Toxoplasma gondii is a single-celled parasite that infects nearly all warm-blooded animals, including humans (Montoya and Liesenfeld, 2004). It occurs worldwide and can persist for a lifetime in mammals. Humans get infected by eating undercooked meat of animals containing the tissue cysts of this parasite. In immune-competent individuals, T. gondii infection usually does not cause significant clinical symptoms, whereas in pregnant or immunocompromised individuals, T. gondii infection (toxoplasmosis) can cause more serious problems like abortion and even death (Dunn et al., 1999; Wang et al., 2017). A combination of pyrimethamine and sulfadiazine is usually used to treat toxoplasmosis, although it is generally inefficient and causes side effects (Alday and Doggett, 2017). Worse still, there is a lack of vaccines to prevent T. gondii infection in humans or animals.
Toxoplasma/enzymology* ; Animals ; Humans ; Toxoplasmosis ; Mitochondria/enzymology* ; Protozoan Proteins/metabolism*

To evaluate the immunogenicity and immunoprotective effects of a tRNA thiouridylase TgMnmA deletion strain of Toxoplasma gondii(T.gondii)on ICR mice,we constructed a mouse model immunized with RH△MnmA.Mice were immunized with 10 RH△MnmA tachyzoites by in-traperitoneal injection.After 30 d,indirect ELISA was used to detect the specific IgG antibody and its subtypes of immunized mice.Spleen lymphocyte suspension was prepared,and the splenic lym-phocyte subsets were analyzed by flow cytometry.Moreover,the relative expression level of cyto-kine mRNA was detected by real-time fluorescence quantitative PCR.After 30 d of immunization,mice were intraperitoneally inoculated with RH△ku80 tachyzoites.At 5 d post infection,the para-site load in the ascites,heart,liver and brain of mice was measured,and the survival of mice within 30 d after infection was observed and recorded.The results showed that compared with the control PBS group,RH△MnmA immunized group produced higher level of IgG and IgG2a antibodies,higher mRNA relative expression level of cytokines IL-2,IL-4,IL-6,IL-10,IL-12 and IFN-γ,and the number of CD4+and CD8a+in spleen lymphocytes also increased significantly.Mean-while,for the attack of RH△ku80 strain,the immune group can effectively reduce the parasite load in the ascites and some tissues,inhibit the reproduction of parasites In vivo,and significantly improve the survival rate of mice.The results of this study showed that the TgMnmA deletion strain of T.gondii can induce strong humoral and cellular immune responses in mice,and provide good immune protection against the infection of RHΔku80 strain,which has the potential to be-come a potentially promising live attenuated vaccine candidate against T.gondii.

Eimeria labbeana is a major pathogen of pigeon coccidiosis,causing damage to the intes-tinal epithelial cells of pigeons,which leads to gut injury,diarrhea,decreased production perform-ance,and even death.There have been no research on the pathogen characteristics of isolated strains in China.In this study,1 008 fecal samples were collected from nine cities in Zhejiang Prov-ince,including Hangzhou,Ningbo,Wenzhou,Shaoxing,Huzhou,Jinhua,Quzhou,Taizhou and Lishui.The samples were examined using the McMaster counting method to quantify oocysts per gram of feces,and coccidia species in positive samples were identified through microscopy.Patho-gens were isolated and purified with methods of single oocyst pickout under the microscopy and passage in coccidia-free pigeon,followed by a detailed study of their characteristics.Our findings demonstrated an overall infection rate of 55.8％(562/1 008)for pigeon coccidia in the surveyed ar-eas,with E.labbeana present across all farms.A strain of E.labbeana isolated from Zhejiang was successfully obtained and designated E.labbeana-ZJ.PCR identification and sequence alignment showed that this Zhejiang isolate shared a 99.67％similarity in the 18S rRNA gene sequence with the Australian strain(KT305927.1)and clustered into a small subgroup.Pathogenicity and oocyst shedding patterns were assessed through animal infection experiments,revealing a 4 days latent period,with peak infection occurring on the 8th day.Following infection,notable clinical symptoms emerged,with significant intestinal damage,and changes in body weight,indicating moderate path-ogenicity.The results enriched the epidemiological survey data of pigeon coccidiosis in China,and provide a new basis for further research and effective control measures against pigeon coccidiosis.

Eimeria labbeana is a major pathogen of pigeon coccidiosis,causing damage to the intes-tinal epithelial cells of pigeons,which leads to gut injury,diarrhea,decreased production perform-ance,and even death.There have been no research on the pathogen characteristics of isolated strains in China.In this study,1 008 fecal samples were collected from nine cities in Zhejiang Prov-ince,including Hangzhou,Ningbo,Wenzhou,Shaoxing,Huzhou,Jinhua,Quzhou,Taizhou and Lishui.The samples were examined using the McMaster counting method to quantify oocysts per gram of feces,and coccidia species in positive samples were identified through microscopy.Patho-gens were isolated and purified with methods of single oocyst pickout under the microscopy and passage in coccidia-free pigeon,followed by a detailed study of their characteristics.Our findings demonstrated an overall infection rate of 55.8％(562/1 008)for pigeon coccidia in the surveyed ar-eas,with E.labbeana present across all farms.A strain of E.labbeana isolated from Zhejiang was successfully obtained and designated E.labbeana-ZJ.PCR identification and sequence alignment showed that this Zhejiang isolate shared a 99.67％similarity in the 18S rRNA gene sequence with the Australian strain(KT305927.1)and clustered into a small subgroup.Pathogenicity and oocyst shedding patterns were assessed through animal infection experiments,revealing a 4 days latent period,with peak infection occurring on the 8th day.Following infection,notable clinical symptoms emerged,with significant intestinal damage,and changes in body weight,indicating moderate path-ogenicity.The results enriched the epidemiological survey data of pigeon coccidiosis in China,and provide a new basis for further research and effective control measures against pigeon coccidiosis.

To evaluate the immunogenicity and immunoprotective effects of a tRNA thiouridylase TgMnmA deletion strain of Toxoplasma gondii(T.gondii)on ICR mice,we constructed a mouse model immunized with RH△MnmA.Mice were immunized with 10 RH△MnmA tachyzoites by in-traperitoneal injection.After 30 d,indirect ELISA was used to detect the specific IgG antibody and its subtypes of immunized mice.Spleen lymphocyte suspension was prepared,and the splenic lym-phocyte subsets were analyzed by flow cytometry.Moreover,the relative expression level of cyto-kine mRNA was detected by real-time fluorescence quantitative PCR.After 30 d of immunization,mice were intraperitoneally inoculated with RH△ku80 tachyzoites.At 5 d post infection,the para-site load in the ascites,heart,liver and brain of mice was measured,and the survival of mice within 30 d after infection was observed and recorded.The results showed that compared with the control PBS group,RH△MnmA immunized group produced higher level of IgG and IgG2a antibodies,higher mRNA relative expression level of cytokines IL-2,IL-4,IL-6,IL-10,IL-12 and IFN-γ,and the number of CD4+and CD8a+in spleen lymphocytes also increased significantly.Mean-while,for the attack of RH△ku80 strain,the immune group can effectively reduce the parasite load in the ascites and some tissues,inhibit the reproduction of parasites In vivo,and significantly improve the survival rate of mice.The results of this study showed that the TgMnmA deletion strain of T.gondii can induce strong humoral and cellular immune responses in mice,and provide good immune protection against the infection of RHΔku80 strain,which has the potential to be-come a potentially promising live attenuated vaccine candidate against T.gondii.

Insulin-like peptides(ILPs)play a crucial role in the biological processes of nematode metabolism,signal transduction,and developmental processes,representing potential therapeutic targets for nematode infections in animals.In order to explore the specific role of ILPs in nematode development and infection,genome-wide identification,sequence and evolution analysis of the ILPs coding genes were conducted on Haemonchus contortus(H.contortus);transcriptional levels of these ILPs coding genes among developmental stages were determined by a real-time quantitative PCR method;recombinant ILPs were produced in prokaryotic system for polyclonal antibody prep-aration and Western blot analysis;indirect immunofluorescence localization experiment was used to reveal the tissue distribution of ILPs at different developmental stages.It was showed that the number of ILPs coding genes in H.contortus were significantly reduced compared with that of Caenorhabditis elegans,namely three members of ILPs coding genes exhibiting antagonistic fea-tures;the highest transcriptional levels of ILPs coding genes was detected in the infective third stage larvae of H.contortus;ILPs were found dominant in the intestine and hypodermis of the in-fective larvae of this parasitic nematode.In this study,three genes encoding antagonistic ILPs were identified in H.contortus,they might play a role in regulating the development and infection processes.The finding lay a foundation for the study of nematode hypobiosis(larval diapause)in animals and the screening of potential intervention targets.

Objective:To investigate the immunogenicity and safety of a boost dose of measles, mumps, and rubella combined vaccine (MMR) for children 4 to 6 years old.Methods:Children, aged 4 to 6 years old, had vaccinated with 1 dose of measles and rubella combined vaccine(MR) at the age of 8 months and 1 dose of MMR vaccine at 18-months, were recruited in Shanxi, Inner Mongolia, and Beijing, respectively. All children were assigned into 4, 5 and 6-year-old group. The children who met inclusion and exclusion criteria were vaccinated with 1 dose MMR vaccine, and were collected blood samples before vaccination and 35 to 42 d after the vaccination. During the study period, adverse events were collected at 30 min, 1 d, 2 d, 3 d, 4-12 d, and 13 to 42 days after vaccination. Serum was tested for IgG antibodies against measles, mumps and rubella. Geometric mean concentrations (GMC) of measles, mumps, and rubella antibodies were compared among groups by analysis of variance or non-parametric test. Seropositive rates and adverse event rates were compared among groups by Chi-square test or Fisher exact test.Results:A total of 500 children were included in immunogenicity analysis and 535 children were included in safety analysis. The overall adverse event rate was 20.37%, the most of severity for adverse events was mild. The rates of local and systemic adverse events were 0.37% and 20.00%, respectively. Symptoms of local adverse events were redness. The main systemic adverse events were fever, followed by cough, rash and runny nose. Received a dose of MMR vaccine for booster immunization, the seropositive rates of measles antibody, mumps antibody and rubella antibody were above 99% for all 3 age groups, and there was no significant difference between groups. There were significant differences in mumps antibody GMC among groups ( P=0.042), but no significant differences in measles and rubella antibodies GMC. Conclusion:The immunogenicity and safety of a boosted MMR vaccintion in children aged 4, 5 and 6 years were all similar good.

Objective By analyzing the epidemic characteristics and related indicators of SARS (2003) and COVID-19(2020), to explore the reasons for the similarities and differences of the two epidemics, so as to provide reference for epidemic prevention and control. Methods The general situation, clinical classification, activity history, contact history, family members’ contact and incidence of the two infectious diseases in Guangzhou were collected and used to analyze the time characteristics, occupational characteristics, age characteristics and other key indicators of the two diseases, including the number of cases, composition ratio (%), mean, median, crude mortality, etc. Results A total of 1 072 cases of SARS (2003) were included in the study. 353 of which were severe cases with the incidence of 30.13%. 43 cases of death were reported with a mortality rate of 4.01%. The average age was 46 years old, and 26.31% of the cases were medical staff. The interval time between first report to continuous zero reports was 129 days. As to COVID-19 (2020), a total of 346 cases were included. 58 of which were severe cases with the incidence of 16.67%. One case of death was reported with a mortality rate of 0.29%. The average age was 38 years old, and no hospital infection among medical staff was reported. The interval time between first report to continuous zero reports was 35 days. Conclusions The prevention and control strategies for COVID-19 (2010) are more effective compared to that of SARS (2003), and the emergency response procedures are worth to be evaluated and summarized.

BACKGROUND: Obtaining synovial fluid for diagnostic test of periprosthetic joint infection is invasive and painful to patients. Platelet count is a regular blood test which has been used as a possible predictor of several infectious diseases. Presumably, it could be one of the indicators of periprosthetic joint infection. OBJECTIVE: To identify the accuracies of platelet combined with white blood cell, erythrocyte sedimentation rate or C-reactive protein in the diagnosis of periprosthetic joint infection. METHODS: Patients undergoing revision arthroplasty from March 2013 to December 2018 in the First Affiliated Hospital of Guangzhou University of Chinese Medicine were retrospectively enrolled. A diagnosis of periprosthetic joint infection was confirmed in 77 patients according to the criterions from the Musculoskeletal Infection Society; the remaining 137 patients were confirmed as aseptic cases. White blood cell, erythrocyte sedimentation rate, or C-reactive protein and platelet count were compared between the two groups. The sensitivity, specificity, positive predictive value, and negative predictive value were calculated. RESULTS AND CONCLUSION: The platelet values were significantly increased in periprosthetic joint infection cases. Sensitivity and specificity of the platelet for periprosthetic joint infection were 64.94％ and 86.13％, respectively. Platelet demonstrated a higher accuracy when compared to erythrocyte sedimentation rate and C-reactive protein. In such cases, the platelet shows a certain reference value in confirming the diagnosis of periprosthetic joint infection. Platelet was enough used as adjunct diagnostic tool in patients suspected with periprosthetic joint infection.

Objective To explore the perinatal risk factors of early onset thrombocytopenia (EOT) in full-term small for gestational age infants. Methods A 1:1 or 1:2 matched case control study was carried out. A total of 93 full-term small for gestational age infants with EOT were selected from April 2008 to July 2014 as the case group, and the non EOT full-term small for gestational age infants with the birth weight difference <250 g and the gestational age difference <3 days were selected as the control group. The clinical data during perinatal period and laboratory examination results after admission were collected retrospectively. And the differences between the two groups were compared. Results The incidence of intrauterine distress (41.9％ vs. 25.8％, χ2=7.35, P=0.007), amniotic fluid contamination (39.8％ vs. 27％, χ2=4.66, P=0.031), and early-onset sepsis (39.8％ vs. 27％, χ2=4.66, P=0.031) were significantly higher in the case group than those in the control group. Conditional logistics regression analysis showed that intrauterine distress (β=0.60, OR=1.82, 95％CI=1.04～3.17, P=0.035) and early-onset sepsis (β=1.69, OR=5.44, 95％CI=1.11～26.76, P=0.037) were related to EOT. Conclusions Intrauterine distress and early-onset sepsis are risk factors for the onset of EOT in full-term small for gestational age infants.