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PubMed1988

Prevention of peroral and congenital acquisition of Toxoplasma gondii by antibody and activated macrophages.

Intramuscular administration of Toxoplasma gondii lysate antigens to mice produced titers of T. gondii-specific antibody (measured by Sabin-Feldman dye test) greater than or equal to 1:1,024 in their sera. Intravenous administration of heat-killed Propionibacterium acnes to mice produced peritoneal macrophages with enhanced microbicidal capacity against T. gondii. Mice with high antibody titers or activated peritoneal macrophages or both had reduced numbers of Toxoplasma cysts in their brains 30 days after peroral challenge. Specific antibody and activated macrophages appeared to act together to significantly (P = 0.01) reduce the numbers of Toxoplasma cysts. A reduction in tissue infection as a result of these treatments was also demonstrated by subinoculation of brain tissue. A high antibody titer alone did not protect against congenital infection. Mice treated with P. acnes delivered reduced numbers of T. gondii-infected pups (P greater than 0.05). Treatment that produced high titers of Toxoplasma antibody and activated macrophages provided significant protection against congenital infection (P less than 0.05).

Administration, Oral↗

PubMed1983

Demonstration of intraocular synthesis of immunoglobulin G toxoplasma antibodies for specific diagnosis of toxoplasmic chorioretinitis by enzyme immunoassay.

By using a modified enzyme immunoassay we have conducted a detailed study on the intraocular synthesis of toxoplasma antibodies during ocular toxoplasmosis. In control patients operated on for cataracts, the ratio of immunoglobulin G (IgG) toxoplasma antibodies in serum to those in aqueous humor was more than 100. In eight of the nine patients with clinically diagnosed toxoplasmic chorioretinitis, the ratio ranged between 6 and 56. In five patients with some other type of uveitis, the ratio was comparable with that in controls. Parallel determinations of mumps IgG antibody ratios were carried out to prove that the increased intraocular toxoplasma antibody levels were not a result of increased diffusion or polyclonal antibody stimulation. In all patients, mumps antibody ratios were within normal range. We also tested the samples of aqueous humor for IgM and IgA antibodies, but the antibodies in the aqueous humor were found to be exclusively IgG. Our results indicate that IgG-class anti-toxoplasma antibodies are produced locally within the eye in cases of toxoplasmic chorioretinitis. The determination of these antibodies can offer a valuable aid to make a specific etiological diagnosis of ocular toxoplasmosis.

Adolescent↗

PubMed1995

Incidence of acute symptomatic toxoplasma retinochoroiditis in south London according to country of birth.

OBJECTIVE: To determine the incidence of acute symptomatic toxoplasma retinochoroiditis presenting to ophthalmologists for patients born in Britain and elsewhere. DESIGN: Population based, cross sectional study. SETTING: 11 districts in south Greater London. SUBJECTS: All patients presenting to NHS ophthalmologists with symptoms due to acute toxoplasma retinochoroiditis in 1992-3. MAIN OUTCOME MEASURE: Intraocular inflammation in association with a retinochoroidal scar, active adjoining retinitis, and IgG serum antibodies to toxoplasma. RESULTS: The estimated incidence of acute symptomatic retinochoroiditis for all people born in Britain was 0.4/100,000/year. If a mean of two symptomatic episodes per lifetime is assumed, 100 people born in Britain may be affected each year, about a fifth of the estimated 500-600 congenitally infected people born each year. CONCLUSIONS: A substantial proportion of people with acute symptomatic toxoplasma retinochoroiditis were born outside the country, and the number born in Britain was smaller than the number previously estimated to develop retinochoroidal lesions due to congenital toxoplasmosis. These findings suggest that prenatal screening for toxoplasmosis in Britain may be of limited benefit.

Acute Disease↗

PubMed2002

Two case reports of pituitary adenoma associated with Toxoplasma gondii infection.

The involvement of the pituitary in cases of toxoplasmosis has been described in the literature only rarely. This is the first report to describe pituitary adenoma in association with Toxoplasma gondii infection. The two patients were 43 and 19 year old women. Radiological examination revealed tumours in the sellar region. Microscopically, the tumours consisted of small homogeneous polygonal or round cells. Toxoplasma cysts were found among the tumour cells, a finding confirmed by Toxoplasma gondii specific antibody immunohistochemistry. The association between pituitary adenoma and toxoplasma raises the possibility that T gondii might be involved in the development of certain cases of pituitary adenoma.

Adenoma↗

PubMed2003

Seroprevalence of Toxoplasma gondii infection among veterinary staff in Ontario, Canada (2002): implications for teratogenic risk.

BACKGROUND: Toxoplasma gondii infection is embryotoxic in humans. It is mainly transmitted through raw/undercooked meat and ingestion of oocysts in cat feces. There remains controversy about the actual risk of cats transmitting the disease to humans. Our primary objective was to determine the seroprevalence of T. gondii antibody among veterinary staff, to ascertain whether they have an increased risk through occupational exposure. Our secondary objective was to examine their practices regarding cats, toxoplasma infection, and pregnancy. METHODS: Veterinary staff attending the 2002 Annual Ontario Veterinary Medical Association Conference were invited to discuss their toxoplasma seroprevalence. Interested attendees completed a questionnaire and a physician drew blood samples to determine T. gondii titres using the ELISA IgG test. RESULTS: We collected 161 completed questionnaires, and 141 blood samples. There were 20 (14.2%, CI 95%:8.4-19.9%) reactive titres among the veterinarian staff (80% females aged 30-45). All were regularly exposed to cats, washed their hands when in contact and few wore gloves routinely. CONCLUSIONS: These findings of low positive rates may be used to reassure veterinary staff that their exposure to cats does not appear to increase their risk of contracting toxoplasma infection and that pregnant women are not at an increased risk by owning a cat.

Animals↗

PubMed2005

Probable neuroimmunological link between Toxoplasma and cytomegalovirus infections and personality changes in the human host.

BACKGROUND: Recently, a negative association between Toxoplasma-infection and novelty seeking was reported. The authors suggested that changes of personality trait were caused by manipulation activity of the parasite, aimed at increasing the probability of transmission of the parasite from an intermediate to a definitive host. They also suggested that low novelty seeking indicated an increased level of the neurotransmitter dopamine in the brain of infected subjects, a phenomenon already observed in experimentally infected rodents. However, the changes in personality can also be just a byproduct of any neurotropic infection. Moreover, the association between a personality trait and the toxoplasmosis can even be caused by an independent correlation of both the probability of Toxoplasma-infection and the personality trait with the third factor, namely with the size of living place of a subject. To test these two alternative hypotheses, we studied the influence of another neurotropic pathogen, the cytomegalovirus, on the personality of infected subjects, and reanalyzed the original data after the effect of the potential confounder, the size of living place, was controlled. METHODS: In the case-control study, 533 conscripts were tested for toxoplasmosis and presence of anti-cytomegalovirus antibodies and their novelty seeking was examined with Cloninger's TCI questionnaire. Possible association between the two infections and TCI dimensions was analyzed. RESULTS: The decrease of novelty seeking is associated also with cytomegalovirus infection. After the size of living place was controlled, the effect of toxoplasmosis on novelty seeking increased. Significant difference in novelty seeking was observed only in the largest city, Prague. CONCLUSION: Toxoplasma and cytomegalovirus probably induce a decrease of novelty seeking. As the cytomegalovirus spreads in population by direct contact (not by predation as with Toxoplasma), the observed changes are the byproduct of brain infections rather than the result of manipulation activity of a parasite. Four independent lines of indirect evidence, namely direct measurement of neurotransmitter concentration in mice, the nature of behavioral changes in rodents, the nature of personality changes in humans, and the observed association between schizophrenia and toxoplasmosis, suggest that the changes of dopamine concentration in brain could play a role in behavioral changes of infected hosts.

Adult↗

PubMed1971

[Fine structure of Toxoplasma gondii]

The importance of Toxoplasma gondii in human disease stimulated a number of electron microscope studies on the structure of this protozoan parasite. Gustafson et al. first studied the fine structure by means of thin sections in 1954. Many other papers havs subsequantly appeared. It is well known that Toxoplasma gondii has two stages in its life cycle-the proliferative forms and the cyst. The purpose of the electron microscopical work reported here was to study the fine structure of Toxoplasma gondii with recent techniques clarifying the correlation between the proliferative forms and cyst. RH strain and KM strain as proliferative forms on the one hand and Beverley strain as a cyst form of Toxoplasma gondii on the other hand were used throughout this study. 1) The conoid, toxoneme, nucleus, nucleolus, osmiophilic granules, mitochondria and vacuoles were found in RH strain as wsll as in KM strain and Beverley strain. 2) The endoplasmic reticulum was found in the cytoplasm of RH strain and KM strain. It was better developed in KM strain than in RH strain. 3) The outside contour of the organism of Beverley strain was somewhat irregular and toxoneme of this organism was better developed than in the other two strains. 4) Vacuoles were found in RH strain, KM strain and Beverley strain. Furthermore, tube-like bodies were observed in the vacuoles of the organism of RH strain. 5) In KM strain, two organisms of the same size were demonstrated in the leucocytes. It was presumed that they were products of longitudinal division.

Journal Article↗

PubMed1980

Toxoplasma gondii in Costa Rican cats.

Toxoplasma gondii infection of cats was studied in seven localities in Costa Rica. A total of 237 cats were tested for antibody by the dye test, and for oocysts by injection into mice. Toxoplasma was isolated from 55 (23%) and antibody was found in 109 (46%). Sixty percent of cats were infected as shown by shedding or antibody. Of the 55 isolations, 64% were from kittens without antibody and 36% from kittens with antibody. Almost half of the Toxoplasma isolations were made from the feces of kittens weighing less than 600 g, 35 cm in length, or under 2 months of age, of which 41% were shedding Toxoplasma. Six hundred and seventy-six homeowners in the seven towns were questioned about the number of owned and stray cats visiting their houses, the cats' pattern of roaming, food sources, types of food foraged, defecation sites outdoors and indoors, and location of fecal deposits in houses. Seventy-six percent of houses reported cats, which averaged 2.1 cats per house; about 80% were strays, and 99% lived outdoors part or all of the time. The cats visited from 5-12 (average 6) houses, foraging for food in garbage, hunting mice, rats, sparrows and insects. Of the 516 households reporting cats, 29% supplied some food in addition. In 14% of these houses cats defecated in the house, including the false attic and crawl space; they commonly defecated in front and backyards of houses, close to human habitation and accessible to intermediate hosts.

Animals↗

PubMed1980

Intermediate and transport hosts of Toxoplasma gondii in Costa Rica.

Toxoplasma gondii was isolated from 3.5% of 202 Mus musculus, 12.5% of 120 Rattus norvegicus, 16% of 106 sparrows (Zonotrichia capensis), and from 54% of 50 chickens from Costa Rica. The infection rate in chickens increased from 23% in those weighing less than 500 g, to 73% in those between 500 and 1,000 g, indicating a rapid rate of acquiring infectin, probably from the soil in which they constantly search for food. No isolates were made from Musca domestica, or from four genera of roaches caught in the wild. However, Toxoplasma was isolated from four of 16 lots of earthworms. Most strains of Toxoplasma isolated from Costa Rican cats produced chronic latent infections in mice. However, even when infected with virulent strains, mice died at a time when numerous bradyzoites had been formed. Also, the availability of bradyzoites in chickens 8-10 days after ingestion of oocysts was comparable to that in mice. Therefore, several infected prey species are available as intermediate hosts to cats, providing the bradyzoites essential for the shedding of large numbers of oocysts. The isolation of Toxoplasma from earthworms or the soil associated with them illustrates their possible role as transport hosts to infect chickens and other birds feeding on them. The possible role of other transport hosts could not be confirmed.

Animals↗

PubMed2001

Toxoplasma encephalitis in HIV: case report.

In Tanzania, no data are available on the prevalence of brain infection by toxoplasma in HIV-infected patients. A case of a 35-year old man with fulminant toxoplasma encephalitis (TE) is reported for the first time. TE was not suspected clinically in our patient who presented with a one week history of severe headache and treated empirically with antimalarial drugs. TE was diagnosed postmortem histologically by haematoxylin-eosin and immunohistochemical stain with P30 antibody for toxoplasma antigen. The findings in our case support the suggestion that a high index of suspicion for TE should be maintained in HIV-infected patients presenting with focal neurological symptoms. The case highlights the importance of autopsy studies in not only documenting a toxoplasma brain lesion but also in increasing the awareness for its diagnosis in HIV-infected patients in Tanzania and other developing countries.

AIDS-Related Opportunistic Infections↗

PubMed1979

Probable transmission of Toxoplasma gondii by organ transplantation.

Two heart transplant recipients developed toxoplasmosis shortly after surgery. As neither recipient had serologic evidence of exposure to Toxoplasma gondii before transplantation, infection was acquired from an exogenous source. Of the possible modes of transmission of Toxoplasma to the recipients, infection by the oral route or through transfusion of blood or blood products seems remote. Since both heart donors had serologic evidence of recently acquired toxoplasma infection at the time of transplantation and the myocardium is known to be infected with the organism during acute infection, we considered these facts to be a strong implication that the donors' hearts were the most likely source of toxoplasma infection in the recipients.

Adult↗

PubMed1998

Toxoplasma antibody prevalence in Nepalese pregnant women and women with bad obstetric history.

Sera from randomly selected 345 pregnant Nepalese women aged 16-36 years and 13 women with bad obstetric history (BOH) were tested for the presence of Toxoplasma antibodies using microlatex agglutination (MLA) and ELISA methods. The overall prevalence was 55.4% (191/345). Prevalence was slightly higher (59.0%) in older age-group (27-36 years) compared with younger age-group (16-26 years) (52.2%). No significant difference in antibody prevalence in women belonging to two different ethnic-groups (Tibeto-Burmans 57.8%, Indo-Aryans 52.7%) was observed (p>0.05). MLA antibody titer ranged from 1:16 to 1:2,048. Over three-fourth of the women showed either high (1:510 or over) or low (1:16 or 1:32) antibody titer. Three percent (6/191) of MLA antibody positive subjects had Toxoplasma IgM antibodies by IgM-ELISA. All six IgM antibody positive pregnant women had MLA antibody titer of over 1:510. Of the total 13 women with BOH, 5 (38.5%) had Toxoplasma antibodies of which 2 (40.0%) were positive for Toxoplasma-IgM antibodies.

Adolescent↗

PubMed1999

Immunoblotting and enzyme linked-immunosorbent assay for diagnosis of toxoplasma infection in HIV Thai patients.

Toxoplasma gondii has been recognized as an important cause of morbidity and mortality among immunocompromised persons. The diagnosis of T. gondii infection is most often based on serological tests results. Serological diagnosis can be limited in AIDS patients because of depressed antibody responses. Fifty serum samples were used in this study to investigate serological evidence of toxoplasmosis in HIV positive Thai patients by Platelia kit, the commercial enzyme-linked immunosorbent assay (ELISA) in which the membrane protein p-30 is the predominant antigen and immunoblot technique (IB). Sera of HIV positive Thai patients with Toxoplasma infection recognized the same antigenic component, the 32 kDa antigenic band, as is recognized by Toxoplasma positive sera from immunocompetent patients and it may represent a specific marker for diagnosis of Toxoplasma infection in HIV positive Thai patients.

AIDS-Related Opportunistic Infections↗

PubMed1975

[Influence of toxoplasma infection on the course of pregnancy and child development. Results of a prospective study].

This report gives a survey of the statistical evaluation in the combined study of "The course of gravidity and development of the child" in connection with toxoplasma infection which is sponsored by the German Research Council (DFG). In respect to the collected data it is possible to summarize as follows: 1. Neither the anamnestic nor the data of the observed gravidities allow the construction of a relationship between toxoplasma infection of a mother and the child after eliminating disturbing factors, especially that of the age (Tabelle 1-4 and Fig. 1). 2. An effect of prophylactic sulphonamide treatment in cases of latent and acute infected women has never been observed. The low number of abortions in the group of treated women is misleading because pregnant women with early abortion never received any treatment, therefore these people are included under the untreated group. 3. Up till now we have not observed a case of connatal toxoplasma infection in nearly 5,000 new born babies. After eliminating unreliable reports, abnormal developments which are thought to be related to toxoplasma infections have never been observed.

Abortion, Spontaneous↗

PubMed1992

Studies on chronic liver diseases in patients with and without Toxoplasma latent infection.

Chronic liver diseases mainly due to schistosomiasis is a common clinical feature in Egypt. On the other hand, Toxoplasma latent infection is another common feature. In this paper, it was aimed to study the role of Toxoplasma latent infection in patients with chronic liver diseases mainly due to schistosomiasis. The latent Toxoplasma infection was measured by the positivity of IgG to ELISA and the negativity of IgM to DS-ELISA. The cellular immunity was assessed by the dinitrochlorobenzene (DNCB) skin test. The clinical and the laboratory studies showed that latent Toxoplasma infection had no marked effect on the progression of the chronic liver diseases.

Chronic Disease↗

PubMed2003

Toxoplasma infection in selected patients in Kathmandu, Nepal.

Seroprevalence of Toxoplasma infections in 272 patients with ocular diseases (uveitis, retinochoroiditis), malignancy (including leukemia), women with bad obstetric history (BOH) and others (patients with fever, lymphadenitis and encephalitis) have been was studied. Toxoplasma antibodies were detected by microlatex agglutination and IgM ELISA techniques. Overall, 50.7% (138/272) patients included in this study had Toxoplasma antibodies, out of which 5.7% (8/138) had IgM antibodies. Patients with malignancy had highest positive rate [68.7% (22/32)] followed by group of others. Of the different groups, women with BOH had highest Toxoplasma IgM positive rate [25.0%; (2/8)].

Animals↗

PubMed2003

Pathology of Toxoplasma myocarditis in acquired immunodeficiency syndrome.

Involvement of the myocardium by Toxoplasma gondii is seen in patients of acquired immunodeficiency syndrome (AIDS), mostly in association with toxoplasma encephalitis. Only few patients die as a direct result of cardiac dysfunction. Clinico-pathological findings of three cases of toxoplasma myocarditis are reported, one of which presented and died due to massive pericardial effusion. All cases showed diffuse myocarditis with parasites on histopathological examination. Incidence of toxoplasma myocarditis in patients dying with AIDS was 8.3% (3 out of 36 cases).

AIDS-Related Opportunistic Infections↗

PubMed1991

[Toxoplasma infection and endogenous uveitis].

The indirect fluorescent antibody technique was used to study the relationship between endogenous uveitis and toxoplasma infection. The seropositive rates of toxoplasma antibody in healthy people, farmers and patients with endogenous uveitis were 10.7%, 15.2% and 30.8% respectively. Compared with the healthy people, the infection rate in uveitic patients was significantly higher (P less than 0.01). The odds ratio of toxoplasma infection in endogenous uveitic patients was 3.72. The results suggest that toxoplasma infection is an infectious cause of endogenous uveitis.

Adolescent↗