Plant Parasitic Nematodes Associated With Coffee in Kenya and Factors Influencing their Occurrence, Abundance and Diversity

Frequent detection of galls on coffee roots has raised concerns of nematodes in coffee production systems in Kenya. This study aimed at determining the occurrence of nematodes associated with coffee in Kenya and the role of crop management, cultivars, soil properties and agro ecological zones on the abundance and frequency of nematodes. A survey was conducted in the prime coffee growing areas in 10 counties namely; Machakos, Makueni, Kiambu, Embu, Kirinyanga, Nyeri, Meru, Kisii, Nandi and Trans-Nzoia. Nematodes were extracted using a combination of centrifugal floatation and Modified Baermann techniques and identified to genera level.  Nutrient analysis was carried out using the Double Mehlich method. Results showed that nematodes belonging to 30 genera were recovered from coffee agro-ecosystems. Plant parasitic nematodes were the most prevalent with 64% frequency (19 genera) of occurrence followed by bacterial feeders at 24%. The genus Tylenchulus, Meloidogyne and Pratylenchus were the most dominant across all the coffee growing areas. Coffee farms in the coffee-tea zones (Upper Midland 1) harbored the highest numbers of plant parasitic nematodes, followed by Upper Midland 2 and least in the marginal coffee growing zones (Upper Midland 3). Well managed farms had less plant parasitic nematodes compared to neglected farms. K and P significantly contributed to the variation in the nematode community composition. This study demonstrated the prevalence of plant parasitic nematodes, factors that influence their abundance and distribution and justifies need for further management of nematodes in coffee production. Key words: Abundance, agro-ecologial zones, diversity, nematode genera, nutrient

Reaction of Selected Coffee Germplasm to Root-Knot Nematodes in Kenya

Coffee is one of the most important cash crops in Kenya and a leading export earner. Nematodes are among the most important biotic constraint in coffee production in Kenya and crop improvement work has mainly been breeding for resistance to diseases such as coffee berry disease and coffee leaf rust. However resistance has been used successfully in other coffee producing countries and it is one of the most economical and practical nematode management strategies. A greenhouse study was conducted to test the response of local and exotic coffee germplasm to root knot nematodes (RKNs). Ten (10) cultivars provided by Coffee Research Foundation (CRF) were tested for resistance to Meloidogyne incognita under greenhouse conditions (25±2oC). Nematodes were extracted from the roots using Modified Baermann Technique and enumerated using Cobbs slide. After 90 days of plant growth, the disease severity was evaluated and the experiment repeated twice. Galling indices (GI), egg mass indices (EMI) and nematode populations recovered from soil samples indicated a range of responses from resistant to highly susceptible.  Three breeder’s lines including Robusta tree 1, Robusta tree 2 and Robusta tree 3 were rated resistant with galling indices of 1.2-3.0. This study has demonstrated the potential of host resistance as a strategy in the management of nematodes in coffee for increased productivity. Field evaluation needs to be conducted to confirm these findings. The identified resistance sources can be utilized to deploy resistance genes to improve existing varieties that have high commercial value but lack resistance to nematodes.   Key words: Resistance, susceptible, galling indices, nematode population, cultivar

Antimalarial activities and toxicity levels of selected medicinal plants used in Kenya

Background: Resistance development to antimalarial drugs necessitates the look at traditional medicinal plants as sources of novel compounds that could have the otential to be developed into new antimalarial therapies. Four medicinal plants used in Kenya to treat malaria were investigated. Objective: To determine the in vitro and in vivo antimalarial activity and safety of four medicinal plants used in Kenya to treat malaria. Materials and Methods: Ximenia americana, Sericocomopsis hilderbrandtii, Pentas lanceolata and Fuerstia africana were collected from their habitat, dried, and extracted with methanol and aqueous solvents. In vitro antiplasmodial activity carried out using Plasmodium falciparum, In vivo antimalarial activity using Plasmodium berghei ANKA strain in Swiss albino mice. Cytotoxicity was carried out using MTT assay on VeroE99 cell lines, acute toxicity was investigated in Swiss albino mice. Results: All extracts had good in vitro activity against D6 strain of Plasmodium falciparum with IC50<20µg/ml.  Aerial parts of Fuerstia africana methanol extract had the highest in vitro activity.  Seven extracts showed good in vivo activity with chemosuppresion >30% while three demonstrated low activity. Fuerstia africana was moderately cytotoxic. Except for Ximenia americana water extract, all the extracts were safe with LD50 > 5000mg/Kg. Conclusion: Results of this study support medicinal use of these plants and indicate that useful compounds can be isolated for further exploitation, formulation and use. Keywords: Medicinal plants, antiplasmodial activity, cytotoxicity, acute toxicit

Antimalarial potential and phytochemical composition of fractions of Lippia kituiensis Vatke (Verbenaceae) growing in Northern Tanzania

This research article published by Journal of Medicinal Plants Research, 2020Despite past decades of steady advances in the fight against Malaria, statistics show that the disease is still a threat to human health. Previous successes in the development of antimalarial drugs from medicinal plants have fuelled research in this area. However, antimalarial studies on fractionated extracts from such plants have progressed slowly. This study reports the antimalarial potential of fractions from Lippia kituiensis Vatke, for the first time. Column chromatography was used during fractionation. Antiplasmodial assay against chloroquine-sensitive (D6) and resistant (W2) plasmodium strains were done using hypoxanthine incorporation assay. MTT assay was used to assess the cytotoxicity of fractions against the Vero cell line. Fractions obtained exhibited varied inhibitory concentrations (IC50); with the most efficacious being, Lk-5 (19.45 ± 6.20 μg/ml), Lk-3 (30.43 ± 0.68 μg/ml), Lk-4 (30.82 ± 18.01 μg/ml), and Lk-6 (36.53 ± 14.42 μg/ml) against D6. Generally, lower activity against W2 was obtained with the most active being LK-4 (24.18±2.50 μg/ml), and Lk-5 (24.42±5.95 μg/ml), while chloroquine (positive control) exerted IC50 of 77.86±4.09 ng/ml (W2) and 15.71±6.49 ng/ml (D6). LK-4 was the most cytotoxic showing cytotoxic concentration (CC50), 46.26 μg/ml. When tested in mice, fractions suppressed Plasmodium berghei significantly compared to the negative control with Lk-3 being most efficacious (80.01±1). Due to substantive efficacy, GC-MS done on Lk-3 revealed 8 compounds where three have previously been ascribed to antimalarial activity and other pharmacological effects. This study adds to present knowledge of antimalarial efficacy of L. kituiensis and provides the basis for further work to be done on the isolation of compounds from its extracts

Uptake of home-based voluntary HIV testing in sub-Saharan Africa: a systematic review and meta-analysis

Improving access to HIV testing is a key priority in scaling up HIV treatment and prevention services. Home-based voluntary counselling and testing (HBT) as an approach to delivering wide-scale HIV testing is explored here

Technological Revolution, Sustainability and Development in Africa: Overview, Emerging Issues and Challenges

The paper examines the silent technological revolution in sub‐Saharan Africa focusing on emerging issues and challenges. In view of the centrality of technology diffusion in fostering local innovations and economic development in developing countries, it is surprising that our understanding of the challenges and opportunities in scaling‐up technologies remains limited. This paper capitalises on the ongoing silent technological revolution in sub‐Saharan Africa to present an overview of how new technologies have been adopted and utilised to achieve sustainability. The study identified a host of factors such as weak regulatory enforcement systems, lack of financial credit availability, and limited banking services, which have created conditions for technological innovations such as mobile phone‐based banking, mPedigree, “cardiopad,” and M‐PEPEA to emerge. The public policy implications and directions for future research are identified and examined

Relationships between Parental Education and Overweight with Childhood Overweight and Physical Activity in 9-11 Year Old Children: Results from a 12-Country Study

Background: Globally, the high prevalence of overweight and low levels of physical activity among children has serious implications for morbidity and premature mortality in adulthood. Various parental factors are associated with childhood overweight and physical activity. The objective of this paper was to investigate relationships between parental education or overweight, and (i) child overweight, (ii) child physical activity, and (iii) explore household coexistence of overweight, in a large international sample. Methods: Data were collected from 4752 children (9-11 years) as part of the International Study of Childhood Obesity, Lifestyle and the Environment in 12 countries around the world. Physical activity of participating children was assessed by accelerometry, and body weight directly measured. Questionnaires were used to collect parents' education level, weight, and height. Results: Maternal and paternal overweight were positively associated with child overweight. Higher household coexistence of parent-child overweight was observed among overweight children compared to the total sample. There was a positive relationship between maternal education and child overweight in Colombia 1.90 (1.23-2.94) [odds ratio (confidence interval)] and Kenya 4.80 (2.21-10.43), and a negative relationship between paternal education and child overweight in Brazil 0.55 (0.33-0.92) and the USA 0.54 (0.33-0.88). Maternal education was negatively associated with children meeting physical activity guidelines in Colombia 0.53 (0.33-0.85), Kenya 0.35 (0.19-0.63), and Portugal 0.54 (0.31-0.96). Conclusions: Results are aligned with previous studies showing positive associations between parental and child overweight in all countries, and positive relationships between parental education and child overweight or negative associations between parental education and child physical activity in lower economic status countries. Relationships between maternal and paternal education and child weight status and physical activity appear to be related to the developmental stage of different countries. Given these varied relationships, it is crucial to further explore familial factors when investigating child overweight and physical activity

Effects of co-habitation between Anopheles gambiae s.s. and Culex quinquefasciatus aquatic stages on life history traits

<p>Abstract</p> <p>Background</p> <p>The effective measures for the control of malaria and filariasis vectors can be achieved by targeting immature stages of anopheline and culicine mosquitoes in productive habitat. To design this strategy, the mechanisms (like biotic interactions with conspecifc and heterospecific larvae) regulating mosquito aquatic stages survivorship, development time and the size of emerging adults should be understood. This study explored the effect of co-habitation between <it>An. gambiae </it>s.s. and <it>Cx. quinquefasciatus </it>on different life history traits of both species under different densities and constant food supply in the habitats of the same size under semi-natural conditions.</p> <p>Methods</p> <p>Experiments were set up with three combinations; <it>Cx. quinquefasciatus </it>alone (single species treatment), <it>An. gambiae </it>s.s. alone (single species treatment); and <it>An. gambiae </it>s.s. with <it>Cx. quiquefasciatus </it>(co-habitation treatment) in different densities in semi field situation.</p> <p>Results</p> <p>The effect of co-habitation of <it>An. gambiae </it>s.s. and <it>Cx. quinquefasciatus </it>was found to principally affect three parameters. The wing-lengths (a proxy measure of body size) of <it>An. gambiae </it>s.s. in co-habitation treatments were significantly shorter in both females and males than in <it>An. gambiae </it>s.s single species treatments. In <it>Cx. quinquefasciatus</it>, no significant differences in wing-length were observed between the single species and co-habitation treatments. Daily survival rates were not significantly different between co-habitation and single species treatments for both <it>An. gambiae </it>s.s. and <it>Cx. quinquefasciatus</it>. Developmental time was found to be significantly different with single species treatments developing better than co-habitation treatments. Sex ratio was found to be significantly different from the proportion of 0.5 among single and co-habitation treatments species at different densities. Single species treatments had more males than females emerging while in co-habitation treatments more females emerged than males. In this study, there was no significant competitive survival advantage in co-habitation.</p> <p>Conclusion</p> <p>These results suggest that co-habitation of <it>An. gambiae </it>s.s. and <it>Cx. quinquefasciatus </it>in semi-natural conditions affect mostly <it>An. gambiae </it>s.s. body size. Hence, more has to be understood on the effects of co-habitation of <it>An. gambiae </it>s.s. and <it>Cx. quinquefasciatus </it>in a natural ecology and its possible consequences in malaria and filariasis epidemiology.</p