Ocular Involvement Following Postnatally Acquired Toxoplasma gondii Infection in Southern Brazil: A 28-Year Experience.

PURPOSE: To determine the incidence of, and risk factors for, ocular involvement among people known to have postnatally acquired Toxoplasma gondii infection in a region of southern Brazil where there is a high prevalence of endemic disease. DESIGN: Retrospective longitudinal cohort study. METHODS: Records of 302 patients with serologic evidence of recent T gondii infection (a positive anti-T gondii IgM antibody test) from Erechim, Rio Grande do Sul state, Brazil (1974-2002) were analyzed. The incidence of ocular involvement was calculated in terms of person-years (PY) of follow-up. Risk factors for ocular involvement were analyzed using log-rank and Fisher exact tests. RESULTS: At initial ocular examination (baseline), 30 patients (9.9%) had intraocular inflammation only (anterior chamber cells and flare, vitreous inflammatory reactions, retinal whitening), without clinically apparent necrotizing retinochoroiditis. At baseline, men were more likely to have ocular involvement (P = .043) and antiparasitic treatment was associated with less ocular involvement (P = .015). Follow-up examinations were performed on 255 patients (median follow-up, 13.7 months [range 0.4-261.9 months]). Among those without ocular involvement at baseline, the incidence of necrotizing retinochoroiditis was 6.4/100 PY. Patients >40 years of age at first IgM test had a greater risk of incident necrotizing retinochoroiditis (hazard ratio = 4.47, 95% CI = 1.67-11.93, P = .003) than younger patients. The incidence of recurrent necrotizing retinochoroiditis was 10.5/100 PY. CONCLUSION: Isolated intraocular inflammatory reactions can be an initial manifestation of T gondii infection, with necrotizing retinochoroiditis occurring months or years later. Male sex and older age are risk factors for toxoplasmic retinochoroiditis. Antitoxoplasmic treatment may protect against early ocular involvement.

Ocular Involvement Following an Epidemic of Toxoplasma gondii Infection in Santa Isabel do Ivaí, Brazil.

PURPOSE: To investigate ocular involvement (prevalence, incidence, lesion characteristics) following postnatally acquired infection with an "atypical" genotype of Toxoplasma gondii during a well-characterized 2001 outbreak in Santa Isabel do Ivaí, Brazil, attributed to a contaminated municipal reservoir. DESIGN: Prospective longitudinal cohort study. METHODS: We performed ophthalmic examinations on 290 of 454 individuals with serologic evidence of T gondii infection during the epidemic (positive IgM antibody tests). Prevalence of ophthalmic findings (intraocular inflammatory reactions [including transient, isolated retinal whitening without clinically apparent retinal necrosis] and necrotizing retinochoroiditis) at initial examination (baseline) and incidence of new findings during 10.5 months of follow-up were calculated. Cumulative risks of ophthalmic events were determined (Kaplan-Meier technique). RESULTS: Ocular involvement was present in 33 of 288 IgM+ individuals (11.5%) at baseline, including 17 with focal retinal whitening only and 13 with necrotizing retinochoroiditis. Incidence of new ocular involvement was estimated to be 1.73 events per 100 person-months (PM); cumulative risk at 10.5 months was 30.1%. Incident necrotizing retinochoroiditis was more common among those with focal retinal whitening at baseline (6.7/100 PM) than among those with no ocular involvement at baseline (1.11/100 PM; hazard ratio 6.07 [1.94-19.01]; P < .0001). CONCLUSIONS: Waterborne infection with an atypical genotype of T gondii is associated with substantial risk of ocular involvement. Lesions may continue to develop during the first year after infection. The increased risk of late necrotizing retinochoroiditis associated with isolated focal retinal whitening at presentation suggests the early presence of parasites in the retina, despite initial lack of observable retinal necrosis.

Toxoplasma gondii in the peripheral blood of patients with acute and chronic toxoplasmosis.

BACKGROUND AND AIMS: Toxoplasmic retinochoroiditis may recur months or years after the primary infection. Rupture of dormant cysts in the retina is the accepted hypothesis to explain recurrence. Here, the authors present evidence supporting the presence of Toxoplasma gondii in the peripheral blood of immunocompetent patients. METHODS: Direct observation by light microscopy and by immunofluorescence assay was performed, and results were confirmed by PCR amplification of parasite DNA. RESULTS: The authors studied 20 patients from Erechim, Brazil, including acute infected patients, patients with recurrent active toxoplasmic retinochoroiditis, patients with old toxoplasmic retinal scars, and patients with circulating IgG antibodies against T gondii and absence of ocular lesions. Blood samples were analysed, and T gondii was found in the blood of acutely and chronically infected patients regardless of toxoplasmic retinochoroiditis. CONCLUSIONS: The results indicate that the parasite may circulate in the blood of immunocompetent individuals and that parasitaemia could be associated with the reactivation of the ocular disease.

Identification of an atypical strain of toxoplasma gondii as the cause of a waterborne outbreak of toxoplasmosis in Santa Isabel do Ivai, Brazil.

Multilocus DNA sequencing has identified a nonarchetypal strain of Toxoplasma gondii as the causal agent of a waterborne outbreak in Brazil in 2001. The strain, isolated from a water supply epidemiologically linked to the outbreak, was virulent to mice, and it has previously been identified as BrI. Using a serologic assay that detects strain-specific antibodies, we found that 13 (65%) of 20 individuals who were immunoglobulin (Ig) M positive during the outbreak possessed the same serotype as mice infected with the purported epidemic strain. The remaining 7 individuals, plus additional IgM-negative, IgG-positive individuals, possessed 1 of 4 novel serotypes, the most common of which matched the serotype of mice infected with strains isolated from chickens foraging near the outbreak site. The latter strains likely reflect the genetic diversity of T. gondii circulating in highly endemic regions of Brazil. The serotyping assay proved a useful tool for identification of specific individuals infected with the outbreak agent.

Ocular toxoplasmosis: the influence of patient age.

The influence of patient age on various features of ocular toxoplasmosis has been a subject of study for many years. The age at which Toxoplasma gondii infection occurs in different populations is related to socioeconomic factors and studies suggest that ocular toxoplasmosis is a more severe disease at the extremes of age. The prevalence of ocular involvement is markedly different between individuals with congenital and those with post-natally acquired infections. Even among those with post-natally acquired infections, age influences the risk and timing of ocular involvement. The severity of toxoplasmic retinochoroiditis (in terms of lesion size, location and associated inflammation) is also affected by patient age at the time of initial infection or recurrence. The risk of recurrent toxoplasmic retinochoroiditis is influenced by age at the time of initial infection and age at most recent episode of active disease. Understanding of relationships between ocular toxoplasmosis and patient age is incomplete; evidence has often been indirect and in some cases conflicting. The influence of patient age on ocular toxoplasmosis should be studied in a systematic manner to provide a better understanding of disease mechanisms and to provide clinical information that can used to establish better strategies for disease treatment and prevention.

Ocular toxoplasmosis: the influence of patient age

The influence of patient age on various features of ocular toxoplasmosis has been a subject of study for many years. The age at which Toxoplasma gondii infection occurs in different populations is related to socioeconomic factors and studies suggest that ocular toxoplasmosis is a more severe disease at the extremes of age. The prevalence of ocular involvement is markedly different between individuals with congenital and those with post-natally acquired infections. Even among those with post-natally acquired infections, age influences the risk and timing of ocular involvement. The severity of toxoplasmic retinochoroiditis (in terms of lesion size, location and associated inflammation) is also affected by patient age at the time of initial infection or recurrence. The risk of recurrent toxoplasmic retinochoroiditis is influenced by age at the time of initial infection and age at most recent episode of active disease. Understanding of relationships between ocular toxoplasmosis and patient age is incomplete; evidence has often been indirect and in some cases conflicting. The influence of patient age on ocular toxoplasmosis should be studied in a systematic manner to provide a better understanding of disease mechanisms and to provide clinical information that can used to establish better strategies for disease treatment and prevention.

Intraocular inflammation associated with ocular toxoplasmosis: relationships at initial examination.

PURPOSE: To describe characteristics of intraocular inflammation in eyes with active ocular toxoplasmosis and to identify relationships between signs of inflammation, complications (including elevated intraocular pressure [IOP]), other disease features, and host characteristics. DESIGN: Multicenter, retrospective, cross-sectional study. METHODS: We reviewed the medical records of 210 patients with toxoplasmic retinochoroiditis at seven international sites (North America, South America, and Europe) for information from the first examination at each site during which patients had active retinal lesions. Signs of inflammation included anterior chamber (AC) cells and flare and vitreous humor cells and haze. Retinal lesion characteristics included size (< or =1 disc area [DA] or >1 DA) and presence or absence of macular involvement. RESULTS: AC cells and flare were related to vitreous inflammatory reactions (P < or = .041). One or more signs of increased inflammation were related to the following factors: older patient age, larger retinal lesions, and extramacular location. In 30% of involved eyes, there was evidence of elevated IOP (despite use of glaucoma medications by some patients); other complications were uncommon. IOP of more than 21 mm Hg was associated with both increased AC cells and elevated flare (both P < or = .001) and with macular involvement (P = .009). Inflammation seemed to be more severe among patients in Brazil than among those at other sites. CONCLUSIONS: There is substantial variation between patients in the severity of intraocular inflammation associated with ocular toxoplasmosis, attributable to multiple host- and disease-related factors. Results suggest that disease characteristics also vary in different areas of the world. Elevated IOP at initial examination reflects the severity of inflammation.

Recently acquired Toxoplasma gondii infection, Brazil.

The city of Erechim, Brazil, has a 17% prevalence of ocular toxoplasmosis, and type 1 Toxoplasma gondii predominates. To examine risk factors for acute T. gondii infection in this area, we administered a questionnaire to recently infected persons (n = 131) and seronegative controls (n = 110). Eating undercooked meat; having a garden; working in the garden or yard more than once per week; eating rare meat; eating cured, dried, or smoked meat; eating frozen lamb; and being male increased risk for T. gondii infection in univariate analysis. Risk factors independently associated with acute T. gondii infection in multivariate analysis were working in the garden (odds ratio [OR] 2.35, 95% confidence interval [CI] 1.27-4.33) and eating frozen lamb (OR 2.06, 95% CI 1.15-3.67). Among women (n = 86), having had children markedly increased the risk for T. gondii infection (OR 14.94, 95% CI 3.68-60.73).

Crotaline snake bite in the Ecuadorian Amazon: randomised double blind comparative trial of three South American polyspecific antivenoms.

OBJECTIVE: To compare the efficacy and safety of three polyspecific antivenoms for bites by pit vipers. DESIGN: Randomised double blind comparative trial of three antivenoms. SETTING: Shell, Pastaza, southeastern Ecuador. PARTICIPANTS: 210 patients with incoagulable blood were recruited from 221 consecutive patients admitted with snake bite between January 1997 and December 2001. INTERVENTION: One of three antivenoms manufactured in Brazil, Colombia, and Ecuador, chosen for their preclinical potency against Ecuadorian venoms. MAIN OUTCOME MEASURES: Permanent restoration of blood coagulability after 6 and 24 hours. RESULTS: The snakes responsible for the bites were identified in 187 cases: 109 patients (58%) were bitten by Bothrops atrox, 68 (36%) by B bilineatus, and 10 (5%) by B taeniatus, B brazili, or Lachesis muta. Eighty seven patients (41%) received Colombian antivenom, 82 (39%) received Brazilian antivenom, but only 41 (20%) received Ecuadorian antivenom because the supply was exhausted. Two patients died, and 10 developed local necrosis. All antivenoms achieved the primary end point of permanently restoring blood coagulability by 6 or 24 hours after the start of treatment in > 40% of patients. Colombian antivenom, however, was the most effective after initial doses of 20 ml (two vials), < 70 ml, and any initial dose at both 6 and 24 hours. An initial dose of 20 ml of Colombian antivenom permanently restored blood coagulability in 64% (46/72) of patients after 6 hours (P = 0.054 compared with the other two antivenoms) and an initial dose of < 70 ml was effective at 6 hours (65%, P = 0.045) and 24 hours (99%, P = 0.06). Early anaphylactoid reactions were common (53%, 73%, and 19%, respectively, for Brazilian, Colombian, and Ecuadorian antivenoms, P < 0.0001) but only three reactions were severe and none was fatal. CONCLUSIONS: All three antivenoms can be recommended for the treatment of snakebites in this region, though the reactogenicity of Brazilian and Colombian antivenoms is a cause for concern.

The effect of long-term intermittent trimethoprim/sulfamethoxazole treatment on recurrences of toxoplasmic retinochoroiditis.

PURPOSE: To determine the effect of long-term intermittent trimethoprim/sulfamethoxazole treatment on recurrences of toxoplasmic retinochoroiditis. DESIGN: Prospective randomized open-labeled interventional clinical trial. METHODS: A total of 124 patients with a history of recurrent toxoplasmic retinochoroiditis were randomized to treatment with one tablet of trimethoprim (160 mg)/sulfamethoxazole (800 mg) (Bactrim F; Roche Pharmaceuticals, Rio de Janeiro, Brazil) every 3 days (61 patients) or to observation without treatment (63 patients) and were followed monthly for up to 20 consecutive months for clinical signs of disease recurrence. A recurrence was defined as a new focus of necrotizing retinochoroiditis with active inflammation either adjacent to or remote from preexisting retinochoroidal scars. RESULTS: Recurrences developed in four (6.6%) treated patients and in 15 (23.8%) controls (P =.01). Treatment was discontinued prematurely in four patients because of mild drug reactions. CONCLUSION: Long-term intermittent treatment with trimethoprim/sulfamethoxazole can reduce the rate of recurrent toxoplasmic retinochoroiditis.

Cytomegalovirus retinopathy: current concepts and therapeutic options / Cytomegalovirus

Retinopatia por citomegalovirus é a infecçäo mais comum em pacierntes com AIDS, e tem sido muito estudado em atençäo à qualidade de vida dos aidéticos. Grande progresso tem ocorrido sobre a retinopatia por citomegalovirus em relaçäo à década anterior. Esta revisäo cobrirá as opçöes de tratamento para esta doença e conceitos pertinentes que auxilia no planejamento de tomada de decisöes