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PubMed1991

[Several results of a Toxoplasma survey].

A pilot Toxoplasma survey was conduct in Ciego de Avila province during the month of September, 1985, to assess, in practice, the methodologic structure proposed for the National Toxoplasma Survey. Of the 292 listed individuals, 284 were surveyed during the field work phase (97.2%) and the remaining 2.8% of no response was due mainly to the fact that dwellers were not at home during the visit. The best day for this type of survey resulted to be Sunday, in the morning. No difficulty was noted with the used modelling, and results obtained in the application of used techniques and procedures are appropriate for use in the National Toxoplasma Survey. The prevalence rate of anti- Toxoplasma antibodies was 55.9%. There was a significant association between some risk factors such as: living with cats, ingestion of non potable water and ingestion of raw meat.

Cuba↗

PubMed1988

Toxoplasma peritonitis in a patient with acquired immunodeficiency syndrome.

Toxoplasma gondii was identified in a stained slide preparation of, and isolated from, peritoneal fluid specimens obtained from a patient with the acquired immunodeficiency syndrome (AIDS). At the time of admission to the hospital, the patient's serologic tests were positive for Toxoplasma. Toxoplasma was isolated from samples of the patient's blood by mouse inoculation. Findings of newly developed methods for diagnosis of the presence of T gondii in body fluids by assay for Toxoplasma-specific antigen and by use of a DNA probe were positive.

Acquired Immunodeficiency Syndrome↗

PubMed1986

Distribution of Toxoplasma gondii tissue cysts in commercial cuts of pork.

Distribution of Toxoplasma gondii cysts in tissues used for human consumption was studied in 4 naturally infected pigs (acquired infections) and in 2 experimentally infected pigs. On the day of euthanasia, pigs with acquired toxoplasmosis had serum antibody titers of 160 to 1,280 against T gondii (modified agglutination test). Experimentally infected pigs were inoculated with 10,000 oocysts of the GT-1 strain of T gondii and were euthanatized 267 or 357 days after inoculation. On the day of euthanasia, the experimentally infected pigs had serum antibody titers of 16 and 32 against T gondii. Fifty- to 100-g specimens from each of 6 cuts of meat commercially used to prepare Boston butt, arm picnic, ham, tenderloin, spareribs, and bacon and from the tongue, heart, brain, liver, kidneys, and diaphragm were collected from each pig and were digested in acid pepsin solution. Washed sediment from the digest of each specimen was inoculated SC into mice (6 mice/organ). Toxoplasma gondii was isolated from tissues of the 4 pigs with acquired toxoplasmosis; T gondii was isolated from the arm picnic, Boston butt, and tongue of 3 pigs, from the ham, tenderloin, spareribs, diaphragm and heart of 2 pigs, and from the bacon and brain of 1 pig. Toxoplasma gondii was not isolated from the kidneys of the 4 pigs with acquired toxoplasmosis. Toxoplasma gondii was isolated from the arm picnic, Boston butt, ham, spareribs, bacon, tongue, diaphragm, heart, and brain of the 2 experimentally infected pigs, and from the kidneys of one of the experimentally infected pigs.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1979

[Transmission of toxoplasma oocysts from domestic cats to rabbits (author's transl)].

The importance of the role of toxoplasma oocysts in the mode of spread of the infection for men and animal has differently been estimated. In own earlier experiments, we found out that the transmission of the infection by means of oocysts from cat to cat is not the rule. In a similar experimental setup, we tested now whether rabbits can be infected by getting into contact with faeces of cats containing sporulated toxoplasma oocysts (see table 1). 8 toxoplasma-free rabbits and two toxoplasma-free cats as control were placed on infectious faeces of 10 cats (group 1-8). As further controls served four non-infected rabbits being kept in the same cage (group 11-12). Four of eight rabbits which had been placed on the infectious faeces and one control animal having had no intended contact with those faeces got infected. Our experiments show that the question whether domestic cats have any significance as source of infection with toxoplasms cannot generally be answered. It has to be differentiated each time which mammal gets into contact with oocysts.

Animals↗

PubMed1981

Behavioral alterations caused by parasitic infection in case of latent toxoplasma infection.

In order to assess the effects of a latent Toxoplasma infection on behaviour and learning capacity, maze experiments with rats and mice were performed. The learning performance of rats and especially of mice was impaired, the memory of mice and their overall activity were reduced by infection. Theses results are supported by Hutchinson who also found that the activity of mice was reduced by Toxoplasma infection, and that they were less responsive to novel stimuli. These results indicate that Toxoplasma infection probably affects the animal's response to its environment, and the stimulation arising from it, and may even affect endogenous regulatory processes in the brain. Similar observations in humans suggest that an acquired Toxoplasma infection without giving rise to disease may have similar effects in man. These observations touch the general problem of the influence of parasitic infections on the CNS.

Animals↗

PubMed1995

[Pseudo-tumoral cystitis due to Toxoplasma in an patient with AIDS].

The authors report a case of cystitis due to Toxoplasma Gondii infection in a patient suffering from AIDS. Initial symptoms consisted of dysuria, extreme frequency and urgent micturition responsible for pseudo urinary incontinence. Urine culture was sterile. Pelvic computed tomography and pelvic MRI demonstrated thickening of the bladder wall and seminal vesicles. Cystoscopy confirmed the presence of an intravesical proliferation with a pseudoneoplastic appearance. The diagnosis of Toxoplasma cystitis was confirmed by the discovery of Toxoplasma cysts on histological examination of bladder biopsies. Toxoplasma cystitis is a rare cause of pseudoneoplastic bullous cystitis in HIV-seropositive patients.

AIDS-Related Opportunistic Infections↗

PubMed1993

Persistence of tissue cysts in edible tissues of cattle fed Toxoplasma gondii oocysts.

Four 1-year-old steers were each inoculated orally with 10,000 Toxoplasma gondii oocysts of the GT-1 strain and euthanatized on postinoculation days (PID) 350, 539, 1191, and 1201. Samples (500 g) of tongue, heart, semimembranosus and semitendinosus muscles (roast), intercostal muscles (ribs), longismus muscles (tenderloin), brain, kidneys, liver, and small intestine were bioassayed for T gondii by feeding to cats and examination of cat feces for shedding of oocysts. Toxoplasma gondii was recovered by bioassays in cats for the 3 steers necropsied PID 350, 539, and 1191, but not from the steer euthanatized on PID 1201. Cats shed oocysts after ingesting tongue from 2 steers, heart from 3 steers, liver from 2 steers, and roast, ribs, brain, and intestines from 1 steer each. Toxoplasma gondii was not isolated from any of the other bovine tissues. In addition to tissues bioassayed in cats, homogenates of mesenteric lymph nodes, lungs, spinal cord, spleen, and eyes were bioassayed in mice for T gondii infection. Toxoplasma gondii was not recovered from the 135 mice inoculated with tissue from each of the 4 steers. All 4 inoculated steers developed high T gondii antibody titers (> or = 1:8,000) in the agglutination test, using formalin-fixed whole tachyzoites. In the steer euthanatized on PID 1201, agglutinating T gondii antibody titers decreased from 1:4,000 to 1:320 between 2 and 5 months after inoculation and to 1:20 by 19 months after inoculation.

Agglutination Tests↗

PubMed1996

The prevalence of toxoplasma antibodies in pregnant Nigerian women and the occurrence of stillbirth and congenital malformation.

Toxoplasma antibody serological tests were carried out using the Dye test on sera of pregnant and postpartum Nigerian women to investigate whether there was any association between the levels of antibody titres and the occurrence of stillbirths and congenital malformations. There was a high prevalence of toxoplasma antibodies in the sera of both pregnant and postpartum women. The prevalence rates for the pregnant women ranged from 72.5% to 88.8% with an overall rate of 75.4%; whilst for the postpartum women, the prevalence rates ranged from 75.0% to 94.4% with an overall rate of 80.5%. The toxoplasma antibody titres of the sera from the live-born babies as well as stillbirths and congenitally malformed babies ranged from 1:16 to 1:1024. The exact role played by toxoplasma in the occurrence of stillbirths and congenital malformation in our area of study is, however, not clear. For future research, it is suggested that larger samples be studied in order to enhance the validity of the findings of the present study.

Adolescent↗

PubMed1997

The effect of drugs on the mortality of mice inoculated with Friend leukaemia virus or toxoplasma gondii.

Infection and tumors provoke substantial changes accompanied with the disbalance of many neuroendocrine factors which in their summarizing effects influence the life span of animals. Our previous results showed enhanced mortality after one injection of morphine in association with Friend leukaemia virus infection. The aim of this study was to examine the effects of some other opioids (pethidine and pentazocine) and an acetylcholine esterase inhibitor neostigmine on the survival of animals under two conditions: (1) Friend leukaemia virus infection which mostly depressed immune functions, and (2) Toxoplasma gondii infection which in general enhanced the immune status. In contrast to our previous observation with morphine, the mortality induced by single doses of pethidine (150 mg/kg) or pentazocine (50-75 mg/kg) was unchanged during the Friend leukaemia virus infection. A single injection of neostigmine (0.42 or 0.56 mg/kg) was significantly more lethal in DBA-2 mice infected with Friend leukaemia virus. Neostigmine in doses of 0.33 and 0.4 mg/kg caused death in 46 % and 57 %, respectively, of animals infected with Toxoplasma gondii which was significantly higher in comparison with only 8 % and 12.5 % in control groups. Pethidine (150 mg/kg) killed 70 % of Toxoplasma gondii infected animals and even 90 % of non-infected mice. Thus, the Friend leukaemia virus and Toxoplasma gondii infections increased toxicity only of some drugs which may, at least partly, be associated with altered immune status during infection and involvement of the cholinergic system.

Acetylcholine↗

PubMed1998

[Seroepidemiology of Toxoplasma gondii infection among Atayal aborigines and local animals in Nan-ao district, Ilan county and Jen-ai district, Nan-tou county, Taiwan].

In this study, latex agglutination test (LAT) was used to detect sera anti-toxoplasma antibodies of Atayal aborigines and local animals in Nan-ao district, Ilan county and Jen-ai district, Nan-tou county as a measure of exposure to the Toxoplasma gondii. Out of 422 Atayal aborigines and 64 different animals were tested in Nan-ao district and 82 Atayal children in Jen-ai district were also screened, the positive rates for sera anti-toxoplasma antibodies were 21.8%, 17.2% and 15.9%, respectively. In Nan-ao district, neither were the positive rates significantly different in males (22.1%) and females (21.4%), nor in humans (21.8%) and dogs (19.6%) (P > 0.05). The seroprevalence in adults (28.3%) was significantly higher than that in children (18.7%) (P < 0.05), and the highest seropositive rate (38.1%) was in the age group 50-59 years and the lowest (7.7%) was in the age group 1-9 years. In general, the age pattern of prevalence is consistent with increasing duration of exposure to Toxoplasma gondii with age. For animals, the seropositive rate in dogs (19.6%) was also significantly higher than that in wild rats (7.7%) (P < 0.05). No significant difference in seropositive rate of Atayal children was observed between Nan-ao and Jen-ai districts (P > 0.05).

Adolescent↗

PubMed1965

INDIRECT FLUORESCENT ANTIBODY TECHNIQUE IN THE SEROLOGY OF TOXOPLASMA GONDII.

The indirect fluorescent antibody technique has been used to titrate patients' antibody against Toxoplasma gondii. Rigorous tests of the immunological validity of the method were made. The reactions of the gamma globulin of human immune serum with Toxoplasma gondii and fluorescent rabbit anti-human gamma globulin were thus shown to be specific. Thereafter the technique could be used with confidence to detect the reaction between doubling dilutions of patient's serum and smears of unfixed Toxoplasma gondii. In this way, titres were obtained with the indirect fluorescent antibody technique which agreed well with those of the dye test at both low and high levels of antibody. Compared with the dye test, the indirect fluorescent antibody technique has many advantages. The end-point is sharp and obviates the counting of stained and unstained organisms; supplies of antibody-free accessory factor sera are not needed; prozones undetected by the dye test are strongly positive at screening dilutions, the reagents keep indefinitely and lend themselves to preparation, standardization, and issue by a central reference laboratory.

Animals↗

PubMed1993

Toxoplasma gondii: induction of toxoplasmic encephalitis in mice with chronic infection by inoculation of a murine leukemia virus inducing immunodeficiency.

Infection with the avirulent Fukaya strain of Toxoplasma gondii induced few inflammatory responses in the brain of C57BL/6 mice. When mice with chronic infection with the Fukaya strain were challenged with murine leukemia virus (MuLV) LP-BM5, which is known to induce a remarkable immunodeficiency in mice, those mice suffered from a severe encephalitis. Infiltration of mononuclear cells was remarkable in both meninges and parenchyma in those mice. Numerous sites of acute focal inflammation were noted in the brain and the presence of tachyzoites and Toxoplasma antigens was demonstrable in those areas by immunoperoxidase staining using rabbit anti-Toxoplasma IgG antibodies. All mice infected with both T. gondii and LP-BM5 MuLV died from 9 to 14 weeks after the virus infection, whereas no mice died in the infection with either T. gondii or the virus alone. Spleen cells from the mice with coinfection failed to respond to both T cell (Con A) and B cell mitogens (LPS) in vitro in contrast to the cells from mice infected with T. gondii alone that responded to those mitogens just as cells from normal mice did. Mice chronically infected with T. gondii and challenged with LP-BM5 MuLV appears to provide a good animal model of toxoplasmic encephalitis which is a major cause of morbidity and mortality in AIDS patients.

Animals↗

PubMed1996

Toxoplasma gondii: structure and characterization of the 26S ribosomal RNA and peptidyl transferase domain.

The 26S, 5.8S, and the intergenic spacer ribosomal DNAs (rDNA) of Toxoplasma gondii have been cloned and completely sequenced from both DNA strands. The length of the large subunit was found to be 3487 nucleotides and the 5.8S was 153 nucleotides long. These formed the large rRNA subunit of Toxoplasma and were mapped in the rDNA unit known to be repeated 110 times in a head-to-tail fashion in the genome. Primer extension analysis and multiple alignments localized the 5' end point of the two rRNAs. Comparisons with Toxoplasma rDNA by nucleic acid homology studies gave 76% similarity with the dinoflagellate Prorocentrum micans, 66% with yeast Saccharomyces cerevisiae, and 64% with the ciliate Tetrahymena thermophila. Similarity was apparent in the conserved core structure of the large subunit rRNA and divergent sequences were identified in the so-called divergent domains. Construction of a secondary structure model of the peptidyl transferase center of the large rRNA revealed similarities with the same domain from other life forms.

Animals↗

PubMed1997

A novel class of unconventional myosins from Toxoplasma gondii.

Here, we describe the complete deduced amino acid sequence of three unconventional myosins identified in the protozoan parasite Toxoplasma gondii. Phylogenetic analysis reveals that the three myosins represent a novel, highly-divergent class addition to the myosin superfamily. Toxoplasma gondii myosin-A (TgM-A) is a remarkably small approximately 93 kDa myosin that shows a striking departure from typical myosin heavy chain structure in having a head and tail domain but no discernible neck domain. In other myosins, the neck is defined by one or more IQ motifs that serve as potential light chain binding domains. No IQ motifs are apparent in TgM-A. The tail domain of TgM-A encompasses only 57 amino acid residues and is characterized by its highly basic charge (pI = 10.8). The other two Toxoplasma myosins, TgM-B and TgM-C appear to be the product of differential RNA splicing with TgM-B yielding a protein of approximately 114 kDa and TgM-C a protein of approximately 125 kDa. These two myosins are identical throughout their head domain and neck domain which contains a single IQ motif. TgM-B and C share the proximal 245 residues of their tail domain and then diverge in their tail structure distally. The tails, like that of TgM-A, share no homology to any other myosin tails apart from a highly basic charge. The identification of yet another class of unconventional myosins, including a myosin as novel in structure as the 93 kDa TgM-A, continues to underscore the diversity of this family of molecular motors.

Amino Acid Sequence↗

PubMed2001

High-level expression and purification of immunogenic recombinant SAG1 (P30) of Toxoplasma gondii in Escherichia coli.

Surface antigen 1 (SAG1) of Toxoplasma gondii is a good candidate for diagnosis and vaccine development, but recombinant SAG1 produced in Escheichia coli often loses its specific immunogenicity due to the incorrect folding. In the present study, a truncated SAG1 was highly expressed in E. coli as a fusion protein, about 30% of the total protein of the cell lysate. After a simple purification and refolding procedure, purified rSAG1 can be recognized by human Toxoplasma-infective serum, and ELISA kits constructed by rSAG1 can sensitively and specifically detect toxoplasma infection.

Animals↗

PubMed2003

The mechanism of interferon-gamma induced anti Toxoplasma gondii by indoleamine 2,3-dioxygenase and/or inducible nitric oxide synthase vary among tissues.

L-Tryptophan degradation by indoleamine 2,3-dioxygenase (IDO) induction and reactive nitrogen intermediates produced by inducible nitric oxide synthase (iNOS) induction are important factors for IFN-gamma-induced anti-toxoplasma activities. In the present study, the effects of acute Toxoplasma gondii (T. gondii) infection on IDO and iNOS were investigated using wild-type (WT) and IFN-gamma gene-deficient (IFN-gamma KO) mice. In the WT C57BL/6J mice, enzyme activities and mRNA levels of IDO in both lung and brain were markedly increased, and lung L-tryptophan concentrations were dramatically decreased following infection. In contrast, these metabolic changes did not occur in infected IFN-gamma KO mice. The level of iNOS induction in the infected IFN-gamma KO mice was high in lung and low in brain compared to that in infected WT mice. The extent of increased mRNA expression of T. gondii surface antigen gene 2 (SAG2) in lung and brain induced by infection was significantly enhanced in the IFN-gamma KO mice compared to that in WT mice. Treatment with N-nitro-L-arginine methyl ester, an iNOS inhibitor, increased the levels of SAG2 mRNA in brain, but not in lung following infection. This in vivo study provides evidence that L-tryptophan depletion caused by T. gondii is directly mediated by IFN-gamma in the lung, where iNOS is not induced by IFN-gamma. This study suggests that there is an anti-toxoplasma mechanism of cross-regulation between iNOS and IDO and that the expression of main anti-parasite effector mechanisms of iNOS and/or IDO may vary among tissues.

Animals↗

PubMed1991

High risk of developing toxoplasmic encephalitis in AIDS patients seropositive to Toxoplasma gondii.

We studied 41 AIDS patients in the Austrian Tyrol with respect to toxoplasma antibody titers and the presence of CNS toxoplasmosis. In no patient had primary Pneumocystis carinii pneumonia (PcP) prophylaxis with either trimethoprim/sulfamethoxazole or pyrimethamine/sulfadoxine been applied; the degree to which CNS toxoplasmosis is influenced by this kind of PcP chemoprophylaxis, widely used elsewhere, is still unclear. In this study 47.4% of toxoplasma-seropositive patients developed CNS toxoplasmosis, compared to the previously estimated risk of 12%-28% for developing CNS involvement in such patients. In view of the high risk of toxoplasma-seropositive patients with AIDS, increased efforts in developing a well-tolerated chemoprophylaxis to combat CNS toxoplasmosis are required.

Acquired Immunodeficiency Syndrome↗

PubMed1976

Effects of immune lymphocyte products and serum antibody on the multiplication of Toxoplasma in murine peritoneal macrophages.

In vitro studies on cell-mediated immunity against Toxoplasma infection were carried out by estimating the ability of antigenically stimulated lymphocytes. Splenic lymphocytes from normal mice and from hyper-immunized mice were cultured in the presence or absence of Toxoplasma lysate antigen. The cell-free supernatant fluids from the lymphocyte cultures were assassed for their ability to alter the functional capacities of normal macrophages. When glycogen-induced peritoneal macrophages were incubated with the culture supernatant from immune lymphocytes reacting with specific angigen, the intracellular multiplication of the organisms was inhibited remarkably. In contrast, the addition of antitoxoplasma antibody to culture medium had no effect on the enhancement of phagocytic activity of culture macrophages. However, when extra-cellular organisms were exposed to fresh or heat-inactivated immune serum just before infection of the monolayers, the intracellular multiplication of Toxoplasmas was inhibited significantly by either activated or normal macrophages.

Animals↗