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

12th World AIDS Conference

Abstracts 13109-13113 107

(PYAR) during which time 50 HIV-1 seroconverted compared to 10 among 200
women observed for 346 PYAR. Over all the HIV incidence was 21.4/1000 PYAR;
and by sex 20.4 and 28.9 for males and females respectively (p = 0.21). The HIV
incidence per 1000 PYAR was 38.2 among females aged 20-29 years compared
to 18.3 among males of the same age bracket (p = 0.12). Among unmarried
officers the HIV incidence per 1000 PYAR was 66.7 for women and 18.7 for men
(p = 0.01).
Conclusion: (1) There is high risk sexual practice and low condom use among
POs.
(2) Baseline HIV-1 prevalence was significantly higher among females compared to males.
(3) The HIV-1 incidence was generally high especially among single women.
(4) POs are a suitable population for HIV vaccine trials.
431*/13109 The molecular epidemiology of HIV-1 in Uganda
Robert Downing1, B. Biryahwaho1, R.A. Otten2, M.A. Rayfield2, D. Pieniazek2
D. HU3, S.D.K. Sempala1. 1CDC/UVRI Research Collaboration, Uganda Virus
Research Institute, Entebbe, Uganda; 2Retrovirus Diseases, NCID, CDC Atlanta,
GA; 3lnternational Activity, NCHSTFP CDC Atlanta, GA, USA
Background: In an earlier study in 1994/5, 57.4% of the 594 HIV infections
which could be typed were subtype "A", 42.1% were "D" and 0.5% were "C". No
significant clinical or demographic differences between subtypes were found.
Objectives: The purpose of the present study was to determine the proportional
distribution of HIV-1 subtypes in Uganda in 1996.
Methods: During 1996, blood specimens from 825 seropositive and 147 high-risk seronegative or indeterminate subjects, collected at 14 sites across the
country, were screened for the HIV genome by probe hybridization (PH) using
primers and probes from the protease gene. Genome-positive specimens were
sub-typed by protease-RFLP analysis of Alu I, Bcl I and Sca I restriction digest
patterns.
Results: Of the 825 seropositive specimens, subtype was determined for 761
(92.2%) by protease-RFLP analysis. The overall proportion of sub-types was
53.9% "A" (388), 43.8% "D" (315), 1.7% "C" (12), and 0.7% "F" (5). In addition,
41 specimens gave RFLP patterns consistent with mixed infections of "A" with
"D" or "C" with "D". Only 1 of the seronegative or indeterminate specimens was
positive for the genome by PH; RFLP analysis of this specimen suggested that
both subtypes "A" and "D" were present. Additional testing was done on the
64 specimens from seropositive subjects which could not be amplified in the
protease gene; 10 specimens could not be amplified using "housekeeping" genes
and were discarded as being of poor quality; 19 specimens were typed by PH in
the env-C2V3 region (16 were subtype "A" and 3 reacted with both "A" and "D"
probes). None of the remaining 35 specimens could be amplified with either HIV-1
group O-specific or HIV-2-specific protease primers nor with HIV-1-specific integrase primers but 6/35 specimens were amplified using HIV-1 group M-specific
gag primers.
Conclusions: More subtype "C" infections were found in 1996 than in 1994/5
and, for the first time in Uganda, there was a suggestion that subtype "F" might
be present. However, since sampling was more extensive in 1996, these findings
do not necessarily indicate a change in subtype distribution. Moreover, specimens designated as subtypes "C" or "F" or as "mixed infections" will require
nucleotide sequencing for confirmation. Despite a broader sampling in 1996, the
overall proportional distribution of HIV-1 subtypes was consistent with that found
previously.
S13110 Genetic diversity of HIV-1 in Tanzania: Use of
heteroduplex mobility assay (HMA) for HIV-1 subtyping
Eligius Lyamuya1, U. Bredberg-RAden2, P. Kalliriorinne2,
E. Olausson-Hansson2, J. Albert2, F. Mhalu1, G. Biberfeld3. 1Muhimbili Medical
Center, PO. Box 65001, Dar Es Salaam, Tanzania; 2Swedish Inst. for Infectious
DisControl, Stockholm; 3Karolinska Institute, Stockholm, Sweden
Objectives: To determine the distribution of HIV-1 subtypes in Tanzania by
heteroduplex mobility assay (HMA) on plasma samples
Methods: Blood samples were collected from HIV-1 seropositive asymptomatic
pregnant women in Dar es Salaam (in 1995 and 1997) and Kagera (in 1997),
and from recent seroconverters among police officers in Dar es Salaam (between
1996-1997)). RNA was extracted from plasma by using the QIAamp Viral RNA
kit (QUIAGEN). The RNA was reverse transcribed into cDNA using primer ED12.
A 700bp long fragment of the gp120 V3 to V5 region was amplified in a nested
PCR. The HMA was performed as described by Delwart et al. (PCR Methods
Applic. 1995, 4: S202-216). DNA material from PBMCs from some of these
samples were analyzed by direct sequencing of the V3 region using an automatic
sequence apparatus (ALF, Pharmacia).
Results: About 75% of the plasma samples tested could be successfully PCR
amplified with the HMA primers for the 700 bp fragment. Of the subtyped samples
from pregnant women in Dar es Salaam, 37% (33/90) were subtype A, 37%
(33/90) were subtype C and 27% (24/90) were subtype D. For the Kagera samples 41% (7/17) were subtype A, 18% (3/17) subtype C and 41% (7/17) subtype

D. Among recent seroconverters in the police officers cohort HIV-1 subtypes A,
C and D were detected in 50% (9/18), 22% (4/18) and 28% (5/18) of the tested
samples respectively. There was a good correlation between the results of HMA
and DNA sequencing.
Conclusion: HIV-1 subtypes A, C and D are all prevalent in the Dar es Salaam
as well as Kagera areas of Tanzania. The HMA method is a possible alterna
tive for determination of HIV-1 subtypes, especially in laboratories with limited
sequencing facilities.
13111 Prevalence of HIV and syphilis infections among
pregnant women attending urban antenatal clinics in C6te
d'lvoire, 1997
Sidibe Kassim1, S.Z. Wiktor1, C. Maurice1, A. Lawson2, I.M. Coulibaly3. 101 BP
1712 Abidjan 01, Project Retro-CI, Abidjan; National AIDS/STD/TB Control
Program, Adibjan; 2UNIAIDS, Adibjan, Cote d'lvoire; 3Centers for Disease
Control Prevention, Atlanta, USA
Objective: To assess the prevalence of HIV and syphilis infections among pregnant women attending antenatal clinics in the ten largest cities of C6te d'lvoire.
Methods: In 1997, as part of a nationwide HIV serosurveillance program,
anonymous unlinked HIV testing was carried out in the capital cities of all ten
regions of C6te d'voire. Demographic data and aliquots of sera collected for
syphilis testing were obtained from approximatively 300 consecutive first-time
clinic attenders. Sera were tested for syphilis antibodies on-site, and after the
women had received their syphilis result, anonymous unlinked serum samples
were sent to a central laboratory and were screened for HIV antibodies by
two mixed enzyme immunoassays (EIA); reactive samples were confirmed and
serotyped by a combination of monospecific EIAs or Western blot. Serum samples
were retested for syphilis antibodies by TPHA and RPR.
Results: 3043 women were tested for HIV antibodies and syphilis results were
available for 1635 women. 82% of these women were born in C6te d'lvoire and
their median age was 24 years (range 13-57). 87% of women were living in stable
partnerships and 66% had no formal education. Median gestational age was five
months. Prevalence of HIV infection was 9.0% (7.8% HIV-1; 0.8% HIV-2; 0.4%
dually reactive) and ranged from 5.9% to 13.3% by city. Prevalence of syphilis
infection was 1.3% and ranged from 0.0% to 2.4%. In multivariate analysis, factors
associated with HIV infection were: birth in C6te d'lvoire (odds ratio [OR] 1.6; 95%
confidence interval [Cl] 1.04-2.4), age group 20-29 years (OR 2; Cl 1.4-2.7),
single marital status (OR 2.2; CI 1.5-3) and first trimester of pregnancy (OR 1.6;
Cl 1.1-2.3). Syphilis infection was not associated with HIV infection (OR 1.0; Cl
0.1-4.2).
Conclusion: An HIV and syphilis sentinel surveillance program based in public
antenatal clinics is feasible in C6te d'lvoire. Prevalence of HIV infection among
pregnant women varies by geographic region and is greater than 5% throughout
the country, while prevalence of syphilis is less than 2.5%. Annual serosurveys in
this population will enable the Ivorian Ministry of Health to monitor both national
HIV and syphilis trends and the efficacy of HIV and STD prevention programs.
S13112 Characterization of HIV-1 subtypes in Senegal by
heteroduplex mobility assay (HMA)
Ndeye Coumba Toure Kane1, D. Delphine Sauvageot3, M.A. Faye2, A. Gaye
Diallo1, M. Peeters3, S. Mboup'. 1Laboratoire Bacteriologie Virologie Avenue
Pasteur BP7325 Dakar; 2Universite Cheikh Anta Diop, Dakar; 3Laboratoire
Retrovirus, Hontpellier, Senegal
Objectives: To determine the HIV 1 genotypes present in senegal
To evaluate the local diversity and the presence of possible recombinant or
new clades.
Methods: Since January 1997 247 HIV1 patients attending one of the three
hospitals in Dakar were blood sampled and peripheral blood mononuclear cells
(PBMC) were separeted by Ficoll Hypaque gradient. DNA were extracted from
PBMC by Isoquick Kit. DNA were amplified for env gene and subtyping was done
by HMA using plasmids from typed references strains (A-H). All HMA tests were
performed in Dakar. A subset of DNA were sequenced in France (Montpellier)
where all inderminated samples by HMA were characterized by sequence for
env gene through the V3-V5 region and recombinants were checked also by
sequence on gag gene for the P24 region.
Results: A total of 247 subtypes determinations were done by HMA and 225
were classified and 22 remained inderminated. Among the 225,195 were typed
as clade A, 13 as clade C, 11 as clade B, 4 as clade D and 2 as clade G. Among
the 22 indeterminated 15 were sequenced: one was typed as clade D, one also
as clade C another as clade F and the twelve as clade A. For recombination
among 20 samples sequenced 4 were recombinants one A/H One C/A two A/G
and 7 remaing inderminated will be sequenced further.
Conclusion: HMA allowed us to genotype 92% of our samples. We observed
a local diversity of HIV1 genotypes and a predominance of clade A 86%. Gag
sequence showed us 20% of circulating recombinant viruses in our study. HMA
is the most adaptable genotyping technique for developping countries.
i13113 Age specific change of serotype prevalence among
asymptomatic pregnant women & blood donors in
Tanzania
Michel Hoelscher1, D. Eimannsberger1, R. Cheingsong-Popov2,

B. Jordan-Harder', H. Nkwera3, L. Guertler4, F. Von Sonnenburg1. 1Georgenstr.
5, LMU-Tropical Institut; 4LMU-Max Von Pettenkofer Institut, Munich, Germany;
2JMerial College of Medicine, London, UK; 3Mbeya AIDS Control Programme,
Mbeya, Tanzania
Objectives: To determine changes of subtype prevalence over time and among
different population and groups in Mbeya Region, Southwest Tanzania since 1989.