Ocular Findings in Infants with Congenital Toxoplasmosis after a Toxoplasmosis Outbreak.

PURPOSE: We investigated the prevalence of ocular abnormalities in infants vertically exposed to Toxoplasma gondii infection during an outbreak in Santa Maria City, Brazil. DESIGN: Consecutive case series. PARTICIPANTS: A total of 187 infants were included. METHODS: The infants were recruited from January 2018 to November 2019. All mothers were screened for syphilis and human immunodeficiency virus before delivery. Toxoplasmosis infection was confirmed in all mothers and infants based on the presence of serum anti-T. gondii immunoglobulin G (IgG) and immunoglobulin M (IgM) antibodies. All infants underwent an ophthalmologic examination; ocular abnormalities were documented using a wide-field digital imaging system. Neonatal cranial sonography or head computed tomography was performed in 181 infants, and the cerebrospinal fluid (CSF) was screened for anti-T. gondii IgG and IgM antibodies in 159 infants. Peripheral blood samples from 9 infants and their mothers were analyzed for the presence of T. gondii DNA by real-time polymerase chain reaction. MAIN OUTCOME MEASURES: Ocular abnormalities associated with congenital toxoplasmosis. RESULTS: A total of 187 infants were examined. Twenty-nine infants (15.5%) had congenital toxoplasmosis, of whom 19 (10.2%) had ocular abnormalities, including retinochoroiditis in 29 of 38 eyes (76.3%), optic nerve abnormalities in 5 eyes (13.2%), microphthalmia in 1 eye (2.6%), and cataract in 2 eyes (5.3%). Bilateral retinal choroidal lesions were found in 10 of 19 infants (52.6%). Nine eyes of 6 infants had active lesions, with retinal choroidal cellular infiltrates at the first examination. Thirteen (7.2%) of 181 infants screened presented with cerebral calcifications. Eighty-three percent of the screened infants were positive for anti-T. gondii IgG and negative for IgM antibodies in the CSF. Congenital toxoplasmosis was higher in mothers infected during the third pregnancy trimester, and maternal treatment during pregnancy was not associated with a lower rate of congenital toxoplasmosis. CONCLUSIONS: High prevalence rates of clinical manifestations were observed in infants with congenital toxoplasmosis after a waterborne toxoplasmosis outbreak, the largest yet described. Cerebral calcifications were higher in infants with ocular abnormalities, and maternal infection during the third pregnancy trimester was associated with a higher rate of congenital toxoplasmosis independent of maternal treatment.

[IMPROVEMENT OF ETIOLOGICAL DIAGNOSIS OF THE CEREBRAL TOXOPLASMOSIS IN HIV-INFECTED PERSONS].

The objective of the study was to determine the diagnostic value of the parallel detection of the avidity index of the IgG to Toxoplasma gondii in the blood and cerebrospinal fluid by a three-step solid-phase enzyme immunoassay using T. gondii antigen, protein dissociating agent and monoclonal antibodies against human IgG at HIV-infected individuals with a focal damage of the brain. The results of the study showed that conducting of the enzyme-linked immunosorbent assay by a direct and dissociated method makes it possible to detect specific intrathecal and serum immunoglobulins, which is proposed in terms of improving diagnosis of cerebral toxoplasmosis in HIV-infected individuals. The high informative ability of the test system for detecting the avidity index of IgG antibodies to T. gondii allows the possibility to apply it in the algorithm for diagnosing an etiological factor of neuroinfection in HIV-infected individuals.

Toxoplasma gondii seroprevalence and association with equine protozoal myeloencephalitis: A case-control study of Californian horses.

While toxoplasmosis is not commonly considered a clinical disease of equines, previous seroprevalence studies have reported differing background rates of Toxoplasma gondii infection in horses globally. The objective of this study was to evaluate possible associations between T. gondii seroprevalence and clinical signs of equine protozoal myeloencephalitis (EPM) in horses. Using a case-control study design, 720 Californian horses with neurologic signs compatible with EPM were compared to healthy, non-neurologic horses for the presence of T. gondii antibodies (using indirect fluorescent antibody tests [IFAT]). Toxoplasma gondii seroprevalence among cases and controls was determined at standard serum cut-offs: 40, 80, 160, 320, and 640. At a T. gondii titre cut-off of 320, horses with clinical signs compatible with EPM had 3.55 times the odds of a seropositive test compared to those without clinical signs (P<0.01) when adjusted for covariates. When restricted to the autumn season and at the same titre cut-off, an EPM suspect horse had 6.4 times the odds of testing seropositive to T. gondii, compared to non-neurologic horses. The association between high T. gondii titres and clinical signs compatible with EPM is potentially reflective of toxoplasmosis in equines. Serologic testing of cerebrospinal fluid and isolation of T. gondii in EPM suspect cases should be considered. Future studies investigating the relationship between T. gondii and EPM are warranted.

Toxoplasma-SPECIFIC IgG SUBCLASS ANTIBODY RESPONSE IN CEREBROSPINAL FLUID SAMPLES FROM PATIENTS WITH CEREBRAL TOXOPLASMOSIS.

Cerebral toxoplasmosis can be highly debilitating and occasionally fatal in persons with immune system deficiencies. In this study, we evaluated the Toxoplasma gondii-specific IgG subclass antibody response in 19 cerebrospinal fluid (CSF) samples from patients with cerebral toxoplasmosis who had a positive IgG anti-T. gondii ELISA standardized with a cyst antigen preparation. There were no significant differences between the rates of positivity and the antibody concentrations (arithmetic means of the ELISA absorbances, MEA) for IgG1 and IgG2, but the rates of positivity and MEA values for these two IgG subclasses were significantly higher than those for IgG3 and IgG4. The marked IgG2 response in CSF from patients with cerebral toxoplasmosis merits further investigation.

Blood-brain barrier disruption during spontaneous canine visceral leishmaniasis.

Visceral leishmaniasis is a complex disease caused by Leishmania infantum, and in dogs, besides the classical symptoms, there are descriptions of inflammatory alterations in the brain. Brain inflammation is a strictly controlled process, and as the brain counts on the efficiency of the blood-brain barrier (BBB), we aimed to assess BBB integrity in dogs with spontaneous visceral leishmaniasis. Therefore, we evaluated markers in the cerebrospinal fluid (CSF) and in brain tissue related to BBB disruption and brain inflammation. Elevated albumin quota revealed BBB breakdown, corroborated by increased concentrations of anti-Leishmania antibodies in the CSF. In the brain, albumin and IgG staining formed halos around blood vessels, a classical indicator of BBB leakage. Soluble IgG was also detected in the choroid plexus and ependyma, and in these structures, IgG stained random resident cells. IgG(+) cells and Fcγ-RI(+) cells were identified in the choroid plexus, ependyma and perivascular in the brain parenchyma. The data support the occurrence of BBB disruption in dogs with spontaneous visceral leishmaniasis, and IgG as a key molecule that is capable of initiating and/or maintaining the inflammatory stimuli in the nervous milieu and the CSF as an important disseminator of inflammatory stimuli within the CNS.

An observational study of inflammation in the central nervous system in patients with bipolar disorder.

OBJECTIVES: The potential influence of infections and immunological changes on the aetiology and pathogenesis of bipolar disorder (BD) has been discussed. Our aim was to detect intrathecal specific antibody synthesis against the neurotropic infectious agents that have previously been linked to BD. METHODS: Paired cerebrospinal fluid (CSF) and serum samples from 40 patients with BD were analysed using the enzyme-linked immunosorbent assay to detect the concentration of antibodies against the following neurotropic infectious pathogens: Toxoplasma gondii (T. gondii), herpes simplex virus (HSV) types 1 and 2, cytomegalovirus (CMV), and Epstein-Barr virus (EBV). The specific antibody index (AI) was calculated, and an AI > 1.4 was considered to be evidence of intrathecal specific antibody synthesis. Twenty-six patients with pseudotumour cerebri served as controls. RESULTS: Eight out of 40 patients with BD displayed specific intrathecal antibody synthesis against at least one of the tested neurotropic agents compared to only one patient in the control group (p = 0.061, not significant). Of these eight patients with BD, no significant prevalence of any particular neurotropic pathogen was evident. Five out of 40 patients with BD showed oligoclonal bands in the CSF, suggestive of a chronic immune reaction in the central nervous system (CNS). CONCLUSIONS: We found evidence for increased production of antibody in the CSF of individuals with BD. However, the trend for polyspecific intrathecal antibody synthesis, as well as the presence of oligoclonal bands, might indicate activation of the intrathecal humoral immune system in a subgroup of patients with BD, as it is known to be associated with autoimmune disorders of the CNS.

Acute onset of encephalomyelitis with atypical lesions associated with dual infection of Sarcocystis neurona and Toxoplasma gondii in a dog.

A two-year-old male, neutered, basset hound-beagle mix with progressive neurological impairment was examined postmortem. Grossly, the dog had multiple raised masses on the spinal cord between nerve roots. Microscopically, the dog had protozoal myeloencephalitis. Toxoplasma gondii and Sarcocystis neurona were detected in the CNS by immunohistochemistry and polymerase chain reaction (PCR). Sarcocysts in formalin-fixed muscle were negative for Sarcocystis by PCR. Banked serum was negative for T. gondii using the modified agglutination test, suggesting an acute case of T. gondii infection or immunosuppression; however, no predisposing immunosuppressive diseases, including canine distemper, were found. To the authors' knowledge, this is the first report of dual T. gondii and S. neurona infection in a dog.

Cerebral toxoplasmosis after umbilical cord blood transplantation diagnosed by the detection of anti-toxoplasma specific IgM antibody in cerebrospinal fluid.

Cerebral toxoplasmosis is a rare, potentially fatal, complication of hematopoietic cell transplantation. Early definitive diagnosis is very difficult and it may be associated with a poor prognosis. Herein, we describe a 60-year-old woman who developed cerebral toxoplasmosis after cord blood transplantation for myelodysplastic syndrome. During treatment with tacrolimus and methylprednisolone for relapsed grade 2 acute gut GVHD, fever and disturbance of consciousness occurred on day 210. Brain MRI showed multiple ring-enhancing nodular lesions in the thalamus, basal ganglia, brainstem, and subcortical white matter. Cerebrospinal fluid (CSF) assessment revealed elevations of both anti-to-xoplasma IgM and IgG, which were also elevated in serum, but no evidence of other infections or malignancies. Notably, the IgM level was higher in the CSF than in serum. Thus, cerebral toxoplasmosis was diagnosed. Soon after administration of oral sulfamethoxazole/trimethoprim and intravenous clindamycin in combination with short-term dexamethasone for the cerebral edema, her symptoms and signs began to improve. On day 229, both IgM and IgG titers in CSF had clearly decreased but remained essentially constant in serum. She was discharged without clinically significant neurological disorders. This case suggests that CSF specific anti-toxoplasma IgM titers might be useful for early diagnosis of cerebral toxoplasmosis after transplantation.

Cyclical appearance of African trypanosomes in the cerebrospinal fluid: new insights in how trypanosomes enter the CNS.

It is textbook knowledge that human infective forms of Trypanosoma brucei, the causative agent of sleeping sickness, enter the brain across the blood-brain barrier after an initial phase of weeks (rhodesiense) or months (gambiense) in blood. Based on our results using an animal model, both statements seem questionable. As we and others have shown, the first infection relevant crossing of the blood brain border occurs via the choroid plexus, i.e. via the blood-CSF barrier. In addition, counting trypanosomes in blood-free CSF obtained by an atlanto-occipital access revealed a cyclical infection in CSF that was directly correlated to the trypanosome density in blood infection. We also obtained conclusive evidence of organ infiltration, since parasites were detected in tissues outside the blood vessels in heart, spleen, liver, eye, testis, epididymis, and especially between the cell layers of the pia mater including the Virchow-Robin space. Interestingly, in all organs except pia mater, heart and testis, trypanosomes showed either a more or less degraded appearance of cell integrity by loss of the surface coat (VSG), loss of the microtubular cytoskeleton and loss of the intracellular content, or where taken up by phagocytes and degraded intracellularly within lysosomes. This is also true for trypanosomes placed intrathecally into the brain parenchyma using a stereotactic device. We propose a different model of brain infection that is in accordance with our observations and with well-established facts about the development of sleeping sickness.

TLTF in cerebrospinal fluid for detection and staging of T. b. gambiense infection.

BACKGROUND: Trypanosome-derived lymphocyte triggering factor (TLTF) is a molecule released by African trypanosomes that interacts with the host immune system, resulting in increased levels of IFN-γ production. METHODOLOGY/PRINCIPAL FINDINGS: TLTF and anti-TLTF antibodies were assessed in sera and cerebrospinal fluid (CSF) from patients infected with Trypanosoma brucei gambiense (T. b. gambiense) in an attempt to identify alternative markers for diagnosis and stage determination of human African trypanosomiasis or sleeping sickness. Seventy-four serum and sixty-one CSF samples from patients with parasitologically confirmed infection and known disease stage along with 13 sera and CSF from uninfected controls were tested. In serum the levels of anti-TLTF antibodies were unrelated to the disease stage. In contrast, levels of anti-TLTF antibodies in CSF were higher in intermediate/late stages than in early stage disease patients. Specificity of the detected antibodies was assessed by inhibition of TLTF bioactivity as represented by its ability to induce IFN-γ production. Additionally, TLTF was detected in CSF from late stage patients by Western blotting with the anti-TLTF specific monoclonal antibody MO3. CONCLUSIONS/SIGNIFICANCE: These findings suggest a new possibility for disease diagnosis with focus on involvement of the CNS through detection of TLTF and anti-TLTF antibodies in the CSF.

Accurate antemortem diagnosis of equine protozoal myeloencephalitis (EPM) based on detecting intrathecal antibodies against Sarcocystis neurona using the SnSAG2 and SnSAG4/3 ELISAs.

BACKGROUND: Recent work demonstrated the value of antigen-specific antibody indices (AI and C-value) to detect intrathecal antibody production against Sarcocystis neurona for antemortem diagnosis of equine protozoal myeloencephalitis (EPM). OBJECTIVES: The study was conducted to assess whether the antigen-specific antibody indices can be reduced to a simple serum : cerebrospinal fluid (CSF) titer ratio to achieve accurate EPM diagnosis. ANIMALS: Paired serum and CSF samples from 128 horses diagnosed by postmortem examination. The sample set included 44 EPM cases, 35 cervical-vertebral malformation (CVM) cases, 39 neurologic cases other than EPM or CVM, and 10 non-neurologic cases. METHODS: Antibodies against S. neurona were measured in serum and CSF pairs using the SnSAG2 and SnSAG4/3 (SnSAG2, 4/3) ELISAs, and the ratio of each respective serum titer to CSF titer was determined. Likelihood ratios and diagnostic sensitivity and specificity were calculated based on serum titers, CSF titers, and serum : CSF titer ratios. RESULTS: Excellent diagnostic sensitivity and specificity was obtained from the SnSAG2, 4/3 serum : CSF titer ratio. Sensitivity and specificity of 93.2 and 81.1%, respectively, were achieved using a ratio cutoff of ≤100, whereas sensitivity and specificity were 86.4 and 95.9%, respectively, if a more rigorous cutoff of ≤50 was used. Antibody titers in CSF also provided good diagnostic accuracy. Serum antibody titers alone yielded much lower sensitivity and specificity. CONCLUSIONS AND CLINICAL IMPORTANCE: The study confirms the value of detecting intrathecal antibody production for antemortem diagnosis of EPM, and they further show that the antigen-specific antibody indices can be reduced in practice to a simple serum : CSF titer ratio.

IgG4 specific to Toxoplasma gondii excretory/secretory antigens in serum and/or cerebrospinal fluid support the cerebral toxoplasmosis diagnosis in HIV-infected patients.

Cerebral toxoplasmosis is the most common neurological opportunistic disease manifested in HIV infected patients. Excretory/secretory antigens (ESA) are serological markers for the diagnosis of reactivation of the infection in HIV-infected patients with cerebral toxoplasmosis. Immunosuppressed patients develop high antibody titers for ESA. However, little is known about the humoral response for these antigens. The present study analyzed the profile of antibody recognition against ESA in comparison with tachyzoite lysate antigen (TLA) in 265 sera and 270 cerebrospinal fluid (CSF) samples from infected patients with Toxoplasma gondii and or HIV and in sera of 50 healthy individuals. The samples of sera and CSF were organized in 8 groups. The sera sample groups were: Group I - Se/CT/AIDS (patients with cerebral toxoplasmosis/AIDS) with 58 samples; Group II - Se/ONinf/AIDS/PosT (patients with AIDS/other neuroinfections/positive toxoplasmosis) with 49 samples; Group III - Se/ONinf/AIDS/NegT (patients with AIDS/other neuroinfections/negative toxoplasmosis) with 58 samples; Group IV - Se/PosT/NegHIV (individuals with asymptomatic toxoplasmosis/negative HIV) with 50 samples and Group V - Se/NegT/NegHIV (healthy individuals/negative toxoplasmosis and HIV) with 50 samples. The CSF sample groups were: Group VI - CSF/CT/AIDS (patients with cerebral toxoplasmosis/AIDS) with 99 samples; Group VII - CSF/ONinf/AIDS/PosT (patients with AIDS/other neuroinfections/positive toxoplasmosis) with 112 samples, and Group VIII - CSF/ONinf/AIDS/NegT (patients with AIDS/other neuroinfections/negative toxoplasmosis) with 59 samples. Levels of IgM, IgA, IgE, IgG and subclasses were determined by ELISA against TLA and ESA antigens. IgM, IgA or IgE antibodies against ESA or TLA were not detected in sera from patients with toxoplasmosis suggesting that all patients were in chronic phase of the infection. High levels of IgG1 against TLA were found in sera samples from groups I, II and IV and in CSF samples from groups VI and VII; whereas IgG2, IgG3 and IgG4 levels were not detected in the same sera or CSF sample groups. However, patients from groups I and VI, that had tachyzoites circulating in blood and CSF respectively, produced a mix of IgG1 and IgG4 antibodies against ESA. IgG2 against ESA were predominant in serum from patients with the latent (non-active) T. gondii infection/HIV negative and in CSF samples from patients with other neuroinfections and positive toxoplasmosis (groups IV and VII, respectively). IgG4 levels against ESA were found to be significantly (P<0.05 and P<0.005) higher in patients with cerebral toxoplasmosis (groups I and VI, respectively) in comparison with groups II, IV and VII. This data suggest that IgG4 can be valuable for supporting the diagnosis of focal brain lesions, caused by T. gondii infection, in HIV-infected patients. This approach might be useful, mainly when molecular investigation to detect parasites is not available.

Isolation of Toxoplasma gondii strains similar to Africa 1 genotype in Turkey.

INTRODUCTION: Toxoplasma gondii is a protozoon parasite that has a worldwide dissemination. It can cause serious clinical problems such as congenital toxoplasmosis, retinochoroiditis, and encephalitis. Currently, T. gondii genotypes are being associated with these clinical presentations which may help clinicians design their treatment strategy. CASE REPORTS: Two T. gondii strains named Ankara and Ege-1 were isolated from newborns with congenital toxoplasmosis in Central and Western Anatolia, respectively. Ankara and Ege-1 strains were isolated from the cerebrospinal fluid of newborns. According to microsatellite analysis, Ankara and Ege-1 strains were sorted as Africa 1 genotype. CONCLUSION: T. gondii strains isolated in Turkey were first time genotyped in this study. Africa 1 genotype has previously been isolated in immunosuppressed patients originating from sub-Saharan Africa. The reason of detecting a strain mainly detected in Africa can be associated with Turkey's specific geographical location. Turkey is like a bridge between Asia, Europe and Africa. Historically, Anatolia was on the Silk Road and other trading routes that ended in Europe. Thus, detecting Africa 1 strain in Anatolia can be anticipated. Consequently, strains detected mainly in Europe and Asia may also be detected in Anatolia and vice versa. Therefore, further studies are required to isolate more strains from Turkey.

[Use of immunological and molecular biological methods to diagnose cerebral toxoplasmosis in HIV infection].

Cerebral toxoplasmosis is one of the leading causes of neurologic diseases with high mortality rates in patients with HIV infection. Invasion was difficult to diagnose for a number of objective reasons. The objective of the investigation was to determine the clinical sensitivity of different laboratory techniques as both a single study and their various combinations to verify the diagnosis of cerebral toxoplasmosis in HIV-infected patients. Blood and cerebrospinal fluid were tested in 51 patients with Stage 4B HIV infection (AIDS) with the verified diagnosis of cerebral toxoplasmosis. Separate determination of specific antibodies of IgG, IgM, IgA and toxoplasma DNA in the blood and cerebrospinal fluid was shown to have an insufficient clinical sensitivity (37.3-68.6%). The benefits of various combinations of immunological and molecular biological assays enhancing the diagnostic efficiency up to 76.5-96.1% are demonstrated.

Stage progression and neurological symptoms in Trypanosoma brucei rhodesiense sleeping sickness: role of the CNS inflammatory response.

BACKGROUND: Human African trypanosomiasis progresses from an early (hemolymphatic) stage, through CNS invasion to the late (meningoencephalitic) stage. In experimental infections disease progression is associated with neuroinflammatory responses and neurological symptoms, but this concept requires evaluation in African trypanosomiasis patients, where correct diagnosis of the disease stage is of critical therapeutic importance. METHODOLOGY/PRINCIPAL FINDINGS: This was a retrospective study on a cohort of 115 T.b.rhodesiense HAT patients recruited in Eastern Uganda. Paired plasma and CSF samples allowed the measurement of peripheral and CNS immunoglobulin and of CSF cytokine synthesis. Cytokine and immunoglobulin expression were evaluated in relation to disease duration, stage progression and neurological symptoms. Neurological symptoms were not related to stage progression (with the exception of moderate coma). Increases in CNS immunoglobulin, IL-10 and TNF-α synthesis were associated with stage progression and were mirrored by a reduction in TGF-ß levels in the CSF. There were no significant associations between CNS immunoglobulin and cytokine production and neurological signs of disease with the exception of moderate coma cases. Within the study group we identified diagnostically early stage cases with no CSF pleocytosis but intrathecal immunoglobulin synthesis and diagnostically late stage cases with marginal CSF pleocytosis and no detectable trypanosomes in the CSF. CONCLUSIONS: Our results demonstrate that there is not a direct linkage between stage progression, neurological signs of infection and neuroinflammatory responses in rhodesiense HAT. Neurological signs are observed in both early and late stages, and while intrathecal immunoglobulin synthesis is associated with neurological signs, these are also observed in cases lacking a CNS inflammatory response. While there is an increase in inflammatory cytokine production with stage progression, this is paralleled by increases in CSF IL-10. As stage diagnostics, the CSF immunoglobulins and cytokines studied do not have sufficient sensitivity to be of clinical value.

Canine Trypanosoma evansi infection introduced into Germany.

A 9-year-old male Jack Russell Terrier with a history of travel to Thailand was presented with chronic lethargy, weight loss, unilateral anterior uveitis, pancytopenia, hyperglobulinemia, and proteinuria. Numerous trypomastigotes were found on a blood smear, and using molecular methods the parasite was identified as Trypanosoma evansi. After initial response to treatment, the dog experienced a relapse with central neurologic signs 88 days after initial presentation and died. Antibodies to T evansi were detected in both serum and cerebrospinal fluid (CSF) using a card agglutination test (CATT/T evansi), and PCR analysis of CSF for T evansi was positive. Findings at necropsy included marked non-purulent meningoencephalitis. Chronic infection with T evansi in a dog that returned to Germany following international travel highlights the risk associated with introduction of foreign animal diseases to Europe and the possibility of these infections becoming endemic. Detection of chronic infection and curative therapy of trypanosomiasis are challenging, and infection is usually fatal in the dog.

Glial reactivity in dogs with visceral leishmaniasis: correlation with T lymphocyte infiltration and with cerebrospinal fluid anti-Leishmania antibody titres.

Visceral leishmaniasis is a multisystemic zoonotic disease that can manifest with several symptoms, including neurological disorders. Because glial cells are extensively associated with the immune response within the brain, we evaluated the morphology of astrocytes and microglia of dogs naturally infected with Leishmania chagasi. We used immunohistochemical and lectin-histochemical techniques for morphological analyses and we also examined the glial correlation with lymphocyte infiltration of the brain and with the presence of anti-Leishmania antibodies within the cerebrospinal fluid of the dogs. Although we did not detect a shared morphological pattern in the astrocytes or microglia in the brain tissue, these cells were more intensely labelled in infected dogs than in the control group. The density of microglia was increased in the ependymal/subependymal area, thus demonstrating a strong correlation with the presence of T lymphocytes and with cerebrospinal fluid antibody titres. Thus, our results indicate a pro-inflammatory state in the brains of dogs naturally infected with L. chagasi and strongly suggest that microglia and astrocytes are involved in the pathogenesis of the neurological disorders of visceral leishmaniasis in dogs.

Immunodiagnosis in cerebrospinal fluid of cerebral toxoplasmosis and HIV-infected patients using Toxoplasma gondii excreted/secreted antigens.

Cerebral toxoplasmosis is the most common neurologic opportunistic infection in HIV-infected patients. Excretory-secretory antigens (ESA) are the majority of the circulating antigens in sera from hosts with acute toxoplasmosis, and their usefulness as antigens has been shown. This study considered whether it could find anti-ESA antibodies in cerebrospinal fluid (CSF) and whether these antibodies can be markers of active infection. Samples of CSF from 270 HIV-infected patients were analyzed and divided into 3 groups according to the presence or absence of active toxoplasmosis. Group I: 99 patients with cerebral toxoplasmosis; group II: 112 patients with other opportunistic neurologic diseases and seropositive for toxoplasmosis; and group III: 59 patients with other opportunistic neurologic diseases and seronegative for toxoplasmosis. Toxoplasma gondii ESA and a crude tachyzoite antigen were used as antigens using ELISA and immunoblotting. The statistical analysis was done using the F test and unpaired Student's t test. Crude tachyzoite antigen: mean ELISA-relative values ± standard error for CSF of groups I and II were 7.0 ± 0.27 and 3.9 ± 0.19, respectively. Variance analysis revealed that results of both groups of patients were statistically different (1.80, P = 0.0025). The difference between the mean results was 3.0 ± 0.3, and the Student's t test value was 9.41 (P = 0.0001). Samples from groups I and II were reactive by immunoblotting, with similar intensities. In ESA-ELISA, the mean for group I was 9.0 ± 0.39. Group II showed a mean value of 2.7 ± 0.12. Both groups were statistically different (9.16, P < 0.001). However, in ESA, the difference between the mean results was higher (6.2 ± 0.39) and the Student's t test value was 16.04 (P < 0.0001). Similar results were shown in immunoblotting where a CSF sample from group I reacted well with ESA, and the sample from a group II patient failed to do so. The mean ELISA-relative value of the control group (group III) was 0.5 ± 0.09 for the first antigen and 0.4 ± 0.22 for the second. ESA-ELISA and/or immunoblotting of CSF samples can be used for diagnosis of cerebral toxoplasmosis in association with clinical, serologic, and radiological information, thus providing a simple straightforward methodology, particularly suitable in countries with high prevalence of latent toxoplasmosis in the general population.

Antibody coefficients for the diagnosis of equine protozoal myeloencephalitis.

BACKGROUND: Diagnosis of equine protozoal myeloencephalitis (EPM) remains a challenge for equine practitioners. Current utilized methods have inadequate sensitivity and specificity, because of a high number of false positive results. HYPOTHESIS/OBJECTIVE: Evaluation of antibody indices to Sarcocystis neurona should provide high sensitivity and specificity for diagnosis of EPM. ANIMALS: Archived samples from 29 clinical patients. METHODS: Archived serum and cerebrospinal fluid (CSF) samples from clinical patients with either EPM (14) or cervical vertebral compressive myelopathy (CVM) (15) were examined and tested for anti-S. neurona antibodies by the SnSAG2 ELISA. The results were used to calculate the antibody index (AI) and C-value. Sensitivity and specificity were calculated, and the AI, C-value, immunoglobulin G (IgG) concentrations, and anti-S. neurona titers compared. In addition, negative CSF was spiked in varying concentrations with blood from a horse with a high anti-S. neurona titer, and the tests repeated. RESULTS: Results demonstrated that the IgG concentration, anti-S. neurona titer, AI, and C-value were significantly higher (P < .05) in horses with EPM than in those with CVM. Sensitivity and specificity of the AI was 71 and 100%, respectively, and that of the C-value was 86 and 100%, respectively. In addition, the AI and C-value from the samples spiked with S. neurona positive blood remained below 1 (eg, negative) in CSF with a red blood cell (RBC) count up to 10(5) RBC/µL. CONCLUSIONS/CLINICAL IMPORTANCE: Results of the study demonstrate the value of calculating the AI and C-value in the diagnosis of EPM in horses. In addition, the test is robust in the presence of blood contamination.