Infectious Disease Postdoc/Clinician
Department of Pediatrics, University Hospital, Syracuse NY
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I admit that the situation in Africa (and other developing world countries) is different: but in two very opposing ways. On one hand the rate of infection is far higher than in the developed world. Even using the more stringent diagnostic criteria which should reduce or remove false positive results we still find rates of up to 30% in some cohorts. Even a rate of 3% would be an order of magnitude higher than in the US.
On the other hand we do see the use of less stringent tests, due to the limitations of time, space, technology and sadly money.
Of course the two will to some degree balance out: the positive predictive value will be lessened by the use of less accurate tests, but at the same time will be increased by the increased rate of infection in the population. As to how well this holds true in terms of real numbers...I don't think anyone really knows.
The point I was hoping to make was actually less pronounced in my final draft: that the diagnosis of HIV is hugely important. The clinical picture is taken into account above and beyond the test results, the same as any other test in medicine. The docs do not rely on one methodology or another, and then blindly prescribe antiretrovirals to be eaten en masse.
HIV viral culture isn't all that hard, just time consuming. A decade or more ago culture systems were developed that increased the detection rate of HIV vastly. Early reports of "HIV in 50-60% of AIDS cases" were replaced by "HIV found in all AIDS cases, with several thousand tissue- culture infective doses per ml". Finding culturable HIV from the seropositive but asymptomatic cases is one of the many nails in the dissident coffin.
The opportunistic infection argument is not a new one: it was proposed by Duesberg at the very begining of the epidemic. In a way, it is probably true: certainly as the immune system wanes in the latter part of pre-AIDS HIV replication goes out of control, with rapidly increasing viral loads. But the fact is that HIV infection nearly always precedes the immune decline. Some of the cohort studies I referenced previously document seroconversion and then CD4 cell declines in a striking and horrifying manner. Seeing this kind of immune decline from the pre- treatment era is like watching a train-wreck in slow motion: there was simply nothing that could be done.
The arguments for "continual immune attack" don't really bear up. I've seen little evidence for the kind of immune decline seen in HIV being due to anything else: both in terms of clinical picture and lab markers. In at least one cohort in fact, continual exposure to HIV through sex acts was protective as it induced strong anti-HIV cellular responses (unusual even in infected people). Drug users may even have higher CD4 counts overall than non drug-users, once HIV serostatus is taken out of the picture . It is interesting that while medicine teaches that specific illness are more likely in certain population groups (STDs in sex workers, blood poisoning in IV drug users, TB in the homeless or crowded) no population group has historically suffered from the AIDS condition. The closest comparators are those on anti-rejection drugs or with end-stage leukaemia/lymphoma.
Even in Africa, the situation is unlike any other time except during war: young adults simply do not die at the rates they are currently, it is the young and the old.
The figures are not absurd: infection rates with CMV easily top 50% in adults, RSV seropositivity is nigh on 95% by age two. Pneumocystis is a commensal in over 90% of the adult population. Staph Aureus is found in at least 33% of the community. Remember this is an epidemic that by most measures was likely spawned in the middle of the last century, and with an average clinical latency of 10 years, combined with ignorance, denial and insufficent assistance, to find that 10-30% or so of adults are infected is perhaps surprising.
1. Kaul et al. J Immunol. 2000 Feb 1;164(3):1602-11. "HIV-1-specific mucosal CD8+ lymphocyte responses in the cervix of HIV-1-resistant prostitutes in Nairobi."
2. Ascher et al. Nature. 1993 Mar 11;362(6416):103-4. "Does drug use cause AIDS?"
Competing interests: None declared