Immunoprotective effect of recombinant peptidyl-prolyl cis-trans isomerase from Babesia microti against B. microti infection in mice / 中国血吸虫病防治杂志

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.

Effect of transfusing blood components containing Babesia microti on B. microti infection in BALB/c mice / 中国血吸虫病防治杂志

Objective To evaluate the effects of intravenous injection of different blood components containing Babesia microti on B. microti infection in mice. Methods Healthy mice were infected with B. microti, and then blood samples were collected from the mouse orbit to prepare whole blood, serum-free blood components and pure red blood cells containing B. microti. Twenty seven BALB/c mice were divided into three groups, including the whole blood group, the serum-free blood component group and the pure red blood cell group, of 9 mice in each group, and then, each group was divided into three subgroups, of 3 mice in each subgroup, which were injected with 100 μL of blood components containing B. microti at concentrations of 9.00, 0.90, 0.09 B. microti parasites/μL (900, 90, 9 B. microti parasites) via the tail vein, respectively. Blood samples were collected from the mouse tail tip every other day since one day post-injection to prepare thin blood smears. Following Giemsa staining of blood smears, B. microti infection was identified in red blood cells using microscopy. Results Following injection of 900 B. microti parasites, B. microti was identified in the peripheral blood in the whole blood group and the serum-free blood component group 3 days post-injection, and the density of B. microti parasites started to increase 15 days post-injection and peaked 21 days post-injection, with 2.21% and 1.76% rates of B. microti infection in red blood cells, respectively. Subsequently, the density of B. microti parasites declined, and the percentage of B. microti infection in red blood cells tended to be 0 31 days post-injection. During the study period, no B. microti was found in the peripheral blood in the pure red blood cell group. Following injection of 90 B. microti parasites, B. microti was identified in the peripheral blood in the whole blood group 3 days post-injection, and the density of B. microti parasites increased 15 days post-injection and peaked 21 days post-injection, with a 1.35% rate of B. microti infection in red blood cells, while the percentage of B. microti infection in red blood cells tended to be 0 31 days post-injection. During the study period, no B. microti was detected in the peripheral blood in the serum-free blood component group or the pure red blood cell group. Following injection of 9 B. microti parasites, no B. microti was detected in the peripheral blood in the whole blood group, the serum-free blood component group or the pure red blood cell group. Conclusion Blood components and dose of B. microti parasites may affect intravenous injection of B. microti injection in mice, and transfusion of blood components may case a risk of Babesia infection.

Effect of transfusing blood components containing Babesia microti on B. microti infection in BALB/c mice / 中国血吸虫病防治杂志

Objective To evaluate the effects of intravenous injection of different blood components containing Babesia microti on B. microti infection in mice. Methods Healthy mice were infected with B. microti, and then blood samples were collected from the mouse orbit to prepare whole blood, serum-free blood components and pure red blood cells containing B. microti. Twenty seven BALB/c mice were divided into three groups, including the whole blood group, the serum-free blood component group and the pure red blood cell group, of 9 mice in each group, and then, each group was divided into three subgroups, of 3 mice in each subgroup, which were injected with 100 μL of blood components containing B. microti at concentrations of 9.00, 0.90, 0.09 B. microti parasites/μL (900, 90, 9 B. microti parasites) via the tail vein, respectively. Blood samples were collected from the mouse tail tip every other day since one day post-injection to prepare thin blood smears. Following Giemsa staining of blood smears, B. microti infection was identified in red blood cells using microscopy. Results Following injection of 900 B. microti parasites, B. microti was identified in the peripheral blood in the whole blood group and the serum-free blood component group 3 days post-injection, and the density of B. microti parasites started to increase 15 days post-injection and peaked 21 days post-injection, with 2.21% and 1.76% rates of B. microti infection in red blood cells, respectively. Subsequently, the density of B. microti parasites declined, and the percentage of B. microti infection in red blood cells tended to be 0 31 days post-injection. During the study period, no B. microti was found in the peripheral blood in the pure red blood cell group. Following injection of 90 B. microti parasites, B. microti was identified in the peripheral blood in the whole blood group 3 days post-injection, and the density of B. microti parasites increased 15 days post-injection and peaked 21 days post-injection, with a 1.35% rate of B. microti infection in red blood cells, while the percentage of B. microti infection in red blood cells tended to be 0 31 days post-injection. During the study period, no B. microti was detected in the peripheral blood in the serum-free blood component group or the pure red blood cell group. Following injection of 9 B. microti parasites, no B. microti was detected in the peripheral blood in the whole blood group, the serum-free blood component group or the pure red blood cell group. Conclusion Blood components and dose of B. microti parasites may affect intravenous injection of B. microti injection in mice, and transfusion of blood components may case a risk of Babesia infection.

Dynamics of routine blood tests in BALB/c mice with Babesia microti infec-tion / 中国血吸虫病防治杂志

Objective To understand the changes in body weight,spleen weight and complete blood cells in BALB/c mice infected with Babesia microti.Methods For the infection group,six weeks old BALB/c mice were injected intraperitoneally with a dose of 100μL of B.microti infected blood(20％RBC infection rate,each mouse).For the determination of the progres-sion of B.microti infection up to 28 days of the infection,the microscopic visualization of thin blood smears of tail blood stained with Giemsa staining was performed in the infection group.The experiment was carried out at different intervals on days 0,7,14,21,and 28 after the infection,respectively.The mice were sacrificed,and spleens were collected and weighed,and the body weight of the mice was also determined.The blood cells of the mice were analyzed by using Mindray BC-5300 Vet animal automatic hematology analyzer.Results On the first day after the infection,B.microti was visualized in RBC of the infection group.The significantly highest infection rate(55％)appeared on the seventh day of the infection,and then steadily decreased;the mice attained the latent infection phase on the 28th day post-infection,when the parasite could not be visualized in the pe-ripheral blood.The mice in the infected group acquired a significantly lowest body weight on the 7th day of the infection,and then gradually returned to normal.The weight of the spleen was the significantly highest on the 14th day of the infection,and then consistently decreased.On the 28th day of infection,the spleen weight was still higher than that of the control group.There were no significant changes in the number of white blood cells(WBC),lymphocytes,and eosinophils in the infected mice;and altered levels were all within the normal mouse reference range.The number of red blood cells,hemoglobin,and platelet count in the infected mice were decreased to the lowest level when the B.microti infection rate achieved to the highest,and then gradu-ally returned to the normal levels.Conclusions B.microti infection can cause body weight loss,splenic weight gain,and re-duction in the number of erythrocytes and platelets in whole blood of the mice.Besides,the whole blood cell analyzer has a diag-nostic significance in the identification of babesiosis.

Two Imported Cases of Babesiosis with Complication or Co-Infection with Lyme Disease in Republic of Korea

Babesiosis, caused by Babesia microti and B. divergens, is transmitted by Ixodid ticks. Symptoms of babesiosis vary from a mild flu-like illness to acute, severe, and sometimes fatal and fulminant disease. In Korea, 7 imported babesiosis cases and 1 endemic case have been reported. We report 2 cases of severe babesiosis initially mistaken as malaria. The first patient was complicated by shock and splenic infarction, the other co-infected with Lyme disease. As the population traveling abroad increases every year, physicians should be aware of babesiosis which mimics malaria, co-infection with other diseases, and its complications.

Influence of liquid nitrogen cryopreservation to survive capability of Babesia microti standard strain / 中国人兽共患病学报

We discussed the influence of liquid nitrogen cryopreservation to survive capability of Babesia microti standard strain.The whole blood of mice infected with Babesia microti was put in liquid nitrogen to cryopreservation for 1 month,3 months,6 months,9 months,the whole blood was get out respectively and recovery at room temperature,and infected 3 mice respectively,100 μL/ mouse (the first generation after redissolution,the experiment group).In the same time,3 mice were also infected with Babesia microti as the animal conservation control group.When the infection rate was at a high level,the whole blood of the experiment group mice were injected into 3 normal BALB/c mice (the second generation after redissolution),to observe the changes of the Babesia microti form and proliferation situation,and also to observe the infection rate of the first and the second generation after redissolution in different conserving time.Compared with Babesia microti of animal subcultivation,the form of Babesia microti of liquid nitrogen cryopreservation changed a little.Small trophozoites,annular trophozoites,schizont and immature and mature merozoite and other form can also be seen.Compared with Babesia microti of animal subcultivation,the first time to see the worms and the time attaining to the high infection level were 1 to 2 days later,but for the second generation after redissolution,it is the same.There was no significant difference in different conserving time of 1,3,6,9 months.The influence of liquid nitrogen cryopreservation to survive capability and worm form of Babesia microti is a little,so liquid nitrogen cryopreservation can be a better way to conserving Babesia microti.

Serological and Molecular Detection of Toxoplasma gondii and Babesia microti in the Blood of Rescued Wild Animals in Gangwon-do (Province), Korea

Infections of Toxoplasma gondii and Babesia microti are reported in many wild animals worldwide, but information on their incidence and molecular detection in Korean wild fields is limited. In this study, the prevalence of T. gondii and B. microti infection in blood samples of 5 animal species (37 Chinese water deer, 23 raccoon dogs, 6 roe deer, 1 wild boar, and 3 Eurasian badgers) was examined during 2008–2009 in Gangwon-do (Province), the Republic of Korea (=Korea) by using serological and molecular tests. The overall seropositivity of T. gondii was 8.6% (6/70); 10.8% in Chinese water deer, 4.3% in raccoon dogs, and 16.7% in roe deer. PCR revealed only 1 case of T. gondii infection in Chinese water deer, and phylogenic analysis showed that the positive isolate was practically identical to the highly pathogenetic strain type I. In B. microti PCR, the positive rate was 5.7% (4/70), including 2 Chinese water deer and 2 Eurasian badgers. Phylogenetic analysis results of 18S rRNA and the β-tubulin gene showed that all positive isolates were US-type B. microti. To our knowledge, this is the first report of B. microti detected in Chinese water deer and Eurasian badger from Korea. These results indicate a potentially high prevalence of T. gondii and B. microti in wild animals of Gangwon-do, Korea. Furthermore, Chinese water deer might act as a reservoir for parasite infections of domestic animals.

Immune identification and mass spectrometric analysis of the soluble antigens from Babesia microti / 中华地方病学杂志

Objective To analyze the fractional proteins and immunoreactivity of the soluble antigens from Babesia microti (B.microti),and find the candidate antigens for diagnosis with high sensitivity and specificity.Methods BALB/c mice were inoculated with B.microti-infected red blood cells by intraperitoneal injection.The B.microti were collected from the infected red blood cells when the infection rate reached its peak (infection rate ＞70％),then the soluble antigens were extracted by repeated freezing-thawing and ultrasonic method.The mice sera before and after the infection with B.microti for 7,14,21,28,35,42,49 and 56 days were also collected.The polyacrylamide gel electrophoresis (SDS-PAGE) was used to analyze protein components of the soluble antigens of B.microti and the Western blot was used to analyze the immunoreactivity of the soluble antigens with the pooled mice sera before and after the infection.The specific positive protein bands were identified by Liquid chromatography electrospray ionisation tandem mass spectrometry (LC-ESI-MS/MS),and the amino acid sequences of the proteins were analyzed by bioinformatics tools.Results The results from SDS-PAGE analysis indicated that the soluble antigens of B.microti showed distinct protein bands with the range between 12 and 185 × 103 (kDa,relative molecular mass,Mr),among which 9 main bands and 12 minor bands were obtained.In the Western blot analysis,the protein bands with Mr at 40 and 45 kDa could be recognized by pooled mice sera 7 days after infection;the protein bands with Mr at 40,45,54 and 95 kDa could be recognized by pooled mice sera 14 days after infection;the protein bands with Mr at 27,40,45,54,95 and 110 kDa could be recognized by pooled mice sera 21 days after infection.While,the protein bands with Mr at 27,40,45,54,95,1 10 kDa and other weak-reactive bands were recognized by pooled mice sera 28-56 days after infection,and the reaction became stronger with the infection continued.There were 336 proteins,including surface antigen,heat shock protein 70,seroreactive antigen,Eta subunit of chaperonin containing t-complex polypeptide 1 and unnamed protein products,were identified as the components of soluble antigens after mass spectrometry and sequence analysis.Conclusion The 40,45 and 54 kDa protein components from the soluble antigens of B.microti may be ideal candidate antigens for diagnosis,andtheir potential applications in diagnosing of human babesiosis deserve further study.

Molecular Detection and Seroprevalence of Babesia microti among Stock Farmers in Khutul City, Selenge Province, Mongolia

Babesiosis is an emerging tick-borne disease in humans worldwide; however, little is known about the frequency of infection or prevalence of this disease in other parts of the world, excluding North America. In this study, we aimed to investigate Babesia microti infection frequency in a human population in Mongolia. One hundred blood samples were collected from stock farmers living in Khutul city of Selenge province, Mongolia. The sera and DNA from blood samples were evaluated for the presence of B. microti infection by using indirect fluorescent antibody (IFA) tests and PCR. The positive detection rates obtained using the IFA tests and PCR assays were 7% and 3%, respectively. This study is the first to detect of B. microti infections based on antibody seroprevalence or PCR assays for the presence of B. microti DNA in a Mongolian population.

Babesiosis Humana / Human Babesiosis

La babesiosis es una enfermedad zoonótica poco común, que en la mayoría de los casos es asintomática pero que en personas con alguna inmunodeficiencia puede llegar a ser fatal. La provocan diferentes tipos de babesia, las más frecuentes B. microti en Estados Unidos y B. divergens en Europa y es transmitida por la picadura de la garrapata de ciervo infectada, la lxodes scapularis. El mayor número de casos de la enfermedad se presenta principalmente en verano y primavera, en zonas de la costa noreste de Estados Unidos, Massachussets, especialmente en Nanmcket Island y en Long Island, Nueva York. También hay informes de casos observados en Wisconsin, California, Georgia, Missouri y algunos países europeos. La enfermedad puede causar fiebre, escalofrío, malestar general, fatiga, anemia hemolítica y puede durar desde días hasta meses. El diagnóstico se realiza por examen directo donde se observa al protozoario dentro de los glóbulos rojos. También hay pruebas de inmunofluorescencia y amplificación de ácidos nucleicos por reacción en cadena de la polimerasa PCR. El tratamiento que se ha venido utilizando es Quinina y Clindamicina, aunque tienen muchos efectos secundarios. Se han utilizado también otros medicamentos como azitromicina, tetraciclinas y atovaquona. La principal medida de prevención tiene que ver con el control del vector transmisor de la enfermedad.

A Case of Human Babesiosis Confirmed by Polymerase Chain Reaction and Treated with Atovaquone and Azithromycin

Human babesiosis is a tick-borne infectious disease caused by Babesia species. The clinical diagnosis is difficult because of nonspecific symptoms like flu. Rapid diagnosis of human babesiosis is microscopic examination in peripheral blood smear (Giemsa-stain) which reveals characteristic forms of an intracellular quadruplet parasite. But differentiation between Babesia microti and Plasmodium species can be quite difficult because of the morphologic similarity. We experienced a case of human babesiosis. The patient was a 62-year old Korean male who had been in New Jersey, U.S.A for 2 months. We initially diagnosed as malaria infection because the peripheral blood smear revealed intracellular single ring form organism. But the patient was not improved significantly by the treatment with chloroquine regimen. Finally we confirmed human babesiosis by polymerase chain reaction for Babesia microti. We treated the patient successfully with a regimen of atovaquone and azithromycin which has fewer adverse reactions than a regimen of clindamycin and quinine.

A Case of Human Babesiosis Confirmed by Polymerase Chain Reaction and Treated with Atovaquone and Azithromycin

Human babesiosis is a tick-borne infectious disease caused by Babesia species. The clinical diagnosis is difficult because of nonspecific symptoms like flu. Rapid diagnosis of human babesiosis is microscopic examination in peripheral blood smear (Giemsa-stain) which reveals characteristic forms of an intracellular quadruplet parasite. But differentiation between Babesia microti and Plasmodium species can be quite difficult because of the morphologic similarity. We experienced a case of human babesiosis. The patient was a 62-year old Korean male who had been in New Jersey, U.S.A for 2 months. We initially diagnosed as malaria infection because the peripheral blood smear revealed intracellular single ring form organism. But the patient was not improved significantly by the treatment with chloroquine regimen. Finally we confirmed human babesiosis by polymerase chain reaction for Babesia microti. We treated the patient successfully with a regimen of atovaquone and azithromycin which has fewer adverse reactions than a regimen of clindamycin and quinine.