Child ; Humans ; Toxoplasmosis, Cerebral ; Hematopoietic Stem Cell Transplantation ; Thalassemia

Humans ; Toxoplasmosis ; Hematopoietic Stem Cell Transplantation ; Hematologic Diseases

OBJECTIVE: To analyze the RNA binding protein of Toxoplasma gondii (TgDDX39) using bioinformatics technology, and to evaluate the immunogenicity of TgDDX39, so as to provide insights into development of toxoplasmosis vaccines. METHODS: The amino acid sequences of TgDDX39 were retrieved from the ToxoDB database, and the physicochemical properties, transmembrane structure domain, signal peptide sites, post-translational modification sites, coils, secondary and tertiary structures, hydrophobicity, and antigenic epitopes of the TgDDX39 protein were predicted using online bioinformatics tools, incluiding ProtParam, TMHMM 2.0, SignalP 5.0, NetPhos 3.1, COILS, SOPMA, Phyre2, ProtScale, ABCpred, SYFPEITHI and DNA-STAR. RESULTS: TgDDX39 protein was predicted to be an unstable hydrophilic protein with the molecular formula of C₂₁₇₃H₃₄₅₈N₅₉₈O₆₆₁S₁₈, which contained 434 amino acids and had an estimated molecular weight of 49.1 kDa and a theoretical isoelectric point of 5.55. The protein was predicted to have an extremely low possibility of signal peptides, without transmembrane regions, and contain 27 phosphorylation sites. The β turn and random coils accounted for 39.63% of the secondary structure of the TgDDX39 protein, and a coiled helix tended to produce in one site. In addition, the TgDDX39 protein contained multiple B and T cell antigenic epitopes. CONCLUSIONS Bioinformatics analyses predict that TgDDX39 protein has high immunogenicity and contains multiple antigenic epitopes. TgDDX39 protein is a potential candidate antigen for vaccine development.
Humans ; Toxoplasma/metabolism* ; Toxoplasmosis/prevention & control* ; Vaccines ; Epitopes, T-Lymphocyte ; Computational Biology ; Protozoan Proteins/chemistry*

We report a literature review and a case of ocular toxoplasmosis in a patient with multiple drug allergies, who was successfully treated with regular intravitreal clindamycin and subconjunctival dexamethasone. A Malay lady in her twenties presented to us with right eye blurring of vision of 2 weeks duration, which she described as a central scotoma. Visual acuity at presentation was hand movements. Examination revealed intense ocular inflammation. The right eye had anterior segment inflammation of 3+ cells with fine keratic precipitates, whilst the posterior segment revealed papillitis, vitritis, retinitis, choroiditis, vasculitis and hyperpigmented chorioretinal scar inferotemporal to fovea. Ocular coherence tomography showed intraretinal fluid and retinal thickening. Fluorescein angiography showed early hypofluorescence of the lesion with progressive hyperfluorescence and leakage from the optic disc. Immunoglobulin G serology of Toxoplasma gondii was raised and immunoglobulin M levels were normal. The patient developed an allergic reaction with classical antibiotic and antifolate therapy. She was successfully treated with regular two-weekly intravitreal clindamycin and subconjunctival dexamethasone and her best corrected visual acuity was 6/18 at the end of her treatment. Intravitreal injection of clindamycin and subconjunctival dexamethasone is a good option in patients of ocular toxoplasmosis who are allergic to oral medications.
Toxoplasmosis, Ocular

Toxoplasma gondii is a worldwide parasite that can infect almost all kinds of mammals and cause fatal toxoplasmosis in immunocompromised patients. Apoptosis is one of the principal strategies of host cells to clear pathogens and maintain organismal homeostasis, but the mechanism of cell apoptosis induced by T. gondii remains obscure. To explore the apoptosis influenced by T. gondii, Vero cells infected or uninfected with the parasite were subjected to apoptosis detection and subsequent dual RNA sequencing (RNA-seq). Using high-throughput Illumina sequencing and bioinformatics analysis, we found that pro-apoptosis genes such as DNA damage-inducible transcript 3 (DDIT3), growth arrest and DNA damage-inducible α (GADD45A), caspase-3 (CASP3), and high-temperature requirement protease A2 (HtrA2) were upregulated, and anti-apoptosis genes such as poly(adenosine diphosphate (ADP)-ribose) polymerase family member 3 (PARP3), B-cell lymphoma 2 (Bcl-2), and baculoviral inhibitor of apoptosis protein (IAP) repeat containing 5 (BIRC5) were downregulated. Besides, tumor necrosis factor (TNF) receptor-associated factor 1 (TRAF1), TRAF2, TNF receptor superfamily member 10b (TNFRSF10b), disabled homolog 2 (DAB2)‍-interacting protein (DAB2IP), and inositol 1,4,5-trisphosphate receptor type 3 (ITPR3) were enriched in the upstream of TNF, TNF-related apoptosis-inducing ligand (TRAIL), and endoplasmic reticulum (ER) stress pathways, and TRAIL-receptor 2 (TRAIL-R2) was regarded as an important membrane receptor influenced by T. gondii that had not been previously considered. In conclusion, the T. gondii RH strain could promote and mediate apoptosis through multiple pathways mentioned above in Vero cells. Our findings improve the understanding of the T. gondii infection process through providing new insights into the related cellular apoptosis mechanisms.
Animals ; Apoptosis ; Chlorocebus aethiops ; Gene Expression Profiling ; Humans ; Mammals/genetics* ; Toxoplasma/genetics* ; Toxoplasmosis/pathology* ; Vero Cells ; ras GTPase-Activating Proteins/genetics*

A 36-year-old-male was admitted complaining of headache, right sided weakness and numbness of upper and lower extremity, and multiple cranial nerve deficits. Cranial magnetic resonance imaging revealed an abscess in the pontomesencephalic junction. Patient was then diagnosed to have Human Immunodeficiency Virus with a CD 4 count of 32 cells/ uL, his CSF assay was positive for Toxoplasmosis IgG and was managed as a case of probable brainstem toxoplasmosis. Patient was treated with Co-Trimoxazole 800/160mg 2 tablets twice a day. Upon discharge the patient clinically improved and was tolerating oral feeding. A repeat cranial magnetic resonance imaging after 6 weeks of antibiotic treatment revealed a decrease of size in the previous lesion. To our knowledge, there are no reported cases in the Philippines that shows the documentation of CNS toxoplasmosis in the brainstem. In this paper, a case of CNS toxoplasmosis in the pons of a newly diagnosed HIV patient is presented and how its course led to a good outcome.
Toxoplasmosis ; Immunocompromised Host

Both Plasmodium spp. and Toxoplasma gondii are important apicomplexan parasites, which infect humans worldwide. Genetic analyses have revealed that 33% of amino acid sequences of inner membrane complex from the malaria parasite Plasmodium berghei is similar to that of Toxoplasma gondii. Inner membrane complex is known to be involved in cell invasion and replication. In this study, we investigated the resistance against T. gondii (ME49) infection induced by previously infected P. berghei (ANKA) in mice. Levels of T. gondii-specific IgG, IgG1, IgG2a, and IgG2b antibody responses, CD4+ and CD8+ T cell populations were found higher in the mice infected with P. berghei (ANKA) and challenged with T. gondii (ME49) compared to that in control mice infected with T. gondii alone (ME49). P. berghei (ANKA) + T. gondii (ME49) group showed significantly reduced the number and size of T. gondii (ME49) cysts in the brains of mice, resulting in lower body weight loss compared to ME49 control group. These results indicate that previous exposure to P. berghei (ANKA) induce resistance to subsequent T. gondii (ME49) infection.
Amino Acid Sequence ; Animals ; Antibody Formation ; Body Weight ; Brain ; Humans ; Immunoglobulin G ; Malaria ; Membranes ; Mice ; Parasites ; Plasmodium berghei ; Plasmodium ; Toxoplasma ; Toxoplasmosis

Based on the reactive oxygen species (ROS) regulatory properties of diphenyleneiodonium (DPI), we investigated the effects of DPI on host-infected T. gondii proliferation and determined specific concentration that inhibit the intracellular parasite growth but without severe toxic effect on human retinal pigment epithelial (ARPE-19) cells. As a result, it is observed that host superoxide, mitochondria superoxide and H2O2 levels can be increased by DPI, significantly, followed by suppression of T. gondii infection and proliferation. The involvement of ROS in anti-parasitic effect of DPI was confirmed by finding that DPI effect on T. gondii can be reversed by ROS scavengers, N-acetyl-L-cysteine and ascorbic acid. These results suggest that, in ARPE-19 cell, DPI can enhance host ROS generation to prevent T. gondii growth. Our study showed DPI is capable of suppressing T. gondii growth in host cells while minimizing the un-favorite side-effect to host cell. These results imply that DPI as a promising candidate material for novel drug development that can ameliorate toxoplasmosis based on ROS regulation.
Acetylcysteine ; Ascorbic Acid ; Humans ; Mitochondria ; Parasites ; Reactive Oxygen Species ; Retinaldehyde ; Superoxides ; Toxoplasma ; Toxoplasmosis

Toxoplasma gondii is an apicomplexan parasite that can cause toxoplasmosis in a wide range of warm-blooded animals including humans. In this study, we analyzed seroprevalence of T. gondii among 467 school children living in the rural areas of Pyin Oo Lwin and Naung Cho, Myanmar. The overall seroprevalence of T. gondii among school children was 23.5%; 22.5% of children were positive for T. gondii IgG, 0.4% of children were positive for T. gondii IgM, and 0.6% of children were positive for both T. gondii IgG and IgM. Geographical factors did not significantly affect the seroprevalence frequency between Pyin Oo Lwin and Naung Cho, Myanmar. No significant difference was found between males (22.2%) and females (25.0%). The overall seroprevalence among school children differed by ages (10 years old [13.6%], 11–12 years old [19.8%], 13–14 years old [24.6%], and 15–16 years old [28.0%]), however, the result was not significant. Polymerase chain reaction analysis for T. gondii B1 gene for IgG-positive and IgM-positive blood samples were negative, indicating no direct evidence of active infection. These results collectively suggest that T. gondii infection among school children in Myanmar was relatively high. Integrated and improved strategies including reinforced education on toxoplasmosis should be implemented to prevent and control T. gondii infection among school children in Myanmar.
Animals ; Child ; Education ; Female ; Humans ; Immunoglobulin G ; Immunoglobulin M ; Male ; Myanmar ; Parasites ; Polymerase Chain Reaction ; Seroepidemiologic Studies ; Toxoplasma ; Toxoplasmosis

Toxoplasma gondii infection induces parasite infiltration and apoptosis in the spleen. However, dose-dependent parasite infiltration, apoptosis, body weight alternations and survival in mice remain largely unknown. In this study, mice were intraperitoneally infected with 10, 30 or 100 tachyzoites of T. gondii, respectively. Parasite infiltration and apoptosis in the spleen were analyzed on days 3, 7, and 9 post-infection by immunohistochemistry and flow cytometry. Significantly higher levels of T. gondii infiltration and apoptosis in the spleen were found in 30 and 100 tachyzoites infected mice compared to 10 tachyzoites infected mice on days 7 and 9 post-infection. Although 30 and 100 tachyzoites infected mice showed significant body weight loss compared to 10 tachyzoites infected mice, all of the 100, 30, and 10 tachyzoites infected mice died by days 12, 15, and 17, each respectively. Interestingly, T. gondii infiltration in 10 tachyzoites infected mice were limited to capsule area of the spleen on day 9 post-infection. Several areas of parasite infiltrations were found in the 30 tachyzoites infected mice, where noticeable levels of splenic capsule de-adhesion occurred. These results indicated that parasite infiltration and apoptosis in the spleen, as well as body weight loss (survival) are closely correlated with infection dosage. The level of T. gondii infiltration and apoptosis in the spleen and splenic de-adhesion were dependent on the parasite dose.
Animals ; Apoptosis ; Body Weight ; Flow Cytometry ; Immunohistochemistry ; Mice ; Parasites ; Spleen ; Toxoplasma ; Toxoplasmosis