The value of routine polymerase chain reaction analysis of intraocular fluid specimens in the diagnosis of infectious posterior uveitis.

OBJECTIVE: To assess the value of routine polymerase chain reaction (PCR) analysis on intraocular fluid from patients presenting with a first episode of suspected active infectious posterior uveitis in a population with a high prevalence of human immunodeficiency virus infection. DESIGN: Retrospective, interventional case series. Participants. 159 consecutive patients presenting at a tertiary care hospital over a five-year period. METHODS: PCR analysis was performed for cytomegalovirus, varicella zoster virus, herpes simplex virus types 1 and 2, Toxoplasma gondii, and Mycobacterium tuberculosis. RESULTS: PCR analysis confirmed the initial clinical diagnosis in 55 patients (35%) and altered the initial clinical diagnosis in 36 patients (23%). The clinical diagnosis prior to PCR testing was nonspecific (uncertain) in 51 patients (32%), with PCR providing a definitive final diagnosis in 20 of these patients (39%); necrotizing herpetic retinopathy and ocular toxoplasmosis were particularly difficult to diagnose correctly without the use of PCR analysis. CONCLUSION: The clinical phenotype alone was unreliable in diagnosing the underlying infectious cause in a quarter of patients in this study. Since the outcome of incorrectly treated infective uveitis can be blinding, PCR analysis of ocular fluids is recommended early in the disease even in resource poor settings.

Interleukin 17A as an effective target for anti-inflammatory and antiparasitic treatment of toxoplasmic uveitis.

BACKGROUND: Toxoplasmosis is the most common cause of posterior uveitis in immunocompetent subjects. The requirement of limiting both parasite multiplication and tissue destruction suggests that the balance between T-helper (Th) 17 and T-regulatory cells is an important factor in toxoplasmosis-induced retinal damage. METHODS: In a prospective clinical study of acute ocular toxoplasmosis, we assessed the cytokine pattern in aqueous humors of 10 affected patients. To determine the immunological mechanisms, we evaluated intraocular inflammation, parasite load, and immunological responses using messenger RNA and protein levels in a mouse model. Anti-interleukin 17A (IL-17A) monoclonal antibodies (mAbs) were administered with the parasite to evaluate the role of IL-17A. RESULTS: Severe ocular inflammation and cytokine patterns comparable to human cases were observed, including IL-17A production. Neutralizing IL-17A decreased intraocular inflammation and parasite load in mice. Detailed studies revealed up-regulation of T-regulatory and Th1 pathways. When interferon γ (IFN-γ) was neutralized concomitantly, the parasite multiplication rate was partially restored. CONCLUSIONS: Local IL-17A production by resident cells plays a central role in the pathology of ocular toxoplasmosis. The balance between Th17 and Th1 responses (especially IFN-γ) is crucial for the outcome of infection. This data reveals new in vivo therapeutic approaches by repressing inflammatory pathways using intravitreal injection of IL-17A mAbs.

Ocular manifestations of systemic disease: toxoplasmosis.

PURPOSE OF REVIEW: To provide an overview of ocular toxoplasmosis, the leading cause of infectious posterior uveitis, focusing on recent trends of disease epidemiology, pathogenesis, diagnosis, therapy and prevention. RECENT FINDINGS: Novel aspects of epidemiology, including growing importance of water transmission are discussed. The historical controversy of congenital versus postnatally acquired toxoplasmosis is revisited. Recent insights into pathogenesis of ocular toxoplasmosis are also reviewed, tipping the delicate balance between parasite virulence and host immunity. Diagnosis of ocular toxoplasmosis is also discussed in the light of serological, molecular and imaging tools. Finally, a critical analysis of current and emerging therapies for ocular toxoplasmosis is made. Preventive aspects are also commented upon. SUMMARY: Waterborne toxoplasmosis is increasingly recognized in outbreaks and in endemic areas. The importance of postnatally acquired toxoplasmosis is now well established, but should not lead to underestimation of congenital disease. Genetic determination of parasite virulence/individual susceptibility might correlate with disease outcomes. Serological, molecular and imaging tools may improve the diagnosis and follow-up of individuals with ocular toxoplasmosis. Despite emergence of alternative therapeutic regimens, including intravitreal antibiotics, classical therapy with sulfadiazine/pyrimethamine is still standard for toxoplasmic retinochoroiditis. Adequate prophylaxis is expected to have an effect in ocular burden of toxoplasmosis.

Real-time polymerase chain reaction and intraocular antibody production for the diagnosis of viral versus toxoplasmic infectious posterior uveitis.

PURPOSE: The aim of this work was to determine the diagnostic performance of real-time polymerase chain reaction (RT-PCR) and to assess intraocular specific antibody secretion (Goldmann-Witmer coefficient) on samples from patients with signs of posterior uveitis presumably of infectious origin and to target the use of these two biologic tests in the diagnostic of Toxoplasma/viral Herpesviridae posterior uveitis by the consideration of clinical behavior and delay of intraocular sampling. METHODS: Aqueous humour and/or vitreous fluid were collected from patients suspected of having posterior uveitis of infectious origin at presentation (140 samples). The diagnosis was confirmed by quantification of antibodies with the Goldmann-Witmer coefficient (GWC) and for detection of Herpesviridae and Toxoplasma gondii genomes with RT-PCR. Forty-one patients had final diagnosis of uveitis of non-Toxoplasma/non-viral origin and 35 among them constituted the control group. The main outcome measures were sensitivity, specificity, and positive and negative predictive values (PPV and NPV). RESULTS: When pre-intraocular testing indication was compared with final diagnosis, GWC was a more sensitive and specific method than RT-PCR, and was successful in detecting T. gondii, especially if the patient is immunocompetent and the testing is carried out later in the disease course, up to 15 months. For viral Herpesviridae uveitis, the sensitivity and PPV of PCR evaluation was higher than detected with GWC with respectively 46% compared with 20% for sensitivity and 85% versus 60% for PPV. In either viral retinitis or toxoplasmosis infection, RT-PCR results were positive from 24 h, although GWC was not significant until 1 week after the onset of signs. In toxoplasmosis patients, positive RT-PCR results were statistically correlated with the chorioretinitis area (more than three disc areas; p = 0.002), with the age older than 50 (p = 0.0034) and with a clinical anterior inflammation (Tyndall ≥1/2+) and panuveitis; (p = 0.0001). CONCLUSIONS: For the diagnosis of viral or toxoplasmosis-associated intraocular inflammation, the usefulness of laboratory diagnosis tools (RT-PCR and GWC) depends on parameters other than the sensitivity of the tests. Certain patient characteristics such as the age of the patients, immune status, duration since the onset of symptoms, retinitis area, predominant site and extent of inflammation within the eye should orientate the rational for the choice of laboratory testing in analysis of intraocular fluids.

Clinical manifestations and visual outcomes associated with ocular toxoplasmosis in a Brazilian population.

Ocular toxoplasmosis is the leading cause of posterior uveitis worldwide. We conducted an observational study of 262 consecutive individuals (n = 344 eyes) with ocular toxoplasmosis who were followed over a 34-month period. Most subjects were T. gondii IgG + /IgM- (n = 242; 92.4%; 317 eyes), and 140 eyes (40.7%) had active lesions. For eyes in which retinal lesions were active at recruitment and best-corrected visual acuity (BCVA) could be measured (n = 133), 21.0% (n = 28) remained blind (BCVA below 20/400) after inflammation resolved. In these eyes, atypical ocular toxoplasmosis (OR 4.99; 95% CI 1.14-22.85; p = 0.0330), macular lesion (OR 9.95; 95% CI 2.45-47.15; p = 0.0019) and any complication (OR 10.26; 95% CI 3.82-30.67; p < 0.0001) were associated with BCVA below 20/200. For eyes with only inactive lesions at recruitment and BCVA measured (n = 178), 28.1% (n = 50) were blind. In these eyes, having at least one lesion larger than one disc-diameter (OR 6.30; 95% CI 2.28-22.46; p = 0.0013) and macular lesion (OR 5.69; 95% CI 2.53-13.54; p < 0.0001) were associated with BCVA below 20/200. Older age (OR 1.02; 95% CI 1.00-1.05; p = 0.0493) and active disease at presentation (OR 4.74; 95% CI 1.95-12.91; p = 0.0011) were associated with recurrences. Additional clinical attention should be directed towards patients with risk factors for poor visual outcome.

Anti-Toxoplasma gondii secretory IgA in tears of patients with ocular toxoplasmosis: immunodiagnostic validation by ELISA.

Toxoplasma gondii causes posterior uveitis and the specific diagnosis is based on clinical criteria. The presence of anti-T. gondii secretory IgA (sIgA) antibodies in patients' tears has been reported and an association was found between ocular toxoplasmosis and the anti-T. gondii sIgA isotype in Brazilian patients. The purpose of this study was to provide an objective validation of the published ELISA test for determining the presence of anti-T. gondii sIgA in the tears of individuals with ocular toxoplasmosis. Tears from 156 patients with active posterior uveitis were analysed; 82 of them presented characteristics of ocular toxoplasmosis (standard lesion) and 74 patients presented uveitis due to other aetiologies. Cases of active posterior uveitis were considered standard when a new inflammatory focus satellite to old retinochoroidal scars was observed. The determination of anti-T. gondii sIgA was made using an ELISA test with crude tachyzoite antigenic extracts. Tears were collected without previous stimulation. Detection of sIgA showed 65.9% sensitivity (95% CI = 54.5-74.4), 71.6% specificity (95% CI = 59.8-81.2), a positive predictive value of 72% (95% CI = 60.3-81.5) and a negative predictive value of 65.4% (95% CI = 54.0-75.4). sIgA reactivity was higher in the tears of patients with active posterior uveitis due to T. gondii (p < 0.05). The test is useful for differentiating active posterior uveitis due to toxoplasmosis from uveitis caused by other diseases.

Primary Ocular Toxoplasmosis Presenting to Uveitis Services in a Non-endemic Setting.

PURPOSE: This study sought to describe the different clinical features and presentations of primary ocular toxoplasmosis in a setting not demonstrating an outbreak of disease. METHODS: This was a retrospective review of patients presenting to uveitis management services in Auckland and Hamilton, New Zealand between 2003 to 2018 with uveitis and positive toxoplasmosis immunoglobulin M serology. RESULTS: We identified 16 patients with primary acquired toxoplasmosis infection and ocular involvement. The mean age was 53 years. Systemic symptoms were reported in 56% (9 / 16). Visual acuity was reduced to 20 / 30 or less in 50% of patients (8 / 16). A single focus of retinitis without a pigmented scar was the salient clinical feature in 69% (11 / 16). Optic nerve inflammation was the sole clinical finding in 19% (3 / 16). Bilateral arterial vasculitis was the sole clinical finding in 13% (2 / 16). A delay in the diagnosis of toxoplasmosis of more than two weeks occurred in 38% (6 / 16) due to an initial alternative diagnosis. Antibiotic therapy was prescribed in all cases. Vision was maintained or improved in 69% (11 / 16) at the most recent follow-up visit (15 months to 10 years). Relapse occurred in 69% (11 / 16), typically within four years from the initial presentation. CONCLUSIONS: Primary ocular toxoplasmosis presenting in adulthood is a relatively uncommon cause of posterior uveitis in New Zealand. This condition should be considered in any patient presenting with retinitis or optic nerve inflammation without a retinochoroidal scar. This disease tends to relapse; thus, close follow-up is required.

Usefulness of aqueous humor analysis for the diagnosis of posterior uveitis.

PURPOSE: To assess the clinical usefulness of aqueous fluid analysis for the diagnosis and treatment of patients suspected of having infectious posterior uveitis (PU). DESIGN: Case-control study. PARTICIPANTS: From 2002 through 2005, 152 eyes from 152 patients with active PU (16 of whom were immunosuppressed) underwent diagnostic aqueous testing. As controls, 20 patients with Fuchs' heterochromic uveitis and 20 patients with age-related cataract were included. METHODS: Aqueous samples were examined by real-time polymerase chain reaction (PCR) and by pathogen-specific analysis of intraocular antibody production (Goldmann-Witmer coefficient [GWC]) for herpes simplex virus (HSV), varicella zoster virus (VZV), cytomegalovirus (CMV), and the parasite Toxoplasma gondii. MAIN OUTCOME MEASURES: Results of aqueous analysis and any adverse effects of aqueous sampling. Correlations between the results of aqueous testing and clinical characteristics as well as the treatment of patients. RESULTS: Of 152 patients, 44 (29%) had positive results for at least one diagnostic assay (37/136 [28%] immunocompetent and 7/16 [44%] immunocompromised patients). None of the controls had positive results using PCR or GWC. A positive result was obtained predominantly in patients with focal chorioretinitis (37/87 [40%]) and in extensive retinitis (7/9 [78%]), whereas in multifocal chorioretinitis, neuroretinitis, and retinal vasculitis only a few samples demonstrated positive results (2/19, 1/29, and 0/10, respectively). Of 37 immunocompetent PU patients with positive results, 28 (76%) cases were caused by T. gondii, whereas viral infections were most common in immunocompromised patients (5/7 [71%]). In immunocompetent and toxoplasmosis PU patients, GWC was the most informative assay (34/37 [92%] and 28/30 [93%], respectively), in contrast to immunosuppressed patients (PCR positive in 5/7 and GWC positive in 4/7). Independent of the immune status of patients, positive PCR results were observed more frequently in viral infections than in toxoplasmosis (P<0.001). As a consequence of aqueous analysis, change of treatment was necessary in 36 patients (24%). None of the patients experienced complications during or after aqueous sampling. CONCLUSIONS: Despite the posterior location of inflammation, aqueous analyses with PCR and GWC for HSV, VZV, CMV, and T. gondii revealed an infectious cause in 29% of patients with PU.

Diagnosis of ocular toxocariasis by establishing intraocular antibody production.

PURPOSE: To investigate the role of Toxocara canis in posterior uveitis of undetermined origin. DESIGN: Retrospective case-study. METHODS: Paired ocular fluid (47 aqueous humor [AH] and two vitreous fluids) and serum samples of 37 adults and 12 children with undetermined posterior uveitis were retrospectively analyzed for intraocular IgG antibody production against Toxocara canis by enzyme-linked immunosorbent assay and Goldmann-Witmer coefficient (GWC) determination. Previous diagnostic investigation by polymerase chain reaction and GWC for Herpes simplex virus, Varicella zoster virus, and Toxoplasma gondii had not provided a cause of the posterior uveitis. RESULTS: Three of 12 (25%) children showed intraocular IgG production against Toxocara canis. One child had vitritis, one presented with a low-grade uveitis and a peripheral retinal lesion, and the third had posterior uveitis and a chorioretinal scar. All three children had AH IgG titers exceeding those of the corresponding serum. In fact, two children had low Toxocara serum IgG titers (<1:32) and would have been considered seronegative upon routine serology screening. Intraocular antibody production against Toxocara canis was absent in all 37 adults, including five seropositive patients. CONCLUSIONS: Our results indicate that ocular toxocariasis is mainly a pediatric disease. Serological screening is not informative for the diagnosis of intraocular Toxocara infection. Toxocara GWC analysis, however, can be of value when diagnosing patients with posterior focal lesions or vitritis of unknown etiology.

[Clinical characteristics of 64 individuals carrying active posterior presumptively toxoplasmic uveitis, in Pernambuco]. / Características clínicas de 64 indivíduos portadores de uveítis posterior activa presumiblemente toxoplásmica en Pernambuco.

PURPOSE: To describe clinical characteristics of posterior active uveitis presumptively by Toxoplasma gondii (PAUPT) in patients with typical lesion. Tranversal study. METHODS: Sixty-four patients with retinochoroiditis scatter and active satellite lesions examined in Pernambuco, Brazil. All were older than 10 years and immunocompetent. Gender, age, skin color, and residence were recorded. Previous uveitis, visual accuracy, intraocular pressure (IOP), and ocular examination were analyzed. RESULTS: 52% were males, most of them with white skin (68.8%). Mean age 29 years (+/-10.87). Eighty-four percent of the patients lived in the metropolitan area. 56.2% were having the first episode of uveitis. In the damaged eye, visual accuracy mean was 20/200, IOP mean 14.5 mmHg (+/-64). Hyperemia of the conjunctiva was observed in 29.7% of the patients and alterations of the cornea in 51.6%. There were cells in the aqueous humor in 62.7%. 6.2% had posterior synechiae. All had vitreous damage and 45.3% retinal vasculitis. In 42.2% of the patients, lesions were located in zone I of Holland and 90.6% had the size of one discus diameter or greater. Neuritis was observed in 28.2%. Uveitis was more frequent in the right eye (54.7%). CONCLUSION: PAUPT affects young people and the main symptom was reduction of visual acuity. IOP mean was normal. Alterations of the vitreous were observed in all cases. Injuries were equal to one discus diameter or greater and located in zone I of Holland.

POSTERIOR UVEITIS OR WET AGE-RELATED MACULAR DEGENERATION? CASE REPORT.

We present the case of a 61-year-old patient without previous ophthalmic or general history, who developed unilateral posterior pole granuloma and was diagnosed with posterior uveitis most likely due to a systemic Toxocara canis infection. Clinical examination and ancillary investigations showed elements that were also consistent with wet ARMD, but laboratory tests and successful use of oral anti-helminthic and corticosteroid therapy in decreasing the macular lesion and improving visual acuity, confirmed the diagnosis of posterior uveitis.

Real-time quantitative polymerase chain reaction diagnosis of infectious posterior uveitis.

OBJECTIVE: To validate a real-time polymerase chain reaction (PCR) assay allowing rapid and sensitive detection and quantitation of 4 common infectious posterior uveitis pathogens. METHODS: A real-time PCR assay using previously validated primer sets for cytomegalovirus, herpes simplex virus, varicella-zoster virus, and Toxoplasma gondii was developed. A standard curve for quantitation of pathogen load was generated for each pathogen using SYBR Green I fluorescence detection. Ocular samples from patients with posterior uveitis and from negative control samples were assayed and compared with standards to identify pathogens and quantify infectious load. RESULTS: Sensitivity for detection of purified pathogen DNA by PCR was not reduced by application of the real-time method. Standard curves for the quantitation of pathogen loads showed sensitivity to fewer than 10 organisms for all pathogens. The technique was applied to 2 clinical problems. First, sensitivities of existing monoplex and multiplex PCR were compared by real-time PCR. No significant difference in sensitivity was observed between multiplex and monoplex techniques. Second, pathogen loads of vitreous specimens from patients previously diagnosed as having infectious posterior uveitis were calculated. Pathogen loads were found to be generally higher for patients with disease caused by varicella-zoster virus than those caused by cytomegalovirus or herpes simplex virus. CONCLUSIONS: Real-time PCR may be applied to infectious agents responsible for posterior uveitis. This technique will likely prove useful for the diagnosis of posterior uveitis as well as the linkage of pathogen to disease. CLINICAL RELEVANCE: Real-time PCR provides a rapid technique for quantitatively evaluating ocular samples for the presence of infectious pathogens.

Validation of a diagnostic multiplex polymerase chain reaction assay for infectious posterior uveitis.

OBJECTIVE: To validate a multiplex polymerase chain reaction (PCR) assay capable of simultaneously screening vitreous biopsy specimens for a panel of common pathogens in posterior uveitis. METHODS: A multiplex PCR assay using novel primer sets for cytomegalovirus (CMV), herpes simplex virus (HSV), varicella zoster virus (VZV), and Toxoplasma gondii was developed. The sensitivity of the assay was determined for purified pathogen DNA. Twenty-one vitreous specimens from patients with posterior uveitis were tested by both multiplex and monoplex PCR. RESULTS: Fewer than 10 genomes of VZV and fewer than 100 genomes of HSV, CMV, and T gondii could be detected using the new primer sets. When used in multiplex, the assay lost less than 1 log of sensitivity. Monoplex PCR detected pathogen DNA in 18 of 21 patient samples; multiplex PCR detected pathogen DNA in 15 of the 18 samples positive by monoplex PCR. None of 10 negative control samples were positive for pathogen DNA. CONCLUSIONS: Multiplex PCR has adequate sensitivity to simultaneously screen a substantial differential diagnosis for posterior uveitis in a single reaction, without loss of specificity. This assay may reduce the time and cost involved in PCR-based molecular diagnostics of infectious pathogens. CLINICAL RELEVANCE: Mutiplex PCR may allow rapid diagnosis of infectious posterior uveitis.

Serologic and polymerase chain reaction analysis of intraocular fluids in the diagnosis of infectious uveitis.

PURPOSE: Infectious uveitis entities are usually rapidly progressive blinding diseases that can be prevented by prompt administration of specific antimicrobial therapy. With the aim of improving early diagnosis in patients with infectious uveitis, intraocular fluid samples from patients with sight-threatening posterior uveitis were investigated to determine the causative agent. METHODS: Thirty-eight patients with acquired immunodeficiency syndrome (AIDS) and retinitis, eight immunosuppressed patients with retinitis, 16 immunocompetent patients with acute retinal necrosis, and 22 immunocompetent patients with toxoplasmic retinochoroiditis were analyzed by polymerase chain reaction for the presence of herpesviruses and Toxoplasma gondii DNA and for local antibody production against these microorganisms. RESULTS: In patients with AIDS and retinitis, polymerase chain reaction was positive for cytomegalovirus DNA in 21 (91%) of the 23 ocular fluid samples obtained during active cytomegalovirus retinitis, whereas local antibody production analysis was negative in all cases. In acute retinal necrosis, varicella-zoster virus or herpes simplex virus could be established as the inciting agent in 81% of the cases, using the combination of both techniques. Polymerase chain reaction was positive in all samples obtained within two weeks after the onset of disease. Toxoplasma gondii DNA was detected in 4 of 13 samples (31%) from immuno-competent patients with active toxoplasmic retinochoroiditis; in each case, local antibody production was also detected. In contrast, no local antibody production was observed in two of three samples from transplant recipients that were positive for T. gondii DNA. All the control samples tested were negative for the above-mentioned tests. CONCLUSIONS: In patients with AIDS, polymerase chain reaction analysis is preferable above local antibody production in detecting the inciting agent of retinitis. In other cases, the combination of both techniques can make a valuable contribution to the diagnosis.

Treatment of ocular toxocariasis with albendazole.

The purpose of this study was to evaluate the efficacy of combined albendazole and steroid treatment for uveitis caused by Toxocara canis in immunocompetent patients. Five patients (7 eyes) with ocular larva migrans syndrome (OLM) were used in this study. Toxocariasis was suspected based on clinical manifestations and confirmed by anti-toxocara IgG and Western blot analysis. Systemic albendazole (adults: 800 mg b.i.d.; children: 400 mg b.i.d.) was given in conjunction with steroids. Visual acuity before and after therapy, inflammatory response, side effects and toxicity were evaluated. Treatment resulted in an improved visual acuity in all patients. Mean initial Snellen visual acuity was 20/40, and mean final acuity was 20/20. There were no recurrences of uveitis throughout the observation period (average: 13.8 months; range: 3 days to 24 months). These findings suggest that albendazole, in combination with systemic steroids, is a useful regimen to treat ocular larva migrans syndrome.

[Utility of ultrasonography in toxoplasmic uveitis]. / Utilidad de la ecografía en las uveítis por toxoplasmosis.

PURPOSE: To analyze the main indications and the most common ultrasonographic features observed in uveitis due to toxoplasmosis. MATERIAL AND METHODS: We carried out a retrospective, observational and descriptive study performed in 97 exams corresponding to 89 patients with uveitis during 7 consecutive years (1994-2000) using B-ultrasonography evaluation. RESULTS: The main ultrasonographic indication in toxoplasmosis was vitreous opacity. We observed that the most frequent findings were: a) intravitreous punctiform echoes, b) thickening of posterior hyaloid, c) partial or total posterior vitreous detachment and d) focal retinochoroidal thickening. This last finding should be highlighted due to its significant correlation (p<0.01) with toxoplasmosis. CONCLUSIONS: Our results suggest that ultrasonography plays an important role in the diagnosis and clinical follow-up of toxoplasmic uveitis.

Prevalence of Toxoplasma gondii and Toxocara canis among patients with uveitis.

PURPOSE: To investigate the prevalence of Toxoplasma gondii and Toxocara canis in patients with uveitis. METHOD: Patients with uveitis were examined. Serum antibodies to T. gondii and T. canis were tested by using enzyme-linked immunosorbent assay (ELISA). Polymerase chain reaction (PCR) was done using blood and aqueous humor (AH). RESULTS: 98 patients were enrolled. Mean age was 43.5 ± 13.2 years. Six patients were seropositive for T. gondii with the following pattern-anterior uveitis: 1; posterior uveitis with retinitis: 2; pan uveitis: 2. One patient had a positive result of PCR for T.gondii in AH, who showed pan uveitis. 23 patients were positive to serum IgG for T. canis with the following clinical manifestation-granuloma: 6; pigmented scar: 3; virtrits: 6-but none were PCR positive. CONCLUSION: T.gondii and T.canis are still one of the important causes of uveitis. Ocular toxocariasis is not an uncommon cause of uveitis even in adult.

Infectious causes of posterior uveitis.

The differential diagnosis of posterior infectious uveitis is broad. There are, however, a few common infectious causes of posterior uveitis that should always be considered. The more common infectious causes of posterior uveitis include syphilis, toxoplasmosis, tuberculosis, endogenous endophthalmitis, and viral causes (including herpes simplex virus, herpes zoster virus, and cytomegalovirus). The clinical features, diagnostic tools, and treatment options for each of these are reviewed in this article.