Environmental & Physical Sciences

Research Papers/Topics Environmental & Physical Sciences

Vertical transmission of naturally occurring Bunyamwera and insect-specific flavivirus infections in mosquitoes from islands and mainland shores of Lakes Victoria and Baringo in Kenya

Abstract: Many arboviruses transmitted by mosquitoes have been implicated as causative agents of both human and animal illnesses in East Africa. Although epidemics of arboviral emerging infectious diseases have risen in frequency in recent years, the extent to which mosquitoes maintain pathogens in circulation during inter-epidemic periods is still poorly understood. This study aimed to investigate whether arboviruses may be maintained by vertical transmission via immature life stages of dif...

Metarhizium anisopliae infection reduces Trypanosoma congolense reproduction in Glossina fuscipes fuscipes and its ability to acquire or transmit the parasite

Abstract: Background: Tsetse fly-borne trypanosomiasis remains a significant problem in Africa despite years of interventions and research. The need for new strategies to control and possibly eliminate trypanosomiasis cannot be over-emphasized. Entomopathogenic fungi (EPF) infect their hosts through the cuticle and proliferate within the body of the host causing death in about 3–14 days depending on the concentration. During the infection process, EPF can reduce blood feeding abilities in ...

Sugar-fermenting yeast as an organic source of carbon dioxide to attract the malaria mosquito Anopheles gambiae

Abstract: Background:Carbon dioxide (CO2) plays an important role in the host-seeking process of opportunistic, zoophilic and anthropophilic mosquito species and is, therefore, commonly added to mosquito sampling tools. The African malaria vector Anopheles gambiae sensu strictois attracted to human volatiles augmented by CO2. This study investigated whether CO2, usually supplied from gas cylinders acquired from commercial industry, could be replaced by CO 2 derived from fermenting yeast (yea...

Mosquito Species Succession and Physicochemical Factors Affecting Their Abundance in Rice Fields in Mwea, Kenya

Abstract: The succession of mosquito species and abiotic factors affecting their distribution and abundance in rice (Oryza spp.) Þelds was investigated over a 16-wk rice growing cycle covering the period between January and May 2006. Fifteen experimental rice plots were sampled for mosquito larvae and characterized based on rice height, number of tillers, ßoating vegetation cover, water depth, water temperature, turbidity, salinity, pH, dissolved oxygen, total dissolved solids, and conduct...

Effect of Discriminative Plant-sugar Feeding on the Survival and Fecundity of Anopheles gambiae

Abstract: Background: A previous study showed for Anopheles gambiae s.s. a gradation of feeding preference on common plant species growing in a malaria holoendemic area in western Kenya. The present follow-up study determines whether there is a relationship between the mosquito's preferences and its survival and fecundity. Methods: Groups of mosquitoes were separately given ad libitum opportunity to feed on five of the more preferred plant species (Hamelia patens, Parthenium hysterophorus, R...

Monooxygenase Levels and Knockdown Resistance (kdr) Allele Frequencies in Anopheles Gambiae and Anopheles Arabiensis in Kenya

Abstract: ABSTRACT Pyrethroid-treated bed-nets and indoor spray are important components of malaria control strategies in Kenya. Information on resistance to pyrethroid insecticides in Anopheles gambiae and An. arabiensis populations is essential to the selection of appropriate insecticides and the management of insecticide resistance. Monooxygenase activity and knockdown resistance (kdr) allele frequency are biochemical and molecular indicators of mosquito resistance to pyrethroids. This st...

Mosquito larvicidal constituents from Lantana viburnoides sp viburnoides var kisi (A. rich) Verdc (Verbenaceae)

Abstract: Background & objectives: Lantana viburnoides sp viburnoides var kisi is used in Tanzania ethnobotanically to repel mosquitoes as well as in traditional medicine for stomach ache relief. Bioassay-guided fractionation and subtraction bioassays of the dichloromethane extract of the root barks were carried out in order to identify the bioactive components for controlling Anopheles gambiae s.s. mosquito larvae. Methods: Twenty late III or early IV instar larvae of An. gambiae s.s. were ...

Constant Temperature and time Period Effects on Anopheles gambiae Egg Hatching

Abstract: Anopheles gambiae Giles sensu stricto (Diptera: Culicidae) egg development and its relation to environmental parameters is an understudied aspect of vector biology. Although several studies have illustrated the dramatic effects of temperature on egg development, egg hatching dynamics remain unclear. The objective of this study was to expose An. gambiae eggs to various temperatures for different lengths of time and determine the impact on egg development and hatching count. Batches ...

Bugs with Backpacks Deter Vision-guided Predation by Jumping Spiders

Abstract: As a case study of how insects use masks as a defence against vision-guided predators, an experimental study was carried out using Acanthaspis petax, a reduviid bug (‘ant bug’) that covers itself with a ‘mask’, or ‘backpack’, made from carcasses of its preferred prey (ants), and three salticid spider species, Hyllus sp., Plexippus sp. and Thyene sp., salticids being predators with exceptionally acute vision. The ant bugs and the salticids were from the Lake Victoria reg...

Host plant forensics and olfactory-based detection in Afro-tropical mosquito disease vectors

Abstract: The global spread of vector-borne diseases remains a worrying public health threat, raising the need for development of new combat strategies for vector control. Knowledge of vector ecology can be exploited in this regard, including plant feeding; a critical resource that mosquitoes of both sexes rely on for survival and other metabolic processes. However, the identity of plant species mosquitoes feed on in nature remains largely unknown. By testing the hypothesis about selectivity...

Studies of Transgenic Mosquitoes in Disease-Endemic Countries: Preparation of Containment Facilities

Abstract: Novel approaches to area-wide control of vector species offer promise as additional tools in the fight against vectored diseases. Evaluation of transgenic insect strains aimed at field population control in disease-endemic countries may involve international partnerships and should be done in a stepwise approach, starting with studies in containment facilities. The preparations of both new-build and renovated facilities are described, includingworking with local and national regula...

When it looks and walks like an ant. Learning & Behavior

Abstract: Some jumping spiders (family Salticidae) bear a striking resemblance to ants, a dangerous type of prey, both in terms of their appearance and in terms of how they move. Recent research has taken important steps toward determining whether predators categorize these spiders as ants on the basis of the way they move.

Edible insect value chains in Africa

Abstract: This special issue was organised in the context of the 22nd meeting of the Association of African Insect Scientists (AAIS), in Wad Medani, Sudan in 2017. The aim was to ‘support impactful research that will yield genuine edible insects products and sustain value chains that enhance food and nutritional security and support sustained livelihoods in Africa’. The issue is composed of contributions from the following countries: Kenya, Uganda, Burundi, Nigeria,Mali, Burkina Faso, Ca...

Vision-based Ability of an Ant-mimicking Jumping Spider to Discriminate Between Models, Conspecific Individuals and Prey

Abstract: Myrmarachne assimilis, an ant-like (myrmecomorphic) jumping spider (Araneae, Salticidae) from the Philippines, is a Batesian mimic of Oecophylla smaragdina, the Asian weaver ant. Salticids are well known for their acute eyesight and the elaborate vision-based display behaviour they adopt during encounters with conspecific individuals, but most salticids are not myrmecomorphic. Despite its unusual morphology, M. assimilis adopts display behaviour during intraspecific interactions th...

Spatial panorama of malaria prevalence in Africa under climate change and interventions scenarios. International

Abstract: Background: Malaria is highly sensitive to climatic variables and is strongly infuenced by the presence of vectors in a region that further contribute to parasite development and sustained disease transmission. Mathematical analysis of malaria transmission through the use and application of the value of the basic reproduction number (R0) threshold is an important and useful tool for the understanding of disease patterns. Methods: Temperature dependence aspect of R0 obtained from dy...


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