Biomedical subjects
D Mabey
Publications and source records attributed to D Mabey.
Chlamydia pneumoniae and atherosclerosis.
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Ivermectin and onchocercal optic nerve lesions.
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HIV infection among heterosexual travellers attending the Hospital for Tropical Diseases, London.
OBJECTIVE: To determine the prevalence of HIV infection in travellers attending the Hospital for Tropical Diseases, London, and to assess correlates and behavioural risk factors for infection. DESIGN: All patients tested for HIV infection during a 28-month period were included. Information was obtained from clinical records and standardised serological request forms. SETTING: Hospital for Tropical Diseases, London, UK. SUBJECTS: 298 patients (in-patient and out-patient) were tested. RESULTS: 258 of those tested were exclusively heterosexual and not injecting drug users. 5.4% of these were HIV-1 antibody positive. Rates in those originating from the UK and those from outside the UK were 1.8% and 33.2% respectively. Most non-UK citizens were symptomatic when tested; UK citizens were generally tested as part of a routine screening, therefore the two groups are not comparable. Rates of risk behaviour were high in both groups. CONCLUSION: The rate of HIV infection in heterosexual travellers was 5.4%. Amongst UK citizens the rate was 1.8%. All travellers should be made aware of the potential risk of acquiring HIV infection through sexual contact.
The value of urine specimens in screening for male urethritis and its microbial aetiologies in Tanzania.
OBJECTIVE: To evaluate the first void urine (FVU) specimen in screening for urethritis and its microbial aetiologies in a male African population in which urinary schistosomiasis is also prevalent. PATIENTS AND METHODS: Two hundred and forty eight males aged 15-54 years provided FVU specimens: 55 patients from a clinic for sexually transmitted diseases (STD), 151 patients from a medical outpatient clinic and 42 villagers from an area of high endemicity for S haematobium. Specimens were tested for leucocyte esterase (LE) using a dipstick (Nephur-Test+Leuco, Boehringer-Mannheim France SA). Ova of S haematobium were sought in terminal urine samples from all subjects. For all STD patients, and all medical outpatients with a positive LE test, urine and urethral swabs were tested for Chlamydia trachomatis antigen, and urethral swabs were tested for Neisseria gonorrhoeae by gram stain and isolation. RESULTS: The prevalence of LE positivity was 38/41 in STD patients with urethral signs or symptoms (93%), 5/14 among other STD patients (36%), 21/151 among medical outpatients (15%) and 13/42 among villagers (31%). As a screening test for urethral infection (detection of gonorrhoea or chlamydia and/or > or = 5 polymorphs per high power field on gram stain) the LE test had a sensitivity of 94% and a specificity of 53% among STD patients. Of 24 STD patients with gonococcal or chlamydial infection, 23 had a positive LE test (96%). Among general medical outpatients, 12 of 22 with a positive LE test had either conventionally defined urethritis or gonococcal or chlamydial infection, giving a positive predictive value of 55% for the LE test in this group. Of 18 subjects in all groups with urinary schistosomiasis nine had a positive LE test (50%), although three of these also had gonorrhoea. Chlamydial antigen was detected in the FVU specimen of all six subjects in whom it was detected in a urethral swab, and in an additional three subjects in the outpatient group. CONCLUSIONS: The FVU, which is an easily collected and non-invasive specimen, can provide valuable information on the prevalence of urethritis and on its microbial aetiology among the general male population in African countries.
Persisting inapparent chlamydial infection in a trachoma endemic community in The Gambia.
In a Gambian village with endemic trachoma, C. trachomatis was isolated from some 50% of children with active trachoma but from only 1% of adults with scarring sequelae. One possibility is that individuals with progressive scarring disease have clinically inapparent, non-productive infection which cannot be detected by cell culture. In whole village survey, 12% of 808 people carried ocular chlamydial antigen detected by EIA. Around 70% of antigen positive children were clinically active. By contrast, for adults age greater than 25 years, only 10% of antigen positives were clinically active. Antigen positive adults were twice as likely to develop scarring disease and longitudinal studies suggest that they are intermittently infectious. Implications for the pathology and prevention of trachoma are discussed.
Danger of hypotonic half-Darrow's solution.
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Chlamydial and gonococcal ophthalmia neonatorum in The Gambia.
Swabs were taken for isolation of Chlamydia trachomatis and Neisseria gonorrhoeae from 112 infants with ophthalmia neonatorum attending a hospital in The Gambia. C. trachomatis was isolated from 37 (33%) and N. gonorrhoeae from 28 (25%), with both organisms being present in three cases (3%). A prospective study of 335 neonates was also undertaken in a Gambian town. Fifty-five infants (16%) showed clinical evidence of ophthalmia neonatorum. C. trachomatis was isolated from nine of these (16%) and N. gonorrhoeae from seven (13%).
Histoplasma duboisii infection of bone.
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Trachoma and water use; a case control study in a Gambian village.
Trachoma is prevalent in many arid areas but data assessing the relationship between water use and trachoma are very scarce. This study compared 18 families having one or more active trachoma cases among the children with 16 trachoma-free families in the same village with respect to water use. Potential confounders such as family size, distance to water source, socio-economic indicators, and hygiene behaviour were assessed in the 2 groups. The families with trachoma were found to use significantly less water per person per day for washing children than did the control group (P = 0.033) with no evidence of confounding by the other measured variables. Low amounts of water for washing were also associated with unclean faces and impetigo in the children. If such a relationship can be substantiated it might provide the basis for effective and cheap interventions against trachoma.
Sexually transmitted diseases in developing countries.
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Cost-effectiveness of improved treatment services for sexually transmitted diseases in preventing HIV-1 infection in Mwanza Region, Tanzania.
BACKGROUND: A community-randomised trial was undertaken to assess the impact, cost, and cost-effectiveness of averting HIV-1 infection through improved management of sexually transmitted diseases (STDs) by primary-health-care workers in Mwanza Region, Tanzania. METHODS: The impact of improved treatment services for STDs on HIV-1 incidence was assessed by comparison of six intervention communities with six matched communities. We followed up a random cohort of 12,537 adults aged 15-54 years for 2 years to record incidence of HIV-1 infection. The total and incremental costs of the intervention were estimated (ingredients approach) and used to calculate the total cost per case treated, the incremental cost per HIV-1 infection averted, and the incremental cost per disability-adjusted life-year (DALY) saved. FINDINGS: During 2 years of follow-up, 11,632 cases of STDs were treated in the intervention health units. The baseline prevalence of HIV-1 infection was 4%. The incidence of HIV-1 infection during the 2 years was 1.16% in the intervention communities and 1.86% in the comparison communities. An estimated 252 HIV-1 infections were averted each year. The total annual cost of the intervention was US$59,060 (1993 prices), equivalent to $0.39 per head of population served. The cost for STD case treated was $10.15, of which the drug cost was $2.11. The incremental annual cost of the intervention was $54,839, equivalent to $217.62 per HIV-1 infection averted and $10.33 per DALY saved (based on Tanzanian life expectancy) or $9.45 per DALY saved (based on the assumptions of the World Development Report). In a sensitivity analysis of factors influencing cost-effectiveness, cost per DALY saved ranged from $2.51 to $47.86. INTERPRETATION: Improved management of STDs in rural health units reduced the incidence of HIV-1 infection in the general population by about 40%. The estimated cost-effectiveness of this intervention ($10 per DALY) compares favourably with that of, for example, childhood immunisation programmes ($12-17 per DALY). Cost-effectiveness should be further improved when the intervention is applied on a larger scale. Resources should be made available for this highly cost-effective HIV control strategy.
Sex and travel.
Sexually transmitted diseases have been associated with travellers since they were first described. The scale of international travel has increased enormously in the past 50 years, enabling sexually transmitted pathogens to spread with unprecedented speed. This article assesses the importance of international travel as a risk factor for human immunodeficiency virus (HIV) infection among heterosexuals in the UK, and suggests possible strategies for the prevention of HIV infection in travellers.