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PubMed2000

Comparison of PCR detection methods for B1, P30, and 18S rDNA genes of T. gondii in aqueous humor.

PURPOSE: Comparison of polymerase chain reaction (PCR) amplification of three Toxoplasma gondii genes in aqueous humor. METHODS: Nested PCRs carried out using published methods were optimized for maximum sensitivity and specificity. Five pairs of oligonucleotide primers, directed against the B1, P30, and ribosomal genes, were used and compared to determine which sequences were most effective in detecting T. gondii DNA. Methods were developed with DNA templates in water and were subsequently applied to both normal and inflamed aqueous. RESULTS: After one round of PCR amplification, P30 and ribosomal primers were able to detect 1 pg genomic T. gondii DNA. However, those directed against the B1 gene were able to detect 50 fg (approximately single tachyzoite). This level of sensitivity was also achieved using the P30 primers after a second round of PCR; however, only primers based on the B1 gene maintained this level of sensitivity in both normal and inflamed aqueous. B1-specific primers did not amplify sequences from fungal, bacterial, or human lymphocyte DNA. The sensitivity of T. gondii detection using B1 gene-specific primers was not compromised when large amounts of human lymphocyte DNA were present, and application to an ocular sample or retinal section from patients with toxoplasma chorioretinitis was successful in confirming the presence of T. gondii DNA. CONCLUSIONS: The B1 PCR protocol appears to be the most sensitive protocol in the detection of T. gondii DNA and has been successful in identification of T. gondii DNA in ocular fluids and retinal sections. This provides direct evidence of the presence of T. gondii within the eye and may therefore help in the management of toxoplasma retinochoroiditis.

Animals↗

PubMed1999

Pathogenesis of toxoplasmic retinochoroiditis.

The protozoan parasite Toxoplasma gondii is an important cause of ocular disease both in immunosuppressed and immunocompetent individuals. Non-ocular infections are not usually serious in otherwise healthy adults. In contrast, toxoplasmic retinochoroiditis is a progressive, recurring disease that can cause severe morbidity. Here, Fiona Roberts and Rima McLeod review the demography, pathology and clinical findings of this disease. They discuss mechanisms of retinal destruction and disease recurrences, and the local immunological response at this immune-privileged site.

Animals↗

PubMed1991

Neuro-ophthalmic manifestations of human immunodeficiency virus infection.

Both the afferent visual pathways and ocular motor system may be affected by human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome (AIDS). Coexisting infections and neoplastic processes in the eye and brain create a diagnostic challenge for the clinician. This article discusses neuroophthalmic manifestations associated with HIV and AIDS, with emphasis on clinical presentation, diagnosis, and treatment.

Acquired Immunodeficiency Syndrome↗

PubMed2006

Effect of highly active antiretroviral therapy (HAART) on the natural history of ocular manifestations in HIV-infected children.

PURPOSE: To determine the effect of highly active antiretroviral therapy (HAART) on the natural history of ocular manifestations in HIV-infected children. METHODS: All of the HIV-infected children attending the Institute of Pediatrics, University of Milan, Milan, Italy, between 1982 and 2004 were studied. Every 3 months, they were physically examined and underwent indirect fundoscopy conducted by an experienced ophthalmologist; if diagnosed as having eye disease, they were evaluated by the ophthalmologist every week while on specific therapy and monthly thereafter. The clinical and laboratory findings before and after the introduction of HAART were compared. RESULTS: The cohort consisted of 117 HIV-infected children (61 males), with a follow-up ranging from 0.09 to 22.31 years (median, 16.33 years). A total of nine cases of ocular involvement (7.7%) were diagnosed between 1983 and 1994, before the introduction of HAART. All nine children died 4-24 months (median, 15 months) after the diagnosis of ophthalmic disease. No case of ocular involvement was observed after the introduction of HAART (P=0.011 vs. before HAART). CONCLUSION: The introduction of HAART has had a significant impact on the natural history of ocular manifestations in HIV-infected children, thus suggesting that a reduction in the frequency of ophthalmologic follow-up should be considered for HAART-treated HIV-infected children with immune reconstitution and no visual symptom.

AIDS-Related Opportunistic Infections↗

PubMed1988

[Ocular pathology in AIDS and related syndromes].

AIDS is characterised by the onset of opportunistic infections and/or neoplasms usually of the lungs, digestive tract and CNS. Eye involvement is less common but takes the form of Kaposi's sarcoma on the eyelids and conjunctiva and retinitis that may be aspecific or caused by CMV or T gondii. Treatment with Interferon, and sequential antifolic and antiviral drugs is effective but the prognosis for the underlying disease remains poor.

AIDS-Related Complex↗

PubMed2006

Prevalence of anti-Toxoplasma gondii antibodies in serum and aqueous humor samples from cats with uveitis or systemic diseases in France.

Anti-Toxoplasma gondii antibodies were determined in serum and aqueous humor of two groups of cats in France: cats with uveitis (group 1, n=26) and cats with systemic disease (group 2, n=24) using an agglutination test. Titres above 1:64 were considered positive. IgG antibodies to T. gondii were detected in 10 serum samples from group 1 and in 10 serum samples from group 2, and in 2 aqueous humor samples from group 1 and in 1 aqueous humor samples from group 2. The distribution of ocular lesions according to the serological status of the animals indicated that lens luxation and buphthalmia were more frequent in T. gondii seropositive cats than in seronegative ones. The study reports a similar prevalence of anti-T. gondii antibodies in cats with uveitis and in cats without uveitis in France. Serological results must be analysed carefully and additional diagnostic tools is required.

Agglutination Tests↗

PubMed2003

Presence of a 88 kDa Eales protein in uveitis, tuberculosis, leprosy and rheumatoid arthritis.

BACKGROUND: Eales disease (ED) is an idiopathic retinal vasculitis affecting young adult males. We have earlier reported the identification, purification and partial characterization of a novel 88 kDa protein found in the serum of patients with ED. The aim of the present study was to look for the 88 kDa protein in serum samples obtained from cases of retinal vasculitis mimicking ED and in other systemic inflammatory diseases. MATERIAL/METHODS: Serum samples from healthy volunteers and from patients with ED, uveitis, parsplanitis ocular sarcoidosis, toxoplasmosis, leprosy, diabetic retinopathy, viral hepatitis, and rheumatoid arthritis were analyzed for the presence of the 88 kDa protein by polyacralymide gel electrophoresis (PAGE). The immunological identity of the 88 kDa protein found in ED and in other diseases was investigated by Western blot. Immunohistochemistry was performed on epiretinal membranes (ERM) obtained from ED patients to localize the 88 kDa protein. RESULTS: 88 kDa protein were detected in serum samples obtained from patients with posterior uveitis, tuberculosis, leprosy and rheumatoid arthritis. The 88 kDa protein found in serum from patients with ED is immunologically identical to that found in other systemic inflammatory conditions. 88 kDa protein was localized in inflammatory cells and in nonvascular endothelium in ERMs obtained from patients with ED. CONCLUSIONS: We have identified a novel acute phase reactant, which is elaborated in ocular and systemic inflammatory conditions other than Eales disease. Further work is necessary to decipher the precise role of the 88 kDa protein in the pathophysiology of these inflammatory diseases.

Adult↗

PubMed1990

Intraocular in vivo immunofluorescence. A new technique for visualizing structures of the ocular fundus.

A new noninvasive technique for observing structures in the living eye has been developed: the technique is based on intravenous application of specific antibodies, labeled with fluorescein. The immunologically marked substructures of the fundus of the eye, the only transparent organ in mammals, are photographed directly using high speed film. Combined with a digital image processor to enhance low contrast contours, this technique can be used for diagnostic purposes, as shown in rabbits with experimental toxoplasmic chorioretinitis.

Animals↗

PubMed1998

Analysis of immunoregulatory cytokines in ocular fluid samples from patients with uveitis.

PURPOSE: To investigate the T-helper cell cytokine profiles in two well-defined clinical uveitis entities caused by an infectious mechanism. METHODS: Cytokines (interleukin [IL]-2, IL-4, IL-6, IL-10, and interferon [IFN]-gamma) were measured in ocular fluid samples obtained from patients with herpes simplex- or varicella-zoster virus-induced acute retinal necrosis (ARN; n = 17) and toxoplasma chorioretinitis (n = 27) using enzyme-linked immunosorbent assay techniques. The data were compared with data for 51 control samples taken during cataract surgery (n = 10), vitrectomy in diabetic retinopathy (n = 10), eye bank eyes (n = 10) and with samples from patients with "autoimmune" uveitis (n = 21). RESULTS: Interleukin-6 was detected in 44 of 51 control samples and 43 of 44 eyes of patients with uveitis. The highest levels in the control samples were detected in 9 of 10 vitreous samples from patients with diabetic retinopathy (mean, 648 pg/ml). In 8 of 10 samples taken from patients during cataract surgery and in 7 of 10 eye bank eyes the amount of IL-6 was significantly lower (mean, 10 pg/ml and 136 pg/ml, respectively). Interleukin-6 levels in patients with ARN (mean, 1436 pg/ml) were significantly higher than in those with toxoplasma chorioretinitis (mean, 272 pg/ml). Interleukin-2 was detected in one of the samples from patients with toxoplasma chorioretinitis (1105 pg/ml) and in three samples from the control subjects suffering from Fuchs' heterochromic anterior uveitis (mean, 752 pg/ml). No IL-4 (<2 pg/ml) was detected either in patient or control samples. Interferon-gamma could be detected in 7 of 17 ARN patients (range, 277-3483 pg/ml), in 13 of 27 samples from patients with toxoplasma chorioretinitis (range, 12-250 pg/ml), and in 1 of 21 of the samples from control subjects with uveitis (31 pg/ml) but was absent in nonuveitic control samples. Interleukin-10 was detected in 10 of 17 ARN patients (range, 29-3927 pg/ml), in 13 of 27 samples from patients with toxoplasma chorioretinitis (range, 4-67 pg/ml), and in only 3 of 51 control samples (6 pg/ml, 16 pg/ml, and 20 pg/ml). CONCLUSIONS: Various immunoregulatory cytokines (IL-6, IL-10, and IFN-gamma) were detected in ocular fluid samples from patients with uveitis. A separate role for either a T-helper type 1 or T-helper type 2 response in the pathogenesis of clinical uveitis could not be proven.

Animals↗

PubMedDate not supplied

[Chorioretinitis caused by toxoplasma in children].

In a period of 5 years, 21 children with ocular lesions caused by toxoplasma (chorioretinitis due to toxoplasma) were seen at "Pedro Kourí" Tropical Medicine Institute. Of the 21 children, 5 (23.8%) had lesions in both eyes and 16 (76.1%) in one eye (9 in the left eye and 7 in the right one). 9 children (42.8%) initially had active lesions that responded satisfactorily to medical treatment whereas 12 (57.1%) came to the hospital with healed lesions that did not require any treatment. They were all followed up as outpatients with favorable evolution in all cases.

Adolescent↗

PubMed2006

Chronic ocular lesions in tawny owls (Strix aluco) injured by road traffic.

The chronic ocular lesions suffered by 50 tawny owls (Strix aluco) injured by road traffic were investigated. They included non-healing corneal erosions, cataracts and retinal scarring, and periretinal membrane formation. The intraocular pressure was significantly lower in the eyes with intraocular inflammatory pathology and higher in the eyes with irido- or cyclodialysis than in ophthalmically normal eyes. Cicatritial retinal lesions were not associated with high titres of antibodies to Toxoplasma species. The findings correlate with those observed in human beings with eye injuries due to high-speed blunt trauma.

Animals↗

PubMed1986

The ultrastructural pathology of congenital murine toxoplasmic retinochoroiditis. Part I: The localization and morphology of Toxoplasma cysts in the retina.

This study describes the ultrastructural characteristics of retinal parasitization by Toxoplasma gondii in a congenital mouse model. Forty-two eyes from infected mice, 18-22-weeks-old, and 24 control eyes were initially studied by light microscopy of semithin sections. Twenty-six eyes from infected animals and six from the controls were further investigated by transmission electron microscopy. A total of 13 Toxoplasma cysts was found in samples of the retinas of six eyes from five infected animals. These were located in the inner retina, particularly the ganglion-cell layer, but in no other ocular tissue. The cyst wall interdigitated with the host cell which in most cases was probably glial in origin (Müller cell). Two cysts showed evidence of parasitization of neural cells. The individual Toxoplasma cystozoites demonstrated characteristic ultrastructural features. There was no evidence of morphological changes indicative of toxicity to surrounding retinal tissues, and the associated inflammatory cell reaction (described in Dutton, McMenamin, Hay and Cameron, 1986b) was remote from the parasite. There was no morphological evidence of rupture or degeneration of cysts. No free parasites (endozoites) or pseudocysts were observed.

Animals↗

PubMed1978

Rhegmatogenous retinal detachment following chorioretinal inflammatory disease.

Preexisting ocular inflammatory disease was responsible for 44 cases (1.7%) of rhegmatogenous retinal detachment in a large series of consecutive retinal detachments. Characteristics of retinal detachments following ocular inflammatory disease include a longer duration of the detachment, fewer observable retinal breaks, a higher incidence of visible vitreous membranes and preoperative macular puckers, a younger age distribution, and a higher incidence of phakic patients. In comparing the group of postinflammatory rhegmatogenous retinal detachments with detachments not associated with inflammation, the following characteristics did not show any statistically significant difference: sex, the eye involved, the status of the ciliary epithelium, the presence or types of retinal folds, the rate of operative complications, or the rate of reattachment at six months.

Adult↗

PubMed2003

Toxoplasma infection in selected patients in Kathmandu, Nepal.

Seroprevalence of Toxoplasma infections in 272 patients with ocular diseases (uveitis, retinochoroiditis), malignancy (including leukemia), women with bad obstetric history (BOH) and others (patients with fever, lymphadenitis and encephalitis) have been was studied. Toxoplasma antibodies were detected by microlatex agglutination and IgM ELISA techniques. Overall, 50.7% (138/272) patients included in this study had Toxoplasma antibodies, out of which 5.7% (8/138) had IgM antibodies. Patients with malignancy had highest positive rate [68.7% (22/32)] followed by group of others. Of the different groups, women with BOH had highest Toxoplasma IgM positive rate [25.0%; (2/8)].

Animals↗

PubMed1995

Ocular manifestations of AIDS.

AIDS causes severe depression of the immune system through selective infection of CD4+ T lymphocytes. As such, certain infections and neoplasms occur in these patients often with ocular involvement. Among these, cytomegalovirus retinitis is by far the most common and remains a leading cause of visual loss. Intravenous ganciclovir and foscarnet, the two Food and Drug Administration-approved treatments for cytomegalovirus retinitis, are effective in most cases, but recurrences are the rule. In addition, these virustatic drugs require lifelong administration and dose-limiting toxicity affects many of these patients. Ongoing investigation into current and alternative therapies has produced some promising developments which are discussed here. Also reviewed are recent findings associated with other opportunistic pathogens and neoplasms that affect the eye in AIDS, including varicella-zoster virus, Toxoplasma gondii, and lymphoma.

AIDS-Related Opportunistic Infections↗

PubMed2000

Intraocular antibody production in intraocular inflammation.

BACKGROUND: The production of intraocular antibodies is considered a specific marker for active infectious uveitis. The aim of our study was to evaluate the diagnostic value of aqueous humor analysis in consecutive patients referred to a tertiary clinical center. METHODS: We analyzed 91 paired aqueous humor/serum samples from 89 patients with intraocular inflammation. In 71 patients aqueous humor analysis was used as a positive or negative confirmation of the suspected cause, whereas in 18 patients the clinical diagnosis was completely uncertain. A modified micro-ELISA technique was used to detect intraocular IgG production against Toxoplasma gondii, varicella zoster virus, herpes simplex virus and cytomegalovirus. Statistical analysis was performed using the "Cohen's kappa" test. RESULTS: Specific intra-ocular antibody production could be detected in 12 (66.7%) of 18 patients with uncertain diagnosis. Subsequently initiated therapy led to clinical improvement in 10 patients, whereas 2 patients remained unchanged. In 2 (2.8%) of 71 patients aqueous humor analysis led to revision of the initially suspected etiology and to a change of therapy. Statistical analysis showed a significant accordance of diagnosis and aqueous humor analysis (P<0.01). CONCLUSION: In patients with infectious uveitis, analysis of intraocular synthesis of specific antibodies is a valuable tool to establish the etiology rapidly and allows initiation of targeted antimicrobial treatment.

Antibodies, Protozoan↗

PubMed1998

Effects of drug therapy on Toxoplasma cysts in an animal model of acute and chronic disease.

PURPOSE: To evaluate the effects of drug therapy on the clinical course of acute acquired Toxoplasma retinochoroiditis and on the number of Toxoplasma cysts present in the brain and ocular tissues in the hamster animal model. METHODS: The Syrian golden hamster animal model of Toxoplasma retinochoroiditis was used. In acute disease, systemically administered atovaquone was compared with conventional therapies (pyrimethamine combined with sulfadiazine; clindamycin; and spiramycin). The clinical course of the ocular disease was determined with retinal examination and photography of the fundus. The number of Toxoplasma cysts remaining after treatment was evaluated in aliquots of brain homogenate and in retinal tissue. The effect of atovaquone on cerebral Toxoplasma cyst count was also studied in chronic disease. RESULTS: None of the drugs administered altered the course of the acute disease, judged by clinical examination. Atovaquone alone significantly reduced the number of cerebral Toxoplasma cysts after acute disease. Atovaquone also significantly reduced the cerebral Toxoplasma cyst count in chronic disease. CONCLUSIONS: Tissue cysts are believed to be responsible for reactivation of Toxoplasma retinochoroiditis. Atovaquone has the potential to reduce the risk of recurrent disease.

Acute Disease↗

PubMed2003

Toxoplasma gondii retinochoroiditis after cardiac transplantation.

PURPOSE: To report 4 cases of Toxoplasma gondii retinochoroiditis in patients having recently undergone cardiac transplantation. METHODS: Review of medical records for 4 patients presenting retinochoroiditis and evidence of T. gondii infection. RESULTS: Patient ranged in age from 25 to 53 years. Ocular symptoms began between 3 and 6 months after transplantation. All patients were under immunosuppressive therapy. Foci of retinochoroiditis were observed unilaterally in three patients and bilaterally in one. Intraocular inflammation was minimal in all cases. Serologic responses were highly suggestive of T. gondii as the etiology in all cases; other causes (CMV retinitis and syphilis) were actively sought and were not found. All patients underwent classic therapy. The three unilateral cases evolved favorably, but the bilateral case, seen late, showed extensive macular scarring. CONCLUSION: Infectious retinochoroiditis is a potentially blinding complication seen after cardiac transplantation, justifying close clinical and serological surveillance or, in certain cases such as mismatched donors, anti-parasitic prophylaxis.

Adult↗