The AgResults Nigeria Aflasafe TM Challenge Project: 2019 Annual Report

This report documents the key activities that were carried under the AgResults Aflasafe Pilot Project during the 2018/ 2019 maize-growing season on the verification process to trigger premium payments for successfully harvested and aggregated Aflasafe™-treated maize

Outbreak of Measles in vaccinated population in Southeastern Nigeria

Background: Outbreaks of respiratory disease, febrile illness and rash occurred in two adjoining rural communities of Imo State, Southeastern, Nigeria, at different times between 2006 and 2020. Laboratory investigation was carried out to determine the aetiological agent of the outbreak. Methodology: Oropharyngeal swabs were collected from 6 individuals showing symptoms of disease, within 3-4 days of appearance of rash. Venous blood samples were also collected from a total of 41 symptomatic persons, their contacts and individuals with resolved infections. Swabs were inoculated into Vero, HEp-2c, B95a and MDCK cell lines. Sera were analyzed using enzyme-linked immunosorbent assay (ELISA) for immunoglobulin G and M to rubella and measles viruses, while immunofluorescence assay was used to detect Lassa fever virus immunoglobulins. Descriptive data were analyzed using the Statistical Package for the Social Sciences (SPSS). Results: Four of the 6 (66.7%) swab samples showed viral activity or cytopathic effect characterized by clumping of cells in Vero cells while 2 (33.3%) in Hep-2c characterized by rounding up of cells. Thirty-nine (95.1%) sera were positive for measles IgG while 13 (31.7%) were positive for IgM. Thirty-six (87.8%) sera were positive for rubella IgG but none was positive for IgM. None of the sera was positive for Lassa fever virus IgG and IgM. Conclusion: Measles virus was responsible for the outbreak among previously vaccinated population in the communities, while Rubella and Lassa fever viruses were excluded as the etiological agents of the outbreak. Keywords: Epidemics; IgG and IgM; Cell lines; Vaccination; Measles virus   French title: Épidémie de rougeole dans la population vaccinée du sud-est du Nigéria Contexte: Des flambées de maladies respiratoires, de maladies fébriles et d'éruptions cutanées sont survenues dans deux communautés rurales voisines de l'État d'Imo, dans le sud-est du Nigéria, à des moments différents entre 2006 et 2020. Une enquête en laboratoire a été menée pour déterminer l'agent étiologique de l'épidémie. Méthodologie: Des écouvillons oropharyngés ont été prélevés sur 6 individus présentant des symptômes de maladie, dans les 3 à 4 jours suivant l'apparition de l'éruption cutanée. Des échantillons de sang veineux ont également été prélevés sur un total de 41 personnes symptomatiques, leurs contacts et des personnes souffrant d'infections résolues. Des écouvillons ont été inoculés dans des lignées cellulaires Vero, HEp-2c, B95a et MDCK. Les sérums ont été analysés en utilisant un test immuno-enzymatique (ELISA) pour les immunoglobulines G et M contre les virus de la rubéole et de la rougeole, tandis que le test d'immunofluorescence a été utilisé pour détecter les immunoglobulines du virus de la fièvre de Lassa. Les données descriptives ont été analysées à l'aide du progiciel statistique pour les sciences sociales (SPSS). Résultats: Quatre des 6 échantillons sur écouvillon (66,7%) ont montré une activité virale ou un effet cytopathique caractérisé par l'agglutination des cellules dans les cellules Vero, tandis que 2 (33,3%) dans Hep-2c étaient caractérisés par un arrondissement des cellules. Trente-neuf (95,1%) sérums étaient positifs pour les IgG contre la rougeole tandis que 13 (31,7%) étaient positifs pour les IgM. Trente-six (87,8%) sérums étaient positifs pour les IgG contre la rubéole, mais aucun n'était positif pour les IgM. Aucun des sérums n'était positif pour les IgG et IgM du virus de la fièvre de Lassa. Conclusion: Le virus de la rougeole était responsable de l'épidémie parmi la population précédemment vaccinée dans les communautés, tandis que les virus de la rubéole et de la fièvre de Lassa ont été exclus comme agents étiologiques de l'épidémie. Mots clés: épidémies; IgG et IgM; Lignées cellulaires; Vaccination; Virus de la rougeol

Factors affecting biofilm formation as seed transmission mechanism of cowpea bacteria blight induced by Xanthomonas axonopodis pv vignicola (Burkholder) Dye

Bacteria are carried in/on seeds by biofilm formation.  However relatively few studies have been focused on the factors affecting biofilm formation ability of Xanthomonas axonopodis pv. vignicola (Xav) as a mechanism of transmission. Knowing the factors that enabling plant-pathogenic bacteria to form biofilm as a means to move and establish on/in  the hosts provides the necessary basis to set up appropriate management approach. The study was conducted to determine factors affecting biofilm formation as mechanisms of seed transmission of Xanthomonas axonopodis pv. vignicola by growing bacterial  cells in  maize, millet, sorghum, Ife brown, Sampea7 extracts and extracts of Ife brown  + 0.5 g  nutrient glucose agar (NGA) in a 96 microlitre wells.  The seeds extract were prepared by soaking one hundred seeds each of Ife brown, Sampea7, millet, sorghum and maize in a 250 ml flask containing 100 ml SDW and  for 20 h. Bacterial suspension adjusted to ca. 4.5 x 107 cfu/ml was suspended in each of the extracts and the media and filled twelve wells each of the treatment. These were incubated for 72 h, 96 h and 120 h. afterwards, the wells were emptied and the wells were stained with 1 % crystal violet (CV) solution in 33 % (V/V) acetic acid for approximately 20 minutes. Excess CV was washed with SDW. The bound CV to the wells were solubilized with 200 µl of 33 % acetic acid or acetone – ethanol and quantified spectrophotometrically using Well Reader (GF 3000 microplate Reader –Bran scientific and Instrument Company England). Specific Biofilm formations (SBF) was calculated. The experiment was replicated two times and repeated 3 times. There was statistical difference between the biofilm formation induced by the different extracts and NGA.  All the seeds extract induces biofilm formation and the level of biofilm formation varies with time and the nutrient status of the media or medium

Precision and accuracy of stress measurement with a portable X-ray machine using an area detector

The use of portable X-ray stress analyzers, which utilize an area detector along with the newly adopted 'cosα' or full-ring fitting method, has recently attracted increasing interest. In laboratory conditions, these measurements are fast, convenient and precise because they employ a single-exposure technique that does not require sample rotation. In addition, the effects of grain size and orientation can be evaluated from the Debye ring recorded on the area detector prior to data analysis. The accuracy of the measured stress, however, has been questioned because in most cases just a single reflection is analyzed and the sample-to-detector distances are relatively short. This article presents a comprehensive analysis of the uncertainty associated with a state-of-the-art commercial portable X-ray device. Annealed ferrite reference powders were used to quantify the instrument precision, and the accuracy of the stress measurement was tested by in situ tensile loading on 1018 carbon steel and 6061 aluminium alloy bar samples. The results show that the precision and accuracy are sensitive to the instrument (or sample) tilt angle (ψ0) as well as to the selected hkl reflection of the sample. The instrument, sample and data analysis methods all affect the overall uncertainty, and each contribution is described for this specific portable X-ray system. Finally, on the basis of the conclusions reached, desirable measurement/analysis protocols for accurate stress assessments are also presented

Assessment of Water Quality Index of Borehole and Well Water in Wukari Town, Taraba State, Nigeria

Water samples collected from boreholes and hand dug wells located in two wards in Wukari town were assessedfor some physico-chemical parameters on collection and after one week of storage using standard analyticalmethods. Furthermore the quality indices were determined for the water samples on collection and after oneweek of storage. The parameters determined include temperature, turbidity, suspended solids, total dissolvedsolids, conductivity, pH, nitrate –nitrogen, phosphates, chlorides, alkalinity, COD and DO. The result showedthat some parameters like turbidity, conductivity and suspended solids exhibited a marked drop in valuefollowing their storage for one week in both borehole and hand dug well water samples. Mean values ofparameters like nitrate-nitrogen, phosphates and chlorides did not exhibit marked drop in concentration values inboth water sources. Turbidity and suspended solid values in the well water samples was more than that ofborehole waters however the mean conductivity values in borehole water is more than in well water. Water fromboth sources was found to exhibit hardness on collection and after one week of storage. The quality indices inborehole and well water on collection were found to be 26 and 136 respectively. After one week of storage thequality indices were determined and the values were found to be 15 and 89 respectively indicating improvementin the water quality after storage for one week. Borehole water in Wukari was found to possess better quality fordrinking than well water. The study provides baseline information on the quality of borehole and hand dug wellwaters in Wukari Town. In addition, the hardness of the water sources may be an indication of the presence ofunderlying minerals in the ground.Keywords: Borehole, hand dug well, storage,water quality inde

Perception of Nigerian tobacco control law by consumers of tobacco products in Ibadan, Oyo State, Nigeria

Tobacco use in any form has been identified for decades as a source of diseases and avoidable deaths all over the world. Cognizant of this fact, the Federal Government of Nigeria has, over the years, put in place successive laws to control the consumption of tobacco products. This study surveyed the awareness of tobacco control law by consumers of tobacco products; reasons for tobacco consumption;  knowledge of harmful effects of tobacco consumption on smokers; adverse effects on non-voluntary smokers; willingness to quit smoking; and reasons for unwillingness to quit. Neutralization and Rational Action theories were used as the basis for the study while survey  research design was adopted. Multi-stage sampling technique was adopted to select the eight wards in the two communities while simple random sampling technique was used to select four hundred and ninety-four participants for the study. The respondents completed standardised questionnaire which measured the constructs under study. Descriptive statistics were used to analyse the data collected. Among other findings, 103 (15%) of the respondents are aware that cigarette smoking can cause cancer while 85 (13%) are aware that nonvoluntary smokers could develop heart diseases. A good number of the respondents 193 (41%) opined that tobacco warning messages are exaggerated; 209 (45%) – that the messages are distorted; 212 (45%) that the messages are boring. From the totality of the opinions expressed by respondents on the various issues covered by this study, it is obvious that many consumers of tobacco products are not aware of the measures put in place to curtail the consumption of tobacco products. To achieve the goal of safeguarding public health through tobacco smoking control, the paper recommends effective enforcement by the regulatory agencies and intensive awareness creation to educate members of the public on the health risks associated with consumption and exposure to tobacco products

Monitoring Aspergillus flavus genotypes in a multi-genotype aflatoxin biocontrol product with quantitative pyrosequencing

Open Access Journal; Published online: 15 Nov 2019Aflatoxins pose significant food security and public health risks, decrease productivity and profitability of animal industries, and hamper trade. To minimize aflatoxin contamination in several crops, a biocontrol technology based on atoxigenic strains of Aspergillus flavus is commercially used in the United States and some African countries. Significant efforts are underway to popularize the use of biocontrol in Africa by various means including incentives. The purpose of this study was to develop quantitative pyrosequencing assays for rapid, simultaneous quantification of proportions of four A. flavus biocontrol genotypes within complex populations of A. flavus associated with maize crops in Nigeria to facilitate payment of farmer incentives for Aflasafe (a biocontrol product) use. Protocols were developed to confirm use of Aflasafe by small scale farmers in Nigeria. Nested PCR amplifications followed by sequence by synthesis pyrosequencing assays were required to quantify frequencies of the active ingredients and, in so doing, confirm successful use of biocontrol by participating farmers. The entire verification process could be completed in 3–4 days proving a savings over other monitoring methods in both time and costs and providing data in a time frame that could work with the commercial agriculture scheme. Quantitative pyrosequencing assays represent a reliable tool for rapid detection, quantification, and monitoring of multiple A. flavus genotypes within complex fungal communities, satisfying the requirements of the regulatory community and crop end-users that wish to determine which purchased crops were treated with the biocontrol product. Techniques developed in the current study can be modified for monitoring other crop-associated fungi

Pseudomonas syringae Differentiates into Phenotypically Distinct Subpopulations During Colonization of a Plant Host

© 2016 Society for Applied Microbiology and John Wiley & Sons Ltd Bacterial microcolonies with heterogeneous sizes are formed during colonization of Phaseolus vulgaris by Pseudomonas syringae. Heterogeneous expression of structural and regulatory components of the P. syringae type III secretion system (T3SS), essential for colonization of the host apoplast and disease development, is likewise detected within the plant apoplast. T3SS expression is bistable in the homogeneous environment of nutrient-limited T3SS-inducing medium, suggesting that subpopulation formation is not a response to different environmental cues. T3SS bistability is reversible, indicating a non-genetic origin, and the T3SSHIGH and T3SSLOW subpopulations show differences in virulence. T3SS bistability requires the transcriptional activator HrpL, the double negative regulatory loop established by HrpV and HrpG, and may be enhanced through a positive feedback loop involving HrpA, the main component of the T3SS pilus. To our knowledge, this is the first example of phenotypic heterogeneity in the expression of virulence determinants during colonization of a non-mammalian host

The Plant Pathogen Pseudomonas syringae pv. tomato Is Genetically Monomorphic and under Strong Selection to Evade Tomato Immunity

Recently, genome sequencing of many isolates of genetically monomorphic bacterial human pathogens has given new insights into pathogen microevolution and phylogeography. Here, we report a genome-based micro-evolutionary study of a bacterial plant pathogen, Pseudomonas syringae pv. tomato. Only 267 mutations were identified between five sequenced isolates in 3,543,009 nt of analyzed genome sequence, which suggests a recent evolutionary origin of this pathogen. Further analysis with genome-derived markers of 89 world-wide isolates showed that several genotypes exist in North America and in Europe indicating frequent pathogen movement between these world regions. Genome-derived markers and molecular analyses of key pathogen loci important for virulence and motility both suggest ongoing adaptation to the tomato host. A mutational hotspot was found in the type III-secreted effector gene hopM1. These mutations abolish the cell death triggering activity of the full-length protein indicating strong selection for loss of function of this effector, which was previously considered a virulence factor. Two non-synonymous mutations in the flagellin-encoding gene fliC allowed identifying a new microbe associated molecular pattern (MAMP) in a region distinct from the known MAMP flg22. Interestingly, the ancestral allele of this MAMP induces a stronger tomato immune response than the derived alleles. The ancestral allele has largely disappeared from today's Pto populations suggesting that flagellin-triggered immunity limits pathogen fitness even in highly virulent pathogens. An additional non-synonymous mutation was identified in flg22 in South American isolates. Therefore, MAMPs are more variable than expected differing even between otherwise almost identical isolates of the same pathogen strain