detection was used in the 26 patients,family members and other healthy population,the results of all the 26 patients were positive(100.0％,26/26) ; the positive rates of the 57 family members and other health people of the same village were 31.6％ (18/57) and 17.1％ (6/35),respectively.The results of sequencing and BLAST program showed that the pathogen was Fasciola gigantica with the similarity between 99％-100％.PCR amplification also confirmed that the eggs were Fasciola gigantica eggs with an approximately 1000 bp band on agarose gel.After treatment with Triclabendazole,body temperature of the patients dropped to normal and symptoms improved markedly.Moreover,329 Limnaea peregra snails were collected including 5 ones with redia and one-tailed cercariae which were preliminary identified as the larva of Fasciola gigantica.There were also eggs of Fasciola gigantica detected in one stool of cattle and one of goat.Conclusions Eating raw food is the leading cause of the onset of the disease.Triclabendazole is the drug of choice to treat Fasciolasis.Health education should be strengthened by government and disease prevention and control departments in order to make the local residents to understand the potential hazard of eating raw aquatic vegetable and drinking unboiled water,which is the key to prevent the occurrence of the disease.
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Objective To detect the rate of Angiostrongylus cantonensis infection and to study the effects of treatment so as to prepare monoclonal antibodies (McAbs) ,and gold immunochroma-tography assay (GICA) with 12D5 and 21B7 McAbs could be prepared in advance. Methods Two McAbs (12D5 and 21B7) were applied to detect the circulating antigen (CAg) in the sera of rats infected with A. cantonensis and angiostrongyliasis patients respectively by double antibody sandwich ELISA. Either 12D5 or 21B7 McAbs was used as antibody and protein A was conjugated with colloid gold as the detection marker. A special pad for GICA was designed according to the reaction procedure, and CAg were detected by GICA in the sera of rats infected with A. cantonensis and angiostrongyliasis patients respectively. Results 12D5 McAb was identified as IgG1 and 21B7 McAb was IgM. Results from Western blotting showed that two McAbs could be used to identified 55 KD protein of adult worms of A. cantonensis. The detection rates of CAg in the sera of infected rats was 100% (48/48) and the detection rates of CAg in the sera of angiostrongyliasis patients was 100% (32/32). No cross-reaction to sera of patients with other infection of parasites, such as clonochiasis, fasiolopsiasis, ancylostotniasis, ancylostomiasis, anisakiasis as well as schsitosomiasis wee seen and normal sera did not react with 12D5 and 21B7 McAbs. Conclusion Results from sandwich ELISA and GICA with 12D5 and 21B7 McAbs showed high specificity and acting as detecting CAg of A. cantonensis in sera of infected animals and patients. We noticed that GICA with 12D5 and 21B7 was not only rapid and simple that without requirement of special instrument, but also rather sensitive and specific for the detection of current infection with A.cantonensis.
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Objective To delimit the natural infectious focus, including the distribution of wildlife,species, ecology of intermediate hosts and final host of Angiostrongylus cantonensis, as well as the routes of transmission and epidemiological characteristics and wildlife of human Angiostrongylus cantonensis, based on human diverging cases identified in Shenzhen, southern area of China. Methods Data including rate of infection and density of Angiostrongylus cantonensis among different hosts in 12 different areas in Shenzhen was collected, using microscope to inspect homogenate liquids of snails. Wild mice were captured with mouse cage to examine the adult Angiostrongylus cantonensis. Using larva isolated from wild-snails-infected rats to observe the life cycle of Angiostrongylus cantonensis. Results Wild life of Angiostrongylus cantonensis existed in the southwest part of Shenzhen with its majority intermediate hosts as Achatina fulica. The overall rate of infection was 31% in wildlife and final host was found to be Rattus andersoni, Achatina fulica which were extensively distributed in the shrub region of Shenzhen because of suitable climate,humidity and vegetation for generating the life cycle of Achatina fulica. Human infected Angiostrongylus cantonensis was mainly due to eating raw snails or vegetables contaminated by larva of Angiostrongylus cantonensis.The peak of infection was seen from April to November in Shenzhen area.Conclusion Wildlife of Angiostrongylus cantonensis existed in the southwest part of Shenzhen with major wildlife reservoir including fresh water snail and wild mouse. The existence of natural focus Angiostrongylus cantonensis was now recognized as an important source of human angiostrongliasis in Shenzhen area.