Apicomplexan parasites predominantly generate ATP and lactic acid through glycolysis and anaerobic glucose metabolism,incorporating CO_(2) into glycolysis via a stage-dependent phosphoenolpyruvate carboxylase(PEPC)mec...Apicomplexan parasites predominantly generate ATP and lactic acid through glycolysis and anaerobic glucose metabolism,incorporating CO_(2) into glycolysis via a stage-dependent phosphoenolpyruvate carboxylase(PEPC)mechanism.Although the role of PEPC in plant and bacterial carbon fixation is well documented,its function within Babesia remains largely unexplored.This study employs reverse genetics to probe the biological role of PEPC in Babesia gibsoni,noting its conservation across similar protozoa,suggesting a pivotal and conserved biological function.Western blotting and immunofluorescence(IFA)experiments using the BgPEPC-3×Flag strain revealed that the BgPEPC protein has a molecular weight of 105 kDa and localizes predominantly to the cytoplasm.Attempts to knock out the PEPC gene in BgPEPC-3×Flag strains failed under standard media conditions,succeeded only with the addition of 5 mM malate,an upstream metabolite of oxaloacetic acid(OAA).In addition to malate,the downstream metabolite of OAA can also partially compensate for the phenotypic defects caused by PEPC deficiency.This intervention alleviated severe growth deficits,underscoring the critical role of aspartate in the parasite lifecycle.Moreover,metabolic inhibitors such as L-cycloserine and triazamidine,which target aspartate aminotransferase and mitochondrial functions,respectively,demonstrated increased efficacy against BgPEPC knockout strains.The lack of a compensatory response to malic acid supplementation underscores the integral role of BgPEPC in intermediary carbon metabolism and its necessity in providing aspartate as a precursor to pyrimidine synthesis.Collectively,these findings suggest that PEPC could be a potential target for future drug development against B.gibsoni infections.展开更多
Objective:To evaluate the antipiroplasmic activities of methanolic extract of Olea europaea(MOE)and acetonic extract of Acacia laeta(AAL)against Babesia and Theileria parasites in vitro and evaluate the chemotherapeut...Objective:To evaluate the antipiroplasmic activities of methanolic extract of Olea europaea(MOE)and acetonic extract of Acacia laeta(AAL)against Babesia and Theileria parasites in vitro and evaluate the chemotherapeutic effects of these extracts against Babesia(B.)microti in vivo.Methods:Fluorescence assay using SYBR Green 1 nucleic acid stain was used to detect inhibitory effects of the two extracts as well as the combination effects of the two extracts with diminazene aceturate and atovaquone on four Babesia species and Theileria equi in vitro while for in vivo experiments,8-weekold female BALB/c mice were injected intraperitoneally with 1× 107 B.microti-iRBCs and treated orally at a dose of 150 mg/kg of both extracts.Results:The half maximal inhibitory concentration(IC50)values of AAL against B.bovis,B.bigemina,B.divergens,B.caballi,and Theileria equi were lower than those of MOE extracts.Toxicity assay on Madin-Darby bovine kidney,mouse embryonic fibroblast(NIH/3T3),and human foreskin fibroblast cell lines showed that MOE and AAL affected only the viability of Madin-Darby bovine kidney cell line with half maximal effective concentrations(EC50)of(794.7±41.9)and(873.9±17.5)μg/mL,respectively.The oral treatments of MOE and AAL at 150 mg/kg inhibited the growth of B.microti in mice by 80.4% and 64.4%,respectively.The MOE and diminazene aceturate combination showed a higher chemotherapeutic effect than that of monotherapy.Conclusions:MOE and AAL have the potential to be an alternative remedy for treating piroplasmosis.Furthermore,the combination therapy of MOE + DA was more potent against B.microti infection in mice than their monotherapies.展开更多
This work aimed to find quantitative phenotypic traits that can be used to discriminate the levels of resistance/susceptibility to B. bovis and B. bigemina in two groups of cattle presenting the highest (H) or lowest ...This work aimed to find quantitative phenotypic traits that can be used to discriminate the levels of resistance/susceptibility to B. bovis and B. bigemina in two groups of cattle presenting the highest (H) or lowest (L) infection levels and Rhipicephalus microplus ticks count. The animals were selected from a previous study of 50 Canchim (5/8 Charolais/zebu) heifers raised in an endemic area for these parasites. These animals were evaluated regarding their TNFα, IL10, IFN-γ, IL12 and iNOS mRNA levels. No differences were found between these groups regarding TNFα, IFN-γ, IL12β or iNOS transcripts. However, the IL10 transcripts were significantly higher in the H group compared to the L group. Moreover, significant correlation coefficients were observed between B. bovis loads and both IL10 and IFN-γ transcripts, while no correlations were found for B. bigemina loads and all tested immune-related transcripts, suggesting that differential IL10 mRNA profiles were closely associated to B. bovis loads. Our results have contributed to a better understanding of the immune responses against Babesia infection, as we demonstrated that the IL10 cytokine levels might also influence or be influenced by parasitemia levels in persistently infected animals.展开更多
Objective:To determine the presence of Babesia bovis(B.bovis) in large ruminants in southern Punjab and its effect on hematological and serum biochemical profile of host animals.Methods:Blood samples were collected fr...Objective:To determine the presence of Babesia bovis(B.bovis) in large ruminants in southern Punjab and its effect on hematological and serum biochemical profile of host animals.Methods:Blood samples were collected from 144 large ruminants,including 105 cattle and 39 buffaloes,from six districts in southern Punjab including Multan,Layyah,Muzaffar Garh,Bhakar,Bahawalnagar and Vehari.Data on the characteristics of animals and herds were collected through questionnaires.Different blood(hemoglobin,glucose) and serum(ALT,AST,LDH,cholesterol)parameters of calves and cattle were measured and compared between parasite positive and negative samples to demonstrate the effect of B.bovis on the blood and serological profile of infected animals.Results:27 out of 144 animals.from 5 out of 6 sampling districts,produced the541-bp fragment specific for B.bovis.Age of animals(P=0.02).presence of ticks on animals(P=0.04)and presence of ticks on dogs associated with herds(P=0.5) were among the major risk factors involved in the spread of bovine babesiosis in the study area.ALT concentrations were the only serum biochemical values that significantly varied between parasite positive and negative cattle.Conclusions:This study has reported for the first time the presence of B.bovis in large ruminant and the results can lead to the prevention of babesiosis in the region to increase the livestock output.展开更多
GAVAC (Heber Biotec S.A, Havana, Cuba) is a commercially available vaccine developed with the Rhipicephalus (Boophilus) microplus Bm86 recombinant antigen. Bm86 is a “concealed” antigen that is present in the plasma...GAVAC (Heber Biotec S.A, Havana, Cuba) is a commercially available vaccine developed with the Rhipicephalus (Boophilus) microplus Bm86 recombinant antigen. Bm86 is a “concealed” antigen that is present in the plasmatic membrane of tick gut epithelial cells with unknown function so far. It is well known that after vaccination in the last fifteen years in Cuba, there was a significant decrease of babesiosis (Babesia bovis and Babesia bigemina) and anaplasmosis (Anaplasma marginale) in cattle. A reduced transmission capacity of ticks fed on tick-immune animals and humans has been reported for several tick-borne pathogens. Recent experiments have demonstrated that an anti-tick vaccine may contribute to the control of tick-borne pathogens not only by decreasing the exposure of susceptible hosts to ticks, but also by reducing the vector capacity of ticks. In this study, the potential of Bm86 vaccination to interfere with pathogen transmission among ticks was evaluated by using as experimental model the brown dog tick Rhipicephalus sanguineus and the tickborne Babesia canis and Ehrlichia canis pathogens. Dogs, vaccinated and not vaccinated, were infested with pathogen-infected ticks and noninfected nymphs of R. sanguineus. After feeding, the pathogen transmission to newly molted adults from co-feeding uninfected nymphs was studied by conventional PCR and qPCR. Results suggest that the anti-Bm86 antibodies could be able to block the transmission of B. canis and/or E. canis from infected to non-infected ticks.展开更多
Objective:To evaluate the combination therapy of pyronaridine tetraphosphate and diminazene aceturate against Babesia in vitro and in vivo.Methods:Bioinformatic analysis was performed using atom pair fingerprints.An i...Objective:To evaluate the combination therapy of pyronaridine tetraphosphate and diminazene aceturate against Babesia in vitro and in vivo.Methods:Bioinformatic analysis was performed using atom pair fingerprints.An in vitro combination test was performed against Babesia bovis and Theileria equi.Moreover,the in vivo chemotherapeutic efficacy of pyronaridine tetraphosphate in combination with diminazene aceturate was investigated against the growth of Babesia microti in mice using a fluorescence inhibitory assay.Results:Pyronaridine tetraphosphate and diminazene aceturate exhibited nearly similar molecular weights.The in vitro combination of pyronaridine tetraphosphate and diminazene aceturate was synergistic on Babesia bovis and additive on Theileria equi.In addition,5 mg/kg pyronaridine tetraphosphate combined with 10 mg/kg diminazene aceturate inhibited Babesia microti growth significantly compared with those observed after treatment with 25 mg/kg diminazene aceturate alone from day 6 post treatment to day 12 post treatment.The combination therapy also normalized the hematological parameters of infected mice.Conclusions:An oral dose of pyronaridine tetraphosphate combined with a subcutaneous dose of diminazene aceturate inhibits Babesia in vitro and in mice,suggesting it might be a new paradigm for the treatment of babesiosis.展开更多
Background Babesiosis is a zoonotic disease caused by the intraerythrocytic parasite Babesia,which poses a serious threat to public health.Currently,the prevalence of babesiosis in domestic animals and the genetic div...Background Babesiosis is a zoonotic disease caused by the intraerythrocytic parasite Babesia,which poses a serious threat to public health.Currently,the prevalence of babesiosis in domestic animals and the genetic diversity of Babesia in Central China have not been comprehensively studied.Methods In this study,we collected 1093 ticks,including 95.24%(1041/1093)Haemaphysalis longicornis,4.67%(51/1093)Rhipicephalus microplus,and 0.09%(1/1093)Ixodes sinensis.Blood samples from 216 goats,56 cattle,and 25 dogs were collected from Suizhou City,Hubei Province,China,and animal blood DNA was extracted for the detection of Babesia with PCR.Results PCR results showed that 50.00%(28/56)of cattle and 32.00%(8/25)of dogs were Babesia-positive,including for Babesia bovis 3.57%(2/56),B.bigemina 3.57%(2/56),and B.ovata 42.86%(24/56)in cattle and B.gibsoni 32.00%(8/25)in dogs.All goats(216)and ticks(1093)were Babesia-negative.Conclusions Our findings showed that Babesia infections are prevalent in cattle and dogs in Central China,indicating that babesiosis should be monitored in animals and humans in Central China.展开更多
A systems biology approach was employed to gain insight into tick biology and interactions between vectors and pathogens.Haemaphysalis longicornis serves as one of the primary vectors of Babesia microti,significantly ...A systems biology approach was employed to gain insight into tick biology and interactions between vectors and pathogens.Haemaphysalis longicornis serves as one of the primary vectors of Babesia microti,significantly impacting human and animal health.Obtaining more information about their relationship is crucial for a comprehensive un-derstanding of tick and pathogen biology,pathogen transmission dynamics,and potential control strategies.RNA sequencing of uninfected and B.microti-infected ticks resulted in the identification of 15056 unigenes.Among these,1051 were found to be differentially expressed,with 796 being upregulated and 255 downregulated(P<0.05).Integrated tran-scriptomics datasets revealed the pivotal role of immune-related pathways,including the Toll,Janus kinase/signal transducer and activator of transcription(JAK-STAT),immunod-eficiency,and RNA interference(RNAi)pathways,in response to infection.Consequently,3 genes encoding critical transcriptional factor Dorsal,Relish,and STAT were selected for RNAi experiments.The knockdown of Dorsal,Relish,and STAT resulted in a substantial increase in Babesia infection levels compared to the respective controls.These findings significantly advanced our understanding of tick–Babesia molecular interactions and pro-posed novel tick antigens as potential vaccine targets against tick infestations and pathogen transmission.展开更多
Background Human babesiosis,caused by intraerythrocytic protozoa of the genus Babesia(Piroplasmida,Babesiidae),is a globally emerging zoonosis transmitted primarily through Ixodes spp.ticks.Babesia microti,which is en...Background Human babesiosis,caused by intraerythrocytic protozoa of the genus Babesia(Piroplasmida,Babesiidae),is a globally emerging zoonosis transmitted primarily through Ixodes spp.ticks.Babesia microti,which is endemic particularly in the northeastern and midwestern United States,accounts for the majority of globally reported human cases.Recent studies highlight its spread to non-traditional regions and cross-border transmission,driven by climate change,blood transfusions and increased human mobility.Despite increasing reports of autochthonous B.microti infections in certain areas of China,imported cases remain critically underrecognized due to overlapping clinical manifestations with malaria and limited diagnostic awareness.Case presentation We report a diagnostically challenging case of acute B.microti infection in a 52-year-old Chinese woman,presenting with a sudden recurrent fever(39.0–41.0℃),hemolytic anemia(hemoglobin 104 g/L),thrombocytopenia(platelet 78×10^(9)/L)and splenic hypodense lesions on July 11,2023,seven days after returning from a 14-day visit to rural Wisconsin,United States.Peripheral blood smears demonstrated characteristic intraerythrocytic ring forms(parasitemia:7800 organisms/μl)and pathognomonic"Maltese cross"tetrads.Polymerase chain reaction(PCR)targeting the 18S rRNA gene confirmed B.microti infection(GenBank No.PP087232),showing 99.8%identity with the US-type strain Gray(AY693840)and the sequence obtained from a US travel-acquired case in Singapore(MK609547).The patient received intravenous clindamycin(600 mg twice daily),oral dihydroartemisinin(80 mg twice daily),packed red blood cell transfusions,and supportive care,ultimately achieving full recovery after 17 days.Conclusions This study documented the first imported cases of human babesiosis in China,emphasizing the need for heightened clinical and public health vigilance.Screening travelers from endemic areas presenting with fever or hemolytic anemia for Babesia,bolstering molecular diagnosis,improving transfusion safety,and intensifying regional surveillance are crucial in reducing underdiagnosis and preventing transmission.These measures are essential for controlling babesiosis in China.展开更多
Background:Babesiosis is an emerging health risk in several parts of the world.However,little is known about the prevalence of Babesia in malaria-endemic countries.The area along the China-Myanmar border in Yunnan is ...Background:Babesiosis is an emerging health risk in several parts of the world.However,little is known about the prevalence of Babesia in malaria-endemic countries.The area along the China-Myanmar border in Yunnan is a main endemic area of malaria in P.R.China,however,human infection with Babesia microti(B.microti)is not recognized in this region,and its profile of co-infection is not yet clear.Methods:To understand its profile of co-infections with B.microti,our investigation was undertaken in the malaria-endemic area along the China-Myanmar border in Yunnan between April 2012 and June 2013.Four parasite species,including B.microti,Plasmodium falciparum(P.falciparum),P.vivax,and P.malariae,were identified among 449 suspected febrile persons detected by nested polymerase chain reaction(PCR)assay based on small subunit ribosomal ribonucleic acid(RNA)genes of B.microti and Plasmodium spp.Results:Of all the collected samples from febrile patients,mono-infection with B.microti,P.vivax,P.falciparum,and P.malariae accounted for 1.8%(8/449),9.8%(44/449),2.9%(13/449),and 0.2%(1/449),respectively.The rate of mixed infections of B.microti with P.falciparum or P.vivax are both 0.2%(1/449),and mixed infections of P.falciparum and P.vivax accounted for 1.1%(5/449).Conclusions:This report supports the hypothesis that babesiosis caused by B.microti is emerging along the China-Myanmar border in the Yunnan province,P.R.China,but it was ignored because of low parasitemia or mixed infection with Plasmodium spp.More sensitive and specific diagnosis methods are needed to find the rapid response mechanism of emergency for babesiosis and malaria co-prevalence areas.展开更多
Background:Babesiosis is an uncommon but emerging tick-borne disease caused by the genus Babesia.In this case study,we report a case of human infection with a novel Babesia sp.in China.Findings:The patient in question...Background:Babesiosis is an uncommon but emerging tick-borne disease caused by the genus Babesia.In this case study,we report a case of human infection with a novel Babesia sp.in China.Findings:The patient in question had been suffering from repetitive occurrences of mild fever of unknown origin and fatigue for 10 years.Ring forms,tetrads,and one or two dots of chromatin or trophozoite-like organisms were observed in the patient’s thin blood smears and bone marrow smears.Using a confocal laser-scanning microscope,it was observed that the patient’s serum had reactivity with the surface proteins of the B.microti strain.Electron microscopy revealed oval red blood cells with 1~2μm of knob protrusions in the cellular membrane.The results of the Babesia-specific nested PCR assay for 18S rRNA confirmed the presence of Babesia infection.The construction of a phylogenetic relationship showed clustering with B.microti and B.duncani,which was identified as a novel Babesia species and named as Babesia sp.XXB/HangZhou.Azithromycin,doxycycline,and moxifloxacin hydrochloride were shown to relieve symptoms but were not as effective after continuous usage.After atovaquone(Mepron®)administration,the patient recovered from fever and tested negative for detection of Babesia-specific genes.Conclusion:Babesia sp.XXB/HangZhou is a novel Babesia species,which causes mild babesiosis in an immunocompetent patient.展开更多
Background: Babesiosis is an emerging tick-borne zoonotic infectious disease.Babesia microti is responsible for most cases of human babesiosis globally.It is important to investigate the prevalence of B.microti in the...Background: Babesiosis is an emerging tick-borne zoonotic infectious disease.Babesia microti is responsible for most cases of human babesiosis globally.It is important to investigate the prevalence of B.microti in the mammalian host population of a specific region in order to elucidate mechanisms of pathogen transmission and to define geographic areas where humans face the greatest risk of exposure.The aim of this study is to understand the prevalence and genotypes of B.microti in the small mammals that are found in Beijing,China.Methods:: We trapped small mammals from all of the 16 urban,suburban,and outer suburban districts of Beijing during the years 2014,2017 and 2018.Genomic DNA was extracted from the heart tissues individually and the Babesia 18S rRNA gene was detected by PCR.The genotypes of B.microti were identified based on sequence alignments and phylogenetic analysis.The morphology of the parasites was observed under light microscopy.The risk factors were analyzed statistically based on both univariate analyses and multivariate logistic regression.Results: A total of 1391 small mammals were collected.Positive infection of B.microti was detected in 12.1%(168/1391)of small mammals from 15 out of the 16 districts.Both Kobe-type and U.S.-type B.microti,accounting for 9.5%and 2.7%,respectively,were identified.Classic diverse morphologic forms of B.microti were observed.Specific types of ecological habitats including shrub areas,broad-leaved forest,and cropland were revealed to be risk factors associated with B.microti infection.Conclusions: This study demonstrated the wide prevalence of B.microti infection in eight species of small mammals in Beijing,with Kobe-type more prevalent than U.S.-type.This study provides fundamental information for the development of informed prevention and control measures by public health authorities;the data gathered indicates a need for further monitoring of both clinical diseases in individuals presenting with babesiosis-like symptoms,as well as the infection status of ticks in high risk areas.展开更多
The emerging Babesia venatorum upsurges as a potential health threat occurring in China and other endemic countries.Few attempts to isolate and culture the Babesia species had been conducted in vitro.We collected the ...The emerging Babesia venatorum upsurges as a potential health threat occurring in China and other endemic countries.Few attempts to isolate and culture the Babesia species had been conducted in vitro.We collected the questing Ixodes persulcatus from identified endemic areas and allowed them to feed on the severe combined immunodeficiency(SCID)mice.The positive mice were chosen to provide positive erythrocytes with asexual B.venatorum for continuous culture in mouse or human erythrocytes in vitro,with RPMI 1640 medium and appropriate serum.With B.venatorum in the SCID mice,erythrocytes were cultured in vitro for confirmation by morphological observations with transmission electron microscopes.Sequences of B.venatorum were then identified by way of conventional PCR amplification.Parasitemia counts monitored the growth of B.venatorum on thin blood smears and real-time quantitative PCR in parallel.As expected,B.venatorum positive mice were harvested by sufficient attacks of I.persulcatus ticks.The erythrocytes of the infected mice were then inoculated and successfully cultured in donated erythrocytes from humans and mice in RPMI 1640 culture medium.Active growth of B.venatorum was well demonstrated in human erythrocytes with 3.3 times parasite-load when compared with a mouse under similar conditions.With the increased subcultures,a prolonged period of detectable parasitemia with much higher peak parasitemia and shorter time to reach peak parasitemia were observed in the following subcultures.A new strategy for isolation and in vitro culture of B.venatorum has been provided with a continuous supply of sufficient pathogens to satisfy human babesiosis's testings and clinical therapies.展开更多
【目的】探究牛巴贝斯虫(Babesia bovis)SBP2蛋白(spherical body protein 2,SBP2)的生物信息学特征并进行原核表达及多克隆抗体制备,为牛巴贝斯虫疫苗和诊断抗原筛选提供理论依据。【方法】对牛巴贝斯虫SBP2基因进行扩增和克隆,运用Meg...【目的】探究牛巴贝斯虫(Babesia bovis)SBP2蛋白(spherical body protein 2,SBP2)的生物信息学特征并进行原核表达及多克隆抗体制备,为牛巴贝斯虫疫苗和诊断抗原筛选提供理论依据。【方法】对牛巴贝斯虫SBP2基因进行扩增和克隆,运用Mega7.0构建牛巴贝斯虫SBP2蛋白系统进化树,利用IEDB Analysis Resource等生物信息学方法对牛巴贝斯虫SBP2蛋白的磷酸化位点和B细胞抗原表位进行预测分析;对SBP2蛋白与弓形虫致密颗粒蛋白(GRA)的氨基酸序列比对分析;构建原核表达载体p ET-28a-SBP2,诱导表达SBP2重组蛋白并进行蛋白纯化,通过Western blotting验证SBP2重组蛋白反应原性;以SBP2重组蛋白为免疫原,免疫BALB/c小鼠制备多克隆抗体,并利用间接ELISA方法检测其效价。【结果】系统进化树显示,本研究牛巴贝斯虫SBP2蛋白与泰国株(OM46855)的氨基酸序列亲缘关系最近。生物信息学分析显示,SBP2蛋白包含17个B细胞抗原表位和31个磷酸化位点,其中包括12个丝氨酸位点、14个苏氨酸位点及5个酪氨酸位点。牛巴贝斯虫SBP2蛋白氨基酸序列与弓形虫GRA蛋白之间有很强的相关性。成功构建了重组质粒p ET-28a-SBP2;Western blotting结果显示,SBP2重组蛋白分子质量大小约为35ku,具有良好的反应原性;制备的多克隆抗体效价为1∶204800。【结论】本研究通过预测牛巴贝斯虫SBP2蛋白生物学特性,加深了对SBP2蛋白的认识,利用原核表达系统成功获得牛巴贝斯虫SBP2重组蛋白,并获得其小鼠源多克隆抗体,为进一步研究SBP2功能及其在牛巴贝斯虫致病机制中的作用奠定了基础。展开更多
基金supported by the National Natural Science Foundation of China(32172879)the National Key Research and Development Program of China(2022YFD1801700 and 2022YFD1800200)the Top-notch Young Talent Supporting Program to Lan He.Additionally,funding was obtained from the Fundamental Research Funds for the Central Universities(2662020DKPY016 and 2262022DKYJ001).
文摘Apicomplexan parasites predominantly generate ATP and lactic acid through glycolysis and anaerobic glucose metabolism,incorporating CO_(2) into glycolysis via a stage-dependent phosphoenolpyruvate carboxylase(PEPC)mechanism.Although the role of PEPC in plant and bacterial carbon fixation is well documented,its function within Babesia remains largely unexplored.This study employs reverse genetics to probe the biological role of PEPC in Babesia gibsoni,noting its conservation across similar protozoa,suggesting a pivotal and conserved biological function.Western blotting and immunofluorescence(IFA)experiments using the BgPEPC-3×Flag strain revealed that the BgPEPC protein has a molecular weight of 105 kDa and localizes predominantly to the cytoplasm.Attempts to knock out the PEPC gene in BgPEPC-3×Flag strains failed under standard media conditions,succeeded only with the addition of 5 mM malate,an upstream metabolite of oxaloacetic acid(OAA).In addition to malate,the downstream metabolite of OAA can also partially compensate for the phenotypic defects caused by PEPC deficiency.This intervention alleviated severe growth deficits,underscoring the critical role of aspartate in the parasite lifecycle.Moreover,metabolic inhibitors such as L-cycloserine and triazamidine,which target aspartate aminotransferase and mitochondrial functions,respectively,demonstrated increased efficacy against BgPEPC knockout strains.The lack of a compensatory response to malic acid supplementation underscores the integral role of BgPEPC in intermediary carbon metabolism and its necessity in providing aspartate as a precursor to pyrimidine synthesis.Collectively,these findings suggest that PEPC could be a potential target for future drug development against B.gibsoni infections.
基金supported by the Japan Society for the Promotion of Science(JSPS)(KAKEN Grant Number:18H02337)
文摘Objective:To evaluate the antipiroplasmic activities of methanolic extract of Olea europaea(MOE)and acetonic extract of Acacia laeta(AAL)against Babesia and Theileria parasites in vitro and evaluate the chemotherapeutic effects of these extracts against Babesia(B.)microti in vivo.Methods:Fluorescence assay using SYBR Green 1 nucleic acid stain was used to detect inhibitory effects of the two extracts as well as the combination effects of the two extracts with diminazene aceturate and atovaquone on four Babesia species and Theileria equi in vitro while for in vivo experiments,8-weekold female BALB/c mice were injected intraperitoneally with 1× 107 B.microti-iRBCs and treated orally at a dose of 150 mg/kg of both extracts.Results:The half maximal inhibitory concentration(IC50)values of AAL against B.bovis,B.bigemina,B.divergens,B.caballi,and Theileria equi were lower than those of MOE extracts.Toxicity assay on Madin-Darby bovine kidney,mouse embryonic fibroblast(NIH/3T3),and human foreskin fibroblast cell lines showed that MOE and AAL affected only the viability of Madin-Darby bovine kidney cell line with half maximal effective concentrations(EC50)of(794.7±41.9)and(873.9±17.5)μg/mL,respectively.The oral treatments of MOE and AAL at 150 mg/kg inhibited the growth of B.microti in mice by 80.4% and 64.4%,respectively.The MOE and diminazene aceturate combination showed a higher chemotherapeutic effect than that of monotherapy.Conclusions:MOE and AAL have the potential to be an alternative remedy for treating piroplasmosis.Furthermore,the combination therapy of MOE + DA was more potent against B.microti infection in mice than their monotherapies.
文摘This work aimed to find quantitative phenotypic traits that can be used to discriminate the levels of resistance/susceptibility to B. bovis and B. bigemina in two groups of cattle presenting the highest (H) or lowest (L) infection levels and Rhipicephalus microplus ticks count. The animals were selected from a previous study of 50 Canchim (5/8 Charolais/zebu) heifers raised in an endemic area for these parasites. These animals were evaluated regarding their TNFα, IL10, IFN-γ, IL12 and iNOS mRNA levels. No differences were found between these groups regarding TNFα, IFN-γ, IL12β or iNOS transcripts. However, the IL10 transcripts were significantly higher in the H group compared to the L group. Moreover, significant correlation coefficients were observed between B. bovis loads and both IL10 and IFN-γ transcripts, while no correlations were found for B. bigemina loads and all tested immune-related transcripts, suggesting that differential IL10 mRNA profiles were closely associated to B. bovis loads. Our results have contributed to a better understanding of the immune responses against Babesia infection, as we demonstrated that the IL10 cytokine levels might also influence or be influenced by parasitemia levels in persistently infected animals.
基金supported by the Direetorate of Research and External Linkages,Bahauddin Zakariya University.Multan.Pakistan(grant No.DR&EI/D-40 dated 05-04-2010)
文摘Objective:To determine the presence of Babesia bovis(B.bovis) in large ruminants in southern Punjab and its effect on hematological and serum biochemical profile of host animals.Methods:Blood samples were collected from 144 large ruminants,including 105 cattle and 39 buffaloes,from six districts in southern Punjab including Multan,Layyah,Muzaffar Garh,Bhakar,Bahawalnagar and Vehari.Data on the characteristics of animals and herds were collected through questionnaires.Different blood(hemoglobin,glucose) and serum(ALT,AST,LDH,cholesterol)parameters of calves and cattle were measured and compared between parasite positive and negative samples to demonstrate the effect of B.bovis on the blood and serological profile of infected animals.Results:27 out of 144 animals.from 5 out of 6 sampling districts,produced the541-bp fragment specific for B.bovis.Age of animals(P=0.02).presence of ticks on animals(P=0.04)and presence of ticks on dogs associated with herds(P=0.5) were among the major risk factors involved in the spread of bovine babesiosis in the study area.ALT concentrations were the only serum biochemical values that significantly varied between parasite positive and negative cattle.Conclusions:This study has reported for the first time the presence of B.bovis in large ruminant and the results can lead to the prevention of babesiosis in the region to increase the livestock output.
文摘GAVAC (Heber Biotec S.A, Havana, Cuba) is a commercially available vaccine developed with the Rhipicephalus (Boophilus) microplus Bm86 recombinant antigen. Bm86 is a “concealed” antigen that is present in the plasmatic membrane of tick gut epithelial cells with unknown function so far. It is well known that after vaccination in the last fifteen years in Cuba, there was a significant decrease of babesiosis (Babesia bovis and Babesia bigemina) and anaplasmosis (Anaplasma marginale) in cattle. A reduced transmission capacity of ticks fed on tick-immune animals and humans has been reported for several tick-borne pathogens. Recent experiments have demonstrated that an anti-tick vaccine may contribute to the control of tick-borne pathogens not only by decreasing the exposure of susceptible hosts to ticks, but also by reducing the vector capacity of ticks. In this study, the potential of Bm86 vaccination to interfere with pathogen transmission among ticks was evaluated by using as experimental model the brown dog tick Rhipicephalus sanguineus and the tickborne Babesia canis and Ehrlichia canis pathogens. Dogs, vaccinated and not vaccinated, were infested with pathogen-infected ticks and noninfected nymphs of R. sanguineus. After feeding, the pathogen transmission to newly molted adults from co-feeding uninfected nymphs was studied by conventional PCR and qPCR. Results suggest that the anti-Bm86 antibodies could be able to block the transmission of B. canis and/or E. canis from infected to non-infected ticks.
基金supported by Deputyship for Research&Innovation,Ministry of Education in Saudi Arabia through the project number:ISP23-73.
文摘Objective:To evaluate the combination therapy of pyronaridine tetraphosphate and diminazene aceturate against Babesia in vitro and in vivo.Methods:Bioinformatic analysis was performed using atom pair fingerprints.An in vitro combination test was performed against Babesia bovis and Theileria equi.Moreover,the in vivo chemotherapeutic efficacy of pyronaridine tetraphosphate in combination with diminazene aceturate was investigated against the growth of Babesia microti in mice using a fluorescence inhibitory assay.Results:Pyronaridine tetraphosphate and diminazene aceturate exhibited nearly similar molecular weights.The in vitro combination of pyronaridine tetraphosphate and diminazene aceturate was synergistic on Babesia bovis and additive on Theileria equi.In addition,5 mg/kg pyronaridine tetraphosphate combined with 10 mg/kg diminazene aceturate inhibited Babesia microti growth significantly compared with those observed after treatment with 25 mg/kg diminazene aceturate alone from day 6 post treatment to day 12 post treatment.The combination therapy also normalized the hematological parameters of infected mice.Conclusions:An oral dose of pyronaridine tetraphosphate combined with a subcutaneous dose of diminazene aceturate inhibits Babesia in vitro and in mice,suggesting it might be a new paradigm for the treatment of babesiosis.
基金supported by the National Natural Science Foundation of China(grant number 32470155)Key R&D Program of Hubei Province,China(2022BCE063).
文摘Background Babesiosis is a zoonotic disease caused by the intraerythrocytic parasite Babesia,which poses a serious threat to public health.Currently,the prevalence of babesiosis in domestic animals and the genetic diversity of Babesia in Central China have not been comprehensively studied.Methods In this study,we collected 1093 ticks,including 95.24%(1041/1093)Haemaphysalis longicornis,4.67%(51/1093)Rhipicephalus microplus,and 0.09%(1/1093)Ixodes sinensis.Blood samples from 216 goats,56 cattle,and 25 dogs were collected from Suizhou City,Hubei Province,China,and animal blood DNA was extracted for the detection of Babesia with PCR.Results PCR results showed that 50.00%(28/56)of cattle and 32.00%(8/25)of dogs were Babesia-positive,including for Babesia bovis 3.57%(2/56),B.bigemina 3.57%(2/56),and B.ovata 42.86%(24/56)in cattle and B.gibsoni 32.00%(8/25)in dogs.All goats(216)and ticks(1093)were Babesia-negative.Conclusions Our findings showed that Babesia infections are prevalent in cattle and dogs in Central China,indicating that babesiosis should be monitored in animals and humans in Central China.
基金supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions,National Natural Science Foundation of China(32170142,81971917,81271792,81471571)Jiangsu Natural Science Foundation(BK20211310),and funding from Suzhou International Joint Laboratory for Diagnosis and Treatment of Brain Diseases.
文摘A systems biology approach was employed to gain insight into tick biology and interactions between vectors and pathogens.Haemaphysalis longicornis serves as one of the primary vectors of Babesia microti,significantly impacting human and animal health.Obtaining more information about their relationship is crucial for a comprehensive un-derstanding of tick and pathogen biology,pathogen transmission dynamics,and potential control strategies.RNA sequencing of uninfected and B.microti-infected ticks resulted in the identification of 15056 unigenes.Among these,1051 were found to be differentially expressed,with 796 being upregulated and 255 downregulated(P<0.05).Integrated tran-scriptomics datasets revealed the pivotal role of immune-related pathways,including the Toll,Janus kinase/signal transducer and activator of transcription(JAK-STAT),immunod-eficiency,and RNA interference(RNAi)pathways,in response to infection.Consequently,3 genes encoding critical transcriptional factor Dorsal,Relish,and STAT were selected for RNAi experiments.The knockdown of Dorsal,Relish,and STAT resulted in a substantial increase in Babesia infection levels compared to the respective controls.These findings significantly advanced our understanding of tick–Babesia molecular interactions and pro-posed novel tick antigens as potential vaccine targets against tick infestations and pathogen transmission.
基金supported by the National Key Research and Development Program of China(2024YFC2607504).
文摘Background Human babesiosis,caused by intraerythrocytic protozoa of the genus Babesia(Piroplasmida,Babesiidae),is a globally emerging zoonosis transmitted primarily through Ixodes spp.ticks.Babesia microti,which is endemic particularly in the northeastern and midwestern United States,accounts for the majority of globally reported human cases.Recent studies highlight its spread to non-traditional regions and cross-border transmission,driven by climate change,blood transfusions and increased human mobility.Despite increasing reports of autochthonous B.microti infections in certain areas of China,imported cases remain critically underrecognized due to overlapping clinical manifestations with malaria and limited diagnostic awareness.Case presentation We report a diagnostically challenging case of acute B.microti infection in a 52-year-old Chinese woman,presenting with a sudden recurrent fever(39.0–41.0℃),hemolytic anemia(hemoglobin 104 g/L),thrombocytopenia(platelet 78×10^(9)/L)and splenic hypodense lesions on July 11,2023,seven days after returning from a 14-day visit to rural Wisconsin,United States.Peripheral blood smears demonstrated characteristic intraerythrocytic ring forms(parasitemia:7800 organisms/μl)and pathognomonic"Maltese cross"tetrads.Polymerase chain reaction(PCR)targeting the 18S rRNA gene confirmed B.microti infection(GenBank No.PP087232),showing 99.8%identity with the US-type strain Gray(AY693840)and the sequence obtained from a US travel-acquired case in Singapore(MK609547).The patient received intravenous clindamycin(600 mg twice daily),oral dihydroartemisinin(80 mg twice daily),packed red blood cell transfusions,and supportive care,ultimately achieving full recovery after 17 days.Conclusions This study documented the first imported cases of human babesiosis in China,emphasizing the need for heightened clinical and public health vigilance.Screening travelers from endemic areas presenting with fever or hemolytic anemia for Babesia,bolstering molecular diagnosis,improving transfusion safety,and intensifying regional surveillance are crucial in reducing underdiagnosis and preventing transmission.These measures are essential for controlling babesiosis in China.
基金The research has been partially supported by the Special Fund for Health Research in the Public Interest China(No.201202019)Strengthen Action Plan for Shanghai Public Health System Construction 2011–2013(GW-11)by the National S&T Major Program(No.2012ZX10004-220).
文摘Background:Babesiosis is an emerging health risk in several parts of the world.However,little is known about the prevalence of Babesia in malaria-endemic countries.The area along the China-Myanmar border in Yunnan is a main endemic area of malaria in P.R.China,however,human infection with Babesia microti(B.microti)is not recognized in this region,and its profile of co-infection is not yet clear.Methods:To understand its profile of co-infections with B.microti,our investigation was undertaken in the malaria-endemic area along the China-Myanmar border in Yunnan between April 2012 and June 2013.Four parasite species,including B.microti,Plasmodium falciparum(P.falciparum),P.vivax,and P.malariae,were identified among 449 suspected febrile persons detected by nested polymerase chain reaction(PCR)assay based on small subunit ribosomal ribonucleic acid(RNA)genes of B.microti and Plasmodium spp.Results:Of all the collected samples from febrile patients,mono-infection with B.microti,P.vivax,P.falciparum,and P.malariae accounted for 1.8%(8/449),9.8%(44/449),2.9%(13/449),and 0.2%(1/449),respectively.The rate of mixed infections of B.microti with P.falciparum or P.vivax are both 0.2%(1/449),and mixed infections of P.falciparum and P.vivax accounted for 1.1%(5/449).Conclusions:This report supports the hypothesis that babesiosis caused by B.microti is emerging along the China-Myanmar border in the Yunnan province,P.R.China,but it was ignored because of low parasitemia or mixed infection with Plasmodium spp.More sensitive and specific diagnosis methods are needed to find the rapid response mechanism of emergency for babesiosis and malaria co-prevalence areas.
基金supported by the Special Fund for Health Research in the Public Interest,China(Grant No.201202019)the National Key Science&Technology Special Projects on Major Infectious Diseases,China(Grant No.2012ZX10004-211).
文摘Background:Babesiosis is an uncommon but emerging tick-borne disease caused by the genus Babesia.In this case study,we report a case of human infection with a novel Babesia sp.in China.Findings:The patient in question had been suffering from repetitive occurrences of mild fever of unknown origin and fatigue for 10 years.Ring forms,tetrads,and one or two dots of chromatin or trophozoite-like organisms were observed in the patient’s thin blood smears and bone marrow smears.Using a confocal laser-scanning microscope,it was observed that the patient’s serum had reactivity with the surface proteins of the B.microti strain.Electron microscopy revealed oval red blood cells with 1~2μm of knob protrusions in the cellular membrane.The results of the Babesia-specific nested PCR assay for 18S rRNA confirmed the presence of Babesia infection.The construction of a phylogenetic relationship showed clustering with B.microti and B.duncani,which was identified as a novel Babesia species and named as Babesia sp.XXB/HangZhou.Azithromycin,doxycycline,and moxifloxacin hydrochloride were shown to relieve symptoms but were not as effective after continuous usage.After atovaquone(Mepron®)administration,the patient recovered from fever and tested negative for detection of Babesia-specific genes.Conclusion:Babesia sp.XXB/HangZhou is a novel Babesia species,which causes mild babesiosis in an immunocompetent patient.
文摘Background: Babesiosis is an emerging tick-borne zoonotic infectious disease.Babesia microti is responsible for most cases of human babesiosis globally.It is important to investigate the prevalence of B.microti in the mammalian host population of a specific region in order to elucidate mechanisms of pathogen transmission and to define geographic areas where humans face the greatest risk of exposure.The aim of this study is to understand the prevalence and genotypes of B.microti in the small mammals that are found in Beijing,China.Methods:: We trapped small mammals from all of the 16 urban,suburban,and outer suburban districts of Beijing during the years 2014,2017 and 2018.Genomic DNA was extracted from the heart tissues individually and the Babesia 18S rRNA gene was detected by PCR.The genotypes of B.microti were identified based on sequence alignments and phylogenetic analysis.The morphology of the parasites was observed under light microscopy.The risk factors were analyzed statistically based on both univariate analyses and multivariate logistic regression.Results: A total of 1391 small mammals were collected.Positive infection of B.microti was detected in 12.1%(168/1391)of small mammals from 15 out of the 16 districts.Both Kobe-type and U.S.-type B.microti,accounting for 9.5%and 2.7%,respectively,were identified.Classic diverse morphologic forms of B.microti were observed.Specific types of ecological habitats including shrub areas,broad-leaved forest,and cropland were revealed to be risk factors associated with B.microti infection.Conclusions: This study demonstrated the wide prevalence of B.microti infection in eight species of small mammals in Beijing,with Kobe-type more prevalent than U.S.-type.This study provides fundamental information for the development of informed prevention and control measures by public health authorities;the data gathered indicates a need for further monitoring of both clinical diseases in individuals presenting with babesiosis-like symptoms,as well as the infection status of ticks in high risk areas.
基金supported by the State Key Research Development Program of China(2019YFC1200501)State Key Program of Infectious Diseases(2017ZX10303404)Natural Science Foundation of China(81673235 and 81621005).
文摘The emerging Babesia venatorum upsurges as a potential health threat occurring in China and other endemic countries.Few attempts to isolate and culture the Babesia species had been conducted in vitro.We collected the questing Ixodes persulcatus from identified endemic areas and allowed them to feed on the severe combined immunodeficiency(SCID)mice.The positive mice were chosen to provide positive erythrocytes with asexual B.venatorum for continuous culture in mouse or human erythrocytes in vitro,with RPMI 1640 medium and appropriate serum.With B.venatorum in the SCID mice,erythrocytes were cultured in vitro for confirmation by morphological observations with transmission electron microscopes.Sequences of B.venatorum were then identified by way of conventional PCR amplification.Parasitemia counts monitored the growth of B.venatorum on thin blood smears and real-time quantitative PCR in parallel.As expected,B.venatorum positive mice were harvested by sufficient attacks of I.persulcatus ticks.The erythrocytes of the infected mice were then inoculated and successfully cultured in donated erythrocytes from humans and mice in RPMI 1640 culture medium.Active growth of B.venatorum was well demonstrated in human erythrocytes with 3.3 times parasite-load when compared with a mouse under similar conditions.With the increased subcultures,a prolonged period of detectable parasitemia with much higher peak parasitemia and shorter time to reach peak parasitemia were observed in the following subcultures.A new strategy for isolation and in vitro culture of B.venatorum has been provided with a continuous supply of sufficient pathogens to satisfy human babesiosis's testings and clinical therapies.
