High prevalence of human T-cell leukemia virus type-1b genotype among blood donors in Gabon, Central Africa.

BACKGROUND: The African continent is considered to be the largest endemic area of HTLV-1 infection, with at least several million infected individuals. Systematic screening of blood donors can prevent the transmission of HTLV-1 in blood. Gabon is one of the countries with the highest prevalence of HTLV-1 worldwide, and yet the routine testing of blood donors has still not been introduced. METHODS: All blood donations collected between April and July 2017 at the Centre National de Transfusion Sanguine of Gabon were studied. Plasma samples were screened by ELISA for the presence of HTLV-1/2 antibodies. Western blot (WB) and polymerase chain reaction (PCR) tests were used for confirmation. RESULTS: In total, 3123 blood donors were tested, including 1740 repeat and 1378 first-time blood donors (FTBDs). Of them, 132 samples tested positive for HTLV-1/2 by ELISA (4.2%). WB and PCR confirmed HTLV-1 infection for 23 individuals. The overall prevalence of HTLV-1 was 0.74% [95% CI 0.47%-1.10%], 1% in FTBD, and 0.5% in repeat donors. Age and sex-adjusted prevalence was five-fold lower in FTBD than in the general adult population of rural areas of Gabon. All detected HTLV-1 strains belonged to the central African HTLV-1b genotype but were highly diverse. CONCLUSION: We report an overall prevalence of HTLV-1 of 0.74%, one of the highest values reported for blood donors in Africa. Given the high risk of HTLV-1 transmission in blood, it is necessary to conduct cost-effectiveness studies to determine the need and feasibility of implementing screening of HTLV-1 in blood donors in Gabon.

Assessment of rapid diagnostic tests and fourth-generation Enzyme-Linked Immunosorbent Assays in the screening of Human Immunodeficiency and Hepatitis B virus infections among first-time blood donors in Libreville (Gabon).

BACKGROUND: Blood transfusion is a pathway for the transmission of blood-borne pathogens such as human immunodeficiency virus (HIV) and hepatitis B virus (HBV) from donors to recipients in most countries in sub-Saharan Africa, including Gabon. The study aimed to compare the performance of four rapid diagnostic tests (RDTs: Alere DETERMINE, BIOSYNEX Exacto Pro HIV, MEDIFF HIV 1&2, and BIOSYNEX IMMUNOQUICK HBsAg) with results of 4th-generation immunoenzymatic assays COBAS 6000 e601 and EVOLIS BioRad for the detection of HIV and hepatitis B surface antigen (HBsAg) in blood donors in Libreville, Gabon. METHODS: Reactive and nonreactive blood samples for HIV and HBsAg were selected using fourth-generation ELISA COBAS 6000 e601 and EVOLIS BioRad. The sensitivities of RDTs were calculated using Epi Info version 6.04dfr (CDC, Atlanta, USA). RESULTS: Sensitivities for the detection of HIV in blood donors were 90.9% for Alere DETERMINE, 81.8% for BIOSYNEX Exacto Pro HIV, and 81.8% for MEDIFF HIV 1&2 Serum/sang Total Cassette compared with COBAS 6000 e601. The sensitivity of Alere DETERMINE compared to the semi-automated ELISA Bio-Rad for HIV detection was 65.6%. The sensitivity of BIOSYNEX IMMUNOQUICK HBsAg compared to ELISA tests for the detection of HBsAg was 78.0%. The specificity of all RDTs for the detection of HIV and HBsAg was 100%. CONCLUSION: Alere DETERMINE HIV-1/2, MEDIFF HIV 1&2 Serum/sang Total Cassette, BIOSYNEX Exacto Pro HIV, and BIOSYNEX IMMUNOQUICK HBsAg are not recommended for determining whether donors qualify to donate blood because of their low sensitivity for the detection of HIV antibodies and HBsAg in blood donors in Gabon.

Prevalent hepatitis B surface antigen among first-time blood donors in Gabon.

Despite chronic Hepatitis B virus (HBV) infection being the main cause of younger-onset complex liver disease including cirrhosis and hepatocellular carcinoma (HCC) in Africa, very little is known regarding the seroprevalence of HBV in the Gabonese general population. This investigation aimed to provide strong epidemiological data and risk factors associated with HBV infection in first-time blood donors representative of the urban adult population. The screening of HBsAg was carried out using 4th generation ELISA kits. The overall seroprevalence of HBsAg was 7.28%. The frequency of HBsAg was differential and marked by annual variations in blood donors from 2009 to 2016. Seroprevalence was 2-fold higher among males versus females (OR = 1.90 (95% CI: 1.75-2.06), P<0.001). HBsAg seroprevalence was significantly higher in donors of the age group 25-35 years old compared to donors of the age group <18 years (OR = 1.64 (95% CI: 1.03-2.60), P = 0.04). The seroprevalence of HBsAg in family/replacement donors (FRD) was significantly higher than that of voluntary non-remunerated donors (VNRD) (OR = 0.88 (95% CI: 0.83-0.94), P <0.001). The simultaneous comparison of HBsAg seroprevalence with blood donation type, gender and age showed that the higher prevalence in FRD was significant only in males between 18 and 45 years and in females between 25 and 34 years of age. This study confirms the high endemicity of HBV in Gabon while identifying the most infected age groups for both men and women.

The risk of transfusion-transmitted viral infections at the Gabonese National Blood Transfusion Centre.

BACKGROUND: Blood transfusions carry the risk of transmitting blood-borne infections. In contrast to the situation in the developed world, there is a limited number of studies examining this problem in sub-Saharan Africa. In this study we aimed to calculate the risks of acquiring human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) infection from units of blood issued by the Gabonese Blood Transfusion Centre between 2009 and 2011. MATERIALS AND METHODS: All the donations were tested for infectious diseases and the seroconversion incidence rates of HIV, HBV and HCV were calculated. The residual risk of transfusion-associated transmission for each virus was calculated by multiplying the seroconversion rates by the window period expressed in fractions of a year. RESULTS: The risks of becoming infected with HIV, HCV, and HBV in subjects receiving units of blood from the Gabonese Blood Transfusion Centre were 64.7, 207.94 and 534.53 per million donations, respectively. CONCLUSIONS: This study, which is the first to quantify the true risks of transfusion-transmitted infections in Gabon, reveals and confirms the need to reinforce preventative and screening strategies to improve transfusion safety in sub-Saharan Africa.

Comparison of electrochemiluminescence and ELISA methods in the detection of blood borne pathogens in Gabon

Objective:To assess the performances of Cobas 6000 e601 and EVOLIS BioRad in the detection of HIV,HBV and HCV in blood donors in Libreville (Gabon).Methods:A cross-sectional investigation was conducted in July 2017 in a total of 2 000 blood donors recruited at the National Blood transfusion Center,Libreville Gabon.Among them,363 donors were selected to compare the performances of COBAS 6000 e601 (electro-chemiluminescence) and EVOLIS BioRad in detecting HIV,HBV and HCV using Cohen's kappa coefficient.Results:Both methods yielded similar results for the detection of HIV and HBsAg.A very good agreement of 93.39％ and an excellent agreement of 98.90％ were obtained for the detection of HIV and HbsAg,with kappa values of 0.80 and 0.98,respectively.The observed agreement of 91.86％ was found for the detection of HCV,which gave a fair agreement between the two methods with kappa =0.33.Conclusions:The two evaluation methods showed a similar performance in the detection of HIV,HBV.However,given the high rate of intra and inter-genotypes recombination known for HIV and HBV,more robust techniques of detection such as polymerase chain reaction should be used to prevent post-transfusion contaminations.