RESUMEN

Major outer membrane protein sequences, determined from Chlamydia-positive eye swab samples collected in 2 Egyptian villages, were used to analyze the epidemiology of trachoma in an endemic setting. Samples were collected during the 1999 Azithromycin in Control of Trachoma trial, in which residents of villages were mass treated with either oral azithromycin or topical tetracycline and were followed up for nearly 2 years. Three genovar families (A, Ba, and C) and 12 genovars were detected, with 2 genovars (A1 and Ba1) comprising almost 75% of the samples. The presence of >1 genovar within households was common, with > or =24% of households having >1 genovar. Evidence consistent with reinfection and persistence as mechanisms of communitywide continued presence of trachoma was provided by data for individuals infected with rare genovars.

Asunto(s)

Asunto(s)

RESUMEN

BACKGROUND: Trachoma is the leading cause of preventable blindness. Programmes to prevent blindness due to trachoma are based on community-wide treatment with topical tetracycline. We assessed the potential of community-wide azithromycin treatment for trachoma control. METHODS: Pairs of villages in trachoma endemic areas of Egypt, The Gambia, and Tanzania were matched on trachoma rates in 1-10-year-old children. Villages were randomly assigned community-wide oral azithromycin treatment (three doses with intervals of 1 week) or treatment with 1% topical tetracycline (once daily for 6 weeks). Clinical examinations were done at baseline, 2-4.5 months, and 12-14 months after treatment. Chlamydia trachomatitis was identified by ligase chain reaction (LCR). Analyses were by intention to treat. Univariate comparisons and multivariate analyses were used to compare outcomes. FINDINGS: LCR positivity was correlated with clinical severity, but about 30% of Egyptian and Gambian villagers with no active disease were LCR positive. Village-wide LCR positivity ranged from 16.5% (Tanzania) to 43.6% (Egypt). Treatment compliance was over 90% except in the tetracycline treatment village in Egypt. Of the participants initially LCR positive, 866 (95%) of 924 who received at least one azithromycin dose and 482 (82%) of 587 who received 28 days or more topical tetracycline, were negative at follow-up. At 1 year, village-wide LCR positivity rates were substantially lower than at baseline with both treatments; the decreases were greater with azithromycin than with tetracycline (93% vs 77% in Egypt, 78 vs 66% in The Gambia, 64 vs 55% in Tanzania). Similarly, greater reduction in clinical activity occurred after azithromycin. In multivariate analyses, factors associated with being LCR positive at 1 year were: not receiving azithromycin; age under 10 years; and LCR positivity at baseline. INTERPRETATION: Community-wide treatment with oral azithromycin markedly reduces C. trachomatis infection and clinical trachoma in endemic areas and may be an important approach to control of trachoma.

Asunto(s)

RESUMEN

September 15, 1997 marked the golden anniversary of the Francis I. Proctor Foundation, which was established in affiliation with the University of California in San Francisco. Over 50 years, 182 fellows from 27 countries have been trained in programs focusing on the study of infectious and inflammatory eye disease, and the prevention of blindness worldwide. Many of the people and events that have contributed to the success of the Proctor Foundation are presented in this brief essay.

Asunto(s)

RESUMEN

Trachoma, an infectious keratoconjunctivitis caused by Chlamydia trachomatis, is a leading cause of preventable blindness in developing countries. In this study we compared oral azithromycin with oxytetracycline/polymyxin eye ointment (once daily for 5 days every 4 weeks; total of six treatment cycles) for the treatment of active endemic trachoma in 168 rural Egyptian children. A suspension of azithromycin was administered to children as a dose of 20 mg/kg by one of three schedules: a single dose, one dose a week for 3 weeks, and one dose every 4 weeks for a total of six doses. The children's clinical status and chlamydial infection rates were evaluated for 1 year. The clinical cure rates were 35% 2 months after initial treatment, 16% at 8 months (during the annual autumn epidemic of purulent conjunctivitis), and 47% at 1 year. The pretreatment chlamydial infection rate of 33% (determined by direct immunofluorescence) decreased to 5% at 2 months and was 9% at 12 months. There were no significant clinical or laboratory differences among the four treatment groups. Thus, 1-6 doses of azithromycin were equivalent to 30 days of topical oxytetracycline/polymyxin ointment and may offer an effective alternative means of controlling endemic trachoma.

Asunto(s)

RESUMEN

AIMS: Possible risk factors were evaluated for herpes simplex virus (HSV) epithelial keratitis in patients with stromal keratouveitis. METHODS: The study population included 260 patients who had active stromal keratitis and/or iridocyclitis without epithelial disease and who were enrolled in one of three clinical trials of the Herpetic Eye Disease Study. Study treatment involved a 10 week course of topical placebo, topical prednisolone phosphate, or topical prednisolone phosphate with oral acyclovir. All groups received topical trifluridine four times daily for 3 weeks then twice daily for another 7 weeks. Patients were examined for HSV epithelial keratitis for 16 weeks. RESULTS: Dendritic or geographic epithelial keratitis occurred in 12 (4.6%) study patients. Adverse effects attributable to trifluridine prophylaxis were acute allergic blepharoconjunctivitis in 10 (3.8%) study patients and corneal epithelial erosions in 11 (4.2%) study patients. No significant difference in the occurrence of HSV epithelial keratitis was found among the study treatment groups: one (2.0%) of 49 topical placebo treated patients, nine (6.5%) of 138 patients treated with topical corticosteroids without acyclovir, and two (2.7%) of 73 patients treated with topical corticosteroids and oral acyclovir. Univariate exponential models suggested that patients with a history of previous HSV epithelial keratitis and non-white patients were more likely to develop HSV epithelial keratitis during treatment of stromal keratouveitis. CONCLUSION: Individuals with prior HSV epithelial keratitis and certain ethnic groups may have a higher rate of recurrent epithelial keratitis during the acute treatment of HSV stromal keratouveitis.

Asunto(s)

Asunto(s)

RESUMEN

A healthy female bird fancier developed progressive follicular keratoconjunctivitis despite topical treatment with antibiotics and steroids. Although bacterial, viral, and chlamydial cultures were negative, direct fluorescent antibody staining of conjunctival scrapings revealed chlamydial lipopolysaccharide; however, this procedure failed to detect the major outer membrane protein (MOMP) of Chlamydia trachomatis. The polymerase chain reaction (PCR) used with species-specific primers to the MOMP gene detected DNA of Chlamydia psittaci. Genotype analysis of the infecting strain revealed a nucleotide homology of 96% with C. psittaci avian strain 6-BC. Serum IgG titers were measured at 1:512 by microimmunofluorescence at 6 weeks, and they remained elevated for 3 months. A 10-week course of treatment with doxycycline was required for eradication of the infection. This case illustrates the importance of PCR/genotyping for direct detection and typing of Chlamydia species when chlamydial infections are suspected. To our knowledge, this is the first report of a naturally occurring ocular infection due to an avian strain of C. psittaci.

Asunto(s)

RESUMEN

PURPOSE: To evaluate the efficacy of oral acyclovir in treating stromal keratitis caused by herpes simplex virus (HSV) in patients receiving concomitant topical corticosteroids and trifluridine. METHODS: The authors performed a randomized, double-masked, placebo-controlled, multicenter trial in 104 patients with HSV stromal keratitis without accompanying HSV epithelial keratitis. Sample size was chosen so that a 5%, one-tailed test would have an 80% chance of detecting a doubling of the median time to treatment failure. Patients were randomized to receive a 10-week course of either oral acyclovir (400 mg 5 times daily, n = 51) or placebo (n = 53). All patients also received a standard regimen of topical prednisolone phosphate and trifluridine. Ophthalmologic examinations were performed weekly during the 10-week treatment period, every 2 weeks for an additional 6 weeks, and at 6 months after entry into the trial. RESULTS: The median time to treatment failure (defined as worsening or no improvement of stromal keratitis or an adverse event) was 84 days (95% confidence interval, 69-93 days) for the acyclovir group and 62 days (95% confidence interval, 57-90 days) for the placebo group. By 16 weeks, 38 patients (75%) in the acyclovir group and 39 patients (74%) in the placebo group had failed treatment. Also by that time, the keratitis had resolved with trial medications, and there was no subsequent worsening in nine patients (18%) in the acyclovir group and ten (19%) in the placebo group. None of these results were significantly different between the two groups. However, visual acuity improved over 6 months in significantly more patients in the acyclovir group than in the placebo group. CONCLUSION: There was no statistically or clinically significant beneficial effect of oral acyclovir in treating HSV stromal keratitis in patients receiving concomitant topical corticosteroids and trifluridine with regard to time to treatment failure, proportion of patients who failed treatment, proportion of patients whose keratitis resolved, time to resolution, or 6-month best-corrected visual acuity. Visual acuity improved over 6 months in more patients in the acyclovir group than in the placebo group.

Asunto(s)

RESUMEN

PURPOSE: To evaluate the efficacy of topical corticosteroids in treating herpes simplex stromal keratitis. METHODS: The authors performed a randomized, double-masked, placebo-controlled, multicenter clinical trial of 106 patients with active herpes simplex stromal keratitis who had not received any corticosteroids for at least 10 days before study enrollment. Patients were assigned to the placebo group (n = 49) or the steroid group (topical prednisolone phosphate; n = 57); both regimens were tapered over 10 weeks. Both groups received topical trifluridine. Visual acuity assessment and slit-lamp biomicroscopy were performed weekly for 10 weeks, every other week for an additional 6 weeks or until removal from the trial, and at 6 months after randomization. RESULTS: The time to treatment failure (defined by specific criteria as persistent or progressive stromal keratouveitis or an adverse event) was significantly longer in the steroid group compared with the placebo group. Compared with placebo, corticosteroid therapy reduced the risk of persistent or progressive stromal keratouveitis by 68%. The time from randomization to resolution of stromal keratitis and uveitis was significantly shorter in the steroid group compared with the placebo group even though both groups included patients who were removed from the study and treated with topical corticosteroids according to best medical judgment. Nineteen (33%) of the steroid-treated patients and 11 (22%) of the placebo-treated patients completed the 10 weeks of protocol therapy and had stable, noninflamed corneas after 16 weeks. At 6 months after randomization, no clinically or statistically significant differences in visual outcome or recurrent herpetic eye disease were identified between the steroid and placebo groups. CONCLUSIONS: The topical corticosteroid regimen used in this study was significantly better than placebo in reducing persistence or progression of stromal inflammation and in shortening the duration of herpes simplex stromal keratitis. Postponing steroids during careful observation for a few weeks delayed resolution of stromal keratitis but had no detrimental effect as assessed by visual outcome at 6 months.

Asunto(s)

Asunto(s)

RESUMEN

Through ophthalmological exams, structured interviews and participant observation, this study examines the experience of blindness in rural Egypt, and finds that villagers' subjective assessments of their vision differ substantially from ophthalmic measurements of their vision. Individuals with profound visual loss remain independent in their daily activities and contribute to their families' subsistence. While they may agree that they have "weak eyesight," they do not perceive themselves to be disabled. Stigmatizing attitudes that the blind are completely dependent and unable to fulfill their social roles further encourage those with decreased vision to deny the extent of their visual loss.

Asunto(s)

RESUMEN

The molecular evaluation of the chlamydial major outer membrane protein (MOMP) gene (omp1) can facilitate epidemiologic investigations of this pathogen. Genotyping of omp1 provides a more precise characterization of Chlamydia trachomatis than do current immunotyping techniques. Genetic omp1 variants of serovars that are responsible for ocular disease in Tunisia were identified. Archival conjunctival samples collected during 1972 and 1975 from trachoma patients in Douz were sequenced by automation along with additional B and Ba trachoma and genital isolates. Over 90% of the nucleotide changes resulted in an amino acid substitution. Different amino acid sequence changes in variable segments 1, 2, and 4 were found in the specimens collected in 1975 from those collected in 1972. Determination of omp1 genotypes responsible for trachoma will be useful for prospective, epidemiologic studies to identify chlamydial reservoirs within the host, evaluate transmission patterns, and determine the antigenic variation of MOMP for rational vaccine development.

Asunto(s)

RESUMEN

We studied three cases of Fuchs' superficial marginal keratitis, an uncommon condition that is characterized by intermittent, recurrent episodes of ocular irritation accompanied by marginal infiltrates and that is followed by progressive marginal superficial stromal thinning. Usually, it has an indolent course with spontaneous remission, and good visual acuity is preserved. In advanced cases, a pseudopterygium develops in the area of marginal thinning. The pseudopterygium encroaches onto the cornea over a period of years, but spares the central cornea. In two of our three cases, the degree of thinning beneath the pseudopterygium became marked. This led to corneal perforation during pseudopterygium excision in one case, and after blunt trauma in the other. These complications indicate the need for special precautions when caring for these patients.

Asunto(s)

RESUMEN

Several distinct populations of sensory neurons in the ophthalmic region of the mouse trigeminal ganglion have been identified by their reactivity to antibodies raised against substance P (SP), calcitonin gene-related peptide (CGRP), cell-surface glycoconjugates SSEA3 and LD2, and the plant lectin, Bandeiraea simplicifolia lectin 1, isolectin 4 (BSIL4). Thirty-six percent of the neurons in the ophthalmic portion of the mouse trigeminal ganglion express CGRP and 17%, SP. All neurons that express SP also express CGRP. Forty percent of the neurons in the ophthalmic region of the ganglion are recognized by monoclonal antisera to SSEA3, and 66% of this population also express the neuropeptides SP or CGRP. The neuronal population recognized by BSIL4 is identical to the population with the LD2 epitope. This population of cells (BSIL4/LD2) does not express the SSEA3 glycoconjugate and is largely nonpeptidergic. All four populations of sensory neurons (SP, CGRP, SSEA3, and LD2/BSIL4) can be infected by herpes simplex virus (HSV). However, the relative proportion of SSEA3- and LD2/BSIL4-labeled cells that were infected productively with HSV was much less than expected based on the relative size of the populations of these neurons in the ophthalmic region of the ganglion.

Asunto(s)

RESUMEN

We investigated the association between inflammatory trachoma in children aged 1-5 and environmental and sociodemographic risk factors in a rural Nile Delta hamlet. Inflammatory trachoma clustered in households, emphasising the child-to-child nature of transmission in the hamlet. Multiple logistic regression analysis revealed three factors predicting inflammatory trachoma in children: the absence of a latrine in the household, school-age siblings with inflammatory trachoma, and additional same-age siblings (with or without disease) in the household. In the Egyptian setting the presence of pit latrines in all houses, even when full and unscreened, might result in a reduction in trachoma prevalence in this population from the current 49% to 35%. The construction of pit latrines may offer the simplest and most acceptable environmental method for reducing trachoma in this trachoma endemic area.

Asunto(s)

RESUMEN

The Herpetic Eye Disease Study (HEDS) includes three double-masked, placebo-controlled clinical trials for potentially blinding herpes simplex virus (HSV) eye infections. One study compares a tapering dosage of topical prednisolone or placebo eye drops for HSV stromal keratitis (HEDS-SKN). Two other trials compare oral acyclovir to placebo capsules for HSV stromal keratitis (HEDS-SKS) or iridocyclitis (HEDS-IRT) in patients on a tapering dosage of topical prednisolone drops. All medications are administered for 10 weeks. Outcome is judged by time to recurrent disease or treatment failure. This paper presents the design, estimated sample size and recruitment as of July 25, 1990.

Asunto(s)

RESUMEN

Four days after corneal inoculation of mice with herpes simplex (type 1) virus (HSV), infected trigeminal ganglion cells with and without calcitonin gene-related peptide (CGRP) antigenicity were examined by electron microscopy in sections treated with colloidal gold labeled antibodies. Cells that contain CGRP were identified by the dense gold labeling of small vesicles about 100 nm in diameter. Adjacent thin sections were stained using an indirect colloidal gold immunocytochemical technique to reveal HSV-1 antigens. In CGRP-positive neurons, HSV antigens were located over both nuclear and cytoplasmic compartments. HSV label was found over cytoplasmic vesicles that were significantly larger than those labeled with anti-CGRP antisera; the HSV-containing vesicles ranged in profile diameter from less than 170 to greater than 400 nm. There was no overlap in the distribution of the two labels. Thus, for this time period, the organelles involved in transport of the endogenous neuropeptide and HSV appear to remain discrete. Furthermore, there was no significant difference in the distribution of HSV in CGRP-reactive and CGRP-negative trigeminal ganglion cells. Thus, there is no indication of a preferential distribution or limited replication of HSV in CGRP-positive neurons.

Asunto(s)

RESUMEN

The development and testing of candidate vaccines for trachoma are constrained because only humans and nonhuman primates are susceptible to conjunctival infection with Chlamydia trachomatis. Guinea pig inclusion conjunctivitis (GPIC), an analogous disease of guinea pigs, provides a useful, less expensive model to study ocular chlamydial infections. GPIC is caused by a Chlamydia psittaci strain whose external constituents are very similar to those of C. trachomatis. To develop a better model for studying GPIC immunity, conjunctival pockets were established under the abdominal skin of guinea pigs by subcutaneous implantation. Up to six implants could be produced in each animal. The success rate of implantation was 79.0% (n = 148). These pockets were then infected with GPIC. The organism was recovered from the autografts indicating local replication, and tests for serum antibody by microimmunofluorescence showed production of GPIC-specific antibody of IgG and IgM classes after infection. There was minimal antibody response after moderate inoculating doses to the implants, and the titers increased more slowly than after eye infection with GPIC; with higher concentration of the inoculum, however, the antibody response increased to the same levels as with the ocular challenge but more slowly. Inoculation of pockets with GPIC also produced acute inflammatory changes in infected autografts (n = 101). Histologic examination of infected grafts showed chlamydial inclusions in epithelial cells and significant infiltration with lymphocytes and polymorphonuclear cells. Subcutaneous autografts may provide a useful model for chronologic studies of chlamydial infection. The delayed immunologic response, however, suggests that these pockets of implanted epithelium do not have full access to the immune system.

Asunto(s)

Asunto(s)