Examining 7 years of implementing quality management systems in medical laboratories in sub-Saharan Africa.

BACKGROUND: Achievement of ISO15189 accreditation demonstrates competency of a laboratory to conduct testing. Three programmes were developed to facilitate achievement of accreditation in low- and middle-income countries: Strengthening Laboratory Management Towards Accreditation (SLMTA), Stepwise Laboratory Improvement Process Towards Accreditation (SLIPTA) and Laboratory Quality Stepwise Implementation (LQSI). OBJECTIVE: To determine the level of accreditation and associated barriers and facilitators among medical laboratories in the WHO-AFRO region by 2020. METHODS: A desk review of SLIPTA and SLMTA databases was conducted to identify ISO15189-accredited medical laboratories between January 2013 and December 2020. Data on access to the LQSI tool were extracted from the WHO database. Facility and country characteristics were collected for analysis as possible enablers of accreditation. The chi-square test was used to analyse differences with level of significance set at <0.05. RESULTS: A total of 668 laboratories achieved accreditation by 2020 representing a 75% increase from the number in 2013. Accredited laboratories were mainly in South Africa (n = 396; 55%) and Kenya (n = 106; 16%), two countries with national accreditation bodies. About 16.9% (n = 113) of the accredited laboratories were registered for the SLIPTA programme and 26.6% (n = 178) for SLMTA. Approximately 58,217 LQSI users were registered by December 2020. Countries with a higher UHC index for access to HIV care and treatment, higher WHO JEE scores for laboratory networks, a larger number of registered LQSI users, with national laboratory policy/strategic plans and PEPFAR-priority countries were more likely to have an accredited laboratory. Of the 475 laboratories engaged in the SLIPTA programme, 154 attained ≥4 SLIPTA stars (ready to apply for accreditation) and 113 achieved ISO 15189 accreditation, with 96 enrolled into the SLMTA programme. Lower-tier laboratories were less likely to achieve accreditation than higher-tier laboratories (7.7% vs. 30%) (p < 0.001). The probability of achieving ISO 15189 accreditation (19%) was highest during the first 24 months after enrolment into the SLIPTA programme. CONCLUSION: To sustainably anchor quality improvement initiatives at facility level, national approaches including access to a national accreditation authority, adoption of national quality standards and regulatory frameworks are required.

First evidence for continuous circulation of hepatitis A virus subgenotype IIA in Central Africa.

Although a high seroprevalence of antibodies against hepatitis A virus (HAV) has been estimated in Central Africa, the current status of both HAV infections and seroprevalence of anti-HAV antibodies remains unclear due to a paucity of surveillance data available. We conducted a serological survey during 2015-2017 in Gabon, Central Africa, and confirmed a high seroprevalence of anti-HAV antibodies in all age groups. To identify the currently circulating HAV strains and to reveal the epidemiological and genetic characteristics of the virus, we conducted molecular surveillance in a total of 1007 patients presenting febrile illness. Through HAV detection and sequencing, we identified subgenotype IIA (HAV-IIA) infections in the country throughout the year. A significant prevalence trend emerged in the young child population, presenting several infection peaks which appeared to be unrelated to dry or rainy seasons. Whole-genome sequencing and phylogenetic analyses revealed local HAV-IIA evolutionary events in Central Africa, indicating the circulation of HAV-IIA strains of a region-specific lineage. Recombination analysis of complete genome sequences revealed potential recombination events in Gabonese HAV strains. Interestingly, Gabonese HAV-IIA possibly acquired the 5'-untranslated region (5'-UTR) of the rare subgenotype HAV-IIB in recent years, suggesting the present existence of HAV-IIB in Central Africa. These findings indicate a currently stable HAV-IIA circulation in Gabon, with a high risk of infections in children aged under 5 years. Our findings will enhance the understanding of the current status of HAV infections in Central Africa and provide new insight into the molecular epidemiology and evolution of HAV genotype II.

Ongoing evolution of hepatitis B virus during viremia in patients with febrile in Central Africa.

Hepatitis B virus (HBV) infection remains to be a major public health issue worldwide, although there is currently a safe vaccine and effective antiviral treatments. In surveillance of infectious diseases in Gabon, HBV viremia was detected in patients with febrile. Whole-genome sequencing was conducted to characterize the HBV strains currently circulating in Gabon and to investigate HBV genome diversity during viremia. Phylogenetic analysis revealed the existence of former subgenotype A5, which exhibits a particular pattern of distribution from several West and Central African countries to Haiti. Furthermore, sequencing analysis identified two similar HBV strains mixed in one sample, and a very rare 1-base pair insertion in the viral precore region. This insertion caused a frameshift mutation, indicating the production of an aberrant fusion protein of the HBV x and e antigens. Our data showed that the detected HBV strain was possibly in an "evolving" state during viremia, a phase of active replication.

In vitro growth of Plasmodium falciparum in neonatal blood.

BACKGROUND: Children below the age of six months suffer less often from malaria than older children in sub-Saharan Africa. This observation is commonly attributed to the persistence of foetal haemoglobin (HbF), which is considered not to permit growth of Plasmodium falciparum and therefore providing protection against malaria. Since this concept has recently been challenged, this study evaluated the effect of HbF erythrocytes and maternal plasma on in vitro parasite growth of P. falciparum in Central African Gabon. METHODS: Umbilical cord blood and peripheral maternal blood were collected at delivery at the Albert Schweitzer Hospital in Gabon. Respective erythrocyte suspension and plasma were used in parallel for in vitro culture. In vitro growth rates were compared between cultures supplemented with either maternal or cord erythrocytes. Plasma of maternal blood and cord blood was evaluated. Parasite growth rates were assessed by the standard HRP2-assay evaluating the increase of HRP2 concentration in Plasmodium culture. RESULTS: Culture of P. falciparum using foetal erythrocytes led to comparable growth rates (mean growth rate = 4.2, 95% CI: 3.5 - 5.0) as cultures with maternal red blood cells (mean growth rate =4.2, 95% CI: 3.4 - 5.0) and those from non-malaria exposed individuals (mean growth rate = 4.6, 95% CI: 3.8 - 5.5). Standard in vitro culture of P. falciparum supplemented with either maternal or foetal plasma showed both significantly lower growth rates than a positive control using non-malaria exposed donor plasma. CONCLUSIONS: These data challenge the concept of HbF serving as intrinsic inhibitor of P. falciparum growth in the first months of life. Erythrocytes containing HbF are equally permissive to P. falciparum growth in vitro. However, addition of maternal and cord plasma led to reduced in vitro growth which may translate to protection against clinical disease or show synergistic effects with HbF in vivo. Further studies are needed to elucidate the pathophysiology of innate and acquired protection against neonatal malaria.

Re-emergence of dengue virus serotype 3 infections in Gabon in 2016-2017, and evidence for the risk of repeated dengue virus infections.

OBJECTIVES: Dengue outbreaks, mainly caused by dengue virus serotype 2 (DENV-2), occurred in 2007 and in 2010 in Gabon, Central Africa. However, information on DENV infections has been insufficient since 2010. The aim of this study was to investigate the current DENV infection scenario and the risk of repeated infections in Gabon. METHODS: During 2015-2017, serum samples were collected from enrolled febrile participants and were tested for DENV infection using RT-qPCR. DENV-positive samples were analyzed for a history of previous DENV infection(s) using ELISA. The complete DENV genome was sequenced to analyze the phylogeny of Gabonese DENV strains. RESULTS: DENV-3 was exclusively detected, with a high rate of anti-DENV IgG seropositivity among DENV-3-positive participants. DENV-3 showed higher infection rates in adults and the infection was seasonal with peaks in the rainy seasons. Phylogenetic analysis revealed that Gabonese DENV-3 originated from West African strains and has been circulating continuously in Gabon since at least 2010, when the first DENV-3 case was reported. CONCLUSIONS: These findings indicate stable DENV-3 circulation and the risk of repeated DENV infections in Gabon, highlighting the need for continuous monitoring to control DENV infections.

Effect of immune regulatory pathways after immunization with GMZ2 malaria vaccine candidate in healthy lifelong malaria-exposed adults.

BACKGROUND: Despite appreciable immunogenicity in malaria-naive populations, many candidate malaria vaccines are considerably less immunogenic in malaria-exposed populations. This could reflect induction of immune regulatory mechanisms involving Human Leukocyte Antigen G (HLA-G), regulatory T (Treg), and regulatory B (Breg) cells. Here, we addressed the question whether there is correlation between these immune regulatory pathways and both plasmablast frequencies and vaccine-specific IgG concentrations. METHODS: Fifty Gabonese adults with lifelong exposure to Plasmodium spp were randomized to receive three doses of either 30 µg or 100 µg GMZ2-CAF01, or 100 µg GMZ2-alum, or control vaccine (rabies vaccine) at 4-week intervals. Only plasma and peripheral blood mononuclear cells isolated from blood samples collected before (D0) and 28 days after the third vaccination (D84) of 35 participants were used to measure sHLA-G levels and anti-GMZ2 IgG concentrations, and to quantify Treg, Breg and plasmablast cells. Vaccine efficacy was assessed using controlled human malaria infection (CHMI) by direct venous inoculation of Plasmodium falciparum sporozoites (PfSPZ Challenge). RESULTS: The sHLA-G concentration increased from D0 to D84 in all GMZ2 vaccinated participants and in the control group, whereas Treg frequencies increased only in those receiving 30 µg or 100 µg GMZ2-CAF01. The sHLA-G level on D84 was associated with a decrease of the anti-GMZ2 IgG concentration, whereas Treg frequencies on D0 or on D84, and Breg frequency on D84 were associated with lower plasmablast frequencies. Importantly, having a D84:D0 ratio of sHLA-G above the median was associated with an increased risk of P. falciparum infection after sporozoites injection. CONCLUSION: Regulatory immune responses are induced following immunization. Stronger sHLA-G and Treg immune responses may suppress vaccine induced immune responses, and the magnitude of the sHLA-G response increased the risk of Plasmodium falciparum infection after CHMI. These findings could have implications for the design and testing of malaria vaccine candidates in semi-immune individuals.

Tuberculosis Treatment Outcome and Drug Resistance in Lambaréné, Gabon: A Prospective Cohort Study.

Despite overall global progress in tuberculosis (TB) control, TB remains one of the deadliest communicable diseases. This study prospectively assessed TB epidemiology in Lambaréné, Gabon, a Central African country ranking 10th in terms of TB incidence rate in the 2014 World Health Organization TB report. In Lambaréné, between 2012 and 2014, 201 adult and pediatric TB patients were enrolled and followed up; 66% had bacteriologically confirmed TB and 95% had pulmonary TB. The human immunodeficiency virus (HIV) coinfection rate was 42% in adults and 16% in children. Mycobacterium tuberculosis and Mycobacterium africanum were identified in 82% and 16% of 108 culture-confirmed TB cases, respectively. Isoniazid (INH) and streptomycin yielded the highest resistance rates (13% and 12%, respectively). The multidrug resistant TB (MDR-TB) rate was 4/91 (4%) and 4/13 (31%) in new and retreatment TB cases, respectively. Treatment success was achieved in 53% of patients. In TB/HIV coinfected patients, mortality rate was 25%. In this setting, TB epidemiology is characterized by a high rate of TB/HIV coinfection and low treatment success rates. MDR-TB is a major public health concern; the need to step-up in-country diagnostic capacity for culture and drug susceptibility testing as well as access to second-line TB drugs urgently requires action.

Modulation of the complement system in monocytes contributes to tuberculosis-associated immune reconstitution inflammatory syndrome.

OBJECTIVE: Tuberculosis-associated immune reconstitution inflammatory syndrome (TB-IRIS) is a common complication in HIV-TB co-infected patients receiving combined antiretroviral therapy (cART). This study investigated a putative contribution of monocytes to the development of TB-IRIS. DESIGN: A prospective study was designed to compare gene expression between patients who developed TB-IRIS with matched non-TB-IRIS controls. METHODS: We performed a hypothesis-generating transcriptome analysis on monocytes of HIV-TB co-infected patients. Identified pathways were subsequently analysed in patients' monocytes before and shortly after cART initiation, in a technically independent set-up (nCounter). Additionally, protein expression and enzymatic activities of specific factors were assessed at the systemic level. RESULTS: Pathway analysis of microarray datasets and focused gene expression study revealed that, even before initiation of cART, the complement system is dysregulated in HIV-TB co-infected patients who are predisposed to developing TB-IRIS. Detailed analysis revealed differences between TB-IRIS patients and matched non-TB-IRIS cases, at the level of the balance between the effector C1Q and the inhibitor C1-INH, both before and 2 weeks after cART initiation. These differences were mirrored by increases in the downstream pro-inflammatory complement factor C5 over the course of 2 weeks of cART. Our results suggest that inappropriate control of complement activation could be associated with the 'flaring up' of inflammation observed during TB-IRIS. CONCLUSION: The current study reveals a contribution of monocytes and the complement system to TB-IRIS development. An intriguing possibility is that the development of TB-IRIS may depend partially on the relative balance between C1Q and C1-INH.