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Detection of Toxoplasma cysts and oocysts in an urban environment in a developed country.

Feces of 115 stray or unwanted cats were screened for Toxoplasma oocysts by sucrose density centrifugation and inoculation into mice. None of the feces examined contained detectable levels of viable oocysts. Using a laboratory infected cat, the sensitivity of this detection technique was found to be about 250 oocysts/g of feces by microscopic analysis and about 2 oocysts by mouse inoculation. Samples of pork and lamb chops bought from suburban butcher shops were screened for Toxoplasma cysts by pepsin digestion and mouse inoculation. One of the 30 pork and none of the 30 lamb chops contained viable cysts. Experimental studies determined that the sensitivity of this method of detection was about 1 cyst/100 g of tissue. The relative likelihood of each route of Toxoplasma infection for members of an urban community in a developed country is discussed.

Animals↗

[Toxoplasma antibodies by indirect latex agglutination tests in St. Mary's Hospital patients]

A total of 421 patients hospitalized in St. Mary's Hospital were examined by indirect latex agglutination test in order to evaluate the Toxoplasma antibody in Korean from June to August 1981. The test sera of the patients were obtained from each age group by random sampling. 1. The 421 samples of test sera showed negative in 153, 1:2 in 157, 1:4 in 59, 1:8 in 27, 1:16 in 7, 1:32 in 9, 1:64 in 2, 1:128 in 4 and 1:256 in 3 cases, respectively. 2. The positive rate of Toxoplasma antibody was 4.3 percent in this sample when indirect latex antibodies of 1:32 or higher were regarded as positive. 3. The titers of positive Toxoplasma antibodies were increased by age.

Journal Article↗

Primary and reactivated toxoplasma infection in patients with cardiac transplants. Clinical spectrum and problems in diagnosis in a defined population.

We have attempted to define the serologic criteria for diagnosis of toxoplasmosis in heart transplant recipients. Of 31 patients who were seronegative before transplantation, 4 received a heart from a seropositive donor, and 3 of these 4 had seroconversion and developed life-threatening toxoplasmosis; the remaining 27 did not have seroconversion or develop clinical toxoplasmosis. Of 19 patients who had antibodies to Toxoplasma before transplantation, 10 developed significant increases in test titers of the dye test or double-sandwich IgM enzyme-linked immunosorbent assay but did not develop a clinical illness that could be attributed to toxoplasma infection. Significant serologic changes occurred more often in patients who received azathioprine, corticosteroids, and antithymocyte globulin than in those who received cyclosporine, corticosteroids, and antithymocyte globulin (p less than 0.05). These data show the wide clinical spectrum and differences in kinetics of antibody response of patients who develop toxoplasma infection after transplantation, and suggest that clinical disease occurs in those who have seroconversion but is rare in patients with preexisting antibody who have serologic evidence of recrudescence.

Dye Dilution Technique↗

[Non-Hodgkin's lymphoma with Toxoplasma encephalitis].

A 62-year-old man was admitted to our hospital due to fever and systemic lymph-node swelling on June 9, 1998. He was given a diagnosis of non-Hodgkin's lymphoma (diffuse mixed T cell lymphoma) with involvement of mediastinum and para-aortic lymph nodes, pleura, peritoneum, and bone marrow. After diagnosis, combined chemotherapy (CHOP regimen) was started. On day 11, the patient's consciusness level suddenly deteriorated. A brain computed tomographic scan showed no abnormal findings. A cytospin smear of cerebrospinal fluid disclosed tachyzoides (Toxoplasmic bodies), thus yielding a diagnosis of Toxoplasma encephalitis. Oral sulfadoxine pyrimethamine rapidly alleviated the patient's consciousness disturbance. One month later, a cytospin smear and RT-PCR analysis of cerebrospinal fluid detected no tachyzoides. Complete remission of lymphoma was achieved after 2 courses of CHOP therapy. Toxoplasma encephalitis should be considered a potential cause of consciousness disturbance in immunocompromised hosts, such as patients with malignant lymphoma. Cytospin smears of cerebrospinal fluid are a useful tool for the early diagnosis of Toxoplasma encephalitis.

Animals↗

[Characteristics of Toxoplasma-gondii-tachyzoites from different culture systems]

Toxoplasma gondii is an intracellular protozoan parasite of worldwide distribution. Parasites that habour a complete antigenic profile, that is necessary for the serological diagnosis of human Toxoplasma infections, are provided by in vivo culture methods only. It seems that the host immune pressure is responsible for the expression of a total antigen pattern. Thus, in most laboratories the asexual proliferative stage of the parasite, the tachyzoite, is maintained by successive intraperitoneal passages in highly susceptible animals such as mice. We would like to develop an in vitro method to provide sufficient amounts of high quality parasite antigen suitable for diagnosis of Toxoplasmosis. Using the RAPD-PCR (random amplified polymorphic DNA-PCR) technique, we were able to show that during different culture conditions (in vivo and in vitro culture) the parasites undergo no clonal selection. That means the entire parasite population changes the protein expression pattern due to the in vitro culture conditions. Based on the result described previously the work could be continued as follows. One strategy could be to simulate the host immune pressure during the in vitro cultivation of the tachyzoites. A more convinced approach may be the production of recombinant parasite antigens useful for diagnosis of a Toxoplasma infection in human adults and newborns.

Journal Article↗

Seropositivity of Toxoplasma gondii in domestic animals.

Serum samples from 107 goats, 40 sheep, 50 cows were tested for Toxoplasma gondii antibody by indirect haemagglutination test (IHA) in dilutions of 1:10, 1:54, 1:162 and 1:486. Toxoplasma gondii-antibodies were found in 21 (19.6%), 10 (25%), 26 (52%), goat, sheep and cow sera respectively. No serum sample showed a titre higher than 1:162. All animals were kept in good hygienic condition. These results indicate that Toxoplasma gondii antibodies are widespread in animal populations which supports that toxoplasmosis is a widely spread zoonotic infection in this country.

Animal Diseases↗

Treatment of Toxoplasma brain abscess with clindamycin and sulfadiazine in an AIDS patient with concurrent atypical Pneumocystis carinii pneumonia.

Toxoplasmosis is the most common opportunistic infection of the central nervous system in patients with AIDS. The standard treatment for toxoplasmic encephalitis is pyrimethamine and sulfadiazine. There have been few reports of concurrent Toxoplasma brain abscess and cavitary Pneumocystis carinii pneumonia (PCP) in Taiwan. We report the case of a 26-year-old homosexual man with coexisting infection with Toxoplasma gondii and P. carinii who was successfully treated for brain abscess with clindamycin and sulfadiazine. The cavitary lung lesions, initially diagnosed as pulmonary tuberculosis, were proved to be PCP by lung biopsy. HIV infection and syphilis had been diagnosed 1 year before admission. He presented with general weakness, ataxia, nausea, blurred vision and fever for 2 weeks. Magnetic resonance imaging of the brain revealed multiple ring-enhanced lesions over the cerebrum and cerebellum. Chest roentgenography showed a 3-cm lesion with cavitation over the right upper lung field. Diagnostic computerized tomography-guided lung biopsy revealed P. carinii cysts. Clindamycin, sulfadiazine and trimethoprim (TMP)-sulfamethoxazole (20 mg/kg/day TMP) were given with good response. His CD4 count rose from 40 to 280/microL 4 months later. All antibiotics were discontinued after 4.5 months due to the development of a skin rash. He was well at follow-up 1 year later. This case suggests that the combination of clindamycin and sulfadiazine is an effective treatment for Toxoplasma brain abscess and highlights the importance of diagnostic lung biopsy for cavitary lung lesions, particularly in a region endemic for tuberculosis.

AIDS-Related Opportunistic Infections↗

[Outcome of gestation of 32 pregnant women with toxoplasma and cytomegalovirus infection].

In an attempt to investigate the harmful effects of the infection of Toxoplasma and associated with cytomegalovirus on the fetus infection acquired transplacentally during their mothers' pregnancy sera from 1000 pregnant women were tested for antibodies to both pathogens and the circulating antigen of Toxoplasma by using ELISA. The test was positive (titre > or = 1:60400) in 32 of 1000 cases. Judging from the sero-positive results together with the case history, clinical manifestations and B-scan results, the 32 cases were advised to end their pregnancy. Necropsy and pathological examinations of the foetuses revealed stillborn foetus, hydrocephalus, acephalus, pleural effusion, ascites and other congenital malformations. Toxoplasma gondii were found in the tissues of 21 fetuses.

Adult↗

Toxoplasma gondii antibody in Thai cats and their owners.

Humans are thought to acquire Toxoplasma infection by three major routes: ingesting food and water contaminated with oocysts from cat excreta, consumption of under-cooked infected meat, and transplacental transfer. Congenital clinical toxoplasmosis in the newborn indicating definite transplacental transmission had been reported in Thailand, whilst studies concerning infection due to the other two routes were inconclusive. Since the way domestic cats live and eat and also the eating behavior of Thai people differ from those in the West, we conducted a sero-epidemiological study of T. gondii in cats and their owners in Bangkok metropolitan area. Among 327 humans, the prevalence of Toxoplasma antibody was 6.4% and in 315 cats it was 7.3%. These relatively low prevalence rates may result from the predominantly well-cooked fish and rice diet of stray cats, which congregate in temples where they are fed. Toxoplasma antibody seropositive was associated with living in close proximity to seropositivity cats [OR (95% CI) = 5.43 (1.28-23.04); p=0.01]. Risks were increased in and around temples, particularly if courtyards were of earth or grass, suggesting ground temperature was an important determinant of oocyst survival.

Adolescent↗

Prevalence of antibodies to Toxoplasma gondii among farmers and cattle in Gombak District, Selangor, Malaysia - a preliminary report.

A survey was carried out to determine the prevalence of Toxoplasma gondii antibodies among cattle farmers and cattle in the Gombak District, Selangor. A total of 79 human and 73 cattle serum samples were tested for Toxoplasma gondii antibodies by the immunofluorescent technique (IFAT). Results of the survey showed that anti-Toxoplasma gondii antibodies were found in 27.8% of the farmers, while in cattle the positive rate was only 3.8%. The prevalence rate obtained in this study did not differ much from the prevalence reported in previous studies. This suggests that the same degree of risk to this infection exists in the community. In view of the relatively low antibody prevalence in cattle, the risk of acquiring this infection from consuming undercooked beef is realtively low. Further survey on larger sample size is needed to validate the observation.

Journal Article↗

[Investigation of anti-Toxoplasma antibodies in patients with hematological malignancy.].

Anti-Toxoplasma IgG and IgM antibodies were investigated using IFA and ELISA techniques in 40 patients with the diagnosis of leukemia or lymphoma and in a control group of 40 healthy persons. IgG seropositivity in the patient and control groups was found to be 67.5% and 60.0%, respectively, using IFA, and 60.0% and 62.5%, respectively, using ELISA (p > 0,05 for all). The agreement of the methods was high (kappa=%89). Anti-Toxoplasma IgM antibody was not found in either of the groups. Twenty-seven individuals with IgG seropositivity in the patient group were under the risk of reactivation and 13 IgG seronegative individuals were under risk of acquiring severe primary toxoplasmosis. Anti-Toxoplasma antibodies should be screened in patients when leukemia or lymphoma is diagnosed, and direct detection methods should be applied especially in the patients who have signs indicating central nervous system involvement.

English Abstract↗

Prevalence of toxoplasma antibodies among women with BOH and general population in Delhi.

One thousand and thirty-six serum samples obtained from women with bad obstetric history (BOH) were subjected to detection of toxoplasma antibody by indirect immunofluorescent antibody test (IFAT) using whole promastigotes of Rh strain of Toxoplasma gondii as antigen. Thirtyone (2.99 per cent) samples were found to be positive (titre greater than or equal to 1:64). Of these 31 patients' sera 27 (87.09 per cent) showed rising titre of antibody when second samples were drawn after 4 weeks. Two hundred serum samples from general population were also assayed and only 2 (1 per cent) were found to be having toxoplasma antibodies in titre of 1:64. The observations suggest low prevalence of toxoplasmosis in and around Delhi which is in consonance with the food habits of local people and their infrequent contact/association with cats.

Antibodies, Protozoan↗

Pneumocystis carinii, Toxoplasma gondii, Cytomegalovirus and the compromised host.

Pneumocystis carinii and Toxoplasma gondii are the two major parasitic protozoan pathogens in the immunocompromised host. Both organisms cause latent infection in humans and many animals. Cats are the definitive hosts for toxoplasmosis; the animal vector for pneumocystis (if any) has not been defined. Toxoplasma is an obligate intracellular parasite, whereas the available evidence suggests that Pneumocystis carinii exists primarily extracellularly. In compromised hosts, pneumocystis infection usually involves only lungs, whereas toxoplasma causes a generalized infection with encephalitis being the principal clinical manifestation. Both types of infection are treated with combinations of folate antagonists (trimethoprim or pyrimethamine with sulfonamide). Both parasites are associated with cytomegalovirus infection in immunosuppressed hosts, an association which may be due to symbiosis between parasites, or to an additive immunosuppressive effect of dual infection on the hosts.

Adolescent↗

Toxoplasma gondii pneumonia in patients with the acquired immunodeficiency syndrome.

PURPOSE: To perform a retrospective and descriptive study of Toxoplasma gondii pneumonia in patients infected with the human immunodeficiency virus (HIV). Clinical presentation, diagnostic procedures, results of therapy, and hypotheses on pathophysiology are discussed. PATIENTS AND METHODS: The study consisted of 13 HIV-infected patients who had developed T. gondii pneumonia. Eight had acquired immunodeficiency syndrome (AIDS) prior to T. gondii pneumonia and three of them had non-Hodgkin's lymphoma. Mean CD4 cell count was 32 x 10(6)/L. Serum anti-toxoplasma antibody titers were measured by an indirect hemagglutination assay and/or by an indirect immunofluorescence assay. RESULTS: All patients had fever and bilateral pulmonary infiltrates; two of them presented with septic shock. Mean arterial oxygen tension was 47 +/- 12 mm Hg. The diagnosis was established by bronchoalveolar lavage in 10 of 11 cases, open lung biopsy in one case, and postmortem biopsy in two cases. Serologic evidence of past infection was observed in 11 of 12 cases, while one patient presented with acute disseminated disease and absence of serum anti-toxoplasma antibody response. Extrapulmonary involvement was present in seven patients: liver (four), brain (three), bone marrow (two), heart (two), stomach (one). Ten patients recovered from T. gondii pneumonia. CONCLUSION: T. gondii pneumonia must be considered in AIDS patients with severe diffuse bilateral pneumonia, especially when associated with a very low CD4 cell count or non-Hodgkin's lymphoma. In most of these cases, disseminated disease was associated with reactivation of prior latent infection.

Acquired Immunodeficiency Syndrome↗

Immune responses associated with early survival after peroral infection with Toxoplasma gondii.

After peroral infection with cysts of Toxoplasma gondii, C57BL/6 mice died and A/J mice survived. To better understand the reasons for this difference in survival, host defenses during acute infection were studied: initial portal of entry of T. gondii contributed to susceptibility as more C57BL/6 mice survived after i.p. than peroral infection (p less than 0.001). Susceptible (C57BL/6) mice had more necrosis and inflammation in their brains, livers, and mesenteric lymph nodes than resistant (A/J) mice. Susceptible mice had less IgM antibody to T. gondii (p less than 0.0005) than resistant mice 7 days after infection, but amounts of IgG antibody to T. gondii were similar. Infection reduced percentages of spleen cells with the Lyt-2+ phenotype in susceptible (p less than 0.02) but not resistant mice; infection decreased percentages of spleen cells with the L3T4+ phenotype similarly in both strains of mice. Spleen cells from infected susceptible mice had greater depression in their blastogenic response to Con A (p less than 0.05) and produced significantly more IFN-gamma in culture with (p = 0.009) or without (p less than 0.05) Toxoplasma Ag than spleen cells from infected resistant mice. Infection increased serum levels of IFN-gamma substantially in susceptible but not resistant mice. Lymphocyte IL-2 production was similar in both groups of mice. Peritoneal macrophages from both strains of mice became activated to inhibit or kill T. gondii by 7 days after infection, but Kupffer cells became activated only in susceptible mice. These results indicate that increased resistance to peroral Toxoplasma infection is likely to be mediated by a number of immune responses acting together. They suggest that increased susceptibility may result from inadequately regulated inflammatory responses that increase tissue destruction.

Animals↗

Serological responses in Sarcocystis cruzi infected calves challenged with Toxoplasma gondii.

Three four-week-old calves were used in a study on serological responses in combined Sarcocystis cruzi and Toxoplasma gondii infections. One calf (C1) was inoculated orally with 100,000 S cruzi sporocysts, another (C2) with 40,000 sporocysts, while the third (C3) acted as uninfected control. One hundred and five days later, all three calves were inoculated orally with 100,000 T gondii oocysts. The antibody responses to sarcocystis and toxoplasma during 210 days were recorded, using different serological assays. During the S cruzi monoinfection phase, positive antibody reactions were recorded in C1 and C2, using an ELISA with soluble (cytoplasmic) T gondii tachyzoite antigen, while antibody reactions remained negative in the toxoplasma indirect fluorescent antibody test and in an ELISA employing T gondii tachyzoite cell membrane antigen. However, the Sabin Feldman dye test also showed transient low positive titres for C1 and C2 at around day 39 after S cruzi inoculation. When using an ELISA employing soluble S fusiformis cystozoite antigen, increased sarcocystis antibody counts were recorded for C1 and C2 starting two weeks after T gondii inoculation. Otherwise the three calves reacted as expected regarding the general antibody responses to the S cruzi and T gondii infections.

Animals↗

Effects of nontoxic lipid A and endotoxin on resistance of mice to Toxoplasma gondii.

Mice were administered nontoxic monophosphoryl lipid A (MPL) or refined standard bacterial endotoxin (RSE) prior to, simultaneously with, or after infection with Toxoplasma gondii. MPL and RSE given before or with the toxoplasma infection induced significant resistance. Administration of toxic RSE, but not nontoxic MPL, after the establishment of toxoplasma infection significantly shortened the survival time of mice.

Animals↗

Epizootiologic investigations on a sheep farm with Toxoplasma gondii-induced abortions.

During the lambing season of 1983/1984, 8 of 44 purebred Hampshire ewes on a farm in Knoxville, Md had reproductive problems. In at least 4 of these ewes, the problem was attributed to toxoplasmosis. Necrosis and Toxoplasma gondii tachyzoites were found in placental specimens from 3 ewes. Agglutinating antibody to T gondii, at a titer of 1:80, was found in pleural fluids of both fetuses aborted from 1 ewe; this ewe had an antibody titer of 1:6,400 at the time of abortion. In another ewe, the diagnosis was confirmed by the isolation of T gondii from the placenta and 1 of her lambs. Of numerous free-roaming adult cats on the farm, 16 were trapped, euthanatized, and examined for T gondii. Agglutination antibody to T gondii, at titers of 1:4 to 1:64, was found in serum samples from all the cats. Toxoplasma gondii was isolated from the brain and skeletal muscles of 9 of the cats, and from the feces of 1 cat. Blood samples obtained from all 78 sheep on the farm 6 months after the episode of abortion were examined for antibody to T gondii. Agglutinating antibody titers to T gondii were less than 1:16 in 46 sheep, 1:16 in 16, 1:64 in 12, 1:256 in 2, 1:024 in 1, and 1:4,096 in 1. Analyses of serologic data in sheep of various age groups suggested that the Toxoplasma infection was acquired sporadically, probably from feed contaminated with oocysts.

Abortion, Veterinary↗