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Pathogens (Basel, Switzerland) Nov 2021The biology of intraerythrocytic parasites presents unique challenges for the diagnosis of human babesiosis. Antibody-based assays are highly sensitive but fail to... (Review)
Review
The biology of intraerythrocytic parasites presents unique challenges for the diagnosis of human babesiosis. Antibody-based assays are highly sensitive but fail to detect early stage infections prior to seroconversion (window period) and cannot distinguish between an active infection and a previously resolved infection. On the other hand, nucleic acid-based tests (NAT) may lack the sensitivity to detect window cases when parasite burden is below detection limits and asymptomatic low-grade infections. Recent technological advances have improved the sensitivity, specificity and high throughput of NAT and the antibody-based detection of . Some of these advances include genomics approaches for the identification of novel high-copy-number targets for NAT and immunodominant antigens for superior antigen and antibody-based assays for . Future advances would also rely on next generation sequencing and CRISPR technology to improve detection. This review article will discuss the historical perspective and current status of technologies for the detection of , the most common species causing human babesiosis in the United States, and their implications for early diagnosis of acute babesiosis, blood safety and surveillance studies to monitor areas of expansion and emergence and spread of species and their genetic variants in the United States and globally.
PubMed: 34959518
DOI: 10.3390/pathogens10121563 -
Parasites & Vectors Nov 2022The Babesia microti-like parasite is an emerging tick-borne piroplasm that has been detected in a range of hosts worldwide. Babesia vulpes, which is found in dogs and...
BACKGROUND
The Babesia microti-like parasite is an emerging tick-borne piroplasm that has been detected in a range of hosts worldwide. Babesia vulpes, which is found in dogs and foxes, has been reclassified from B. microti-like parasites. The relationships among these B. microti-like parasites and B. vulpes with respect to host range and geographical origin have not been elucidated.
METHODS
Blood samples were collected from 27 raccoon dogs in South Korea and used to screen for B. microti-like parasites based on a PCR assay targeting the 18S rRNA gene of Babesia. For comparative purposes, in addition to 18S rRNA sequences from nine raccoon dogs, we also analyzed 18S rRNA sequences from B. microti-like parasites infecting hosts in different geographical regions worldwide obtained from the GenBank database, giving 123 sequences in total. The genetic variation and evolutionary relationships among these sequences were examined based on analyses using DnaSP, MEGA, Arlequine, and BEAST software.
RESULTS
Babesia microti-like parasites were identified in nine raccoon dogs and found to be related to B. vulpes obtained from Spanish dogs. Among the 123 sequences from 14 countries and various hosts, we identified 43 haplotypes with high genetic variance. Based on the genetic variance and phylogenetic analyses, we established that the B. microti-like parasites isolated in different geographical regions and from hosts belonging to five orders showed higher among-population variation than within-population variation. Babesia vulpes parasites infecting carnivore hosts, including raccoon dogs, foxes, skunks and dogs, appear to be genetically distinct from B. microti-like parasites infecting hosts belonging to the other orders.
CONCLUSIONS
Our study demonstrated the genetic variation and evolutionary relationships among 18S rRNA sequences obtained from blood samples collected from various hosts and different geographical regions. Babesia vulpes was identified from raccoon dogs in South Korea. In addition, higher genetic variations were observed among populations of different hosts and geographical origins and, in particular, low connectivity was observed among host populations in the order Carnivora and those in other orders. These results suggest the B. vulpes, a piroplasmid species pathogenic in domestic dogs and wild canines, is genetically and evolutionarily different from B. microti-like parasites.
Topics: Animals; Babesia; Babesia microti; Parasites; Babesiosis; RNA, Ribosomal, 18S; Foxes; Phylogeny; Raccoon Dogs
PubMed: 36329533
DOI: 10.1186/s13071-022-05528-9 -
Clinical Microbiology Reviews Jul 2000Babesiosis is an emerging, tick-transmitted, zoonotic disease caused by hematotropic parasites of the genus Babesia. Babesial parasites (and those of the closely related... (Review)
Review
Babesiosis is an emerging, tick-transmitted, zoonotic disease caused by hematotropic parasites of the genus Babesia. Babesial parasites (and those of the closely related genus Theileria) are some of the most ubiquitous and widespread blood parasites in the world, second only to the trypanosomes, and consequently have considerable worldwide economic, medical, and veterinary impact. The parasites are intraerythrocytic and are commonly called piroplasms due to the pear-shaped forms found within infected red blood cells. The piroplasms are transmitted by ixodid ticks and are capable of infecting a wide variety of vertebrate hosts which are competent in maintaining the transmission cycle. Studies involving animal hosts other than humans have contributed significantly to our understanding of the disease process, including possible pathogenic mechanisms of the parasite and immunological responses of the host. To date, there are several species of Babesia that can infect humans, Babesia microti being the most prevalent. Infections with Babesia species generally follow regional distributions; cases in the United States are caused primarily by B. microti, whereas cases in Europe are usually caused by Babesia divergens. The spectrum of disease manifestation is broad, ranging from a silent infection to a fulminant, malaria-like disease, resulting in severe hemolysis and occasionally in death. Recent advances have resulted in the development of several diagnostic tests which have increased the level of sensitivity in detection, thereby facilitating diagnosis, expediting appropriate patient management, and resulting in a more accurate epidemiological description.
Topics: Animals; Babesia; Babesiosis; Disease Susceptibility; Humans; Phylogeny; Protozoan Vaccines; Vaccines, Synthetic
PubMed: 10885987
DOI: 10.1128/CMR.13.3.451 -
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 -
Pathogens (Basel, Switzerland) Sep 2021Babesiosis is an emerging tick-borne disease caused by apicomplexan parasites of the genus . With its increasing incidence worldwide and the risk of human-to-human... (Review)
Review
Babesiosis is an emerging tick-borne disease caused by apicomplexan parasites of the genus . With its increasing incidence worldwide and the risk of human-to-human transmission through blood transfusion, babesiosis is becoming a rising public health concern. The current arsenal for the treatment of human babesiosis is limited and consists of combinations of atovaquone and azithromycin or clindamycin and quinine. These combination therapies were not designed based on biological criteria unique to parasites, but were rather repurposed based on their well-established efficacy against other apicomplexan parasites. However, these compounds are associated with mild or severe adverse events and a rapid emergence of drug resistance, thus highlighting the need for new therapeutic strategies that are specifically tailored to parasites. Herein, we review ongoing babesiosis therapeutic and management strategies and their limitations, and further review current efforts to develop new, effective, and safer therapies for the treatment of this disease.
PubMed: 34578153
DOI: 10.3390/pathogens10091120 -
Pathogens (Basel, Switzerland) Sep 2021Fifty years ago, the index case of human babesiosis due to was diagnosed in a summer resident of Nantucket Island. Human babesiosis, once called "Nantucket fever" due... (Review)
Review
Fifty years ago, the index case of human babesiosis due to was diagnosed in a summer resident of Nantucket Island. Human babesiosis, once called "Nantucket fever" due to its seeming restriction to Nantucket and the terminal moraine islands of southern New England, has emerged across the northeastern United States to commonly infect people wherever Lyme disease is endemic. We review the history of babesiosis on Nantucket, analyze its epidemiology and ecology there, provide summaries of the first case histories, and comment on its future public health burden.
PubMed: 34578191
DOI: 10.3390/pathogens10091159 -
Pathogens (Basel, Switzerland) Nov 2021The effects of current and future global warming on the distribution and activity of the primary ixodid vectors of human babesiosis (caused by , and ) are discussed.... (Review)
Review
The effects of current and future global warming on the distribution and activity of the primary ixodid vectors of human babesiosis (caused by , and ) are discussed. There is clear evidence that the distributions of both , the vector in Europe, and in North America have been impacted by the changing climate, with increasing temperatures resulting in the northwards expansion of tick populations and the occurrence of at higher altitudes. , which replaces in Eurasia and temperate Asia, is presumed to be the babesiosis vector in China and Japan, but this tick species has not yet been confirmed as the vector of either human or animal babesiosis. There is no definite evidence, as yet, of global warming having an effect on the occurrence of human babesiosis, but models suggest that it is only a matter of time before cases occur further north than they do at present.
PubMed: 34832586
DOI: 10.3390/pathogens10111430 -
Current Opinion in Hematology Nov 2016This review summarizes the current status of blood screening to prevent transfusion-transmitted babesiosis (TTB). (Review)
Review
PURPOSE OF REVIEW
This review summarizes the current status of blood screening to prevent transfusion-transmitted babesiosis (TTB).
RECENT FINDINGS
Babesia microti has recently been determined to be the most common transfusion-transmitted pathogen in the United States. Patients who acquire TTB often experience severe illness with an associated mortality rate of about 20%. Recent studies have demonstrated that laboratory screening using B. microti antibody and/or PCR assays can effectively identify infectious blood donors and that this approach may offer a cost- effective means of intervention. Pathogen inactivation methods may offer an alternative solution. None of these methods has yet been licensed by US Food and Drug Administration, however, and current efforts to prevent TTB rely on excluding blood donors who report having had babesiosis.
SUMMARY
TTB imposes a significant health burden on the United States population. Further research is needed to better inform decisions on optimal screening strategies and reentry criteria, but given the acute need and the currently available screening tools, initiation of blood donor screening to prevent TTB should be given high priority.
Topics: Babesia microti; Babesiosis; Blood Donors; Cost-Benefit Analysis; Enzyme-Linked Immunosorbent Assay; Fluorescent Antibody Technique; Humans; Mass Screening; Referral and Consultation; Seroepidemiologic Studies; Transfusion Reaction; United States
PubMed: 27537475
DOI: 10.1097/MOH.0000000000000287 -
Pathogens (Basel, Switzerland) Nov 2021Human babesiosis caused by the intraerythrocytic apicomplexan is an expanding tick-borne zoonotic disease that may cause severe symptoms and death in elderly or...
Human babesiosis caused by the intraerythrocytic apicomplexan is an expanding tick-borne zoonotic disease that may cause severe symptoms and death in elderly or immunocompromised individuals. In light of an increasing resistance of to drugs, there is a lack of therapeutic alternatives. Species-specific proteases are essential for parasite survival and possible chemotherapeutic targets. However, the repertoire of proteases in remains poorly investigated. Herein, we employed several combined bioinformatics tools and strategies to organize and identify genes encoding for the full repertoire of proteases in the genome. We identified 64 active proteases and 25 nonactive protease homologs. These proteases can be classified into cysteine ( = 28), serine ( = 21), threonine ( = 14), asparagine ( = 7), and metallopeptidases ( = 19), which, in turn, are assigned to a total of 38 peptidase families. Comparative studies between the repertoire of and proteases revealed differences among sensu stricto and sensu lato parasites that reflect their distinct evolutionary history. Overall, this data may help direct future research towards our understanding of the biology and pathogenicity of parasites and to explore proteases as targets for developing novel therapeutic interventions.
PubMed: 34832610
DOI: 10.3390/pathogens10111457 -
Pathogens (Basel, Switzerland) Jul 2019Persistent infection is a characteristic feature of babesiosis, a worldwide, emerging tick-borne disease caused by members of the genus Persistence of infection in... (Review)
Review
Persistent infection is a characteristic feature of babesiosis, a worldwide, emerging tick-borne disease caused by members of the genus Persistence of infection in reservoir hosts increases the probability of survival and transmission of these pathogens. Laboratory tools to detect in red blood cells include microscopic detection using peripheral blood smears, nucleic acid detection (polymerase chain reaction and transcription mediated amplification), antigen detection, and antibody detection. , the major cause of human babesiosis, can asymptomatically infect immunocompetent individuals for up to two years. Chronically infected blood donors may transmit the pathogen to another person through blood transfusion. Transfusion-transmitted babesiosis causes severe complications and death in about a fifth of cases. Immunocompromised patients, including those with asplenia, HIV/AIDS, malignancy, or on immunosuppressive drugs, often experience severe disease that may relapse up to two years later despite anti- therapy. Persistent infection is promoted by immune evasive strategies and impaired host immune mechanisms. The health burden of persistent and recrudescent babesiosis can be minimized by development of novel therapeutic measures, such as new anti-parasitic drugs or drug combinations, improved anti-parasitic drug duration strategies, or immunoglobulin preparations; and novel preventive approaches, including early detection methods, tick-avoidance, and blood donor screening.
PubMed: 31319461
DOI: 10.3390/pathogens8030102