Frequency of Toxoplasma gondii in the retina in eye banks in Brazil.

Ocular toxoplasmosis is the main cause of posterior uveitis worldwide frequently leading to vision loss. In Brazil, the seroprevalence of Toxoplasma gondii infection ranges from 50 to 80% depending of the region studied. The frequency of toxoplasmic retinal scar may reach 18% of the adults in the South of Brazil. Our goal was to determine the frequency of T. gondii DNA in retinas from eye banks from different regions in Brazil. A total of 162 eyes were obtained from eye banks in Manaus (n = 60), Sao Paulo (n = 60), Chapeco (n = 26), and Joinville (n = 16). The retinas were macroscopically analyzed and collected for DNA extraction. Real-time PCR (qPCR) was performed using the T. gondii B1 marker. By qPCR, a higher frequency of T. gondii DNA in the retinas from the eye bank of Joinville (25%) was found when compared to Manaus (5%). The retinas from Sao Paulo and Chapeco were qPCR negative. Clinical examination determined the retina lesions to be compatible with toxoplasmosis in the following frequencies: Joinville (62.5%), Manaus (10%), Sao Paulo (6.7%), and Chapeco (15.4%).

OCTA Imaging of Choroidal Neovascular Membrane Secondary to Toxoplasma Retinochoroiditis.

Two patients (a 37-year-old man and a 28-year-old woman) who had choroidal neovascular membrane (CNVM) secondary to inactive toxoplasma retinochoroiditis scarring were evaluated. Multimodal imaging including fluorescein angiography, optical coherence tomography (OCT), and OCT angiography (OCTA) was used. CNVM secondary to inactive toxoplasma retinochoroiditis scarring was detected. Representative images of CNVM were demonstrated in the outer retinal layer and choriocapillary layer on OCTA. OCTA, a relatively new technique, is useful in the diagnosis of the CNVMs secondary to retinochoroiditis. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:509-511.].

Acquired retinochoroiditis in hamsters inoculated with ME 49 strain Toxoplasma.

PURPOSE: These studies were undertaken to establish an animal model for use in studies of ocular toxoplasmosis. An animal model is needed to examine the development, progression, and resolution of ocular Toxoplasma infections and to study the effects on the disease of currently used and experimental therapies. METHODS: Cysts of the ME 49 strain of Toxoplasma gondii were injected intraperitoneally into each of 60 golden hamsters. The hamsters' eyes were examined before inoculation and at intervals after inoculation, and fundus photographs were taken. Histologic sections were analyzed and photographed to document the ocular effects of the infection. RESULTS: Retinochoroiditis was found in both eyes of all hamsters within 2 to 3 weeks of inoculation. The disease resolved spontaneously without treatment and was quiescent in most cases at 12 weeks after inoculation. The animals remained in good general health, and those tested had high antibody titers to Toxoplasma (1:256 to 1:32,000) at 6 months after the infection. The discovery of cysts and lesions in the retina confirmed the diagnosis. CONCLUSIONS: Although the lesions were not identical to those of human disease, this animal model of ocular toxoplasmosis offers several advantages: reproducibility, short incubation time, spontaneous resolution without treatment, consistent production of cysts, and ease of inoculation intraperitoneally without intraocular injection.

Toxoplasma antibodies and retinochoroiditis in the Marshall Islands and their association with exposure to radioactive fallout.

Nearly universal serologic evidence of Toxoplasma gondii infection was found to have occurred by adulthood in 517 Marshallese tested in 1981-1982. The prevalence and incidence of retinal lesions compatible with toxoplasmosis were 3.9% and 273 cases/year/100,000 seropositive persons, respectively, thus indicating a significant public health problem. Seronegativity was significantly more common in a subgroup of Marshallese that had received 110-190 rads of total-body gamma radiation as a consequence of accidental exposure to radioactive fallout in 1954. Despite this finding there was no evidence of an increase in clinically significant lesions in exposed persons.

Toxoplasmic retinochoroiditis: new insights provided by indocyanine green angiography.

PURPOSE: To analyze features of indocyanine green angiography associated with recurrent toxoplasmic retinochoroiditis. METHODS: Indocyanine green angiography was performed according to a standard protocol and correlated with clinical signs and fluorescein angiography in 12 eyes of 12 consecutive patients with recurrent toxoplasmic retinochoroiditis. RESULTS: In 10 of 12 eyes with recurrent toxoplasmic retinochoroiditis, indocyanine green angiography showed multiple satellite dark dots not seen on fluorescein angiography or clinical examination of the fundus. CONCLUSION: Indocyanine green angiography shows that recurrent toxoplasmic retinochoroiditis is more widespread than clinically visible lesions indicate. Indocyanine green angiography is useful in assessing the extent of involvement of recurrent toxoplasmic retinochoroiditis and the evolution of lesions and might also provide insights into the pathophysiology of the disease.

Intraocular inflammatory reactions without focal necrotizing retinochoroiditis in patients with acquired systemic toxoplasmosis.

PURPOSE: To describe the occurrence of intraocular inflammatory reactions as the sole ophthalmic manifestation of acquired systemic toxoplasmosis. METHODS: Review of medical records for 10 patients with uveitis and evidence of recent Toxoplasma gondii infection. RESULTS: Patient ages ranged from 3 to 51 years. Ocular symptoms were present in each of eight adult patients. Inflammation was unilateral in nine patients; it manifested as vitreous humor cells and haze (10 patients), anterior chamber cells (seven patients), and retinal vasculitis (seven patients). No patient had necrotizing retinochoroiditis upon initial examination. Inflammation resolved in each of nine patients who had follow-up examinations. Foci of retinitis or inactive retinochoroidal scars were seen in four of these nine patients during follow-up examinations, at intervals of 2.0 weeks to 2.5 years after initial examination. CONCLUSIONS: Retinal vasculitis and associated inflammatory reactions may be the only ophthalmic disorder during the early stages of a newly acquired T. gondii infection. Later development of retinitis or scars consistent with toxoplasmic retinochoroiditis in the same eyes suggests that the initial, isolated inflammation may be caused by the presence of parasites in retinal tissue. These cases may have implications for understanding the original source of retinal infection in patients who have recurrent toxoplasmic retinochoroiditis and for treatment of newly acquired T gondii infection.

Schistosomotic choroiditis. II. Report of first case.

The first case of granulomatous choroiditis produced by Schistosoma mansoni with histological confirmation is reported. The patient had the hepatosplenic and cardiopulmonary forms of the disease and presented with cerebral schistosomiasis. The funduscopic aspects of the lesion and the possible pathways taken by the parasite to reach the choroid are discussed.

Is reactivation of toxoplasmic retinochoroiditis associated to increased annual rainfall?

BACKGROUND: Reactivation of toxoplasmic retinochoroiditis is the most frequent form of uveitis in Misiones, Argentina. Fluctuations in the number of patients consulting with this type of uveitis were detected during the last decade. Since the province was consecutively exposed to rainy and dry periods over the last years, we decided to explore whether a relationship between reactivation of toxoplasmic retinochoroiditis and rain might be established according to the data registered during the 2004-2010 period. RESULTS: The frequency of toxoplasmic reactivation episodes increases when precipitation increases (mostly in second and fourth trimesters of each year). Analysis of the independent variables demonstrates that precipitation is a significant predictor of the frequency of reactivation episodes. Although registered toxoplasmic reactivations were more frequent during the third trimester of the year, the association between the third trimester and the reactivation episodes did not reach statistical significance. CONCLUSION: Prolonged and intense rainfall periods were significantly associated with the reactivation of toxoplasmic retinochoroiditis. Changes promoted by this climatic condition on both the parasite survival in the soil as well as a putative effect on the host immune response due to other comorbidities are discussed.

Fulminant toxoplasmic retinochoroiditis following intravitreal triamcinolone administration.

We report two cases of fulminant toxoplasmic retinochoroiditis following intravitreal triamcinolone acetonide (IVTA) administration. Case 1: A 42-year-old female received IVTA for presumed non-infectious panuveitis. Within 2 months, she developed diffuse macular retinochoroiditis with optic disc edema. Upon starting anti-toxoplasmic therapy (ATT), her intraocular inflammation resolved with catastrophic damage to the disc and macula. Case 2: A 30-year-old male received IVTA for presumed reactivation of previously scarred toxoplasmic retinochoroiditis. Despite simultaneous ATT, within 6 weeks, he developed extensive, multifocal macular retinochoroiditis. He continued to require ATT for 18 months and later underwent vitrectomy with silicone oil placement for severe epiretinal proliferation. Aqueous tap polymerase chain reactions were found positive for Toxoplasma gondii in both cases. In conclusion, IVTA administration can lead to fulminant toxoplasmic retinochoroiditis even when used with appropriate ATT. Extreme caution should be exercised while administering depot corticosteroids in eyes with panuveitis of unknown origin.

Clinical manifestations of ocular toxoplasmosis.

Clinical manifestations of ocular toxoplasmosis are reviewed. Findings of congenital and acute acquired ocular toxoplasmosis include retinal scars, white-appearing lesions in the active phase often associated with vitritis. Complications can include fibrous bands, secondary serous or rhegmatogenous retinal detachments, optic neuritis and neuropathy, cataracts, increased intraocular pressure during active infection, and choroidal neovascular membranes. Recurrences in untreated congenital toxoplasmosis occur in teenage years. Manifestations at birth are less severe, and recurrences are fewer in those who were treated promptly early in the course of their disease in utero and in the first year of life. Severe retinal involvement is common at diagnosis of symptomatic congenital toxoplasmosis in the United States and Brazil. Acute acquired infections also may be complicated by toxoplasmic retinochoroiditis, with recurrences most common close to the time of acquisition. Suppressive treatment can reduce recurrent disease.

Combination photodynamic therapy and bevacizumab for choroidal neovascularization associated with toxoplasmosis.

A 14-year-old girl presenting with visual loss in both eyes was diagnosed to have healed toxoplasma retinochoroiditis in the right eye with active choroidal neovascularization (CNV) secondary to toxoplasmosis in the left. She underwent combination photodynamic therapy (PDT) and intravitreal bevacizumab as primary treatment. PDT was performed as per the 'Treatment of Age-related Macular Degeneration by Photodynamic therapy' study protocol and was followed by intravitreal bevacizumab after 2 days. CNV regressed at 8 weeks of follow-up and remained stable at 8 months of follow-up. The initial visual acuity improved from 20/120 to 20/30. Combination therapy with PDT and intravitreal bevacizumab appears to be effective in the treatment of CNV secondary to toxoplasma retinochoroiditis.

Too late prenatal diagnosis of fetal toxoplasmosis: a case report.

OBJECTIVE: We describe a case of severe fetal hydrocephalus due to toxoplasmosis which could not be diagnosed until late gestational age due to the lack of a serologic surveillance program during pregnancy; moreover, this case points to the usefulness of molecular biology tools in the diagnostic process. Abnormal ultrasound in the 2nd trimester was noticed and Toxoplasma gondii was demonstrated in amniotic fluid at the 28th week of gestation both by PCR and by mice inoculation. Fansidar and folinic acid were administered. The newborn suffered from progressive hydrocephalus, seizures, and pathological muscular tonus; ultrasound examination showed massive cerebral calcifications. Ophthalmologic examination revealed bilateral choroidoretinitis. Congenital toxoplasmosis was confirmed by the detection of anti- T. gondii IgM and IgA in the neonatal serum. CONCLUSION: The presented case is an example of severe fetal toxoplasmosis diagnosed and treated in utero.

Retinochoroiditis is induced by oral administration of Toxoplasma gondii cysts in the hamster model.

Administration of Toxoplasma cysts by intraperitoneal innoculation in the Syrian Golden Hamster provides a reproducible animal model of acquired Toxoplasmic retinochoroiditis and cysts are observed in the brain. However, toxoplasmosis is frequently acquired by oral ingestion of contaminated foodstuffs and it is recognised that the route by which disease is acquired may influence its pathogenesis and clinical expression. This study aimed to determine whether retinochorioiditis and cysts in the brain develop after oral ingestion in the Syrian Golden Hamster model as this is the route of induction akin to that in man and may therefore be more relevant in the study of disease pathogenesis. All animals developed disease by 4 weeks. Ocular and cerebral inflammation was confirmed by histology at 16 weeks and this was milder than in the original model.

Atypical presentations of ocular toxoplasmosis.

The diagnosis of ocular toxoplasmosis is based most often on the presence of characteristic clinical findings, which include focal retinochoroiditis, an adjacent or nearby retinochoroidal scar, and moderate to severe vitreous inflammation. However, a variety of less common, "atypical" presentations may be unfamiliar to clinicians, delaying both diagnosis and treatment. Patients who are immunocompromised or elderly may, for example, present with large, multiple and/or bilateral lesions. Other unusual manifestations include punctate outer retinal toxoplasmosis, retinal vasculitis, retinal vascular occlusions, rhegmatogenous and serous retinal detachments, a unilateral pigmentary retinopathy mimicking retinitis pigmentosa, neuroretinitis and other forms of optic neuropathy, and scleritis. Although in the past most cases of ocular toxoplasmosis were considered to result from reactivation of a congenital infection, it is now believed that postnatally acquired infection accounts for many cases of this disease. With appropriate use of antiparasitic therapy, the visual prognosis for patients with both typical and atypical forms of ocular toxoplasmosis may be good.

Infectious multifocal choroiditis in patients with acquired immune deficiency syndrome.

PURPOSE: The purposes of this study are to determine the incidence of infectious opportunistic choroiditis in patients with the acquired immune deficiency syndrome (AIDS), to study the association of these choroidal infections with systemic dissemination, and to investigate the life expectancy and cause of death in patients with infectious opportunistic choroiditis. METHODS: A total of 470 eyes of 235 consecutive autopsies of patients with AIDS were examined by histopathologic methods. The clinical charts and autopsy reports of these patients were subsequently reviewed for presence of systemic dissemination of various infectious agents. RESULTS: Of the 235 patients, 18 were found to have infectious choroiditis. The etiologic agents found were: Cryptococcus neoformans, Pneumocystis carinii, Mycobacterium tuberculosis, Histoplasma capsulatum, Candida, Aspergillus fumigatus, Toxoplasma gondii, and Mycobacterium avium-intracellulare. In 15 of these 18 patients, the cause of death was considered to be due to systemic dissemination of the organism causing the choroiditis. Only 4 of the 18 cases of infectious choroiditis were diagnosed during life, and the survival time of these patients after diagnosis was only 25 days. Five of the 18 patients also were found to have cytomegalovirus (CMV) infection of the retina. CONCLUSION: Multifocal choroiditis due to endogenous infectious emboli in patients with AIDS reflects systemic dissemination and localization of infectious agents predominantly in the choriocapillaris. Early diagnosis and treatment are imperative and may be life-saving.

Toxoplasma gondii retinochoroiditis and optic neuritis in acquired immune deficiency syndrome. Report of a case.

A 29-year-old man with acquired immune deficiency syndrome (AIDS) was found to have a retinochoroiditis and optic neuritis of his left eye. Results of fundus examination showed inflammatory and hemorrhagic retinal lesions consistent with retinitis due to cytomegalovirus infection. A computed tomographic (CT) scan demonstrated enlargement of the optic nerve. The eye was enucleated and results of histopathologic examination showed retinal necrosis with underlying choroiditis and an optic neuritis. Numerous encysted Toxoplasma gondii organisms were present in the retina and tachyzoites were present in the optic nerve. To the authors' knowledge this is the second histologically documented case of Toxoplasma optic neuritis in a patient with AIDS.