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Featured researches published by Gabriele Riedner.


AIDS | 2010

Epidemiology of HIV infection in the Middle East and North Africa.

Laith J. Abu-Raddad; Nahla Hilmi; Ghina Mumtaz; Manal Benkirane; Francisca Ayodeji Akala; Gabriele Riedner; Oussama Tawil; David Wilson

Objective:The Middle East and North Africa (MENA) region continues to be perceived as a region with very limited HIV epidemiological data, raising many controversies about the status of the epidemic in this part of the world. The objective of this review and synthesis was to address the dearth of strategic interpretable data on HIV in MENA by delineating a data-driven overview of HIV epidemiology in this region. Methods:A comprehensive systematic review of HIV, sexually transmitted infections (STIs) and risk behavior studies in MENA, irrespective of design, was undertaken. Sources of data included Medline for peer-reviewed publications, Google Scholar for other scientific literature published in nonindexed local and regional journals, international organizations reports and databases, country-level reports and database including governmental and nongovernmental organizations publications, as well as various other institutional documents. Results:Over 5000 sources of data related to HIV and STIs were identified and reviewed. The quality of data and nature of study designs varied substantially. There was no evidence for a sustainable HIV epidemic in the general population in any of the MENA countries, except possibly for southern Sudan. The general pattern in different countries in MENA points towards emerging epidemics in high-risk populations including injecting drug users, men who have sex with men (MSM) and to a lesser extent female sex workers, with heterogeneity between countries on the relative role of each of these high-risk groups. Exogenous HIV exposures among nationals linked to travel abroad appeared to be the dominant HIV transmission pattern in a few MENA countries with no evidence for much epidemic or endemic transmission. The role of bridging populations in bridging the HIV infection to the general population was found to be very limited. Conclusion:Although they do not provide complete protection against HIV spread, near universal male circumcision and possibly the prevailing sexually conservative cultural norms seemed to have played so far a protective role in slowing and limiting HIV transmission in MENA relative to other regions. If the existing social and epidemiological context remains largely the same, HIV epidemic transmission is likely to remain confined to high-risk populations and their sexual partners, in addition to exogenous exposures. HIV prevention efforts in this region, which continue to be stymied by stigma associated with HIV/AIDS and related risk behaviors, need to be aggressively expanded with a focus on controlling HIV spread along the contours of risk and vulnerability. There is still a window of opportunity to control further HIV transmission among high-risk groups in MENA that, if missed, may entail a health and socioeconomic burden that the region, in large part, is unprepared for.


PLOS Medicine | 2011

Are HIV Epidemics among Men Who Have Sex with Men Emerging in the Middle East and North Africa?: A Systematic Review and Data Synthesis

Ghina Mumtaz; Nahla Hilmi; Willi McFarland; Rachel L. Kaplan; Francisca Ayodeji Akala; Iris Semini; Gabriele Riedner; Oussama Tawil; David Wilson; Laith J. Abu-Raddad

A systematic review by Laith Abu-Raddad and colleagues collates and analyzes the epidemiology of HIV among men who have sex with men in Middle Eastern and North African countries.


AIDS | 2006

Decline in sexually transmitted infection prevalence and HIV incidence in female barworkers attending prevention and care services in Mbeya Region, Tanzania

Gabriele Riedner; Oliver Hoffmann; Mary Rusizoka; Donan Mmbando; Leonard Maboko; Heiner Grosskurth; Jim Todd; Richard Hayes; Michael Hoelscher

Objective:To assess trends in sexually transmitted infection (STI) prevalence and HIV incidence and associated factors in a cohort of female barworkers exposed to behavioural interventions and STI screening and treatment. Methods:An open cohort of 600 female barworkers in Mbeya Region, Tanzania was offered 3-monthly information and education sessions on HIV/STI and reproductive health, voluntary HIV counselling and testing and clinical health check-ups including STI syndromic management with simple STI laboratory support. Outcome assessments included HIV, herpes simplex virus type 2 (HSV-2) and syphilis serology, polymerase chain reaction for Neisseria gonorrhoeae, Chlamydia trachomatis and ulcerative STI, microscopy for Trichomonas vaginalis, Candida albicans and bacterial vaginosis and interviews on sociodemographic and behavioural characteristics. Results:Over a period of 30 months 600 barworkers were enrolled at the baseline examination round and 153 thereafter as replacements for losses to follow-up. At 3-monthly examinations the prevalence of gonorrhoea declined steadily from 22.2 to 6.8% (odds ratio for trend per quarter: 0.81; P < 0.001). The prevalence of all other STI/RTI, except for genital herpes and bacterial vaginosis, also decreased significantly. HIV incidence declined from 13.9/100 to 5.0/100 person-years over three consecutive 9-month periods. HIV incidence was significantly associated with genital ulcers and positive syphilis serology, but not with genital herpes or HSV-2 seropositivity. Conclusion:A relatively simple intervention consisting of regular 3-monthly STI screening and syndromic management in combination with HIV/STI information and counselling sessions was well accepted and effective in reducing STI among barworkers. Such interventions should be implemented more widely in high-risk environments in sub-Saharan Africa.


AIDS Research and Human Retroviruses | 2010

Scarcity or Absence of Humoral Immune Responses in the Plasma and Cervicovaginal Lavage Fluids of Heavily HIV-1-Exposed But Persistently Seronegative Women

Jiri Mestecky; Peter F. Wright; Lucia Lopalco; Herman F. Staats; Pamela A. Kozlowski; Zina Moldoveanu; Rashada C. Alexander; Rose Kulhavy; Claudia Pastori; Leonard Maboko; Gabriele Riedner; Yuwei Zhu; Terri Wrinn; Michael Hoelscher

To address an existing controversy concerning the presence of HIV-1-specific antibodies of the IgA isotype in the female genital tract secretions of highly-exposed but persistently seronegative (HEPSN) women, 41 samples of plasma and cervicovaginal lavage (CVL) fluid were distributed to six laboratories for their blinded evaluation using ELISA with 10 different HIV-1 antigens, chemiluminescence-enhanced Western blots (ECL-WB), and virus neutralization. HIV-specific IgG or IgA antibodies in plasma samples from HEPSN women were absent or detectable only at low levels. In CVL, 11/41 samples displayed low levels of reactivity in ELISA against certain antigens. However, only one sample was positive in two of five laboratories. All but one CVL sample yielded negative results when analyzed by ECL-WB. Viral neutralizing activity was either absent or inconsistently detected in plasma and CVL. Plasma and CVL samples from 26 HIV-1-infected women were used as positive controls. Irrespective of the assays and antigens used, the results generated in all laboratories displayed remarkable concordance in the detection of HIV-1-specific antibodies of the IgG isotype. In contrast, IgA antibodies to HIV-1 antigens were not detected with consistency, and where present, IgA antibodies were at markedly lower levels than IgG. Although HIV-neutralizing activity was detected in plasma of all HIV-1-infected women, only a few of their CVL samples displayed such activity. In conclusion, frequent HIV-1 sexual exposure does not stimulate uniformly detectable mucosal or systemic HIV-1-specific responses, as convincingly documented in the present blindly performed study using a broad variety of immunological assays. Although HIV-1-infection leads to vigorous IgG responses in plasma and CVL, it does not stimulate sustained IgA responses in either fluid.


AIDS | 2010

HIV prevalence and characteristics of sex work among female sex workers in Hargeisa, Somaliland, Somalia.

Kelsi Kriitmaa; Adrienne Testa; Mohamed Osman; Ivana Bozicevic; Gabriele Riedner; Jacqueline Malungu; Greg Irving; Ismail Abdalla

Objective:To measure prevalence of HIV and syphilis and describe characteristics of sex work among female sex workers (FSWs) in Hargeisa, Somaliland, Somalia. Methods:A cross-sectional survey recruited 237 FSWs using respondent-driven sampling (RDS). A face-to-face, structured interview using handheld-assisted personal interviewing (HAPI) on personal digital assistants (PDAs) was completed and blood collected for serological testing. Results:FSWs 15–19 years old accounted for 6.9% of the population; 20–24 year-old constituted an additional 18.0%. The majority (86.6%) never attended school. International (59.0%) and interzonal (10.7%) migration was common. Most (95.7%) reported no other source of income; 13.8% had five or more clients in the last 7 days. A minority (38.4%) had heard of STIs, even fewer (6.9%) held no misconceptions about HIV. Only 24% of FSW reported using a condom at last transactional sex, and 4% reported ever been tested for HIV. HIV prevalence was 5.2% and syphilis prevalence was 3.1%. Conclusion:Sex work in Hargeisa, Somaliland, Somalia, is characterized by high numbers of sexual acts and extremely low knowledge of HIV. This study illustrates the need for targeted HIV prevention interventions focusing on HIV testing, risk-reduction awareness raising, and review of condom availability and distribution mechanisms among FSWs and males engaging with FSWs.


Epidemics | 2010

HSV-2 serology can be predictive of HIV epidemic potential and hidden sexual risk behavior in the Middle East and North Africa

Laith J. Abu-Raddad; Joshua T. Schiffer; Rhoda Ashley; Ghina Mumtaz; Ramzi A. Alsallaq; Francisca Ayodeji Akala; Iris Semini; Gabriele Riedner; David Wilson

BACKGROUND HIV prevalence is low in the Middle East and North Africa (MENA) region, though the risk or potential for further spread in the future is not well understood. Behavioral surveys are limited in this region and when available have serious limitations in assessing the risk of HIV acquisition. We demonstrate the potential use of herpes simplex virus-2 (HSV-2) seroprevalence as a marker for HIV risk within MENA. METHODS We designed a mathematical model to assess whether HSV-2 prevalence can be predictive of future HIV spread. We also conducted a systematic literature review of HSV-2 seroprevalence studies within MENA. RESULTS We found that HSV-2 prevalence data are rather limited in this region. Prevalence is typically low among the general population but high in established core groups prone to sexually transmitted infections such as men who have sex with men and female sex workers. Our model predicts that if HSV-2 prevalence is low and stable, then the risk of future HIV epidemics is low. However, expanding or high HSV-2 prevalence (greater than about 20%), implies a risk for a considerable HIV epidemic. Based on available HSV-2 prevalence data, it is not likely that the general population in MENA is experiencing or will experience such a considerable HIV epidemic. Nevertheless, the risk for concentrated HIV epidemics among several high-risk core groups is present. CONCLUSIONS HSV-2 prevalence surveys provide a useful mechanism for identifying and corroborating populations at risk for HIV within MENA. HSV-2 serology offers an effective tool for probing hidden sexual risk behaviors in a region where quality behavioral data are limited.


Current Opinion in Hiv and Aids | 2014

The emerging face of the HIV epidemic in the Middle East and North Africa

Ghina Mumtaz; Gabriele Riedner; Laith J. Abu-Raddad

Purpose of reviewA volume of quality HIV data has materialized recently in the Middle East and North Africa (MENA). This review provides a thematic narrative of the patterns of HIV infection transmission in this region in light of these data. Recent findingsTens of integrated bio-behavioral surveillance surveys among hard-to-reach key populations at higher risk have been conducted in MENA in the recent years. Many of the studies reported appreciable and growing HIV prevalence. A few studies found alarming prevalence of as much as 87.2% HIV prevalence among people who inject drugs in Tripoli, Libya. The discovery of these hitherto hidden epidemics was unsettling to some authorities after years in which the importance of a focus on HIV prevention among key populations was not recognized. SummaryThe new data from MENA indicate growing HIV epidemics among key populations across the region. There is heterogeneity, however, as to which key populations are affected and in what proportions in different countries. In a few countries, HIV appears to affect only one key population and often there is substantial geographical heterogeneity in HIV transmission. Data are indicative of a growing HIV disease burden in this part of the globe, in contrast with the declining epidemics in most other regions.


Sexually Transmitted Infections | 2013

HIV surveillance in MENA: recent developments and results

Ivana Bozicevic; Gabriele Riedner; Jesus Maria Garcia Calleja

Objectives To provide an overview of the current level of development and results from the national HIV surveillance systems of the 23 countries of the Middle East and North Africa (MENA), and to assess the quality of HIV surveillance systems in the period 2007–2011. Methods A questionnaire was used to collect the information about the structure, activities and the results of HIV surveillance systems from the National AIDS Programmes. Assessment of the quality was based on four indicators: timeliness of data collection, appropriateness of populations under surveillance, consistency of the surveillance sites and groups measured over time, and coverage of the surveillance system. Results Only in four countries did surveillance systems enable assessment of epidemic trends in the same populations and locations over time, such as in pregnant women (Morocco, Iran), injecting drug users (Iran, Pakistan), female sex workers (Djibouti, Morocco) and male sex workers (Pakistan). There is increasing evidence of HIV infection being firmly established in at least one of the populations most at risk of HIV in nine MENA countries, while lower risk populations show elevated HIV prevalence in South Sudan, Djibouti and some parts of Somalia. Conclusions The performance of HIV surveillance systems in several of the MENA countries has improved in recent years. The extent of HIV epidemics in the populations most at risk of HIV is still largely unknown in 10 countries. Multiple data sources that most of the countries still lack would enable indirectly estimation not only of the patterns of HIV epidemics but also the effectiveness of HIV responses.


AIDS | 2010

A review of HIV testing and counseling policies and practices in the Eastern Mediterranean Region.

Joumana Hermez; Jenny Petrak; Mehdi Karkouri; Gabriele Riedner

Objective:To review HIV testing and counseling policies and practices in the World Health Organizations (WHO) Eastern Mediterranean Region. Methods:We reviewed gray and published literature on HIV testing policies and practices in the 22 countries of the Eastern Mediterranean Region, including surveillance, monitoring and evaluation reports. Missing or unclear information was clarified by telephone interviews of key informants. Field observations were conducted in four countries. Results:Of reported diagnostic HIV tests conducted in the Eastern Mediterranean Region from 1995 to 2008, 59.3% were carried out on migrant workers. Only 4.0% were carried out on key populations at higher risk for HIV and 8.1% were conducted in sexually transmitted infection, tuberculosis and antenatal care services. The largest proportions of HIV-positive cases identified were among key populations at higher risk (23.4%) and in sexually transmitted infection, tuberculosis and antenatal care services (17.5%). Mandatory testing was the most common approach to identifying HIV-positive cases, yet most policy documents reviewed identified voluntary counseling and testing as a key intervention for prevention, care and treatment. Provider initiated testing and counseling was rarely considered. HIV testing strategies are cumbersome, as they require central laboratory-based Enzyme Linked Immuno-Sorbant Assay (ELISA) and/or Western Blot confirmation in most countries presenting barriers to receiving results. Conclusion:Although policies in the Eastern Mediterranean Region include a mix of mandatory and voluntary HIV testing, mandatory testing predominates, especially for migrant and foreign workers and key populations at higher risk of HIV. There is a paucity of programs providing voluntary testing. Strategies to enhance access to true voluntary HIV testing and counseling services are urgently needed, particularly targeting key populations at higher risk.


PLOS ONE | 2013

Effect of Genital Herpes on Cervicovaginal HIV Shedding in Women Co-Infected with HIV AND HSV-2 in Tanzania.

Jim Todd; Gabriele Riedner; Leonard Maboko; Michael Hoelscher; Helen A. Weiss; Eligius Lyamuya; David Mabey; Mary Rusizoka; Laurent Bélec; Raymond Hayes

Objectives To compare the presence and quantity of cervicovaginal HIV among HIV seropositive women with clinical herpes, subclinical HSV-2 infection and without HSV-2 infection respectively; to evaluate the association between cervicovaginal HIV and HSV shedding; and identify factors associated with quantity of cervicovaginal HIV. Design Four groups of HIV seropositive adult female barworkers were identified and examined at three-monthly intervals between October 2000 and March 2003 in Mbeya, Tanzania: (1) 57 women at 70 clinic visits with clinical genital herpes; (2) 39 of the same women at 46 clinic visits when asymptomatic; (3) 55 HSV-2 seropositive women at 60 clinic visits who were never observed with herpetic lesions; (4) 18 HSV-2 seronegative women at 45 clinic visits. Associations of genital HIV shedding with HIV plasma viral load (PVL), herpetic lesions, HSV shedding and other factors were examined. Results Prevalence of detectable genital HIV RNA varied from 73% in HSV-2 seronegative women to 94% in women with herpetic lesions (geometric means 1634 vs 3339 copies/ml, p = 0.03). In paired specimens from HSV-2 positive women, genital HIV viral shedding was similar during symptomatic and asymptomatic visits. On multivariate regression, genital HIV RNA (log10 copies/mL) was closely associated with HIV PVL (β = 0.51 per log10 copies/ml increase, 95%CI:0.41–0.60, p<0.001) and HSV shedding (β = 0.24 per log10 copies/ml increase, 95% CI:0.16–0.32, p<0.001) but not the presence of herpetic lesions (β = −0.10, 95%CI:−0.28–0.08, p = 0.27). Conclusions HIV PVL and HSV shedding were more important determinants of genital HIV than the presence of herpetic lesions. These data support a role of HSV-2 infection in enhancing HIV transmissibility.

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Iris Semini

Joint United Nations Programme on HIV/AIDS

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Jim Todd

University of London

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