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Ticks and Tick-borne Diseases Nov 2023Babesia microti is a tick-transmitted protozoan parasite of wildlife that can also cause serious disease in humans. It is now well established that B. microti represents...
Babesia microti is a tick-transmitted protozoan parasite of wildlife that can also cause serious disease in humans. It is now well established that B. microti represents an assemblage of different strains or species, only some of which are important zoonotic pathogens. Therefore, in order to assess the potential public health risk associated with B. microti in any given location, it is important to determine the strains that are present. This is the first study on the presence and identity of B. microti in Ireland. Overall, 314 wood mice (Apodemus sylvaticus), 243 bank voles (Myodes glareolus) and 634 questing Ixodes ricinus nymphs collected in various locations across Ireland were screened for the presence of B. microti by metabarcoding and nested PCR, respectively. Overall 8 rodent spleen samples (1.4%) were positive for B. microti, while all tick samples tested negative. Rodent isolates were identified as the 'Munich' strain which rarely causes human disease and is chiefly transmitted by the mouse tick, Ixodes trianguliceps. Together with reports from the UK these results suggest that B. microti does not represent a significant public health risk in Britain or Ireland.
Topics: Animals; Humans; Mice; Babesia microti; Ireland; Ixodes; Animals, Wild; Murinae; Arvicolinae
PubMed: 37406478
DOI: 10.1016/j.ttbdis.2023.102221 -
Transfusion Oct 2021Babesia microti has gained a foothold in Canada as tick vectors become established in broader geographic areas. B. microti infection is associated with mild or no...
BACKGROUND
Babesia microti has gained a foothold in Canada as tick vectors become established in broader geographic areas. B. microti infection is associated with mild or no symptoms in healthy individuals but is transfusion-transmissible and can be fatal in immunocompromised individuals. This is the first estimate of clinically significant transfusion-transmitted babesiosis (TTB) risk in Canada.
STUDY DESIGN AND METHODS
The proportion of B. microti-antibody (AB)/nucleic acid amplification test (NAT)-positive whole blood donations was estimated at 5.5% of the proportion of the general population with reported Lyme Disease (also tick-borne) based on US data. Monte Carlo simulation estimated the number and proportion of infectious red cell units for three scenarios: base, localized incidence (risk in Manitoba only), and donor study informed (prevalence from donor data). The model simulated 1,029,800 donations repeated 100,000 times for each.
RESULTS
In the base scenario 0.5 (0.01, 1.75), B. microti-NAT-positive donations would be expected per year, with 0.08 (0, 0.38) recipients suffering clinically significant TTB (1 every 12.5 years). In the localized incidence scenario, there were 0.21(0, 0.7) B. microti-NAT-positive donations, with 0.04 (0, 0.14) recipient infections (about 1 every 25 years). In the donor study informed scenario, there were 4.6 (0.3, 15.8) B. microti-NAT-positive donations expected, and 0.81 (0.05, 3.14) clinically significant TTB cases per year.
DISCUSSION
The likelihood of clinically relevant TTB is low. Testing would have very little utility in Canada at this time. Ongoing pathogen surveillance in tick vectors is important as B. microti prevalence appears to be slowly increasing in Canada.
Topics: Babesia microti; Babesiosis; Blood Donors; Blood Transfusion; Canada; Humans; Monte Carlo Method; Risk Factors; Transfusion Reaction
PubMed: 34272882
DOI: 10.1111/trf.16595 -
Journal of Vector Borne Diseases 2020For detection and molecular characterization of Babesia microti in laboratory mice from India.
BACKGROUND & OBJECTIVES
For detection and molecular characterization of Babesia microti in laboratory mice from India.
METHODS
A total of 625 mice were screened by peripheral blood smear examination and subsequently was confirmed by PCR using a piroplasm conserved primer set (Piro A/B). Nested PCR was done using a species-specific primer targeting the gene encoding the small subunit ribosomal RNA (18S rRNA). The PCR products were cloned, purified and sequenced. A total of 12 isolates were obtained. The sequences were aligned and phylogenetic trees were prepared with other published Babesia spp. sequences.
RESULTS
B. microti was detected with a total infection rate of 8.80%. The higher rate of infection was observed by species specific PCR (8.80%) than examined by blood smear (7.20%). Sequence and phylogenetic analysis showed that Babesia species detected in mice were genetically identical to the genotypes of B. microti and can be easily distinguished from other genotypes of Babesia parasites by neighbour joining and maximum likelihood method. Intra-species analysis indicated that all the twelve isolates from six North-Eastern states of India have a close identity but inter-species showed genetic reservoir host for transmission of babesial infection to humans.
INTERPRETATION & CONCLUSION
The detection of Babesia microti may suggest that laboratory mice may serve as potential reservoir host for human infection and possibility of innovative way of diagnosing and control of human babesiosis.
Topics: Animals; Babesia; Babesia microti; Babesiosis; Mice; Phylogeny; RNA, Ribosomal, 18S
PubMed: 34472511
DOI: 10.4103/0972-9062.310867 -
Frontiers in Cellular and Infection... 2022Babesiosis poses a serious threat to immunocompromised individuals and the major etiological species of for human babesiosis is . Merozoites are a critical stage in the...
Babesiosis poses a serious threat to immunocompromised individuals and the major etiological species of for human babesiosis is . Merozoites are a critical stage in the life cycle of . Several merozoite proteins have been demonstrated to play important roles in this process; however, most of the merozoite proteins of remain unknown. In the present study, we identified a novel merozoite protein of with similar structure to the thioredoxin (Trx)-like domain of the Trx family, which was named as Trx-like protein (TLP). Western blot assays demonstrated that this protein was expressed by during the erythrocytic infection process, and its expression peaked on day 7 post-infection . Immunofluorescence assay further showed that this protein is mainly expressed in merozoites. TLP hold both heparin- and erythrocyte-binding properties, which are critical functions of invasion-related proteins. Immunization with recombinant TLP imparted significant protection against infection in mice. Taken together, these results suggest that the novel merozoite protein, TLP, is an important pathogenic molecule of and may be a possible target for the design of babesiosis control strategy.
Topics: Animals; Babesia microti; Babesiosis; Mice; Protozoan Proteins; Thioredoxins; Virulence
PubMed: 35252036
DOI: 10.3389/fcimb.2022.826818 -
Frontiers in Immunology 2020Babesiosis caused by species imposes an increasing threat to public-health and so far, there is no effective vaccine to prevent infections. surface antigen may...
Babesiosis caused by species imposes an increasing threat to public-health and so far, there is no effective vaccine to prevent infections. surface antigen may participate in the invasion of erythrocytes. In our previous study, a surface antigen of merozoites, named as SP44 was identified as a dominant reactive antigen by protein microarray screening. To evaluate its potential applications in diagnosis and prevention of Babesiosis, the open reading frame encoding SP44 was cloned and the recombinant protein was expressed. In consistent with the protein microarray result, recombinant SP44 (rSP44) can be recognized by sera from infected mice. Immunofluorescence assays (IFA) confirmed that SP44 is a secreted protein and localized principally in the cytoplasm of the parasites. The parasitemia and gene copies were lower in mice administered rSP44 antisera compared with normal controls. Active immunization with rSP44 also afforded protection against infection. The concentrations of hemoglobin in rSP44 immunization group were higher than those in the control group. Importantly, vaccination of mice with rSP44 resulted in a Th1/Th2 mixed immune response with significantly elevated IL-10 and IFN-γ levels during the early stage of infection. Taken together, our results indicated that rSP44 can induce a protective immune response against infection. Thus, SP44 can be used as both a diagnosis marker and a vaccine candidate.
Topics: Animals; Antibodies, Protozoan; Antigens, Protozoan; Babesia microti; Babesiosis; Cloning, Molecular; Disease Models, Animal; Disease Resistance; Female; Hemoglobins; Humans; Immunity, Cellular; Merozoites; Mice; Mice, Inbred BALB C; Protein Array Analysis; T-Lymphocytes, Helper-Inducer; Vaccination
PubMed: 32733477
DOI: 10.3389/fimmu.2020.01437 -
Journal of Medical Entomology Oct 2019Babesia microti (Aconoidasida: Piroplasmida) (Franca, 1910) is an important tick-borne zoonotic parasite with rodents serving as reservoir hosts. In the present study,...
Babesia microti (Aconoidasida: Piroplasmida) (Franca, 1910) is an important tick-borne zoonotic parasite with rodents serving as reservoir hosts. In the present study, 536 rodents were captured from Burdur, Bartin, Giresun, and Yozgat provinces of Turkey between the years 2010 and 2012, and blood samples were examined for the presence of Babesia spp. using conventional PCR which targeted the 18S rRNA gene. The sequence analysis of PCR amplicons was tested for B. microti as well as for Hepatozoon spp., and Sarcocystis spp. Overall, 5.8% of the rodents were positive for B. microti: 41% in Myodes glareolus, 7.7% in Chionomys roberti, and 2% in Apodemus spp., whereas no Babesia DNA was detected in Mus macedonicus and Microtus spp. Six rodents were positive for Hepatozoon spp. and one rodent was positive for Sarcocystis spp. Overall, 14.9 and 4.5% of rodents captured from Bartin and Giresun provinces, respectively, were PCR positive for B. microti, whereas none of rodents captured in Burdur and Yozgat were positive for Babesia spp. The sequence data of B. microti from rodents revealed that all sequences belonged to the zoonotic genotype. Sequences of B. microti obtained from rodents of the Bartin province were genotypically closer to European isolates, whereas those obtained from rodents of the Giresun province were closer to Russian and Mongolian isolates.
Topics: Animals; Babesia microti; Babesiosis; Prevalence; Rodent Diseases; Rodentia; Species Specificity; Turkey
PubMed: 31143936
DOI: 10.1093/jme/tjz084 -
Infectious Diseases of Poverty Nov 2020Babesiosis is an emerging tick-borne zoonotic infectious disease. Babesia microti is responsible for most cases of human babesiosis globally. It is important to...
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.
Topics: Animals; Babesia microti; Babesiosis; Beijing; DNA, Protozoan; Disease Reservoirs; Female; Genotype; Humans; Male; Mammals; Phylogeny; Polymerase Chain Reaction; Prevalence; RNA, Ribosomal, 18S; Risk Factors; Ticks; Zoonoses
PubMed: 33176879
DOI: 10.1186/s40249-020-00775-3 -
Emerging Infectious Diseases Mar 2023We report a case of Babesia microti infection in an immunocompetent child <5 years of age that caused fever and severe intravascular hemolysis. Physicians in China...
We report a case of Babesia microti infection in an immunocompetent child <5 years of age that caused fever and severe intravascular hemolysis. Physicians in China should be aware of babesiosis, especially in the differential diagnosis of immune hemolytic anemia with negative results for antiglobulin tests.
Topics: Humans; Child; Babesia microti; Hemolysis; Babesiosis; China; Fever
PubMed: 36823712
DOI: 10.3201/eid2903.220888 -
Parasites & Vectors Mar 2021Protozoa in the genus Babesia are transmitted to humans through tick bites and cause babesiosis, a malaria-like illness. Vertical transmission of Babesia spp. has been...
BACKGROUND
Protozoa in the genus Babesia are transmitted to humans through tick bites and cause babesiosis, a malaria-like illness. Vertical transmission of Babesia spp. has been reported in mammals; however, the exact timing and mechanisms involved are not currently known. The aims of this study were to evaluate the success of vertical transmission of B. microti in female mice infected before pregnancy (mated during the acute or chronic phases of Babesia infection) and that of pregnant mice infected during early and advanced pregnancy; to evaluate the possible influence of pregnancy on the course of parasite infections (parasitaemia); and to assess pathological changes induced by parasitic infection.
METHODS
The first set of experiments involved two groups of female mice infected with B. microti before mating, and inseminated on the 7th day and after the 40th day post infection. A second set of experiments involved female mice infected with B. microti during pregnancy, on the 4th and 12th days of pregnancy. Blood smears and PCR targeting the 559 bp 18S rRNA gene fragment were used for the detection of B. microti. Pathology was assessed histologically.
RESULTS
Successful development of pregnancy was recorded only in females mated during the chronic phase of infection. The success of vertical transmission of B. microti in this group was 63%. No evidence of pregnancy was found in females mated during the acute phase of infection or on the 4th day of pregnancy. In the group infected on the 12th day of pregnancy, numerous complications including loss of pregnancy and stillbirths were recorded. During the acute phase of infection, parasitaemia was lower in pregnant females in comparison to infected, non-pregnant control females.
CONCLUSIONS
Acute B. microti infection prevents the initiation of pregnancy and embryonic development if it occurs during the first trimester, and causes severe complications in foetal BALB/c mice in the second and third trimesters of pregnancy. Chronic B. microti infection has no detrimental impact on the initiation and development of pregnancy, but results in congenital infection of the offspring. Further study is required to determine the extent to which maternal anti-babesial immune responses contribute to compromise pregnancy in the murine model of congenital Babesia infection.
Topics: Animals; Babesia microti; Babesiosis; Disease Models, Animal; Embryonic Development; Female; Infectious Disease Transmission, Vertical; Male; Mice; Mice, Inbred BALB C; Parasitemia; Pregnancy; RNA, Ribosomal, 18S
PubMed: 33653384
DOI: 10.1186/s13071-021-04638-0 -
Parasitology Research Sep 2020Babesiosis is a tick-borne protozoonosis caused by Babesia, which can cause fever, hemolytic anemia, hemoglobinuria, and even death. Babesia microti is a parasite found...
Babesiosis is a tick-borne protozoonosis caused by Babesia, which can cause fever, hemolytic anemia, hemoglobinuria, and even death. Babesia microti is a parasite found in rodents and can be pathogenic to humans. In this study, the full-length cDNA of a B. microti cysteine protease (BmCYP) was expressed and the recombinant rBmCYP protein analyzed and characterized. BmCYP is encoded by an ORF of 1.3 kb, with a predicted molecular weight of 50 kDa and a theoretical pI of 8.5. The amino acid sequence of BmCYP exhibits an identity of 32.9 to 35.2% with cysteine proteases of Babesia ovis, Babesia bovis, and Theileria, respectively. The results of the proteinase assays show that rBmCYP has cysteine protease enzymatic activity. In addition, we demonstrate that tick cystatins rRhcyst-1 and rRhcyst-2 were able to effectively inhibit the activity of rBmCYP; the inhibition rates were 57.2% and 30.9%, respectively. Tick cystatins Rhcyst-1 and Rhcyst-2 were differentially expressed in ticks that fed on Babesia-infected mice relative to non-infected control ticks. Our results suggest that BmCYP is a functional enzyme with cysteine protease enzymatic activity and may be involved in tick-B. microti interactions.
Topics: Amino Acid Sequence; Animals; Arthropod Proteins; Babesia bovis; Babesia microti; Babesiosis; Cystatins; Cysteine Proteases; Humans; Mice; Mice, Inbred BALB C; Protein Binding; Protozoan Proteins; Ticks
PubMed: 32740752
DOI: 10.1007/s00436-020-06818-w