Human Babesiosis: Pathogens, Prevalence, Diagnosis and Treatment

Babesia bigemina (smith and Kilbourne, 1893) detection in Amblyomma sculptum (Berlese, 1888) ticks in the Mato Grosso do Sul state, Brazil

Ticks parasitize various hosts, including humans, and are known to transmit pathogens that can be harmful not only to animals but also to humans. To evaluate the possible presence of pathogens in ticks, we aimed to collect and identify tick fauna specimens in Lagoa Comprida Municipal Natural Park, an anthropogenic urban area located in Aquidauana, Mato Grosso do Sul, Brazil. A total of 1216 ticks, of which 51.2% were Amblyomma sculptum, 1.2% were Amblyomma dubitatum, and 41% were Amblyomma spp. were collected. These results show that the prevalence of A. sculptum is significantly higher than that of A. dubitatum across all four seasons. Molecular analyses revealed positive samples for the genus Babesia, including the confirmation of Babesia bigemina in an A. sculptum specimen, marking the first record of this relationship. This unexpected finding demands greater attention and deeper analysis in the context of the epidemiology of tick-borne diseases.

Continuous in vitro propagation of Babesia microti

The currently accepted initiation of Babesia infection describes a sporozoite stage infused into the host, along with other saliva components, by the tick vector. This sporozoite can enter and initiate erythrocyte infection directly. In the particular case of Babesia microti, however, that sporozoite loses the ability to further propagate in vitro once deprived of its natural host. True B. sensu stricto do not require the host collaboration described in this study. Hence it has become a current topic of research involving B. microti (B. sensu lato), a rather unique species that requires host collaboration to maintain an erythrocyte propagation cycle. The main attachment protein is synthesized by this parasite in excess and exported to the host from the erythrocyte infrastructure to immunize the host at all stages of infection. The synthesis of host immune IgM antibody is necessary for the propagation of B. microti, being central to entry into uninfected host erythrocytes. Sequential use of the host immune system then involves complement factor C3b to complete the three-part assembly necessary to initiate the rhoptry sequence for invasion of uninfected erythrocytes and further propagation. These several components must be furnished within the in vitro culture medium and the sequence of these reactions is discussed. The corollary view of the parasite survival versus the host immune defenses is also discussed as it involves the same host factors promoting continuing parasite growth. This is the first description of continuous in vitro propagation of B. microti.

Properties and predicted functions of large genes and proteins of apicomplexan parasites

Evolutionary constraints greatly favor compact genomes that efficiently encode proteins. However, several eukaryotic organisms, including apicomplexan parasites such as Toxoplasma gondii, Plasmodium falciparum and Babesia duncani, the causative agents of toxoplasmosis, malaria and babesiosis, respectively, encode very large proteins, exceeding 20 times their average protein size. Although these large proteins represent <1% of the total protein pool and are generally expressed at low levels, their persistence throughout evolution raises important questions about their functions and possible evolutionary pressures to maintain them. In this study, we examined the trends in gene and protein size, function and expression patterns within seven apicomplexan pathogens. Our analysis revealed that certain large proteins in apicomplexan parasites harbor domains potentially important for functions such as antigenic variation, erythrocyte invasion and immune evasion. However, these domains are not limited to or strictly conserved within large proteins. While some of these proteins are predicted to engage in conventional metabolic pathways within these parasites, others fulfill specialized functions for pathogen-host interactions, nutrient acquisition and overall survival.

Tick-Borne Diseases of Humans and Animals in West Africa

Ticks are a significant group of arthropod vectors that transmit a large variety of pathogens responsible for human and animal diseases worldwide. Ticks are the second biggest transmitters of vector-borne diseases, behind mosquitoes. However, in West Africa, there is often only limited knowledge of tick-borne diseases. With the scarcity of appropriate diagnostic services, the prevalence of tick-borne diseases is generally underestimated in humans. In this review, we provide an update on tick-borne pathogens reported in people, animals and ticks in West Africa by microscopic, immunological and molecular methods. A systematic search was conducted in PubMed and Google Scholar. The selection criteria included all studies conducted in West Africa reporting the presence of Rickettsia, Borrelia, Anaplasma, Ehrlichia, Bartonella, Coxiella burnetii, Theileria, Babesia, Hepatozoon and Crimean-Congo haemorrhagic fever viruses in humans, animals or ticks. Our intention is to raise awareness of tick-borne diseases amongst human and animal health workers in West Africa, and also physicians working with tourists who have travelled to the region.

Molecular epidemiological investigation of piroplasms carried by pet cats and dogs in an animal hospital in Guiyang, China

Piroplasmosis is a zoonotic disease mainly caused by the Babesia and Theileria parasites. Piroplasmosis is often a subclinical infection in dogs and cats that is difficult to detect and is often suspected when clinical signs such as anemia are present. It has been reported to be prevalent in China. However, molecular evidence of the disease has not been reported in pet dogs and cats in Guiyang. In this study, we collected 307 anticoagulated blood samples from an animal hospital in the Wudang District of Guiyang during the period March 2021 to November 2021 and extracted DNA from the samples. The 18S rDNA gene was amplified using PCR, and the positive amplification product was sequenced. The sequences were then analyzed for homology and phylogeny. Of the 307 samples collected, 164 were feline and 143 were canine, with a total of 23 amplifying a target band of approximately 400 bp. The percentage of positives of piroplasms infection in pet cats was 4.27% (7/164), with the pathogens being T. uilenbergi (3) and T. luwenshuni (4). One Colpodella sp. and two undetermined species were also detected in the cat samples. The percentage of positives of piroplasms infection in pet dogs was 7.69% (11/143), with the pathogen being T. uilenbergi (11). One Colpodella sp. was also detected in the dog samples. The results confirmed that T. uilenbergi and T. luwenshuni are prevalent in pet cats and dogs in this area. In addition, the study found a rare zoonotic pathogen, Colpodella sp., in cats and dogs. Therefore, this study is expected to serve as a valuable reference for decision-making regarding animal health management and public health work.

Recombinant protein immunoblots for differential diagnosis of tick-borne relapsing fever and Lyme disease

Lyme disease (LD) is caused by a group of tick-borne bacteria of the genus Borrelia termed Lyme disease Borreliae (LDB). The detection of serum antibodies to specific LDB antigens is widely used to support diagnosis of LD. Recent findings highlight a need for serological tests that can differentiate LD from tick-borne relapsing fever (TBRF) caused by a separate group of Borrelia species termed relapsing fever Borreliae. This is because LD and TBRF share some clinical symptoms and can occur in overlapping locations. The development of serological tests for TBRF is at an early stage compared with LD. This article reviews the application of line immunoblots (IBs), where recombinant proteins applied as lines on nitrocellulose membrane strips are used to detect antibodies in patient sera, for the diagnosis and differentiation of LD and TBRF.

A high-resolution melting approach for the simultaneous differentiation of five human babesiosis-causing Babesia species

BACKGROUND

Six species of apicomplexan parasites of the genus Babesia, namely B. microti, B. divergens, B. duncani, B. motasi, B. crassa-like and B. venatorum, are considered to be the primary causal agents of human babesiosis in endemic areas. These six species possess variable degrees of virulence for their primary hosts. Therefore, the accurate identification of these species is critical for the adoption of appropriate therapeutic strategies.

METHODS

We developed a real-time PCR-high-resolution melting (qPCR-HRM) approach targeting 18S ribosomal RNA gene of five Babesia spp. based on melting temperature (Tm) and genotype confidence percentage values. This approach was then evaluated using 429 blood samples collected from patients with a history of tick bites, 120 DNA samples mixed with plasmids and 80 laboratory-infected animal samples.

RESULTS

The sensitivity and specificity of the proposed qPCR-HRM method were 95% and 100%, respectively, and the detection limit was 1-100 copies of the plasmid with the cloned target gene. The detection level depended on the species of Babesia analyzed. The primers designed in this study ensured not only the high interspecific specificity of our proposed method but also a high versatility for different isolates from the same species worldwide. Additionally, the Tm obtained from the prepared plasmid standard is theoretically suitable for identifying isolates of all known sequences of the five Babesia species.

CONCLUSIONS

The developed detection method provides a useful tool for the epidemiological investigation of human babesiosis and pre-transfusion screening.

Babesiosis concurrent with multiple abscesses from Staphylococcus aureus infection: A case report

Background

Babesiosis is a tick-borne illness. These patients may have signs of a systemic inflammatory response, but abscess formation is unusual. Multiple abscesses in a patient with confirmed babesiosis is very rare, so concurrent infection by another pathogen should be considered.

Case presentation

We report a 42-year-old male patient who had fever, chills, joint pain, abdominal pain, and altered mental status after a possible tick bite on his right foot while fishing in a river. The laboratory tests, including a blood smear, suggested babesiosis. Imaging studies showed multiple brain and spleen abscesses due to Staphylococcus aureus based on the results of a blood culture and next-generation sequencing. The patient eventually recovered after treatment with azithromycin, fosfomycin, and vancomycin.

Conclusion

Concurrent bacterial infection can occur in a patient with babesiosis. Additional tests should be performed when a babesiosis patient presents with signs inconsistent with Babesia infection. Prompt and appropriate treatment is necessary and may be life-saving for these patients.

The Use of Natural Bioactive Nutraceuticals in the Management of Tick-Borne Illnesses

The primary objective of this paper is to provide an evidence-based update of the literature on the use of bioactive phytochemicals, nutraceuticals, and micronutrients (dietary supplements that provide health benefits beyond their nutritional value) in the management of persistent cases of Borrelia burgdorferi infection (Lyme disease) and two other tick-borne pathogens, Babesia and Bartonella species. Recent studies have advanced our understanding of the pathophysiology and mechanisms of persistent infections. These advances have increasingly enabled clinicians and patients to utilize a wider set of options to manage these frequently disabling conditions. This broader toolkit holds the promise of simultaneously improving treatment outcomes and helping to decrease our reliance on the long-term use of pharmaceutical antimicrobials and antibiotics in the treatment of tick-borne pathogens such as Borrelia burgdorferi, Babesia, and Bartonella.

A Forty-Year Analysis of the Literature on Babesia Infection (1982-2022): A Systematic Bibliometric Approach

Babesia infection is a tick-borne protozoan disease associated with significant veterinary, economic, and medical importance. This infection affects many hosts, ranging from wild to domestic animals and including man. All vertebrates serve as potential carriers due to the huge diversity of the species. Babesiosis has been associated with severe economic loss in livestock production, especially in cattle farming, and is also a major public health concern in man, which could be fatal. The infection is usually opportunistic, ranging from asymptomatic to symptomatic, usually in immunocompromised subjects or under conditions of stressful management. This study was designed to uncover trends in relation to publication growth and further explore research output regarding babesiosis from data indexed in the WoS. The WoS is the only platform used to map publications on Babesia infection. The search term "babesiosis" or "Babesia infection" was used to extract articles published across the study period from 1982 to 2022. The inclusion criteria were restricted to only articles for the analysis. The results from the search query showed that a total of 3763 articles were published during the study period with an average of 91.70 ± 43.87 articles annually and an average total citation (n = 1874.8). An annual growth rate of 2.5% was recorded during the study period. The year 2021 had the highest number of published articles (n = 193, 5.1%) and citations (n = 7039). The analysis of the most relevant keywords and titles showed that infection (n = 606, 16.1%), babesiosis (n = 444, 11.7%), and Babesia (n = 1302, 16%) were the most relevant keyword plus (ID), author keyword (DE), and title, respectively. The common conceptual framework analysis through K-means clustering showed two clusters comprising 4 and 41 elements, respectively. The United States of America is the top-performing country in terms of article production (n = 707, 20.8%) and the leading funder for babesiosis research, with two of its agencies ranked at the top. These are the Department of Health and Human Services (n = 254, 6.7%) and the National Institute of Health (n= 238,6.3%). Igarashi I. is the top-performing author (n = 231, 6.1%), while Veterinary Parasitology is ranked the top journal (n = 393, 10.4%) in terms of babesiosis publications. Overall, an increase in publications was observed in the study period, with significant output from developed nations.

Comparative genomics reveals unique features of two Babesia motasi subspecies: Babesia motasi lintanensis and Babesia motasi hebeiensis

Parasites of the Babesia genus are prevalent worldwide and infect a wide diversity of domestic animals and humans. Herein, using Oxford Nanopore Technology and Illumina sequencing technologies, we sequenced two Babesia sub-species, Babesia motasi lintanensis and Babesia motasi hebeiensis. We identified 3,815 one-to-one ortholog genes that are specific to ovine Babesia spp. Phylogenetic analysis reveals that the two B. motasi subspecies form a distinct clade from other Piroplasma spp. Consistent with their phylogenetic position, comparative genomic analysis reveals that these two ovine Babesia spp. share higher colinearity with Babesia bovis than with Babesia microti. Concerning the speciation date, B. m. lintanensis split from B. m. hebeiensis approximately 17 million years ago. Genes correlated to transcription, translation, protein modification and degradation, as well as differential/specialized gene family expansions in these two subspecies may favor adaptation to vertebrate and tick hosts. The close relationship between B. m. lintanensis and B. m. hebeiensis is underlined by a high degree of genomic synteny. Compositions of most invasion, virulence, development, and gene transcript regulation-related multigene families, including spherical body protein, variant erythrocyte surface antigen, glycosylphosphatidylinositol anchored proteins, and transcription factor Apetala 2 genes, is largely conserved, but in contrast to this conserved situation, we observe major differences in species-specific genes that may be involved in multiple functions in parasite biology. For the first time in Babesia spp., we find abundant fragments of long terminal repeat-retrotransposons in these two species. We provide fundamental information to characterize the genomes of B. m. lintanensis and B. m. hebeiensis, providing insights into the evolution of B. motasi group parasites.

Global Metabolomic Profiling of Host Red Blood Cells Infected with Babesia divergens Reveals Novel Antiparasitic Target Pathways

Babesia divergens is an apicomplexan parasite that infects human red blood cells (RBCs), initiating cycles of invasion, replication, and egress, resulting in extensive metabolic modification of the host cells. Babesia is an auxotroph for most of the nutrients required to sustain these cycles. There are currently limited studies on the biochemical pathways that support these critical processes, necessitating the high-resolution global metabolomics approach described here to uncover the metabolic interactions between parasite and host RBC. Our results reveal an extensive parasite-mediated modulation of RBC metabolite levels of all classes, including lipids, amino acids, carbohydrates, and nucleotides, with numerous metabolic species varying in proportion to the level of infection. Many of these molecules are scavenged from the host RBCs. This is in accord with the needs of a rapidly proliferating parasite with limited biosynthetic capabilities. Probing these pathways in depth, we used growth inhibition assays to quantitate parasite susceptibility to drugs targeting these pathways and stimulated emission depletion (STED) microscopy to obtain high-resolution images of drug-treated parasites to correlate changes in morphology with specific metabolic blocks in order to validate the data generated by the untargeted metabolomics platform. Thus, interruption of cholesterol scavenging from the host cell led to premature parasite egress, while chemical targeting of the hydrolysis of acyl glycerides led to the buildup of malformed parasites that could not successfully egress. This is the first report detailing the global metabolomic profile of the B. divergens-infected RBC. Besides deciphering diverse aspects of the host-parasite relationship, our results can be exploited by others to uncover further drug targets in the host-parasite biochemical network. IMPORTANCE Human babesiosis is caused by apicomplexan parasites of the Babesia genus and is associated with transfusion-transmitted illness and relapsing disease in immunosuppressed populations. Through its continuous cycles of invasion, proliferation, and egress, B. divergens radically changes the metabolic environment of the host red blood cell, allowing us opportunities to study potential chemical vulnerabilities that can be targeted by drugs. This is the first global metabolomic profiling of Babesia-infected human red blood cells, and our analysis revealed perturbation in all biomolecular classes at levels proportional to the level of infection. In particular, lipids and energy flux pathways in the host cell were altered by infection. We validated the changes in key metabolic pathways by performing inhibition assays accompanied by high-resolution microscopy. Overall, this global metabolomics analysis of Babesia-infected red blood cells has helped to uncover novel aspects of parasite biology and identified potential biochemical pathways that can be targeted for chemotherapeutic intervention.

Tick-Borne Pathogens Associated with Medically Important Ticks in Alabama: A Four-Year Survey

Background: Tick-borne diseases (TBDs) represent a significant threat to human health in the United States. Based on reported cases of notifiable TBDs to the Centers for Disease Control and Prevention (CDC) the state of Alabama is no exception, yet previously there has been no active surveillance program in place to comprehensively assess the presence and prevalence of tick vectors and their associated TBD pathogens in Alabama. Here we summarize initial findings from a 4-year survey to address this unmet need. Materials and Methods: Beginning in 2018 and proceeding through 2021, ticks were collected throughout the state of Alabama and pooled before being screened for a panel of TBD pathogens known to circulate in the United States. Results: Consistent with previously reported cases, TBD pathogens associated with anaplasmosis, babesiosis, ehrlichiosis, and spotted fever rickettsiosis were detected in ticks of Alabama. Causative agents for tularemia and Lyme disease were not detected despite previously reported human disease cases. There was also no evidence of Heartland virus despite recent reports of the virus being detected in ticks in Northwestern counties. Conclusions: While these results serve to provide some insights into TBD pathogens associated with ticks in Alabama, they also raise many questions that highlight the need for additional studies and continued surveillance to fully understand the TBD threat to human health in Alabama.

Ring stage classification of Babesia microti and Plasmodium falciparum using optical diffraction 3D tomographic technique

Background

Babesia is an intraerythrocytic parasite often misdiagnosed as a malaria parasite, leading to inappropriate treatment of the disease especially in co-endemic areas. In recent years, optical diffraction tomography (ODT) has shown great potential in the field of pathogen detection by quantification of three-dimensional (3D) imaging tomograms. The 3D imaging of biological cells is crucial to investigate and provide valuable information about the mechanisms behind the pathophysiology of cells and tissues.

Methods

The early ring stage of P. falciparum were obtained from stored stock of infected RBCs and of B. microti were obtained from infected patients during diagnosis. The ODT technique was applied to analyze and characterize detailed differences between P. falciparum and B. microti ring stage at the single cell level. Based on 3D quantitative information, accurate measurement was performed of morphological, biochemical, and biophysical parameters.

Results

Accurate measurements of morphological parameters indicated that the host cell surface area at the ring stage in B. microti was significantly smaller (140.2 ± 17.1 µm2) than that in P. falciparum (159.0 ± 15.2 µm2), and sphericities showed higher levels in B. microti-parasitized cells (0.66 ± 0.05) than in P. falciparum (0.60 ± 0.04). Based on biochemical parameters, host cell hemoglobin level was significantly higher and membrane fluctuations were respectively more active in P. falciparum-infected cells (30.25 ± 2.96 pg; 141.3 ± 24.68 nm) than in B. microti (27.28 ± 3.52 pg; 110.1 ± 38.83 nm). The result indicates that P. falciparum more actively altered host RBCs than B. microti.

Conclusion

Although P. falciparum and B. microti often show confusable characteristics under the microscope, and the actual three-dimensional properties are different. These differences could be used in differential clinical diagnosis of erythrocytes infected with B. microti and P. falciparum.

Graphical Abstract

Identification and characterization of extracellular vesicles from red cells infected with Babesia divergens and Babesia microti

Babesiosis is a zoonosis and an important blood-borne human parasitic infection that has gained attention because of its growing infection rate in humans by transfer from animal reservoirs. Babesia represents a potential threat to the blood supply because asymptomatic infections in man are common, and blood from such donors can cause severe disease in certain recipients. Extracellular vesicles (EVs) are vesicles released by cells that contain a complex mixture of proteins, lipids, glycans, and genetic information that have been shown to play important roles in disease pathogenesis and susceptibility, as well as cell–cell communication and immune responses. In this article, we report on the identification and characterization of EVs released from red blood cells (RBCs) infected by two major human Babesia species—Babesia divergens from in vitro culture and those from an in vivo B. microti mouse infection. Using nanoparticle tracking analysis, we show that there is a range of vesicle sizes from 30 to 1,000 nm, emanating from the Babesia-infected RBC. The study of these EVs in the context of hemoparasite infection is complicated by the fact that both the parasite and the host RBC make and release vesicles into the extracellular environment. However, the EV frequency is 2- to 10-fold higher in Babesia-infected RBCs than uninfected RBCs, depending on levels of parasitemia. Using parasite-specific markers, we were able to show that ~50%–60% of all EVs contained parasite-specific markers on their surface and thus may represent the specific proportion of EVs released by infected RBCs within the EV population. Western blot analysis on purified EVs from both in vivo and in vitro infections revealed several parasite proteins that were targets of the host immune response. In addition, microRNA analysis showed that infected RBC EVs have different microRNA signature from uninfected RBC EVs, indicating a potential role as disease biomarkers. Finally, EVs were internalized by other RBCs in culture, implicating a potential role for these vesicles in cellular communication. Overall, our study points to the multiple functional implications of EVs in Babesia–host interactions and support the potential that EVs have as agents in disease pathogenesis.

Elucidating parasite and host-cell factors enabling Babesia infection in sickle red cells under hypoxic/hyperoxic conditions

Sickle red blood cells (RBCs) represent a naturally existing host-cell resistance mechanism to hemoparasite infections. We investigate the basis of this resistance using Babesia divergens grown in sickle (SS) and sickle trait (AS) cells. We found that oxygenation and its corresponding effect on RBC sickling, frequency of fetal hemoglobin positive (HbF+) cells, cellular redox environment, and parasite proliferation dynamics, all played a role in supporting or inhibiting Babesia proliferation. To identify cellular determinants that supported infection, an image flow cytometric tool was developed that could identify sickled cells and constituent Hb. We showed that hypoxic conditions impaired parasite growth in both SS and AS cells. Furthermore, cell sickling was alleviated by oxygenation (hyperoxic conditions), which decreased inhibition of parasite proliferation in SS cells. Interestingly, our tool identified HbF+-SS as host-cells of choice under both hypoxic and hyperoxic conditions, which was confirmed using cord RBCs containing high amounts of HbF+ cells. Uninfected SS cells showed a higher reactive oxygen species-containing environment, than AA or AS cells, which was further perturbed on infection. In hostile SS cells we found that Babesia alters its subpopulation structure, with 1N dominance under hypoxic conditions yielding to equivalent ratios of all parasite forms at hyperoxic conditions, favorable for growth. Multiple factors, including oxygenation and its impact on cell shape, HbF positivity, redox status, and parasite pleiotropy allow Babesia propagation in sickle RBCs. Our studies provide a cellular and molecular basis of natural resistance to Babesia, which will aid in defining novel therapies against human babesiosis.

Comparative genomic analysis of Babesia duncani responsible for human babesiosis

Background

Human babesiosis, caused by parasites of the genus Babesia, is an emerging and re-emerging tick-borne disease that is mainly transmitted by tick bites and infected blood transfusion. Babesia duncani has caused majority of human babesiosis in Canada; however, limited data are available to correlate its genomic information and biological features.

Results

We generated a B. duncani reference genome using Oxford Nanopore Technology (ONT) and Illumina sequencing technology and uncovered its biological features and phylogenetic relationship with other Apicomplexa parasites. Phylogenetic analyses revealed that B. duncani form a clade distinct from B. microti, Babesia spp. infective to bovine and ovine species, and Theileria spp. infective to bovines. We identified the largest species-specific gene family that could be applied as diagnostic markers for this pathogen. In addition, two gene families show signals of significant expansion and several genes that present signatures of positive selection in B. duncani, suggesting their possible roles in the capability of this parasite to infect humans or tick vectors.

Conclusions

Using ONT sequencing and Illumina sequencing technologies, we provide the first B. duncani reference genome and confirm that B. duncani forms a phylogenetically distinct clade from other Piroplasm parasites. Comparative genomic analyses show that two gene families are significantly expanded in B. duncani and may play important roles in host cell invasion and virulence of B. duncani. Our study provides basic information for further exploring B. duncani features, such as host-parasite and tick-parasite interactions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12915-022-01361-9.

Fluorescence In Situ Hybridization (FISH) Tests for Identifying Protozoan and Bacterial Pathogens in Infectious Diseases

Diagnosing and treating many infectious diseases depends on correctly identifying the causative pathogen. Characterization of pathogen-specific nucleic acid sequences by PCR is the most sensitive and specific method available for this purpose, although it is restricted to laboratories that have the necessary infrastructure and finance. Microscopy, rapid immunochromatographic tests for antigens, and immunoassays for detecting pathogen-specific antibodies are alternative and useful diagnostic methods with different advantages and disadvantages. Detection of ribosomal RNA molecules in the cytoplasm of bacterial and protozoan pathogens by fluorescence in-situ hybridization (FISH) using sequence-specific fluorescently labelled DNA probes, is cheaper than PCR and requires minimal equipment and infrastructure. A LED light source attached to most laboratory light microscopes can be used in place of a fluorescence microscope with a UV lamp for FISH. A FISH test hybridization can be completed in 30 min at 37 °C and the whole test in less than two hours. FISH tests can therefore be rapidly performed in both well-equipped and poorly-resourced laboratories. Highly sensitive and specific FISH tests for identifying many bacterial and protozoan pathogens that cause disease in humans, livestock and pets are reviewed, with particular reference to parasites causing malaria and babesiosis, and mycobacteria responsible for tuberculosis.

Case Report: A Fatal Case of Babesiosis in a Splenectomized Male Patient from Western India

Human babesiosis is a rare disease, caused by Babesia species and commonly transmitted by tick bite. Although human babesiosis is known to be asymptomatic in immunocompetent hosts, clinical cases of severe babesiosis have been reported from splenectomized or immunocompromised individuals. To our knowledge, only one case of human babesiosis in India has been previously reported. Here, we report a case of severe babesiosis with high parasitemia (∼70%) in a 30-year-old asplenic farmer. The patient presented with fever, yellowish discoloration of skin, oliguria, and anemia; he eventually developed multiorgan failure syndrome and died. Peripheral blood films were prepared and used to confirm the presence of piroplasms by microscopy. Total DNA isolated from blood was used for 18S ribosomal RNA gene fragment amplification by polymerase chain reaction, which was subject to Sanger sequencing. Although 18S sequence indicated that the Babesia species infecting the patient was similar to that of other Babesia species originating from wild mammals, species identification could not be done. Phylogenetic analysis revealed that the patient-derived pathogen is distinct because it forms a separate clade in the cladogram.

Identification of Babesia capreoli from Korean Water Deer in the Republic of Korea

Babesiosis is a tick-borne disease caused by intraerythrocytic protozoa belonging to the genus Babesia that is primarily transmitted through Ixodid ticks and is highly pathogenic to ruminants, horses, pigs, dogs, cats, and in some cases, even humans. Babesia is considered an increasing threat to animal and human health. In this study we report Babesia capreoli infection in Korean water deer (Hydropotes inermis argyropus). Blood samples of 77 wild animals (62 Korean water deer and 15 Korean raccoon dogs [Nyctereutes procyonoides koreensis]) were analyzed to detect Babesia infection. First, PCR was performed to investigate Babesia infection using the partial 18S rRNA gene. Among the 77 wild animals examined, 11 Korean water deer were positive for infection as per the results of sequence analysis. Next, these 11 samples were reanalyzed by PCR using newly designed primers to differentiate between B. capreoli and Babesia divergens. Finally, only one Korean water deer sample was found to be positive for B. capreoli. The nucleotide sequence of this protozoan showed 99.6 - 99.7% identity to those of B. capreoli reported previously. Phylogenetic analysis revealed that the sequence belonged to the B. capreoli clade and diverged from the B. divergens clade. Three nucleotides at positions 631, 663, and 1637 were analyzed to differentiate between B. capreoli and B. divergens. The nucleotides at positions 631 and 1637 were identical to those of B. capreoli, whereas that at position 663 was different. The sequence detected in Korean water deer also exhibited differences at other four positions (669, 704, 711, and 1661) compared with other B. capreoli sequences. This study indicates that Korean water deer serve as a reservoir for B. capreoli. In addition, the primers designed in this study can be used to detect B. capreoli. Future studies should explore the tick vectors that transmit B. capreoli and its pathogenicity. This study was approved by the Institutional Committee of Graduate Studies and Research at Jeonbuk National University, ROK (IACUC decision no.: CBU 2014-00026).

Prevalence of camel babesiosis in southeast of Iran

Babesiosis is a globally distributed zoonotic parasitic disease in a broad range of vertebrates with great importance in the veterinary field. The standard diagnostic test for Babesiosis in animals is microscopic identification of the parasite in a venous blood smear stained with Giemsa combined with assessment of clinical manifestations throughout the acute phase of the disease. The present study was planned to determine the presence of Babesia species in camels from the southeastern regions of Iran. A total of 140 blood samples of camels were randomly collected in four selected cities including Qaen, Nehbandan, Iranshahr, and Zahedan from March to August 2019. Blood smears of each case were also examined by the Giemsa staining method and extracted DNA samples were subjected to internal transcribed spacers (ITS1) polymerase chain reaction (PCR) amplification. The prevalence rates using microscopically and molecular examinations were 10% and 19.28%, respectively. The prevalence rates significantly vary between the selected regions (p = 0.003). PCR technique showed higher sensitivity than microscopy. We found that all infected camels were positive for Babesia caballi. The rate of infection with Babesia among the camel in Zahedan is remarkable. Early diagnosis and early treatment can prevent further spread of the disease in this area.

An annotated checklist of the eukaryotic parasites of humans, exclusive of fungi and algae

The classification of "parasites" in the medical field is a challenging notion, a group which historically has included all eukaryotes exclusive of fungi that invade and derive resources from the human host. Since antiquity, humans have been identifying and documenting parasitic infections, and this collective catalog of parasitic agents has expanded considerably with technology. As our understanding of species boundaries and the use of molecular tools has evolved, so has our concept of the taxonomy of human parasites. Consequently, new species have been recognized while others have been relegated to synonyms. On the other hand, the decline of expertise in classical parasitology and limited curricula have led to a loss of awareness of many rarely encountered species. Here, we provide a comprehensive checklist of all reported eukaryotic organisms (excluding fungi and allied taxa) parasitizing humans resulting in 274 genus-group taxa and 848 species-group taxa. For each species, or genus where indicated, a concise summary of geographic distribution, natural hosts, route of transmission and site within human host, and vectored pathogens are presented. Ubiquitous, human-adapted species as well as very rare, incidental zoonotic organisms are discussed in this annotated checklist. We also provide a list of 79 excluded genera and species that have been previously reported as human parasites but are not believed to be true human parasites or represent misidentifications or taxonomic changes.

Sickle Cell Anemia and Babesia Infection

Babesia is an intraerythrocytic, obligate Apicomplexan parasite that has, in the last century, been implicated in human infections via zoonosis and is now widespread, especially in parts of the USA and Europe. It is naturally transmitted by the bite of a tick, but transfused blood from infected donors has also proven to be a major source of transmission. When infected, most humans are clinically asymptomatic, but the parasite can prove to be lethal when it infects immunocompromised individuals. Hemolysis and anemia are two common symptoms that accompany many infectious diseases, and this is particularly true of parasitic diseases that target red cells. Clinically, this becomes an acute problem for subjects who are prone to hemolysis and depend on frequent transfusions, like patients with sickle cell anemia or thalassemia. Little is known about Babesia's pathogenesis in these hemoglobinopathies, and most parallels are drawn from its evolutionarily related Plasmodium parasite which shares the same environmental niche, the RBCs, in the human host. In vitro as well as in vivo Babesia-infected mouse sickle cell disease (SCD) models support the inhibition of intra-erythrocytic parasite proliferation, but mechanisms driving the protection of such hemoglobinopathies against infection are not fully studied. This review provides an overview of our current knowledge of Babesia infection and hemoglobinopathies, focusing on possible mechanisms behind this parasite resistance and the clinical repercussions faced by Babesia-infected human hosts harboring mutations in their globin gene.

Detection of Anaplasma phagocytophilum, Babesia odocoilei, Babesia sp., Borrelia burgdorferi Sensu Lato, and Hepatozoon canis in Ixodes scapularis Ticks Collected in Eastern Canada

Tick-borne pathogens cause infectious diseases that inflict much societal and financial hardship worldwide. Blacklegged ticks, Ixodes scapularis, are primary vectors of several epizootic and zoonotic pathogens. The aim was to find varius pathogens of I. scapularis and to determine their prevalence. In Ontario and Quebec, 113 I. scapularis ticks were collected from songbirds, mammals, including humans, and by flagging. PCR and DNA sequencing detected five different microorganisms: Anaplasma phagocytophilum, 1 (0.9%); Babesia odocoilei, 17 (15.3%); Babesia microti-like sp., 1 (0.9%); Borrelia burgdorferi sensu lato (Bbsl), 29 (26.1%); and Hepatozoon canis, 1 (0.9%). Five coinfections of Bbsl and Babesia odocoilei occurred. Notably, H. canis was documented for the first time in Canada and, at the same time, demonstrates the first transstadial passage of H. canis in I. scapularis. Transstadial passage of Bbsl and B. odocoilei was also witnessed. A novel undescribed piroplasm (Babesia microti-like) was detected. An established population of I. scapularis ticks was detected at Ste-Anne-de-Bellevue, Quebec. Because songbirds widely disperse I. scapularis larvae and nymphs, exposure in an endemic area is not required to contract tick-borne zoonoses. Based on the diversity of zoonotic pathogens in I. scapularis ticks, clinicians need to be aware that people who are bitten by I. scapularis ticks may require select antimicrobial regimens.

The Tick Microbiota Dysbiosis Promote Tick-Borne Pathogen Transstadial Transmission in a Babesia microti-Infected Mouse Model

Ticks are obligate hematophagous ectoparasites. They are important vectors for many pathogens, of both medical and veterinary importance. Antibiotic residues in animal food are known, but very little is known about the effects of antibiotic residues in animals on the microbiome diversity of ticks and tick-borne pathogen transmission. We used a Haemaphysalis longicornis–infested mouse model to evaluate the effect of antibiotic usage on tick microbiome. Nymphal ticks were fed on an antibiotic cocktail-treated or water control mice. Adult ticks molted from nymphs fed on the antibiotic cocktail-treated mouse had a dysbiosed microbiota. Nymphal ticks were also fed on a B. microti–infected mice that had been treated with antibiotic cocktail or water. We found that the B. microti infection in adult ticks with a dysbiosed microbiota (44.7%) was increased compared with the control adult ticks (24.2%) by using qPCR targeting 18S rRNA gene. This may increase the risk of tick-borne pathogens (TBPs) transmission from adult ticks to a vertebrate host. These results show that an antibiotic-treated mouse can induce tick microbiota dysbiosis. Antibiotic treatment of B. microti-infected mouse poses the possibility of increasing transstadial transmission of B. microti from the nymph to the adult H. longicornis. These findings suggest that B. microti transmission may be exacerbated in high antibiotic usage areas.

The New Status of Parasitic Diseases in the COVID-19 Pandemic-Risk Factors or Protective Agents?

It is possible that parasites may influence the course of COVID-19 infection, as either risk factors or protective agents; as such, the current coronavirus pandemic may affect the diagnosis and prevention of parasitic disease, and its elimination programs. The present review highlights the similarity between the symptoms of human parasitoses and those of COVID-19 and discuss their mutual influence. The study evaluated selected human parasitoses with similar symptoms to COVID-19 and examined their potential influence on SARS-CoV-2 virus invasion. The available data suggest that at least several human parasitoses could result in misdiagnosis of COVID-19. Some disorders, such as malaria, schistosomiasis and soil-transmitted helminths, can increase the risk of severe infection with COVID-19. It is also suggested that recovery from parasitic disease can enhance the immune system and protect from COVID-19 infection. In addition, the COVID-19 pandemic has affected parasitic disease elimination programs in endemic regions and influenced the number of diagnoses of human parasitoses.

Detection of Babesia odocoilei in Humans with Babesiosis Symptoms

Human babesiosis is a life-threatening infectious disease that causes societal and economic impact worldwide. Several species of Babesia cause babesiosis in terrestrial vertebrates, including humans. A one-day clinic was held in Ontario, Canada, to see if a red blood cell parasite, which is present in blacklegged ticks, Ixodes scapularis, is present in humans. Based on PCR testing and DNA sequencing of the 18S rRNA gene, we unveiled B. odocoilei in two of 19 participants. DNA amplicons from these two patients are almost identical matches with the type strains of B. odocoilei in GenBank. In addition, the same two human subjects had the hallmark symptoms of human babesiosis, including night sweats, chills, fevers, and profound fatigue. Based on symptoms and molecular identification, we provide substantive evidence that B. odocoilei is pathogenic to humans. Dataset reveals that B. odocoilei serologically cross-reacts with Babesia duncani. Clinicians must realize that there are more than two Babesia spp. in North America that cause human babesiosis. This discovery signifies the first report of B. odocoilei causing human babesiosis.

Detection of Babesia odocoilei in Ixodes scapularis Ticks Collected in Southern Ontario, Canada

Tick-borne zoonotic diseases have an economic and societal impact on the well-being of people worldwide. In the present study, a high frequency of Babesia odocoilei, a red blood cell parasite, was observed in the Huronia area of Ontario, Canada. Notably, 71% (15/21) blacklegged ticks, Ixodes scapularis, collected from canine and feline hosts were infected with B. odocoilei. Consistent with U.S. studies, 12.5% (4/32) of questing I. scapularis adults collected by flagging in various parts of southwestern Ontario were positive for B. odocoilei. Our data show that all B. odocoilei strains in the present study have consistent genetic identity, and match type strains in the GenBank database. The high incidence of B. odocoilei in the Huronia area indicates that this babesial infection is established, and is cycling enzootically in the natural environment. Our data confirm that B. odocoilei has wide distribution in southern Ontario.

Likely Geographic Distributional Shifts among Medically Important Tick Species and Tick-Associated Diseases under Climate Change in North America: A Review

Ticks rank high among arthropod vectors in terms of numbers of infectious agents that they transmit to humans, including Lyme disease, Rocky Mountain spotted fever, Colorado tick fever, human monocytic ehrlichiosis, tularemia, and human granulocytic anaplasmosis. Increasing temperature is suspected to affect tick biting rates and pathogen developmental rates, thereby potentially increasing risk for disease incidence. Tick distributions respond to climate change, but how their geographic ranges will shift in future decades and how those shifts may translate into changes in disease incidence remain unclear. In this study, we have assembled correlative ecological niche models for eight tick species of medical or veterinary importance in North America (Ixodes scapularis, I. pacificus, I. cookei, Dermacentor variabilis, D. andersoni, Amblyomma americanum, A. maculatum, and Rhipicephalus sanguineus), assessing the distributional potential of each under both present and future climatic conditions. Our goal was to assess whether and how species' distributions will likely shift in coming decades in response to climate change. We interpret these patterns in terms of likely implications for tick-associated diseases in North America.

Emerging Human Babesiosis with "Ground Zero" in North America

The first case of human babesiosis was reported in the literature in 1957. The clinical disease has sporadically occurred as rare case reports in North America and Europe in the subsequent decades. Since the new millennium, especially in the last decade, many more cases have apparently appeared not only in these regions but also in Asia, South America, and Africa. More than 20,000 cases of human babesiosis have been reported in North America alone. In several cross-sectional surveys, exposure to Babesia spp. has been demonstrated within urban and rural human populations with clinical babesiosis reported in both immunocompromised and immunocompetent humans. This review serves to highlight the widespread distribution of these tick-borne pathogens in humans, their tick vectors in readily accessible environments such as parks and recreational areas, and their phylogenetic relationships.

Tick-borne zoonoses and commonly used diagnostic methods in human and veterinary medicine

Around the world, human health and animal health are closely linked in terms of the One Health concept by ticks acting as vectors for zoonotic pathogens. Animals do not only maintain tick cycles but can either be clinically affected by the same tick-borne pathogens as humans and/or play a role as reservoirs or sentinel pathogen hosts. However, the relevance of different tick-borne diseases (TBDs) may vary in human vs. veterinary medicine, which is consequently reflected by the availability of human vs. veterinary diagnostic tests. Yet, as TBDs gain importance in both fields and rare zoonotic pathogens, such as Babesia spp., are increasingly identified as causes of human disease, a One Health approach regarding development of new diagnostic tools may lead to synergistic benefits. This review gives an overview on zoonotic protozoan, bacterial and viral tick-borne pathogens worldwide, discusses commonly used diagnostic techniques for TBDs, and compares commercial availability of diagnostic tests for humans vs. domestic animals, using Germany as an example, with the aim of highlighting existing gaps and opportunities for collaboration in a One Health framework.

Genomic Profiling for Piroplasms in Feeding Ixodid Ticks in the Eastern Cape, South Africa

Importation of tick-infected animals and the uncontrollable migration of birds and wild animals across borders can lead to geographical expansion and redistribution of ticks and pathogen vectors, thus leading to the emergence and re-emergence of tick-borne diseases in humans and animals. Comparatively, little is known about the occurrence of piroplasms in ixodid ticks in the Eastern Cape, South Africa, thus necessitating this study, which is aimed at detecting piroplasms (Theileria and Babesia) from feeding tick samples collected from cattle, sheep, and goats in selected sites in the Eastern Cape, South Africa. A total of 1200 feeding ixodid ticks collected from farm animals at selected homesteads were first subjected to molecular identification using mitochondrial 12S ribosomal RNA (rRNA) gene by PCR and were further tested for the presence of piroplasms through amplification of the 18S rRNA gene via nested-PCR followed by sequencing of the PCR products. The results indicated that 853 (71.1%) corresponded to the genus Rhipicephalus, 335 (27.9%) corresponded to genus Amblyomma, and 12 (1%) corresponded to genus Haemaphysalis. Amblyomma hebraeum and Rhipicephalus appendiculatus were the most common identified ticks from this study. The 18S rRNA nested-PCR revealed that 44 (3.7%) samples were confirmed positive for Theileria. A homology search for the generated sequences revealed a high percentage identity of 98–98.9% similarity to T. buffeli, T. orientalis, and T. sergenti in the GenBank. Based on the results obtained herein, we conclude that there is a big diversity of Theileria species; therefore, we suggest that this research should cover more geographical areas in order to reveal the true prevalence of this pathogen in the studied area because this will be a great step in the possible prevention of an outbreak that could have devastating effects on livestock production and human health in both the studied areas and South Africa at large.

The first human case of babesiosis mimicking Reiter's syndrome

Babesiosis is a tick-borne disease that may exhibit a broad range of clinical manifestations. According to the Food and Drug Administration (FDA), Babesia species belong to the most common transfusion-transmitted pathogens (FDA, May 2019), but the awareness of the disease caused by these parasitic protists is still low. In immunocompromised patients, the clinical course of babesiosis may be of extreme severity and may require hospital admission. We demonstrate a case of a young male who experienced severe polytrauma requiring repetitive blood transfusions. Six months later, the patient developed a classic triad of arthritis, conjunctivitis and non-specific urethritis. These symptoms largely mimicked Reiter's syndrome. The patient was later extensively examined by an immunologist, rheumatologist, urologist, and ophthalmologist with no additional medical findings. In the search for the cause of his symptoms, a wide laboratory testing for multiple human pathogens was performed and revealed a babesiosis infection. This was the first case of human babesiosis mimicking Reiter's syndrome. Following proper antimicrobial therapy, the patient fully recovered in four weeks. We aim to highlight that a search for Babesia species should be considered in patients with non-specific symptomatology and a history of blood transfusion or a possible tick exposure in pertinent endemic areas.

Combined Immunofluorescence (IFA) and Fluorescence In Situ Hybridization (FISH) Assays for Diagnosing Babesiosis in Patients from the USA, Europe and Australia

Apicomplexan parasites of the genus Babesia cause babesiosis in humans and animals worldwide. Human babesiosis is a predominantly zoonotic disease transmitted by hard ticks that is of increasing health concern in the USA and many other countries. Microscopic examination of stained blood smears, detection of serum antibodies by immunoassays and identification of parasite nucleic acid in blood by qPCR and fluorescence in situ hybridization (FISH) are some methods available for diagnosing babesiosis. This study investigated the use of a Babesia genus-specific FISH test for detecting Babesia parasites in blood smears and immunofluorescence assay (IFA) for detecting serum antibodies to Babesia duncani and Babesia microti, two common species that cause human babesiosis in the USA. The findings with clinical samples originating from USA, Australia, Europe and elsewhere demonstrate that the parallel use of Babesia genus-specific FISH and IFA tests for B. duncani and B. microti provides more useful diagnostic information in babesiosis and that B. duncani infections are more widespread globally than presently recognized.

Detection of Babesia odocoilei in Ixodes scapularis Ticks Collected from Songbirds in Ontario and Quebec, Canada

Songbirds widely disperse ticks that carry a diversity of pathogens, some of which are pathogenic to humans. Among ticks commonly removed from songbirds, the blacklegged tick, Ixodes scapularis, can harbor any combination of nine zoonotic pathogens, including Babesia species. From May through September 2019, a total 157 ticks were collected from 93 songbirds of 29 species in the Canadian provinces of Ontario and Québec. PCR testing for the 18S gene of Babesia species detected Babesia odocoilei in 12.63% of I. scapularis nymphs parasitizing songbirds in Ontario and Québec; none of the relatively small numbers of Ixodes muris, Ixodes brunneus, or Haemaphysalis leporispalustris were PCR-positive. For ticks at each site, the prevalence of B. odocoilei was 16.67% in Ontario and 8.89% and 5.26% in Québec. Of 31 live, engorged I. scapularis larvae and nymphs held to molt, 25 ticks completed the molt; five of these molted ticks were positive for B. odocoilei. PCR-positive ticks were collected from six bird species—namely, Common Yellowthroat, Swainson’s Thrush, Veery, House Wren, Baltimore Oriole, and American Robin. Phylogenetic analysis documented the close relationship of B. odocoilei to Babesia canis canis and Babesia divergens, the latter a known pathogen to humans. For the first time in Canada, we confirm the transstadial passage of B. odocoilei in I. scapularis molting from larvae to nymphs. A novel host record reveals I. scapularis on a Palm Warbler. Our findings show that B. odocoilei is present in all mobile life stages of I. scapularis, and it is widely dispersed by songbirds in Ontario and Québec.

Transfusion-associated babesiosis in China: A case report

Babesiosis, a novel zoonosis, is endemic in the Northeast and Midwest United States. This disease is primarily transmitted by ticks and less commonly transmitted through blood transfusion. Here, we present a case of human babesiosis of unknown etiology. The patient may have been infected through blood transfusion. This patient had fever for more than 1 month, accompanied by fatigue, anemia, jaundice, and other symptoms. Clinical improvement was unsatisfactory with antibiotics. Subsequently, peripheral blood smears showed many circulating forms of parasites,morphologically consistent with Babesia in red blood cells. Gene sequencing suggested Babesia microti. We treated the patient with azithromycin combined with other symptomatic supportive treatment. Finally, the patient recovered and was discharged. The intensity of babesiosis ranges from mild to severe and can be fatal, so early diagnosis and treatment are warranted.

Educational Case: Babesiosis and Transfusion-Transmitted Infections

The following fictional case is intended as a learning tool within the Pathology Competencies for Medical Education (PCME), a set of national standards for teaching pathology. These are divided into three basic competencies: Disease Mechanisms and Processes, Organ System Pathology, and Diagnostic Medicine and Therapeutic Pathology. For additional information, and a full list of learning objectives for all three competencies, seehttp://journals.sagepub.com/doi/10.1177/2374289517715040.¹

A Fluorescence in Situ Hybridization (FISH) Test for Diagnosing Babesiosis

Apicomplexan parasites of the genus Babesia cause babesiosis in humans and animals. The microscopic examination of stained blood smears, detection of serum antibodies by immunoassays, and PCR-based identification of parasite nucleic acid in blood are common laboratory methods for diagnosing babesiosis. The present study evaluated a commercially available Babesia genus-specific fluorescence in situ hybridization (FISH) test for detecting Babesia parasites in blood smears. The FISH test detected Babesia duncani and Babesia microti, two common species that cause human infections in the USA, and other Babesia species of human and veterinary importance in less than two hours. The Babesia genus-specific FISH test supplements other existing laboratory methods for diagnosing babesiosis and may be particularly useful in resource-limited laboratories.

Imported Human Babesiosis, Singapore, 2018

In 2018, Babesia microti infection was diagnosed for a 37-year-old man in Singapore who acquired the infection in the United States. This case highlights the recent rise of tickborne infections in the United States and the risk for their spread, because of increasing global interconnectivity, to regions where they are not endemic.

Detection of Rare Objects by Flow Cytometry: Imaging, Cell Sorting, and Deep Learning Approaches

Flow cytometry nowadays is among the main working instruments in modern biology paving the way for clinics to provide early, quick, and reliable diagnostics of many blood-related diseases. The major problem for clinical applications is the detection of rare pathogenic objects in patient blood. These objects can be circulating tumor cells, very rare during the early stages of cancer development, various microorganisms and parasites in the blood during acute blood infections. All of these rare diagnostic objects can be detected and identified very rapidly to save a patient's life. This review outlines the main techniques of visualization of rare objects in the blood flow, methods for extraction of such objects from the blood flow for further investigations and new approaches to identify the objects automatically with the modern deep learning methods.

Blood parasites (Babesia, Hepatozoon and Trypanosoma) of rodents, Lithuania: part I. Molecular and traditional microscopy approach

Wild rodents, as natural reservoir hosts carrying various species of pathogens, play an important role in the evolution and emergence of zoonotic diseases. In this study, protist parasites, namely Babesia sp., Trypanosoma sp. and Hepatozoon sp. were studied in rodent populations in Lithuania. Two hundred forty rodent specimens of seven species were analysed by a combined approach using polymerase chain reaction (PCR)-based techniques and traditional microscopic examination. The total prevalence of blood parasites reached 35% in rodent communities. The prevalence of Hepatozoon sp. reached the highest value (32%), followed by Trypanosoma sp. (5%) and Babesia sp. (3%). Myodes glareolus and Microtus agrestis were the most heavily infected rodent species. Comparison of microscopy and PCR-based methods showed that the two approaches might give different results and thus can lead to an underestimation of the actual prevalence and abundance of parasites. In our study, PCR-based assays were more sensitive and robust than traditional microscopy. However, precise molecular results for the estimation of the prevalence of Babesia sp. and Hepatozoon sp. were achieved only by using several sets of primers. To avoid inaccurate results, the improvement and detailed description of molecular and microscopy protocols are required.

Zoonotic Babesia: A scoping review of the global evidence

BACKGROUND

Babesiosis is a parasitic vector-borne disease of increasing public health importance. Since the first human case was reported in 1957, zoonotic species have been reported on nearly every continent. Zoonotic Babesia is vectored by Ixodes ticks and is commonly transmitted in North America by Ixodes scapularis, the tick species responsible for transmitting the pathogens that also cause Lyme disease, Powassan virus, and anaplasmosis in humans. Predicted climate change is expected to impact the spread of vectors, which is likely to affect the distribution of vector-borne diseases including human babesiosis.

METHODS

A scoping review has been executed to characterize the global evidence on zoonotic babesiosis. Articles were compiled through a comprehensive search of relevant bibliographic databases and targeted government websites. Two reviewers screened titles and abstracts for relevance and characterized full-text articles using a relevance screening and data characterization tool developed a priori.

RESULTS

This review included 1394 articles relevant to human babesiosis and/or zoonotic Babesia species. The main zoonotic species were B. microti, B. divergens, B. duncani and B. venatorum. Articles described a variety of study designs used to study babesiosis in humans and/or zoonotic Babesia species in vectors, animal hosts, and in vitro cell cultures. Topics of study included: pathogenesis (680 articles), epidemiology (480), parasite characterization (243), diagnostic test accuracy (98), mitigation (94), treatment (65), transmission (54), surveillance (29), economic analysis (7), and societal knowledge (1). No articles reported predictive models investigating the impact of climate change on Babesia species.

CONCLUSION

Knowledge gaps in the current evidence include research on the economic burden associated with babesiosis, societal knowledge studies, surveillance of Babesia species in vectors and animal hosts, and predictive models on the impact of climate change. The scoping review results describe the current knowledge and knowledge gaps on zoonotic Babesia which can be used to inform future policy and decision making.

Evaluation of a Novel Multiplex High-Definition PCR Assay for Detection of Tick-Borne Pathogens in Whole-Blood Specimens

The prevalence of tick-borne infections has been steadily increasing in both number and geographic distribution in the United States and abroad. This increase, in conjunction with the continued recognition of novel pathogens transmitted by ticks, has made accurate diagnosis of these infections challenging. Mainstay serologic tests are insensitive during the acute phase of infection and are often cross-reactive with similar pathogenic and nonpathogenic organisms. Further, they are unable to reliably differentiate active versus past infection which can lead to misdiagnosis and incorrect understanding of the epidemiology and incidence of specific tick-borne pathogens. We evaluated a novel multiplexed high-definition PCR (HDPCR) Tickborne Panel (TBP) assay (ChromaCode, Carlsbad, CA) for the detection of nine tick-borne pathogens or groups associated with human illness. The HDPCR technology enables multiplex identification of multiple targets in a single fluorometric channel based on fluorescent signal modulation using a limiting probe design. A collection of 530 whole-blood specimens collected from patients being evaluated for tick-borne infections, in addition to a panel of 93 simulated specimens, were used to challenge the HDPCR TBP. The results were compared to a clinically validated traditional multiplexed PCR test with additional sequence analysis and clinical history collected to aid in resolving discrepancies. Among clinical specimens the TBP demonstrated 100% sensitivity for the identification of Anaplasma phagocytophilum, Borrelia miyamotoi, Borrelia mayonii, and Rickettsia rickettsii The sensitivity for identification of B. burgdorferi was 44.4% compared to a composite gold standard. Among simulated specimens containing single or multiple targets present at 10³ to 10⁵ copies/PCR, the sensitivity of TBP was 100% for all targets, with a combined specificity of 99.5%. Of note, an increased rate of false-positive results was observed among simulated specimens that contained multiple targets. Based on these data, we find the HDPCR TBP to be a useful adjunct for the diagnosis of tick-borne infections in patients with suspected tick-borne illness.

Detection and characterization of an emerging type of Babesia sp. similar to Babesia motasi for the first case of human babesiosis and ticks in Korea

Babesiosis is a tick-transmitted intraerythrocytic zoonosis. In Korea, the first mortalities were reported in 2005 due to Babesia sp. detection in sheep; herein we report epidemiological and genetic characteristics of a second case of babesiosis. Microscopic analysis of patient blood revealed polymorphic merozoites. To detect Babesia spp., PCR was performed using Babesia specific primers for β-tubulin, 18S rDNA, COB, and COX3 gene fragments. 18S rDNA analysis for Babesia sp., showed 98% homology with ovine Babesia sp. and with Babesia infections in Korea in 2005. Moreover, phylogenetic analysis of 18S rDNA, COB, and COX3 revealed close associations with B. motasi. For identifying the infectious agent, Haemaphysalis longicornis (296) and Haemaphysalis flava (301) were collected around the previous residence of the babesiosis patient. Babesia genes were identified in three H. longicornis: one sample was identified as B. microti and two samples were 98% homologous to B. motasi. Our study is the first direct confirmation of the infectious agent for human babesiosis. This case most likely resulted from tick bites from ticks near the patient house of the babesiosis patient. H. longicornis has been implicated as a vector of B. microti and other Babesia sp. infections.

Splenic infarction in babesiosis: A rare presentation

Babesiosis is a protozoan parasitic infection transmitted by the Ixodes tick. Splenic infarction is a rare, but potentially life-threatening complication of babesiosis; it is therefore vital that this complication is recognized.

Babesiosis Vaccines: Lessons Learned, Challenges Ahead, and Future Glimpses

The incidence and prevalence of babesiosis in animals and humans is increasing, yet prevention, control, or treatment measures remain limited and ineffective. Despite a growing body of new knowledge of the biology, pathogenicity, and virulence of Babesia parasites, there is still no well-defined, adequately effective and easily deployable vaccine. While numerous published studies suggest that the development of such anti-Babesia vaccines should be feasible, many others identify significant challenges that need to be overcome in order to succeed. Here, we review historic and recent attempts in babesiosis vaccine discovery to avoid past pitfalls, learn new lessons, and provide a roadmap to guide the development of next-generation babesiosis vaccines.

Delayed hypersensitivity reaction to mammalian galactose-α-1,3-galactose (α-Gal) after repeated tick bites in a patient from France

The α-Gal syndrome is a tick-associated and emerging IgE-mediated hypersensitivity reaction directed against the carbohydrate Galα1-3Galβ1-(3)4GlcNAc-R (α-Gal) epitope after red meat intake. Herein, we describe a clinical case of a 44-year-old French patient who suffered from recurrent anaphylactic reactions after mammalian meat consumption for five years before the final diagnosis of the α-Gal syndrome was established in 2018. The patient also reported multiple tick bites prior to symptom onset. This unique type of allergy has increasingly been reported across the world, but it is still unknown in many European countries. Therefore, the present clinical case should increase awareness among primary care practitioners and further improve the early diagnosis of the α-Gal syndrome in affected individuals.

Probable Locally Acquired Babesia divergens-Like Infection in Woman, Michigan, USA

We report an asplenic patient who was infected with Babesia divergens–like/MO-1. The clinical course was complicated by multiorgan failure that required intubation and dialysis. The patient recovered after an exchange transfusion and antimicrobial drug therapy. Physicians should be alert for additional cases, particularly in asplenic persons.