Spreading of SARS-CoV-2 in West Africa and assessment of risk factors.

Although the African continent is, for the moment, less impacted than the rest of the world, it still faces the risk of a spread of COVID-19. In this study, we have conducted a systematic review of the information available in the literature in order to provide an overview of the epidemiological and clinical features of COVID-19 pandemic in West Africa and of the impact of risk factors such as comorbidities, climatic conditions and demography on the pandemic. Burkina Faso is used as a case study to better describe the situation in West Africa. The epidemiological situation of COVID-19 in West Africa is marked by a continuous increase in the numbers of confirmed cases. This geographic area had on 29 July 2020, 131 049 confirmed cases by polymerase chain reaction, 88 305 recoveries and 2102 deaths. Several factors may influence the SARS-CoV-2 circulation in Africa: (i) comorbidities: diabetes mellitus and high blood pressure could lead to an increase in the number of severe cases of SARS-CoV-2; (ii) climatic factors: the high temperatures could be a factor contributing to slow the spread of the virus and (iii) demography: the West Africa population is very young and this could be a factor limiting the occurrence of severe forms of SARS-CoV-2 infection. Although the spread of the SARS-CoV-2 epidemic in West Africa is relatively slow compared to European countries, vigilance must remain. Difficulties in access to diagnostic tests, lack of hospital equipment, but also the large number of people working in the informal sector (such as trading, businesses, transport and restoration) makes it difficult to apply preventive measures, namely physical distancing and containment.

Detection of SARS-CoV-2 antibodies using commercial assays and seroconversion patterns in hospitalized patients.

OBJECTIVES: SARS-CoV-2 antibody assays are needed for serological surveys and as a complement to molecular tests to confirm COVID-19. However, the kinetics of the humoral response against SARS-CoV-2 remains poorly described and relies on the performance of the different serological tests. METHODS: In this study, we evaluated the performance of six CE-marked point-of-care tests (POC) and three ELISA assays for the diagnosis of COVID-19 by exploring seroconversions in hospitalized patients who tested positive for SARS-CoV-2 RNA. RESULTS: Both the ELISA and POC tests were able to detect SARS-CoV-2 antibodies in at least half of the samples collected seven days or more after the onset of symptoms. After 15 days, the rate of detection rose to over 80% but without reaching 100%, irrespective of the test used. More than 90% of the samples collected after 15 days tested positive using the iSIA and Accu-Tell® POC tests and the ID.Vet IgG ELISA assay. Seroconversion was observed 5 to 12 days after the onset of symptoms. Three assays suffer from a specificity below 90% (EUROIMMUN IgG and IgA, UNscience, Zhuhai Livzon). CONCLUSIONS: The second week of COVID-19 seems to be the best period for assessing the sensitivity of commercial serological assays. To achieve an early diagnosis of COVID-19 based on antibody detection, a dual challenge must be met: the immunodiagnostic window period must be shortened and an optimal specificity must be conserved.

Usutu virus: A new threat?

Usutu virus (USUV) is an emerging arbovirus that was first isolated in South Africa in 1959. This Flavivirus is maintained in the environment through a typical enzootic cycle involving mosquitoes and birds. USUV has spread to a large part of the European continent over the two decades mainly leading to substantial avian mortalities with a significant recrudescence of bird infections recorded throughout Europe within the few last years. USUV infection in humans is considered to be most often asymptomatic or to cause mild clinical signs. Nonetheless, a few cases of neurological complications such as encephalitis or meningoencephalitis have been reported. USUV and West Nile virus (WNV) share many features, like a close phylogenetic relatedness and a similar ecology, with co-circulation frequently observed in nature. However, USUV has been much less studied and in-depth comparisons of the biology of these viruses are yet rare. In this review, we discuss the main body of knowledge regarding USUV and compare it with the literature on WNV, addressing in particular virological and clinical aspects, and pointing data gaps.

Detection of Mycobacterium tuberculosis in paucibacillary sputum: performances of the Xpert MTB/RIF ultra compared to the Xpert MTB/RIF, and IS6110 PCR.

The Xpert MTB/RIF Ultra assay has recently been launched to improve the detection of smear negative disease. This retrospective study compares the sensitivity of Xpert MTB/RIF Ultra with that of Xpert MTB/RIF tests and IS6110 real-time PCR in sputum. Diagnostic performance of three molecular tests was evaluated using 48 culture-positive clinical respiratory specimens diluted to obtain paucibacillary sputum specimens. Xpert MTB/RIF Ultra had the highest sensitivity of 100% compared to 42% (P < 0.001) for Xpert MTB/RIF and 64.5% (P = 0.02) for IS6110-PCR. All "very low" or "low" positive specimens using Xpert MTB/RIF Ultra were tested positive using IS6110-PCR, but 35.4% were found negative using Xpert MTB/RIF. Xpert MTB/RIF Ultra is more sensitive than the two other tests for sputum with a low bacterial load. Adding detection of IS6110 and IS1081 to rpoB, is a key evolution of the assay and improves the detection of Mycobacterium tuberculosis' DNA in paucibacillary sputum.

Association between breast milk fatty acids and HIV-1 transmission through breastfeeding.

A residual mother-to-child transmission of HIV through breastfeeding persists despite prophylaxis. We identified breast milk fatty acids (FA) associated with postnatal HIV transmission through breastfeeding in a case-control study. Cases (n=23) were HIV-infected women with an infant who acquired HIV after 6 weeks of age. Controls (n=23) were matched on infant׳s age at sample collection. Adjusting for maternal antenatal plasma CD4 T cell count, cis-vaccenic acid (18:1n-7) and eicosatrienoic acid (20:3n-3) were associated with HIV transmission in opposite dose-response manner: OR (tertile 3 versus tertile 1): 10.8 and 0.16, p for trend=0.02 and 0.03, respectively. These fatty acids correlated with HIV RNA load, T helper-1 related cytokines, IL15, IP10, and ß2 microglobulin, positively for cis-vaccenic acid, negatively for eicosatrienoic acid. These results suggested a change in FA synthesis by mammary gland cells leading to increased cis-vaccenic acid in milk of mothers who transmitted HIV to their infant during breastfeeding.

Developmental determinants in non-communicable chronic diseases and ageing.

Prenatal and peri-natal events play a fundamental role in health, development of diseases and ageing (Developmental Origins of Health and Disease (DOHaD)). Research on the determinants of active and healthy ageing is a priority to: (i) inform strategies for reducing societal and individual costs of an ageing population and (ii) develop effective novel prevention strategies. It is important to compare the trajectories of respiratory diseases with those of other chronic diseases.

24-Month adherence, tolerance and efficacy of once-a-day antiretroviral therapy with didanosine, lamivudine, and efavirenz in African HIV-1 infected children: ANRS 12103/12167.

BACKGROUND: There is no data on long-term benefit of once-a-day antiretroviral therapy (ART) with combination of DDI, 3TC and EFV to allow its use in future therapeutic strategies. OBJECTIVES: To assess 24-month immuno-virological, adherence, tolerance, and effectiveness of a once-a-day ART with DDI, 3TC and EFV. METHODS: A phase 2 open trial including 51 children aged from 30 months to 15 years, monitored a once-a-day regimen for 24 months from 2006 to 2008 in the Departement de Pediatrie du CHUSS, at Bobo-Dioulasso in Burkina Faso. We tested immunological and virological response, adherence, tolerance and resistance of the treatment. RESULTS: Children with CD4 >25% at 24 months were 67.4% (33/49) CI 95% [54%, 80%]. The proportion of children with viral plasma RNA <300 cp / ml at 24 months of treatment was 81.6 % (40/49) CI [68.0% 91.2%]. Good adherence was obtained with more than 88% adherence > 95% over the 24 months. Drugs were well tolerated. CONCLUSIONS: Given the limited number of antiretroviral drugs available in Africa and the inadequacy of laboratory monitoring in support program, once-a-day treatment and especially the DDI-based combination strategies could be an attractive operational option.

[Determinants of low birth weight among newborns to HIV-infected mothers not eligible for antiretroviral treatment in Africa]. / Déterminants du faible poids de naissance chez des enfants nés de mères séropositives pour le VIH, non éligibles au traitement antirétroviral, en Afrique.

BACKGROUND: Low birth weight (LBW) increases the risk of infant death, but little is known about its rate and determinants among babies born to HIV-infected mothers in sub-Saharan Africa. METHODS: This study was conducted in South Africa, Burkina Faso, Uganda and Zambia, during the recruitment process of the PROMISE-PEP (ANRS 12174) clinical trial. The study sample included 1196 subjects screened between August 2009 and December 2011, respectively 254 in South Africa, 221 in Burkina Faso, 197 in Uganda and 524 in Zambia, all ineligible for antiretroviral therapy. Data were collected during ANRS12174 clinical trial antenatal and postnatal screening visits, and during an inclusion visit for completion of an electronic case report form (eCRF). RESULTS: The mean (±SD) age of mothers was 27±5years and their mean CD4 count was 576±195cells/µL. Most mothers lived in a couple (78.7%), had no employment (72.3%) and had a good level of education (74% had gone to school). Male newborns predominated (51.7%). The mean birth weight was 3043g±435g, and 7.8% ([95%CI: 6.3%-9.3%]) of newborns weighed less than 2500g. In univariate analyses, being married or cohabiting, body mass index, WHO HIV disease stage II, female newborn and low gestational age were associated with risk of LBW. In multivariate regression model, low gestational age (aOR=3.74, P<0.0001) and female newborn (aOR=1.63, P=0.04) were significantly associated with LBW. CONCLUSION: The risk factors for LBW found in HIV-infected women ineligible for antiretroviral therapy were the same as in the general population. There was no evidence of additional risk factors associated with HIV infection.

Combining rapid diagnostic tests and dried blood spot assays for point-of-care testing of human immunodeficiency virus, hepatitis B and hepatitis C infections in Burkina Faso, West Africa.

People screened for human immunodeficiency virus (HIV) using rapid diagnostic tests (RDTs) in Africa remain generally unaware of their status for hepatitis B (HBV) and hepatitis C (HCV) infections. We evaluated a two-step screening strategy in Burkina Faso, using both HIV RDTs and Dried Blood Spot (DBS) assays to confirm an HIV-positive test, and to test for HBV and HCV infections. HIV counselling and point-of-care testing were performed at a voluntary counselling and testing centre with HBV, HCV status and HIV confirmation using DBS specimens, being assessed at a central laboratory. Serological testing on plasma was used as the reference standard assay to control for the performance of DBS assays. Nineteen out of 218 participants included in the study were positive for HIV using RDTs. A fourth-generation HIV ELISA and immunoblot assays on DBS confirmed HIV status. Twenty-four out of 25 participants infected with HBV were found positive for hepatitis B surface antigen (HBsAg) using DBS. One sample with a low HBsAg concentration on plasma was not detected on DBS. Five participants tested positive for HCV antibodies were confirmed positive with an immunoblot assay using DBS specimens. Laboratory results were communicated within 7 days to participants with no loss to follow up of participants between the first and second post-test counselling sessions. In conclusion, DBS collection during HIV point-of-care testing enables screening and confirmation of HBV, HCV and HIV infections. Diagnosis using DBS may assist with implementation of national programmes for HBV, HCV and HIV screening and clinical care in middle- to low-income countries.

Long-term hepatitis B virus surface antigen decay in HIV-1/hepatitis B virus-coinfected adults initiating a tenofovir-containing regimen.

Hepatitis B virus (HBV) surface antigen (HBsAg) decay was explored in HIV-1- and HBV-coinfected patients beginning antiretroviral (ARV) therapy containing tenofovir disoproxil fumarate (TDF). The mean HBsAg decay was 0.38 log(10) IU/ml/year (95% confidence interval [CI], 0.71 to 0.05) in 18 patients with sustained plasma HIV-1 RNA suppression and 0.15 log(10) IU/ml/year (0.21 to 0.09) in 12 patients experiencing HIV-1 virologic failure due to suboptimal adherence to ARV (P = 0.17). We estimated that six of these 18 patients will attain HBsAg values below 10 IU/ml after 10 years of treatment.

Intrafamilial cluster of pulmonary tuberculosis due to Mycobacterium bovis of the African 1 clonal complex.

A new clonal complex of Mycobacterium bovis present at high frequency in cattle from west central African countries has been described as the African 1 (Af1) clonal complex. Here, the first intrafamilial cluster of human tuberculosis cases due to M. bovis Af1 clonal complex strains is reported. We discuss hypotheses regarding modes of transmission.

Pulmonary tuberculosis due to Mycobacterium microti: a study of six recent cases in France.

Human tuberculosis caused by Mycobacterium microti is rare, but its prevalence and clinical significance may have been underestimated. To the best of our knowledge, 21 cases have been reported in the literature in the last decade. We report six recent pulmonary cases caused by M. microti over a period of 5 years detected in French clinical mycobacteriology laboratories of the hospital network. Our data confirm the potential of M. microti to cause clinical illness in immunocompetent patients. M. microti grew slowly from specimens, delaying the final microbiological diagnosis. Therefore, patients with tuberculosis caused by M. microti could benefit from the use of rapid diagnostic molecular techniques directly on clinical samples. From a review of the literature and this study, a classical antituberculous therapy seems effective in treating patients with M. microti disease.

Highly structured genetic diversity of the Mycobacterium tuberculosis population in Djibouti.

Djibouti is an East African country with a high tuberculosis incidence. This study was conducted over a 2-month period in Djibouti, during which 62 consecutive patients with pulmonary tuberculosis (TB) were included. Genetic characterization of Mycobacterium tuberculosis, using mycobacterial interspersed repetitive-unit variable-number tandem-repeat typing and spoligotyping, was performed. The genetic and phylogenetic analysis revealed only three major families (Central Asian, East African Indian and T). The high diversity and linkage disequilibrium within each family suggest a long period of clonal evolution. A Bayesian approach shows that the phylogenetic structure observed in our sample of 62 isolates is very likely to be representative of the phylogenetic structure of the M. tuberculosis population in the total number of TB cases.

Comprehensive proteomic analysis of the human milk proteome: contribution of protein fractionation.

In-depth analysis of the milk proteome by mass spectrometry is challenged by the presence of few high-abundance proteins that interfere with the detection of lower-abundance proteins. Here, we evaluated the proteomic analysis of milk samples following a strong anion exchange fractionation procedure using denaturating conditions ensuring the disruption of protein-protein interactions. Crude whey or skim milk and their different resulting fractions were analyzed by protein chip array mass spectrometry. Using protein chip array mass spectrometry, several high-abundance proteins were localized in distinct fractions increasing the total number of unique peptides and proteins detected. This total number increased by about 20-30% by combining different chromatographic surface arrays used for capture. Reproducible results were obtained in human skim milk and whey; however this approach was not successful with milk fat globule membrane and required refinement. Hence, milk profiling by anion exchange fractionation combined to protein chip array mass spectrometry represents a promising tool to detect unknown low-abundance milk proteins that may ultimately prove useful as biomarkers of diseases transmitted by breastfeeding.

Effect of HIV-1 and antiretroviral therapy on herpes simplex virus type 2: a prospective study in African women.

OBJECTIVES: To document the natural history of herpes simplex virus type 2 (HSV-2) in relation to HIV and highly active antiretroviral therapy (HAART) in Africa, a longitudinal study was conducted of women in the placebo arms of two randomised controlled trials of HSV-suppressive therapy in Burkina Faso. METHODS: 22 HIV-uninfected women (group 1), 30 HIV-1-infected women taking HAART (group 2), and 68 HIV-1-infected women not eligible for HAART (group 3) were followed over 24 weeks. HSV-2 DNA was detected on alternate weeks using real-time PCR from cervicovaginal lavages. Plasma HIV-1 RNA was measured every month. CD4 cell counts were measured at enrollment. RESULTS: Ulcers occurred on 1.9%, 3.1% and 7.2% of visits in groups 1, 2 and 3 (p = 0.02). Cervicovaginal HSV-2 DNA was detected in 45.5%, 63.3% and 67.6% of women (p = 0.11), and on 4.3%, 9.7% and 15.5% of visits in the three groups (p<0.001). Among HIV-infected women, cervicovaginal HSV-2 DNA was detected more frequently during ulcer episodes (adjusted risk ratio (aRR) 2.79, 95% CI 2.01 to 3.86) and less frequently among women practising vaginal douching (aRR 0.60, 95% CI 0.40 to 0.91). Compared with women not taking HAART and with CD4 cell counts of 500 cells/microl or greater, women on HAART had a similar risk of HSV-2 shedding (aRR 0.95, 95% CI 0.52 to 1.73), whereas women with CD4 cell counts of 200-500 cells/microl were more likely to shed HSV-2 (aRR 1.71, 95% CI 1.02 to 2.86). CONCLUSIONS: HSV-2 reactivations occur more frequently among HIV-infected women, particularly those with low CD4 cell counts, and are only partly reduced by HAART. HSV therapy may benefit HIV-infected individuals during HAART.

Roles of clinical and subclinical reactivated herpes simplex virus type 2 infection and human immunodeficiency virus type 1 (HIV-1)-induced immunosuppression on genital and plasma HIV-1 levels.

BACKGROUND: Few longitudinal studies have described the interactions between reactivation of herpes simplex virus type 2 (HSV-2) infection (hereafter, "HSV-2 reactivation") and genital and systemic replication of human immunodeficiency virus type 1 (HIV-1). METHODS: Women in Burkina Faso who were seropositive for both HIV-1 and HSV-2 were enrolled in a randomized placebo-controlled trial of therapy to suppress reactivation of HSV-2 infection (hereafter, "HSV suppressive therapy"). During the baseline phase, 6 enriched cervicovaginal lavage specimens were obtained over 12 weeks to detect and quantify the HIV-1 RNA and HSV-2 DNA loads. RESULTS: Women with genital ulcer disease (GUD) detected at least once were more likely than women in whom GUD was not detected (risk ratio [RR], 1.23; 95% confidence interval [CI], 1.09-1.37) to have genital HIV-1 RNA detected during >or=1 visit. Similarly, women with genital HSV-2 DNA detected during >or=1 clinic visit were more likely than women in whom genital HSV-2 DNA was not detected (RR, 1.17; 95% CI, 1.01-1.34) to have genital HIV-1 RNA detected at least once. In addition, the mean genital HIV-1 RNA loads for women with GUD detected during >or=1 visit and women with HSV-2 genital shedding detected during >or=1 visit were greater than that for women in whom genital HSV-2 DNA or GUD was never detected. The plasma HIV-1 RNA load was increased among women for whom >or=1 visit revealed GUD (+0.25 log(10) copies/mL; 95% CI, -0.05-0.55) or genital HSV-2 DNA (+0.40 log(10) copies/mL; 95% CI, 0.15-0.66), compared with women who did not experience GUD or HSV-2 genital shedding, respectively. The association of HSV-2 reactivations on HIV-1 replication tended to be stronger in patients with a higher CD4(+) cell count (i.e., >500 cells/microL). The contribution of HSV-2 to HIV-1 replication among women with CD4(+) cell count of 500 cells/microL deserves further investigation. CLINICAL TRIALS REGISTRATION: The ANRS 1285 Study is registered with the National Institutes of Health (registration number NCT00158509).

Longitudinal effect following initiation of highly active antiretroviral therapy on plasma and cervico-vaginal HIV-1 RNA among women in Burkina Faso.

BACKGROUND: Highly active antiretroviral therapy (HAART) could decrease HIV-1 transmissibility by reducing genital and plasma HIV-1 RNA. METHODS: We evaluated the effect of HAART on genital and plasma HIV-1 RNA in a cohort of 39 antiretroviral-naïve women in Burkina Faso. Cervico-vaginal lavages were collected before HAART initiation and at six visits over 28 weeks while on HAART. Blood samples were collected at baseline and at three and four visits for CD4 and plasma HIV-1 RNA measurements, respectively. RESULTS: Before HAART, 72% of women had detectable genital HIV-1 RNA. After 18 weeks on HAART, only one woman (2.5%) had detectable plasma HIV-1 RNA and two women (5.1%) had detectable genital HIV-1 RNA. Similar results were observed at each follow-up visit. However, 16/34 (47%) women with consistently undetectable plasma HIV-1 RNA shed HIV-1 at least once between weeks 18 and 28. In samples with detectable genital HIV-1, the mean quantity of HIV-1 RNA decreased from 3.87 prior to HAART to 3.04 log(10) copies/mL at last visit (median 29 weeks; a 6.8-fold decrease in absolute number of copies/mL) (p = 0.04). A significant median CD4 lymphocyte cell gain of 121 cells/muL (interquartile range 59 to 204) was measured between pre-HAART and last visit. CONCLUSION: These findings suggest that HAART could play a role in reducing HIV transmission in Africa; however, they underscore the need to emphasise safe sex practices with patients taking HAART.

First molecular epidemiology study of Mycobacterium tuberculosis in Burkina Faso.

We conducted a molecular epidemiology study on 120 Mycobacterium tuberculosis isolates from patients presenting pulmonary tuberculosis (TB) in Burkina Faso. Classical antibiogram studies and genetic characterization, using mycobacterial interspersed repetitive-unit-variable-number tandem-repeat (MIRU-VNTR) typing and spoligotyping, were applied after culture. Molecular analysis of specific signatures showed that all TB cases reported in this study were caused by M. tuberculosis and identified no Mycobacterium bovis or Mycobacterium africanum isolates. This result is unexpected, as M. africanum strains were reportedly the etiologic agent in 20% of TB cases 2 decades ago. The comparison of spoligotypes from Burkina Faso with an international spoligotype database (SpolDB4) showed that the majority of isolates belong to major clades of M. tuberculosis (Haarlem, 9%; Latin American-Mediterranean, 30%; and T, 20%). The predominant group of isolates (30%) corresponds to spoligotype 61, described in Cameroon as the "Cameroon family." In Burkina Faso, as in Cameroon, this family could be associated with recent transmission of TB, suggesting a recent expansion in West Africa. Our data suggest a low level of primary drug resistance that may be a positive result of the Directly Observed Therapy Shortcourse program. Besides, based on spoligotyping plus MIRU-VNTR, data showed a high number of clusters in our sample, suggesting a high level of recent TB transmission in Burkina Faso. Nevertheless, an important genetic polymorphism was observed in this country, reflecting an endemicity situation where the control of TB would have less impact in the main towns.