The Experts below are selected from a list of 285 Experts worldwide ranked by ideXlab platform
Gad Baneth - One of the best experts on this subject based on the ideXlab platform.
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Antibody response to Hepatozoon canis in experimentally infected dogs.
Veterinary parasitology, 1998Co-Authors: Gad Baneth, V. Shkap, E. Pipano, M Samish, I SavitskyAbstract:Canine hepatozoonosis is a disease caused by the tick-borne protozoan Hepatozoon canis. Five puppies were inoculated by ingestion of Rhipicephalus sanguineus ticks experimentally infected with H. canis, and all became infected with H. canis: gametocytes were detected in blood smears from four dogs and schizonts were observed in the spleen and bone marrow of the fifth. Antibodies reactive with H. canis gametocytes were detected by the indirect fluorescent antibody test (IFA), with IgM detected initially in all dogs 16 to 39 days post infection (PI) and IgG 22 to 43 days PI. The presence of gametocytes was first observed within peripheral blood neutrophils in Giemsa-stained blood smears between days 28 and 43 PI. Gametocyte-reactive antibodies were detected before the appearance of blood gametocytes in three of the four parasitemic dogs and also in a dog with no observed Parasitemia. The detection of serum antibodies prior to the detection of blood gametocytes, or without apparent Parasitemia, suggests that antibodies reactive with gametocytes may be formed against earlier forms of the parasite developing in the parenchymal tissues. Sera of dogs experimentally infected with Babesia canis, Babesia gibsoni and Ehrlichia canis exhibited no reactivity when tested with H. canis antigen. Additionally, sera positive for H. canis were not reactive with antigens of Toxoplasma gondii, Neospora caninum, Leishmania donovani and E. canis. In conclusion, incoculation of dogs with ticks infected with H. canis results in production of antibodies reactive with peripheral blood gametocytes. Detection of IgG titres would be beneficial for the diagnosis of progressive infections with undetectable Parasitemia, for seroprevalence studies, and as an adjunct to IgM titres in early infections.
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Hepatozoon canis infection in a litter of Dalmatian dogs
Veterinary parasitology, 1997Co-Authors: Gad Baneth, Itamar Aroch, B. Z. PresenteyAbstract:Abstract Infection with Hepatozoon canis is described in a litter of seven Dalmatians. Four littermates were presented with concurrent hepatozoonosis and parvoviral enteritis and the remaining three puppies were parasitemic with H. canis with no other concurrent disease. Parasitemia ranged between 3% and 67% of the blood neutrophils. The mean number of parasitized neutrophils per μl among littermates with concurrent hepatozoonosis and parvoviral enteritis was 1139 (±447 SD) on the day of admission, compared with 470 (±379) among littermates with hepatozoonosis only. Puppies with hepatozoonosis and parvovirus infection at admission differed significantly in their degree of H. canis Parasitemia from their littermates which were not infected with parvovirus ( P = 0.0286). Concurrent parvoviral enteritis and hepatozoonosis in the dog are reported here for the first time.
Ricardo T Gazzinelli - One of the best experts on this subject based on the ideXlab platform.
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contributions of ifn γ and granulysin to the clearance of plasmodium yoelii blood stage
PLOS Pathogens, 2020Co-Authors: Natalia Satchiko Hojosouza, Patrick Orestes De Azevedo, Julia Teixeira De Castro, Andrea Teixeiracarvalho, Judy Lieberman, Caroline Junqueira, Ricardo T GazzinelliAbstract:P. vivax-infected Retics (iRetics) express human leukocyte antigen class I (HLA-I), are recognized by CD8+ T cells and killed by granulysin (GNLY) and granzymes. However, how Plasmodium infection induces MHC-I expression on Retics is unknown. In addition, whether GNLY helps control Plasmodium infection in vivo has not been studied. Here, we examine these questions using rodent infection with the P. yoelii 17XNL strain, which has tropism for Retics. Infection with P. yoelii caused extramedullary erythropoiesis, reticulocytosis and expansion of CD8+CD44+CD62L- IFN-γ-producing T cells that form immune synapses with iRetics. We now provide evidence that MHC-I expression by iRetic is dependent on IFN-γ-induced transcription of IRF-1, MHC-I and β2-microglobulin (β2-m) in erythroblasts. Consistently, CTLs from infected wild type (WT) mice formed immune synapses with iRetics in an IFN-γ- and MHC-I-dependent manner. When challenged with P. yoelii 17XNL, WT mice cleared Parasitemia and survived, while IFN-γ KO mice remained parasitemic and all died. β2-m KO mice that do not express MHC-I and have virtually no CD8+ T cells had prolonged Parasitemia, and 80% survived. Because mice do not express GNLY, GNLY-transgenic mice can be used to assess the in vivo importance of GNLY. Parasite clearance was accelerated in GNLY-transgenic mice and depletion of CD8+ T cells ablated the GNLY-mediated resistance to P. yoelii. Altogether, our results indicate that in addition to previously described mechanisms, IFN-γ promotes host resistance to the Retic-tropic P. yoelii 17XNL strain by promoting MHC-I expression on iRetics that become targets for CD8+ cytotoxic T lymphocytes and GNLY.
I Savitsky - One of the best experts on this subject based on the ideXlab platform.
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Antibody response to Hepatozoon canis in experimentally infected dogs.
Veterinary parasitology, 1998Co-Authors: Gad Baneth, V. Shkap, E. Pipano, M Samish, I SavitskyAbstract:Canine hepatozoonosis is a disease caused by the tick-borne protozoan Hepatozoon canis. Five puppies were inoculated by ingestion of Rhipicephalus sanguineus ticks experimentally infected with H. canis, and all became infected with H. canis: gametocytes were detected in blood smears from four dogs and schizonts were observed in the spleen and bone marrow of the fifth. Antibodies reactive with H. canis gametocytes were detected by the indirect fluorescent antibody test (IFA), with IgM detected initially in all dogs 16 to 39 days post infection (PI) and IgG 22 to 43 days PI. The presence of gametocytes was first observed within peripheral blood neutrophils in Giemsa-stained blood smears between days 28 and 43 PI. Gametocyte-reactive antibodies were detected before the appearance of blood gametocytes in three of the four parasitemic dogs and also in a dog with no observed Parasitemia. The detection of serum antibodies prior to the detection of blood gametocytes, or without apparent Parasitemia, suggests that antibodies reactive with gametocytes may be formed against earlier forms of the parasite developing in the parenchymal tissues. Sera of dogs experimentally infected with Babesia canis, Babesia gibsoni and Ehrlichia canis exhibited no reactivity when tested with H. canis antigen. Additionally, sera positive for H. canis were not reactive with antigens of Toxoplasma gondii, Neospora caninum, Leishmania donovani and E. canis. In conclusion, incoculation of dogs with ticks infected with H. canis results in production of antibodies reactive with peripheral blood gametocytes. Detection of IgG titres would be beneficial for the diagnosis of progressive infections with undetectable Parasitemia, for seroprevalence studies, and as an adjunct to IgM titres in early infections.
Lili Yuan - One of the best experts on this subject based on the ideXlab platform.
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therapeutic responses of plasmodium vivax malaria to chloroquine and primaquine treatment in northeastern myanmar
Antimicrobial Agents and Chemotherapy, 2015Co-Authors: Lili Yuan, Ying Wang, Daniel M Parker, Bhavna Gupta, Zhaoqing Yang, Yuping Xiao, Guofa Zhou, Kevin J BairdAbstract:Chloroquine-primaquine (CQ-PQ) continues to be the frontline therapy for radical cure of Plasmodium vivax malaria. Emergence of CQ-resistant (CQR) P. vivax parasites requires a shift to artemisinin combination therapies (ACTs), which imposes a significant financial, logistical, and safety burden. Monitoring the therapeutic efficacy of CQ is thus important. Here, we evaluated the therapeutic efficacy of CQ-PQ for P. vivax malaria in northeast Myanmar. We recruited 587 patients with P. vivax monoinfection attending local malaria clinics during 2012 to 2013. These patients received three daily doses of CQ at a total dose of 24 mg of base/kg of body weight and an 8-day PQ treatment (0.375 mg/kg/day) commencing at the same time as the first CQ dose. Of the 401 patients who finished the 28-day follow-up, the cumulative incidence of recurrent Parasitemia was 5.20% (95% confidence interval [CI], 3.04% to 7.36%). Among 361 (61%) patients finishing a 42-day follow-up, the cumulative incidence of recurrent blood-stage infection reached 7.98% (95% CI, 5.20% to 10.76%). The cumulative risk of gametocyte carriage at days 28 and 42 was 2.21% (95% CI, 0.78% to 3.64%) and 3.93% (95% CI, 1.94% to 5.92%), respectively. Interestingly, for all 15 patients with recurrent gametocytemia, this was associated with concurrent asexual stages. Genotyping of recurrent parasites at the merozoite surface protein 3α gene locus from 12 patients with recurrent Parasitemia within 28 days revealed that 10 of these were the same genotype as at day 0, suggesting recrudescence or relapse. Similar studies in 70 patients in the same area in 2007 showed no recurrent Parasitemias within 28 days. The sensitivity to chloroquine of P. vivax in northeastern Myanmar may be deteriorating.
Jacob Golenser - One of the best experts on this subject based on the ideXlab platform.
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Optimisation of flow cytometric measurement of parasitaemia in plasmodium-infected mice.
International journal for parasitology, 2000Co-Authors: Daniel Barkan, Hagai Ginsburg, Jacob GolenserAbstract:Mouse malaria is often used as a model for drug testing. The results of drug trials are monitored by tedious (and consequently, sometimes inaccurate) microscopic counting of blood smears, or by flow cytometry. We suggest an improved, accurate and time-saving flow cytometric method for determination of parasitaemias in mice infected with Plasmodium vinckei petteri or Plasmodium berghei. The method involves collection of drops of blood from the tail vein, fixation, storage, permeabilisation, staining and analysis with a visible range flow cytometer. Three nucleic acid dyes, YOYO-1, propidium iodide and acridine orange were compared. YOYO-1 was found to be the best stain for the discrimination of parasitised erythrocytes from non-infected ones. A good direct correlation was obtained between parasitaemia determined by conventional microscopy and parasitaemia measured by flow cytometry. Drug effects could be assessed by the cytometric method. For the detection of low level of Parasitemia, parasitised cells were treated with RNAse to completely cancel RNA-derived signals originating from host reticulocytes. This procedure also revealed discrete peaks arising from red cells infected with multiple parasites or from parasites with different numbers of nuclei.
