Quantifying the relationship between human mobility and disease transmission is critical for identifying disease sources and designing interventions. Methods for capturing mobility patterns have largely been used to characterize settled populations. Mobility patterns in mobile populations, such as nomads, are less well known. These populations may be at higher risk of acquiring new infections or may import/transmit new infections as they move. Characterizing their mobility and disease exposure rates is crucial to understanding their role in disease transmission.
Dr. Hannah Meredith was awarded a Fogarty International Fellowship to expand upon our group’s work with the Turkana, a semi-nomadic population, to test the hypothesis that the Turkana are at greater risk of exposure to vector-borne diseases during seasonal treks than when staying at their semi-permanent settlements. For the last year, Dr. Meredith has lived in Kenya, working with community health workers in Turkana to enroll semi-nomadic households in the study, screen them for malaria before and after their seasonal treks, and assign GPS loggers to migrating pastoralists to collect information on their migration routes. Analysis is ongoing, but preliminary results of malaria prevalence in the community further demonstrates the need for interventions that are more suitable for mobile, outdoor dwelling populations.
Dr. Meredith (3rd from right), Dr. Andrew Obala (2nd from right), and research assistant Dennis Okoth (far right) stand with community health workers from Nakurio and Louwae to commemorate the closing of the study at this particular site.
Households typically build structures out of sticks and palm fronds (right) surrounded by a fence to keep livestock corralled at night. These structures are quick to build (a few days) and are usually built to store belongings and provide some shelter from the elements; however, many household members sleep outside. On the left are a set of 4 sticks that were sometimes used to suspend a bednet over the sleeping area; however, few households reported having access to bednets.
Most semi-nomadic households owned camels, sheep, and/or goats.
Drs. Obala, O’Meara, and Meredith on a site visit in Turkana
Meet Christine Markwalter! She is one of the postdocs working with the O’Meara Lab and has been a member of the greater malaria research community at Duke for 3 years. Christine came to Duke after completing her doctoral studies at Vanderbilt University in chemistry. She is currently focused on a project analyzing haplotypes from mosquitos and humans that are a part of the Once Bitten cohort study, as well as some haplotype data from our Turkana project.
So how did Christine end up studying malaria in Kenya with a PhD in chemistry, you might ask?
Well, by way of bioanalytical chemistry, actually. For her doctoral work, Christine was investigating how to make rapid diagnostic tests (RDTs) more sensitive in order to detect lower density infections, specifically for malaria and schistosomiasis. After she finished her PhD studies in the lab, she decided she wanted to gain more epidemiology and field work experience, which is what ultimately landed her in the Malaria Collaboratory at Duke.
This past summer, Christine was able to spend 3 weeks in Kenya. This was her first trip visiting the field site there, and her trip started off with the ever-eventful loss of luggage by the airline. Normally this wouldn’t have been a huge deal for a seasoned traveler like Christine, but this time she was traveling with her husband Daniel, an Emergency Medicine fellow at UNC, and their baby daughter Ellis. Thankfully they had packed most of baby Ellis’ items in their carry-on’s, but the first day or two in Eldoret were spent going back and forth to the local mall to get spare clothes and supplies.
The ExactDx team, in true harambee fashion, did their best to help Christine and her family settle in sans luggage. On the way from the airport to retrieve their suitcases a few days later, Edna and Julius thought it would be fun to give Christine and Daniel a taste of traditional Kenyan cuisine. They stopped off and treated them to some nyama choma (grilled goat meat) and ugali. The meal remains a favorite from their visit, and Christine and Daniel cannot wait for their next opportunity to enjoy delicious Kenyan cuisine.
After a week of orientation in Eldoret, meeting with different team members in person, including some collaborators at Moi University, Christine and baby Ellis headed out to Webuye to experience a day of “ento.” “Ento” is short for “entomology” and refers to the days when field researchers (FRs) strap on their prokopacks and visit each of the households enrolled in the Once Bitten study to collect mosquitoes. The days begin early, usually around 6 am. This is the optimal time for catching mosquitoes in the households where they have potentially bitten members during the night. Household members are asked to keep windows and doors closed until team members arrive for mosquito collection.
“I was blown away with how generous the study participants are, letting the study team into their homes to collect the mosquitoes so early in the mornings. To me that is typical of the Kenyan hospitality I experienced throughout my trip,” recalled Christine.
Christine enjoyed getting to use the prokopack and helping collect some of the mosquitoes whose bloodmeals she’ll ultimately end up analyzing in the US. She was able to spend the afternoon with the FRs back at PEARL where she observed them sort species, rear, sacrifice and dissect the mosquitoes. The team places the mosquito parts (head, wing, and abdomen) in pre-labeled eppendorf tubes and package them by household and village before shipping them to the Taylor lab in the US. Once in Durham, members of the Taylor lab receive the mosquito parts (heads, wings, and abdomens) and processes the mosquitoes further, extracting and sequencing parasite DNA for analyses. This field visit provided Christine with knowledge and insight about the context and environment from which samples are collected, and will give her a richer understanding as she conducts her analyses and thinks about the team’s scientific questions.
In addition to gaining invaluable field experience, Christine volunteered some of her laboratory expertise at PEARL to help get a mosquito PCR speciation assay up and running. One difference she noticed between the lab set up in rural Webuye compared to Durham was the impressive amount of planning and forethought required to keep things running smoothly in the lab. At Duke, if a reagent runs out or if she runs into a problem with an instrument, she can just make an online order for next day delivery or take advantage of the many resources and experts available on campus. When challenges arise in the lab in Webuye, the team approaches them with creativity and careful planning, keeping a detailed inventory log so that orders can be placed months in advance. Christine was impressed by the molecular assays and techniques the PEARL team performs, and she is excited by the lab’s potential to do more as the program continues to grow there.
Christine leads a CME course via Zoom.
Christine also facilitated the monthly CME course for July, which is part of the many training activities that are conducted out of PEARL. Her topic was diagnostic technologies and she went over the advantages/disadvantages of different formats (rapid tests, PCR, antibody detection, etc.). The topic was very timely given the recent discussion globally around COVID-19 diagnostic methods and was attended by clinicians and researchers at PEARL and virtually.
She wrapped up her trip in Eldoret working with some other expat collaborators who were fortuitously visiting our office at the same time (a rarity during pandemic times!). She and her family are so grateful to have met the ExactDx team in person and for their genuine hospitality and care. They are already looking forward to returning! Karibu!
“My brother thought I’d like to code but I didn’t want to listen to him,” says Zena Lapp, our newest computational postdoctoral research associate. Famous last words!
Zena joins us from the University of Michigan where she finished up her studies in Bioinformatics and Statistics. Even though she just got to Durham this past August, it seems like she’s been a part of the team for ages. She jumped right into the Once Bitten project and has started sharing some of her initial analyses at group meetings. Listening to her present her colorful, well-thought out figures, you would never guess that she didn’t always know that she wanted to pursue a career in malaria genomics research.
Zena grew up in Pittsburgh. Her father was a doctor and throughout her childhood, her entire family packed their bags and accompanied him on medical trips to South and Central America. These experiences were incredibly formative for Zena, whose family members all speak Spanish to varying degrees as a result. So it was only natural when she graduated from undergrad that she decided to take a gap year in Bolivia working with Nuestros Pequeños Hermanos, the same organization her father had volunteered for. As is requisite while taking a gap year, Zena was using the year to think about what she wanted to do for the rest of her life. In the meantime, she was volunteering at a children’s home, coordinating volunteers and managing the organization’s donation website. But as the year went on, she felt like she needed a little more intellectual stimulation. It was then that she realized that maybe she should have listened to her little brother’s advice after all.
“I had a computer and internet access.” And so, she started to teach herself how to code.
She started learning Python with Codecademy. Upon her return to the US, she sat in on some computational biology and bioinformatics classes at the University of Pittsburgh. It was then that she found her calling! She combined her undergrad experience in biochemistry and molecular biology and coding, and decided to apply to PhD programs in bioinformatics. She never lost her passion for global health, and after completing her PhD where she worked in an infectious disease lab, she decided to pursue a postdoc in global infectious disease epidemiology, focused on using genetics/genomics to study transmission of ID. This ultimately brought her to the Malaria Collaboratory at Duke. But the rest is not history.
While Zena was studying for her PhD at Michigan, she and her friend Brooke Wolford decided to co-found a Girls Who Code chapter. During her undergraduate studies, Zena had avoided programming classes because she just had the idea in her mind that she would hate computers. Now, she was working with young girls to help inspire them to pursue careers in computer science by not only teaching them how to code, but also by exposing them to women working in the field. Every meeting started with a guest speaker who talked about her own career trajectory, many of them Zena’s fellow grad student friends as well as some women working in industry at places like Google. Her favorite part of Girls Who Code was seeing the girls become more confident and excited about their coding skills and projects, and she is super happy to see the next generation of board members continuing to inspire young women to code.
