Hepatitis B virus infection among pregnant women on antenatal visits: rapid tests or ELISA?

Background: Hepatitis B virus (HBV) infection is a global public health challenge with over 360 million people infected worldwide, and is one of the leading causes of death worldwide. The hepatitis B surface antigen (HBSAg) is the most important marker for HBV screening, and HBSAg rapid screening test methods are the most widely used compared with the enzyme-linked immunosorbent assay (ELISA) and nucleic acid testing methods. The objectives of this study are to evaluate the comparative efficacy of rapid test kits and ELISA for HBV screening among pregnant women on antenatal visits and to screen for other HBV serological markers among HBsAg positive patients. Methodology: This is a cross-sectional study of 172 pregnant women who were recruited consecutively on their first antenatal visit at the University College Hospital, Ibadan, Nigeria between November 2018 and February 2019. All participants were screened for HBsAg using both rapid immunochromatographic test (ICT) and ELISA techniques. HBsAg negative samples were further screened for anti-HBeAg/Ab, anti-HBcAg and anti-HBs by ELISA. Socio-demographic data of the participants were obtained using a semi-structured questionnaire, and data were analyzed using EPI INFO 7.2 statistical software. Results: The prevalence rate of HBsAg among pregnant women in this study was 10.5% (18/172). The sensitivity, specificity, accuracy, positive predictive value (PPV) and the negative predictive value (NPV) of the rapid ICT kit were 72.2%, 97.4%, 94.8%, 76.5% and 96.8% respectively. Level of education, previous history of sexually transmitted infections (STIs) and previous positive HBV results were significantly associated with HBsAg seropositivity. Majority of the pregnant women (66.9%) tested negative to all the serological markers. Conclusion: The low efficacy of rapid ICT kits compared to ELISA justifies the need to develop a safer antenatal screening strategy for HBV by combining the use of the less sensitive rapid screening techniques with the more sensitive ELISA method to limit vertical transmission of hepatitis B virus. Keywords: Hepatitis B virus; Rapid ICT kits; ELISA; pregnant women   French title: Infection par le virus de l'hépatite B chez les femmes enceintes en consultation prénatale: tests rapides ou ELISA? Contexte: L'infection par le virus de l'hépatite B (VHB) est un défi de santé publique mondial avec plus de 360 million de personnes infectées dans le monde et est l'une des principales causes de décès dans le monde. L'antigène de surface de l'hépatite B (HBSAg) est le marqueur le plus important pour le dépistage du VHB, et les méthodes de test de dépistage rapide HBSAg sont les plus largement utilisées par rapport aux méthodes de test immuno-enzymatique (ELISA) et d'acide nucléique. Les objectifs de cette étude sont d'évaluer l'efficacité comparative des kits de tests rapides et de l'ELISA pour le dépistage du VHB chez les femmes enceintes lors de consultations prénatales et de dépister d'autres marqueurs sérologiques du VHB chez les patients AgHBs positifs. Méthodologie: Il s'agit d'une étude transversale de 172 femmes enceintes qui ont été recrutées consécutivement lors de leur première visite prénatale à l'Hôpital Universitaire, Ibadan, Ibadan, Nigéria entre novembre 2018 et février 2019. Tous les participants ont été dépistés pour l'AgHBs en utilisant les deux tests immuno-chromatographiques rapides (TIC) et techniques ELISA. Les échantillons négatifs à l'AgHBs ont en outre été criblés pour l'anti-HBeAg/Ab, l'anti-HBcAg et l'anti-HBs par ELISA. Les données sociodémographiques des participants ont été obtenues à l'aide d'un questionnaire semi-structuré et les données ont été analysées à l'aide du logiciel statistique EPI INFO 7.2. Résultats: Le taux de prévalence de l'HBSAg chez les femmes enceintes dans cette étude était de 10,5% (18/172). La sensibilité, la spécificité, la précision, la valeur prédictive positive (VPP) et la valeur prédictive négative (VPN) du kit ICT rapide étaient respectivement de 72,2%, 97,4%, 94,8%, 76,5% et 96,8%. Le niveau d'éducation, les antécédents d'infections sexuellement transmissibles (IST) et les résultats positifs antérieurs pour le VHB étaient significativement associés à la séropositivité de l'AgHBs. La majorité des femmes enceintes (66,9%) ont été testées négatives pour tous les marqueurs sérologiques. Conclusion: La faible efficacité des kits TIC rapides par rapport à l'ELISA justifie la nécessité de développer une stratégie de dépistage prénatal plus sûre du VHB en combinant l'utilisation des techniques de dépistage rapide moins sensibles avec la méthode ELISA plus sensible pour limiter la transmission verticale du virus de l'hépatite B. Mots clés: virus de l'hépatite B; Kits TIC rapides; ELISA; femmes enceinte

Serum levels of inflammatory cytokines in helminth infested pregnant women and cord blood of their babies in relation to pregnancy outcome

Summary: Pregnancy places a very high demand on physical, physiological and immunological responses of females, especially when aggravated by parasitic infestation. There is strong evidence that maternal infestations with helminth have profound effects on immunity to helminths and other pathogens. This case-control study involved 245 pregnant women aged 18-40 years (>30 weeks of gestation) recruited from three secondary level hospitals in Ibadan, Nigeria. Morning stool samples collected from pregnant women were examine for intestinal helminths using formol-ether concentration method. A total of 38 participants comprising 17 Helminth Positive (HP) and 21 Helminth Negative (HN) pregnant women were purposely selected for the study. Sera from these women (38) and their babies’ cord (38) were analysed for immune factors [interleukins 6 and 8 (IL-6, IL-8), tumor necrosis factor-alpha (TNF-α) and immunoglobulin E (IgE)] were analyzed using ELISA. Anthropometric indices [weight and height in mothers and babies and Chest Circumference (CC) in babies] were measured using standard methods. Data were subjected to descriptive statistics and analysed using Student t-test and Pearson correlation at α0.05. Only Ascaris lumbricoides was found in the 17 (6.9%) infested pregnant women. The mean levels of IL-6 (57.8 ± 32.8 vs 52.8±39.6 pg/mL), IL-8 (24.3±3.5 vs 22.0±7.1 pg/mL) and IgE (333.3±96.6 vs 242.3±96.8 IU/mL) were similar in HP when compared with HN. In cord sera, IL-8 level was significantly higher in babies of HP (23.7±3.9 pg/mL) compared with babies of HN (20.1±5.9 pg/mL). The levels of IL-6, TNF-α and nutritional indices in HP had significant positive correlation with corresponding levels in babies of HP mothers. Only CC was significantly lowered in babies of HP compared with HN mothers. Other anthropometric indices were not significantly different. Therefore, this present study suggests that helminth infestation may lead to strong Th2 immune responses as is reflected by the cytokine levels of mothers and babies as well as anthropometric measurements of babies of infested mothers. The outcomes of this study provide basis to deworm pregnant women during pregnancy.Keywords: Helminths, Pregnancy, Cytokines, Cord-Blood, Pregnancy-Outcomes, Ig