Species-specific field testing of Entamoeba spp. in an area of high endemicity

Entamoeba histolytica has been separated in recent years into 2 morphologically identical species: the apathogenic E. dispar and the pathogenic E. histolytica, only the latter being pathogenic. Although various laboratory techniques allow discrimination between the 2 species there is a lack of field data about the suitability of available diagnostic tests for use in epidemiological studies and few epidemiological studies using species-specific diagnosis have been performed at community level in endemic areas, especially in sub-Saharan Africa. We conducted a repeated cross-sectional study of 967 schoolchildren in central Côte d'Ivoire to compare and evaluate light microscopy, 2 different antigen detection assays, and one polymerase chain reaction (PCR) assay. Microscopy and a non-specific antigen capture Entamoeba enzyme-linked immunosorbent assay (ELISA) were used for the primary screening of all children (time t0). The prevalence of the E. histolytica/E. dispar species complex at t0 was 18 · 8% by single microscopical examination and 31 · 4% using the non-specific ELISA. Approximately 2 months after the initial screening, fresh stool specimens were collected on 2 consecutive days (t1, and t2) from (i) all the children who were positive by microscopy at t0 (n = 182) and (ii) 155 randomly selected children who were negative at the primary screening. These samples were tested with a second antigen detection ELISA specific for E. histolytica (n = 238) and with a species-specific PCR assay (n = 193). The second and third examinations (t1, and t2) revealed an additional 43 infections with the species complex E. histolytica/E. dispar, so that the cumulative microscopical prevalence for t1 and t2 was 27 · 7%. The overall prevalence of E. histolytica by species-specific ELISA antigen detection was low (0 · 83%), while the prevalence of E. dispar was 15%. When analysing only microscopically positive samples by PCR (n = 129), the ratio E. histolytica: E. dispar was very low (1:46), suggesting that the vast majority of Entamoeba infections in this area were apathogenic. Both species-specific tests performed well but the ELISA was easier to use for large-scale field screenin

Emergence of new SARS-CoV-2 Variant of Concern Omicron (B.1.1.529) - highlights Africa's research capabilities, but exposes major knowledge gaps, inequities of vaccine distribution, inadequacies in global COVID-19 response and control efforts

Nearly two years since the start of the SARS-CoV-2 pandemic, which has caused over 5 million deaths, the world continues to be on high COVID-19 alert. The World Health Organization (WHO), in collaboration with national authorities, public health institutions and scientists have been closely monitoring and assessing the evolution of SARS-CoV-2 since January 2020 (WHO 2021a; WHO 2021b). The emergence of specific SARS-CoV-2 variants were characterised as Variant of Interest (VOI) and Variant of Concern (VOC), to prioritise global monitoring and research, and to inform the ongoing global response to the COVID-19 pandemic. The WHO and its international sequencing networks continuously monitor SARS-CoV-2 mutations and inform countries about any changes that may be needed to respond to the variant, and prevent its spread where feasible. Multiple variants of the virus have emerged and become dominant in many countries since January 2021, with the Alpha, Beta, Gamma and Delta variants being the most prominent to date. (Table 1)

Peri-urban livestock production and Development in sub-Saharan Africa: A review of the constraints and opportunities

The demand for livestock products in sub-Saharan Africa is increasing steadily. This demand is driven by human population, rural-urban demographic shifts and income growth. In sub-Saharan Africa, population is expected to increase from the present 500 million to nearly 1300 million in 2025. Urbanization is also increasing rapidly. Currently, only 14.5 million people are urban dwellers, but by 2025, more than 700 million people will be living in sub-Saharan cities and towns. Between 1990 and 2025, the proportion of population living in cities, is projected to increase from 27 to 54 percent. Urbanization will force the commercialization of agriculture and increase the demand for foods of animals origin (Winrock, 1992). If livestock production does not increase, it is projected that sub-Saharan Africa will face massive deficits in meat and milk supplies by 2025. Therefore policy makers constantly face the questions of what strategies to formulate that will foster the expansion of food products to feed the growing populations. Peri-urban livestock production systems characterized by intensive commercial systems developing around cities are emerging as alternatives or mechanisms by which urban food security can be enhanced. The purpose of this paper is to review the constraints to, and opportunities for peri-urban livestock Development and discuss the role of international livestock research in contributing to sustainable food production. The paper first reviews the intensification process to highlight the stage at which peri-urban livestock systems enters the animal Development strategy. The next section gives an overview of peri-urban livestock Development systems in selected countries in SSA focusing on small ruminants and dairy. In the third section, the constraints to peri-urban livestock Development are reviewed. In the fourth section, the potential for Development of peri-urban livestock systems is addressed. The role of international lviestock research is highlighted in the fifth section

Risk factors for schistosomiasis in an urban area in northern Cote d'Ivoire

Background Schistosomiasis is a water-based disease transmitted by trematodes belonging to the genus Schistosoma. The aim of this study was to assess the relationship between the prevalence of schistosomiasis and access to water, sanitation and hygiene (WASH) and environmental and socioeconomic factors in the city of Korhogo, northern Côte d'Ivoire. Methods A cross-sectional study including 728 randomly selected households was conducted in Korhogo in March 2015. The heads of the households were interviewed about access to WASH and environmental and socioeconomic factors. All children abed between 5 and 15 years living in the households were selected to provide stool and urine samples for parasitological diagnosis of Schistosoma mansoni and Schistosoma haematobium infection. The relationship between infection with S. mansoni and potential risk factors was analysed by a mixed logistic regression model with ‘household’ as a random factor. Likelihood ratio tests were used to identify factors that were significantly associated with a Schistosoma spp. infection. Results The overall prevalence of schistosomiasis among school-aged children in Korhogo was 1.9% (45/2341) composed of 0.3% (3/1248) S. haematobium and 3.5% (42/1202) S. mansoni. Due to the low prevalence of S. haematobium infection, risk factor analysis was limited to S. mansoni. Boys were 7.8 times more likely to be infected with S. mansoni than girls. Children between 10 and 15 years of age were 3.8 times more likely to be infected than their younger counterparts aged 5-10 years. Moreover, living in a house further away from a water access point (odds ratio [OR] = 0.29, 95% confidence interval [CI]: 0.13–0.70) and abstaining from swimming in open freshwater bodies (OR = 0.16, 95% CI: 0.04–0.56) were significantly associated with decreased odds of S. mansoni infection. The socioeconomic status did not appear to influence the prevalence of S. mansoni. Conclusions A strategy to reduce the incidence of schistosomiasis should focus on health education to change the behaviour of populations at risk and encourage communities to improve sanitation and infrastructure in order to reduce contact with surface water

Poids vif et paramètres de la courbe de croissance des poulets de race locale (Gallus domesticus) en Côte d’Ivoire

Une étude a été menée sur l'aptitude de croissance des poulets dans un système de production semiintensif, en vue de valoriser la poule locale de Côte d'Ivoire. Le site d'expérimentation a été celui de la station de recherche La Mé, Centre National de Recherche Agronomique (CNRA), en zone forestière humide de Côte d'Ivoire. La croissance pondérale des poulets traditionnels de génotypes Savane et de Forêt a été comparée aux poulets de souche Label Rouge (T55 x SA51) importés de France. Les poulets Label ont présenté une croissance pondérale plus élevée que ceux de génotype local (Savane et Forêt). Les coqs de toutes les souches de poulets ont présenté les meilleurs poids, par rapport aux poules. Le dimorphisme sexuel a été observé dès l'âge de 4 semaines. Par ailleurs, contrairement aux poules, les poids moyens des coqs Savane ont été supérieurs à ceux des coqs Forêt ; ceux-ci ont été supérieur à 1500 g pour les poulets âgés de 20 semaines. Les courbes de croissance des poulets mâles Label ont présenté un point d'inflexion à un âge plus précoce (53 j) que les autres (73 j pour Savane et 77 j pour Forêt). Les vitesses de maturation ont été plus faibles chez les poulets de forêt (0,0189 g j-1 pour les coqs et 0,0199 g j-1 pour les poules) et plus élevées pour les poules Label (0,0274, g j-1 pour les coqs et 0,0224 g j-1 pour les poules). Le poids asymptotique a été de 3 076, 2 219 et 2 160 g, respectivement, chez les coqs Label, Forêt et Savane.A study was undertaken on the growth characteristics of poultry in a semi-intensive production system, in order to contribute to the enhancement of local poultry production in Côte d'Ivoire. It was conducted at the research station of La Mé, National Center for Agricultural Research (CNRA), in wet forest belt of Côte d'Ivoire. The body weight of traditional Savanna and Forest genotypes was compared with chickens of Label Rouge stock (T55 x SA51) imported from France. Label chickens showed a higher weight gain than chickens of local genotype (Savanna and Forest). The roosters of all chicken strains showed better weight gain, as compared to females. Sexual dimorphism was clearly apparent at 4 weeks of age. Moreover, unlike hens, the average weights of the Savanna roosters were higher than those of the Forest; these weights reached more than 1500 g at 20 weeks of age. Label male chickens curves presented an earlier age at inflexion (53 d) than others (73 d, for Savanna and 77 d for Forest). The Maturation rate were lowest in Forest chickens of 0.0189 g j-1 for roosters and 0.0199 g j-1, for hens and highest, for Label chickens (0.0274 g j-1, for roosters and 0.0224 g j-1, for hens). The asymptotic weights were 3 076, 2 219 and 2 160 g, in Label, Forest and Savanna roosters, respectively. Keywords: Genotype, traditional chicken, growth parameters, Côte d'Ivoir

Évaluation et modélisation de la production de lait des vaches Girolando, Borgou, Lagunaire et croisées Azawak × Lagunaire, élevées dans le système semiamélioré au Bénin

Objectif : Le Bénin regorge d’une diversité génétique de races bovines dont les rendements de lait sont peu connus. Le but de l'étude est d'évaluer et de modéliser la production de lait des vaches en système semi-amélioréMéthodologie et résultats : A cet effet, 75 vaches Girolando de la Ferme de Kpinnou, 30 vaches Borgou, 20 vaches Lagunaire et 20 vaches métissées Azawak x Lagunaire de la Ferme de Samiondji, ont été utilisées pour la collecte des données. Les vaches en lactation ont été identifiées avant la collecte de lait, qui a été faite une fois par semaine pour une période de lactation de 11 mois. Des mesures ponctuelles de quantités totales réelles de lait par jour ont également été prises. Il en résulte que sur les 11 mois de lactation, la meilleure (p<0,001) quantité de lait a été obtenue chez la vache Girolando (4,77 l/j), suivie par la vache Borgou (0,83 l/j), la vache métissée Azawak x Lagunaire (0.69 l/j) et celle de race Lagunaire (0,36 l/j). Une tendance similaire a été observée pour les quantités totales de lait pendant les 11 mois de lactation chez les vaches Girolando, Borgou, Azawak x Lagunaire et Lagunaire avec des productions totales respectives de 1469,58 litres, 256,41 litres, 213,43 litres et 110,67 litres. Pour estimer la quantité totale de lait produit par les vaches, les régressions qui ont été développées sont logarithmiques chez les bovins Girolando (R²=0,89) et les Borgou (R²=0,90). Les équations obtenues chez les bovins Lagunaire (R²=0,89) et les croisées Azawak x Lagunaire (R²=0,91) sont respectivement de types exponentiel et  olynômiale. Pour la période de lactation, la production moyenne de lait estimée (6,87 litres) de la vache Girolando par jour était la plus élevée et la vache Lagunaire a donné une production journalière moyenne estimée la plus faible (0,42 litre). Les Girolando sont suivis par les vaches Borgou qui ont produit quotidiennement en moyenne une quantité de lait estimée à 1 litre, suivies des croisées Azawak x Lagunaire (0,81 litre). Les mêmes tendances ont été observées pour la quantité totale estimée de lait au cours des 11 mois de lactation, pour les 4 races de l'étude.Conclusion et application : Ces résultats représentent une base scientifique pour la mise en place d'un programme d’amélioration génétique.Mots-clés : Lait, modélisation, bétail, croisés, Bénin