Reginaldo Bastos

• DVM, MS, PhD
• Washington State University

Introduction The recent discovery of Theileria haneyi, a tick-borne hemoparasite that causes mild clinical signs of equine piroplasmosis, has added complexity to the diagnosis of this reportable disease, which is prevalent among equids globally. Knowledge gaps regarding competent tick vectors that can transmit T. haneyi and the recent outbreak of H...

The tick-borne apicomplexan parasite Babesia bovis causes bovine babesiosis which leads to enormous food and economic losses around the world. The existing resources to manage this disease are limited and have pitfalls, therefore, introduction of new strategies is urgently needed. B. bovis reproduces sexually in the midgut of its tick vector. HAP2,...

Babesia ovis, commonly associated with ovine babesiosis, poses a significant threat to sheep health, often resulting in severe clinical manifestations and high mortality rates. However, the impact of B. ovis on goats has remained uncertain, prompting us to investigate its pathogenicity in caprine hosts. Experimental infections using B. ovis-infecte...

Bovine babesiosis caused by the tick-borne apicomplexan parasite Babesia bovis remains a threat for cattle worldwide, and new vaccines are needed. We propose using immune-subdominant (ISD) antigens as alternative vaccine candidates. We first determined that RAP-1 NT and RRA are subdominant antigens using recombinant antigens in ELISAs against sera...

Equine piroplasmosis (EP) is a global tick-borne disease of equids caused by the intraerythrocytic apicomplexan parasites Theileria equi and Babesia caballi, and the more recently discovered Theileria haneyi. These parasites can be transmitted by several tick species, including Dermacentor, Hyalomma, and Rhipicephalus, but iatrogenic and vertical t...

Background Theileria haneyi is one of the three known causative agents of equine piroplasmosis. While imidocarb is generally effective in the clearance of the highly pathogenic Theileria equi, it is ineffective in the treatment of T. haneyi. Moreover, co-infection with T. haneyi has been shown to impede the successful treatment of T. equi. Furtherm...

Babesia ovis, transmitted by Rhipicephalus bursa ticks, is the causative agent of ovine babesiosis, a disease characterized by fever, anemia, hemoglobinuria, and high mortality in sheep. This study investigates whether sheep that survived babesiosis without treatment can serve as a source of infection for B. ovis-free host-seeking R. bursa larvae i...

Introduction Theileria orientalis, an economically significant tick-borne hemoparasite, infects cattle globally. The T. orientalis Ikeda genotype, transmitted by Haemaphysalis longicornis ticks, is associated with clinical manifestations characterized by anemia, abortions, and mortality, although subclinical infections prevail. Despite the common o...

Theileria equi (T. equi) is an apicomplexan parasite that causes severe hemolytic anemia in equids. Presently, there is inadequate knowledge of the immune responses induced by T. equi in equid hosts impeding understanding of the host parasite relationship and development of potent vaccines for control of T. equi infections. The objective of this st...

Background Theileria haneyi (T. haneyi) is one of the three known causative agents of equine piroplasmosis. While imidocarb is generally effective in the clearance of the highly pathogenic Theileria equi (T. equi), it is ineffective in the treatment of T. haneyi. Moreover, co-infection with T. haneyi has been shown to impede the successful treatmen...

Introduction B. bovis is an apicomplexan parasite responsible for bovine babesiosis, a tick-borne disease with a worldwide impact. The disease remains inefficiently controlled, and few effective drugs, including imidocarb dipropionate (ID), are currently available in endemic areas. The objective of this study was to evaluate whether buparvaquone (B...

Introduction Babesia bovis, a tick-borne apicomplexan parasite causing bovine babesiosis, remains a significant threat worldwide, and improved and practical vaccines are needed. Previous studies defined the members of the rhoptry associated protein-1 (RAP-1), and the neutralization-sensitive rhoptry associated protein-1 related antigen (RRA) superf...

B‐cell leukemia is a rare form of hematologic neoplasia in sheep, especially in adult animals. We present a case report of a 5‐year‐old WhiteFace Sheep wether with suspected acute lymphoblastic leukemia. The patient, a second‐generation relative of ewes experimentally inoculated with atypical scrapie, exhibited acute lethargy and loss of appetite....

Babesiosis is an acute and persistent tick-borne disease caused by protozoan parasites of the genus Babesia. These hemoparasites affect vertebrates globally, resulting in symptoms such as high fever, anemia, jaundice, and even death. Advancements in molecular parasitology revealed new Babesia species/genotypes affecting sheep and goats, including B...

The apicomplexan parasite Babesia bovis is responsible for bovine babesiosis, a poorly controlled tick-borne disease of global impact. The widely conserved gametocyte protein HAPLESS2/GCS1 (HAP2) is uniquely expressed on the surface of B. bovis sexual stage parasites and is a candidate for transmission-blocking vaccines (TBV). Here, we tested wheth...

Introduction Live in vivo attenuated Babesia bovis vaccines produced by sequential passages in splenectomized calves have historically been used to control acute bovine babesiosis in endemic areas worldwide. However, several constraints prevent the widespread use of these vaccines, including the need for several splenectomized calves to produce vac...

The apicomplexan tickborne parasites Babesia bovis and B. bigemina are the major causative agents of bovine babesiosis, a disease that negatively affects the cattle industry and food safety around the world. The absence of correlates of protection represents one major impediment for the development of effective and sustainable vaccines against bovi...

Babesia bigemina is a tick-borne apicomplexan hemoprotozoan responsible for bovine babesiosis. The current drugs used for bovine babesiosis treatment have several drawbacks, including toxicity, the lack of effectiveness to clear the parasite, and potential to develop resistance. Identifying compounds that target essential and unique parasite metabo...

Theileria equi is an obligate intracellular protozoan parasite that causes severe hemolytic anemia in most equid species. Similar to other apicomplexan parasites, T. equi contains rhoptries whose contents have been implicated in host cell invasion and formation of the parasitophorous vacuole that is crucial for survival of the species within cells....

Bovine babesiosis, caused by Babesia bovis, is an economically significant tick-borne disease that imposes restrictions to livestock production worldwide. Current methods to control bovine babesiosis have severe limitations and novel approaches, including transmission-blocking vaccines, are needed. Members of the widely conserved CCp family are mul...

Babesia bovis natural field strains are composed of several geno-phenotypically distinct subpopulations. This feature, together with possible epigenetic modifications, may facilitate adaptation to variable environmental conditions. In this study we compare geno-phenotypical features among long-term (more than 12 years) (LTCP) and short-term culture...

Babesiosis is a disease caused by tickborne hemoprotozoan apicomplexan parasites of the genus Babesia that negatively impacts public health and food security worldwide. Development of effective and sustainable vaccines against babesiosis is currently hindered in part by the absence of definitive host correlates of protection. Despite that, studies...

Background Vector-borne diseases pose an increasing threat to global food security. Vaccines, diagnostic tests, and therapeutics are urgently needed for tick-borne diseases that affect livestock. However, the inability to obtain significant quantities of pathogen stages derived from ticks has hindered research. In vitro methods to isolate pathogens...

Babesia, Cytauxzoon and Theileria are tick-borne apicomplexan parasites of the order Piroplasmida, responsible for diseases in humans and animals. Members of the piroplasmid rhoptry-associated protein-1 (pRAP-1) family have a signature cysteine-rich domain and are important for parasite development. We propose that the closely linked B. microti gen...

Babesiosis is a tick-borne disease with global impact caused by parasites of the phylum Apicomplexa, genus Babesia. Typically, acute bovine babesiosis (BB) is characterized by fever, anemia, hemoglobinuria, and high mortality. Surviving animals remain persistently infected and become reservoirs for parasite transmission. Bovids in China can be infe...

Theileria equi is a widely distributed apicomplexan parasite that causes severe hemolytic anemia in equid species. There is currently no effective vaccine for control of the parasite and understanding the mechanism that T. equi utilizes to invade host cells may be crucial for vaccine development. Unlike most apicomplexan species studied to date, th...

Background Babesia bovis reproduces sexually in the gut of its tick vector Rhipicephalus microplus , which involves expression of 6cys A and 6cys B proteins. Members of the widely conserved 6cys superfamily are candidates for transmission blocking vaccines (TBV), but intricacies in the immunogenicity of the 6cys proteins in the related Plasmodium p...

Apicomplexan parasites are responsible for important livestock diseases that affect the production of much needed protein resources, and those transmissible to humans pose a public health risk. Vaccines, recognized as a cost-effective and environmentally friendly method for the prevention of infectious diseases in livestock, can avert losses in foo...

Apicomplexan parasites are responsible for important livestock diseases that affect the production of much needed protein resources, and those transmissible to humans pose a public health risk. Vaccines, recognized as a cost-effective and environmentally friendly method for the prevention of infectious diseases in livestock, can avert losses in foo...

Apicomplexan parasites are responsible for important livestock diseases that affect the production of much needed protein resources, and those transmissible to humans pose a public health risk. Vaccines, recognized as a cost-effective and environmentally friendly method for the prevention of infectious diseases in livestock, can avert losses in foo...

Apicomplexan parasites are responsible for important livestock diseases that affect the production of much needed protein resources, and those transmissible to humans pose a public health risk. Vaccines, recognized as a cost-effective and environmentally friendly method for the prevention of infectious diseases in livestock, can avert losses in foo...

The apicomplexan parasite Theileria haneyi is one of two known causative agents of equine theileriosis. It causes milder clinical disease than its more virulent counterpart, Theileria equi, in experimentally infected horses, and can superinfect T. equi-positive horses. The current equi merozoite antigen 1 (EMA1)-based competitive enzyme-linked immu...

Bovine babesiosis, caused by Babesia bovis and B. bigemina, is a major tick-borne disease of cattle with global economic impact. The disease can be prevented using integrated control measures including attenuated Babesia vaccines, babesicidal drugs, and tick control approaches. Vaccination of cattle with the Rhipicephalus microplus Bm86-based recom...

The apicomplexan parasite Theileria haneyi is one of two known causative agents of equine theileriosis. It causes milder clinical disease than its more virulent counterpart, Theileria equi, in experimentally infected horses, and can superinfect T. equi-positive horses. The current EMA1-based competitive ELISA used in the U.S. to detect equine theil...

Theileria equi ( T. equi ) is a widely distributed apicomplexan parasite that causes severe hemolytic anemia in equid species. There is currently no effective vaccine for control of the parasite and understanding the mechanism that T. equi utilizes to invade host cells may be crucial for vaccine development. Unlike most apicomplexan species studied...

Bovine babesiosis is a global tick-borne disease that causes important cattle losses and has potential zoonotic implications. The impact of bovine babesiosis in Turkey remains poorly characterized, but several Babesia spp., including B. bovis, B. bigemina, and B. divergens, among others and competent tick vectors, except Rhipicephalus microplus, ha...

Background The most common apicomplexan parasites causing bovine babesiosis are Babesia bovis and B. bigemina, while B. caballi and Theileria equi are responsible for equine piroplasmosis. Treatment and control of these diseases are usually achieved using potentially toxic chemotherapeutics, such as imidocarb diproprionate, but drug-resistant paras...

Background: The most common apicomplexan parasites causing bovine babesiosis are Babesia bovis and B. bigemina, while B. caballi and Theileria equi are responsible for equine piroplasmosis. Treatment and control of these diseases are usually achieved using potentially toxic chemotherapeutics, such as imidocarb diproprionate, but drug-resistant para...

Background: The most common apicomplexan parasites causing bovine babesiosis are Babesia bovis and B. bigemina, while B. caballi and Theileria equi are responsible for equine piroplasmosis. Treatment and control of these diseases are usually achieved using potentially toxic chemotherapeutics, such as imidocarb diproprionate, but drug-resistant para...

Background: The most common apicomplexan parasites causing bovine babesiosis are Babesia bovis and B. bigemina, while B. caballi and Theileria equi are responsible for equine piroplasmosis. Treatment and control of these diseases are usually achieved using potentially toxic chemotherapeutics, such as imidocarb diproprionate, but drug-resistant para...

Background: The most common apicomplexan parasites causing bovine babesiosis are Babesia bovis and B. bigemina, while B. caballi and Theileria equi are responsible for equine piroplasmosis. Treatment and control of these diseases are usually achieved using potentially toxic chemotherapeutics, such as imidocarb diproprionate, but drug-resistant para...

Background: The tick-borne intra-erythrocytic apicomplexan Babesia caballi is one of the etiological agents of equine babesiosis, an economically important disease of equids in most tropical and subtropical areas of the world. Discovering candidate antigens for improved diagnostic tools and vaccines remains needed for controlling equine babesiosis...

Theileria parva is the causative agent of East Coast Fever (ECF), a tick-borne disease that kills over a million cattle each year in sub-Saharan Africa. Immune protection against T. parva involves CD8 ⁺ cytotoxic T cell response to parasite-infected cells. However, there is currently a paucity of knowledge regarding the role played by innate immune...

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....

Background Babesia bigemina is an apicomplexan parasite transovarially transmitted via Rhipicephalus ticks that infect red blood cells and causes bovine babesiosis, a poorly controlled severe acute disease in cattle. New methods of control are urgently needed, including the development of transmission blocking vaccines (TBV). Babesia bigemina repro...

East Coast Fever (ECF), caused by the tick-borne apicomplexan parasite Theileria parva, is a leading cause of morbidity and mortality in cattle of sub-Saharan Africa. The infection and treatment method (ITM) is currently the only vaccine available to control T. parva. Although ITM elicits levels of protection, its widespread adoption is limited by...

Theileria parva kills over one million cattle annually in sub-Saharan Africa. Parasite genetic complexity, cellular response immunodominance, and bovine MHC diversity have precluded traditional vaccine development. One potential solution is gene gun (GG) immunization, which enables simultaneous administration of one or more DNA-encoded antigens. Al...

Background: Bovine babesiosis is caused by apicomplexan pathogens of the genus Babesia such as B. bigemina and B. bovis. These tick-borne pathogens have a complex life-cycle involving asexual multiplication in vertebrate hosts and sexual reproduction in invertebrate vectors. In the tick midgut, extracellular Babesia parasites transform into gamete...

Babesia bovis, is a tick borne apicomplexan parasite responsible for important cattle losses globally. Babesia parasites have a complex life cycle including asexual replication in the mammalian host and sexual reproduction in the tick vector. Novel control strategies aimed at limiting transmission of the parasite are needed, but transmission blocki...

Western blot analysis using antibodies against a HAP2 synthetic peptide reacted against the recombinant version of HAP2. Lane 1: Bacterial lysate derived from arabinose induced recombinant bacteria; Lane 2: Bacterial lysate derived from non-arabinose induced recombinant bacteria. Size markers (M) in kDa are indicated at the left side. (TIF)

Green fluorescent parasites from Tf-hap2KO-gfp-bsd-cln xanthurenic acid-induced culture at 26°C, nuclei stained with Hoechst. (TIF)

Transcriptional analysis of hap2 and rap1 of B. bovis cultured blood stages. A. Microarray analysis of the virulent and attenuated parasites derived from B. bovis T2B strain. The Y axis indicates relative transcriptional levels. The X axis represents the name of the parasite strain. B. RNA seq analysis performed on the virulent and attenuated paras...

Western blot analysis using antibodies against HAP2, performed on Lane 1: induced (IC) B. bovis wild type parasites; Lane 2: induced (IC) B. bovis Tf-hap2KO-gfp-bsd-cln parasites developed in in vitro cultures. Monoclonal RAP-1 antibodies were used to detect B. bovis RAP-1 protein as a positive control. Size markers (M) in kDa are indicated at the...

Coxiella burnetii is the causative agent of Q fever, a zoonotic disease that threatens both human and animal health. Due to the paucity of experimental animal models, little is known about how host factors interface with bacterial components and affect pathogenesis. Here we used Drosophila melanogaster , in conjunction with the BSL2 Nine Mile phase...

Insects are not only major vectors of mammalian viruses, but are also host to insect-restricted viruses that can potentially be transmitted to mammals. While mammalian innate immune responses to arboviruses are well studied, less is known about how mammalian cells respond to viruses that are restricted to infect only invertebrates. Here we demonstr...

Inactivated IIV-6 does not elicit an immune response in MEFs. MEFs were infected with IIV-6, (A) heat-inactivated IIV-6, or (B) UV-inactivated IIV-6 at an MOI of 1 TCID50/cell. Supernatant from infected cells was collected and analyzed for IFN-β secretion with ELISA. Each virus infection was compared to mock for each time point, and all experiments...

IIV-6 does not replicate in MEFs. (A) MEFs or (B) S2 cells were infected with IIV-6 at an MOI of 1 TCID50/cell. 24 hours post-infection cells were collected and genomic DNA was isolated and quantified for IIV-6 capsid levels by qPCR. (B) The number of genome copies increased significantly in S2 cells from 0 to 48 hours post-infection and beyond (*,...

IIV-6 does not replicate in RIG-I-deficient MEFs. RIG-I+/+ and RIG-I-/- MEFs were infected with IIV-6 at an MOI of 1 TCID50/cell. Supernatants were collected and titered onto S2 cells to determine viral load over time. IIV-6 concentration did not increase significantly by 5 days post-infection in MEFs. (TIF)

IIV-6 removal and cell viability during priming and co-infection experiments. (A) Supernatant from mock- or IIV-6-infected MEFs was collected, centrifuged at 15,000 RCF for 10 minutes [44] and titered onto S2 cells to determine viral load. Supernatant from IIV-6-infected cells contains no detectable levels of virus after centrifugation. Assay was c...

IFN-β induction following IIV-6 infection is reduced in the absence of RIG-I. STING-/-, RIG-I-/-, MDA5-/-, Dicer-/-, or MAVS-/- MEFs and their corresponding wild-type MEFs were infected with IIV-6 at an MOI of 1 TCID50/cell in biological duplicate. Total RNA was collected at 24 hours post-infection and analyzed for IFN-β mRNA using qRT-PCR. Knockou...

IIV-6 causes a cytopathic effect in MEFs. (A) MEFs were infected with IIV-6 at an MOI of 1 TCID50/cell and imaged at 24 hours post-infection by phase contrast microscopy. Infected cells have a rounded morphology, unlike the mock-infected MEFs. (B) Mock- or IIV-6-infected cells were stained with trypan blue and counted using a hemocytometer. Each ba...

Ticks are blood-feeding arthropods that can affect human and animal health both directly by blood-feeding and indirectly by transmitting pathogens. The cattle tick Rhipicephalus (Boophilus) microplus is one of the most economically important ectoparasites of bovines worldwide and it is responsible for the transmission of the protozoan Babesia bovis...

Accession numbers

Rhipicephalus microplus is an obligate hematophagous ectoparasite of cattle and an important biological vector of Anaplasma marginale in tropical and subtropical regions. The primary determinants for A. marginale transmission are infection of the tick gut, followed by infection of salivary glands. Transmission of A. marginale to cattle occurs via i...

Babesia bovis is a tick-borne intraerythocytic protozoan responsible for acute disease in cattle which can be controlled by vaccination with attenuated B. bovis strains. Emerging B. bovis transfection technologies may increase the usefulness of these live vaccines. One use of transfected B. bovis parasites may be as a vaccine delivery platform. Pre...

Tick-borne pathogens that cause persistent infection are of major concern to the livestock industry because of transmission risk from persistently infected animals and the potential economic losses they pose. The recent reemergence of Theileria equi in the United States prompted a widespread national survey resulting in identification of limited di...

Members of the CCp protein family have been previously described to be expressed on gametocytes of apicomplexan Plasmodium parasites. Knocking out Plasmodium CCp genes blocks the development of the parasite in the mosquito vector, making the CCp proteins potential targets for the development of a transmission-blocking vaccine. Apicomplexans Babesia...

Multiple sequence alignments of CCp1 by CLUSTALW2. CCp2 amino acid sequences from Babesia bovis (Texas strain), Theileira equi (Florida isolate), Plasmodium falciparum (3D7 strain) and Plasmodium vivax (Sal-1 strain) were analyzed. Red line indicates the predicted location of the LCCL signature domains of the CCp protein family. Green line indicate...

Multiple sequence alignments of CCp2 by CLUSTALW2. CCp3 amino acid sequences from Babesia bovis (Texas strain), Theileira equi (Florida isolate), Plasmodium falciparum (3D7 strain) and Plasmodium vivax (Sal-1 strain) were analyzed. Red line indicates the predicted location of the LCCL signature domains of the CCp protein family. Green lines indicat...

Gene name, primer sequence, amplicon size and parameters of PCR efficiency of the CCp genes in Babesia bovis ( Bb ), Babesia bigemina ( Bbg ) and Theileria equi ( Te ). (DOC)

Total RNA samples were analyzed by the Experion Automated Electrophoresis System (Bio-Rad). Panel A shows a typical electropherogram of total RNA samples from Babesia bovis-infected bovine blood (The relative positions of 18S rRNA and 28S rRNA are indicated). Panel B shows a typical microfluidic electrophoresis of four representative RNA samples (1...

Multiple sequence alignments of CCp2 by CLUSTALW2. CCp3 amino acid sequences from Babesia bovis (Texas strain), Theileira equi (Florida isolate), Plasmodium falciparum (3D7 strain) and Plasmodium vivax (Sal-1 strain) were analyzed. Red lines indicate the predicted location of the LCCL signature domains of the CCp protein family. Green lines indicat...

Presence of CCp1-3 transcripts in cultures of Babesia bovis, Babesia bigemina and Theileria equi kept at 37°C. Results without reverse transcriptase (RT-) are shown for each gene and parasite. (TIFF)

Immunofluorescence assays of pre-immune sera, normal bovine serum, anti-mouse FITC conjugate, anti-rabbit FITC conjugate, and anti-bovine FITC conjugate. Mouse and rabbit pre-immune sera were used at a 1∶20 dilution. Normal bovine sera were used at a 1∶20 dilution. Anti-mouse, anti-rabbit, or anti-bovine FITC conjugates were used at a 1∶80 dilution...

Objective: The Babesia bovis genome encodes a rap-1 related gene denominated RAP-1 related antigen (RRA). In this study, we analysed the pattern of expression, immunogenicity and functional relevance of RRA. Methods: Phylogenetic analysis was performed using the program Phylip. Expression of rra was analysed by Northern blots, RT-PCR, immunoprec...

The spleen is a critical organ in defence against haemoparasitic diseases like babesiosis. Many in vitro and ex vivo studies have identified splenic cells working in concert to activate mechanisms required for successful resolution of infection. The techniques used in those studies, however, remove cells from the anatomical context in which cell in...

Rhipicephalus (Boophilus) microplus is an economically important tick of cattle involved in the transmission of Babesia bovis, the etiological agent of bovine babesiosis. Commercial anti-tick vaccines based on the R. microplus Bm86 glycoprotein have shown some effect in controlling tick infestation; however their efficacy as a stand-alone solution...

Over the past several years, innate immunity has been recognized as having an important role as a front-line defense mechanism and as an integral part of the adaptive immune response. Innate immunity in cattle exposed to hemoparasites is spleen-dependent and age-related. In this review, we discuss general aspects of innate immunity and the cells in...