SARS-CoV-2 Antibody Seroprevalence in Gabon: Findings from a Nationwide Household Serosurvey in a Sub-Saharan Africa Country.

Seroconversion surveys of anti-SARS-CoV-2 antibodies provide accurate estimates of the prevalence of SARS-CoV-2 infections. This nationwide population-based cross-sectional serosurvey aimed to evaluate the prevalence of SARS-CoV-2 antibodies among residents in Gabon and compare the estimated cumulative number of COVID-19 cases with the officially registered number of laboratory-confirmed cases up to December 2021. Households in each province were randomly selected. Twenty-eight localities, including sixteen urban and twelve rural, were randomly selected for the study. Whole blood samples were collected in dry tubes from all study participants nationwide within 15 days. Serum samples were used to measure SARS-CoV-2-specific ELISA titers. Overall, data from 1672 households were analyzed. Out of the 3659 participants, 3175 were found to be positive for SARS-CoV-2 antibodies, resulting in a crude seroprevalence of 86.77%. Stratification of study participants by age group showed the highest seroprevalences in the 20-29 and 40-49 age groups with 91.78% (95% CI: 89.5-93.6) and 91.42% (95% CI: 88.7-93.5), respectively. Nyanga province had the lowest prevalence (72.8%), and Estuaire and Ogooué-Lolo provinces had the highest prevalence (90 and 92%). Our results suggest a high transmission rate in the Gabonese population 21 months after the first SARS-CoV-2 case in the country. This high seroprevalence estimate could indicate that the population may not have adequately implemented or appropriately adhered to the applied infection control measures.

HIV protease resistance mutations in patients receiving second-line antiretroviral therapy in Libreville, Gabon.

INTRODUCTION: In 2022, the WHO reported that 29.8 million people around the world were living with HIV (PLHIV) and receiving antiretroviral treatment (ART), including 25| 375 people in Gabon (54% of all those living with HIV in the country). The literature reports a frequency of therapeutic failure with first-line antiretrovirals (ARVs) of between 20% and 82%. Unfortunately, data relating to the failure of second-line ARVs are scarce in Gabon. This study aims to determine the profiles of HIV drug resistance mutations related to protease inhibitors in Gabon. METHODOLOGY: Plasma from 84 PLHIV receiving ARVs was collected from 2019 to 2021, followed by RNA extraction, amplification, and sequencing of the protease gene. ARV resistance profiles were generated using the Stanford interpretation algorithm version 8.9-1 ( https://hivdb.stanford.edu ) and statistical analyses were performed using EpiInfo software version 7.2.1.0 (CDC, USA). RESULTS: Of 84 HIV plasma samples collected from 45 men and 39 women, 342 mutations were detected. Of these, 43.3% (148/342) were associated with nucleoside reverse transcriptase inhibitors (NRTIs), 30.4% (104/342) with non-nucleoside reverse transcriptase inhibitors (NNRTIs), and 26.3% (90/342) with protease inhibitors (PIs). Most NRTI mutations were associated with thymidine analogues (TAMs) (50.7%; 75/148), including T215F/V (14.9%; 22/148), D67DN/E/G/N/T (10.1%; 15/148), M41L (9.5%; 14/148), and K70E/KN/S/R (9.5%; 14/148). Resistance mutations related to non-TAM NRTIs (33.1%; 49/148) were M184V (29.1%; 43/148), and L74I/V (8.1%; 12/148). NNRTI mutations were predominantly K103N/S (32.7%; 34/104), V108I (10.6%; 11/104), A98G (10.6%; 11/104), and P225H (9.6%; 10/104). Minor mutations associated with PIs (60.0%; 54/90) were predominantly K20I (15.6%; 14/90) and L10F/I/V (14.5%; 13/90). The major mutations associated with PIs (40.0%; 36/90) were M41L (12.2%; 11/90), I84V (6.7%; 06/90), and V82A (6.7%; 06/90). The four most prescribed therapeutic regimens were TDF + 3TC + LPV/r (20.3%; 17/84), ABC + DDI + LPV/r (17.9%; 15/84), TDF + FTC + LPV/r (11.9%; 10/84), and ABC + 3TC + LPV/r (11.9%; 10/84). CONCLUSION: This study revealed that HIV drug resistance mutations are common in Gabon. The major mutations associated with PIs were M41L, I84V, and V82A. There is a need for access to new NRTIs, NNRTIs, and PIs for a better therapeutic management of PLHIV in Gabon.

Low prevalence of HCV infection with predominance of genotype 4 among HIV patients living in Libreville, Gabon.

BACKGROUND: Gabon is an endemic area for human immunodeficiency virus (HIV) and hepatitis C virus (HCV) and the risk of co-infection is high. METHOD: Between November 2015 and April 2016, we conducted retrospective study on HCV infection among people living with HIV/AIDS (PLHA). A total of 491 PLHA were included in this study and tested for the presence of HCV infection. HIV viral loads were obtained using the Generic HIV viral Load® assay and the CD4+ T cells count was performed using BD FACSCount™ CD4 reagents. HCV screening was performed using the MP Diagnostics HCV ELISA 4.0 kit. HCV genotypes were determined by sequence analysis of NS5B and Core regions. The Mann-Whitney test was used to compare the groups. Chi-2 test and Fisher's Exact Test were used to compare prevalence. RESULTS: HCV seroprevalence was 2.9% (14/491), (95% confidence interval (CI):1.4-4.3%). The percentage of HCV viremic patients, defined by the detection of HCV RNA in plasma, was 57% (8/14), representing 1.6% of the total population. HCV seroprevalence and replicative infection were not statistically differ with gender. The percentage of co-infection increased with age. No correlation with CD4+ T cells count and HIV viral load level was registered in this study. Identified HCV strains were predominantly of genotype 4 (87.5%) including 4k, 4e, 4g, 4p, 4f and 4c subtypes. Only one strain belonged to genotype 2 (subtype 2q). Analysis of the NS5B region did not reveal the presence of resistance-associated substitutions for sofosbuvir. CONCLUSION: A systematic screening of hepatitis C is therefore strongly recommended as well as genotyping of HCV strains in order to adapt treatments for the specific case of people living with HIV/AIDS in Central Africa.

Description of Gabonibacter massiliensis gen. nov., sp. nov., a New Member of the Family Porphyromonadaceae Isolated from the Human Gut Microbiota.

The identification of human-associated bacteria is very important to control infectious diseases. In recent years, we diversified culture conditions in a strategy named culturomics, and isolated more than 100 new bacterial species and/or genera. Using this strategy, strain GM7, a strictly anaerobic gram-negative bacterium was recently isolated from a stool specimen of a healthy Gabonese patient. It is a motile coccobacillus without catalase and oxidase activities. The genome of Gabonibacter massiliensis is 3,397,022 bp long with 2880 ORFs and a G+C content of 42.09 %. Of the predicted genes, 2,819 are protein-coding genes, and 61 are RNAs. Strain GM7 differs from the closest genera within the family Porphyromonadaceae both genotypically and in shape and motility. Thus, we propose that strain GM7T (=CSUR P2336 = DSM 101039) is the type strain of the new genus Gabonibacter gen. nov. and the new species G. massiliensis gen. nov., sp. nov.

Human papillomavirus genotypes distribution in cervical cancer cases in Gabon.

BACKGROUND: Cervical cancer is a real public health problem in African countries. The relation between HPV and cervical cancer is well established. However, it is known that the distribution of HPV genotypes differ geographically and this may influence the effectiveness of the three available vaccines, which among other HPV genotypes targets the genotypes 16 and 18 that cause about 70 % of cervical cancers cases. The objective of this study was to identify for the first time the HPV genotypes distribution in cervical cancer specimens obtained from Gabonese women. METHODS: A total of 105 cervical samples including 93 formalin-fixed paraffin embedded tissues collected between 2007 and 2013 and 12 fresh biopsies collected in August 2013 were investigated. The presence of HPV DNA was analyzed by nested PCR with primers MY09/11 and GP5+/6+ followed by sequencing for HPV genotyping. RESULTS: Amplification of the housekeeping gene (ß-globin) with PCO4/GH20 primers was successful for 91.4 % (96/105) of the cervical cancer samples and HPV DNA was detected in all the 96 samples. Five different HPV genotypes were identified. HPV 16 [58.3 %; 95 % IC: 48.44-68.16] was the most common genotype followed by HPV 33 [25.0 %; 95 % IC: 16.34-33.66], HPV 18 [8.4 %; 95 % IC: 2.86-13.94], HPV 70 [7.3 %; 95 % IC: 2.1-12.5] and HPV 31 [1.1 %; 95 % IC: -0.986-3.186]. HPV 16 was also the most prevalent in all histological malignant lesions. It was found in 56.6 % of squamous cervical carcinoma and 69.2 % of adenocarcinoma. Concerning the HPV positive adenocarcinoma cases, HPV 18 was identified in 7.7 % (1/13). CONCLUSION: These findings show the predominance of HPV 16 in cervical cancer cases among Gabonese women. However, HPV33 is more prevalent than HPV18. Our study suggests that HPV vaccines may be effective at reducing the burden of cervical cancer in Gabon.

Co-circulation of Plasmodium and Bacterial DNAs in Blood of Febrile and Afebrile Children from Urban and Rural Areas in Gabon.

Malaria is considered to be the most common etiology of fever in sub-Saharan Africa while bacteremias exist but are under assessed. This study aimed to assess bacteremias and malaria in children from urban and rural areas in Gabon. DNA extracts from blood samples of 410 febrile and 60 afebrile children were analyzed using quantitative polymerase chain reaction. Plasmodium spp. was the microorganism most frequently detected in febrile (78.8%, 323/410) and afebrile (13.3%, 8/60) children, (P < 0.001). DNA from one or several bacteria were detected in 15 febrile patients (3.7%) but not in the controls (P = 0.1). This DNA was more frequently detected as co-infections among febrile children tested positive for Plasmodium (4.6%, 15/323) than in those tested negative for Plasmodium (0%, 0/87; P = 0.04). The bacteria detected were Streptococcus pneumoniae 2.4% (10/410), Staphylococcus aureus 1.7% (7/410), Salmonella spp. 0.7% (3/410), Streptococcus pyogenes 0.2% (1/410) and Tropheryma whipplei 0.2% (1/410) only in febrile children. Coxiella burnetii, Borrelia spp., Bartonella spp., Leptospira spp., and Mycobacterium tuberculosis were not observed. This paper reports the first detection of bacteremia related to T. whipplei in Gabon and shows that malaria decreases in urban areas but not in rural areas. Co-infections in febrile patients are common, highlighting the need to improve fever management strategies in Gabon.

Human papillomavirus genotypes distribution among Gabonese women with normal cytology and cervical abnormalities.

BACKGROUND: Cervical cancer is one of the most common tumors affecting women with a disproportionate mortality occurring in developing countries. Despite the high prevalence of cervical cancer and cervical neoplasia in Gabon, few studies have been performed to evaluate the prevalence and determinants of HPV infection in this country. The aim of this study was to determine the HPV prevalence and distribution in a population of Gabonese women with normal cytology and cervical abnormalities. METHODS: A total of 200 cervical samples collected in the "Departement d'Anatomie et de Cytologie Pathologiques" of the "Faculté de Medecine et des Sciences de la Santé" in Libreville, Gabonwere analyzed. Cytological status was classified according to Bethesda 2001. Nested polymerase chain reaction (PCR) using consensus degenerate PCR primers (MY09/11 and GP5+/6+) was performed for the detection of HPV DNA and HPV typing was done by DNA sequencing. RESULTS: Cytological analysis showed that 87 % of women had normal cytology (n = 174/200). Among the 26 women with cytological abnormalities, predominance (61.5 %; 16/26) of low grade squamous intraepithelial lesion (LSIL) was found and no cervical cancer case was detected. Overall, HPV DNA was detected in 60 % of women (120/200). With respect to the cytological status, HPV DNA was found in 57.5 % of women with normal cervix and 76.9 % of women with abnormal cytology. HPV genotyping was performed on 114 HPV positive cases and revealed the presence of 11 distinct genotypes: 16, 18, 33, 31, 56, 6, 66, 70, 35, 45 and 81. The high risk type HPV 16 was the most common genotype found in all cytological categories. Six HPV positive samples could not be typed by DNA sequencing, probably due to multiple HPV infection. Evaluation of possible risk factors showed that HPV infection was related positively with number of sexual partners (≥3, OR = 2.3; 95 % CI, 1.3-4.3), history of sexually transmitted infection (Chlamydia, OR = 1.9; 95 % CI, 1.01-3.4) and marital status (single, OR = 2.0; 95 % CI, 1.1-3.5). CONCLUSION: The prevalence of HPV infection among Gabonese women is high. Our findings highlight the need to set up a national program to fight cervical cancer, combining Pap smear test and HPV testing, to improve cervical cancer prevention in Gabon.

Mansonella, including a Potential New Species, as Common Parasites in Children in Gabon.

BACKGROUND: Like other tropical African countries, Gabon is afflicted by many parasitic diseases, including filariases such as loiasis and mansonellosis. This study aimed to assess the prevalence of these two filarial diseases in febrile and afebrile children using quantitative real-time PCR and standard PCR assays coupled with sequencing. METHODOLOGY/PRINCIPAL FINDINGS: DNA from blood specimens of 1,418 Gabonese children (1,258 febrile and 160 afebrile) were analyzed. Overall, filarial DNA was detected in 95 (6.7%) children, including 67 positive for M. perstans (4.7%), which was the most common. M. perstans was detected in 61/1,258 febrile children (4.8%) and 6/160 afebrile children (3.8%, P = 0.6). Its prevalence increased statistically with age: 3.5%, 7.7% and 10.6% in children aged ≤ 5, 6-10 and 11-15 years, respectively. M. perstans prevalence was significantly higher in Koulamoutou and Lastourville (12% and 10.5%, respectively) than in Franceville and Fougamou (2.6% and 2.4%, respectively). Loa loa was detected in seven febrile children including one co-infection with M. perstans. Finally, 21 filarial DNA positive were negative for M. perstans and Loa loa, but ITS sequencing could be performed for 12 and allowed the identification of a potential new species of Mansonella provisionally called "DEUX". Mansonella sp. "DEUX" was detected only in febrile children. CONCLUSIONS/SIGNIFICANCE: Further study should be performed to characterize Mansonella sp. "DEUX" and evaluate the clinical significance of mansonellosis in humans.

LETTER TO THE EDITOR Performance of the ViroSeq® HIV-1 Genotyping System v2.0 in Central Africa.

Resistance genotypes in pol gene of HIV-1 were obtained by the ViroSeq(®) HIV-1 Genotyping System v2.0 (Celera Diagnostics, Alameda, CA, USA) in 138 of 145 (95%) antiretroviral treatment-experienced adults in virological failure living in Central Africa (Cameroon, Central African Republic, Chad, Gabon). HIV-1 group M exhibited broad genetic diversity. Performance of the 7 ViroSeq(®) sequencing primers showed high failure rate, from 3% to 76% (D: 76%; F: 17%; A and H: 15%; G and B: 4%; C: 3%). These findings emphasize the need of updating the ViroSeq(®) HIV-1 genotyping system for non-B subtypes HIV-1.

The preliminary study of p53 codon 72 polymorphism and risk of cervical carcinoma in Gabonese women.

Cervical cancer is the leading cause of cancer-related death in Africa and the first most common cancer in Gabonese women due to infection of high-risk human papillomavirus (HPV). However, other cofactors such as genetic factors also come into play. A common polymorphism of the p53 codon 72 in exon 4 with two alleles encoding arginine or proline is known at this locus. The homozygous arginine form of this polymorphism has been associated with the development of cervical cancer as an increased genetic risk factor. However, the results are still controversial. This study aims to investigate whether the genotype distribution of p53 codon 72 may be a risk factor for cervical cancer among Gabonese women. Samples from 102 Gabonese women, 31 diagnosed with cervical cancer and 71 healthy controls, were used. HPV detection was done by nested PCR with MY09/11 and GP5+/6+ primers followed by sequencing for HPV genotyping. p53 codon 72 polymorphism determination was performed by allele-specific PCR assay. Viral DNA was detected in 87.1 % of cases and in 54.93 % of control. HPV 16 was the most predominant in cancer and controls cases. The distribution of Arg/Arg, Arg/Pro and Pro/Pro genotypes was 35.5, 51.6 and 12.9 % in the cervical cancer group and 22.5, 62 and 15.5 % in the control group. No significant association was found between polymorphism of p53 itself as well as in combination with HPV16/18 infection and risk of development of cervical cancer among Gabonese women. Thus, the polymorphism of p53 codon 72 in exon 4 does not seem to play a role in the development of cervical cancer among Gabonese women.

Association of inconclusive sera for human immunodeficiency virus infection with malaria and Epstein-Barr virus infection in Central Africa.

Among 464 sera from adults in Cameroon, 56 (12.1%) gave inconclusive HIV serology. All were negative for HIV-1 DNA; 44.6% (n = 25) were significantly associated with Plasmodium (42.8%) or Epstein-Barr virus (EBV) (17.8%) infections. In Central Africa, sera giving inconclusive results for HIV are frequently associated with malaria, EBV infection, or both.

Field evaluation in Chad of community usage of CD4 T lymphocyte counting by alternative single-platform flow cytometry.

BACKGROUND: Field and community evaluation of the routine usage of CD4 T counting platforms is essential in resource-poor countries for efficient and cost-effective monitoring of HIV-infected adults and children attending health care centers. METHODS: We herein addressed the principal issues raised by the implementation of the single-platform, volumetric Auto40 flow cytometer (Apogee Flow Systems Ltd, Hemel Hempstead, UK) in 8 community HIV monitoring laboratories of different levels throughout Chad. This is a country with particularly difficult conditions, both in terms of climate and vast geographical territory, making the decentralization of the therapeutic management of HIV-infected patients challenging. RESULTS: The routine usage of the Auto40 flow cytometers for a period of 5 years (2008-2013) confirms the reliability and robustness of the analyzer for community-based CD4 T cell enumeration in terms of both absolute numbers and percentages to enable accurate monitoring of HIV-infected adults and children. However, our observations suggest that the Auto40 mini flow cytometer is not suitable for all laboratories as it is oversized and ultimately very expensive. CONCLUSION: The Chad experience with the Auto40 flow cytometer suggests that its usage in resource-limited settings should be mainly reserved to reference (level 1) or district (level 2) laboratories, rather than to laboratories of health care centres (level 3).

Single-platform, volumetric, CD45-assisted pan-leucogating flow cytometry for CD4 T lymphocytes monitoring of HIV infection according to the WHO recommendations for resource-constrained settings.

BACKGROUND: Validation of new affordable CD4 T cell measurement technologies is crucial specifically in resource-poor countries for antiretroviral treatment eligibility and immunologic CD4 monitoring of HIV-infected patients. METHODS: The absolute and percentage CD4 T cell counts of 258 HIV-1-infected blood samples (182 adults and 76 children), living in N'Djamena, Chad, were performed by single-platform, volumetric, CD45-assisted pan-leucogating Auto40 flow cytometer (Apogee Flow Systems Ltd, Hemel Hempstead, UK) comparing to the FACSCalibur flow cytometer as a reference method. RESULTS: Absolute and percentage CD4 T cell counts obtained by Auto40 and FACSCalibur of 258 HIV-1-infected blood samples were highly correlated (r = 0.99 and r = 0.96, respectively). The mean absolute bias and percent bias between Apogee Auto40 and FACSCalibur absolute CD4 T cell counts, were -9.4 cells/µl with limits of agreement from -15 to 93 cells/µl, and +2.0% with limits of agreement from -0.9 to 4.9%, respectively. The mean of absolute bias and percent bias between Apogee Auto40 and FACSCalibur of CD4 percentage results were +0.4% (95% CI: -0.02 - 0.86) with limits of agreement from -2.4 to 0.3%, and +3.0% with limits of agreement from -6.6 to 0.6%, respectively. The Auto40 counting allowed to identify the majority of adults with CD4 T cells below 200 cells/µl (sensitivity: 89%; specificity: 99%) or below 350 cells/µl (sensitivity: 94%; specificity:98%); and of children below 750 cells/µl (sensitivity: 99%; specificity: 96%) or below 25% CD4+ (sensitivity: 94%; specificity: 98%). CONCLUSION: The Auto40 analyzer is an alternative flow cytometer for CD4 T lymphocyte enumeration to be used in routine for immunological monitoring according to the current WHO recommendations in HIV-infected adults as well as children living in resource-constrained settings like Chad.

The acute phase of Chikungunya virus infection in humans is associated with strong innate immunity and T CD8 cell activation.

BACKGROUND: Rapidly spreading to new regions, including the islands of the Indian Ocean, Central Africa, and Europe, Chikungunya fever is becoming a major problem of public health. Unlike other members of the alphavirus genus, immune responses to Chikungunya virus (CHIKV) have been poorly investigated. METHODS: We conducted a large ex vivo multiplex study of 50 cytokine, chemokine, and growth factor plasma profiles in 69 acutely infected patients from the Gabonese outbreak of 2007. We also assessed a phenotypic study of T lymphocyte responses during human acute CHIKV infection. RESULTS: CHIKV infection in humans elicited strong innate immunity involving the production of numerous proinflammatory mediators. Interestingly, high levels of Interferon (IFN) α were consistently found. Production of interleukin (IL) 4, IL-10, and IFN-γ suggested the engagement of the adaptive immunity. This was confirmed by flow cytometry of circulating T lymphocytes that showed a CD8+ T lymphocyte response in the early stages of the disease, and a CD4+ T lymphocyte mediated response in the later stages. For the first time to our knowledge, we found evidence of CD95-mediated apoptosis of CD4+ T lymphocytes during the first 2 days after symptoms onset, ex vivo. CONCLUSIONS: Together, our findings suggest that strong innate immunity is required to control CHIKV infection.

Acute dengue virus 2 infection in Gabonese patients is associated with an early innate immune response, including strong interferon alpha production.

BACKGROUND: Dengue is now a leading cause of morbidity and mortality throughout the tropics. We conducted the first ex vivo study of dengue fever (DF) in African patients infected during the first Gabonese dengue virus 2 (DENV-2) outbreak in 2007, in order to investigate cytokine production, including the antiviral cytokine IFN-α, reported to be a potent inhibitor of DENV replication in vitro. METHODS: Levels of 50 cytokines, chemokines and growth factors were measured in plasma from 36 patients with DENV-2 infection, and in uninfected controls, using Luminex multiplex technology. The results were interpreted according to the day of sampling after symptom onset. PBMC from six patients were also studied for T lymphocyte cell surface marker expression by flow cytometry. RESULTS: Acute DENV-2 infection elicited high levels of several pro-inflammatory cytokines (IL-6 and IL-17), chemokines (MIF, RANTES, IP-10 and MCP-1) and growth factors (G-CSF, GM-CSF and VEGF-A). We also observed high levels of IFN-α for the first time in adult DF patients, and CD4+ and CD8+ T cell activation at symptom onset. CONCLUSION: Acute DENV-2 infection in African patients elicits a strong innate response involving IFN-α production, as well as an adaptive immune response.

Concurrent chikungunya and dengue virus infections during simultaneous outbreaks, Gabon, 2007.

An outbreak of febrile illness occurred in Gabon in 2007, with 20,000 suspected cases. Chikungunya or dengue-2 virus infections were identified in 321 patients; 8 patients had documented co-infections. Aedes albopictus was identified as the principal vector for the transmission of both viruses.

Allele frequencies and haplotypes of eight Y-short tandem repeats in Bantu population living in Central Africa.

Eight Y chromosome short tandem repeats (STR) loci (DYS19, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS385I/II) were used to assess haplotype distribution in non-selected, unrelated Bantu males living in Central Africa [N. Mathias, M. Bayes, C. Tyler-Smith, Highly informative compound haplotypes for the human Y chromosome, Hum. Mol. Genet. 3 (1994) 115-123; L. Roewer, J. Arnemann, N.K. Spurr, K.H. Grzeschik, J.T. Epplen, Simple repeat sequences on the human Y chromosome are equally polymorphic as their autosomal counterparts, Hum. Genet. 89 (1992) 389-394; P. De Knijff, M. Kayser, A. Caglia, D. Corach, N. Fretwel, C. Gehrig, G. Graziosi, F. Heidorn, S. Herrmann, B. Herzog, M. Hidding, K. Honda, M. Jobling, M. Krawczak, K. Leim, S. Meuser, E. Meyer, W. Oesterreich, A. Pandya, W. Parson, G. Penacino, A. Perez-Lezaun, A. Piccini, M. Prinz, C. Schmitt, P. M. Schneider, R. Szibor, J. Teifel-Greding, G. Weishold, L. Rower, Chromosome Y microsatellites: population genetic and evolutionary aspects, Int. J. Legal Med. 110 (1997) 134-149; M. Kayser, A. Caglia, D. Corach, N. Fretwel, C. Gehrig, G. Graziosi, F. Heidorn, S. Herrmann, B. Herzog, M. Hidding, K. Honda, M. Jobling, M. Krawczak, K. Leim, S. Meuser, E. Meyer, W. Oesterreich, A. Pandya, W. Parson, G. Penacino, A. Perez-Lezaun, A. Piccini, M. Prinz, C. Schmitt, P. M. Schneider, R. Szibor, J. Teifel-Greding, G. Weishold, P. de Knijff, L. Rower, Evaluation of Y chromosome STRs: a multicenter study, Int. J. Legal Med. 110 (1997) 125-133, 141-149]. One hundred and sixty-five full haplotypes were obtained from Bantu males. The most common haplotype (DYS19-15, DYS389I-13, DYS389II-30, DYS390-21, DYS391-10, DYS392-11, DYS393-13, DYS385I/II-15,17) was shared by 5.5% of individuals. In the Bantu population in Central Africa, the haplotype diversity and the discrimination capacity of Y-STR may be estimated at 99.14% and 0.5333, respectively.

Genital shedding of herpes simplex virus type 2 in childbearing-aged and pregnant women living in Gabon.

The prevalence of genital shedding of herpes simplex virus (HSV)-2 and related risk factors was evaluated in a prospective population of 355 women attending the Maternity Joséphine Bongo, in Libreville, Gabon. We found a high prevalence (66%) of HSV-2 seropositivity, with a high proportion, 14%, of women harbouring HSV-2 DNA shedding in their genital secretions. HSV-2 genital shedding was positively associated with previous episodes of genital blisters, current genital ulcer, current genital blister, HIV seropositivity and HSV-2 seropositivity. The high prevalence of HSV-2 in childbearing-aged population indicates that young women living in Gabon are at high risk for HIV acquisition in HIV-seronegative women sexually exposed to HIV, for HIV transmission in HIV-infected women co-infected by HSV-2 and finally for HSV-2 vertical transmission during pregnancy.

High prevalence of high-risk oncogenic human papillomaviruses harboring atypical distribution in women of childbearing age living in Libreville, Gabon.

The extent of human papillomavirus (HPV) genital shedding and type-specific diversity were evaluated in 354 consecutive women of childbearing age living in Libreville, Gabon. Detection of HPV DNA was performed by PCR using the MY09/MY11 primer set on DNA extracted from endocervical swabs. All PCR positive specimens were subjected to direct sequencing and HPV genotypes were identified on the basis of >95% sequence homology in the L1 region. Reverse line blot hybridization assay was used when a genotype could not be resolved by sequencing alone. HPV DNA was detected in 163 (46%) women, all clinically asymptomatic for HPV-related lesions. The highest prevalence of genital HPV detection (45%) was in the age group from 22 to 29 years. A total of 90 women (55%) harbored high-risk (HR) genotypes, with the most common being HPV-53 (19; 12%), HPV-58 (17; 11%), and HPV-16 (16; 10%). Low-risk genotypes were found in 36 (22%) women with HPV-54 and HPV-70 being the most frequently detected (17; 11% and 10; 6%, respectively). Finally 37 women (23%) tested positive for genotypes of unknown oncogenic risk, the most common in this category being HPV-83 (20; 12%). Multiple infections were detected in 35 (21%) women. By multivariate analysis, HPV genital shedding was significantly associated with young age (OR: 0.34; P < 0.007). The multivalent vaccine currently available against cervical carcinomas, is only active against HPV-16 and HPV-18, and will thus have a low impact in this setting.

[Evaluation of a panel of commercial kits for the detection of serum HIV-specific antibodies, and choice of alternative strategies for the serological diagnosis in Libreville (Gabon)]. / Evaluation de trousses de dépistage de l'infection à VIH au Gabon.

Nine commercially available kits for the screening of serum antibodies to the human immunodeficiency virus (HIV) were evaluated with a panel of 170 serum samples from adults in Gabon. The reference procedures showed that 96 samples had no antibodies, while 74 produced antibodies to HIV-1 (n=72) or HIV-2 (n=2). The sensitivity for 2 kits was less than 99% and the specificity of 3 less than 95%. Based on the panel of Gabonese serum samples, 4 of the 9 kits met the World Health Organization (WHO) acceptability criteria: sensitivity greater than 99% and specificity greater than 95%. Three kits available in Gabon that met these criteria were finally retained: Determine HIV-1/2, Genscreen Plus HIV Ag-Ab, and Immunocomb II HIV1&2 BiSpot. Of 18 configurations of alternative diagnosis strategies for HIV infection with these three kits, some WHO strategy II configurations (2 sequential assays) and all the WHO strategy III configurations (3 sequential assays) provided the maximum accuracy in diagnosing HIV infection in Gabon (sensitivity, specificity, positive predictive value, negative predictive value of 100%). The configuration using the Determine HIV-1/2 kit as first screening assay, followed by Genscreen Plus HIV Ag-Ab as a confirmatory assay, and finally, Immunocomb II HIV1&2 BiSpot as the third assay to discriminate samples discordant with the two first assays, was best, with high accuracy and less expense. The configuration of the two sequential rapid assays, Immunocomb II HIV1&2 BiSpot followed by Determine HIV-1/2, was also very accurate and reliable, as well as easiest to carry out (no need for ELISA technology), but it was twice as expensive as the first configuration with three sequential kits. In conclusion, when the laboratory facilities are available, the sequential diagnostic strategy of two rapid assays and a combined ELISA assay constitutes the best configuration, in terms of both accuracy and cost. When laboratory facilities are unavailable, sequential use of two rapid assays constitutes a convenient and accurate configuration, but is much more expensive.