Securing parasitic egg samples in San Francisco

Sometimes the most extraordinary samples come from the most unexpected connections. Through a friend of a friend, we found the lab of Dr. Brian Graham at UCSF — who handed our team one of the stranger gifts in global health research: a vial of Schistosoma haematobium eggs.

This is the story of the S. haematobium eggs we collected at UCSF, carried to another Bay Area lab, and brought all the way back to Houston — and what we plan to do with them. Because they’re killed eggs, they let us study the precise evidence of infection safely, with no risk of live infection and none of the upkeep of a live animal model. That single sample moves us toward our larger goal: accessible diagnostics for rural communities, validated against the exact specimen our tools — like the Foldscope — need to be ready to detect.

For the unfamiliar, S. haematobium is the parasite behind schistosomiasis — also called snail fever, or bilharzia. Its eggs are normally only encountered in clinical samples from infected patients, which makes them critical for diagnostic development yet difficult to obtain in a controlled laboratory setting. Our vial has since been divided into aliquots bound for two research hubs: the Prakash Lab at Stanford’s Shriram Center for Bioengineering, and Dr. Lee’s lab at UTHealth in Houston.

A friend who connected the dots

Maya Grayck — my dear friend and coworker in Clyde Wright’s lab at CU Anschutz from 2021 to 2023 — joined our team and this project in March. We’re glad to have her for many reasons, but one stands out: without her knack for connecting dots across states, institutions, and labs, we simply would not have access to these samples.

In March, Maya got up to speed on a Zoom call with Jim Cybulski, Manu Prakash, and the Health in Your Hands team — and within a few days she realized our worlds overlapped in an unexpected way. Her mother, Dr. Eva Nozik — mentor and friend to so many — had just studied pulmonary hypertension from chronic schistosomiasis in a murine model, alongside Brian Graham, who keeps schisto specimens in his lab at UCSF.

Eva is the kind of physician-scientist who studies — at the highest level — just about every nuance of an organ system, so I should have known we’d be seeking her sage advice eventually, given schistosomiasis can reach the lungs: her area of expertise. At that point, I was still naive to that clinical consequence.

Why these eggs, specifically?

A fair question we kept getting: why not just use the eggs already in Dr. Lee’s lab — aren’t those good enough? Both S. mansoni and S. haematobium are parasitic flatworms that cause schistosomiasis, but they differ in where they settle in the body, what their eggs look like, and how the disease presents.

This distinction is critical for diagnostic development. Urine-based diagnostics — especially the low-cost, field-deployable kind we’re building — must be tested using S. haematobium eggs specifically, since they differ in size, shape, and localization from S. mansoni eggs.

A tiny rented car, a big errand

In early April, Maya joined myself, Phillip, and Nehali on a trip to Stanford. Anesta Kothari and Hope Leng — who are working on a low-cost molecular test for schistosomiasis — coached us on how to ask for the eggs and how to transport them. We opted for frozen samples on dry ice.

A couple of days in — realizing time was running short — I asked Phillip and Maya whether they’d take our tiny rented car and run the mission to UCSF without me, while I stayed on campus, another coffee in hand, prototyping and testing the microfluidic trap we were developing. They accepted the mission.

What we’ll do with them

Here’s the mile-high view of what our Stanford collaborators and friends plan to use the samples for — three reasons these specific eggs matter to the work ahead.

We’ve joined forces with Vaibhav Shokeen for the current study, and we’re thrilled to be meeting in five weeks in Nigeria. In the next lab note, you’ll see how we use these samples to help train his automated model. More to come — stay tuned, my friends.