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Toxoplasmosis in black-faced kangaroos (Macropus fuliginosus melanops).

An epizootic of toxoplasmosis among captive black-faced kangaroos (Macropus fuliginosus melanops) is reported. Eight of 25 adult kangaroos had antibodies to Toxoplasma gondii. Serologic data indicated recent exposure to T. gondii in six kangaroos. Two kangaroos had high T. gondii antibody titers (greater than or equal to 16,384) in the modified agglutination test and their infants died when less than 7 months old. Toxoplasma gondii tachyzoites were found in several organs of one infant kangaroo (joey) that died at about 82 days of age and numerous cysts were seen in skeletal muscles of the other joey that died at about 7 months of age. Adult kangaroos had subclinical infections. The modified agglutination test and the dye test were more sensitive than the indirect hemagglutination and latex agglutination tests for the detection of T. gondii antibodies in kangaroo sera.

Agglutination Tests↗

Congenital toxoplasmosis in Abyssinian cats.

Two of three litter-mate kittens born to an Abyssinian cat died of acute toxoplasmosis. Toxoplasma gondii was found in histologic sections of both kittens and this was confirmed by immunoperoxidase staining.

Animals↗

The epidemiology of toxoplasmosis on Iowa swine farms with an emphasis on the roles of free-living mammals.

Multiparous sows from 19 central Iowa swine farms were tested for antibodies against Toxoplasma gondii by the modified direct agglutination test. Antibody titers of 1:32 or greater were considered positive. Rodents, domestic cats, opossums (Didelphis virginiana), raccoons (Procyon lotor) and striped skunks (Mephitis mephitis) were live-trapped on each farm and similarly tested for antibodies. The overall prevalence of T. gondii antibodies in the species tested was 39/273 (14.3%) swine, 31/74 (41.9%) cats, 2/588 (0.3%) house mice (Mus musculus), 0/21 mice of the genus Peromyscus, 0/9 Norway rats (Rattus norvegicus), 1/34 (2.9%) opossums, 4/14 (28.6%) raccoons and 2/7 (28.6%) striped skunks. The overall prevalence was significantly greater in adult cats versus juvenile cats, adult male cats versus adult female cats, and adult raccoons versus juvenile raccoons. The prevalence of T. gondii antibodies in sows was compared with the prevalence in each non-swine species on a farm basis in order to identify existing associations. The prevalence in sows (and each of the non-swine species) was also analyzed on a farm basis for association with farm characteristics or swine management practices, including the degree of confinement of swine, population size and average parity of breeding female swine, estimated cat population size, and estimated mouse and rat abundance. Average titers of seropositive animals were compared on a species basis. The prevalence in sows which were totally and continuously confined was lower than that in sows which were not totally and continuously confined. The prevalence in sows from farms with an average parity of less than 2.0 was significantly lower than that in sows from farms with an average parity of 2.0 or greater. These results suggested that the prevalence of T. gondii antibodies in swine increased with age and that prevalence in swine could be reduced through total confinement. No associations could be established between prevalence in sows and prevalence in non-swine species or other farm characteristics/swine management practices. However, the high prevalence of T. gondii antibodies in cats suggested that fecal contamination of the environment by cats may be the most significant source of toxoplasmosis for swine. The extremely low prevalence of T. gondii antibodies in house mice suggested that this species was not an important source of T. gondii for swine in Iowa.

Animals↗

Acute toxoplasmosis in a gray fox (Urocyon cinereoargenteus).

Toxoplasmosis was diagnosed in a gray fox (Urocyon cinereoargenteus) found moribund in Lake Loundes Park, Mississippi. There was almost total necrosis of mesenteric lymph nodes, focal hemorrhage and necrosis in the brain. Lesions in all of these organs were associated with numerous Toxoplasma gondii tachyzoites. Tissue cysts were seen in the brain. Organisms reacted with anti-T. gondii serum in an avidin-biotin immunohistochemical test. There was no evidence of concurrent distemper or rabies virus infection. Hammondia heydorni-like schizonts and gamonts were seen in sections of intestinal epithelium.

Animals↗

MRI evaluation of AIDS-related encephalopathy: toxoplasmosis vs. lymphoma.

The spectrum of cranial MRI findings was evaluated in 113 patients with the acquired immunodeficiency syndrome, assessing lesion number, size, location, and configuration in association with the autopsy and/or biopsy results. Correlation of cranial MRI and CT was performed in 32 patients. MRI was shown to be superior in sensitivity of lesion detection demonstrating more lesions than CT in 14 studies (44%) and equivalent information in 18 studies (56%). In no case did CT demonstrate lesions not detected on MRI. We conclude that MRI should be the study of choice in evaluating AIDS-related encephalopathy. Multiple lesions that involve both deep gray matter and white matter suggest the possibility of CNS lymphoma. The "target" appearance on MRI is not helpful in distinguishing toxoplasmosis from lymphoma.

AIDS Dementia Complex↗

Effects of immobilization stress on the pathogenesis of acute murine toxoplasmosis.

Stress modulates a variety of immune responses. We investigated the effects of immobilization stress on the pathogenesis of acute murine toxoplasmosis, an infection in which cell-mediated immunity is of major importance in host defense. Repetitive overnight immobilization beginning 3 days prior to infection enhanced (p less than 0.05) the mortality of mice infected with a virulent strain (C56) of Toxoplasma gondii (77% vs 15% mortality in restrained and control mice, respectively). Daily immobilization for 14 days prior to infection abrogated (p less than 0.05) the lethal effect of immobilization, suggesting an adaptive mechanism. To explore the effect of immobilization with a less virulent strain, the Me49 strain of T. gondii was studied. Acute infection with T. gondii Me49 resulted in anorexia and weight loss, while spleen size and respiratory burst activity of peritoneal exudate cells were enhanced (p less than 0.01). Immobilization (twice daily for 2 h) did not significantly alter survival or other clinical features of acute T. gondii infection. In addition, immobilization suppressed (p less than 0.05) phorbol myristate acetate-stimulated release of superoxide anion by peritoneal exudate cells in healthy naive mice, but not in infected mice. These findings indicate that immobilization stress can alter the pathogenesis of acute T. gondii infection in healthy mice, but the effect of this stress paradigm will be influenced, in part, by the timing of the immobilization and the virulence of the strain of T. gondii.

Animals↗

Development of membrane-based tests for the detection of urinary antigens and antibodies in human toxoplasmosis: preliminary studies in Ghanaian patients.

Two membrane-based ELISA systems were used in detecting Toxoplasma antigens and anti-Toxoplasma antibodies in urine samples collected from 54 ophthalmology (22 suggestive active and 32 suggestive past infection) patients and 26 pregnant women attending obstetrics/gynaecology clinic (OGP), suspected of toxoplasmosis by eye examination, past medical records and questionnaire, respectively, in Ghana from mid-February to April 2002. The antigen detecting ELISA was able to demonstrate antigen in 100% (22/22) ophthalmology (active infection) and 62.5% (20/32) ophthalmology (past infection) patients, and 42% (11/26) of OGP which included 3 that were sero-negative prior to and during this study, giving an overall prevalence of 66.3% (53/80). The urinary antigen positive samples also included 6 that were negative for both the Dye Test (DT) and latex agglutination test (LAT). Antigen was not detected in the urine of 22 normal (sero-negative for antibodies to Toxoplasma) individuals. The membrane-based urinary antibody detecting sandwich ELISA also detected anti-Toxoplasma antibodies in 100% (22/22) of ophthalmology (active infection) and 81.3% (26/32) of ophthalmology (past infection) patients, a total of 89% (48/54); and 80.8% (21/26) of OGP with an overall prevalence of 86.3% (69/80), including 7 ophthalmology patients' samples that were sero-negative for both DT and LAT. Antibody sero-positivity of the samples was determined by DT as 87% (47/54) in ophthalmology patients and 73.1% (19/26) in pregnant women, LAT as 85.2% (46/54) and 65.4% (17/26), and an overall prevalence as 82.5% (66/80) and 78.8% (63/80), respectively. The membrane-based ELISA systems appear promising but need to be investigated further for its efficacy as reliable diagnostic tests.

Adolescent↗

Third-generation optical coherence tomography findings in punctate retinal toxoplasmosis.

PURPOSE: To investigate optical coherence tomography (OCT) findings in patients with punctate retinal toxoplasmosis (PRT). DESIGN: Observational case series. METHODS SETTING: Tertiary ophthalmic referral center. STUDY POPULATION: Four patients with PRT consecutively evaluated between July 2004 and June 2005. OBSERVATION PROCEDURES: Clinical examination and OCT. MAIN OUTCOME MEASURES: Morphologic features at baseline and changes within a 24-week follow-up interval. RESULTS: Retinal layers were abnormally hyperreflective at the active lesion site and associated with some degree of retinal pigment epithelium-choriocapillaris/choroidal optical shadowing in all patients. The posterior hyaloid was thickened and focally detached (over the lesion). Additional findings include tractional maculopathy (n = 2) and diffuse macular edema (n = 1). During follow-up, focal choriocapillaris/choroidal relative hyperreflectivity was observed at the former lesion site, and posterior vitreous detachment progressed in all patients. CONCLUSIONS: Our findings suggest that OCT may enable identification of subtle morphologic features previously underappreciated in patients with PRT, which may provide new insights about the disease pathophysiologic mechanisms.

Antiprotozoal Agents↗

Nocardia abscess during treatment of brain toxoplasmosis in a patient with aids, utility of proton MR spectroscopy and diffusion-weighted imaging in diagnosis.

We report the case of a 30-year-old man with known HIV-positive status who developed, 4 months prior to admission, recurrent left partial motor seizures followed by left hemiparesis. At another hospital, contrasted CT scan of the head revealed right frontal hypodense lesion with mass effect and focal contrast enhancement. A small left occipital lesion was also present. HIV-associated brain toxoplasmosis was considered and phenytoin, pyrimethamine, clindamycin and antiretrovirals were administered. Hemiparesis improved but, 3 weeks prior to admission, he developed progressive headache and bilateral visual defects. Upon admission to our center, he was found with left homonymous hemianopsia, right hemiparesis and a large hypodense left occipital lesion on a head CT scan. Proton MR spectroscopy showed lactate at 1.3ppm, amino acids at 0.9ppm, and diffusion-weighted imaging (DWI) revealed hyperintensity at the lesion, suggesting a pyogenic abscess. Aspiration yielded purulent material and Nocardia asteroides grew in culture. The patient was treated with trimethoprim-sulfametoxazole and recovered with a mild visual field residual defect.

Acquired Immunodeficiency Syndrome↗

Biases in observational studies of the effect of prenatal treatment for congenital toxoplasmosis.

The paper reviews methodological difficulties that arise when using observational studies to evaluate the effect of prenatal screening and treatment. The principle of each difficulty is described and then illustrated by a clinical example of toxoplasmosis in pregnancy and its consequences. Methods to deal with these difficulties are described. Given the limitations of existing observational studies and lack of randomised controlled trials, a systematic review of cohort studies offers the best approach for exploring potential biases.

Adult↗

The International Congress on Toxoplasmosis.

Toxoplasma gondii is an important pathogen in both veterinary and human medicine. Infection during pregnancy can result in fetal transmission and a congenital infection syndrome. In immune-compromised hosts reactivation of latent infection can result in encephalitis. It has been estimated that as many as one-third of the human population harbours this zoonosis. The Seventh International Congress on Toxoplasmosis, organised by Louis M. Weiss and Kami Kim (Albert Einstein College of Medicine, Bronx, NY) was held on 23-27 May 2003 in Tarrytown, New York. At this meeting 133 investigators from 14 countries presented 102 papers on research involving this model Apicomplexan parasite. The presented research covered the epidemiology, immunology, cellular biology and molecular biology of this pathogen.

Animals↗

The involvement of autoimmunity against retinal antigens in determining disease severity in toxoplasmosis.

PURPOSE: Ocular lesions are frequent in various individuals infected with Toxoplasma gondii. Disease intensity in ocular toxoplasmosis varies greatly between patients. Autoimmunity has been suggested as a possible component to retinal destruction. METHODS: Immunologic parameters in the response to retina antigens were evaluated in infected persons with and without ocular lesions and in non-infected controls. Subjects were divided into groups on the basis of titers of serum antibodies to T. gondii, presence and severity of ocular lesions, and clinical history. RESULTS: Peripheral blood mononuclear cells from patients with mild disease responded to one or more retinal antigens with a significantly higher frequency than patients without disease or with severe disease. Interestingly, the cytokines produced by the proliferating mononuclear cells did not follow any specific patterns, except for the fact that IL-4 and IL-5 were seldom detected. CONCLUSIONS: Our results suggest that although the presence of an immune response towards autoantigens is not protective against the development of ocular lesions by the T. gondii, it may protect against the development of severe disease.

Antigens↗

Simultaneous determination of pyrimethamine, sulfadiazine and N-acetyl-sulfadiazine in plasma for monitoring infants in treatment of congenital toxoplasmosis.

A method for the simultaneous determination of pyrimethamine, sulfadiazine and its metabolite N-acetyl-sulfadiazine in small plasma samples from neonates in treatment for congenital toxoplasmosis has been developed. In this method only 25 microl of plasma is used and a simple sample preparation based on protein precipitation and centrifugation provides highly reliable data as the recovery is about 100% and the precision is good. The analysis is performed using high performance liquid chromatography with UV and mass spectrometric (MS) detection. Pyrimethamine was found to give a linear response using MS detection in the range 0.02-5 microg/ml. Sulfadiazine and its metabolite N-acetyl-sulfadiazine were preferably analysed by UV at 269 nm in the concentration ranges 0.2-200 microg/ml for sulfadiazine and 0.2-50 microg/ml for N-acetyl-sulfadiazine.

Chromatography, High Pressure Liquid↗

1,25-Dihydroxyvitamin D3 induces splenocyte apoptosis and enhances BALB/c mice sensitivity to toxoplasmosis.

The hormonal form of Vitamin D, 1,25-dihydroxyvitamin D3, is well known for its immunosuppressive, anti-proliferative and pro-apoptotic activities. In the present work, we studied the effect of 1,25-dihydroxyvitamin D3 on Toxoplasma gondii-infected mice. We observed that 1,25-dihydroxyvitamin D3 reduces the survival rate of infected mice by up to 37% at day 10 post-infection compared to untreated infected mice (P < 0.0001). IFN-gamma and IL-12p40 levels were significantly reduced by 1,25-dihydroxyvitamin D3 in infected mice sera indicating an inhibition of Th-1-type cytokines. CD4+ T lymphocyte and splenocyte counts were also reduced following 1,25-dihydroxyvitamin D3 treatment and a marked induction of apoptosis, accompanied with down-regulation of the anti-apoptotic proteins Bcl-2 and Bcl-X(L), was observed. The above results indicate that 1,25-dihydroxyvitamin D3 induces splenocyte apoptosis and enhances host susceptibility to toxoplasmosis.

Animals↗

Toxoplasmosis after a simultaneous pancreas and kidney transplantation.

We report the case of a simultaneous kidney and pancreas transplant recipient who presented with vague neurologic symptoms 21 months following the surgery. Computed tomography, magnetic resonance imaging, and fundoscopy findings were normal. Serology titers for antitoxoplasmic antibodies were increased. This was an atypical presentation of toxoplasmosis in a simultaneous kidney and pancreas transplant patient.

Adult↗

Survey of ovine and caprine toxoplasmosis by IFAT and PCR assays in Sardinia, Italy.

During the period 1999-2002, we have analyzed 9639 serum samples and 815 aborted samples (670 fetuses and 145 placenta) from 964 ovine and caprine farms distributed over all Sardinia island. After abortion notification, sera collected at random from adult animals were examined to detect simultaneously IgG and IgM antibodies specific to Toxoplasma gondii by indirect immunofluorescence assay, whereas fetuses and placenta were analyzed by a single tube nested PCR assay. Specific IgG antibodies were detected in 2048 (28.4%) sheep and 302 (12.3%) goats, specific IgM antibodies were found in 652 (9%) sheep and 139 (5.6%) goats. From a total of 2471 ovine and 362 caprine fetal samples including muscle, liver, abomasum, spleen, brain and placenta, 271 (11.1%) ovine and 23 (6.4%) caprine samples were T. gondii PCR-positive. Although T. gondii DNA was amplified from different types of tissues, placenta was the tissue with the highest detection rate. On the one hand, these results indicate that the seroprevalence of T. gondii infection in sheep and goats is relatively high, on the other PCR results demonstrate that T. gondii has a significant role in ovine and caprine abortion. Adequate management might be useful and essential to control the toxoplasmosis in the sheep and goats herds of Sardinia.

Aborted Fetus↗

Fatal toxoplasmosis and concurrent Calodium hepaticum infection in Korean squirrels (Tanias sibericus).

Four Korean squirrels (Tanias siberius) imported in Spain from People's Republic of China died 2 days after their arrival at a pet shop. They had neurological signs associated with generalized toxoplasmosis involving brain, lungs, liver, and the heart. Toxoplasma gondii-like tachyzoites and tissue cysts were found in organs of all four squirrels. The protozoa stained positively with T. gondii polyclonal antibodies and were ultrastructurally similar to T. gondii. Calodium (Capillaria) hepaticum infection was found in the liver of one squirrel.

Animals↗

Comparative serological diagnosis of toxoplasmosis in horses using locally isolated Toxoplasma gondii.

A total of 420 serum samples collected from horses of different ages, sexes and breeds, located at some horse farms in Egypt, were used for serological studies. A crude antigen of the locally isolated Toxoplasma gondii tachyzoites from horse tissues (LA) was used for the detection of T. gondii antibodies in horses. It showed good diagnostic efficiency (38.1%) by Enzyme Linked Immunosorbent Assay (ELISA). To increase this efficiency, an affinity purification process was performed. Two fractions were obtained from LA by CNBr-Sepharose 4B affinity column chromatography named; unbound (LAunb) and bound (LAb). LAb showed the highest diagnostic potency (51.7%), while LAunb showed the lowest value (31.7%) using ELISA. The electrophoretic profile of LA (12 bands), LAb (6 bands) and LAunb (6 bands) showed molecular weights ranged from 25.1 to 184.3kDa. The immunoreactive bands of each of the three antigens were identified with infected horse sera by immunoblot assay. Four immunogenic bands of 155.8, 115.1, 83.2 and 66.2kDa were identified in LAb and probably were responsible for the highest diagnostic potency. Examination of horse sera by Indirect Fluorescence Antibody Test (IFAT) at a dilution of 1: 64 and Modified Agglutination Test (MAT) at a dilution of 1: 25 revealed that 170 (40.5%) and 202 (48.1%) had antibodies against T. gondii, respectively. The current research introduces crude and purified fractions (bound and unbound) obtained from the locally isolated tachyzoites (equine origin), which are utilized globally for the first time in detection of T. gondii antibodies in horses. Furthermore, this study recommended utilization of the bound fraction in diagnosis of toxoplasmosis using indirect ELISA which proved better diagnostic potency compared with IFAT and MAT.

Agglutination Tests↗