October HIV/AIDS Public Health Journal Club

October's inter-departmental HIV/AIDS Public Health Journal Club was addressed by Drs Pravi Moodley and Raveen Parboosing, both of the Nelson R Mandela School of Medicine's Department of Virology. Dr Moodley's presentation was entitled "Structured Therapy Interruption (STI) in HIV Treatment" and Dr Parboosing's covered "HIV and Herpes Simplex".

Dr Moodley's talk took the audience through the main features of the STI debate that prevailed at the Barcelona AIDS-2002 Conference, including the viewpoints of researchers such as Franco Lori, Bruce Walker, Martin Markowitz, Mark Dybui, H. Gunthard and others. Dr Moodley noted that STI could not be regarded as a "cost-saver" in the South African context, because the therapy could not be conducted efficiently without thorough baseline testing of the quality and quantity of CD4 cells, which is an expensive process. He further noted that HIV transmission is highly likely during the phases of interruption.

Commenting on an article describing a study by Garcia et al in AIDS, June 2001, (15)9, Dr Moodley noted the plethora of viral dynamics inherent in STI therapy, with the "rebound" effect being significant e.g. the viral load emerging at much higher levels after interruption than those reflected at the point of baseline testing.

Responding to a question regarding the risk of resistance development, Dr Moodley replied that this seemed to be fairly low; some mutation had been recorded, but this would only be clinically damaging were it to occur along with other mutations and disease factors. Dr Fanny Kiepiela's current study involving STI with infants at St Mary's Hospital, Mariannhill, KwaZulu-Natal would be closely tracked in this regard.

Dr Parboosing's presentation examined the paradigm of HIV and Herpes Simplex co-infection as viewed within two contexts, those being "association" and "causation". Association involves common risk factors that are not biologically linked, while causation assumes a biological link i.e. that the HSV occurs as a result of HIV infection. Once both association and causation are apparent, "epidemiological synergy" is established. The relationship between these processes then cascades into a co-infection syndrome.

An important factor in the sub-Saharan HIV/AIDS epidemic with regard to HSV is that sexually transmitted diseases (STDs) are highly prevalent in our region; if an ulcerating STD is disrupting the patient's mucosal lining, causing an inflamed response, a perfect entry route for HIV is prepared.

Dr Parboosing then summarised the findings of the following studies:

Corey et al., JAMA 2000; 283 : 791-4 (HIV Immunosuppression and HSV replication)
Albrecht et al, J Virology 1989; 63:1861 - 1868 (Virus-to-Virus interactions : ICP4)

He presented in some detail on a landmark study conducted in South Africa by Chen et al (CDC, WITS, SAIMR: Sexually Transmitted Diseases, January 2000: "Human Immunodeficiency Virus and Genital Ulcer Disease in South Africa - The Herpetic Connection").

Dr Parboosing also compared the findings of the Mwanza study (AIDS 1997, 11: 1873-1880) with those of Rakai (AIDS 1997, 11: 1873-1880) and took the audience through research by Auvert et al (WITS, MRC[Durban], UNAIDS, CSI) on "HIV infection among youth in a South African mining town as associated with Herpes Simplex Virus-2 seropositivity and sexual behaviour" (AIDS 2001, 15: 885-898).

In closing, Dr Parboosing noted that HSV and HIV involved a lifelong co-infection synergy with both epidemiological and biological public health implications, and that since HSV was fueling the HIV/AIDS epidemic in our region, intervention strategies had to be developed to address these. He emphasised that practitioners should always take the possibility of HIV infection into account when patients presented with STDs.

Prof Jerry Coovadia further commented that there was valuable work on intervention strategies being conducted in the area of STDs and circumcision as these related to HIV infection, more especially in the social and behavioural sciences as opposed to treatment studies.

To download the PowerPoint versions of these presentations, please click on the links in the righthand column.