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Allen Foster

Publications and source records attributed to Allen Foster.

13 recordsLinked to original sources
PubMed2003

Strategies for control of trachoma: observational study with quantitative PCR.

BACKGROUND: Antibiotics are an important part of WHO's strategy to eliminate trachoma as a blinding disease by 2020. At present, who needs to be treated is unclear. We aimed to establish the burden of ocular Chlamydia trachomatis in three trachoma-endemic communities in Tanzania and The Gambia with real-time quantitative PCR. METHODS: Conjunctival swabs were obtained at examination from 3146 individuals. Swabs were first tested by the qualitative Amplicor PCR, which is known to be highly sensitive. In positive samples, the number of copies of omp1 (a single-copy C trachomatis gene) was measured by quantitative PCR. FINDINGS: Children had the highest ocular loads of C trachomatis, although the amount of pooling in young age groups was less striking at the site with the lowest trachoma frequency. Individuals with intense inflammatory trachoma had higher loads than did those with other conjunctival signs. At the site with the highest prevalence of trachoma, 48 of 93 (52%) individuals with conjunctival scarring but no sign of active disease were positive for ocular chlamydiae. INTERPRETATION: Children younger than 10 years old, and those with intense inflammatory trachoma, probably represent the major source of ocular C trachomatis infection in endemic communities. Success of antibiotic distribution programmes could depend on these groups receiving effective treatment.

Adolescent↗
PubMed2003

Trachoma.

Trachoma is the most common infectious cause of blindness. It is caused by ocular serovars of Chlamydia trachomatis. Transmission is favoured in poor communities, where crowding is common and access to water and sanitation inadequate. Repeated reinfection over many years causes dense scarring of the upper eyelid. The resultant inversion of the lashes abrades the eyeball, and the abrasion leads to corneal opacification and visual impairment. The host immune response is probably at least partly the cause of this process. The "SAFE" strategy is used for the control of trachoma: surgery for in-turned lashes, antibiotics for active disease, facial cleanliness, and environmental improvement. The demonstration that a single oral dose of the antibiotic azithromycin is as effective as 6 weeks of topical tetracycline was an important advance in trachoma control. By means of the SAFE strategy, WHO and its partners aim to eliminate trachoma as a public-health problem by the year 2020.

Chlamydia trachomatis↗
PubMed2003

The magnitude and cost of global blindness: an increasing problem that can be alleviated.

PURPOSE: To identify the potential effect on global economic productivity of successful interventions, that are planned as part of the "VISION 2020-right to sight" initiative. The initiative aims to eliminate avoidable blindness. DESIGN: This study used economic and epidemiologic modeling. METHODS: Existing data and assumptions about blindness prevalence, national populations, gross domestic product (GDP) per capita, labor force participation, and unemployment rates were used to project the economic productivity loss associated with unaccommodated blindness. RESULTS: Without extra interventions, the global number of blind individuals would increase from 44 million in the year 2000 to 76 million in 2020. A successful VISION 2020 initiative would result in only 24 million blind in 2020 and lead to 429 million blind person-years avoided. A conservative estimate of the economic gain is $102 billion. CONCLUSIONS: The VISION 2020 initiative has the potential to increase global economic productivity.

Adolescent↗
PubMed2003

A critical review of the SAFE strategy for the prevention of blinding trachoma.

Trachoma is an ocular disease caused by repeated infection with Chlamydia trachomatis. It is the leading cause of infectious blindness globally, responsible for 5.9 million cases of blindness. Although trachomatous blindness is untreatable, it is eminently possible to prevent and the World Health Organization promotes the use of the SAFE strategy (surgery to treat end-stage disease, antibiotics to reduce the reservoir of infection, facial cleanliness, and environmental improvement to reduce transmission of C trachomatis) for this purpose. In this review we have assessed the evidence base supporting the elements of the SAFE strategy. We find strong support for the efficacy of the surgery and antibiotics components, although the optimal antibiotic regimens have not yet been established. The evidence for an effect of health education and environmental improvement is weaker, and depends mostly on cross-sectional observational studies.

Anti-Bacterial Agents↗
PubMed2003

Cataract blindness in Paraguay--results of a national survey.

PURPOSE: To estimate the burden of visual loss and blindness due to cataract in people aged 50 years and over in Paraguay. METHODS: Forty clusters of 60 persons each who were 50 years and older (2400 eligible persons) were selected by systematic random sampling from the entire population of Paraguay. A total of 2136 persons were examined (89% coverage). RESULTS: For the population 50 years and over, the age- and gender-adjusted prevalence of bilateral blindness (VA < 3/60 with available correction) was 3.14% (95% CI: 2.2-4.4). The adjusted prevalence of bilateral cataract blindness (VA < 3/60) was 2.01% (95% CI: 1.3-3.0), making cataract the major cause of bilateral blindness in this age group (64%). The adjusted prevalence of bilateral severe visual impairment (VA < 6/60 with available correction) was 5.17% (95% CI: 3.9-6.7) and the adjusted prevalence of severe visual impairment due to bilateral cataract (VA < 6/60) was 3.09% (95% CI: 2.2-4.3). The cataract surgical coverage (persons) was 44% for bilaterally blind persons with VA < 3/60; 36% for persons with bilateral VA < 6/60; and 28% for any eye with VA < 6/60 due to cataract. With IOL implantation, 77% of the operated eyes could see 6/18, against 46% of the non-IOLs (p < 0.005), a significant better outcome. CONCLUSION: There is a need to increase the cataract surgical coverage in Paraguay. The number of eye surgeons is adequate but the accessibility of cataract surgical services in rural areas and the affordability of surgery to large sections of society are major constraints.

Aged↗
PubMed2003

Antibiotic dosage in trachoma control programs: height as a surrogate for weight in children.

PURPOSE: National programs for trachoma control are implementing mass treatment programs in which azithromycin is used as part of the control strategy. Dose is determined by weight, which can be difficult to determine in field conditions. The purposes of this study were to determine whether an accurate dose could be determined by using height as a surrogate for weight and whether a single model of height-based dosage would be applicable in more than one setting. METHODS: Data on height, weight, age, and gender of 5558 children aged 6 months to15 years were obtained from Kongwa and Rombo, Tanzania; Malakal, Sudan; Jareng, The Gambia; and Daboya, Ghana. Models for predicting weight by measuring height were developed that incorporated country-specific parameters. Doses of azithromycin assumed suspension of 40 mg/mL and 250-mg tablets that could be halved. Tolerance limits were defined as 15 to 30 mg/kg. RESULTS: A regression model, predicting log weight as a function of log height, was the best fit and explained 94% of the variance. In children less than 1 year of age or 60 cm in height, dose determined by weight was preferred. Dosage by height resulted in more than 97% of children receiving doses within the tolerance limits. Children aged 1 to 2 years were the group most likely to be over- or undermedicated, but this occurred in only 6% of this age group. CONCLUSIONS: Height-based determination of dosage of azithromycin in trachoma control programs appears to be feasible, using the height-based schedule proposed. One model was adequate for all the countries in the study. Further expansion to other countries is warranted.

Adolescent↗
PubMed2003

Which members of a community need antibiotics to control trachoma? Conjunctival Chlamydia trachomatis infection load in Gambian villages.

PURPOSE: Trachoma is the leading cause of infectious blindness worldwide. Control strategies target antibiotic therapy to individuals likely to be infected with Chlamydia trachomatis on the basis of clinical signs. However, many studies have found chlamydial infection in the absence of clinical disease. It has been unclear whether such individuals represent a significant reservoir of infection. In the current study, a quantitative polymerase chain reaction (PCR) assay was used to investigate the distribution and determinants of chlamydial infection load in an endemic community, and the findings were used to evaluate the potential effectiveness of different control strategies. METHODS: Members of a trachoma-endemic community (n = 1319) in a rural area of The Gambia were examined for signs of disease, and tarsal conjunctival swab samples were collected. C. trachomatis was initially detected by qualitative PCR. The load of infection was then estimated by real-time quantitative PCR. RESULTS: Chlamydial infection was detected in 7.2% of the population. The distribution of infection load was skewed, with a few individuals having high loads. Only 24% of infected individuals had signs of active trachoma. Infection loads were higher in those with clinically active disease and were highest among those with severe inflammatory trachoma. High infection loads were associated with having no accessible latrine and living with a person with active disease. CONCLUSIONS: In this low-prevalence setting, infected individuals without signs of active trachoma constitute a significant reservoir of infection. Treatment of a defined unit of people who live with someone with clinically active trachoma would effectively target antibiotic treatment to infected people without signs of disease.

Adolescent↗
PubMed2003

Gastrointestinal symptoms are more intense in morbidly obese patients and are improved with laparoscopic Roux-en-Y gastric bypass.

BACKGROUND: Currently there are few reports comparing gastrointestinal (GI) symptoms in the morbidly obese versus control subjects or the effect of laparoscopic Roux-en-Y gastric bypass (LRYGBP) on such symptoms. METHODS: A previously validated, 19-point GI symptom questionnaire was administered prospectively to each patient undergoing LRYGBP, and the questionnaire was re-administered 6 months postoperatively. Six symptom clusters (abdominal pain, irritable bowel [IBS], reflux, gastroesophageal reflux disease [GERD], sleep disturbances, and dysphagia) were compared in the following manner using Students t-test: 1) Control vs. Preop, 2) Control vs Postop, and 3) Preop vs Postop. Results are expressed as mean +/- standard deviation, significance P=0.05. RESULTS: 43 patients (40 female and 3 male, age 37.3 +/- 8.6, BMI 47.8 +/- 4.9) completed the questionnaire preoperatively, and 36 patients (34 female, 2 male, BMI 31.6 +/- 5.3) completed the questionnaire 6 months postoperatively, for a response-rate of 84%. Abdominal pain, IBS, reflux, GERD and sleep disturbance symptoms were significantly worse in preop versus controls. Dysphagia was not different. Postop vs preop scores revealed abdominal pain, IBS, GERD, reflux, and sleep disturbance symptoms to be improved significantly. Dysphagia was not significantly different. Only dysphagia was worse when comparing postoperative to controls. No other symptom cluster was significantly different in controls vs postoperative. CONCLUSIONS: Morbidly obese patients experience more intense GI symptoms than control subjects, and many of these symptoms return to control levels 6 months after LRYGBP. Dysphagia is equivalent to control subjects preoperatively but increases significantly after LRYGBP. This data suggests another quality-of-life improvement (relief of GI symptoms) for morbidly obese patients. Further follow-up is needed to document the long-term reduction of GI symptoms.

Adult↗
PubMed2002

Environmental risk factors in congenital malformations of the eye.

Developmental eye defects such as coloboma are a significant cause of visual morbidity in children, and are more common in India than elsewhere. The possible role of environmental factors in the aetiology of these conditions was investigated by studying birth order, symptoms of vitamin A deficiency (night blindness), drug use and maternal illness in pregnancy, rubella antibodies and exposure to agricultural chemicals. Through hospital records and community-based rehabilitation programmes in Andhra Pradesh, children with colobomata were recruited from schools for the blind. Eighty-three mothers of affected children were interviewed. The results showed that 43% of parents were consanguineous, that 19% had a positive family history and that the frequency of coloboma was highest in second-born children. Eleven (16%) mothers had a history of night blindness while pregnant with the affected child; seven (8%) took medication during the 1st trimester, abortifacients in two cases; three reported fever in the 1st trimester; and 11 (13%) reported exposure to agricultural chemicals.

Abnormalities, Multiple↗
PubMed2002

Longitudinal study of trachomatous trichiasis in The Gambia: barriers to acceptance of surgery.

PURPOSE: Investigation of compliance with surgery for trachomatous trichiasis has become a priority of the World Health Organization. This study was conducted to investigate attitudes toward trichiasis and its treatment and to determine the rate of surgical uptake in The Gambia. METHODS: A 1-year longitudinal study was performed in 190 subjects with trichiasis. Persons with major trichiasis (involving five lashes or more) were referred for surgery, and those with minor trichiasis were advised to epilate. Outcome measures included attitudes toward trichiasis and its treatment, reported barriers to surgical uptake, acceptance rates for surgery, and factors affecting acceptance. RESULTS: Twenty-three percent (95% confidence interval [CI] 16.5%-30.6%) of subjects with major trichiasis attended for surgery during the year. Degree of ignorance about surgery, symptoms impeding work, and a multiple income source for the head of household predicted attendance. Reported lack of time predicted nonattendance. Sixty-eight percent of patients who had undergone surgery were trichiasis free at last follow-up. CONCLUSIONS: Poor attendance for surgery remains a problem in The Gambia. Barriers include ignorance and lack of time and money. Health education and surgical delivery strategies are needed to overcome these barriers. Regular audit of surgical results is necessary, with retraining where indicated.

Eyelashes↗
PubMedDate not supplied

Gastrointestinal symptomatic outcome after laparoscopic Roux-en-Y gastric bypass.

Laparoscopic Roux-en-Y (RY) gastric bypass is an effective treatment for morbid obesity. However, little information is available regarding the gastrointestinal symptomatic outcome after laparoscopic RY gastric bypass for morbid obesity. The purpose of this study is to identify changes occurring in gastrointestinal symptoms after laparoscopic RY gastric bypass. A previously validated, 19-point gastrointestinal symptom questionnaire was administered prospectively to each patient seen for surgical consultation to treat morbid obesity. Patients rated the degree to which each symptom affected their lives on a 0 to 100 mm Liekert scale with 0 indicating absence of a symptom, 33 indicating the symptom was present occasionally, 67 indicating the symptom occurred frequently, and 100 indicating the symptom was continuous. The same survey was readministered 6 months postoperatively. The mean of each symptom (preoperative vs. postoperative value) was compared using Student's t test with significance at P<0.05. Forty-three preoperative patients (age 37.3+/-8.6 years; body mass index 47.8+/-4.9) and thirty-five, 6 months' postoperative patients (81% follow-up; body mass index 31.6+/-5.3) completed the questionnaire. The result for each symptom is expressed as mean+/-standard deviation of preoperative vs. postoperative scores. Significantly different symptoms include the following: abdominal pain 23.3+/-26.4 vs. 8.6+/-13.5, P=0.003; heartburn 34.0+/-26.6 vs. 8.0+/-14.0, P=0.0001; acid regurgitation 28.1+/-24.0 vs. 10.7+/-21.0, P=0.001; gnawing in epigastrium 19.3+/-22.7 vs. 7.5+/-16.0, P=0.01; abdominal distention 38.2+/-31.5 vs. 11.1+/-19.2, P=0.0001; eructation 27.7+/-24.4 vs. 15.5+/-16.9, P=0.01; increased flatus 40.2+/-25.7 vs. 25.2+/-25.3, P=0.005; decreased stools 5.4+/-16.8 vs. 17.4+/-20.0, P=0.0005; increased stools 23.9+/-26.7 vs. 6.5+/-11.7, P=0.0005; loose stools 29.7+/-26.5 vs. 17.5+/-20.0, P=0.03; urgent defecation 34.3+/-26.5 vs. 14.3+/-19.3, P=0.0009; difficulty falling asleep 44.1+/-38.4 vs. 27.5+/-32.9, P=0.05; insomnia 42.4+/-36.2 vs. 21.6+/-30.5, P=0.008; and rested on awakening 65.1+/-33.8 vs. 30.5+/-28.8, P=0.0001. Symptoms that did not significantly change included the following: nausea/vomiting 17.2+/-22.7 vs. 22.1+/-19.9, P=0.33; borborygmus 28.8+/-25.2 vs. 26.8+/-29.7, P=0.75; hard stools 10.3+/-22.9 vs. 7.1+/-18.6, P=0.56; incomplete evacuation of stool 17.2+/-22.8 vs. 13.4+/-21.7, P=0.45; and dysphagia 10.9+/-15.6 vs. 17.7+/-28.4, P=0.18. Laparoscopic RY gastric bypass significantly improves many gastrointestinal symptoms experienced by morbidly obese patients without adversely affecting any of the measured parameters. This information is useful in preoperative counseling to assure patients of overall symptomatic improvement after this operation in addition to significant weight loss and improvement of comorbid conditions.

Adult↗