Biology subjects

Kinyua, J.

Publications and source records attributed to Kinyua, J..

4 recordsLinked to original sources

bioRxiv2026

Isolation and characterisation of novel fruit bat alphaherpesvirus from Rousettus aegyptiacus bats in Coastal Kenya

BackgroundHerpesviruses are a group of double-stranded DNA viruses known to infect a wide range of vertebrates and establish life-long latent infections. While bats serve as natural reservoir hosts for numerous viral families, relatively few bat herpesviruses have been successfully isolated. In this study, we report the isolation and characterization of two novel alphaherpesvirus strains obtained from Rousettus aegyptiacus bats in Coastal Kenya. MethodsThe samples of oral and rectal swabs were collected from three different species of bats from coastal Kenya between October 2024 and April 2025; the bat species collected include Hipposideros spp., Coleura afra, and Rousettus aegyptiacus. Virus isolation was performed by inoculation of samples in Vero E6 cells and subsequent monitoring for cytopathic effects (CPE). Total nucleic acids were extracted from CPE positive cultures and subjected to library preparation to enable unbiased detection of both RNA and DNA viruses. The libraries were sequenced using next-generation sequencing with Illumina MiSeq platform. Subsequently, bioinformatic analysis was carried out to identify the virus, generate consensus genomes as well as phylogenetic analysis to determine the placement of identified viruses. ResultsTwo samples from R. aegyptiacus (KIK_460_O and KIK_465_O) induced typical CPE within five days. Sequencing and assembly yielded partial consensus sequences of approximately 60 kb (KIK_460_O) and 70 kb (KIK_465_O), representing extended genomic data for a bat-associated alphaherpesvirus. This virus has a genome of about 140kb, indicating that our partial assemblies account for about 43-50% of the total genome. Both isolates were found to be closely related to Dzifa herpesvirus, an alphaherpesvirus previously identified in Kilifi, Kenya. Alphaherpesvirus was identified based on partial sequencing of UL19 (3,787bp) and UL30 (2,846bp) genes. The two isolates were found to be identical at the UL19 gene, showing that they belonged to the same virus strain. Phylogenetic analysis showed that the novel alphaherpesvirus belongs to primate alphaherpesviruses under the subfamily Alphaherpesvirinae. ConclusionThis study reports the isolation and genomic characterization of a novel fruit bat alphaherpesvirus from Kenyan Rousettus aegyptiacus bats. The partial genome assembly (60-70 kb) represent the first extended genomic data for this virus, covering approximately 43-50% of the estimated 140 kb complete genome. The phylogenetic placement of this alphaherpesvirus near primate viruses, especially Pteropodid alphaherpesvirus 1, suggests bat-association and needs further investigation into its zoonotic potential.

microbiology↗

bioRxiv2025

Human-Mediated Dispersal and Breeding Reshape Global Genomic Patterns in Black Soldier Flies

Human activities, either intentional or unintentional, have significantly influenced the global distribution and genetic composition of many species. Black soldier fly (Hermetia illucens; BSF) is a species that has rapidly gained commercial importance due to its bioconversion efficiency of upcycling organic waste into new products of higher value and quality through a circular economy approach. Despite its global distribution, the current Old-World demography of the wild and captive BSF populations remains poorly understood. This work combined whole-genome sequencing and population genomic analyses to determine the genetic diversity, population structure, and historical spread of global wild and captive BSF populations. Our results reveal that most global captive BSF lines were largely derived from a single primary captive lineage, likely from North America. In contrast to the genetically diverse and geographically structured wild populations, captive populations consistently exhibited reduced heterozygosity, elevated inbreeding, and extensive runs of homozygosity. These patterns reflect demographic processes such as founder effects and genetic drift, rather than intentional selection or domestication. This strongly highlights the lasting genomic impact of human-mediated dispersal and uncoordinated breeding practices. Thus, there is an urgent need for genetically informed management strategies to ensure long-term viability, adaptability, and productivity of BSF for sustainable organic waste bioconversion.

genomics↗

bioRxiv2025

Identification and genetic characterization of Jingmen tick virus from ticks sampled in select regions of Kenya; 2022-2024

Jingmen tick virus (JMTV), an emerging segmented RNA virus classified as an ungrouped flavivirus, poses a growing public health concern globally. Known for its association with febrile illnesses and wide host range, JMTV has been detected in Rhipicephalus, Hyalomma, and Amblyomma ticks collected from cattle, goats, sheep, camels, and chickens in pastoral regions of Kenya, including Baringo, Mandera, Malindi, Lamu, Mombasa, Wajir, Isiolo, and West Pokot. Using viral metagenomics next-generation sequencing, this study analysed adult ticks (n=1547, 72 pools). A total of 53% (38/72) pools were positive for at least one viral pathogen, with JMTV detected in 87% (33/38) of these pools across all study sites. Phylogenetic analyses revealed evidence of distinct Kenyan JMTV strains, with sequence segments from Malindi and Wajir clustering uniquely in their own clade; suggesting potential localised evolutionary pressures. Time calibrated phylogeny for the segment 1(RdRp) suggested varied ancestral origins and evolutionary relationships for the JMTV strains. MEME, BUSTED and FUBAR methods implemented in the Data-Monkey, unanimously identified codon 290 in segment 1 and 30 in segment 4 to be undergoing episodic positive selection. Recombination analysis performed using the RDP4 recombination detection tool indicated a recombination event in segment 2 of the Lamu JMTV strain that was confirmed by seven detection methods and visualised in BootScan. These findings suggest that Kenyan JMTV strains are undergoing positive selection, potentially driven by unique ecological and host factors. Segmented genome evidence of recombination highlights the increasing viruss potential for antigenic diversity. Host diversity and virus phylogenetic patterns underscore the zoonotic potential and its capacity for regional spread, emphasizing the critical need for enhanced vector surveillance. Temporal and ecological drivers like seasonal tick activity and livestock movement warrant investigation to elucidate JMTV transmission dynamics. Prioritizing tick-borne virus surveillance in Kenya will strengthen public health strategies and mitigates emerging viral risks.

evolutionary biology↗

bioRxiv2023

Silver nanoparticle biosynthesis utilizing Ocimum kilimandscharicum leaf extract and assessment of its antibacterial activity against certain chosen bacteria

Using plants in the biological production of silver nanoparticles (AgNPs) is becoming increasingly important as a practical and environmentally benign method. In the current work, silver nanoparticles were made utilizing the significant Ocimum kilimandscharicum, and their potential to combat certain bacteria was discussed. Both aqueous and methanol plant extracts were used for reducing silver nitrate at different time intervals (30 to 150 minutes) and pH (2 to 11). The UV-visible absorption spectrum recorded for both methanol and aqueous extracts revealed successful synthesis of AgNPs. The antimicrobial activity of the AgNPs was evaluated against Escherichia coli ATCC 25922, Salmonella choleraesuius ATCC 10708, and Staphylococcus aureus ATCC 25923. 50mg/ml was the concentration of the extracts tested. The best zone of inhibition was recorded for the methanol and aqueous-mediated AgNPs, ranging from 12{+/-}1 to 16{+/-}1mm. The methanol and aqueous extract silver nanoparticles had the same Minimum Inhibitory Concentration (6.25{+/-}0.00 mg/ml), whereas the Minimum Bactericidal Concentrations were 12.5{+/-}0.00 and 25{+/-}0.00 mg/ml, respectively. The highest inhibition zone of 16{+/-}1 mm was observed against Salmonella choleraesuius with 50{+/-}0.00 mg/ml aqueous silver nanoparticles. The results show that the silver nanoparticles made with Ocimum kilimandscharicum have potent antibacterial action against those microorganisms.

pharmacology and toxicology↗