Re: Re: Re: Re: Request for Peter Flegg 19 November 2004
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Nicholas Bennett,
Infectious Disease Postdoc/Clinician
Department of Pediatrics, University Hospital, Syracuse NY

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Re: Re: Re: Re: Re: Request for Peter Flegg

Mark Bartlett says that he questions whether the human assumtions were wrong, rather than the virological ones.

He's right in that I meant behaviour, but I also meant the status quo at the time. I think the homosexual cases were expected to be the tip of the iceberg and that considerable (sub-clinical) cross-over to the heterosexual population had already occured. Indeed, heterosexual and vertical spread from infected haemohiliacs, IV drug abusers and bisexual men (okay, maybe not vertical spread from these guys!) did result in transmissions that were part of the move away from a lifestyle cause and the consideration of an infectious agent, but these were not of the magnitude expected. It must be remembered that at the time the time to progress to AIDS wasn't known and neither was the transmission rate. Early estimations were a relatively easy transmission with a 6 month progression to AIDS! When serological testing was more widely available then more accurate estimations of progression became possible (around 8-10 years).

I would say that sexual attitudes _have_ changed, but perhaps more towards a principle of assumption and discrimination rather than overall improvements in sexual health. To me there is no paradox in sexual inequality in the west when you consider what the sexual orientation of the people are. Most cases in the west are men, most of those men acquired it through homosexual sex. In some ways, an explosion of cases in women would need to be explained more, if they didn't have risk factors such as exposure to shared needles or an infected partner!

Microbes do indeed discriminate based on geographical location. Coming to the US from the UK such "tropical" rarities as Lyme Disease are suddenly considered core knowledge. Conversely moving away from a tertiary referral hospital servicing a well-travelled population has meant that the numbers of malaria cases have dropped. HIV itself is three times more common in the US than in the UK. As regards oppotunistic infections, TB is unusual in the US but quite common even among the immune-competant in some places in Africa. Since each OI will become a risk at different levels of immune function, it doesn't seem too surprising that where TB is common it will be seen first. Where TB is rare, the immune system can decline further before other infections (e.g. PCP) are noticed. KS, being due to a sexually transmitted infection of HHV8, is also associated with certain risk groups and areas.

The other thing to bear in mind is that the broad brush strokes often spoken of in these discussions don't reveal the details: the same highly unusual OIs do indeed appear in African AIDS as well as western AIDS, but you have to plough through case reports to find the cryptococcal meningitides and toxoplasmosis, Cryptosporidium and Isopora belli. Certain diseases are rarer (PCP and MAC) but these are associated with profound immune dysfunction and it's not inconsistent to imagine that exposure to a wide variety of other OIs may well lead to death prior to the appearance of PCP or MAC.

I note Mr Bartlett's comment on the politicisation of AIDS with interest. As a lethal STD it has indeed captured the political arena, but I'd not previously considered that to be anything more than a hindrance to free research and sensible public health measures. If in his mind at least the overlap is a part of the rationale behind his skepticism, then I find that both unfortunate, and understandable. Others here have already spoken of the redirection of research funds away from other diseases, and the problems of discrimination and racial attitudes, and of course there are other implications such as the barring of HIV-positive people from entering the US (with certain exceptions) and the Ryan White CARE act which is aimed at providing US Government money to assist AIDS patients. All of this, in its own way, is both commendable and deplorable, depending on your point of view.

Personally, I'd rather pretend the politics didn't exist...but I don't think it's going to go away.

Nick Bennett njb35@cantab.net

Competing interests: None declared