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Biomedical subjects

G Garnett

Publications and source records attributed to G Garnett.

15 recordsLinked to original sources
PubMed2006

Utility of the Determine Syphilis TP rapid test in commercial sex venues in Peru.

OBJECTIVES: This study sought to evaluate the utility of the Determine Syphilis TP test performed in Peruvian commercial sex venues for the detection of active syphilis; and determine the feasibility of integrating rapid syphilis testing for female sex workers (FSW) into existing health outreach services. METHODS: We tested 3586 female sex workers for syphilis by Determine in the field using whole blood fingerstick, and by rapid plasma reagin (RPR) and Treponema pallidum haemagglutination assay (TPHA) in a central laboratory in Lima using sera. RESULTS: 97.4% of the FSW offered rapid syphilis testing participated; and among those who tested positive, 87% visited the local health centre for treatment. More than twice as many specimens were RPR reactive using serum in Lima (5.7%) than tested positive by whole blood Determine in the field (2.8%), and although most were confirmed by TPHA, only a small proportion (0.7%) were RPR reactive at >or=1:8 dilutions, and likely indicating active syphilis. Sensitivity, specificity and positive predictive value of the Determine Syphilis TP test in whole blood when compared to serum RPR reactivity at any dilution confirmed by TPHA as the gold standard were 39.3%, 99.2% and 71.4%, respectively. Sensitivity improved to 64.0% when using serum RPR >or=1:8 confirmed by TPHA. Invalid tests were rare (0.3%). CONCLUSIONS: Rapid syphilis testing in sex work venues proved feasible, but Determine using whole blood obtained by fingerstick was substantially less sensitive than reported in previous laboratory-based studies using serum. Although easy to perform in outreach venues, the utility of this rapid syphilis test was relatively low in settings where a large proportion of the targeted population has been previously tested and treated.

Feasibility Studies↗
PubMed2006

Improving projections at the country level: the UNAIDS Estimation and Projection Package 2005.

BACKGROUND: UNAIDS has developed the Estimation and Projection Package (EPP) as a tool for national programmes to use for making national estimates and short term projections of HIV prevalence. EPP provides direct input to Spectrum, which produces incidence, deaths, and AIDS impacts. METHODS: The latest version, EPP 2005, includes substantial methodological improvements over the previous version. These include: (1) parallel, but unique, interfaces for generalised and concentrated epidemics; (2) use of maximum likelihood fitting procedures; (3) a new procedure, known as level fits, adjusting for expansion of national surveillance systems into lower prevalence sites; (4) provisions for handling turnover in at-risk populations, including the reassignment of HIV positive former members to lower risk populations; and (5) user-defined calibration to HIV prevalence levels from general population or other epidemiological surveys. RESULTS: Following regional training in mid 2005, this new version has been applied by many national programmes to make their end of 2005 estimates of HIV infections. UNAIDS has combined these national estimates to form the 2005 global HIV and AIDS estimates. CONCLUSION: EPP 2005 is a substantial improvement over previous versions, forming a solid base for the next round of modifications. Proposed modifications for that next version are presented for the reader's information.

Disease Outbreaks↗
PubMed2004

The UNAIDS Estimation and Projection Package: a software package to estimate and project national HIV epidemics.

This paper describes the Estimation and Projection Package (EPP) for estimating and projecting HIV prevalence levels in countries with generalised epidemics. The paper gives an overall summary of the software and interface. It describes the process of defining and modelling a national epidemic in terms of locally relevant sub-epidemics and the four epidemiological parameters used to fit a curve to produce the prevalence trends in the epidemic. It also provides an example of using the EPP in a country with a generalised epidemic. The paper discusses the strengths and weaknesses of the software and its envisaged future developments.

Adolescent↗
PubMed2004

Uncertainty in estimates of HIV/AIDS: the estimation and application of plausibility bounds.

OBJECTIVES: To establish the accuracy of the country specific estimates of HIV prevalence, incidence, and AIDS mortality published every 2 years by UNAIDS and WHO. METHODS: We review sources of error in the data used to generate national HIV/AIDS and where possible estimate their statistical properties. We use numerical and approximate analytic methods to estimate the combined impact of these errors on HIV/AIDS estimates. Heuristic rules are then derived to produce plausible bounds about these estimates for countries with different types of epidemic and different qualities of surveillance system. RESULTS: Although 95% confidence intervals (CIs) can be estimated for some sources of error, the sizes of other sources of error must be based on expert judgment. We therefore produce plausible bounds about HIV/AIDS estimates rather than statistical CIs. The magnitude of these bounds depends on the stage of the epidemic and the quality and coverage of the sentinel HIV surveillance system. The bounds for adult estimates are narrower than those for children, and those for prevalence are narrower than those for new infections. CONCLUSIONS: This paper presents a first attempt at a rigorous description of the errors associated with estimation of global statistics of an infectious disease. The proposed methods work well in countries with generalised epidemics (>1% adult HIV prevalence) where the quality of surveillance is good. Although methods have also been derived for countries with low level or concentrated epidemics, more data on the biases in the estimation process are required.

Acquired Immunodeficiency Syndrome↗
PubMed2000

AIDS in a new millennium.

As we enter the new millennium the world is still facing the challenge of responding to the AIDS pandemic. A new report from the Joint United Nations Programme on HIV/AIDS presents the latest statistics on prevalence, spread, and impact of the disease. In their Perspective, Schwartländer and his colleagues discuss the newly released statistics and the strategies needed to combat the further spread of HIV/AIDS and to reduce prevalence in the most severely affected countries.

Acquired Immunodeficiency Syndrome↗
PubMed2000

Gonorrhea in male adolescents and young adults in Newark, New Jersey: implications of risk factors and patient preferences for prevention strategies.

BACKGROUND: Although the national rate of gonorrhea declined 68% from 1975 to 1995, rates remain high in many inner-city areas. In 1995, the gonorrhea rate in Newark, NJ, was five times the US rate. OBJECTIVE: To determine factors associated with acquisition of gonorrhea by men in Newark. STUDY DESIGN: A case-control study conducted at the sexually transmitted disease (STD) clinic in Newark, comparing males 15 to 29 years with culture-confirmed gonorrhea to controls with no STD. RESULTS: Compared with controls, males with gonorrhea more frequently reported at least 1 casual sex partner within the preceding month (adjusted odds ratio [OR], 3.2; 95% CI, 1.8-5.7), sex after using marijuana during the preceding month (OR, 2.4; 95% CI, 1.1-5.3), and a history of incarceration (OR, 2.1; 95% CI, 1.2-3.7). Of males with casual partners, having a new casual sexual relationship (onset within the past month) was particularly risky for gonorrhea (OR, 3.9; 95% CI, 1.2-12.7). Incorrect condom use was highly prevalent for both cases and controls. Many persons with gonorrhea reported that they were not willing to consistently use condoms or to have only one partner. CONCLUSIONS: Sex with casual partners is associated with gonorrhea in males, and may be a difficult practice to change. Condoms are often used incorrectly, if at all, in this population. Prevention strategies, in addition to the promotion of condom use and monogamy, may be necessary.

Adolescent↗
PubMedDate not supplied

Chlamydia trachomatis, infertility, and population growth in sub-Saharan Africa.

In sub-Saharan Africa, Neisseria gonorrhoeae and Chlamydia trachomatis are common infections. These pathogens are also the major causes of post-salpingitis tubal infertility, and infertility is a frequent problem in this region. A mathematical model, recently devised to estimate the effect of gonococcal infection on population growth, was used to estimate the potential effect of chlamydial infection on population growth. The model predictions for chlamydial infection were compared with those previously reported for gonococcal infection. The model predicts that both infections may be exerting severe effects on population growth at realistic prevalence rates of infection. The model also predicts that N. gonorrhoeae produces a steeper reduction in population growth than does C. trachomatis because its transmission dynamics result in a higher force of infection (incidence rate) at any given prevalence of infection. Large scale changes in the epidemiology of these infections can be expected to occur in sub-Saharan Africa because of improved sexually transmitted disease (STD) diagnosis and treatment services as a component of AIDS prevention. Changes in the epidemiology of gonococcal and chlamydial infection are predicted to result in accelerated population growth unless STD control programs are linked to effective contraception programs.

Africa↗