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Biomedical subjects

B G Evans

Publications and source records attributed to B G Evans.

At least 37 records · Page 2Linked to original sources
PubMed2002

Numbers of adults with diagnosed HIV infection 1996-2005--adjusted totals and extrapolations for England, Wales and Northern Ireland.

Using data from the annual surveys of individuals receiving HIV related treatment or other care from 1996 to 2000, trends in prevalent numbers of diagnosed HIV infections have been extrapolated to the years 2001-05. Results show that the adjusted prevalent number for 1996 was 14,205 and that this has increased by 62% by the end of 2000, and will have increased by 139% by the end of 2005. The drivers for this increase have been the sustained rise in diagnoses in infections heterosexually acquired in sub-Saharan Africa and the continuing numbers of new diagnoses in men who have sex with men.

Adult↗
PubMed2002

Doncaster: the public health response to a local cluster of heterosexually acquired HIV infection.

In recent years, clusters of sexually transmitted HIV infection have attracted some media prominence in the UK. We describe our response to a local HIV cluster of five cases that acquired a high media profile. Practical difficulties encountered included: ensuring medical confidentiality in an outbreak control team which included many professional groups; handling a large volume of helpline calls; differing views on how specific health promotion should be; and the impact of summer leave on the control team's continuity. Following publicity, two further cases of HIV infection were found, bringing the total cluster to seven. Both later cases named the man at the centre of the cluster as a sexual partner. Of these two cases, one was local, identified as a direct result of the campaign. The other, living 170 miles distant in London, was identified as a result of increased media awareness. Eventually, the press named the man they thought to be the source case, which the outbreak control team had avoided doing. Good inter-disciplinary working made a co-ordinated public health response possible, and the 1,600 helpline calls dealt with served to reassure the public. Over 1,000 of the callers were advised to contact the Genito Urinary Medicine (GUM) department of their local hospital for counselling and testing of whom 772 took the advice. However, the longer-term effect on sexual behaviour was minimal as evidence by a subsequent survey.

Adult↗
PubMed2001

Emerging trends in the epidemiology of invasive mycoses in England and Wales (1990-9).

Invasive fungal infections are becoming an increasing public health problem owing to the growth in numbers of susceptible individuals. Despite this, the profile of mycoses remains low and there is no surveillance system specific to fungal infections currently existing in England and Wales. We analysed laboratory reports of deep-seated mycoses made to the Communicable Disease Surveillance Centre between 1990 and 1999 from England and Wales. A substantial rise in candidosis was seen during this period (6.76-13.70 reports per million population/year), particularly in the older age groups. Rates of cryptococcosis in males fluctuated over the decade but fell overall (1.05-0.66 per million population/year), whereas rates of female cases gradually rose up until 1998 (0.04-0.41 per million population/year). Reports of Pneumocystis carinii in men reduced substantially between 1990 and 1999 (2.77-0.42 per million population/year) but showed little change in women. Reports of aspergillosis fluctuated up until 1996, after which reports of male and female cases rose substantially (from 0.08 for both in 1996 to 1.92 and 1.69 per million population/year in 1999 for males and females respectively), largely accounted for by changes in reporting practice from one laboratory. Rates of invasive mycoses were generally higher in males than females, with overall male-to-female rate ratios of 1.32 (95% CI 1.25-1.40) for candidosis, 1.30 (95% CI 1.05-1.60) for aspergillosis, 3.99 (95% CI 2.93-5.53) for cryptococcosis and 4.36 (95% CI 3.47-5.53) for Pneumocystis carinii. The higher male than female rates of reports is likely to be a partial reflection of HIV epidemiology in England and Wales, although this does not fully explain the ratio in infants and older age groups. Lack of information on underlying predisposition prevents further identification of risk groups affected. Whilst substantial under-reporting of Pneumocystis carinii and Cryptococcus species was apparent, considerable numbers of superficial mycoses were misreported indicating a need for clarification of reporting guidelines. Efforts to enhance comprehensive laboratory reporting should be undertaken to maximize the utility of this approach for surveillance of deep-seated fungal infections.

Adolescent↗
PubMed2001

Use of blood culture vial specimens in intraoperative detection of infection.

A retrospective study was performed evaluating the results of three different intraoperative culture techniques and their diagnostic value in determining clinical infection in patients after a total joint replacement. Twenty-four patients (34 cases) met the selection criteria and were evaluated using intraoperatively collected tissue samples, swab samples, and fluid samples injected into standard blood culture vials. Results of the cultures of these specimens were compared with the clinical diagnoses to determine specificity, sensitivity, and accuracy of each technique. The current study suggests the use of fluid aspirate from intraoperative wounds immediately injected into blood culture vials is a highly specific, sensitive, and accurate diagnostic culture technique (100%, 92%, and 94%, respectively). The superiority of vial cultures is enhanced when organisms grown from the liquid media only are discounted as contaminants. This led to significant decreases in the sensitivity and accuracy of swab culture and tissue biopsy results when compared with vial culture results. Thus, vial cultures are a more cost-effective means for intraoperative detection of infection.

Adult↗
PubMed2001

The national CD4 surveillance scheme for England and Wales.

This paper describes a national surveillance scheme, began in 1995, designed to monitor immunosuppression associated with HIV infection in adults in England and Wales. Currently 60 out of 64 (94%) laboratories performing CD4 cell counts participate in the scheme. The database contains over 42,000 patient records with over 300,000 counts, taken between April 1984 and March 2000. Approximately half of the patient records in the CD4 database match with patient records in the UK database of diagnosed HIV infections; a large proportion of the unmatched patients in the CD4 database may not be HIV-infected. Close to 50% of both men who have sex with men and injecting drug users and two-thirds of those who acquired their infection heterosexually had CD4 cell counts below 350 cells/mm3 at the time of HIV diagnosis. The National CD4 Surveillance Scheme provides important information regarding the epidemiology of HIV infection such as the changes in patterns of early and late diagnosis. It should continue to be used in conjunction with the other HIV surveillance systems to present as complete a picture of the epidemic as possible.

Adolescent↗
PubMed2000

CD4 cell counts in adults with newly diagnosed HIV infection: results of surveillance in England and Wales, 1990-1998. CD4 Surveillance Scheme Advisory Group.

OBJECTIVES: To describe the distribution and changes in CD4 cell counts (both initial and subsequent) in HIV-infected persons over time and determine the factors influencing these counts. DESIGN: Reports were requested from laboratories measuring CD4 cell counts in England and Wales. Initial counts were analysed and median counts were followed over time. METHODS: Time trends and the relationship between initial CD4 cell count and age, sex, and HIV risk category were studied using quantile regression methods or chi-square tests. RESULTS: Between 1990 and 1998, 9553 adults were newly diagnosed with HIV infection and had a CD4 cell count within 6 months of HIV diagnosis. Over 50% of initial CD4 cell counts in each major risk category were below 350 cells/mm3. Older age (P < 0.001), male sex (P < 0.013) and heterosexual risk (P < 0.001) were independently associated with lower initial CD4 cell counts. For heterosexually infected adults, the median initial CD4 cell count was significantly negatively associated with the year of diagnosis (P = 0.03) and the median age increased through the time period examined (P < 0.001), whereas for men who have sex with men (MSM), there was no significant change in these values over time. For each year cohort of newly diagnosed individuals, the median CD4 cell count in subsequent years decreased until 1996 and then increased thereafter, consistent with a treatment effect. CONCLUSION: Across all major risk groups, a large proportion of HIV-infected adults are being diagnosed late in the course of HIV disease. For the heterosexually infected, the data suggest an ageing cohort effect, whereas for MSM the data are consistent with continuing transmission.

Adult↗
PubMed2000

Social and behavioural factors associated with HIV seroconversion in homosexual men attending a central London STD clinic: a feasibility study.

An unmatched retrospective case control study was conducted to test the feasibility of investigating social and behavioural factors which may have contributed to recent HIV seroconversion in a group of homosexual men. Participants, recruited from a London sexually transmitted disease (STD) clinic, were sexually active and had had a negative HIV test with a subsequent test (positive (cases) or negative (controls)) within three to 15 months. Twenty cases and 22 controls were recruited between February and October 1995. There was no difference between cases and controls in: the number of regular or casual sexual partners, the proportion who were unaware of their regular partners' serostatus (cases 60%, controls 59%), or the proportion who had known HIV-positive regular partners (cases 20%, controls 23%). A significant difference in sexual behaviour was found only when the HIV status of partners, if known, was taken into account: cases were more likely than controls to have had unprotected receptive anal intercourse with a partner not known to be HIV-negative (OR = 5.5, CI = 1.15-29.50). Fifty per cent of the cases and 27% of the controls acquired acute STDs between the two HIV tests. All participants achieved high self-efficacy scores, but the controls believed their peers placed a greater value on safer sex. Cases cited emotional issues and the use of drugs and alcohol as contributing to their seroconversion, whereas controls cited a commitment to safer sex and the avoidance of high-risk situations as contributing to their remaining HIV-negative. The results illustrate the importance of acknowledging the concept of 'negotiated safety' in studies of sexual behaviour; seroconversion was only associated with unprotected sex with a partner not known to be HIV-negative. Despite high self-efficacy scores, indicating the skills to negotiate safer sex, high levels of unsafe anal intercourse were reported. Differences between cases and controls included the importance of safer sex, periods of emotional vulnerability, influence of peers and the appropriate use of condoms. There is a need for these results to be confirmed in a larger and more powerful study.

Adult↗
PubMed2000

Survival after diagnosis of AIDS among adults resident in the United Kingdom in the era of multiple therapies.

The epidemiology of HIV and AIDS in the United Kingdom (UK) has changed markedly since highly active antiretroviral therapy (HAART) was introduced in 1996. HAART including protease inhibitors has considerably improved survival from AIDS diagnosis. The number of deaths of individuals with HIV infection in the UK, reported within 12 months of the end of the year of death, have decreased between 1995 and 1998. Concurrently AIDS diagnoses, reported within 12 months of the end of the year of diagnosis, have declined whilst diagnoses of HIV infection, similarly reported, have risen. Data from 13,689 adult AIDS cases diagnosed up to the end of 1996 were analysed. The overall median survival from AIDS diagnosis to death was 19.3 months. Over 50% of the cases diagnosed in 1996 were alive at the end of the survey therefore median survival exceeds 24 months, the maximum follow up time for the cohort. The opportunity for receiving HAART was modelled in three time periods: pre-multiple therapies (before September 1995), multiple reverse-transcriptase inhibitor therapy available (September 1995 to March 1996), and multiple therapy including protease inhibitors available (April 1996 onwards). Survival rates improved significantly among female heterosexuals and men who have sex with men when multiple therapy including protease inhibitors became available.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Pre-AIDS mortality in HIV-infected individuals in England, Wales and Northern Ireland, 1982-1996.

OBJECTIVE: To assess pre-AIDS mortality in HIV-infected patients in England, Wales and Northern Ireland during the period 1982-1996. DESIGN: Surveillance data on pre-AIDS and AIDS deaths reported to the PHLS-AIDS Centre were analysed. METHODS: Pre-AIDS mortality was estimated as the proportion of pre-AIDS deaths among all deaths in HIV-infected people. Trends over time in the number of pre-AIDS and AIDS deaths were compared using Poisson regression with logarithmic link. Causes of pre-AIDS deaths were recorded. Comparisons were made between the pre-AIDS and the AIDS death groups by logistic regression for: age, location of residence at death, year of death and risk exposure. RESULTS: Four-hundred and sixty-eight pre-AIDS deaths and 8574 AIDS deaths were identified. Pre-AIDS mortality accounted for 5.0% of HIV-related deaths. Trends over time in the number of pre-AIDS and AIDS deaths were not significantly different (P=0.11). Reported causes of pre-AIDS death included pneumonia (92), liver disease (62), septicaemia (51), malignancies (49), suicide (45), cardiopulmonary causes (46), haemorrhage (42), overdose (24) and accidental causes (24). Factors positively associated with pre-AIDS death were injecting drug use, haemophilia and blood transfusion, residence outside the Thames regions, and death at an older age. CONCLUSIONS: Pre-AIDS mortality represents a substantial proportion of HIV mortality, particularly where injecting drug use is a frequent route of HIV transmission.

Adult↗
PubMed1998

Unusual HIV transmissions through blood contact: analysis of cases reported in the United Kingdom to December 1997.

It is important to establish the likely route of infection for all reported HIV infected individuals if the HIV epidemic is to be understood. Investigating routes of infection may bring unusual infection routes to light. Steps have been taken in the United Kingdom (UK) to establish the likely mode of HIV acquisition for everyone reported as infected. If an initial report is incomplete the clinician caring for the patient is asked for relevant information. If further information is needed, and an interview is feasible and acceptable to both the clinician and the patient, information is collected from the patient through face-to-face semistructured interview. Such follow up has identified 19 cases (among 34,000 records of individuals with HIV and/or AIDS for which probable routes of infection have established) who seem to have acquired HIV infection in unusual circumstances. Seven of the 19 cases described in this paper are thought to have acquired HIV infection in the UK, two in Spain, and ten in countries with a high prevalence of HIV infection. This paper describes the circumstances in which HIV transmission is believed to have occurred.

Adult↗
PubMed1998

Fatal outcome of transmission of hepatitis B from an e antigen negative surgeon.

Investigation of the death of a 77 year old woman from acute hepatitis B infection revealed that she had undergone orthopaedic surgery two and a half months earlier. The surgeon was found to be a hepatitis B surface antigen carrier, hepatitis B e antigen (HBeAg)negative, but with antibodies to HBeAg. Viruses from the surgeon and the patient were identical, apart from a single nucleotide substitution. Both had a precore mutation, which prevents expression of e antigen. A look back exercise was undertaken on the patients operated on by the surgeon during the previous year. The surgeon had performed exposure prone procedures on 253 patients, 188 of whom provided blood specimens. No HBsAg carriers were detected, and no serological markers of recent transmission were found.

Aged↗
PubMed1997

HIV antibody assay that gave false negative results: multicentre collaborative study.

OBJECTIVE: To identify false negative results arising from the use of a commercial kit to detect antibody to HIV-1 and HIV-2 between July 1995 and March 1996. DESIGN: The 56 laboratories in the United Kingdom that were using the assay were asked to retrieve and retest specimens with an alternative assay for HIV-1 and HIV-2. Details of false negative results were obtained and these serum samples further investigated. SUBJECTS: 24,181 patients tested with the assay who were reported as being negative for HIV antibody. An additional 497 patients were confirmed as HIV positive with the assay. RESULTS: Serum samples of 20,973 of the patients were retested, and four patients were found to have had false negative results with the kit; three further patients were found to have had false negative results in the course of other laboratory testing. The seven patients with false negative results with the kit were of diverse risk group and HIV-1 subtype. Four had evidence of recent HIV infection. CONCLUSION: The commercial kit had a sensitivity of 99.2% (497/501), or less if the additional three patients with false negative results were taken into account.

False Negative Reactions↗
PubMed1997

Survival of adults with AIDS in the United Kingdom.

Accurate estimates of expected survival times and survival rates of AIDS patients are important both for estimating the prognosis of individuals and for monitoring the progress of the HIV/AIDS epidemic as new treatments are introduced. They are also needed for projecting future numbers of AIDS cases. Data on reported AIDS cases held at the PHLS AIDS Centre at the Communicable Disease Surveillance Centre and the Scottish Centre for Infection and Environmental Health confirmed the time, age, and reporting delay effects identified in earlier analyses of the United Kingdom AIDS database. The duration of survival after AIDS is diagnosed has improved since the epidemic began--median survival was 10.6 months in cases diagnosed before 1987 and has been at least 18.4 months in cases diagnosed each year since then. People who are diagnosed younger live longer--median survival fell from 21.6 months at age 15 to 29 to 12.6 months at age 45 or over. Delay in reporting AIDS cases adversely affects survival estimates for cases reported in recent years. Survival was longer in cases reported over a year after diagnosis of AIDS--23.7 months compared with 16.9 months in those reported less than a year after diagnosis. The experience of the hospital, measured by its cumulative AIDS caseload, was an important factor in the survival of men who have sex with men presenting with Kaposi's sarcoma alone or 'other' diagnoses--survival was shorter for cases reported from smaller centres. Men who have sex with men with Pneumocystis carinii pneumonia alone or other opportunistic infections alone who were known to be HIV positive before being diagnosed with AIDS had a shorter survival after being diagnosed than those who were unaware of their HIV infection. This supports the hypothesis that treatment for HIV infection and prophylaxis may extend the period before AIDS develops but reduce the period between developing AIDS and dying.

Acquired Immunodeficiency Syndrome↗
PubMed1996

AIDS defining diseases in the UK: the impact of PCP prophylaxis and twelve years of change.

We examined all reports of adult AIDS cases made to the 2 national surveillance centres in the UK for changes in AIDS defining conditions between January 1982 and September 1994. Differences and changes among persons diagnosed since January 1988 who had and had not been aware of their HIV infection prior to their AIDS diagnosis were of particular interest. Pneumocystis carinii pneumonia (PCP) is the AIDS defining disease most often reported at the initial AIDS diagnosis. Its proportion of all AIDS cases has increased significantly between January 1982 and December 1987 and decreased markedly thereafter. Since January 1988 a significant decrease in the proportion of cases diagnosed with cryptosporidial infection was also observed while increases were observed in the proportion of cases diagnosed with: HIV wasting (chi(1)(2) = 5.56) PML (chi(1)(2) = 19.47), mycobacterium avium complex (chi(1)(2) = 35.76) and pulmonary tuberculosis (chi(1)(2) = 144.0). For cases diagnosed between January 1988 and September 1994, PCP was more likely to be diagnosed in patients previously unaware of their HIV infection (P < 0.01) as was extrapulmonary TB (P < 0.01). In contrast, the following diseases were more likely to be diagnosed in patients already aware of their HIV infection prior to the diagnosis of AIDS: oesophageal candidiasis (P < 0.001), HIV wasting (P = 0.07), mycobacterium avium complex (P = 0.0001), cytomegalovirus disease (P < 0.001), HIV encephalopathy (P = 0.0009) and cryptosporidial infection (P = 0.02). Prophylaxis and anti-retroviral therapy appear to have had a significant impact on the temporal changes of the most frequently diagnosed AIDS diseases. While PCP prophylaxis has substantially reduced the likelihood of a PCP diagnosis at AIDS, the corresponding increase in other opportunistic infections suggests that there may be a need for improved prophylaxis for these conditions.

AIDS Dementia Complex↗