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Mosquitoes play a predominant role as leading agents in the spread of vector-borne diseases and the consequent mortality in humans. Despite reports on increase of new and recurrent mosquito borne-disease outbreaks such as chikungunya, dengue fever and Rift Valley fever in Kenya, little is known about the genetic characteristics and diversity of the vector species that have been incriminated in transmission of disease pathogens. In this study, mosquito species were collected from Kisumu city, Kilifi town and Nairobi city and we determined their genetic diversity and phylogenetic relationships. PCR was used to amplify the partial cytochrome oxidase subunit 1 (CO1) gene of mosquito samples. Molecular-genetic and phylogenetic analysis of the partial cytochrome oxidase subunit 1 (CO1) gene were employed to identify their relationship with known mosquito species. Fourteen (14) haplotypes belonging to genusAedes, nine (9) haplotypes belonging to genusAnophelesand twelve (12) haplotypes belonging to genusCulexwere identified in this study. Findings from this study revealed a potentially new haplotype belonging toAnophelesgenus and reported the first molecular characterization ofAedes cumminsiiin Kenya. Sequence results revealed variation in mosquito species from Kilifi, Kisumu and Nairobi. Since vector competence varies greatly across species as well as species-complexes and is strongly associated with specific behavioural adaptations, proper species identification is important for vector control programs.

Ticks are important arthropod vectors of diseases of man and farm animals in Africa and in spite of the efforts to control them using synthetic acaricides, they continue to be amongst the leading vectors of disease-causing agents. Unfortunately, over-reliance on synthetic acaricides for tick control has led to problems including acaricide resistance, environmental pollution, and acaricide residues in products destined for human consumption. These problems highlight the need for alternative tick control methods that are environment friendly and yet effective. In the current study, the repellency and toxic effects of essential oils extracted from four Kenyan plants namely;Tagetes minuta L.(Asteraceae), Fuerstia. africana T.C.E. Friers (Lamiaceae), Tephrosia vogelii Hook. f. (Leguminosae) and Sphaeranthus ukambensis against the ixodid tick Rhipicephalus appendiculatu were determined. Essential oils were extracted by steam distillation from fresh plants using Clevenger apparatus. Host seeking nymphs (2-3 weeks old)and adult ticks were used and fumigant toxicity bioassay was done using four concentrations (0.1µ/ml, 0.01 µ/ml, 0.001 µ/ml, and 0.0001µ/ml) of the essential oils, each in four replicates and with ten ticks per replicate. In the control experiment, ticks were exposed to n- hexane. Mortality was recorded every 48 hours for 2 weeks. In repellency bioassay, a Y tube olfactometer and same concentrations as above were used. Treated paper discs were placed in one arm and control (discs treated with hexane) in the other. Ticks were introduced at the main arm and allowed to make choices on the direction of movement. Ticks on the two arms were counted after 30 minutes. The essential oils showed dose dependant mortality and repellency values. The highest repellency value for R. appendiculatus adults was observed with T. vogelii (93.8% at 0.01µ/ml) while for the nymphs, both S. ukambensis and T. vogelii recorded the highest repellency values of 100% and 95% respectively both at 0.1µ/ml concentration. Essential oils from Fuerstia. africana recorded the highest mortality values for nymph (97.8% at 0.1µ/ml) and adult (53.2 % 0.1µ/ml) Rhipicephalus appendiculatus . The present study has demonstrated that Tephrosia vogelii, Tagetes minuta and Sphaeranthus ukambensis have repellent and toxic effects on Rhipicephalus appendiculatus and therefore can

Essential oils are complex mixtures of odours and steam volatile compounds which are deposited by plants in the subcuticular space of glandular hairs, in excretory cavities and canals or exceptionally in heart wood. Essential oils have been found to have no specific biological functions in plants, but constitute many compounds that are insect repellents or act to alter insect feeding behavior, growth and development, ecdysis (moulting) and behavior during mating and oviposition. Others possess antifungal, insecticidal and antiseptic properties. Essential oils of leaves of Tagetes minuta L. (Asteraceae), Fuerstia africana T.C.E. Friers (Labiaae), Tephrosia vogelii Hook. f. (Leguminosae) and Sphaeranthus ukambensis were obtained by steam distillation using the Clevenger apparatus (Guenter, 1949). Compounds in the essential oils were identified by gas chromatography-mass spectrometry (GC-MS). The characteristic volatiles isolated from the four plants were identified as follows: major constituents of the essential oils from F. africana included the following: limonene (39.1%), (Z)-β-ocimene (30.5%), targetone (26.2%), E -targetone (59%), λ-terpinene (26.2 %), peripitenone 23.7%, ocimene allo (22.8%) and Z-targetone (100%). The compounds with the highest relative abundance value in the essential oils included Z-targetone, E-targetone and (Z)-β-Ocimene. Analysis of T. minuta also revealed a number of compounds which included mycene (20.1%), verbinene (8.0%), Z-ocimenone (35.2%), E-caryophylene (25.5%), α-Humelene (11.8%), germacrene D (21.4%) and camphene (2%). The major constituent of T. minuta was Z-ocimene, caryophylene E and mycene. Essential oils from T. vogelii as revealed by the GC-MS analysis were pinene α (32.7%), limonene (35.1%), copaene α (22.9%), β -elemene (36.7%), Z-nerolidol (77.7%), δ-cadinene (67.6%), α humelene (69.6%) and -4-α-ol-(β)copaene (65.7%). The highest proportion of the essential oils constituted Z- nerolidol δ-cadinene, α-humelene and 4-α-ol-β. Copaene. The compounds in essential oils obtained from S. ukambensis were α-copaene (23.8%), β-bourbonene (25.5%), α-gurjunene (14.3%), cymene