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Ikuo Igarashi - One of the best experts on this subject based on the ideXlab platform.

  • Evaluation of The In Vitro And In Vivo Inhibitory Effects of Enrofloxacin On the Growth of Babesia Species and Theileria equi
    Drug and Drug Abuse, 2019
    Co-Authors: Ikuo Igarashi, Mahmoud Aboulaila, Naoaki Yokoyama, Akram Salama, Amer Abdel-aziz, Rehab Mady, Soad Menshawy
    Abstract:

    Objectives: Enrofloxacin, a fluoroquinolone antibiotic, is an inhibitor of prokaryotic topoisomerase II with antibacterial and antiparasitic activities. The study aimed to evaluate the inhibitory effect of enrofloxacin on Babesia species and Theileria equi in vitro and in vivo. Methods: The inhibitory effects of enrofloxacin were evaluated in vitro cultures using in vitro inhibition assay of three Babesia species and Theileria equi; furthermore, the in vivo inhibitory effect of enrofloxacin was evaluated in the mice model of Babesia microti. Results: The IC50 values of enrofloxacin were 4.9, 4.5, 4, and 3.9 nM for B. bovis, B. bigemina, B. caballi, and B. equi, respectively. Enrofloxacin at a dose rate of 10 mg/kg resulted in a 92.9 % inhibition of Babesia microti growth in BALB/c mice. Combination therapy of enrofloxacin at a dose rate of 5 mg/kg with diminazene aceturate at a dose rate of 12.5 mg/kg resulted in 93.83 % inhibition of Babesia microti growth in BALB/c mice. Conclusions: Enrofloxacin might be used for drug therapy in babesiosis

  • Cocktail of Theileria equi antigens for detecting infection in equines
    Asian Pacific Journal of Tropical Biomedicine, 2015
    Co-Authors: Shimaa Abd El-salam El-sayed, Naoaki Yokoyama, Mohamed Abdo Rizk, M. A. Terkawi, Ahmed Abdelmoniem Mousa, El Said El Shirbini El Said, Gehad El-sayed, Mohamed A. Fouda, Ikuo Igarashi
    Abstract:

    Abstract Objective To use two diagnostic antigens belonging to the frequently associated in Theileria domain, Theileria equi ( T. equi ) protein 82 (Te 82) and T. equi 104 kDa microneme-rhoptry antigen precursor (Te 43), to diagnose T. equi infection in horses as compared with equi merozoite antigen-2 (EMA-2). Methods In the current study, we applied a cocktail-ELISA containing two antigens (EMA-2 + Te 82) to diagnose T. equi infection either in experimentally infected horses or in field infection. Results Our findings have revealed that a cocktail formula of EMA-2 + Te 82 provided a more practical and sensitive diagnostic candidate for diagnosing T. equi infection in horses as compared with Te 82 or Te 43 alone. Conclusions The ELISA technique using a cocktail formula of EMA-2 + Te 82 offers a practical and sensitive diagnostic tool for diagnosing T. equi infection in horses and using of this promising cocktail formula will be applicable for epidemiological surveys and will help control the infection in horses.

  • Inhibitory effect of allicin on the growth of Babesia and Theileria equi parasites
    Parasitology Research, 2014
    Co-Authors: Akram Ahmed Salama, Mahmoud Aboulaila, Mohamad Alaa Terkawi, Ahmed Mousa, Ahmed El-sify, Mahmoud Allaam, Ahmed Zaghawa, Naoaki Yokoyama, Ikuo Igarashi
    Abstract:

    Allicin is an active ingredient of garlic that has antibacterial, antifungal, antiviral, and antiprotozoal activity. However, the inhibitory effects of allicin on Babesia parasites have not yet been examined. In the present study, allicin was tested as a potent inhibitor against the in vitro growth of bovine and equine Babesia parasites and the in vivo growth of Babesia microti in a mouse model. The in vitro growth of Babesia bovis , Babesia bigemina , Babesia caballi , or Theileria equi was inhibited by allicin in a dose-dependent manner and had IC_50 values of 818, 675, 470, and 742 μM, respectively. Moreover, allicin significantly inhibited ( P  

  • Inhibitory effect of allicin on the growth of Babesia and Theileria equi parasites
    Parasitology research, 2013
    Co-Authors: Akram Salama, Mahmoud Aboulaila, Mohamad Alaa Terkawi, Mahmoud Allaam, Ahmed Zaghawa, Naoaki Yokoyama, Ahmed Abdelmoniem Mousa, Ahmed Elsify, Ikuo Igarashi
    Abstract:

    Allicin is an active ingredient of garlic that has antibacterial, antifungal, antiviral, and antiprotozoal activity. However, the inhibitory effects of allicin on Babesia parasites have not yet been examined. In the present study, allicin was tested as a potent inhibitor against the in vitro growth of bovine and equine Babesia parasites and the in vivo growth of Babesia microti in a mouse model. The in vitro growth of Babesia bovis, Babesia bigemina, Babesia caballi, or Theileria equi was inhibited by allicin in a dose-dependent manner and had IC50 values of 818, 675, 470, and 742 μM, respectively. Moreover, allicin significantly inhibited (P < 0.001) invasion of B. bovis, B. bigemina, B. caballi, and T. equi into the host erythrocyte. Furthermore, mice treated with 30 mg/kg of allicin for 5 days significantly (P < 0.05) reduced the parasitemia of B. microti over the period of the study. To further examine the potential synergism of allicin with diminazene aceturate, growth inhibitory assays were performed in vitro and in vivo. Interestingly, combinations of diminazene aceturate with allicin synergistically potentiated its inhibitory effects in vitro and in vivo. These results indicate that allicin might be beneficial for the treatment of babesiosis, particularly when used in combination with diminazene aceturate.

  • Theileria equi merozoite antigen 2 interacts with actin molecule of equine erythrocyte during their asexual development
    Experimental Parasitology, 2012
    Co-Authors: Sanjay Kumar, Noboru Inoue, Ikuo Igarashi, Chihiro Sugimoto, Naoaki Yokoyama, Xuenan Xuan, Jungyeon Kim, Sabine Borkmimm
    Abstract:

    Theileria equi is a tick-transmitted intraerythrocytic protozoan parasite in equids. equine merozoite antigen (EMA)-1 and EMA-2 of T. equi have been identified as immunodominant proteins co-expressed on the surface of extra-erythrocytic merozoites. Additionally, only the EMA-2 is shed into the cytoplasm of infected erythrocyte or inside the erythrocytic membrane during their early developmental stage. In this study, we initially performed West-Western blot analysis on Triton X-100-insoluble erythrocytic skeleton collected from a healthy horse, using a glutathione S-transferase (GST)-tagged recombinant EMA-1t or EMA-2t of T. equi. The results indicated positive interactions of actin and band 4.1 molecules in the equine erythrocytic skeleton only with the recombinant EMA-2t. Subsequently, we carried out GST pull-down assay using the recombinant antigens (as above) against solubilized lysate of equine erythrocytic skeleton, and confirmed the co-precipitation of actin molecule with EMA-2t, but not with the EMA-1t. The interaction of EMA-2 with host erythrocytic actin indicated its role in the pathobiology of T. equi infection within host erythrocytes.

Donald P Knowles - One of the best experts on this subject based on the ideXlab platform.

  • First Detection of Diffuse and Cerebral Theileria equi Infection in Neonatal Filly
    Journal of Equine Veterinary Science, 2018
    Co-Authors: Maayan Margalit Levi, Donald P Knowles, Sharon Tirosh-levy, Roee Dahan, Dalia Berlin, Amir Steinman, Nir Edery, Igor Savitski, Benjamin Lebovich, Carlos E. Suarez
    Abstract:

    Abstract Theileria equi is a tick-borne hemoparasite that may cause severe illness in equids. Intrauterine transmission of T. equi can occur and may result in abortion, stillbirth, or neonatal piroplasmosis of foals. Theileria equi and Babesia caballi infection are present in Israel, and subclinical infection with T. equi is highly prevalent. Here, we describe a case of a neonatal piroplasmosis that manifested with diffuse and cerebral T. equi infection. A Quarter Horse filly was born to a mare chronically infected with T. equi. The filly was born weak, could not stand and suckle, and had jaundice, pigmenturia, and died within hours from parturition. High T. equi parasitemia was detected in stained blood smears and imprint smears of different organs, further confirmed by polymerase chain reaction and sequence analysis. Intraerythrocytic parasites were also found in brain capillaries. Theileria equi infection in brain, to our knowledge, has never been reported previously. In vitro culture from the mare's blood enabled isolation of T. equi parasites. Phylogenetic analysis of the T. equi 18S rRNA gene from the dam's isolate and from the filly was identical and showed high similarity to previously reported T. equi sequences from Israel. Further studies should be done to determine whether the cerebral infection observed here was caused by the phenotypic particularities of the T. equi strain involved or resulted from intrinsic/unique characteristics of the immune responses elicited by the parasite in the infected foal.

  • Assessment of Draxxin® (tulathromycin) as an inhibitor of in vitro growth of Babesia bovis, Babesia bigemina and Theileria equi
    Elsevier, 2018
    Co-Authors: Marta G. Silva, Donald P Knowles, Nicolas F. Villarino, Carlos E. Suarez
    Abstract:

    Babesia bovis, Babesia bigemina and Theileria equi are worldwide tick-borne hemoprotozoan that cause diseases characterized by fever, anemia, weight loss and abortion. A common feature of these diseases are transition from acute to chronic phases, in which parasites may persist in the host for life, and becoming a reservoir for tick transmission. The live-attenuated vaccines for B. bovis and B. bigemina are not available for worldwide use due to legal restrictions and other concerns such as potential erythrocyte antigen and pathogen contamination, and a vaccine for T. equi is not available. The use of chemotherapeutics is essential to treat and control these diseases, but several studies have shown the development of drug-resistance by these parasites, and safe and effective alternative drugs are needed. Tulathromycin, a macrolide antibiotic, has proven to be effective against a vast range of bacteria and Plasmodium yoelli, a Babesia and Theileria related intra-erythrocytic apicomplexan. Draxxin® (tulathromycin) is currently licensed to treat infections that cause respiratory diseases in cattle in several countries. In this study, the activity of Draxxin® was tested in vitro on cultured B. bovis, B. bigemina and T. equi. Addition of the drug to in vitro cultures resulted in cessation of parasite replication of the three species tested, B. bovis, B. bigemina and T. equi, with estimated IC50 of 16.7 ± 0.6 nM; 6.2 ± 0.2 nM and 2.4 ± 0.1 nM, respectively, at 72 h. Furthermore, neither parasites nor parasite DNA were detectable in cultures treated with IC100, suggesting Draxxin® is a highly effective anti-Babesia/Theileria drug. Importantly, the IC50 calculated for Draxxin® for the Babesia/Theileria parasites tested is lower that the IC50 calculated for some drugs currently in use to control these parasites. Collectively, the data strongly support in vivo testing of Draxxin® for the treatment of bovine babesiosis and equine piroplasmosis. Keywords: Draxxin®, Tulathromycin, Babesia bovis, Babesia bigemina, Theileria equi, In vitro inhibition growt

  • Inhibition of the in vitro growth of Babesia bigemina, Babesia caballi and Theileria equi parasites by trifluralin analogues.
    Ticks and tick-borne diseases, 2017
    Co-Authors: Marta G. Silva, Donald P Knowles, Sandra Antunes, Ana Domingos, Maria A. Esteves, Carlos E. Suarez
    Abstract:

    Abstract Bovine and equine babesiosis caused by Babesia bovis, Babesia bigemina and Babesia caballi, along with equine theileriosis caused by Theileria equi are global tick-borne hemoprotozoan diseases characterized by fever, anemia, weight losses and abortions. A common feature of these diseases are transition from acute to chronic phases, in which parasites may persist in the hosts for life. Antiprotozoal drugs are important for managing infection and disease. Previous research demonstrated that trifluralin analogues, designated (TFLAs) 1–15, which specifically bind to regions of alpha-tubulin protein in plants and protozoan parasites, have the ability to inhibit the in vitro growth of B. bovis. The inhibitory activity of TFLAs 1–15 minus TFLA 5 was tested in vitro against cultured B. bigemina, B. caballi and T. equi. The four TFLAs with greatest inhibitory activity were then analyzed for hemolytic activity and toxicity against erythrocytes. All TFLAs tested in the study showed inhibitory effects against the three parasite species. TFLA 2, TFLA 11, TFLA 13 and TFLA 14 were the most effective inhibitors for the three species tested, with estimated IC50 between 5.1 and 10.1 μM at 72 h. The drug’s solvent (DMSO/ethanol) did not statistically affect the growth of the parasites nor cause hemolysis. Also, TFLA 2, 13 and 14 did not cause statistically significant hemolytic activity on bovine and equine erythrocytes at 15 μM, and TFLA 2, 11 and 13 had no detectable toxic effects on bovine and equine erythrocytes at 15 μM, suggesting that these drugs do not compromise erythrocyte viability. The demonstrated ability of the trifluralin analogues to inhibit in vitro growth of Babesia spp. and Theileria equi, and their lack of toxic effects on erythrocytes supports further in vivo testing and eventually their development as novel alternatives for the treatment of babesiosis and theileriosis.

  • Assessment of Theileria equi and Babesia caballi infections in equine populations in Egypt by molecular, serological and hematological approaches
    Parasites & vectors, 2016
    Co-Authors: Mona S. Mahmoud, Lowell S Kappmeyer, Donald P Knowles, Marta G. Silva, Nadia T. Abu El-ezz, Sobhy Abdel-shafy, Somia A. Nassar, Amira H. El Namaky, Wagdy K. B. Khalil, Carlos E. Suarez
    Abstract:

    equine piroplasmosis (EP) caused by Theileria equi, Babesia caballi, or both, contributes to significant economic loss in the equine industry and remains uncontrolled in Egypt. This study focuses on surveying T. equi and B. caballi infections and hematological disorders in equine populations in Egypt. Theileria equi and B. caballi infections were assessed in blood from 88 horses and 51 donkeys in Egypt using light microscopy, indirect immunofluorescent antibody test (IFAT), nested PCR (nPCR), and competitive-ELISA (cELISA) assays. PCR products were examined for specificity by DNA sequencing. Hematological alterations were evaluated using a standard cell counter. Microscopic analysis revealed EP infection in 11.4 % and 17.8 % of horses and donkeys respectively. IFAT detected 23.9 % and 17.0 % infection of T. equi and B. caballi, respectively, in horses, and 31.4 % of T. equi and B. caballi in donkeys. T. equi cELISA detected 14.8 % and 23.5 % positive horses and donkeys, respectively, but the B. caballi RAP-1-based cELISA failed to detect any positives, a result hypothesized to be caused by sequence polymorphism found in the rap-1 genes. Nested-PCR analysis identified 36.4 % and 43.1 % positive horses and donkeys, respectively for T. equi and it also identified 19.3 % and 15.7 % positive horses and donkeys, respectively for B. caballi. The overall EP incidence found in the population under study was relatively high and comparable regardless of the diagnostic method used (56.8 % using nPCR and 48.9 % using IFAT). Hematologic analysis revealed macrocytic hypochromic anemia and thrombocytopenia in all piroplasma-infected horses. The data confirm relatively high levels of EP, likely causing hematological abnormalities in equines in Egypt, and also suggest the need for an improved serological test to diagnose B. caballi infection in this region.

  • Theileria equi isolates vary in susceptibility to imidocarb dipropionate but demonstrate uniform in vitro susceptibility to a bumped kinase inhibitor.
    Parasites & Vectors, 2015
    Co-Authors: Siddra A Hines, Joshua D Ramsay, Lowell S Kappmeyer, Audrey Ot Lau, Kayode K Ojo, Wesley C Van Voorhis, Donald P Knowles, Robert H Mealey
    Abstract:

    Background The apicomplexan hemoparasite Theileria equi is a causative agent of equine piroplasmosis, eradicated from the United States in 1988. However, recent outbreaks have sparked renewed interest in treatment options for infected horses. Imidocarb dipropionate is the current drug of choice, however variation in clinical response to therapy has been observed.

Amir Steinman - One of the best experts on this subject based on the ideXlab platform.

  • Infection dynamics of Theileria equi in carrier horses is associated with management and tick exposure.
    Ticks and tick-borne diseases, 2020
    Co-Authors: Sharon Tirosh-levy, Yuval Gottlieb, Monica L. Mazuz, I. Savitsky, Amir Steinman
    Abstract:

    The tick-borne equine hemoparasite, Theileria equi, is endemic in many parts of the world where prevalence may be high, and most infected horses are apparently healthy but serve as life-long carriers. To determine the factors that affect T. equi dynamics, we followed parasitic loads in apparently healthy horses at four time points during one year. A total of 1094 blood samples were collected from 395 horses, along with ticks and demographic and clinical data. Infection and load of T. equi were tested by PCR and qPCR, and for the spring dataset, infection was also tested serologically by IFAT (n = 268). Theileria equi was molecularly detected in 64.8 % of the horses. The agreement between molecular and serological results was 79.8 % (K > 0.674) and positively correlated with parasitic load. Infection was associated with pale mucus membranes, lower packed cell volume and higher total solids (all P < 0.001), although these changes had only minor clinical importance. While parasitic loads in qPCR-positive samples (n = 561) were generally low (mean = 7.9-10-4% parasitized erythrocytes), younger horses showed higher loads, possibly suggesting development of immunity. Infection and parasitic load were associated with housing management and tick exposure, illustrating different patterns of exposure. Endemic stability is suggested in pasture farms with constant exposure to ticks, where parasite prevalence was high (96 %) and associated with T. equi 18S rRNA genotype D, low parasitemia and high antibody titers. Endemic instability can be suggested in case were horses are kept in paddocks (prevalence = 49 %) with intermittent exposure to ticks, where infection was associated with high parasitemia when ticks were present. A steady state is suggested in stabled horses (prevalence = 46 %), with no exposure to ticks; where infection was associated with genotype A, low parasitemia and low antibody titers. The ability to identify different risk groups within endemic areas may improve the administration of suitable treatment and control practices in an effort to reduce the risk of clinical disease.

  • Potential tick vectors for Theileria equi in Israel.
    Medical and veterinary entomology, 2020
    Co-Authors: Sharon Tirosh-levy, Amir Steinman, A. Einhorn, D. A. Apanaskevich, Kosta Y. Mumcuoglu, Yuval Gottlieb
    Abstract:

    Theileria equi Mehlhorn and Schein, 1998 (Piroplasmida: Babesiidae) is an important tick-borne pathogen of horses that is highly endemic in many parts of the world, including Israel. The present study evaluated the potential roles of five hard tick species [Hyalomma excavatum Koch, 1844; Hyalomma marginatum Koch, 1844; Rhipicephalus turanicus Pomerantsev 1936; Rhipicephalus annulatus Say, 1821; Haemaphysalis parva (Neumann, 1897) (all: Ixodida: Ixodidae)], previously found to infest horses in Israel, in acting as vectors for piroplasmosis. For this, DNA was extracted from whole ticks and, when possible, from the salivary glands in each species (n = 10-59). Polymerase chain reaction amplification and sequencing of the 18S rRNA gene were used to detect T. equi in 48 of the 127 ticks (37.8%) and in 21 of the 90 extracted salivary glands (23.3%) in all five species. All but two sequences were classified as T. equi genotype A; the remaining two were classified as genotype D. The findings of this study point to Ha. parva and R. annulatus as potential novel vectors of T. equi, and suggest that parasite genotype selection occurs within the tick vector.

  • Stress conditions do not affect Theileria equi parasitemia levels in sub-clinically infected horses.
    Ticks and tick-borne diseases, 2020
    Co-Authors: Sharon Tirosh-levy, Yuval Gottlieb, Amir Steinman
    Abstract:

    Stress has been suggested as a risk factor for Theileria equi peracute disease and may lead to relapse in clinical signs in chronically infected horses. The aim of this study was to assess the effect of stress on T. equi parasitemia in sub-clinically infected horses in two settings: horses hospitalized at a veterinary teaching hospital and horses from an endurance farm. Blood samples were collected from the hospitalized horses (n = 32) upon admission (T0) and at discharge (T1) from the hospital, and results were compared between horses that underwent surgery (stress) and other hospitalized horses (control). Blood samples were collected from an endurance farm (n = 20) six weeks before (T0) and two days after (T1) participation in an 80-km endurance event, and results were compared between horses that participated (stress) or did not participate (control) in the event. Theileria equi parasite load was determined using qPCR, and T1/T0 ratio was calculated for each horse. Mean parasite load at both time points did not differ statistically between the stress group and the controls in both settings. Theileria equi genotype was determined based on the 18S rRNA gene, when possible. Parasite genotypes were similar to strains previously characterized in the region and classified as genotypes A and D. The results of this study contradict the common assumption that stress may lead to increased parasite load in horses with a subclinical T. equi infection.

  • Genetic characteristics of Theileria equi in zebras, wild and domestic donkeys in Israel and the Palestinian Authority
    Ticks and tick-borne diseases, 2019
    Co-Authors: Sharon Tirosh-levy, Yuval Gottlieb, Ori Arieli, Monica L. Mazuz, Roni King, Igal H. Horowitz, Amir Steinman
    Abstract:

    equine piroplasmosis (EP) is an important tick-borne disease of equids, caused by Theileria equi and Babesia caballi. It is endemic in most parts of the world, including Israel, and has clinical and economic consequences. This study was set to evaluate the presence of EP parasites in domestic donkeys and in wild equids in Israel and the Palestinian Authority (PA). To assess subclinical EP infection in 98 domestic donkeys (Equus africanus asinus), 9 Asiatic wild donkeys (Equus hemionus), 8 zebras (Equus quagga), 7 African wild donkeys (Equus africanus) and 5 mules, were tested using PCR and qPCR. Positive samples were characterized by amplification and sequencing of a 1600 bp fragment of the 18S rRNA gene. Babesia caballi was not detected in any of the animals. Theileria equi was detected in 32% of the donkeys, 89% of Asiatic wild donkeys, 57% of African wild donkeys, 62% of zebras and none of the mules. Parasitemia was low in all of the positive samples. Risk factors associated with infection in donkeys included one farm (Kiryat Gat) and animal sex (male). The sequences of the 18S rRNA gene from domestic donkeys were all similar, and belonged to the T. equi genotype D, similar to the genotype sequenced from horses in the same area, while sequences from wild donkeys were unique and belonged to the T. equi genotype A. Verification of the T. equi genotype in zebras could not be concluded, suggesting major genetic variation.

  • First Detection of Diffuse and Cerebral Theileria equi Infection in Neonatal Filly
    Journal of Equine Veterinary Science, 2018
    Co-Authors: Maayan Margalit Levi, Donald P Knowles, Sharon Tirosh-levy, Roee Dahan, Dalia Berlin, Amir Steinman, Nir Edery, Igor Savitski, Benjamin Lebovich, Carlos E. Suarez
    Abstract:

    Abstract Theileria equi is a tick-borne hemoparasite that may cause severe illness in equids. Intrauterine transmission of T. equi can occur and may result in abortion, stillbirth, or neonatal piroplasmosis of foals. Theileria equi and Babesia caballi infection are present in Israel, and subclinical infection with T. equi is highly prevalent. Here, we describe a case of a neonatal piroplasmosis that manifested with diffuse and cerebral T. equi infection. A Quarter Horse filly was born to a mare chronically infected with T. equi. The filly was born weak, could not stand and suckle, and had jaundice, pigmenturia, and died within hours from parturition. High T. equi parasitemia was detected in stained blood smears and imprint smears of different organs, further confirmed by polymerase chain reaction and sequence analysis. Intraerythrocytic parasites were also found in brain capillaries. Theileria equi infection in brain, to our knowledge, has never been reported previously. In vitro culture from the mare's blood enabled isolation of T. equi parasites. Phylogenetic analysis of the T. equi 18S rRNA gene from the dam's isolate and from the filly was identical and showed high similarity to previously reported T. equi sequences from Israel. Further studies should be done to determine whether the cerebral infection observed here was caused by the phenotypic particularities of the T. equi strain involved or resulted from intrinsic/unique characteristics of the immune responses elicited by the parasite in the infected foal.

Fábio Pereira Leivas Leite - One of the best experts on this subject based on the ideXlab platform.

  • Antigenicity assessment of the Theileria equi merozoite antigen (EMA-2) expressed in Pichia pastoris in mice and horses.
    Experimental parasitology, 2019
    Co-Authors: Ana Muñoz Vianna, Alice Correa Santos, Rodrigo Casquero Cunha, Ana Paula De Souza Stori De Lara, Guilherme Borges Weege, Fábio Pereira Leivas Leite
    Abstract:

    Abstract equine theileriosis is a severe equine disease caused by the protozoan Theileria equi, which is prevalent in tropical and subtropical areas. In this study, a recombinant equi merozoite antigen-2 (rEMA-2) of T. equi was used as an immunogen. Two groups of 10 mice each were divided into control and vaccinated groups. Sixty mares seronegative for theileriosis were divided in two groups, one vaccinated and another group as a control animal. Mice and mares of the vaccinated groups were inoculated with 150 μL of the vaccine containing 50 μg of rEMA-2 and 2 mL of the vaccine containing 200 μg of rEMA-2, respectively, at days 0 and 21. The immunogenicity of rEMA-2 was evaluated by ELISA and fluorescent antibody test (IFAT) using serum from vaccinated mice, mares and antigenicity in naturally infected horse. At every point throughout the ELISA study, there were significant differences between the vaccinated and control groups (p

  • Immunogenicity and antigenicity of the recombinant EMA-1 protein of Theileria equi expressed in the yeast Pichia pastoris Imunogenicidade e antigenicidade da proteína recombinante EMA-1 de Theileria equi expressa em Pichia pastoris
    2009
    Co-Authors: Leandro Quintana Nizoli, Sergio Silva Da Silva, Fabricio Rochedo Conceição, Luana Alves Dummer, Alceu Gonçalves Dos Santos, Fábio Pereira Leivas Leite
    Abstract:

    The equine piroplasmosis caused by Theileria equi is one of the most important parasitic diseases of the equine, causing damage to animal health and economic losses. In T. equi, 2 merozoite surface proteins, equi merozoite antigen EMA-1 and EMA-2, have been identified as the most immunodominant antigens. This suggests that these antigens might be used as immunobiological tools. The EMA-1 of Theileria equi was cloned and expressed in the yeast Pichia pastoris. The transformed yeast was grown at high cell density, expressing up to 389 mg.L –1 of recombinant protein. The protein was concentrated and detected in Dot blot. The recombinant product was antigenically similar to the native protein as determined using monoclonal antibodies, and polyclonal antibodies obtained from equines naturally infected with T. equi. The immunogenicity of rEMA-1 protein was demonstrated by IFAT using sera from recombinantprotein-immunized mice using aluminum hydroxide as adjuvant. All animals vaccinated with rEMA-1 developed a high specific antibody response. This results suggest that rEMA-1expressed in P. pastoris might be a strong candidate to be used as an antigen for immune diagnostics as well as a vaccine antigen.

  • Immunogenicity and antigenicity of the recombinant EMA-1 protein of Theileria equi expressed in the yeast Pichia pastoris
    Revista brasileira de parasitologia veterinaria = Brazilian journal of veterinary parasitology : Orgao Oficial do Colegio Brasileiro de Parasitologia , 2009
    Co-Authors: Leandro Quintana Nizoli, Sergio Silva Da Silva, Fabricio Rochedo Conceição, Luana Alves Dummer, Alceu Gonçalves Dos Santos, Fábio Pereira Leivas Leite
    Abstract:

    The equine piroplasmosis caused by Theileria equi is one of the most important parasitic diseases of the equine, causing damage to animal health and economic losses. In T. equi, 2 merozoite surface proteins, equi merozoite antigen EMA-1 and EMA-2, have been identified as the most immunodominant antigens. This suggests that these antigens might be used as immunobiological tools. The EMA-1 of Theileria equi was cloned and expressed in the yeast Pichia pastoris. The transformed yeast was grown at high cell density, expressing up to 389 mg.L-1 of recombinant protein. The protein was concentrated and detected in Dot blot. The recombinant product was antigenically similar to the native protein as determined using monoclonal antibodies, and polyclonal antibodies obtained from equines naturally infected with T. equi. The immunogenicity of rEMA-1 protein was demonstrated by IFAT using sera from recombinant-protein-immunized mice using aluminum hydroxide as adjuvant. All animals vaccinated with rEMA-1 developed a high specific antibody response. This results suggest that rEMA-1expressed in P. pastoris might be a strong candidate to be used as an antigen for immune diagnostics as well as a vaccine antigen.

Massaro W. Ueti - One of the best experts on this subject based on the ideXlab platform.

  • Amblyomma cajennense is an intrastadial biological vector of Theileria equi
    Parasites & vectors, 2013
    Co-Authors: Glen A. Scoles, Massaro W. Ueti
    Abstract:

    Background The apicomplexan hemoprotozoan parasite Theileria equi is one of the etiologic agents causing equine piroplasmosis, a disease of equines that is endemic throughout large parts of the world. Before 2009 the United States had been considered to be free of this parasite. Occasional cases had occurred but there was no evidence for endemic vector-borne transmission in the U.S. until a 2009 outbreak in Texas in which Dermacentor variabilis and Amblyomma cajennense were implicated as vectors. Although D. variabilis has previously been shown to be a competent laboratory vector, studies suggested A. cajennense was not a competent transstadial vector, even though the presence of this tick species on horses in South American is epidemiologicaly correlated with higher a prevalence of infection. In this study we tested the transstadial and intrastadial vector competence of D. variabilis and A. cajennense for T. equi.

  • Lymphocytes and Macrophages Are Infected by Theileria equi, but T Cells and B Cells Are Not Required to Establish Infection In Vivo
    PloS one, 2013
    Co-Authors: Joshua D Ramsay, Donald P Knowles, Massaro W. Ueti, Wendell C. Johnson, Glen A. Scoles, Robert H Mealey
    Abstract:

    Theileria equi has a biphasic life cycle in horses, with a period of intraleukocyte development followed by patent erythrocytic parasitemia that causes acute and sometimes fatal hemolytic disease. Unlike Theileria spp. that infect cattle (Theileria parva and Theileria annulata), the intraleukocyte stage (schizont) of Theileria equi does not cause uncontrolled host cell proliferation or other significant pathology. Nevertheless, schizont-infected leukocytes are of interest because of their potential to alter host cell function and because immune responses directed against this stage could halt infection and prevent disease. Based on cellular morphology, Theileria equi has been reported to infect lymphocytes in vivo and in vitro, but the specific phenotype of schizont-infected cells has yet to be defined. To resolve this knowledge gap in Theileria equi pathogenesis, peripheral blood mononuclear cells were infected in vitro and the phenotype of infected cells determined using flow cytometry and immunofluorescence microscopy. These experiments demonstrated that the host cell range of Theileria equi was broader than initially reported and included B lymphocytes, T lymphocytes and monocyte/macrophages. To determine if B and T lymphocytes were required to establish infection in vivo, horses affected with severe combined immunodeficiency (SCID), which lack functional B and T lymphocytes, were inoculated with Theileria equi sporozoites. SCID horses developed patent erythrocytic parasitemia, indicating that B and T lymphocytes are not necessary to complete the Theileria equi life cycle in vivo. These findings suggest that the factors mediating Theileria equi leukocyte invasion and intracytoplasmic differentiation are common to several leukocyte subsets and are less restricted than for Theileria annulata and Theileria parva. These data will greatly facilitate future investigation into the relationships between Theileria equi leukocyte tropism and pathogenesis, breed susceptibility, and strain virulence.

  • Efficacy of imidocarb dipropionate in eliminating Theileria equi from experimentally infected horses.
    Veterinary journal (London England : 1997), 2012
    Co-Authors: Juanita F. Grause, Lowell S Kappmeyer, Donald P Knowles, Massaro W. Ueti, Jeffrey T. Nelson, Thomas O. Bunn
    Abstract:

    Abstract Theileria equi, one of the causative agents of equine piroplasmosis, is endemic in many regions of the world but is considered a ‘foreign’ animal disease in the USA. In an effort to prevent the importation of T. equi, stringent serological screening of horses is practiced prior to entry to the USA. Current regulatory options available where horses are found to be infected include permanent quarantine with or without chemotherapy, repatriation, or euthanasia. Chemotherapeutics that eliminate infection and subsequently transmission risk are critical in the management of infected horses. In this study, the efficacy of the drug imidocarb dipropionate against experimental T. equi infection was assessed. Of nine horses experimentally inoculated with T. equi isolated from an animal previously imported from Peru, six were treated with imidocarb dipropionate after the resolution of the acute phase of the disease. Elimination of the parasite was demonstrated in 5/6 by nested PCR, blood transfusions to naive horses, and reversion to seronegative status. The findings support the use of this drug as a potential treatment option in controlling outbreaks of T. equi, and also suggest that ‘combination testing’ using both serological and PCR detection methods are necessary to demonstrate clearance of infection.

  • In vitro activity of ponazuril against Theileria equi.
    Veterinary parasitology, 2011
    Co-Authors: L Nicki Wise, Lowell S Kappmeyer, Massaro W. Ueti, Melissa T Hines, Stephen N White, Wendell Davis, Donald P Knowles
    Abstract:

    The equid hemoprotozoan parasite Theileria equi is endemic in most regions worldwide. Infection of horses is a cause of significant economic loss due to costs associated with disease and restriction of trade with non-endemic nations. The ability of certain drugs such as imidocarb dipropionate to eliminate persistent T. equi infection and transmission risk is controversial. The anti-protozoal agent ponazuril has been used successfully to treat equine Sarcosystis neurona and Toxoplasma gondii. The hypothesis that ponazuril inhibits replication of T. equi in vitro was tested. T. equi infected equine erythrocyte cultures were treated with ponazuril at multiple concentrations. Cessation of parasite replication was observed over a 5-day period and the degree of inhibition was variable between drug concentrations. Ponazuril inhibited T. equi in erythrocyte culture at all concentrations tested but parasite elimination required at least 500 μg/mL. The high dose of ponazuril required for in vitro inhibition likely limits its ability to control or clear T. equi infection in vivo, however additional research to evaluate related drugs is warranted.

  • Protective effects of passively transferred merozoite-specific antibodies against Theileria equi in horses with severe combined immunodeficiency.
    Clinical and vaccine immunology : CVI, 2011
    Co-Authors: Robert H Mealey, Lowell S Kappmeyer, Massaro W. Ueti, Bettina Wagner, Donald P Knowles
    Abstract:

    Theileria equi immune plasma was infused into young horses (foals) with severe combined immunodeficiency. Although all foals became infected following intravenous challenge with homologous T. equi merozoite stabilate, delayed time to peak parasitemia occurred. Protective effects were associated with a predominance of passively transferred merozoite-specific IgG3.