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PubMed1987

Low prevalence of Toxoplasma infection in a Rocky Mountain prenatal population.

Congenital toxoplasmosis is rarely diagnosed in Colorado. To better determine whether this was the result of under-reporting or a valid observation, the sera of 120 consecutive prenatal patients from a lower-income clinic population were tested for antibodies to Toxoplasma gondii. Four of the patients had positive Sabin-Feldman dye tests, for a 3% incidence of past infection. None had immunoglobulin M (IgM) antibody. This rate is considerably lower than that in other populations, perhaps because the high-altitude, arid environment shortens oocyst survival in soil. A questionnaire designed to detect risk factors for Toxoplasma infection, such as exposure to cats or undercooked meat, did not indicate any differences between the antibody-positive and antibody-negative groups.

Adult↗
PubMed1985

An unexpected response to vaccination with a purified major membrane tachyzoite antigen (P30) of Toxoplasma gondii.

A purified Toxoplasma gondii tachyzoite membrane protein (P30) and a monoclonal antibody directed against this antigen were used to immunize mice. The P30 protein has an apparent m.w. of 30,000 and is the major radioiodinated tachyzoite membrane antigen identified by human and mouse antitoxoplasma antisera. Polyclonal and monoclonal antibody to the P30 antigen are parasiticidal in the presence of human serum. A series of mice were immunized with affinity column-purified P30 protein. This produced a dose-dependent, antigen-specific IgG and IgM response. The mice were challenged with the less virulent C strain tachyzoite. Immunized mice showed a statistically significant increase in mortality over nonimmunized control mice. In addition, vaccinated mice had an increased number of intracerebral tissue cysts when compared with the control group. Similar results were obtained with passive transfer immunization by using monoclonal antibody directed against the P30 antigen. Immunofluorescence assay of brain tissue cyst bradyzoites revealed a total absence of P30 antigen. Bradyzoites were also deficient in another major tachyzoite antigen of approximate m.w. 22,000 (P22). Mouse antibradyzoite serum absorbed with tachyzoites recognized bradyzoites but failed to identify tachyzoites. This suggests that there are stage-specific bradyzoite antigens of Toxoplasma gondii.

Animals↗
PubMed1985

Correlation of tissue infection and serologic findings in pigs fed Toxoplasma gondii oocysts.

Each of thirteen 6-week-old pigs was inoculated per os with 10,000 sporulated oocysts of Toxoplasma gondii. By postinoculation day (PID) 13, pigs were seropositive by the indirect fluorescent antibody test. Beginning on PID 13 and every 7 days thereafter through PID 97, 1 pig was killed and 6 tissues were examined for T gondii. Of the 13 pigs, 11 were infected, including the 1st pig killed on PID 13, although none of the pigs had gross lesions of toxoplasmosis. Tissues harboring T gondii most frequently were the heart and brain; organisms were detected less frequently in the longissimus muscles, diaphragm, and liver. Toxoplasma gondii was not detected in the bronchial lymph nodes. There was good correlation between antibody and presence of T gondii in these pigs. One additional pig, maintained as a noninfected control, remained seronegative and had no evidence of infection when killed on PID 97.

Animals↗
PubMed1985

Lymphocyte anergy specific to Toxoplasma gondii antigens in a baby with congenital toxoplasmosis.

A baby's clinical course during her first year of life documented her congenital infection with Toxoplasma gondii. Certain of her peripheral blood lymphocyte subtype numbers and functions were studied at intervals during this year: This patient's lymphocytes did not respond to Toxoplasma gondii antigens when she was 2 or 6 months old but did respond when she was 1 year old. Her lymphocyte anergy appeared to be a specific impairment or delay in lymphocyte blastogenic response to T. gondii antigens as her peripheral blood lymphocytes responded normally to the T-cell mitogen Concanavalin A and to allogeneic lymphocytes in mixed lymphocyte cultures. She had normal numbers of total peripheral blood lymphocytes and normal proportions of peripheral blood T cells with T4 and T8 surface antigens.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1985

A solid phase immunoassay (DIG-ELISA) as a serodiagnostic tool in bovine and porcine Toxoplasma gondii infection.

The diffusion-in-gel enzyme-linked immunosorbent assay (DIG-ELISA) was compared with the indirect immunofluorescent antibody test (IFAT) and with conventional ELISA for the detection of antibodies to Toxoplasma gondii in three experimentally infected calves and in 100 naturally infected swine. Good agreement was observed between the results obtained with DIG-ELISA and those from IFAT or ELISA. It was noted that in early experimental infection of calves, the IFAT recorded higher antibody levels than did DIG-ELISA, thus reflecting the differences in antigens used for the two methods. The DIG-ELISA, being technically simple and inexpensive and having a large capacity, was found to be well suited for screening purposes with regard to Toxoplasma antibodies.

Animals↗
PubMed1986

Secretory IgA specific for Toxoplasma gondii.

Secretory IgA specific for Toxoplasma gondii was identified in intestinal secretions of mice infected perorally with bradyzoites (encysted in brain) of the Me49 strain of T. gondii by using immunofluorescence microscopy and an ELISA. This activity was absorbed with tachyzoites of T. gondii but not mouse brain. To determine whether increased total amount of intestinal IgA might cause a nonspecific reaction in the ELISA for T. gondii-specific IgA, mice were immunized perorally with cholera toxin. This immunization produced intestinal IgA antibody to cholera toxin and increased the total amount of intestinal IgA, but there was no reactivity of intestinal secretions in the ELISA for T. gondii-specific IgA. Experiments in which ELISA were performed with monoclonal IgA, IgG, or IgM and antisera to IgA, IgG, or IgM demonstrated that the ELISA was specific for each Ig class. In addition, monoclonal IgA competed with the anti-Toxoplasma IgA activity of intestinal secretions obtained from mice infected with T. gondii.

Administration, Oral↗
PubMed1985

Preservation of laboratory strains of Toxoplasma gondii in vitro.

A procedure to obtain viable stabilates of virulent laboratory strains of Toxoplasma gondii with a prolonged storage life is described. Viable endozoites recovered from the sediment of mouse exudate or tissue cultures (LEP, HeLa) are suspended in Eagle's MEM medium supplemented with 10% calf serum and 10% dimethylsulfoxide and sealed into glass ampoules of 1-2 ml in volume. The ampoules are placed in an apparatus for gradual cell freezing, frozen to --35 degrees C at a rate of --1 degree C/min, and stored in liquid nitrogen. Reinoculation experiments on mice given the suspension intraperitoneally confirmed that such Toxoplasma gondii strains retain viability for at least 4 years. This in vitro preservation technique is compared with the analogous T. gondii preservation procedures described in the literature.

Animals↗
PubMed1985

Tissue culture isolation of Toxoplasma from blood of a patient with AIDS.

A man with acquired immunodeficiency syndrome and multiple opportunistic infections developed central nervous system signs, and results of computed tomography suggested brain abscess. Histologic study and culture of material obtained from the brain biopsy specimen revealed Aspergillus. The clot from a peripheral venous blood sample obtained at the time of biopsy was processed and cultured on a monolayer of L cells. Five days later, Toxoplasma tachyzoites were identified in the cell culture. We bring this case to the attention of the medical community to point out that inoculation of tissue cell cultures as for viral isolation may aid in the diagnosis of Toxoplasma infection in these and other immunocompromised patients.

Acquired Immunodeficiency Syndrome↗
PubMed1985

Role of lymphocyte blastogenesis to Toxoplasma gondii antigens in containment of chronic, latent T. gondii infection in humans.

Lymphocyte blastogenic transformation in response to Toxoplasma lysate antigen was markedly impaired in six of eight patients with chronic, latent Toxoplasma gondii infection and treated Hodgkin's disease. None of these patients with serum antibody to T. gondii measured by the Sabin Feldman Dye test and impaired lymphocyte transformation to T. gondii antigens had clinical or serologic evidence of disseminated, active infection with T. gondii. Partial depletion of adherent mononuclear leukocytes improved the impaired lymphocyte transformation of three of six patients; treatment of cultures from all patients with indomethacin improved their blastogenic transformation but culture with normal heterologous serum did not. These studies indicate that lymphocyte blastogenic response to T. gondii antigens is impaired in some patients with chronic, latent T. gondii infection and treated Hodgkin's disease but that this impairment of lymphocyte function is not sufficient to cause reactivation of chronic, latent T. gondii infection.

Adult↗
PubMed1985

Toxoplasma seroprevalence in animals in northern India.

In a serological survey of latent Toxoplasma prevalence on 3761 animals in northern India by the microtitre indirect haemagglutination test, 23.7 per cent were found to have antibody titres ranging from 1:4 to 1:1024. Seropositivity was recorded in 25.3 per cent of 1227 sheep, 30.3 per cent of 961 goats, 11.8 per cent of 603 horses, 19.3 per cent of 243 cattle, 15.7 per cent of 108 water buffaloes, 31.5 per cent of 178 pigs, 30.9 per cent of 175 dogs, 33.7 per cent of 80 cats and in 9.7 per cent of 186 bandicoot rats. Relevant epidemiological data has been furnished. High seropositivity in food animals and frequent isolations of Toxoplasma highlight the likely public health implications of the findings.

Age Factors↗
PubMed1979

Studies on antibody levels to Brucella abortus, Toxoplasma gondii and Leptospira serogroups in sera collected by the National Serum Bank during 1974-1976.

The New Zealand National Serum Bank is a collection of human sera consisting predominantly of specimens taken from healthy New Zealand blood donors. The studies presented here were designed to assess the antibody levels in two urban centres to Brucella abortus, Toxoplasma gondii and several Leptospiral serogroups including all those found in New Zealand. In none of the sera could complement fixing leptospiral antibodies be detected. There was evidence of low level immunity to both Toxoplasma gondii and Brucella abortus.

Adult↗
PubMed1979

Toxoplasma antibodies in ophthalmological patients.

Sera of 532 patients suffering from different ophthalmological diseases were studied for the presence of toxoplasma antibodies. Complement fixation test was positive in 44.9% of the patients. As compared with the 26.8% positivity rate determined earlier in the normal population the seropositivity in eye-patients was significantly higher. The highest incidence, 50%, was found in the age group of 21--30 years. In diseases with a confirmed aetiological role of toxoplasmosis, the incidence of seropositivity was higher than in the total material. This suggests that Toxoplasma gondii may have had a role in part of the diseases of the patients studied.

Adolescent↗
PubMed1979

Ultrastructural changes in mouse peritoneal exudate cells during infection with Toxoplasma gondii.

Infections of mouse peritoneal exudate cells with trophozoites of Toxoplasma gondii (BK strain) were studied by means of electron microscopy. After i.p. injection of Toxoplasma-trophozoites macrophages, lymphocytes, neutrophilic and eosinophilic granulocytes migrate into the peritoneal cavity of mice. All these cells can be parasitized by T. gondii. Multiplication of phagocytosed trophozoites is not inhibited, but obviously the infected cells favour their growth.

Animals↗
PubMedDate not supplied

[Anti-toxoplasma antibody titers and immunoglobulins].

285 sera from parturient patients have been tested for the presence of anti-toxoplasma antibodies by the direct Agglutination test and for Immunoglobulins by the immunochemical turbidimetric determination. 17 sera showed a significant increase in the titre of anti-toxoplasma antibodies; 5 of these 17 presented a simultaneous IgM level increase, subsequently confirmed by a 2 Mercaptoethanol pretreatment, this fact suggesting the presence of active infectious disease. The authors think it can be useful in the diagnostic assessment of active toxoplasmic infectious disease the simultaneous screening of sera by the two described methods: the direct Agglutination test and the immunochemical turbidimetric determination.

Agglutination Tests↗
PubMed1977

Experimental infection of bovines with oocysts of Toxoplasma gondii.

Calves aged 3 months were readily infected with oocysts and cysts of Toxoplasma gondii administered by oral route. Fever, respiratory distress, nasal discharge and hyperemia of the conjunctivas were the most significant clinical signs noted in the infected animals. Parasitemia was demonstrated in all infected calves. It occurred on different days and up to 62 days after the infection. Toxoplasma was demonstrated in tissues of all infected calves, and the organ most frequently parasitized was the lymph node. Parasitism of the retina was demonstrated in two calves. All infected animals had antibody against T. gondii in their serum. The Sabin-Feldman dye test and the indirect immunofluorescent test were both useful in detecting antitoxoplasma antibody.

Animals↗
PubMed1977

Survey of Toxoplasma antibodies among sheep in western United States.

A survey was conducted to determine the prevalence of toxoplasma antibodies among breeding ewes and among lambs slaughtered for food in western United States. Each serum was tested by the indirect hemaglutination method, using microtiter technique. Agglutination (greater than or equal to 2 +) at the 1:64 dilution was considered to be a positive reaction. Of 2,164 ewes from 18 flocks tested in California, 523 (24%) were seropositive for Toxoplasma gondii, with prevalence rates among flocks ranging from 4 to 51%. In 9 of those flocks, 1,495 ewes were stratified by whether ewes had lambed or were barren. On an overall basis, the antibody prevalence was similar (about 25%) in both groups, but there was a significant difference (P less than 0.05) in 1 flock in which 30% of the nursing ewes were seropositive, compared with 21% of the barren ewes. Of 1,056 market lambs from 19 lots tested, 85 (8%) were seropositive. The antibody prevalence in lambs tested at slaughter in California, by state of origin, were: Oregon, 11/51 (22%); Nevada, 32/159 (20%); Idaho, 12/147 (5%), and California, 30/699 (4%).

Abortion, Veterinary↗
PubMed1983

Antigenic differences between endozoites and cystozoites of Toxoplasma gondii.

Antigenic differences between the cystozoite and endozoite of Toxoplasma gondii were found using fluorescent antibody staining. Antisera against the cystozoite reacted against only the cystozoite, whereas antisera against the endozoite reacted against both endozoite and cystozoite. Absorption of sera with endozoites removed only positive reactions with endozoites. These findings are the first to suggest antigenic differences between these two forms of Toxoplasma.

Animals↗