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oocyst-induced murine toxoplasmosis: life cycle, pathogenicity, and stage conversion in mice fed toxoplasma gondii oocysts.the development of sporozoites to tachyzoites and bradyzoites was studied in mice after feeding 1-7.5 x 10(7) toxoplasma gondii oocysts. within 2 hr after inoculation (hai), sporozoites had excysted and penetrated the small intestinal epithelium. at 2 hai, most sporozoites were in surface epithelial cells and in the lamina propria of the ileum, and by 8 hai, t. gondii was also seen in mesenteric lymph nodes. at 12 hai, sporozoites had divided into 2 tachyzoites in the lamina propria of the small ...19979379292
low seroprevalence of toxoplasma gondii in feral pigs from a remote island lacking cats.serum samples from 1,264 feral pigs from ossabaw island, georgia were initially screened for antibodies to toxoplasma gondii by the modified agglutination test (mat) using whole-formalinized tachyzoites and mercaptoethanol. seropositive samples were also tested by the sabin-feldman dye test, the latex agglutination test (lat), and the indirect hemagglutination test (ihat). ossabaw island is a remote, barrier island located southeast of savannah, georgia. antibodies to t. gondii were found in 11 ...19979379287
elevated interleukin 6 activity in aqueous humor of cats with uveitis.the purpose of this study was to assess the role of interleukin 6 (il-6) in feline uveitis by measuring il-6 activity in the serum and aqueous humor of cats. serum and aqueous humor was collected from clinically normal, random source cats (n = 10); clinically normal, specific-pathogen free cats experimentally inoculated with toxoplasma gondii strain me49 and sampled sequentially for 20 months (n = 4); and client-owned cats with uveitis (n = 27). interleukin 6 activity was measured in each sample ...19979343336
distribution of tissue cysts in organs of rats fed toxoplasma gondii oocysts.toxoplasma gondii-infected rats are considered important in the epidemiology of toxoplasmosis because they can serve as a source of infection for pigs and possibly for cats. to study the distribution of tissue cysts, 10 sprague-dawley female adult rats were fed 1 oocyst (3 rats, group a) or 10(5) oocysts (3 rats, group b) of the veg strain or 10(4) oocysts of the gt-1 strain (4 rats, group c) of t. gondii. all rats in a group were killed at 1 time: 76 (group a), 240 (group b), and 443 (group c) ...19979267423
a serological survey of feline immunodeficiency virus and toxoplasma gondii in stray cats. 19979232779
tissue cyst tropism in toxoplasma gondii: a comparison of tissue cyst formation in organs of cats, and rodents fed oocysts.the persistence of toxoplasma gondii tissue cysts in organs of cats (definitive host) and rodents (intermediate hosts) was studied. nine cats, 12 rats, and 12 mice were fed t. gondii oocysts and their organs were digested in pepsin and then bioassayed for bradyzoites in mice. of 9 cats killed 37 or 51 days after feeding 10(2) (2 cats), 10(3) (3 cats) or 10(4) (4 cats) oocysts of the veg strain, tissue cysts were found in each cat; in the tongue of 9, in the heart of 5, in the brain of 4, and in ...19979226953
isolation of coccidian enteroepithelial stages of toxoplasma gondii from the intestinal mucosa of cats by percoll density-gradient centrifugation.a method for isolation of enteroepithelial stages of toxoplasma gondii from the intestinal mucosa of experimentally infected cats was developed using percoll density-gradient centrifugation. gamonts and merozoites were obtained essentially free of host-cell debris. a recovery rate of nearly 30% of the parasites in the original preparations was obtained by this method. merozoites were separated from gamonts by filtration through a 3-micron polycarbonate filter.19979211509
toxoplasmosis: comparative species susceptibility and host immune response.the protozoan parasite toxoplasma gondii is capable of infecting all warm blooded animals; however, the consequences of infection are very variable between different species of animal. marsupials and new world monkeys, which have evolved largely separately from the cat, the definitive host of the parasite, are among the most vulnerable species where infection with t. gondii can prove fatal. in more resistant species such as humans and sheep, infection is generally unapparent, provoking only mild ...19979208198
bradyzoite-specific gene expression in toxoplasma gondii requires minimal genomic elements.bag1 is a small heat-shock protein of toxoplasma gondii that is specifically expressed in the cyst-forming bradyzoite stage of the parasite. upregulation of bag1 mrna occurs early during the differentiation pathway from tachyzoites to bradyzoites. in order define genomic elements involved in bradyzoite-specific gene regulation, chloramphenicol acetyltransferase (cat)-reporter gene studies were performed with 5' flanking sequences of the bag1 gene. tachyzoites, transiently transfected with the ba ...19979108551
toxoplasma pneumonia.toxoplasma gondii, an obligate intracellular parasite, is the causal agent of significant morbidity and mortality worldwide. in the presence of a normal immune response, the pathogen becomes latent and the immunocompetent host remains chronically infected throughout life, often without clinical disease. in the case of the patient with the acquired immunodeficiency syndrome (aids) or other defects in cell-mediated immunity, the infection reactivates and is most often manifest as toxoplasmic encep ...19979097375
long-term humoral antibody responses by various serologic tests in pigs orally inoculated with oocysts of four strains of toxoplasma gondii.antibody titers to toxoplasma gondii were determined in 16 pigs orally inoculated with 1000 or 10,000 oocysts of one of the four strains (gt-1, me-49, ts-2, tc-2) of t. gondii. pigs were euthanized on postinoculation days 103-875 and their tissues were bioassayed for t. gondii. antibody titers were measured in the modified agglutination test (mat) using formalin-preserved (test a) or acetone-preserved (test b) tachyzoites, latex agglutination test (lat), indirect hemagglutination test (iha), enz ...19979066050
cytologic identification of toxoplasma gondii in bronchoalveolar lavage fluid of experimentally infected cats.to determine whether it was possible to retrieve organisms, by means of bronchoalveolar lavage (bal), from cats inoculated with toxoplasma gondii.19979054992
neospora caninum: role for immune cytokines in host immunity.neospora caninum is a coccidial protozoan parasite that infects a large range of mammals including dogs, cats, mice, and cattle. morphologically, n. caninum appears indistinguishable from toxoplasma gondii, although they are genetically distinct. to date there have been no reported cases of this infection in humans, although nonhuman primates may be susceptible to infection. inbred a/j mice develop no clinical and little histologic evidence of infection in spite of a high-dose inoculum of n. can ...19979024199
toxoplasma gondii expresses two distinct lactate dehydrogenase homologous genes during its life cycle in intermediate hosts.two toxoplasma gondii genes were characterized that are differentially expressed during the parasite's life cycle. the genes named ldh1 and ldh2, respectively, encode polypeptides similar to the enzyme lactate dehydrogenase (ldh; l-lactate:nad+ oxidoreductase, ec 1.1.1.27) from a variety of organisms. they show 64.0% nucleotide identity in the coding region and both have an intron at the same relative position. the deduced amino acid sequences of ldh1 and ldh2 share 71.1% identity. ldh1 and ldh2 ...19979016946
feline ocular and cerebrospinal fluid toxoplasma gondii-specific humoral immune responses following specific and nonspecific immune stimulation.toxoplasma gondii-naive cats and cats previously infected orally with t. gondii tissue cysts were inoculated with soluble tachyzoite antigens plus adjuvant or adjuvant alone. toxoplasma gondii-specific igm and igg were measured in serum, aqueous humor, and cerebrospinal fluid (csf). the goldman-witmer coefficient (c value) for ocular or central nervous system (cns) antibody production was calculated for aqueous humor or csf samples positive for t. gondii-specific antibodies. following inoculatio ...19969014303
toxoplasma gondii: experimental infection in cats vaccinated with 60co-irradiated tachyzoites.the effects of 60co-irradiation on the viability and immunogenicity of rh and beverley strains of toxoplasma gondii was examined. while 60co-irradiated tachyzoites retained invasive activity in mouse embryonal cells and sustained antigenicity in mouse peritoneal macrophages, the parasites did not develop in host cells. vaccination of mice with 60co-irradiated tachyzoites of either rh or beverley strains induced resistance to challenge with a highly virulent strain (rh strain). vaccination of kit ...19968983144
diagnostic evaluation of cats with seizure disorders: 30 cases (1991-1993).to investigate causes of seizure disorders in cats.19978977651
infectivity and pathogenicity of toxoplasma gondii oocysts for cats.toxoplasma gondii oocysts are highly infective to intermediate hosts including humans, pigs, and mice, but are considered less infective for cats, the definitive host. to determine infectivity of t. gondii oocysts for cats, 20 2- to 3-mo-old t. gondii-free cats in groups of 4 were fed graded doses of oocysts estimated to have 1, 10, 100, 1,000, or 10,000 mouse infective oocysts of the veg strain of t. gondii. feces of cats were examined for at least 35 days after feeding oocysts. all cats were k ...19968973406
antibody responses measured by various serologic tests in pigs orally inoculated with low numbers of toxoplasma gondii oocysts.to follow antibody responses measured by various serologic tests in pigs orally inoculated with low (< or = 10 oocysts) numbers of toxoplasma gondii oocysts.19968950427
polymerase chain reaction for the detection of toxoplasma gondii in aqueous humor of cats.to develop toxoplasma gondii b1 gene polymerase chain reaction (pcr) for use with aqueous humor of cats, and to report pcr and antibody detection results in naturally exposed cats with and without uveitis.19968915435
strategies to reduce transmission of toxoplasma gondii to animals and humans.toxoplasma gondii is found in the tissues of food animals and is an important cause of abortion and mortality in sheep and goats throughout the world. it causes mental retardation and loss of vision in congenitally infected children and death in immunosuppressed patients. a live vaccine, using a nonpersistent strain of t. gondii, is available in new zealand, the uk and europe which prevents t. gondii abortion in sheep. a live vaccine using a mutant strain of t. gondii (t-263) is being developed ...19968893464
primary and secondary toxoplasma gondii infection in normal and feline immunodeficiency virus-infected cats.normal and asymptomatic feline immunodeficiency virus (fiv)-infected adult cats were inoculated orally with toxoplasma gondii tissue cysts to assess differences in clinical disease, t. gondii serologic test results, hematologic results, and oocyst shedding. there was no difference between fiv-naive and fiv-infected cats in terms of clinical illness and duration of oocyst shedding following primary exposure. both groups of cats developed significant decreases in neutrophil counts following primar ...19968885881
killing of toxoplasma gondii oocysts by irradiation and protective immunity induced by vaccination with irradiated oocysts.toxoplasma gondii oocysts are highly resistant to environmental influences. to study the effect of alpha-irradiation on the viability of t. gondii oocysts, 1 million sporulated oocysts of the veg strain were irradiated to absorbed doses of 0.10, 0.15, 0.20, 0.25, 0.30, 0.40, or 0.50 kgy at 5 c with a 137cs gamma-irradiation source. treated oocysts were bioassayed for viable t. gondii in mice. viable t. gondii was not found in brains of mice 2 mo after oral inoculation with oocysts irradiated at ...19968885879
seroprevalences of brucellosis, q-fever and toxoplasmosis in slaughter livestock in trinidad.serum samples obtained from livestock (cattle, chickens, pigs, sheep, goats and water buffaloes) slaughtered at various slaughter houses in trinidad were screened for agglutinins to three zoonosis causing pathogens. of a total of 751 sera tested, 2 (0.3%) originating from chickens were positive for brucella abortus agglutinins using the rose bengal test (rbt), but both were negative by the tube serum agglutination test (sat). thirty-six (4.8%) of 749 sera were positive for coxiella burnetii aggl ...19968881416
the stage-conversion time of toxoplasma gondii: interpretation of chemical-biologic data out of parasitologic or host context.several published biologic times for the stage conversion of toxoplasma gondii from tachyzoite to bradyzoite in mice are critically examined. there are several reports of 3 days and many of longer times. possible errors, related to delay from dissemination of the infection, are pointed out. the time to the appearance of the 36-kda surface antigen, sometimes used for the diagnosis of bradyzoites, should be compared with the biologic attribute of bradyzoites, inducing the short prepatent period in ...19968875575
toxoplasma gondii antigen recognition by serum immunoglobulins m, g, and a of queens and their neonatally infected kittens.to evaluate antigen recognition patterns of serum igm, igg, and iga from queens and their kittens as a method of diagnosing neonatal toxoplasmosis.19968874728
common cis-acting elements critical for the expression of several genes of toxoplasma gondii.transient transformation of toxoplasma using the cat (chloramphenicol acetyl transferase) reporter gene has been used to map promoter elements of four genes encoding dense granule proteins (gra1, gra2, gra5 and gra6). intense cat activities (gra1 > gra5 > gra2 > gra6) are detected for constructs containing 379bp, 276bp, 209bp and 265bp upstream of the transcription start site of the gra1, gra2, gra5 and gra6 genes, respectively. deletion analysis shows that optimal promoter activity of each gene ...19968858595
epidemiology of toxoplasma gondii in farm ecosystems. 19968822905
irradiation killing of toxoplasma gondii oocysts. 19968822904
chemotherapy of human and animal coccidioses: state and perspectives.the state and perspectives for chemotherapy of cyst-forming and non-cyst-forming coccidia in humans and animals are summarized. in toxoplasmosis the therapeutic care of transplacental infections, which have gone out of control because of immunodeficiency, is in the forefront of attempts at improvement. predominant drugs in use are pyrimethamine combined with a sulfonamide or with clindamycin, or trimethoprim plus sulfamethoxazole. for reasons of tolerability in human immunodeficiency virus (hiv) ...19968801548
co-infection of toxoplasma gondii with other pathogens: pathogenicity and chemotherapy in animal models. 19968791703
an apparent role of dogs in the transmission of toxoplasma gondii. the probable importance of xenosmophilia. 19968784520
lesions of neonatally induced toxoplasmosis in cats.five pregnant queens were inoculated orally with toxoplasma gondii tissue cysts. twenty-two live and three dead kittens were born 16 to 31 days after inoculation. four kittens were eaten by queens and, thus, were not available for histologic examination. twenty-one kittens that died or were euthanatized on day 2 (two kittens), 4 (one kitten), 5 (five kittens), 6 (five kittens), 7 (one kitten), 8 (four kittens), 16 (two kittens), and 29 (one kitten) after birth were studied histologically. t gond ...19968740702
paradoxical effect of clindamycin in experimental, acute toxoplasmosis in cats.cats were experimentally inoculated parenterally with the me49 strain of toxoplasma gondii to characterize the efficacies of two different dosages of orally administered clindamycin hydrochloride in the treatment of ocular toxoplasmosis. concentrations of clindamycin hydrochloride at levels previously suggested to be inhibitory to t. gondii replication in vitro were achieved in the serum and aqueous humor but not in the cerebrospinal fluid. antibiotic therapy, initiated 7 days after inoculation, ...19968726000
complementation of a toxoplasma gondii rop1 knock-out mutant using phleomycin selection.the rop1 gene of toxoplasma gondii encodes a rhoptry protein that has been implicated in host cell invasion by this obligate intracellular protozoan. to further explore the function of this protein, we created a rop1 deletion mutant by transfection with a plasmid encoding the bacterial chloramphenicol acetyltransferase (cat) gene flanked by rop1 genomic sequences. selection for chloramphenicol resistance yielded the desired rop1-deleted or 'knock-out' mutant. analysis of this mutant both in vitr ...19958719248
risk factors for toxoplasma gondii infection in pregnancy. results of a prospective case-control study in norway.from 1992 to 1994, a prospective case-control study designed to identify preventable risk factors for toxoplasma gondii infection in pregnancy was conducted in norway. case-patients were identified through a serologic screening program encompassing 37,000 pregnant women and through sporadic antenatal testing for toxoplasma infection. a total of 63 pregnant women with serologic evidence of recent primary t. gondii infection and 128 seronegative control women matched by age, stage of pregnancy, ex ...19968712198
prevalence of agglutinating antibodies to toxoplasma gondii in small ruminants of the madrid region, spain, and identification of factors influencing seropositivity by multivariate analysis.a seroepidemiological survey of toxoplasma gondii infection in sheep and goats was conducted in the madrid region of spain. sera were collected from 60 herds, for which farming management information and other relevant data for their characterization were also obtained through a questionnaire. the seroprevalence was 11.8% (64 out of 541), using the modified (2-mercaptoethanol) direct agglutination technique with a 1:64 cut-off titre. the relationship between seropositivity and the variables in t ...19968711895
cryopreservation of an attenuated vaccine strain of the protozoan parasite toxoplasma gondii.toxoplasma gondii is a protozoan parasite that infects birds and mammals, including humans. t. gondii t-263 is an attenuated mutant strain that is being developed as a live vaccine to protect cats from shedding oocysts. a cryopreservation procedure for t. gondii t-263 bradyzoites has been developed to meet the requirement for product stability. a me2so-based procedure for the cryopreservation of tachyzoites was used as a basis for process optimization. a modified cell culture plaque assay was us ...19968689890
serologic responses of cattle and other animals infected with neospora caninum.to examine cross-reactivity among neospora caninum and closely-related apicomplexans.19968669764
detection of toxoplasma gondii in feline and canine biological samples by use of the polymerase chain reaction.to develop a polymerase chain reaction (pcr) technique to identify toxoplasma gondii dna in biological samples from cats and dogs.19968669752
[cellular interactions in the intracellular parasitism of cryptosporidia. i. the effect of cryptosporidium parvum on the phosphatase activity in the small intestine enterocytes of experimentally infected newborn rat pups].cytochemical methods for detection of non-specific phosphatases were employed at the light microscope level for identification of enzymatic activity in the small intestine of new-born rats (6--11 days old), both infected and non-infected with the intestinal coccidium cryptosporidium parvum. in the new-born rats, the level of alkaline and especially acid phosphatase is originally very low, suggesting their insignificant involvement in digestion processes in suckling animals compared to rats of ol ...19958669134
incidence of anti-toxoplasma antibodies in women with high-risk pregnancy and habitual abortions.toxoplasmosis is a zoonosis caused by toxoplasma gondii, an obligate intracellular parasite. in pregnant women on the worldwide scale, there are seroprevalences from 7% to 51.3% and in women with abnormal pregnancies and abortions the seroprevalences vary from 17.5% to 52.3%. in mexico, seropositivity has been found to vary from 18.2% to 44.8% in women with abnormal deliveries or abortions. this study's aim was to determine the incidence of igg and igm anti-toxoplasma antibodies in women at the ...19958668832
determination of toxoplasma gondii in organs of naturally infected cattle in costa rica--comment. 19958644455
infectivity of low numbers of toxoplasma gondii oocysts to pigs.to define the infectiousness of the veg strain of toxoplasma gondii, 42 pigs were fed doses estimated at 10, 1, or < 1 mouse infective oocysts. they were killed 38-99 days after inoculation and 50 g of tissues from their tongue, heart, and brain were individually homogenized in acidic pepsin solution and bioassayed in mice. pools of brain, heart, tongue, and skeletal muscle (total 500 g) were bioassayed in cats. toxoplasma gondii was isolated by bioassays in mice and in cats from 13 of 14 pigs f ...19968636849
molecularly cloned feline immunodeficiency virus ncsu1 jsy3 induces immunodeficiency in specific-pathogen-free cats.a full-length feline immunodeficiency virus ncsu1 (fiv-ncsu1) genome (jsy3) was cloned directly from fiv-ncsu1-infected feline cd4+ lymphocyte (fcd4e) genomic dna and identified by pcr amplification with 5' long terminal repeat, gag, env, and 3' long terminal repeat primer sets. supernatant from fcd4e cells cocultured with jsy3-transfected crandell feline kidney (crfk) cells was used as an inoculum. cell-free jsy3 virus was cytopathogenic for fcd4e lymphocytes but did not infect crfk cells in vi ...19968627777
parasite prevalence in free-ranging farm cats, felis silvestris catus.no animals tested were positive for feline leukemia virus antigen and chlamydia psittaci antibodies, but all were positive for antibodies to feline calicivirus (fcv), feline herpesvirus 1 (fhv1) and rotavirus. they had antibodies to feline parvovirus (96%), feline coronavirus (84% and cowpox virus (2%). antibody to feline immunodeficiency virus (fiv) was found in 53% of animals, which were less likely to be infected with haemobartonella felis, and had higher fhv antibody titres than cats without ...19968620914
preventing toxoplasmic encephalitis in persons infected with human immunodeficiency virus.toxoplasmic encephalitis (te) is the second most common aids-related opportunistic infection of the cns. it occurs in 10%-50% of patients with aids who are seropositive for antibodies to toxoplasma gondii and have cd4+ t lymphocyte counts of < 100/mm3. primary toxoplasmic infection usually is acquired by ingestion of t. gondii oocysts from soil contaminated by cat feces or by ingestion of tissue cysts present in undercooked red meats. in patients with aids, te probably results from the reactivat ...19958547512
identification of opossums (didelphis virginiana) as the putative definitive host of sarcocystis neurona.sarcocystis neurona is an apicomplexan that causes equine protozoal myeloencephalitis (epm) in north and south america. horses appear to be an aberrant host, because the merozoites continually divide in the central nervous system, without encysting. the natural host species has not previously been identified. the small subunit ribosomal rna (ssurna) gene of s. neurona was compared to those of sarcocystis muris, sarcocystis cruzi, toxoplasma gondii, and cryptosporidium parvum to identify a unique ...19958544064
long-term antibody responses of cats fed toxoplasma gondii tissue cysts.as part of a long-term study on immunity to oocyst shedding, 12 4-6-mo-old cats were inoculated orally with tissue cysts of the me-49 strain (6 cats) or the ts-2 strain (6 cats) of toxoplasma gondii. two cats fed the me-49 strain died or were killed because of acute toxoplasmosis 12 and 13 days after inoculation (dai), respectively. on day 39 after primary infection, 5 cats (2 infected with the me-49 strain and 3 infected with the ts-2 strain) were challenged orally with tissue cysts of the me-4 ...19958544059
mediation of immunity to toxoplasma gondii oocyst shedding in cats.immunity to toxoplasma gondii, as measured by oocyst shedding, was studied in cats. in 3 trials, 12 3-mo-old t. gondii-free cats were fed tissue cysts of the me-49 strain of t. gondii. all cats shed t. gondii oocysts for approximately 1 wk starting 3-5 days after ingesting tissue cysts. one cat became ill because of toxoplasmic pneumonia and was killed 17 days after inoculation. the remaining cats remained clinically normal. approximately 3 mo after primary infection, these 11 cats (immune) and ...19958544058
concurrent toxoplasmosis and feline infectious peritonitis in a cat.a 13-year-old, 4-kg, neutered male maine coon presented with ascites. toxoplasma gondii tachyzoites were seen within neutrophils and macrophages, and free within the abdominal fluid. at necropsy, many abdominal organs were positive for feline infectious peritonitis (fip) antigens using immunohistochemical staining. this apparently is the first report of concurrent toxoplasmosis and fip in a domestic cat.19958542361
sensitivity and specificity of various serologic tests for detection of toxoplasma gondii infection in naturally infected sows.the sensitivity and specificity of various serologic tests for antibodies to toxoplasma gondii were compared in 1,000 naturally exposed sows, using isolation of viable t gondii as the definitive test. serum samples obtained from heart blood of 1,000 sows from iowa were examined for t gondii antibodies by use of the modified agglutination test (mat), latex agglutination test (lat), indirect hemagglutination test (ihat), and elisa. toxoplasma gondii was isolated from 170 hearts of 1,000 sows by bi ...19958533974
isolation of tissue cysts of toxoplasma, isospora, hammondia and sarcocystis from camel (camelus dromedarius) meat in saudi arabia.meat samples were collected from the oesophagus and tongue of 38 camels slaughtered at the main abattoir of al-ahsa city, saudi arabia. five cats and three dogs, conventionally reared and coccidia-free, were caged individually in steel cages. camel meat was pooled, minced and fed to four cats and two dogs. one cat and one dog were not fed meat and were kept as noninfected controls. faecal samples from infected and control animals were examined daily for a period of 2 months after feeding the mea ...19958533274
detection of toxoplasma gondii antigen-containing immune complexes in the serum of cats.enzyme-linked immunosorbent assays for the detection of toxoplasma gondii antigen-containing igm immune complexes (t gondii-specific igm-ic) and igg immune complexes (t gondii-specific igg-ic) in the serum of cats were developed. serum from clinically ill, naturally infected cats; healthy, naturally infected cats; and healthy cats experimentally inoculated with t gondii was assayed. all combinations of t gondii-specific igm, igg, antigens, igm-ic, and igg-ic were detected in naturally infected a ...19938498745
toxoplasmosis and pregnancy.toxoplasmosis is an infection caused by the protozoa toxoplasma gondii that is prevalent worldwide. the protozoa was given its name when it was first isolated in 1909 in africa in a rodent, ctenodactylus gondii. it can be contracted by eating infected meat or eggs that are raw or undercooked, or through contact with the feces of an infected cat. more dangerously, it can be congenitally acquired by transfer through the placenta if the mother contracts the disease during pregnancy. although the fl ...19938472240
biology of toxoplasma gondii.in conclusion, a large body of new information on the biology and immunology of t. gondii has accumulated in the past several years. much of this is due to the advent of aids and the increased funding made available to researchers interested in opportunistic infections in this patient population. these scientific advances have led to a better understanding of the process by which toxoplasma infects mammalian host cells, molecular biology and biochemistry of the parasite, antigenic structure and ...19938471191
the effect of cobalt-60 irradiation on the infectivity of toxoplasma gondii.toxoplasma gondii cysts in the tissues of experimentally infected mice and pigs were irradiated with cobalt-60 at various doses and used to infect mice and kittens. loss of parasite infectivity was confirmed following irradiation whereas control animals inoculated with non-irradiated infected tissues became infected. experiments were repeated to calculate the minimal effective dose (med) of irradiation to eradicate parasite infectivity. the med for the chinese nt strain and the american me-49 an ...19938468140
neurosurgical management of the acquired immunodeficiency syndrome. an update.a retrospective review of a 24-month experience on the neurosurgical service at a large metropolitan hospital identified 33 patients with the acquired immunodeficiency syndrome (aids) who underwent diagnostic or therapeutic procedures. intracranial mass lesions unresponsive to empiric medical therapy for presumed toxoplasma gondii encephalitis underwent diagnostic biopsy in 22 patients: primary lymphoma was identified in 10 (45%) of these patients, and biopsy led to a treatable diagnosis in 16 o ...19938460506
the prevalence of giardia and other intestinal parasites in children, dogs and cats from aboriginal communities in the kimberley.to determine the prevalence of giardia duodenalis and other intestinal parasites in children, dogs and cats from aboriginal communities in the west kimberley region of western australia.19938450779
unidentified toxoplasma-like tissue cysts in the brains of three cats.tissue cysts of an unidentified toxoplasma-like parasite were found in three of 103 cats that were diagnosed histologically with toxoplasmosis-like illness at the angell memorial animal hospital, boston, ma, between 1952 and 1991. tissue cysts in these three cats were confined to the brain and two cats had concurrent lymphoid disorders. the tissue cysts of the unidentified parasite were about twice the size of toxoplasma gondii tissue cysts.19938447073
sensitive and specific polymerase chain reaction detection of toxoplasma gondii for veterinary and medical diagnosis.a polymerase chain reaction (pcr) method was developed for the detection of toxoplasma gondii. a universal- and a t. gondii-specific primer was used to amplify a region of the small subunit ribosomal rna gene. this approach allows for a theoretical detection limit of 0.01 zoite of t. gondii per sample assayed. experiments showed that this pcr method could detect 0.1 pg of t. gondii dna, which represents about one organism. polymerase chain reaction tests using dnas of cat, dog, swine, cattle, hu ...19938431804
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 recove ...19938430937
feline zoonotic diseases.many of the feline zoonoses occur more frequently in veterinary personnel owing to their direct contact with cats and the potential for exposure to infected body tissue or fluids. infection of humans with afipia felis, yersinia pestis, francisella tularensis, and other aerobic/anaerobic bacteria may cause great discomfort and in some situations terminal illness. although many systemic fungal agents infect humans and cats, only sporothrix schenckii has been shown to infect humans following direct ...19938421889
cats and toxoplasmosis risk in hiv-infected adults.to establish the prevalence and incidence of toxoplasmosis in an adult human immunodeficiency virus (hiv) population, and to determine if cat ownership contributes to the risk of toxoplasmosis.19938416410
immunization of cats with tissue cysts, bradyzoites, and tachyzoites of the t-263 strain of toxoplasma gondii.previous studies have demonstrated that oral administration to cats of tissue cysts of the oocyst-negative mutant strain of toxoplasma gondii, t-263, induces immunity to oocyst shedding following challenge. experiments were designed to compare the levels of protection induced by t. gondii t-263 when tissue cysts, bradyzoites released from tissue cysts, and tachyzoites were administered to cats. in 1 experiment, groups of cats received 2 oral doses of intact tissue cysts or released bradyzoites o ...19938410543
effect of feline immunodeficiency virus infection on toxoplasma gondii-specific humoral and cell-mediated immune responses of cats with serologic evidence of toxoplasmosis.serum samples from 89 cats with serologic evidence of toxoplasmosis were identified by using an enzyme-linked immunosorbent assay (elisa) that detected toxoplasma gondii-specific immunoglobulin m (igm) or t. gondii-specific immunoglobulin g (igg). concurrent feline immunodeficiency virus (fiv) infection was detected in 36 cats using an elisa for detection of fiv-specific igg. the majority of the cats in both the fiv-seropositive and fiv-seronegative groups were male and > 5 years of age. fiv-ser ...19938388954
ribosomal rna sequences for the specific detection of toxoplasma gondii by hybridization assay.we describe the development of five oligonucleotide probes which target the small sub-unit rrna of toxoplasma gondii. these probes bind to different regions within the rrna and all were effective in producing a detectable signal with as little as 10 ng of total cellular rna. one probe in particular, tgb, was able to detect as little as 1 ng of rna and was the most specific. a sixth probe, previously developed for hybridization with sarcocystis spp., was evaluated for its specificity and was show ...19938321257
feline serum antibody responses to toxoplasma gondii and characterization of target antigens.the toxoplasma gondii-specific target antigens for feline immunoglobulin m (igm) and immunoglobulin g (igg) immune responses were studied longitudinally using western blot immunoassay in 8 cats experimentally inoculated with t. gondii strain me49. multiple antigens were recognized by igm and igg during the course of infection. dense bands were associated with 12 antigens in the igm western blot immunoassay and 30 antigens in the igg western blot immunoassay. immunoglobulin m responses were maxim ...19948308661
serological study of human toxoplasmosis in calcutta.a total of 248 randomly selected subjects from urban, semiurban and rural areas of calcutta was studied serologically for the prevalence of antibody to toxoplasma gondii using latex agglutination technique. fifty-nine (23.79%) out of these 248 subjects were found to possess anti-toxoplasma antibody. seropositivity was found to be higher in females (25%) as compared to males (22.32%). agewise highest positivity (30.5%) for toxoplasma antibody was observed in the third decade and lowest in the fir ...19938308306
histologically confirmed clinical toxoplasmosis in cats: 100 cases (1952-1990).tissue sections from 119 cats that died or were euthanatized (1952-1990) because of toxoplasmosis-like illness were reexamined for toxoplasma gondii by direct microscopy and immunohistochemical staining with anti-t gondii serum. clinical and pathologic data from 100 of these cats with histologically verified toxoplasmosis were then analyzed. of these 100 cats, 36 were considered to have generalized toxoplasmosis, 26 predominantly pulmonary lesions, 16 abdominal, 2 hepatic, 1 pancreatic, 1 cardia ...19938288479
neonatal toxoplasmosis in littermate cats.toxoplasmosis was diagnosed histologically in 9 kittens and 1 queen from 5 liters. in litter 1, four 3-month-old siamese kittens and the queen were affected. the queen died of generalized toxoplasmosis, and her kittens died or were euthanatized 20, 22, or 28 days later. in litter 2, two of 3 abyssinian 4- and 4.5-month-old kittens died of toxoplasmosis. in litter 3, an abyssinian, delivered by cesarean section, became ill 17 days after delivery, and died 2 days later because of toxoplasmic hepat ...19938288476
[parasitological fecal studies of equids, dogs, cats and hedgehogs during the years 1984-1991].the results of the coproscopical examinations in horses, dogs, cats and hedgehogs between 1984 and 1991 are presented. in 9192 samples from horses 55.5% stages of strongylids, 4.0% of parascaris equorum, 2.2% of anoplocephalids, 1.6% strongyloides westeri, 0.7% of oxyuris equi, 0.6% of eimeria leuckarti, 0.2% of fasciola hepatica and 0.04% of dictyocaulus arnfieldi were found. in 48.0% of the 46 samples from donkeys eggs from strongylids were detected, in 17.4% larvae from dictyocaulus arnfieldi ...19938261912
a feline model of ocular toxoplasmosis.purpose. this study was performed to characterize the clinical, serologic, histopathologic, and immunohistochemical features of an experimental model of ocular toxoplasmosis in cats.19938258525
seroprevalence of antibodies against toxoplasma gondii among two rural populations in northern israel.the prevalence of antibodies against toxoplasma gondii was measured in two rural populations in northern israel--jewish kibbutz members and arab villagers. the respective prevalences in these two populations were 22.2% and 55.8% (p < 0.001). no correlation was found between the presence of antibodies and sex, occupation, contact with cats, a history of fever and/or lymphadenopathy, eye disease, abortions or delivery of children with congenital malformations. in contrast to jewish children who we ...19938244662
feline immunodeficiency virus predisposes cats to acute generalized toxoplasmosis.this study was designed to examine the effects of a pre-existing, clinically asymptomatic feline immunodeficiency virus (fiv) infection on a primary challenge with toxoplasma gondii. parenteral challenge of fiv-infected cats with tachyzoites of the me49 strain of t. gondii caused a precipitous drop in all lymphocytes (cd4+, cd8+, and b cells) and generalized severe toxoplasmosis. the predominant postmortem lesions included acute and often fatal interstitial pneumonia, dominated histologically by ...19938238262
gene replacement in toxoplasma gondii with chloramphenicol acetyltransferase as selectable marker.a system for stable transformation of toxoplasma gondii tachyzoites was developed that exploited the susceptibility of toxoplasma to chloramphenicol. introduction of the chloramphenicol acetyltransferase (cat) gene fused to toxoplasma flanking sequences followed by chloramphenicol selection resulted in parasites stably expressing cat. a construct incorporating the tandemly repeated gene, b1, targeted efficiently to its homologous chromosomal locus. knockout of the single-copy gene, rop1, was als ...19938235614
[toxoplasmosis epizootic in a fattening swine herd].in a fattening pig herd comprising 80 animals 13 were affected with clinical manifest toxoplasmosis presumably due to cat feces in the food. seven pigs died, one was killed in extremis. the clinical signs were anorexia, apathy, fever, cyanosis, dyspnoea and partly hind limb weakness. one pig that died 3 days after onset of clinical signs had widespread necroses in liver and lymphatic organs. single tachyzoites were detected by immunoperoxidase technique. one pig dying on day 11 and another eutha ...19938223241
[cerebral abscess caused by toxoplasma gondii and aids. report of a case with anatomo-pathological study].we report a 47 year old woman that presented to the hospital with an intracranial hypertension syndrome, a right hemiparesis and a several months history of progressive malaise and behavioral disturbances. during the hospital stay, positive hiv antibodies were detected and cat scan showed a profound left parietal rounded hypodense lesion. the patient died 21 days after admission and the postmortem pathological study showed a deep abscess in the left basal ganglia, with recognizable toxoplasma go ...19938191154
experimental toxoplasmosis in pregnant cats.cysts of the k strain of toxoplasma gondii were administered orally to nine pregnant cats having no antibody to the organism at each of the three stages of gestation, namely early (14 days), middle (30 days), and late (40 and 51 days). premature and weak or deformed fetuses were observed in the offsprings delivered by mother cats infected with toxoplasma in the early or middle stage of gestation, while the cats infected at the late stage were delivered of apparently healthy fetuses. mother cats ...19938117796
toxoplasmosis and mental retardation--report of a case-control study.a case-control study evaluating the association between mental retardation and toxoplasmosis was conducted among 845 school children in belo horizonte, mg, brazil. cases (450) were mentally retarded children attending a public school for special education. controls (395) were children from the regular public school system. clinical and anthropometric examinations and interviews were carried out to determine risk factors for toxoplasmosis and mental retardation. diagnosis of toxoplasma gondii inf ...19938107587
transfer of antibodies to kittens from mother cats chronically infected with toxoplasma gondii.by indirect immunofluorescence assay, anti-toxoplasma gondii antibody levels were examined in fetuses and kittens born from chronically infected cats. titer of anti-t. gondii igg in sera of kittens born from infected cats was significantly high on the seventh day post-birth, and decreased to a serologically non-detectable level at 8-12 weeks post-birth under continuous suckling of maternal milk. littermates nursed by a non-infected cat showed a faster rate of igg antibody depletion. in sera of f ...19948073605
epidemiologic observations on infection with rochalimaea species among cats living in baltimore, md.cats from several sources in baltimore, md, were tested for seropositivity to rochalimaea henselae and r quintana. co-infection with toxoplasma gondii or feline immunodeficiency virus was assessed as a risk factor for infection with rochalimaea spp. of 592 cats tested, 87 (14.7%) were seropositive for one or both rochalimaea spp, although titers to r henselae were significantly higher than those to r quintana. prevalence of seropositivity increased significantly with cat age and weight and was a ...19948063598
effect of toxoplasma gondii upon neophobic behaviour in wild brown rats, rattus norvegicus.the effect of toxoplasma gondii on neophobic behaviour (the avoidance of novel stimuli) was assessed in four groups of wild rats with naturally occurring toxoplasma infection. two groups were placed in individual cages and tested in a series of experiments which examined the effect of toxoplasma on the rat's reaction to 3 food-related novel stimuli (odour, food-container, food). a trappability study was performed on the other two groups to test whether toxoplasma had an effect on probability of ...19948058367
elisas based on recombinant antigens for seroepidemiological studies on toxoplasma gondii infections in cats.two recombinant toxoplasma gondii polypeptides, h4 and h11, were tested as diagnostic antigens in enzyme-linked immunosorbent assays (elisas). the results obtained by elisas based on single h4 (h4-elisa), on single h11 (h11-elisa) and on a mixture of h4 and h11 (h4/h11-elisa) were compared with results obtained by an elisa based on traditional elisa antigen (tea-elisa), an indirect fluorescent antibody test (ifat), the sabin-feldman dye test (sfdt) and a direct agglutination test (dat). a total ...19948058366
serologic survey and serum biochemical reference ranges of the free-ranging mountain lion (felis concolor) in california.serum samples from 58 mountain lions (felis concolor) in california (usa) were collected between april 1987 and february 1990. nineteen serum samples were used for serum biochemistry determinations; the ranges were similar to reference values in domestic cats, captive exotic felidae and free-ranging mountain lions. a serological survey was conducted to determine whether antibodies were present against selected infectious agents. fifty-four (93%) of 58 sera had antibodies against feline panleukop ...19948028105
prevalence and transmission of toxoplasma gondii in wild brown rats, rattus norvegicus.prevalence of toxoplasma gondii within 6 uk farmstead wild rat populations, and 1 population maintained within a captive cat-free environment for 2.5 years, was examined. the mean prevalence found was 35% (n = 235), which is more than 3 times as high as all other wild rat prevalence levels previously reported in the uk. there were no significant age, sex or site differences in prevalence between or within populations irrespective of habitat type or presence of cats. toxoplasma was also maintaine ...19948008454
characterization of toxoplasma and trichinella isolates from muscles of black bears in pennsylvania.during the hunting season of 1992, 322 black bears from pennsylvania were examined for toxoplasma gondii- and trichinella spp-induced infections. toxoplasma gondii antibodies were found in 79.8% of 322 bears--titer < 1:25 in 65 (20.2%), 1:25 in 18 (5.6%), 1:50 in 11 (34.5%) and 1:500 in 128 (38.7%) bears--by use of the modified agglutination test. muscle tissues from 89 of these bears were bioassayed for t gondii parasites. muscles from 64 bears, including heart from 1 bear, and heart alone from ...19947944020
evaluation of a direct agglutination test for detection of antibodies against toxoplasma gondii in cat, pig and sheep sera. 19947942387
killing of different strains of toxoplasma gondii tissue cysts by irradiation under defined conditions.to study the effect of gamma-irradiation on the viability of toxoplasma gondii tissue cysts, brains of mice inoculated with 95 newly isolated strains of t. gondii from pigs and 10 other laboratory isolates were pooled, flattened, packed in vacuum, and irradiated to absorbed doses of 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, and 0.9 kgy at 5 c (+/- 0.5 c) with a 137cs gamma-radiation source. treated samples were bioassayed for viable t. gondii in mice, cats, or both. tissue cysts of all strains were ren ...19947931910
effects of incidental infections and immune activation on disease progression in experimentally feline immunodeficiency virus-infected cats.specific pathogen-free cats were experimentally infected with feline immunodeficiency virus (fiv) and subsequently exposed to common infectious pathogens and immune stimuli over a 3-year period. cats with preexisting fiv infection showed signs of disease after exposure to haemobartonella felis, toxoplasma gondii, feline herpesvirus-1, and feline calicivirus similar to signs in non-fiv-infected cats, although they were more severe. no adverse effects of immunization with inactivated rabies virus ...19947916048
fatal toxoplasmosis in five cats.fatal toxoplasmosis was diagnosed in five of 155 cats necropsied in denmark during a 2 year period, thus representing 3.2% of the necropsied animals. lesions were dominated by scattered necrotic foci in liver and spleen. toxoplasma gondii was demonstrated primarily by an immunoperoxidase technique. the clinical signs were rhinitis, conjunctivitis, dyspnoea and neurological malfunction. the relatively high prevalence indicates that clinical and fatal toxoplasmosis, naturally acquired, seems more ...19947886915
toxoplasma gondii in iowa sows: comparison of antibody titers to isolation of t. gondii by bioassays in mice and cats.hearts of 1,000 pigs killed at an abattoir in iowa were bioassayed for the prevalence of tissue cysts of toxoplasma gondii. one hundred grams of cardiac muscle from each pig was homogenized, digested in pepsin solution, and bioassayed in 10 mice. five hundred grams of heart tissue from each of a subset of 183 pigs was also bioassayed in cats. serum collected from the heart from each pig was assayed for anti-t. gondii antibodies in the modified agglutination test using formalin-fixed whole tachyz ...19957876977
prevalence of viable toxoplasma gondii tissue cysts and antibodies to t. gondii by various serologic tests in black bears (ursus americanus) from pennsylvania.during the hunting season of 1993, hearts from 28 black bears (ursus americanus) from pennsylvania were examined for toxoplasma gondii infection. serum samples from heart blood were examined for t. gondii antibodies by the use of the modified agglutination test (mat), the sabin-feldman dye test (dt), the latex agglutination test (lat), and the indirect hemagglutination test (iha). one-hundred grams of myocardium from each bear were bioassayed in mice. approximately 500 g of myocardium from 11 be ...19957876963
congenital toxoplasmosis among premature infants with different clinical pictures in saudi arabia.no doubt, toxoplasmosis is a prevalent infection in all the arab countries. however, the incidence differs from one country to another and even within the same country. congenital toxoplasmosis is the most important form of the infection. in the present study, some 78 premature infants with different clinical pictures were examined for toxoplasma igg (by ihat and elisa) and toxoplasma igm (by elisa). the results showed toxoplasma igg ranging between 32.1% (ihat) and 46.2% (elisa) while igm (elis ...19947844430
the effect of toxoplasma gondii and other parasites on activity levels in wild and hybrid rattus norvegicus.using both correlational and experimental evidence, the relationship between parasite load and host activity was assessed in brown rats, rattus norvegicus. two hypotheses were tested--(1) that parasites with indirect life-cycles, involving transmission between a prey and its predator, will alter the activity of the intermediate host so as to increase its susceptibility to predation by the definitive host and (2) that activity levels in parasitized rats would be increased rather than decreased. f ...19947831094
safety aspects of a vaccine for cats containing a toxoplasma gondii mutant strain. 19947804276
tissue cyst formation of toxoplasma gondii t-263 in cell culture. 19947804222
toxoplasma gondii-specific antibodies in the aqueous humor of cats with toxoplasmosis.we decided to determine whether toxoplasma gondii-specific igm or igg is produced locally or is deposited in the aqueous humor of t gondii-naive cats after primary or secondary inoculation with t gondii. cats were orally inoculated with t gondii tissue cysts during weeks 0 and 36. aqueous humor and serum t gondii-specific igm and igg were measured, using elisa, during weeks 0, 2, 4, 6, 8, 12, 16, 20, 26, 34, 38, 40, 42, 44, 48, 56, 62, 66, and 72 after primary oral inoculation. total immunoglobu ...19947802391
phylogenetic relationship of sarcocystis neurona to other members of the family sarcocystidae based on small subunit ribosomal rna gene sequence.sarcocystis neurona is a coccidial parasite that causes a neurologic disease of horses in north and south america. the natural host species are not known and classification is based on ultrastructural analysis. the small subunit ribosomal rna (ssurna) gene of s. neurona was amplified using polymerase chain reaction techniques and sequenced by sanger sequencing reactions. the sequence was compared with partial sequences of s. muris, s. gigantea, s. tenella, s. cruzi, s. arieticanis, s. capracanis ...19947799170
safety and efficacy of modified live feline toxoplasma gondii vaccine. 19957796964
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