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Phleboviruses are emerging pathogens of public health importance. However, their association with ticks is poorly described, particularly in Africa. Here, adult ticks infesting cattle, goats and sheep were collected in two dryland pastoralist ecosystems of Kenya (Baringo and Kajiado counties) and were screened for infection with phleboviruses. Ticks mainly belonged to the species Rhipicephalus appendiculatus, Hyalomma impeltatum, and Hyalomma rufipes. A fragment of the RNA-dependent RNA polymerase (RdRp) gene was identified in thirty of 671 tick pools, of which twenty-nine were from livestock sampled in Baringo county. Phylogenetic analyses revealed that twenty-five sequences were falling in three clades within the group of tick-associated phleboviruses. The sequences of the three clades showed nucleotide distances 8%, 19% and 22%, respectively, to previously known viruses suggesting that these sequence fragments may belong to three distinct viruses. Viruses of the group of tick-associated phleboviruses have been found in several countries and continents but so far have not been associated with disease in humans or animals. In addition, five sequences were found to group with the sandfly-associated phleboviruses Bogoria virus, Perkerra virus and Ntepes virus recently detected in the same region. Further studies are needed to investigate the transmission and maintenance cycles of these viruses, as well as to assess their potential to infect vertebrates.

Aedes aegypti is the primary vector of dengue, chikungunya, and Zika viruses of medical importance. Behavioral and biological attributes contribute to its vectorial capacity. The mosquito domestic form, which resides outside Africa (Ae. aegypti aegypti (Aaa)), is considered to breed in artificial containers in and around homes and preferentially feeds on human blood but commonly indulges in a plant diet. Potential divergence in these attributes, in sub-Saharan Africa (SSA) where Aaa coexists with the forest ecotype (Ae. aegypti formosus), should impact the vectoring ability and hence disease epidemiology. A summary of current knowledge on Ae. aegypti blood feeding, oviposition, and plant-feeding habits among SSA populations is provided in comparison with those in different geographies, globally. Emphasis is placed on improved understanding of the connection between changing subspecies adaptation in these traits and arbovirus disease risk in SSA in response to climate change and increasing urbanization, with the ultimate use of this information for effective disease control.

Thymol as a natural biological template can be modified chemically since the hydroxyl group makes it a candidate for structural modification. Thus, this study incorporated the triazole moiety on thymol and the chlorination of thymol moiety to help improve its biological potency.A series of ten 1,2,3-triazole-thymol derivativesAll the synthesized triazole-thymol derivatives showed significant but variable antibacterial activity against the seven medically important bacterial strains tested. The compound 4-((4-chloro-2-isopropyl-5-methylphenoxy)methyl)-1-(2-nitrobenzyl)-1These results provide additional evidence of the exploitation of natural products like thymol as leads for drug development against medically important bacterial pathogens.

The leaf essential oils from Cupressus lusitanica, Miller and Eucalyptus saligna, Smith obtained by hydrodistillation were analyzed by GC/MS and also screened for their insecticidal and repellent effects against adult Tribolium castaneum, Acanthoscelides obtectus, Sitotroga cerealella and Sitophilus zeamais. The C. lusitanica oil contained mainly umbellulone (18.38%) and α-pinene (9.97%) whereas the E. saligna oil was dominated by α-pinene (24.40%) and 1,8-cineole (24.26%). Bioassays showed that of the four insect species tested, A. obtectus and S. cerealella were the most susceptible to the oils, with LC50 values of 0.05–0.11% v/w in contact toxicity and 4.07–7.02 μl/L air in space fumigation. Except in T. castaneum with percentage repellence (PR) values of 65–92.5%, the other test insects recorded PR values less than 30%. The PR values decreased with exposure time in all insects except in T. castaneum. Our results show that C. lusitanica and E. saligna essential oils are promising insecticides and repellents to be used against insect pests of stored food grains.

Soybean (Glycine max L.) is among the most economically important legumes that provide more than 1/4 of food (for man) and animal feed. However, its yield is comparatively low, most especially under drought stress. The aim of this study therefore was to assess the ability of Rhizobium spp. and mycorrhizal fungi to enhance the yield, seed size and fatty acid content of soybean grown under semi-arid environment. Rhizobium sp. strain R1 was found to possess nitrogen-fixing gene coniferyl aldehyde dehydrogenase function while Rhizobium cellulosilyticum strain R3 was found to have nitrogen-fixing genes cysteine desulfurase SufS and cysteine desulfurase IscS activity. Soybean (Glycine max L) seeds inoculated with Rhizobium spp. and mycorrhizal fungi were cultivated in soil exposed to drought stress. Rhizobium spp. inoculation and mycorrhization alleviate drought stress and increase yield, size and fat content of soybean seeds. This increase in the aboveground parameters was accompanied with an increase in belowground mycorrhizal spore number, percentage root mycorrhization and aboveground shoot relative water content (RWC) in the dually inoculated (R1 + R3MY) soybean plants. In particular, the dually inoculated (R1 + R3MY) soybean plants revealed 34.3 g fresh weight, 15.1 g dry weight and soybean plants singly inoculated with Rhizobium sp. strain R1 (R1) produced more large seeds with 12.03 g dry weight. The non-inoculated (control) seeds contained a higher percentage of moisture content compared to the microbially amended seeds while seeds co-inoculated with Rhizobium cellulosilyticum strain R3 and mycorrhizal consortium revealed the highest percent (8.4 %) of fat. Several fatty acids that are of significant health benefits to humans were observed in the soybean seeds. In order to gain insights into the bacterial communities of rhizospheric soil collected at different stages of soybean growth, class-based Heat-map analysis was performed on the Miseq sequenced data. The core bacteria that were found in the rhizospheric soil were Verrumicrobia, Proteobacteria, Gemmatimonadetes, Firmicutes, Cyanobacteria, Chloroflexi, Bacteroidetes, Actinobacteria, Acidobacteria, Planctomycetes, Deinococcus thermus and Nitrospira suggesting that the rhizobia and fungi used in this study can also improve soil microbial diversity.

The unintended release of chemicals to the environment has led to global concern on water quality prompting widespread research on the occurrence of these compounds in water. While increasing information on organic micropollutants (OMPs) in European water resources is available, there is still limited information on the occurrence of OMPs in African water systems. In this study, a multi-residue analysis covering 428 chemicals using liquid chromatography coupled to high resolution mass spectrometry (LC-HRMS) was performed on water samples collected from 48 surface water sites within the Lake Victoria South Basin, Kenya. A total of 75 compounds including pharmaceuticals, personal care products (PPCPs), pesticides, and industrial chemicals were detected and an additional three compounds (nevirapine, lamivudine and adenosine) were identified through suspect screening. Four compounds including diphenhydramine, simazine, triethylphosphate and acetyl-sulfamethoxazole (A-SMX) were detected in >80% of the sites showing their ubiquitous nature in the study area. Individual compound concentrations were detected up to 24 μg L−1. Concentrations above 1 μg L−1 were also reported for triethylcitrate, N-ethyl-o-toluenesulfonamide, hexazinone, nevirapine, adenosine and carbendazim. While crustaceans were potentially the taxon at risk for acute toxicity (toxic unit (TU) up to 2) with diazinon driving this risk, lower but substantial acute risk (TU 0.5) was observed for algae. Chronic risks were observed in 11 sites for algae (TU > 0.02) and in 5 sites for fish (TU > 0.01). A total of 16 compounds were prioritized based on frequency and extent of the exceedance of thresholds for acute and chronic risks to algae, crustaceans and fish and another 7 compounds prioritized by applying lowest Predicted No-Effect Concentrations (PNEC). Based on these indicators, this study provides candidate priority compounds for monitoring, assessment and abatement in western Kenya.

Linalool oxide (LO) and hexanoic acid (HA) represent plant- and human-derived odorants, respectively, previously found as attractants for the dengue vector Aedes aegypti. Here, we investigated if a blend of both compounds can improve captures of this mosquito species in field trials in two dengue endemic sites, Kilifi and Busia Counties in Kenya. Ae. aegypti captures were significantly higher in Kilifi than Busia (χ21,142 = 170.63, P

Summary Plasmodium parasites are known to manipulate the behavior of their vectors so as to enhance transmission [1–4]. From an evolutionary standpoint, behavior manipulation by the parasite should expose the vector to limited risk of early mortality while ensuring sufficient energy supply for both it and the vector [5, 6]. However, it is unknown whether this vector manipulation also affects vector-plant interaction and sugar uptake. Here, we show that the attraction of Anopheles gambiae s.s. to plant odors increased by 30% and 24% after infection with the oocyst and sporozoite stages of Plasmodium falciparum , respectively, while probing activity increased by 77% and 80%, respectively, when the vectors were infected with the two stages of the parasite. Our data also reveal an increased sugar uptake at the oocyst stage that decreased at the sporozoite stage of infection compared to uninfected An. gambiae , with depletion of lipid reserves at the sporozoite stage. These results point to a possible physiological adjustment by An. gambiae to P. falciparum infection or behavior manipulation of An. gambiae by P. falciparum to enhance transmission. We conclude that the nectar-seeking behavior of P. falciparum- infected An. gambiae appears to be modified in a manner governed by the vector's fight for survival and the parasite's need to advance its transmission.

Essential oils from leaves and berries of Solanum sarrachoides were obtained by hydro-distillation, analyzed by GC–MS and tested for oviposition deterrence against Tetranychus evansi . Plant oils comprised mainly of monoterpenes and fatty acids, but differed in terms of their relative abundance. The leaf oil contained mainly camphor (34.1%), limonene (8%), decanoic acid (9.3%) and hexadecanoic acid (7.3%). The berry oil contained mainly fatty acids (>20%) including hexadecanoic acid (9.8%) and dodecanoic acid (5.9%), hydrocarbons (>10%) and ( E )-β-linalool (3.1%). In oviposition deterrence assays, the leaf essential oil and individual major monoterpenes compared favorably with the two positive controls, neem oil and cinnamaldehyde at varying concentrations [incidence ratio (IR) S. sarrachoides and their monoterpene constituents play a role in regulating oviposition in T. evansi .

Isoschaftoside, an allelopathic di-C-glycosylflavone from Desmodium spp. root exudates, is biosynthesised through sequential glucosylation and arabinosylation of 2-hydroxynaringenin with UDP-glucose and UDP-arabinose. Complete conversion to the flavone requires chemical dehydration implying a dehydratase enzyme has a role in vivo to complete the biosynthesis. The C-glucosyltransferase has been partially characterised and its activity demonstrated in highly purified fractions.

Five novel limonoids, 1-5, were isolated from the root bark of Turraea wakefieldii and were characterized as tecleaninoid derivatives. This is the first report of the natural occurrence of tecleanin-type limonoids with a five-membered-ring A-seco structure for which we propose the name neotecleanins. The relative stereochemical structures of compounds 1-5 were established on the basis of NMR spectroscopy. The absolute stereochemical structure of 5 was confirmed by X-ray diffraction methods. In mosquito larvicidal assays, compounds 1, 2 and 4 showed dose-dependent larvicidal activity against larvae of Anopheles gambiae s.s.

We have studied the effect of shifting the desert locust, Schistocerca gregaria (Forskal) from crowded to solitary conditions, or vice versa on the emission of the adult aggregation pheromone (as measured by released phenylacetonitrile) and compared this with changes in morphometrics. Adult males of the F0 generation resulting from shifting crowd-reared (gregarious) hoppers, fledglings or mature adults (aged 20–22 days after the final moult) to solitary conditions did not produce phenylacetonitrile, similar to solitary-reared adults. Conversely, adults of the F0 generation resulting from shifting solitary-reared (solitarious) hoppers, fledglings or mature adults to crowded conditions produced pheromone at levels which were not significantly different from those of control adults from the crowd-reared colony. The levels of pheromone increased in the F1 generation but decreased and leveled off in the F2 and F3 generations. Extreme sensitivity to crowding was demonstrated by the fact that even pairing of one solitarious hopper with another produced F0 adult males that produced phenylacetonitrile, although in significantly lesser amounts than by males reared at a density of four per cage or by crowd-reared control males. In contrast, morphometrics changes were slow and required several generations. The FC ratio (hind-femur length to head capsule width) was more sensitive to treatment effects than the EF ratio (fore-wing to hind-femur length), in agreement with previous findings. We conclude that pheromone titres are a more sensitive measure than morphometrics to determine the onset of phase change in the desert locust.

Extracts of the root bark of Turraea floribunda have yielded four new limonoids of the havanensin class: 28-nor-4α-carbomethoxy-11β-acetoxy-12α-(2-methylbutanoyloxy)-14,15-deoxyhavanensin-1,7-diacetate; 28-nor-4α-carbomethoxy-11β-hydroxy-12α-(2-methylbutanoyloxy)-14,15-deoxyhavanensin-1,7-diacetate; 18-nor-4α-carbomethoxy-11β-acetoxy-12α-(2-methylbutanoyloxy)-14,15-deoxyhavanensin-1-acetate; and 28-nor-4α-carbomethoxy-7-deoxy-7-oxo-11β-acetoxy-12α-(2-methylbutanoyloxy)-14,15-deoxyhavanensin-1-acetate. The structures were determined by spectroscopic methods. The structure for the first of these compounds was also confirmed by X-ray diffraction methods.

A novel sesquiterpene (mutangin) of the eudesmane type with five hydroxyl functions has been isolated from unripe fruits of Elaeodendron buchananii