Zoek medewerkers/organisaties dr. HJ Esser MSc BSc
Naam
Naamdr. HJ Esser MSc BSc
RoepnaamHelen
Emailhelen.esser@wur.nl

Werk
OmschrijvingOnderzoeker
OrganisatieDepartement Plantenwetenschappen
OrganisatieeenheidLaboratorium voor Entomologie
Telefoon
Mobiel
Telefoon secretariaat+31 317 484 075
Telefoon 2
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BezoekadresDroevendaalsesteeg 1
6708PB, WAGENINGEN
Gebouw/Kamer107/W0.Aa.081
Postadres
Bodenummer
Reguliere werkdagen
Ma Di Wo Do Vr
Ochtend
Middag

Biografie

I'm disease ecologist with a strong interest in ticks and tick-borne diseases. My PhD project focussed on ecological interactions between communities of ticks, wildlife, and tick-borne pathogens in the tropical forests of Panama, and how wildlife diversity loss may impact these interactions. I was also involved in the Eco-Alert project, for which I reviewed ecological risk factors associated with arbovirus circulation, such as the availability of suitable hosts, vectors, habitat, and favorable climatic conditions. Based on these risk factors, we performed a spatial risk analysis for the Netherlands to help identify areas with the highest potential for endemic circulation of 6 arboviruses. Currently, I'm working as a postdoctoral researcher at the Laboratory of Entomology, where I study the transmission dynamics and ecology of tick-borne encephalitis virus in the Netherlands.

More about my research

 


Expertiseprofiel
Expertise

Publicaties
Publicatielijsten

Projecten

TBEV: Contributions to Monitoring, Early Warning and Intervention in The Netherlands (TBEV-COMEIN)

Tick-borne encephalitis virus (TBEV) is among the most important vector-borne diseases in Europe and Eurasia. Both the distribution and number of cases have increased during the past decades, prompting questions regarding the ecological factors that contribute to the sustained circulation and spread of this virus. Recently, TBEV emerged in the Netherlands, with the first two autochthonous cases reported in summer 2016. In the current project, we aim to understand how factors such as microclimate, wildlife community structure, host reservoir competence, and co-feeding are involved in the transmission dynamics and ecology of TBEV. In addition, we will determine TBEV prevalence in wildlife and identify high risk areas in the Netherlands.

 

PhD project: Wildlife diversity loss and the emergence of tick-borne diseases in central Panama

Habitat destruction, fragmentation and hunting are among the major drivers of the global biodiversity crisis. An urgent question is how the ongoing loss of species will affect the functioning of ecosystems and the benefits that humans obtain from their natural environment. One such ecosystem service that might be affected is the control of infectious diseases. Loss of wildlife may disrupt complex ecological interactions between pathogens, vectors and hosts, potentially triggering disease emergence in both humans and animals. Hence, a better understanding of how vectors respond to alterations in host community composition and the consequences for pathogen prevalence is critically important.

I study the associations between rickettsias, ticks, and vertebrates, and how wildlife diversity loss affects these interactions. I address this fundamental issue using a community-wide approach; that is, rather than focusing on single-species interactions, I consider broader communities of hosts, ticks and microbes in central Panama. I hypothesize that most tick species in this diverse system are highly host specific in the adult (reproductive) stage, just few are generalists. As a consequence, ticks should be sensitive to coextinction with their hosts. Specifically, specialist ticks should disappear when their specific host species are lost, whereas generalist ticks are able to persist in even the most impoverished wildlife communities. Similarly, the diversity of rickettsias and other microbes - including symbionts and pathogens - should be higher in larger, richer tick communities, and decrease with loss of tick species richness. Although a decrease in tick and microbial diversity with wildlife diversity loss might intuitively sound appealing, most pathogenic microbes are transmitted by generalist ticks. Not only are generalist ticks able to survive in species-poor communities, they may also feed disproportionally more from disease reservoir hosts in such degraded environments, so that increased "generality" of tick communities should increase disease risk.

Fieldwork is carried-out at 20 sites across central Panama that constitute a gradient in wildlife diversity and abundance. I use 1) arrays of motion-sensitive camera traps to assess the community composition of wildlife; 2) drag sampling to collect questing ticks (i.e. those in search of a host); and 3) live trapping of small mammals to directly collect ticks, blood and feces from vertebrate hosts. Using advanced molecular tools, I will identify ticks to species and determine the total microbial diversity within these ticks for each site. 

This study will increase fundamental insight into host-tick-pathogen interactions and increase awareness of how anthropogenic disturbance of the natural environment (through wildlife diversity loss) can impact human health. 


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