Indeterminate western blot patterns in a cohort of individuals at high risk for human immunodeficiency virus (HIV-1) exposure

Screening for human immunodeficiency virus using a newly developed fourth generation lateral flow immunochromatography assay

BACKGROUND

High sensitivity for detection of HIV-1 p24 antigen allows for early detection of primary HIV-1 infections.

OBJECTIVES

To evaluate the detection sensitivity and specificity of the Daina Screen® HIV Combo assay using clinical specimens in Japan where the pretest probability (prevalence) is low.

STUDY DESIGN

We screened 17,373 preoperative outpatient blood samples using 4^th generation lateral flow immunochromatography Daina Screen® HIV Combo assay for simultaneously detecting anti-HIV-1/2 and HIV-1 p24 antigen.

RESULTS

Of the samples tested, 24 were positive for HIV-1 p24 antigen and 49 for HIV-1/2 antibody. Of the 49 samples, 36 were WB and HIV-1 RNA negative, 10 were WB and HIV-1 RNA positive, and 3 were WB positive, HIV-1 RNA negative, and in-house HIV-1 proviral DNA positive. RT-PCR revealed that of the 24 samples that were p24 antigen positive, one sample was HIV-1 RNA positive, which was reconfirmed using an in-house HIV-1 provirus DNA assay. From the 17,300 HIV-1 p24 antigen and anti-HIV-1/2 negative samples, pools containing 10 negative samples each were tested for HIV-1 by RT-PCR; all results were negative.

CONCLUSION

The Daina Screen® HIV Combo assay had a sensitivity and specificity of 100% and 99.7%, respectively, which sufficiently detected HIV infection in the cohort.

Prevalence and risk behaviour for human immunodeficiency virus 1 infection in Marajó Island, Northern Brazil

BACKGROUND

Human immunodeficiency virus 1 (HIV-1) infection is a global public health problem, but, so far, there is no published information regarding the epidemiology of HIV-1 in Marajó Archipelago (Pará, Brazil).

AIM

The present study reports the occurrence of infection by HIV-1 in four municipalities of the Marajó Island, Pará, Brazil.

SUBJECTS AND METHODS

A total of 1877 samples were collected from volunteer blood donors (1296 women and 551 men) living in the municipalities of Anajás, Chaves, Portel and São Sebastião da Boa Vista. Information about risk behaviour assessment was obtained from a questionnaire. Plasma samples were tested for the presence of anti-HIV antibodies using serological tests. The infection was confirmed by nucleic acid amplification assays.

RESULTS

Twelve samples were seropositive for HIV by ELISA. Western blot analysis showed four positive samples, eight indeterminate patterns and one found to be negative. Molecular analysis revealed three positive samples. Risk factors for HIV-1 infection included absence of condoms during sexual intercourse (41.3%, São Sebastião da Boa Vista), use of illicit drugs (5.8%, Anajás) and early initiation of sexual activities, from 10-15 years (30.7%).

CONCLUSION

Although the study indicates a low HIV-1 prevalence in Marajó Island, some factors may increase the risk for HIV-1 and these include early sexual initiation, unprotected sexual intercourse and the use of illicit drugs.

HIV diagnosis and testing: what every healthcare professional can do (and why they should)

Over the last thirty years, the human immunodeficiency virus (HIV) epidemic has matured. In the United States, HIV has changed from an explosive outbreak to an endemic disease; currently, an estimated 1.1 million people are infected with HIV, including a substantial number who are unaware of their status. With recent findings demonstrating the high transmissibility of HIV early in infection, and the potential benefit of early initiation of treatment, it is essential to identify as many infected individuals as possible. The Centers for Disease Control and Prevention (CDC) has expanded HIV testing to include any healthcare setting, including dental offices. Testing advances, including oral testing, have reduced the window period of HIV infection. Dental care represents a key, reliable, independent, and confidential link between the healthcare system and the general population that has been under-utilized in the effort to control the HIV epidemic. HIV testing is straightforward, and knowledge of the types of testing will afford dentists an important opportunity to help advance and preserve the health of their patients and to promote the public health of their community. Here, we review the basics of HIV testing and discuss new changes in the approach to HIV diagnostics.

The epidemiology and transmission of AIDS: a hypothesis linking behavioural and biological determinants to time, person and place

Epidemiologically, the Acquired Immune Deficiency Syndrome, AIDS, is transmitted and distributed in the USA and Europe almost entirely in well-defined subsets of populations engaging in, or subjected to, the effects of behaviours which carry high risks of genital and systemic infections. The persons predominantly affected are those engaging in promiscuous homosexual and bisexual activity, regular use of addictive drugs, and their sexual and recreational partners. In such persons and in subsets of populations with corresponding life-styles, the risk of AIDS increases by orders of magnitude. Because of continuity of risk behaviour and of associated indicator infections, the incidence of AIDS over 3-5 year periods is predictable to within 10% of actual totals of registered cases in the USA and UK. Secondary transmission of AIDS beyond these groups is minimal or, in many locations, absent. There is no indication of appreciable spread by heterosexual transmission to the general population. The Human Immunodeficiency Virus, HIV, is transmissible to some extent in general populations, and more so among promiscuous persons. It may cause viraemia, lymphadenopathy and latent infection (HIV disease) in anyone. In persons engaging in risk behaviours which themselves alter or suppress immune responses, it can interact with MHC, antibodies to other organisms and to semen, and other allogenic antigens to initiate a programmed death of CD4 lymphocytes and other defensive cells, as in graft-host rejections. This occurs also in haemophiliacs receiving transfusions of blood products, and is more pronounced in persons with reactive HLA haplotypes. The susceptibility of particular subsets of populations to AIDS is thereby largely explained. But these changes occur in the absence of HIV, and so do Kaposi's sarcoma, lymphadenopathies and opportunistic infections which are regarded as main indicators of AIDS. The hypothesis that HIV-1 can do all this by itself and thereby cause AIDS is falsifiable on biological as well as epidemiological grounds. An alternative hypothesis is proposed, linking the incidence of AIDS to the evolution of contemporary risk behaviour in particular communities and locations in the USA, UK and probably in most of Europe. It does not pretend to explain the reported incidence of AIDS in Africa and other developing regions where data are insufficient to provide validation of the pattern of disease and contributory variables. The immediate, practical implication of this alternative hypothesis is that existing programmes for the control of AIDS are wrongly orientated, extremely wasteful of effort and expenditure, and in some respects harmful.

Molecular methods: applications for clinical infectious diseases

The application of molecular biology to microbiology has led to a surge of new information about most infectious microorganisms, the pathogenesis of the infections they cause, and the specific microbial antigens involved in the immune response to these infections. The simultaneous application of the same techniques to diagnosis and epidemiology has also shown great promise, but these developments have not yet had a major effect on the routine practice of medicine. For some purposes, direct probe tests perform as well as other available methods. However, for most infections, these methods have not been proven sufficiently sensitive. The latest generation of highly sensitive diagnostics based on the polymerase chain reaction will overcome this technical obstacle and may revolutionize the management of many infections. Difficulties inherent in performing these tests will require special procedures and training in clinical laboratories to ensure that they are performed reliably. Nucleic acid-based methods for epidemiologic typing of microorganisms and for identification of noncultivatable pathogens are particularly useful for analysis of poorly cultivatable, dangerous, or otherwise untypeable microorganisms.