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Parasite infections affect billions of people and their domesticated animals worldwide, and remain as a significant cause of morbidity and mortality, but such diseases are still neglected in endemic countries. Therapeutic interventions consisted mostly of drugs, which are highly toxic and may lead to resistance. The immunopathology of parasites is very complex due to their multistage life cycles and long lifetime involving several hosts, leading many times to chronic infections and sometimes to death, by compromising nutritional status, affecting cognitive processes, and inducing severe tissue reactions. Vaccination is a challenge, and immunotherapy is completely disregarded because of their complex interactions with hosts and vectors. This review will bring concepts of immunological aspects for some important parasitic infections, and present the most recent phage display-derived antibodies or peptidomimetics for parasite targets. This chapter will also discuss the future perspectives of such potential anti-infective immunobiologicals for parasitic diseases.

To determine what role, if any, toxoplasmosis plays in the mental retardation of children, sera from 345 mentally retarded children were tested for the presence of antibodies to Toxoplasma gondii. The serological tests employed were the complement-fixation, the Sabin-Feldman dye test and the immunofluorescence test. The donors were also skin-tested with toxoplasmin.Of 345 mentally retarded donors nine gave a positive skin reaction, 15 possessed complement-fixing antibodies, 21 had immunofluorescent antibodies and 45 had dye test antibodies to T. gondii.The incidence of antibodies to T. gondii in the mentally retarded group was approximately the same as in the normal control group of the same age, and less than in the group suspected of having toxoplasmosis. It is concluded that in the children in this study toxoplasmosis played little or no role as a predisposing factor in the occurrence of congenital mental deficiency.

A new serologic test for antibodies to Toxoplasma is described, which is based upon inhibition of specific staining with fluorescent antibody. In performing the test, a mixture of the test serum and known fluorescein-labelled antiserum is added to a dried smear of toxoplasms for 1 hour at 37 degrees C. The smear is then rinsed and examined with a fluorescence microscope. Reduction in the brightness of fluorescence, as compared to that of a negative control slide, indicates the presence of antibody in the test serum. A comparison of the results of this test with those of the methylene blue dye test showed a strong parallelism between the two sets of results. On the other hand, the complement-fixation test for toxoplasmosis did not yield nearly as many positives as the inhibition test. The specificity of the new test was studied by comparing it with dye test results and clinical histories in human patients, and by testing a group of animals immunized with a variety of non-Toxoplasma antigens. No evidence of cross-reactions was obtained in the latter series. Some advantages and disadvantages of the inhibition test are discussed.

Infections of Eimeria stiedae in normal and splenectomized rabbits and of Leishmania enriettii in normal rabbits and guinea-pigs and in splenectomized rabbits did not produce dye test antibodies. Guinea-pigs injected with Atoxoplasma sp. and rabbits immunized with cultures of Crithidia fasciculata were found to be negative for dye test antibodies. Mice which had been infected with Trypanosoma cruzi did not show dye test antibodies. All these animals, except one guinea-pig infected with Leishmania enriettii, were negative in the complement-fixation test for toxoplasmosis using the egg antigen. These findings are discussed in the light of previous reports.

There is a need to reconsider the acceptance of organs from donors considered suboptimal, in the absence of data. Toxoplasma antibody-positive donors (TPD) constitute one such group. The objective of our study was to compare graft survival in deceased donor renal transplant (Tx) recipients, stratified by Toxoplasma IgG status, using the Organ Procurement and Transplantation Network (OPTN) database. A log-linear event history regression model for graft failure categorized by Toxoplasma IgG status, adjusting for confounders was applied to first kidney-only Tx recipients from 2018 to 2022. Of the 51,422 Tx, 4,317 (8.4%) were from TPD. Acute rejection and graft failure (5% each) were similar between groups. Crude graft failure was 7.3 failures per 100 person-years for TPD recipients compared to 6.5 failures per 100 person-years for the Toxoplasma-negative group (p 0.008). The crude failure rate ratio was 1.14 with an adjusted hazard rate ratio of 1.04 (95% CI: 0.94, 1.15, p 0.39). In renal Tx recipients, TPD graft recipients have comparable survival to Tx from Toxoplasma-negative recipients. While caution and close monitoring of recipients post-Tx for surveillance of disseminated toxoplasmosis are still warranted, our study suggests that patients can be successfully managed using TPD organs.

This study presents an evaluation of seventeen newly produced recombinant trivalent chimeric proteins (containing the same immunodominant fragment of SAG1 and SAG2 of Toxoplasma gondii antigens, and an additional immunodominant fragment of one of the parasite antigens, such as AMA1, GRA1, GRA2, GRA5, GRA6, GRA7, GRA9, LDH2, MAG1, MIC1, MIC3, P35, and ROP1) as a potential alternative to the whole-cell tachyzoite lysate (TLA) used in the detection of infection in small ruminants. These recombinant proteins, obtained by genetic engineering and molecular biology methods, were tested for their reactivity with specific anti-Toxoplasma IgG antibodies contained in serum samples of small ruminants (192 samples of sheep serum and 95 samples of goat serum) using an enzyme-linked immunosorbent assay (ELISA). The reactivity of six recombinant trivalent chimeric proteins (SAG1-SAG2-GRA5, SAG1-SAG2-GRA9, SAG1-SAG2-MIC1, SAG1-SAG2-MIC3, SAG1-SAG2-P35, and SAG1-SAG2-ROP1) with IgG antibodies generated during T. gondii invasion was comparable to the sensitivity of TLA-based IgG ELISA (100%). The obtained results show a strong correlation with the results obtained for TLA. This suggests that these protein preparations may be a potential alternative to TLA used in commercial tests and could be used to develop a cheaper test for the detection of parasite infection in small ruminants. [ABSTRACT FROM AUTHOR]

Toxoplasmosis affects various organisms, including humans. In 2018, the largest outbreak of human toxoplasmosis described so far was reported in southern Brazil, with 809 human cases reported, and water as the potentially primary source of infection. Therefore, in this study, we aimed to evaluate the seroprevalence of Toxoplasma gondii in naturally infected domestic cats before and after the human toxoplasmosis outbreak, as well as the potential for environmental contamination by the number of cats infected after the outbreak. We evaluated 381 serum samples from domestic cats in southern Brazil, using an indirect immunofluorescence assay, with samples considered positive at a titer of 1:20. We found that 73% (204/279) and 27% (75/279) of the samples analyzed before the outbreak were negative and positive, respectively. After the outbreak, 62% (69/112) were negative of the samples were and 38% (43/112) were positive. Notably, the proportion of positive samples before the outbreak before (27%) was significantly lower than that after the outbreak (38%; P = 0.020). Therefore, the increased seroprevalence of T. gondii in cats was probably correlated with the ingestion of contaminated water. Therefore, it is important to monitor animals, mainly definitive hosts, after toxoplasmosis outbreaks, considering that these animals can contaminate the environment and, consequently, humans. [ABSTRACT FROM AUTHOR]

Toxoplasma gondii is an important zoonotic parasite worldwide, but it has received limited attention in Ukraine. A seroepidemiological study was conducted and samples from 452 wild boars that had been hunted in 2006–2011 in 23 of the 25 regions of Ukraine were tested to estimate T. gondii seroprevalence. A locally available commercial enzyme-linked immunosorbent assay (ELISA) was used for the investigation. Additionally, we tested 92 of the sera using a widely used commercial multi-species ELISA and an indirect immunofluorescence antibody test (IFAT). With the locally available ELISA, 35 of the 452 wild boars tested positive, yielding a seroprevalence estimate of 7.7% (95% confidence interval 5.5–10.5). The seropositive wild boars originated from eight of the regions. Using the majority criteria, 10/92 samples tested using both ELISAs and the IFAT were considered positive, yielding an estimated seroprevalence of 10.9% within the subset of samples. The highest seroprevalence was observed in wild boars hunted in Luhans'k (30.0%), Odesa (17.7%) and Kharkiv (12.7%). Seroprevalence was higher in older animals (13.3% for age group >12 months and 7.7% for age group ≤12 months). This is the first seroepidemiological study of T. gondii in wild boars in Ukraine. Assuming that seropositivity indicates presence of infectious parasites in the tissues, eating undercooked meat of wild boars hunted in Ukraine could be a potential source of infection to other hosts, including humans.

BackgroundClinically useful predictors for fatal toxoplasmosis are lacking. We investigated the value of serological assays for antibodies to whole Toxoplasma antigens and to peptide antigens of the Toxoplasma cyst matrix antigen 1 (MAG1), for predicting incident toxoplasmic encephalitis (TE) in people living with human immunodeficiency virus (HIV; PLWH).MethodsWe performed a nested case control study, conducted within the Multicenter AIDS Cohort Study (MACS), using serum samples obtained 2 years prior to diagnosis of TE from 28 cases, and 37 HIV disease-matched Toxoplasma seropositive controls at matched time-points. Sera were tested for Toxoplasma antibodies using a commercial assay and for antibodies to MAG1_4.2 and MAG1_5.2 peptides in enzyme-linked immunosorbent assay (ELISA).ResultsTwo years prior to clinical diagnosis, 68% of TE cases were MAG1_4.2 seropositive compared with 16% of controls (odds ratio [OR] 25.0, 95% confidence interval [CI] 3.14-199.18). Corresponding results for MAG1_5.2 seropositivity were 36% and 14% (OR 3.6, 95% CI .95-13.42). Higher levels of antibody to MAG1_4.2 (OR 18.5 per doubling of the optical density [OD] value, 95% CI 1.41-242) and to Toxoplasma (OR 2.91 for each OD unit increase, 95% CI 1.48-5.72) were also associated with the risk of TE. When seropositivity was defined as the presence of MAG1 antibody or relatively high levels of Toxoplasma antibody, the sensitivity was 89% and specificity was 68% for subsequent TE.ConclusionsAntibodies to MAG1 showed predictive value on the occurrence of TE in PLWH, and the predictive performance was further improved by adding the levels of Toxoplasma antibody. These measures could be clinically useful for predicting subsequent diseases in multiple at-risk populations.

This study presents an evaluation of seventeen newly produced recombinant trivalent chimeric proteins (containing the same immunodominant fragment of SAG1 and SAG2 of Toxoplasma gondii antigens, and an additional immunodominant fragment of one of the parasite antigens, such as AMA1, GRA1, GRA2, GRA5, GRA6, GRA7, GRA9, LDH2, MAG1, MIC1, MIC3, P35, and ROP1) as a potential alternative to the whole-cell tachyzoite lysate (TLA) used in the detection of infection in small ruminants. These recombinant proteins, obtained by genetic engineering and molecular biology methods, were tested for their reactivity with specific anti-Toxoplasma IgG antibodies contained in serum samples of small ruminants (192 samples of sheep serum and 95 samples of goat serum) using an enzyme-linked immunosorbent assay (ELISA). The reactivity of six recombinant trivalent chimeric proteins (SAG1-SAG2-GRA5, SAG1-SAG2-GRA9, SAG1-SAG2-MIC1, SAG1-SAG2-MIC3, SAG1-SAG2-P35, and SAG1-SAG2-ROP1) with IgG antibodies generated during T. gondii invasion was comparable to the sensitivity of TLA-based IgG ELISA (100%). The obtained results show a strong correlation with the results obtained for TLA. This suggests that these protein preparations may be a potential alternative to TLA used in commercial tests and could be used to develop a cheaper test for the detection of parasite infection in small ruminants.

SARS-CoV-2 is the causal agent of COVID-19; the first report of SARS-CoV-2 infection was in December 2019 in Wuhan, China. This virus has since caused the largest pandemic in history, and the number of deaths and infections has been significant. Nevertheless, the development of vaccines has helped to reduce both deaths and infections. Comorbidities such as diabetes, hypertension, heart and lung diseases, and obesity have been identified as additional risk factors for infection and the progression of COVID-19. Additionally, latent toxoplasmosis has been reported to be a risk factor for acquiring COVID-19 in some studies, but other studies have suggested a negative association between these two infections. Furthermore, in patients after vaccination or with COVID-19 and coinfection, an increase in the lethality and mortality of toxoplasmosis has been observed. Therefore, the objective of the current study is to determine the association of toxoplasmosis with COVID-19 in patients diagnosed with COVID-19. Serum samples from 384 patients previously diagnosed with COVID-19 using IgG antibodies against the S1/S2 antigens of SARS-CoV-2 were collected. Subsequently, anti-Toxoplasma IgG and IgM antibodies were analyzed with ELISA. Statistical analysis was performed using SPSS Version 20.0 frequencies, percentages, 2 × 2 tables, and the Pearson correlation coefficient. IgG and IgM anti-Toxoplasma antibodies were positive in 105/384 (27.34%) and (26/191) 13.6% of patients, respectively. The positivity for both infections was higher in patients aged >40 years old. Subjects who were overweight or obese were mainly positive for both IgG antibodies against S1/S2 SARS-CoV-2 and Toxoplasma antibodies. In conclusion, the coinfection rate was 21.7%. The prevalence of S1/S2 SARS-CoV-2 was 308/384 (80.2%), and the percentage of Toxoplasma antibodies was 27.34%. [ABSTRACT FROM AUTHOR]

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Control of CNS pathogens by CD8 T cells is key to avoid fatal neuroinflammation. Yet, the modalities of MHC I presentation in the brain are poorly understood. Here, we analyze the antigen presentation mechanisms underlying CD8 T cell-mediated control of the Toxoplasma gondii parasite in the CNS. We show that MHC I presentation of an efficiently processed model antigen (GRA6-OVA), even when not expressed in the bradyzoite stage, reduces cyst burden and dampens encephalitis in C57BL/6 mice. Antigen presentation assays with infected primary neurons reveal a correlation between lower MHC I presentation of tachyzoite antigens by neurons and poor parasite control in vivo. Using conditional MHC I-deficient mice, we find that neuronal MHC I presentation is required for robust restriction of T. gondii in the CNS during chronic phase, showing the importance of MHC I presentation by CNS neurons in the control of a prevalent brain pathogen.

Exposure to neurotropic pathogens has been hypothesized to be a risk factor for the development of bipolar disorder (BD). However, evidence so far is inconsistent. We, therefore, analyzed the seroprevalence and titer levels of IgG antibodies against several herpesviruses and Toxoplasma gondii (T. gondii) in plasma of 760 patients with a bipolar disorder, 144 first-degree matched relatives and 132 controls of the Dutch Bipolar (DB) Cohort using ELISA. In addition, we performed a literature-based meta-analysis on the seroprevalence of IgG antibodies against these pathogens (n = 14). Our results in the DB Cohort and subsequent meta-analysis (n = 2364 BD patients, n = 5101 controls) show no association between exposure to herpesviruses and bipolar disorder (HSV-1 [adjusted OR 0.842, 95% CI 0.567-1.230], HSV-2 [adjusted OR 0.877, 95% CI 0.437-1.761], CMV [adjusted OR 0.884 95% CI 0.603-1.295], EBV [adjusted OR 0.968 95% CI 0.658-1.423]). In the DB Cohort, we did not find an association between bipolar disorder and T. gondii titer or seroprevalence either [adjusted OR 1.018, 95% CI 0.672-1.542]. The overall OR was not significant for T. gondii [OR: 1.4, 95% CI 0.95-1.90, p = 0.09), but subgroup analyses in age groups below 40 years showed a significantly increased seroprevalence of T. gondii IgGs in BD [OR: 1.8 (95% CI 1.10-2.89, p = 0.021]. Our meta-analysis indicates that T. gondii exposure may be a risk factor for BD in certain subpopulations.

Toxoplasma gondii is a ubiquitous zoonotic parasite, with felines being the only definitive hosts. Cats shed oocysts with their faeces, and seroprevalence studies can be used to indirectly assess the environmental contamination. The current study aimed to evaluate T. gondii seroprevalence in Greek cats and identify possible risk factors. In total, 1554 blood samples were analyzed from different cats across all nine geographic regions of Greece, and a short questionnaire was completed for each cat. A rapid immunochromatographic test was used to detect anti-T. gondii antibodies, IgG type, and 21.8% of cats were seropositive. Regarding risk factors, when chi-square tests were applied, seropositivity was significantly higher (p < 0.05) in rural cats, cats with outdoor access, and hunting cats. Gender, age, ownership, and raw feeding were not significant risk factors, although female, adult, stray, and raw-feeding cats had a higher seroprevalence than their counterparts. Binary logistic regression models were developed to adjust for the confounding effects of the initially recognized risk factors, and only hunting in urban areas remained a significant risk factor. Greek cats had lower seropositivity than the average European value, and the present research highlights the importance of updated seroprevalence and risk factor studies within the context of One-Health. [ABSTRACT FROM AUTHOR]

BACKGROUND: Toxoplasma gondii is an obligate intracellular protozoan parasite that causes congenital toxoplasmosis, as well as other serious clinical presentations in immune compromised humans. The parasite has also been recently linked to behavioral diseases in humans and other mammalian hosts. New antigens are being evaluated to develop a diagnostic kit for the diagnosis of acute infection or a protective vaccine. METHODS: In this study, we have focused on the discovery of new antigenic proteins from T. gondii genomic data using a high throughput protein microarray screening. To date, microarrays containing > 2870 candidate exon products of T. gondii have been probed with sera collected from patients with toxoplasmosis. Here, the protein microarrays are probed with well-characterized serum samples from animal models administered orally with oocysts or tissue cysts. The aim was to discover the antigens that overlap in the mouse profile with human antibody profiles published previously. For this, a reactive antigen list of 240 antigens recognized by murine IgG and IgM was identified using pooled sera from orally infected mice. RESULTS: Analyses of screening data have identified plenty of antigens and showed strong immunogenicity in both mouse and human antibody profiles. Among them, ROP1, GRA2, GRA3, GRA4, GRA5, GRA6, GRA7, GRA8, GRA14, MIC1, MIC2 and MAG1 have shown strong immunogenicity and used as antigen in development of vaccines or serological diagnostic assays in previous studies. CONCLUSION: In addition to the above findings, ROP6, MIC12, SRS29A and SRS13 have shown strong immunogenicity but have not been tested in development of a diagnostic assay or a vaccine model yet.

Abortion imposes great economical loss in productivity and by product of small ruminants. The present study was conducted to determine the rate of abortion and apparent prevalence of Brucellosis, Toxoplasmosis and Q-fever in aborted goats from June 2015 to August 2019 in North Shoa, Ethiopia. During consecutive years of clinical case study 503 does were entered to mating, of which100 (19.5 %) animals aborted. There were significant differences (p=0.013) in abortion among parities. A total of 35 serum samples were collected from aborted does within six months periods. All samples were screened initially with Rose Bengal plate test (RBPT) for Brucellosis. All RBPT positive were further tested by i-ELISA. Also, serums were tasted to screen specific antibody against Q-fever and Toxoplasmosis using i-ELISA. Of total tested 64.7 % and 8.6 % of them were positive for Q-fever and Toxoplasmosis, respectively, but neither of them was positive for Brucellosis. The present clinical study revealed that abortion was the cause of kids' loss and serological investigation of antibody against Q-fever and Toxoplasmosis showed that the agents were the major causes of abortion. Even though there was no positive reactor does to brucellosis, the result must be interpreted with care since absence of evidence is not evidence of absence. Beside of this, some samples collected from active cases were sero-negative for neither of tested antibodies; it indicated there was other cause/s of abortion in the study site. These interesting findings deserve further detail study by using more sensitive diagnostic test in order to examine the full extent of the problem in small ruminant populations. Also, an awareness-raising campaign should be launched to educate farm workers and professionals about proper preventive and control measures for such zoonotic diseases. [ABSTRACT FROM AUTHOR]

SARS-CoV-2 is the causal agent of COVID-19; the first report of SARS-CoV-2 infection was in December 2019 in Wuhan, China. This virus has since caused the largest pandemic in history, and the number of deaths and infections has been significant. Nevertheless, the development of vaccines has helped to reduce both deaths and infections. Comorbidities such as diabetes, hypertension, heart and lung diseases, and obesity have been identified as additional risk factors for infection and the progression of COVID-19. Additionally, latent toxoplasmosis has been reported to be a risk factor for acquiring COVID-19 in some studies, but other studies have suggested a negative association between these two infections. Furthermore, in patients after vaccination or with COVID-19 and coinfection, an increase in the lethality and mortality of toxoplasmosis has been observed. Therefore, the objective of the current study is to determine the association of toxoplasmosis with COVID-19 in patients diagnosed with COVID-19. Serum samples from 384 patients previously diagnosed with COVID-19 using IgG antibodies against the S1/S2 antigens of SARS-CoV-2 were collected. Subsequently, anti-Toxoplasma IgG and IgM antibodies were analyzed with ELISA. Statistical analysis was performed using SPSS Version 20.0 frequencies, percentages, 2 × 2 tables, and the Pearson correlation coefficient. IgG and IgM anti-Toxoplasma antibodies were positive in 105/384 (27.34%) and (26/191) 13.6% of patients, respectively. The positivity for both infections was higher in patients aged >40 years old. Subjects who were overweight or obese were mainly positive for both IgG antibodies against S1/S2 SARS-CoV-2 and Toxoplasma antibodies. In conclusion, the coinfection rate was 21.7%. The prevalence of S1/S2 SARS-CoV-2 was 308/384 (80.2%), and the percentage of Toxoplasma antibodies was 27.34%.

Epidemiological studies on infections by Toxoplasma gondii and Neospora caninum in cats in the North Region of Brazil are scarce. We intended to assess the seroprevalence in cats of anti-T. gondii and anti-N. caninum antibodies, as well as the associated risk factors that may lead them to contract these infections in Rolim de Moura, state of Rondônia, North Brazil. For this, blood serum samples of 100 cats from different regions of the city were evaluated. To assess possible factors associated with infections, epidemiological questionnaires were applied to tutors. The Immunofluorescence Antibody Test (IFAT) was performed for anti-T. gondii (cutoff 1:16) and anti-N. caninum (cutoff 1:50) antibodies. After identifying the positive samples, antibody titration was performed. The results showed the prevalence of 26% (26/100) of anti-T. gondii antibodies, with titration varying between 1:16 to 1:8192. There were no factors associated with the prevalence of anti-T. gondii antibodies in the multivariate analysis in this study. There was no occurrence of seropositive cats for anti-N. caninum. It was concluded that there was a high prevalence of anti-T. gondii antibodies in cats in Rolim de Moura, state of Rondônia, North Brazil. However, the evaluated animals did not present anti-N. caninum antibodies. Therefore, knowing that T. gondii has different transmission forms, we emphasize the importance of spreading more information to the population about cat’s relevance in the T. gondii life cycle and how to avoid the parasite transmission and proliferation.

Toxoplasmosis is a worldwide zoonotic disease with different and complex routes for transmission. Workers occupationally exposed to animals or raw meat and viscera (WOE) may be at more risk than the general population, however conflicting data exist on the risk of developing toxoplasmosis due to this close contact. To add knowledge to this topic, the aim of the present study was to ascertain if WOE were more likely to be anti-T. gondii IgG seropositive than the general population as well as to study risk factors for T. gondii infection such as professional activity, gender, age, years of work and region. For this purpose, a case–control study using archived samples was setup. A total of 114 WOE (including pig slaughterhouse workers, butchers, veterinarians and farmers) and 228 anonymous volunteers (matched with cases by region, age and gender) were studied for anti-T. gondii IgG. A significantly higher anti-T. gondii IgG occurrence (p = 0.0282) was found in WOE when compared with the general population (72.8% [CI = 64.6–81.0%] versus 60.1% [CI = 54.6–65.6%]). Multivariate analysis showed that WOE of more than 50 years of age were more likely to be seropositive for anti-T. gondii IgG (aOR = 16.8; 95% CI 3.6–77.5; p < 0.001) than those aged less than 50 years. To our knowledge, this is the first case–control study on the prevalence of anti-T. gondii IgG in WOE in Portugal, also showing an added risk for T. gondii infection in those exposed to animals or their meat and viscera. [ABSTRACT FROM AUTHOR]

Copyright of Diyala Journal of Medicine is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background Human immunodeficiency virus (HIV)-associated neurocognitive disorders persist despite suppressive antiretroviral therapy (ART). Because latent Toxoplasma infection (LTI) may adversely impact brain function, we investigated its impact on neurocognitive impairment (NCI) in people living with HIV disease.Methods Two hundred sixty-three HIV-infected adults underwent comprehensive neurocognitive assessments and had anti-Toxoplasma gondii immunoglobulin G (anti-Toxo IgG) measured by qualitative and quantitative enzyme-linked immunosorbent assays.Results Participants were mostly middle-aged white men who were taking ART (70%). LTI was detected in 30 (11.4%) participants and was associated with a significantly greater prevalence of global NCI (LTI positive [LTI+] = 57% and LTI negative [LTI-] = 34%) (odds ratio, 1.67; 95% confidence interval, 1.17-2.40; P = .017). Deficits were more prevalent in the LTI+ vs the LTI- group in 6 of 7 cognitive domains with statistical significance reached for delayed recall (P < .01). The probability of NCI increased with higher CD4+ T-cell counts among LTI+ individuals but with lower CD4+ T-cell counts in LTI- persons. A strong correlation (r = .93) between anti-Toxo IgG levels and global deficit score was found in a subgroup of 9 patients. Biomarkers indicative of central nervous system inflammation did not differ between LTI+ and LTI- participants.Conclusions In this cross-sectional analysis, LTI was associated with NCI, especially in those with higher CD4+ T-cell counts. Longitudinal studies to investigate the role of neuroinflammation and neuronal injury in LTI patients with NCI and trials of anti-Toxoplasma therapy should be pursued.