Age-dependent choice of sexual partners and the transmission dynamics of HIV in sub-saharan africa

A mathematical model of the transmission of H IV -1 within heterosexual populations in Sub-Saharan Africa is described and its properties analysed. The model incorporates epidemiological and demographic processes and extends previous work in this area via the inclusion of age and sex dependency in rates of sexual partner change, and sexual partner choice dependent on age. Parameter assignments are made on the basis of current data on the transmission dynamics of HIV-1 and the demography of hum an populations in Africa. Both age-dependent rates of sexual activity and the sexual contact of males with females younger than themselves act to enhance the predicted demographic impact. With realistic parameter values, the model suggests AIDS is able to reverse the sign of population growth rates from positive to negative values over a timescale of a few decades. The sensitivity of this prediction is examined in relation to changes in the pattern of sexual contact between different age classes of females and males, different patterns of change in the age-dependent rate of sexual partner change, different assumptions concerning the doubling time of the epidemic in its early stages, and the relative efficiencies of viral transmission between men and women, and vice versa. The impact AIDS is predicted to have on the number of young and elderly persons as a fraction of the number of productive adults (the dependancy ratio) is examined under various assumptions concerning the weighting to be applied to mirror the burden imposed by the care of those with AIDS. The paper includes an assessment of the influence of the timing of changes in sexual behaviour, or the promotion of the use of condoms, on the predicted course of the epidemic. The paper concludes with a discussion of data needs and the model refinements required to more accurately mirror current understanding of the epidemiology of HIV -1.

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The Role of Phylogenetics in Discerning HIV-1 Mixing among Vulnerable Populations and Geographic Regions in Sub-Saharan Africa: A Systematic Review

Viruses ◽

10.3390/v13061174 ◽

2021 ◽

Vol 13 (6) ◽

pp. 1174

Author(s):

George M. Nduva ◽

Jamirah Nazziwa ◽

Amin S. Hassan ◽

Eduard J. Sanders ◽

Joakim Esbjörnsson

Keyword(s):

Risk Group ◽

Risk Groups ◽

Phylogenetic Inference ◽

Sub Saharan Africa ◽

Transmission Dynamics ◽

Source Attribution ◽

Transmission Networks ◽

Sub Saharan ◽

Hiv 1

To reduce global HIV-1 incidence, there is a need to understand and disentangle HIV-1 transmission dynamics and to determine the geographic areas and populations that act as hubs or drivers of HIV-1 spread. In Sub-Saharan Africa (sSA), the region with the highest HIV-1 burden, information about such transmission dynamics is sparse. Phylogenetic inference is a powerful method for the study of HIV-1 transmission networks and source attribution. In this review, we assessed available phylogenetic data on mixing between HIV-1 hotspots (geographic areas and populations with high HIV-1 incidence and prevalence) and areas or populations with lower HIV-1 burden in sSA. We searched PubMed and identified and reviewed 64 studies on HIV-1 transmission dynamics within and between risk groups and geographic locations in sSA (published 1995–2021). We describe HIV-1 transmission from both a geographic and a risk group perspective in sSA. Finally, we discuss the challenges facing phylogenetic inference in mixed epidemics in sSA and offer our perspectives and potential solutions to the identified challenges.

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Cost effectiveness of single-dose nevirapine regimen for mothers and babies to decrease vertical HIV-1 transmission in sub-Saharan Africa

The Lancet ◽

10.1016/s0140-6736(99)07420-6 ◽

1999 ◽

Vol 354 (9185) ◽

pp. 803-809 ◽

Cited By ~ 43

Author(s):

E Marseille

Keyword(s):

Single Dose ◽

Cost Effectiveness ◽

Sub Saharan Africa ◽

Single Dose Nevirapine ◽

Sub Saharan ◽

Hiv 1

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Active Components from Cassia abbreviata Prevent HIV-1 Entry by Distinct Mechanisms of Action

International Journal of Molecular Sciences ◽

10.3390/ijms22095052 ◽

2021 ◽

Vol 22 (9) ◽

pp. 5052

Author(s):

Yue Zheng ◽

Xian-Wen Yang ◽

Dominique Schols ◽

Mattia Mori ◽

Bruno Botta ◽

...

Keyword(s):

Crude Extract ◽

Female Genital Tract ◽

Binding Activity ◽

Sub Saharan Africa ◽

Active Components ◽

Chemical Structures ◽

3D Space ◽

In Silico Study ◽

Sub Saharan ◽

Hiv 1

Cassia abbreviata is widely used in Sub-Saharan Africa for treating many diseases, including HIV-1 infection. We have recently described the chemical structures of 28 compounds isolated from an alcoholic crude extract of barks and roots ofC. abbreviata, and showed that six bioactive compounds inhibit HIV-1 infection. In the present study, we demonstrate that the six compounds block HIV-1 entry into cells: oleanolic acid, palmitic acid, taxifolin, piceatannol, guibourtinidol-(4α®8)-epiafzelechin, and a novel compound named as cassiabrevone. We report, for the first time, that guibourtinidol-(4α®8)-epiafzelechin and cassiabrevone inhibit HIV-1 entry (IC50 of 42.47 µM and 30.96 µM, respectively), as well as that piceatannol interacts with cellular membranes. Piceatannol inhibits HIV-1 infection in a dual-chamber assay mimicking the female genital tract, as well as HSV infection, emphasizing its potential as a microbicide. Structure-activity relationships (SAR) showed that pharmacophoric groups of piceatannol are strictly required to inhibit HIV-1 entry. By a ligand-based in silico study, we speculated that piceatannol and norartocarpetin may have a very similar mechanism of action and efficacy because of the highly comparable pharmacophoric and 3D space, while guibourtinidol-(4α®8)-epiafzelechin and cassiabrevone may display a different mechanism. We finally show that cassiabrevone plays a major role of the crude extract of CA by blocking the binding activity of HIV-1 gp120 and CD4.

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A Randomized Switch From Nevirapine-Based Antiretroviral Therapy to Single Tablet Rilpivirine/Emtricitabine/Tenofovir Disoproxil Fumarate in Virologically Suppressed Human Immunodeficiency Virus-1-Infected Rwandans

Open Forum Infectious Diseases ◽

10.1093/ofid/ofw141 ◽

2016 ◽

Vol 3 (3) ◽

Cited By ~ 2

Author(s):

Sean E. Collins ◽

Philip M. Grant ◽

Francois Uwinkindi ◽

Annie Talbot ◽

Eric Seruyange ◽

...

Keyword(s):

Human Immunodeficiency Virus ◽

Antiretroviral Therapy ◽

Tenofovir Disoproxil Fumarate ◽

Sub Saharan Africa ◽

Current Therapy ◽

Virologic Suppression ◽

Open Label ◽

Immunodeficiency Virus ◽

Sub Saharan ◽

Hiv 1

Abstract Background. Many human immunodeficiency virus (HIV)-infected patients remain on nevirapine-based antiretroviral therapy (ART) despite safety and efficacy concerns. Switching to a rilpivirine-based regimen is an alternative, but there is little experience with rilpivirine in sub-Saharan Africa where induction of rilpivirine metabolism by nevirapine, HIV subtype, and dietary differences could potentially impact efficacy. Methods. We conducted an open-label noninferiority study of virologically suppressed (HIV-1 ribonucleic acid [RNA] < 50 copies/mL) HIV-1-infected Rwandan adults taking nevirapine plus 2 nucleos(t)ide reverse-transcriptase inhibitors. One hundred fifty participants were randomized 2:1 to switch to coformulated rilpivirine-emtricitabine-tenofovir disoproxil fumarate (referenced as the Switch Arm) or continue current therapy. The primary efficacy endpoint was HIV-1 RNA < 200 copies/mL at week 24 assessed by the US Food and Drug Administration Snapshot algorithm with a noninferiority margin of 12%. Results. Between April and September 2014, 184 patients were screened, and 150 patients were enrolled; 99 patients switched to rilpivirine-emtricitabine-tenofovir, and 51 patients continued their nevirapine-based ART. The mean age was 42 years and 43% of participants were women. At week 24, virologic suppression (HIV-1 RNA level <200 copies/mL) was maintained in 93% and 92% in the Switch Arm versus the continuation arm, respectively. The Switch Arm was noninferior to continued nevirapine-based ART (efficacy difference 0.8%; 95% confidence interval, −7.5% to +12.0%). Both regimens were generally safe and well tolerated, although 2 deaths, neither attributed to study medications, occurred in participants in the Switch Arm. Conclusions. A switch from nevirapine-based ART to rilpivirine-emtricitabine-tenofovir disoproxil fumarate had similar virologic efficacy to continued nevirapine-based ART after 24 weeks with few adverse events.

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HIV-1 Full-Genome Phylogenetics of Generalized Epidemics in Sub-Saharan Africa: Impact of Missing Nucleotide Characters in Next-Generation Sequences

AIDS Research and Human Retroviruses ◽

10.1089/aid.2017.0061 ◽

2017 ◽

Vol 33 (11) ◽

pp. 1083-1098 ◽

Cited By ~ 9

Author(s):

Oliver Ratmann ◽

Chris Wymant ◽

Caroline Colijn ◽

Siva Danaviah ◽

Max Essex ◽

...

Keyword(s):

Sub Saharan Africa ◽

Full Genome ◽

Next Generation ◽

Sub Saharan ◽

Hiv 1

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Phylogenetic and Demographic Characterization of Directed HIV-1 Transmission Using Deep Sequences from High-Risk and General Population Cohorts/Groups in Uganda

Viruses ◽

10.3390/v12030331 ◽

2020 ◽

Vol 12 (3) ◽

pp. 331 ◽

Cited By ~ 4

Author(s):

Nicholas Bbosa ◽

Deogratius Ssemwanga ◽

Alfred Ssekagiri ◽

Xiaoyue Xi ◽

Yunia Mayanja ◽

...

Keyword(s):

High Risk ◽

General Population ◽

Lake Victoria ◽

Phylogenetic Analyses ◽

Sub Saharan Africa ◽

Transmission Dynamics ◽

Disease Spread ◽

Male Participant ◽

Population Sampling ◽

Hiv 1

Across sub-Saharan Africa, key populations with elevated HIV-1 incidence and/or prevalence have been identified, but their contribution to disease spread remains unclear. We performed viral deep-sequence phylogenetic analyses to quantify transmission dynamics between the general population (GP), fisherfolk communities (FF), and women at high risk of infection and their clients (WHR) in central and southwestern Uganda. Between August 2014 and August 2017, 6185 HIV-1 positive individuals were enrolled in 3 GP and 10 FF communities, 3 WHR enrollment sites. A total of 2531 antiretroviral therapy (ART) naïve participants with plasma viral load >1000 copies/mL were deep-sequenced. One hundred and twenty-three transmission networks were reconstructed, including 105 phylogenetically highly supported source–recipient pairs. Only one pair involved a WHR and male participant, suggesting that improved population sampling is needed to assess empirically the role of WHR to the transmission dynamics. More transmissions were observed from the GP communities to FF communities than vice versa, with an estimated flow ratio of 1.56 (95% CrI 0.68–3.72), indicating that fishing communities on Lake Victoria are not a net source of transmission flow to neighboring communities further inland. Men contributed disproportionally to HIV-1 transmission flow regardless of age, suggesting that prevention efforts need to better aid men to engage with and stay in care.

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