Texas Tech University

Maria G. Onyango

Assistant Professor
Virology, Medical entomology, Microbiome, Vector - Virus evolution

Email: maonyang@ttu.edu

Phone: 1 (806) 834-7002


  • Bsc. (Biochemistry and Zoology) The University of Nairobi, Kenya
  • Msc. (Applied Parasitology) The University of Nairobi, Kenya
  • PhD. (Veterinary entomology) Deakin University, Australia
  • Postdoctoral training, Yale School of Public Health, Department of Epidemiology of Microbial Diseases
  • Postdoctoral training:
    • Arbovirus Laboratory
    • Wadsworth Center
    • New York State Department of Health
Lab Interests:
  • Dr. Onyango's Lab is interested in understanding mosquito and tick biology and their interaction with viruses. We study the tripartite interactions of arthropods, their microbiome and the pathogens that they transmit and how these interactions may influence disease emergence. Onyango's lab further endeavours to uncover the mechanisms that govern these interactions with the aim of identifying novel ways to block transmission of pathogens as well as discover novel therapeutic agents.

Research Areas

  1. Identification of mechanism of action of Elizabethkingia broad-spectrum antiviral effector molecule

Flavobacteria have been shown to dominate the mosquito midgut including Elizabethkingia (EBK) which is a gram-negative bacillus prevalent in Aedes and Anopheles species of mosquitoes. Aedes aegypti is the primary vector for several important arboviruses including dengue (DENV), chikungunya (CHIKV), yellow fever (YFV) and Zika (ZIKV) viruses. During my postdoctoral training, I have demonstrated that EBK has a broad-spectrum antiviral effect, attenuating the replication of ZIKV, CHIKV and DENV in vitro while significantly reducing ZIKV infection rates of Ae. albopictusin vivo. We aim to define the mechanistic process utilized by EBK to attenuate ZIKV replication. Identification of the effector molecule associated with the antiviral phenotype of EBK could result in a novel transmission barrier tool as well as a therapeutic agent against these viruses.

  1. Analysis of mosquito saliva microbes as transmission barcodes and modulators at the mosquito, pathogen host interface

Most studies of mosquito resistance to viral infection have focused on midgut infection stages of the virus although it is not the sole location of the microbiome impact on viral replication. Microbes in the salivary gland of mosquitoes has been reported. Our results to date convincingly show the presence of microbes in the saliva of Ae. albopictus. A knowledge gap exists on how the mosquito microbiome interacts with the salivary gland and saliva and how this may modulate transmission of pathogen and the role of mosquito salivary microbes in vertebrate host pathogenicity. The identification of role played by saliva microbiome at the bite site and their interaction with vertebrate host keratinocytes  will lead to a deeper understanding of disease immunopathology and may lead to new therapeutics. We aim to utilize animal models to delineate the impact of mosquito saliva microbes on transmission, the early events, progression and the severity of mosquito-borne pathogens in the vertebrate host. Further, we aim to analyze the composition of populations of wild mosquitosalivary microbiome and develop saliva barcodes as a risk assessment tool for Dengue outbreaks in Kenya. Identification of Aedes mosquito salivary microbial profile that could act as a ‘barcode' predictive of specific Aedes population efficiency in DENV transmission which can be utilized by policy makers to efficiently distribute resources for DENV management.

  1. Determining the effects of vector, pathogen, ecology interactions and its impact on disease emergence in Africa

Despite the fact that arbovirus outbreaks of global importance often originate from sylvatic spillover on the African continent and subsequent movement to new continents, scarce attention is paid to understanding the origins of arboviruses in Africa. There is a need to understand the interactions of the vector and the virus in unique urban, sylvatic and transition ecological zones in sub-Saharan Africa and how these interactions lead to spillover events as well as evolution of arboviruses.

We aim to assess transmission dynamics and spillover risks of tick and mosquito-borne pathogens in unique ecological units in Ugandan cattle corridor, Kenyan-Uganda border, coastal Kenya and arid north Kenya. We will characterize arthropod species diversity in diverse ecosystem, their competence for specific viruses as well as characterize their virome. In addition, the vectorial capacity of the Aedes vectors transmitting the viral genotypes at these unique ecological zones will be assessed and the interactions between host and pathogen genotypes will be studied. Identification of the incidence of tick and mosquito-borne pathogens in Ugandan cattle corridor and Kenyan arid north will provide detailed information on the species of ticks and mosquitoes competent for various arboviruses as well as the identification of novel viruses transmitted by mosquitoes and ticks in these regions. The results of our study will result in innovative, targeted resource-allocation and vector control strategies that could ultimately serve as a template for future continental scale analysis. 

Recent Publications

  • Onyango MG, Bialoskunia S, Payne A, Mathias N, Ciota At, Kramer LD, 2020, Increase in temperature enriches heat tolerant taxa in Aedes aegypti midguts, Scientific Reports
  • Onyango MG, Attardo GM, Taylor, ET, Bialosuknia S, Stout J, Banker E, Kuo L, Ciota AT, Kramer LD, 2020, Zika Virus infection results in biochemical changes associated with RNA editing, Inflammatory and antiviral responses in Aedes albopictus, Frontiers in Microbiology
  • Onyango MG, Ciota AT, Kramer LD, 2020, The vector host pathogen interface: The next frontier in the battle against mosquito-borne viral diseases? Frontiers Cell Infection Microbiology
  • Onyango MG, Bialoskunia Sean, Payne Ann, Mathias Nicholas, Kuo Lilli, Vigneron Aurelien, DeGennaro Matthew, Ciota Alexander T and Kramer Laura D, 2020, Increased temperatures reduce the vectorial capacity of Aedes mosquitoes for Zika virus, Emerging Microbes and Infections 9(1):66-77
  • I Schneider *, Norah Saarman *, Onyango MG * ,Chaz Hyseni, Robert Opiro, Richard Echodu, Michelle O'Neill, Danielle Bloch, Aurelien Vigneron, T.J. Johnson, Kirstin Dion, Brian L. Weiss, Elizabeth Opiyo, Adalgasia Caccone and Serap Aksoy, 2019, Spatio-temporal distribution of Spiroplasma infections in the tsetse fly (Glossina fuscipes fuscipes) in northern Uganda Plos Neglected Tropical Diseases 13 (8) [*- Equal contribution].
  • Onyango MG, Nicola C.A, Cameron j et al. (2016), Genotyping of whole genome amplifiedreduced representation libraries reveals a cryptic population of Culicoides brevitarsis in the Northern Territory, Australia. BMC Genomics 17:769
  • Onyango MG, Beebe NW, Gopurenko D et al. (2015) Assessment of population genetic structurein the arbovirus vector midge, Culicoides brevitarsis (Diptera: Ceratopogonidae), using multi-locus DNA microsatellites. Veterinary Research, 46, 108.
  • Onyango MG, Michuki GN, Ogugo M et al. (2015) Delineation of the population geneticstructure of Culicoides imicola in East and South Africa. Parasites & Vectors, 8, 660
  • Charles Masembe, George Michuki, Onyango MG, Cecilia Rumberia, Richard P. Bishop, Appolinaire Djikeng, Stephen J. Kemp, Alan Orth, Robert Skilton, Karl Stahl and Anne Fischer, (2012) Viral metagenomics demonstrates that domestic pigs are a potential reservoir for Ndumu Virus, Virology 9:218

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