Research

**This page is currently under construction. Thank you for your patience!**

Research Philosophy

The four main tenets of my work are:

1. Question-driven science

When working with students, I often feel like a broken record, because it always comes down to this- What’s your research question?  I believe that almost any conundrum in a project can be solved by going back to your research question. Lost in your data? What’s your research question? Can’t figure out how to design your experiment? What’s your research question? Which graph to include in the paper? What’s your research question? How to structure your manusrcipt? What to cover in the introduction? What to discuss in the discussion? What to put in your powerpoint? You get the idea…

2. Science for a reason

I do not do science in a bubble nor to make me feel really smart. I was never a kid who took alarm clocks apart just to see all the pieces and then put them back together. (For the younger generation- an alarm clock was a small piece of machinery we used to help us wake up in the morning).This is not to say that curiousity is not important nor that understanding the role of every piece of a system is not important. However, in my work, every project I get behind must have the possibility, however minute, of having a positive impact on human society, conservation, the environment, or all of the above- even if it is just a drop in the proverbial bucket (as PhD theses often are- see below to read about my doctoral drop in the bucket)

3. Clarity first

The most important thing we do as scientists is communicating our work CLEARLY to non scientists. If no one understands what you did and what it means in the context of the world, what is the point? Which brings me to my final point…

4. Science is not just for scientists!

Need I say more?

 

Current Projects

 

Eco-epidemiology of disease transmission in Arequipa, Peru

EpiReportR: an epidemiological surveiallance app
We are developing an epidemiological app called EpiReportR to help to improve the efficiacy and efficiency of door to door surveillance for the bug species Triatoma infestans, the vector of Chagas disease, which infests human homes in the city of Arequipa, Peru. EpiReportR provides neighborhood maps in which each house appears as a point that is colored according to its relative risk of infestation with the T. infestans. Health inspectors can click on the house they want to inspect and then a form appears in which they can enter the data for that house during inspection, which eliminates the step of digitizing paper report forms.  Maps are updated in real time based on field results. EpiReportR also provides a number of other capabilities for spatial epidemiology work, including access to predictive spatial models, analytic capabilities, and visualization. The cost and expertise required for EpiReportR are minimal, and modification of the app requires only knowledge of R and SQL. The app is fully-functional across computers and mobile devices, open source, and can be easily adapted to a variety of epidemiological missions. The app is currently being tested in the field in various parts of Arequipa.

Investigating human search strategies for triatomine bugs in homes in Arequipa Peru in the context of prior risk information

As part of the public health campaign to interrupt the vector-borne transmission of Chagas disease in Arequipa, Peru, health inspectors carry out door to door entomological surveillance for the triatomine bug species, Triatoma infestans, the vector of Chagas disease in the region.

The selection of homes to inspect is currently carried out randomly, using no historical epidemiological information about a given area to guide their searches. Therefore, we want to know what would happen if we present health workers with a map displaying infestation risk information for every house in a given area. Will they incorporate the information into their select of houses to visit or will they go on selecting houses at randm? And, how does their house selection change when an incentive scheme is introduced for finding bugs? We hypothesize that with the introduction of incentives, health inspectors will be more inclined to incorporate prior risk information into their decisions of which houses to inspect in a given area.

To test our hypothesis, we are developing an experiment in which health workers will be given maps that display prior risk information about bug infestation for each house. We will use GPS tracking to observe how the health workers use risk information to select houses and how their search strategies change when different incentive structures are introduced.Results to come soon!
 
Barriers to participation in public health campaigns
Recently, the vector control campaign in Arequipa has suffered from declining rates of participation, threatening efforts to eliminate vector-borne Chagas disease. In collaboration with the Peruvian Ministry of Health, we investigated the barriers to increasing household participation in campaign efforts, and explored different methods of increasing participation based on a behavioral economics model.
In the first step, we carried out focus groups to discuss with residents what their main barriers to participation were. The results from this work are detailed here.

How urban structures shape canine rabies transmission patterns

Bed bug life history when infected with Trypanosoma cruzi
Can bed bugs and kissing bugs co-exist?

Chagas disease in the Caribbean

In collaboration with researchers from Princeton,  the University of the West Indies, and St George’s University, we carried out a preliminary survey on triatomine bug prevalence in northern Trinidad. Results to come soon!

Chagas disease on a continental scale

In Collaboration with the Pan American Health Organization, Princeton University and Imperial University, we are using Mathematical models to get a more comprehensive understanding of Chagas disease burden on a continental scale across Latin America. This project is in preliminary stages.

Prior Research

Mathematical models of Chagas disease

As a Postdoctoral Researcher in the Dobson group in the department of Ecology and Evolutionary Biology at Princeton University,  I worked to develop mathematical models of Trypanosoma cruzi (etiological agent of Chagas disease) transmission as part of the NTD Modelling Consortium, funded by the Bill & Melinda Gates Foundation. The aim of this project was to use quantitative analysis to assist the World Health Organization in meeting their 2020 goals for Chagas disease.

In this work, we used a mathematical model to explore how animals that live around people (such as pets, livestock, and vermin) can increase or decrease transmission of T. cruzi to the people they live around. We found that  animals slighty increase the speed of transmission to humans, but that transmission is still maintained in the absence of animals, albeit just a bit slower. For example, in a scenario with animals, nearby humans may get infected within 5 years, as opposed to 7 years without animals. This is important, as some have suggested reducing animals as a way to reduce transmission. Based on our work, we disagree with this strategy, as animals affect just the speed of transmission, but not the ocurrence of transmission. To learn more, click here.

Do vectors get sick too?

My doctoral thesis was centered on how human pathogens affect their insect vectors. Every interaction between species occurs in a heterogeneous environment that presents countless contexts that shape the interaction over time and space. The consequences of these interactions can regulate populations, as they trickle down to influence the genes that an individual passes on to its offspring, and then, in turn, scale back up to influence the genetic and phenotypic composition of future populations. In my doctoral thesis, I sought to uncover how these principles play out in the interactions between an invertebrate vector of human disease and the disease agent it carries. Disease vectors are often considered in a context that is faithful to the word as it is used in physics, where the vector is viewed as public transportation that moves the pathogen between hosts, experiencing no consequences of parasite infection. However, vectors face the challenge of how to maximize individual fitness in a stochastic environment with limited resources just as all other species do, so why would they be exempt from the effects of being parasitized?

As such, I investigated the triatomine bug species Rhodnius prolixus when infected with the parasite Trypanosoma cruzi (etiological agent of Chagas disease), and co-infected with T. cruzi and its sister species, T. rangeli. I asked, does T. cruzi affect R. prolixus fitness, and under what contexts does this effect vary? I found a large range of variation in R. prolixus fitness when infected with T. cruzi, with the outcome being influenced by parasite strain, co-infection with T. rangeli, parasite dose, and the timing and order of infection. These factors did not act alone, but seemed to be dependent on one another: it was better to have a co-infection at lower T. rangeli doses, but at high T. rangeli doses, it was better to be infected with T. cruzi first, suggesting an interaction between dose, order and timing. These results illustrate the interactions across scales of both biological and spatio-temporal complexity that can be revealed when studying infectious disease through an ecological lens. Moreover, this work emphasizes the importance of taking into account the ecology of vector-borne neglected tropical diseases such as Chagas disease.

 

Student mentorships

2015-2016:

Alexandra Eakes, Adriana Stephenson and Kathleen Mulligan: Princeton Undergraduate Senior Thesis

2014-2015:
Roberta Hutton,  Princeton Undergraduate Senior Thesis
“Vector control and health care-seeking behavior: Chagas disease and dengue fever in Medellín, Colombia”

In this project, Roberta asked, what are the main factors influencing one’s decision to seek medical care after presenting symptoms of dengue fever or Chagas disease?  We assembled a small team that includes Roberta, Hannelore MacDonald, a local undergraduate student with the University of Antioquia and myself to give out short surveys aimed to measure levels of knowledge of vectors and the diseases they carry, and perceptions about seeking medical care. We also collected background information on each survey respondent to potentially identify associations between age, sex, education, or socioeconomic status with health care seeking behavior. We found that barriers to health care and knowledge gaps in disease knowledge are significantly impacted by socio-economic status.This emphasizes the importance of improving public health measures and exemplifies how poverty can sustain the transmission of vector borne tropical diseases and limit their treatment.

Anchal Padukone, Princeton Undergraduate Senior Thesis
“Relationships between Microhabitat Characteristics and the Abundance of a Chagas Disease Vector, Rhodnius pallescens, in Central Panama”

Thomas Yetter, Princeton Undergraduate Senior Thesis
“Attraction of Chagas disease vector Rhodnius pallescens to artificial light sources”

Hannelore MacDonald: Columbia University, Mailman School of Public Health Masters Thesis
“The role of non-human reservoirs in sustaining T. cruzi transmission across different transmission scenarios.”

2013-2014: Ryan Elliott, Princeton Undergraduate Senior Thesis

“Triatomines and trypanosomes: Fitness impacts of Trypanosoma cruzi and Trypanosoma rangeli mono- and coinfections in the triatomine vector Rhodnius prolixus.”
*Won the department prize for best laboratory thesis poster.

Ryan has now just finished a year as a Princeton Fellow in Africa, working in the public health sector in Lisotho.

2012-2013: Lauren Castro, Princeton Undergraduate Senior Thesis

Flight performance and trypanosome infection of the Chagas disease vector Rhodnius Pallescens: implications for the spatio-temporal spread of Trypanosoma cruzi in rural landscapes.”
*A part of this thesis was turned into a paper and published in the Journal of Medical Entomology (see reference above under Castro et al.)

Lauren is now a graduate student in the Meyers Lab at the University of Texas at Austin working on disease modelling.

Let’s collaborate!

I am always looking to form new collaborations. If have an idea for something you’d like to work on together, please write to me at jenni.peterson@gmail.com.