Charlotte
Linthout

Project

Track: 13, Vector competence in change scenario’s (Example:: 8, Arbovirus impact in livestock )

Tags

Promotor

Marcel Dicke

Co-promoter(s)

Gorben Pijlman, Ronald van Rij, Barry Rockx

Institute(s)

WUR

E-mail

Telefoon

+32 496 80 21 65

Description PhD project

Vector competence, described as the ability of a vector (in this case a mosquito) to transmit a certain pathogen after blood feeding on an infected host, is known to differ according to biotic and abiotic factors. In light of global warming and environmental change, this project will specifically focus on the impact of these changes on vectors and their capability to transmit arboviruses that form a potential threat to the Netherlands.

Both larval and adult stages of Culex pipiens, Aedes albopictus and Aedes japonicus (model systems for native and invasive mosquito species to the Netherlands) will be exposed to different environmental and climatic challenges in order to assess effects on virus transmission. More specifically, different temperature scenarios that reflect typical Dutch conditions as well as conditions present during unusual hot summers and mild, wet winters with increased night temperatures will be assessed. I will investigate how the mosquito’s immune system responds to these conditions and modulates vector competence by investigating (immune) gene expression in the mosquito.

This work is important for the public health preparedness. Once we know more about which mosquito species are better vectors for flaviviruses, we will be able to more specifically target those mosquitoes during vector control and therefore reduce the risk of spread of mosquito-borne diseases in the Netherlands.


Research questions / objectives

1) What is the effect of different summer regimes on the vector competence of Culex pipiens pipiens, Culex pipiens molestus, Aedes albopictus and Aedes japonicus mosquitoes for selected arboviruses (Table 1)?

2) If there are differences in vector competence between mosquito species, then what are the underlying mechanisms for this?

3) What is the effect of winter conditions on the vector competence of diapausing adult Culex pipiens biotypes?

4) What is the effect of environmental stress factors on larval development and vector competence of mosquito vectors? And what are the underlying mechanisms affecting vector competence?


Timeline


Tags matching with the contents of track 3

Methods

  • Labwork

    • PCR: I use qPCR to identify the biotype of the Cx pipiens complex (pipiens and molestus) to set up a new colony to use it later for my experiments
    • RNA/DNA extraction: I have to extract DNA from mosquitoes to do the qPCR (see above) I will have to work with RNA extraction in the future as soon as I start with infected mosquitoes to see the infection, dissemination and transmission rates.
    • In vivo: Working with Mosquitoes
    • Next generation sequencing (NGS): Will use in the future, not sure yet for which experiment but will clarify this later
    • Ex Vivo: Will probably work with mosquito cell lines
    • Living mosquito experiment: I will infect different mosquito species (Ae albopictus, Ae japonicus and Cx pipiens biotypes) with viruses to investigate their vector competence under different (temperature) scenario’s. I will also work with mosquito larvae and expose them to different stress factors in order to test their vector competence when they are adults.

    Fieldwork

    • Mosquito trapping: I collected Culex egg rafts to set up a new colony and in Lelystad I am collecting Aedes japonicus mosquitoes during summer (June-September) to use in my experiments.

    Literature

    • Literature review: I will do this towards the end of my PhD

Topics

  • Vector:

    • Vector immune response: If we discover differences in vector competence in the different biotypes of the Culex pipiens complex, this could be because of difference in immune response, so this will be investigated
    • Vector susceptibility: During the vector competence studies, also the infection rate of the mosquitoes will be investigated. The question is; if we give them an infected blood meal, is the mosquito then also infected?
    • Vector competence: Different mosquito species will be given an infected bloodmeal and after 14 days under different (climate) conditions, the presence of this virus will be investigated in the saliva of the mosquito

    Environmental:

    • Water: I will test the different stress factors on the larval stages and will then use the adults from these larvae to test vector competence. In that sense I will be working with different water environments (high and low eutrophication).
    • Climate: I will expose infected mosquitoes to different fluctuating and constant temperatures (current and future scenario’s)

    Virus:

    • Virus-mosquito interaction: Investigate how long it takes for a virus to develop in the mosquito

Species

  • Species:

    • Mosquito: I will use different mosquito species for vector competence studies: Culex pipiens pipiens; Culex pipiens molestus; Aedes japonicas; Aedes albopictus

Virus

  • Virus:

    • West Nile virus: Transmission, vector competence
    • Usutu Virus: Transmission, vector competence
    • Japanese Encephalitis Virus: Transmission, vector competence
    • Sindbis Virus: Transmission, vector competence
    • Mayaro Virus: Transmission, vector competence
    • Rift Valley Fever Virus: Transmission, vector competence

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One Health PACT with project number 109986 is (partly) financed by the Dutch Research Council (NWO).