HIV Y TOXOPLASMOSIS CEREBRAL A PROPÓSITO DE UN CASO

Introducción: En Ecuador al igual que en el resto del mundo la infección por virus de inmunodeficiencia humana (VIH) constituye un problema de salud pública, con diagnósticos tardíos en fase avanzada del síndrome de inmunodeficiencia adquirida (SIDA), con toxoplasmosis cerebral una de las infecciones oportunistas más frecuentes que ocurre en pacientes con linfocitos CD4<200/µL. Objetivo: realizar diagnóstico precoz de toxoplasmosis cerebral en pacientes con SIDA y considerar como una verdadera emergencia a fin de disminuir la mortalidad de los pacientes inmunosuprimidos. Caso clínico: paciente de género masculino de 31 años, con antecedente de infección por HIV diagnosticado hace 19 días, con convulsiones tónico-clónicas generalizadas de tres meses de evolución, cefalea holocraneana de moderada intensidad, parestesias en hemicara derecha, asimetría comisura labial, tres días antes de su ingreso las crisis convulsivas se hacen diarias, repetitivas y se acompañan de fiebre, al examen físico disartria leve y monoparesia del miembro superior derecho, con biometría hemática con leucocitos 5270 mm3, IgG positiva anti-Toxoplasma gondii, linfocitosis discreta, pruebas de cuarta y tercera generación para HIV positivas, CD4 de 74/mm3, carga viral de 61500 copias/ml, resonancia magnética nuclear cerebral contrastada con lesiones intra-axilares corticales, con área hipointensa central, a nivel del lóbulo parietal izquierdo y occipital bilateral, se establece el diagnóstico de encefalitis toxoplásmica, indicándose tratamiento con trimetropin/cotrimoxazol, dexametosona y fármacos antirretrovirales con abacavir-lamivudina y lopinavir-ritonavir teniendo una buena evolución clínica. Conclusiones: El diagnóstico precoz de encefalitis toxoplásmica basado en criterios epidemiológicos, clínicos, de laboratorio y a la resonancia magnética, permitió buena respuesta al tratamiento empírico antitoxoplásmico. Palabras claves: Toxoplasmosis, infecciones oportunistas, encefalitis ABSTRACT Introduction: In Ecuador, as in the rest of the world, human immunodeficiency virus (HIV) infection constitutes a public health problem, with late diagnoses in an advanced phase of acquired immunodeficiency syndrome (AIDS), with cerebral toxoplasmosis one of the more frequent opportunistic infections that occur in patients with CD4 lymphocytes <100 / µL. Objective: to make an early diagnosis of cerebral toxoplasmosis in patients with AIDS and to consider it as a true emergency in order to reduce the mortality of immunosuppressed patients. Clinical case: a 31-year-old male patient, with generalized tonic-clonic seizures of three months of evolution, moderate intensity holocranial headache, paresthesia in the right side of the face, asymmetry of the labial commissure, three days before admission the seizures become daily, frequent and accompanied by fever, on physical examination mild dysarthria and monoparesis of the right upper limb, with hematic biometry with leukocytes 5270 mm3, discrete lymphocytosis, fourth and third generation tests for HIV positive, CD4 of 74 / mm3, viral load of 61,500 copies / ml, brain nuclear magnetic resonance with cortical intra-axillary lesions, with a central hypointense area, at the level of the left parietal lobe and bilateral occipital, the diagnosis of toxoplasmic encephalitis is established, indicating treatment with trimethropin / cotrimoxazole, dexamethasone and antiretroviral drugs with abacavir-lamivudine and lopinavir-ritonavir having a good clinical evolution. Conclusions: The early diagnosis of toxoplasmic encephalitis based on epidemiological, clinical, laboratory and magnetic resonance criteria, allowed a good response to empirical antitoxoplasmic treatment. Keywords: Toxoplasmosis, opportunistic infections, encephalitis

Geospatial Distribution of Toxoplasmosis Prevalence among Livestock, Pets and Humans in China, 1984-2020

Background: Toxoplasma gondii (T. gondii) is an important foodborne zoonotic parasite with respect to abortion, intracranial calcifications, congenital hydrocephalus, retinochoroiditis, and toxoplasmic encephalitis in severely immunosuppressed individuals. Undercooked/raw meat containing cyst-stage bradyzoites and contaminated pets are presumed to constitute a major source of human infection. Although many seroprevalence studies have been performed in humans and different animal species in China, data on the geospatial distribution of toxoplasmosis prevalence are extremely scarce. The aim of the present study was to investigate the prevalence and geospatial distribution of toxoplasmosis among livestock, pets and humans in China using geographic information system (GIS) for the prevention and control of toxoplasmosis.Methods: This article is based on the data from PubMed, China National Knowledge Infrastructure (CNKI) and Baidu Scholar databases from 1984 up to 2020 regarding prevalence data of toxoplasmosis among livestock (sheep and goats, swines, cattle and yaks), pets (cats, dogs) and humans in China. Geospatial distribution of the prevalence of toxoplasmosis in these hosts was performed using the GIS visualization techniques.Results: Analysis revealed wide geospatial variation of toxoplasmosis in China. The estimated pooled seroprevalence of T. gondii was ranged from 3.98% to 43.02% among sheep and goats in China, 0.75% to 30.34% in cattle and yaks, 10.45% to 66.47% in swines, 2.50% to 60.00% in cats, 0.56% to 27.65% in dogs, and 0.72% to 23.41% in humans. The higher seroprevalences of T. gondii were observed in districts Chongqing, Zhejiang and Beijing in sheep and goats. The infection rates of T. gondii in cattle and yaks were higher in districts Guizhou, Zhejiang and Chongqing. Moreover, the swines from districts Chongqing and Guizhou were also most severely infected with T. gondii. In cats, districts Shanxi, Hebei and Yunnan had higher seroprevalences of T. gondii and, the infections among dogs were higher in districts Yunnan and Hebei as well. Furthermore, higher infection pressure of T. gondii exists in districts Taiwan and Tibet in humans.Conclusion: The present study indicated that the infection with T. gondii was widely spread in China, with a wide range of variation. The investigation of T. gondii infection in livestock, pets and humans can be useful for assessing T. gondii environmental contamination and the risk for public health. Certain measures can be taken to prevent the prevalence of T. gondii infection in China, such as strengthening the management of livestock farms, keeping the barn clean, preventing feline excreta from polluting environment, using filtered water or water boiling, wearing gloves when handling raw meat and improving the practice of good hand hygiene.

A Family of Toxoplasma gondii Genes Related to GRA12 Regulate Cyst Burdens and Cyst Reactivation

ABSTRACT Toxoplasma gondii causes a chronic infection that renders the immunocompromised human host susceptible to toxoplasmic encephalitis triggered by cyst reactivation in the central nervous system. The dense granule protein GRA12 is a major parasite virulence factor required for parasite survival during acute infection. Here, we characterized the role of four GRA12-related genes in acute and chronic stages of infection. While GRA12A, GRA12B, and GRA12D were highly expressed in asexual stage tachyzoites and bradyzoites, expression of GRA12C appeared to be restricted to the sexual stages. In contrast to deletion of GRA12 (Δgra12), no major defects in acute virulence were observed in Δgra12A, Δgra12B, or Δgra12D parasites, though Δgra12B parasites exhibited an increased tachyzoite replication rate. Bradyzoites secreted GRA12A, GRA12B, and GRA12D and incorporated these molecules into the developing cyst wall, as well as the cyst matrix in distinct patterns. Similar to GRA12, GRA12A, GRA12B, and GRA12D colocalized with the dense granules in extracellular tachyzoites, with GRA2 and the intravacuolar network in the tachyzoite stage parasitophorous vacuole and with GRA2 in the cyst matrix and cyst wall. Chronic stage cyst burdens were decreased in mice infected with Δgra12A parasites and were increased in mice infected with Δgra12B parasites. However, Δgra12B cysts were not efficiently maintained in vivo. Δgra12A, Δgra12B, and Δgra12D in vitro cysts displayed a reduced reactivation efficiency, and reactivation of Δgra12A cysts was delayed. Collectively, our results suggest that a family of genes related to GRA12 play significant roles in the formation, maintenance, and reactivation of chronic stage cysts. IMPORTANCE If host immunity weakens, Toxoplasma gondii cysts recrudesce in the central nervous system and cause a severe toxoplasmic encephalitis. Current therapies target acute stage infection but do not eliminate chronic cysts. Parasite molecules that mediate the development and persistence of chronic infection are poorly characterized. Dense granule (GRA) proteins such as GRA12 are key virulence factors during acute infection. Here, we investigated four GRA12-related genes. GRA12-related genes were not major virulence factors during acute infection. Instead, GRA12-related proteins localized at the cyst wall and cyst matrix and played significant roles in cyst development, persistence, and reactivation during chronic infection. Similar to GRA12, the GRA12-related proteins selectively associated with the intravacuolar network of membranes inside the vacuole. Collectively, our results support the hypothesis that GRA12 proteins associated with the intravacuolar membrane system support parasite virulence during acute infection and cyst development, persistence, and reactivation during chronic infection.

Seroprevalence Toxoplasma Infection among HIV/AIDS Patients in Kathmandu, Nepal

Toxoplasmosis is a zoonotic disease caused by Toxoplasma gondii affecting about one third of the world’s population. It can be asymptomatic to fatal toxoplasmic encephalitis depending on the immune status of infected individuals. Among HIV/AIDS patients, it usually manifest as life-threatening condition. We, therefore, studied the seroprevalence of T. gondii infection among HIV/AIDS patients in Nepal and this report constitutes the first report from Nepal. A total of 45 HIV/AIDS patients were included in this study. The serum samples collected and stored at -20°C were tested for Toxoplasma IgG and IgM antibodies at National Public Health Laboratory, Teku, Kathmandu using Snibe Maglumi 1000 Fully Automated Immunoassay Analyzer and the results were expressed in AU/ml. The blood put into the EDTA tube was used for CD4 count using BD FACS Calibur Flow Cytometer. In this study, 33.3% (15/45) HIV infected patients were seropositive for anti-T. gondii IgG. However, none of them were positive to anti- T. gondii IgM. Most of the patients (36 out of 45 patients) had <200/mm3 CD4 cell count. However, out of them 36.1% (13/36) were seropositive to anti-T. gondii IgG whereas 22.2% (2/9) patients with ≥200 CD4 cell counts had Toxoplasma antibodies (p >0.05).

Detection of toxoplasmic encephalitis in HIV positive patients in urine with hydrogel nanoparticles

BackgroundDiagnosis of toxoplasmic encephalitis (TE) is challenging under the best clinical circumstances. The poor clinical sensitivity of quantitative polymerase chain reaction (qPCR) forToxoplasmain blood and CSF and the limited availability of molecular diagnostics and imaging technology leaves clinicians in resource-limited settings with few options other than empiric treatment.Methology/principle findingsHere we describe proof of concept for a novel urine diagnostics for TE using Poly-N-Isopropylacrylamide nanoparticles dyed with Reactive Blue-221 to concentrate antigens, substantially increasing the limit of detection. After nanoparticle-concentration, a standard western blotting technique with a monoclonal antibody was used for antigen detection. Limit of detection was 7.8pg/ml and 31.3pg/ml ofT.gondiiantigens GRA1 and SAG1, respectively. To characterize this diagnostic approach, 164 hospitalized HIV-infected patients with neurological symptoms compatible with TE were tested for 1)T.gondiiserology (121/147, positive samples/total samples tested), 2) qPCR in cerebrospinal fluid (11/41), 3) qPCR in blood (10/112), and 4) urinary GRA1 (30/164) and SAG1 (12/164). GRA1 appears to be superior to SAG1 for detection of TE antigens in urine. Fifty-one HIV-infected,T.gondiiseropositive but asymptomatic persons all tested negative by nanoparticle western blot and blood qPCR, suggesting the test has good specificity for TE for both GRA1 and SAG1. In a subgroup of 44 patients, urine samples were assayed with mass spectrometry parallel-reaction-monitoring (PRM) for the presence ofT.gondiiantigens. PRM identified antigens in 8 samples, 6 of which were concordant with the urine diagnostic.Conclusion/significancesOur results demonstrate nanoparticle technology’s potential for a noninvasive diagnostic test for TE. Moving forward, GRA1 is a promising target for antigen based diagnostics for TE.

Serological Responses to Toxoplasma gondii and Matrix Antigen 1 Predict the Risk of Subsequent Toxoplasmic Encephalitis in People Living with HIV

Background Clinically 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 protein MAG1, for predicting incident toxoplasmic encephalitis (TE) in people living with HIV (PLWH). Methods We 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 ELISA. Results Two years prior to clinical diagnosis, 68% of TE cases were MAG1_4.2 seropositive compared with 16% of controls (OR 25.0, 95% CI 3.14-199.18). Corresponding results for MAG1_5.2 seropositivity were 36% and 14% (OR 3.6, 95% CI 0.95-13.42). Higher levels of antibody to MAG1_4.2 (OR 18.5 per doubling of the 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. Conclusions Antibodies 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.

Epidemiology, Pathophysiology, Diagnosis, and Management of Cerebral Toxoplasmosis

SUMMARY Toxoplasma gondii is known to infect a considerable number of mammalian and avian species and a substantial proportion of the world’s human population. The parasite has an impressive ability to disseminate within the host’s body and employs various tactics to overcome the highly regulatory blood-brain barrier and reside in the brain. In healthy individuals, T. gondii infection is largely tolerated without any obvious ill effects. However, primary infection in immunosuppressed patients can result in acute cerebral or systemic disease, and reactivation of latent tissue cysts can lead to a deadly outcome. It is imperative that treatment of life-threatening toxoplasmic encephalitis is timely and effective. Several therapeutic and prophylactic regimens have been used in clinical practice. Current approaches can control infection caused by the invasive and highly proliferative tachyzoites but cannot eliminate the dormant tissue cysts. Adverse events and other limitations are associated with the standard pyrimethamine-based therapy, and effective vaccines are unavailable. In this review, the epidemiology, economic impact, pathophysiology, diagnosis, and management of cerebral toxoplasmosis are discussed, and critical areas for future research are highlighted.

Diagnostic value of real-time PCR of brain mass lesion in HIV-associated toxoplasmic encephalitis: a case series

Background Toxoplasmic encephalitis (TE) is a leading cause of brain mass lesions (BML) in human immunodeficiency viruses (HIV)-infected patients. Yet, so far, no accurate diagnostic approach for TE has been developed. Herein, we presented a case series (9 HIV-infected patients with TG confirmed by RT-PCR of BML) to assess the diagnostic value of reverse transcription-polymerase chain reaction (RT-PCR) on TE. Methods A total of 9 HIV-infected patients with TE confirmed by RT-PCR of BML were included in this study. Clinical data, including clinical symptoms, blood and CSF analysis, neuroimaging features, histopathological characteristics, treatment, and prognosis, were assessed in all patients. According to the results of RT-PCR of BML, all the patients received oral administration of trimethoprim-sulfamethoxazole combined with antiretroviral therapy (ART). Patients were followed up by telephone or outpatient service. Results There were 8 male and 1 female patients; their age ranged from 26 to 56 years-old. The main symptom was intracranial hypertension (6/9). Six patients presented multiple brain lesions, which were mainly located in the supratentorial area (7/9). CD4+ count ranged from 11 to 159 cells/μl (median 92 cells/μl), and serological HIV viral load 0–989190 copies/ml (median 192836 copies/ml). IgG and IgM against serum TG were positive in 7 and 1 patients, respectively. Moreover, regarding CSF, IgG against TG was positive in 3 patients, while all patients were negative for IgM. The neuroimaging features on MRI showed no specificity. Four patients were diagnosed with TE by histopathological findings. After receiving anti-Toxoplasma therapy, 8 (8/9) patients improved clinically to a considerable extent. Conclusions The application of RT-PCR of BML, together with conventional methods, may significantly improve the diagnostic efficiency of TE.