Bridging the Gap: Conference Record [Abstract book, International Conference on AIDS (12th: 1998: Geneva, Switzerland)]

106 Abstracts 13104-13108

12th World AIDS Conference

S13104 Recency in regional HIV spread progression: 1997
incidence over 1997 prevalence
Roger-Paul Bernard', U. Zellweger2, J. Wang2, B. Somaini2. 'AIDS Feedback
(AF), Geneva, GE; 21SPMZ, University of ZOrich, ZH, Switzerland
Objective: To translate the end-1997 WHO/UNAIDS best estimates of regional
HIV prevalence & incidence into a world gradient of HIV progression. To create interdisciplinary instant access to the current realities by modern display
methodology.
Design: Global analytical integration (GLANIN) of best WHO/UNAIDS 'World
AIDS DAY 1997' estimates of HIV prevalence (end-1997) & incidence (1997).
Presentation of outcome as numerator analysis (Panel A) & in DEM-EPI Display
(Panel B), both giving relative magnitudes of HIV problem across the 10 regions
(surface/height).
Materials and Methods: The sole source of data is the WHO/UNAIDS 'World
AIDS DAY 1997' release of best estimates by region (n = 10). The '16-slide
series' for teaching was reviewed and slides 1&2 (prevalence) and 7&8 (incidence) submitted to analysis and synthesis. New HIV infections in 1997 were
given as the proportion of the end-1997 HIV prevalence; then ranked across the
ten world regions from high to low to generate a world gradient spanning from
66.7% (Eastern Europe & Central Asia) down to 5.0% (Australia & New Zealand).
For interdisciplinary and intersystems understanding of recent dynamics in HIV
spread, in the context of the relative magnitude of the problem, two graphical
presentations are to be developed in strict numerator analysis (Panel A) & in
DEM-EPI display (Panel B).
Conclusions: High-low ranking of the proportion of end-1997 HIV prevalence
pertaining to 1997 infections generates ten %-levels-compacted further into 5
groups (A-E) of HIV spread progression. Eastern Europe (& Central Asia) has
the most dynamic spread & East Asia/Pacific (minus Japan) vs 'near-arrest' in
further spread in the industrialized world (E + Japan). Two display panels give
details.
13105 HIV reactive patients with follow up in an ambulatory care
center
Marcelo Laurido', Edgardo B.E. Bottaro2, Diego C.D. Cajafa2, Gabriela
B.G. Bugarin2, Rosa B.R. Bologna2, Isabel C.I. Cassetti2. 'Peru 1515; 2 Hellios
Salud, Buenos Aires, Argentina
We performed a cross sectional study on a population of HIV (+) patients (pt)
that started their follow up between 9-1-97 and 12-31-97, in an ambulatory care
center whose health insurance is HMO like.
Objective: to assess demographic characteristics, disease stage, opportunistic
diseases (OD) and antiretroviral treatment.
Results: There were 443 pts enrolled: 430 adults and 13 pediatrics, a. Adults:
137 female (32%) and 293 male (68%). Mean age was 32 years old (19-60),
median 31. Ninety four percent (403 pt) belonged to Buenos Aires metropolitan
area. The lapse of time between HIV diagnosis and first consultation was established in 421 pt. This period was less than 5 years in 76%. We could establish the
disease stage in 405 pt; 199 of them met the CDC criteria for AIDS (49.1%). On
average, CD4+ cell count was 278/mm3 (7-1,800) -median 231/mm3- and viral
load was 107,267 RNA-copies/ml of plasma (<400-1,500,000) -median 24,930-.
We described 291 episodes of OD in 195 pt. Most frequent ODs were: thrush (72),
PCP (47), TB (28), herpes zoster (26) and CMV retinitis (16). There were 295 pts
with a mean previous treatment period of 5 months (1-24),182 of them were on
a combined therapy with protease inhibitors (ZDV-3TC-IDV 61, d4T-3TC-IDV 47,
ZDV-ddl-IDV 16), 66 had treatment with two analogue nucleosides (ZDV-ddl 33)
and 47 had combined therapy with NVP. There were 115 pts with no treatment, 21
of them recently diagnosed. b. Pediatrics: 5 female (38.5%) and 8 male (61.5%).
Mean age was 51 months (1-120). All of them belonged to metropolitan area and
had connate infection. Five pt met the CDC criteria for AIDS (38.5%). On average, CD4+ cell count was 604/mm3 (59-2,405) -median 357/mm3- and viral load
was 26,133 RNA-copies/ml of plasma (<400-180,000) -median 8,550-. There
were 5 ODs: 4 recurrent bacterial infections and 1 TB. Ten pts had antiretroviral
treatment, 3 of them had combined therapy with RTV and 7 had two analogue
nucleosides (ZDV-ddl, ZDV-3TC and d4T-3TC).
Conclusion: The major findings in our study were the advanced stage of the
disease, the high number of untreated pts and the lack of a uniform criteria
for antiretroviral therapy. The reason for these findings is that our patients had
been referred to our institution from different medical centers. Now, they have the
chance to be followed up with a unique medical criteria. In a second phase, we
will assess the impact of our intervention.
13106 7-year trends in adult HIV-1 prevalence, incidence and
mortality in a rural Ugandan population
Anatoli Kamali, L.M. Carpenter, A. Ruberantwari, A. Ojwiya, J.A.G. Whitworth.
MRC Programme On AIDS, UVRI PO. Box 49, Entebre, Uganda
Background: To describe trends in HIV-1 prevalence, incidence and mortality in

a Ugandan adult general population cohort.
Methods: Annual censuses and serosurveys were carried out of all adults (13+
years) residing in 15 neighbouring villages in SW Uganda between 1989 and
1997. At each survey round sera were tested for HIV-1 antibodies using two EIAs,
confirmed by Western Blot when necessary, to identify prevalent and incident
cases. Deaths were notified at census and through a monthly vital registration
system. Rates of disease occurrence and death are shown per 1000 person-years

(PY) with 95% confidence intervals [95%CI]. P-values are for two-sided tests for
trend across all years unless stated otherwise.
Results: At each round an average of 5500 adults were resident, of whom 65%
were bled. Overall HIV-1 prevalence declined from 8.1% [7.3-9.0] at round 1 to
5.8% [5.0-6.6] at round 8 (P < 0.001). Prevalence declined significantly among
men aged 20-24 (11.7% to 2.9%; P < 0.001) and 25-34 (17.8% to 12.0%; P
= 0.01) and among women aged 13-19 (4.4% to 1.5%; P = 0.006) and 20-24
(20.9% to 13.2%; P = 0.002). No significant decline in prevalence was seen in
other age-sex groups (P for trend >0.05). Overall incidence declined from 7.7
per 1000 PY [4.9-12.3] in 1990 to 4.2 per 1000 PY [2.4-7.2] in 1996 but this
trend was not statistically significant (P = 0.2). There were no significant trends
in age-sex specific incidence rates (P > 0.4) but among women 13-34 years
incidence peaked at 17.7 per 1000 PY in 1993 and fell in subsequent years (P for
unequal rates = 0.002). Age-standardized death rates over the whole period of
follow-up were 9.9 per 1,000 PY among HIV-negative and 113 per 1000 PY among
HIV-positive adults. The percentage of mortality in the population attributable to
HIV fell from 81% [34-94] in 1990 to 58% [4-81] in 1996 among adults aged
13-35 (P = 0.4), and from 35% [0-75] in 1990 to 29% [0-54] in 1996 among
those aged 35+ but neither decline was statistically significant (P > 0.2).
Conclusions: These are the first cohort data to report a long-term statistically
significant decline in overall HIV prevalence in a general population in rural Africa.
The observed decline in incidence was not statistically significant, but the power
to detect a trend was low. HIV continues to exert a particularly heavy toll on death
rates among young adults in this population.
13107. Serial human passage of SIV and the origin of HIV-1 and
HIV-2 in Africa: The role of unsterile injections in the
period 1950 to 1970
Preston Marx', P. Alcabes2, E. Drucker3. 1455 First Avene 7th Floor New York
NY 10016; 2New York University Medical Center New York NY; 3Albert Einstein
College of Medicine New York NY USA
Objectives: Phylogenetic and geographical studies point to the occurrence of
SIV in Africa for thousands of years without HIV's emergence. Our objective was
to identify a modern biologically plausible event that accounted for the virtually
simultaneous appearance, in the mid 20th century, of several different strains of
HIV at multiple locations in Africa.
Design: Stochastic modeling of the transmission and mutational probabilities
for human SIV infection was calculated in relation to the introduction of unsterile
injections in Africa in the period 1950-1970.
Methods: Lentivirus-mutational rates were applied to SIV to estimate a minimum number of serial human passages of SIV needed to produce mutation of
SIV to HIV. The prevalence and viremic window of SIV infection in humans, and
the number of unsterile injections in Western and Central Africa in this period
were used to model the probability of such passages.
Results: Under optimal conditions for selection of variants, and with a window
of active SIV replication of 14-35 days, the accumulation of mutations consistent
with the emergence of HIV from SIV was estimated to occur with a probability
of <1% during a single acute human SIV infection. We calculated that 7 serial
human passages (lower boundary of 90% confidence interval = 2) of SW would be
needed to allow the accumulation of a minimum of mutations for the emergence
of HIV from SIV. The prevalence of SIV-like infections in West Africa was 0.02% to
1.00%. Injections of newly available drugs in Western and Central Africa, between
1950-1970 account for 15-30 million unsterile injections, providing opportunity
for significant numbers of serial SIV human passages to occur.
Conclusions: SIV existed in Africa long before the modern AIDS epidemic,
yet HIV did not emerge because multiple human to human transmissions were
necessary for an adequate number of mutations to accumulate in a single SIV
genome. The introduction of injectable medications and millions of unsterile injections in Africa, after World War II, provided the biological mechanism for HIV
to mutate from SIV.
13108 Incidence of HIV-1 infection and associated risk factors in
a cohort of police officers in Dar es Salaam, Tanzania
Kisali Pallangyo1, M. Baraki', E. Lyamuyal, F. Mhalu', N. Pallangyo'1,
E. Sandstrbm2, G. Biberfeld2. 1Muhimbili Medical Centre, Dar-Es Salaam,
Tanzania; 2Sbder Hospital, Stockholm; Karolinska Institute, Stockholm, Sweden
Objective: To determine the HIV-1 incidence and associated risk factors among
police officers in Dar es Salaam.
Methods: Beginning February 1994, police officers (POs) were recruited into
an open cohort to determine if they were a suitable population for HIV vaccine
trials. A standardized questionnaire was completed at enrolment and subsequent
scheduled examination visits. HIV antibodies were determined by two enzyme
linked immunosorbent assays (ELISA) (Enzygnost anti-HIV-1/2 Plus and Wellcozyme recombinant anti HIV-1). Samples which were repeatedly discordant were
tested by a Western blot assay.
Results: As of 31 December 1997, 2863 POs had been recruited. At base
line examination 348/2534 (13.7%) males compared to 61/329 (18.5%) females
tested positive for HIV-1 antibodies (p = 0.018). During a period of three months
preceding scheduled examinations 550/2534 (21.7%) men and 76/329 (23.1%)
women had had extramarital sex. Condoms were not used by 485/550 (88.2%) of
these men and 72/76 (94.7%) of these women. Blood samples for HIV incidence
studies were obtained from 1526 males and 200 females. The 1526 males HIV
seronegative at base line examination were observed for 2454 person years