In vitro assessment of the potency of some Newcastle disease vaccine brands in Ibadan, Nigeria

Background: Newcastle disease (ND) is a very common and economically important disease of poultry. There is no drug for treatment of the disease during an outbreak in poultry flocks, and prevention by vaccination is one of the recommended control measures. However, post vaccination outbreaks have been observed on many occasions in chicken flocks and one of the causes has been attributed to possible failure of vaccine to confer immunity. This study was designed to evaluate the potency of ND vaccines available in Ibadan, Nigeria. Methodology: Haemagglutination (HA) technique and elution phenomenon were employed to evaluate the potency of ND vaccines randomly selected in Ibadan. A total of 45 vaccines comprising 9 brands and 5 different strains were selected for potency test. The vaccine brands included ‘Vireo 116’ (n=10), ‘ABIC’ (n=5), ‘Biovac’(n=9), ‘Nobilis’(n=3), ‘NVRI’(n=12), ‘R2B’ (n=2), ‘BAL-ND’ (n=2), ‘Forte dodge’(n=1) and ‘Jovac’ (n=1), while the vaccine strains in the brands included Lasota, B1, Clone, Komarov, Hitcher, and an unknown strain. Results: Thirty-five of the 45 (77.8%) ND vaccines tested had more than 4 HA titer (>64) and were therefore regarded as potent. All the 15 (100%) ND Lasota vaccine strain, 7 out of 10 (70%) ND Komarov strain, 4 out of 5 (80%) ND clone and 5 out of 8 (62.5%) ND B1 strains were potent. None of the ND brand ‘R2B’ vaccine as well as Hitchner strain from ‘Nobilis’ brand was potent, but all 5, 2, 1 and 1 vaccines tested from brands ‘ABIC’, ‘BAL-ND’, ‘Fort dodge’ and ‘Jovac’ respectively were potent. Similarly, 9 of 10, 6 of 9, 2 of 3 and 9 of 12 vaccine strains tested from brands ‘Vireo 116’, ‘Biovac’, ‘Nobilis’ and ‘NVRI’ were respectively potent Conclusion: The occurrence of ND vaccines that are not potent in this study may be contributing to post vaccination failure. It is advisable to subject vaccines to potency test before use. Key words: in vitro, assessment, potency, Newcastle disease, vaccine brands, vaccine strains   French Title; Évaluation in vitro de la puissance de certaines marques de vaccins contre la maladie de Newcastle à Ibadan, Nigéria Contexte: La maladie de Newcastle (ND) est une maladie très courante et économiquement importante des volailles. Il n'existe aucun médicament pour le traitement de la maladie lors d'une épidémie dans des troupeaux de volailles, et la prévention par vaccination est l'une des mesures de contrôle recommandées. Cependant, des flambées post-vaccination ont été observées à de nombreuses reprises dans des troupeaux de poulets et l'une des causes a été attribuée à un éventuel échec du vaccin à conférer l'immunité. Cette étude a été conçue pour évaluer la puissance des vaccins contre la MN disponibles à Ibadan, au Nigéria. Méthodologie: La technique d'hémagglutination (HA) et le phénomène d'élution ont été utilisés pour évaluer la puissance des vaccins contre la MN sélectionnés au hasard à Ibadan. Un total de 45 vaccins comprenant 9 marques et 5 souches différentes ont été sélectionnés pour le test d'activité. Les marques de vaccins comprenaient 'Vireo 116' (n=10), 'ABIC' (n=5), 'Biovac' (n=9), 'Nobilis' (n=3), 'NVRI' (n=12), 'R2B' (n=2), 'BAL-ND' (n=2), 'Forte dodge' (n=1) et 'Jovac' (n=1), tandis que les souches vaccinales des marques comprenaient Lasota, B1, Clone, Komarov, Hitcher et une souche inconnue. Résultats: Trente-cinq des 45 vaccins contre la MN testés (77,8%) avaient plus de 4 titres en HA (>64) et étaient donc considérés comme puissants. Toutes les 15 (100%) souches de vaccin ND Lasota, 7 souches sur 10 (70%) ND Komarov, 4 sur 5 (80%) clones ND et 5 sur 8 (62,5%) souches ND B1 étaient puissantes. Aucun des vaccins ’R2B’ de marque ND ni la souche Hitchner de la marque ’Nobilis’ n'étaient puissants, mais tous les vaccins 5, 2, 1 et 1 testés des marques ‘ABIC’, ‘BAL-ND’, ‘Fort dodge’ et ‘Jovac’ respectivement était puissant. De même, 9 des 10, 6 des 9, 2 des 3 et 9 des 12 souches vaccinales testées des marques ’Vireo 116’, ‘Biovac’, ‘Nobilis’ et ‘NVRI’ étaient respectivement puissantes Conclusion: La présence de vaccins contre la MN qui ne sont pas puissants dans cette étude peut contribuer à l'échec post-vaccinal. Il est conseillé de soumettre les vaccins à un test de puissance avant utilisation. Mots-clés: in vitro, évaluation, puissance, maladie de Newcastle, marques de vaccin, souches vaccinale

Geo-spatial distribution of Brucella melitensis infection in selected local government areas of Katsina and Sokoto States, Nigeria

Brucellosis due to Brucella melitensis infects mostly small ruminants and has been reported to be the most invasive and pathogenic species for humans. A cross-sectional sero-geospatial study was conducted in 4 and 3 Local Government Areas (LGAs) of Katsina and Sokoto States, Nigeria respectively. Sera were analysed using c-ELISA while A Global Positioning System (GPS) receiver was used to take geographic coordinates of all sampling points. Data were analysed with SPSS version 20. Chi-square test was used to measure associations among categorical variables. ArcGIS 10.3 was used to map the geospatial pattern of distribution of B. melitensis. Three-dimensional analysis was also performed using the Inverse Distance Weighted (IDW) interpolation to determine the distribution pattern of B. melitensis in unsampled LGAs. Six (10.52%), 11 (20.0%), 11(2.0%) and 23 (23.0%) sera were positive from Bakori (n=57), Baure (n=56), Daura (n=55) and Funtua (n=101) LGAs of Katsina State respectively while 4 (12.5%), 1 (5.6%), 13 (14.8%) were positive from Illela (n=22), Tambuwal (n=19) and Yabo (n=90) LGAs respectively in Sokoto State were positive for B. melitensis antibodies. All the variables tested were not statistically significant (p ≤ 0.05). The geospatial maps for both States were produced to show the prevalence of B. melitensis using c-ELISA throughout the LGAs sampled and extrapolation was done for other unsampled LGAs. Small ruminants in the study areas harboured antibodies to B. melitensis. The maps may serve as an excellent tool for active surveillance and control strategies for livestock diseases like brucellosis in the study area.Keywords: Brucella melitensis, Small Ruminants, Nigeria, c-ELISA, GI

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Application of Nanofiltration for Reclamation and Reuse of Wastewater and Spent Geothermal Fluid

After the extraction of energy from the geothermal fluid, the consumed geothermal water can be considered as a potential water resource for agricultural and industrial purposes. The used geothermal water can also be used as a source of drinking water, which could reduce the pressure on the current clean water resources. On the other hand, geothermal fluids brought to the surface need to be treated in the most economical way before discharge into the surface environment or aquifer. Several processes have shown promising results for the treatment of geothermal water. Membrane processes such as nanofiltration (NF) and reverse osmosis (RO) can be considered as a technology for obtaining good quality irrigation water from geothermal water. This chapter summarizes the application of NF for the recovery and reuse of wastewater and spent geothermal water. © 2024 selection and editorial matter, Abdul Wahab Mohammad, Teow Yeit Haan and Nidal Hidal; individual chapters, the contributors