Study Finds Intestinal Parasites in Mississippi Kids Linked to Poverty
Too often, Americans believe that infections from intestinal parasites happen only in remote rural areas and/or third-world countries. Spotlight has covered the parasitic infections caused by unclean water and raw sewage in rural Alabama in recent years, and recently spoke with Tara Cepon-Robins, associate professor of anthropology at the University of Colorado Colorado Springs about a new study focusing on Mississippi. Cepon-Robins and her team found widespread intestinal parasitic infections among children in a rural Mississippi Delta community as well as elevated intestinal inflammation. The levels of intestinal inflammation in the Mississippi children sampled were 17 times higher than those documented among Indigenous Shuar children from Amazonian Ecuador, a population that experiences stunting associated with high bacterial, viral and parasitic infection loads. The conversation with Cepon-Robins has been lightly edited for length and clarity
Tell us how this study came about—had you done previous work in Mississippi?
Originally, I started my research in parasitology in Amazonian Ecuador. I did my dissertation fieldwork among the Indigenous Shuar. There, we found high rates of intestinal helminths or parasitic worms. As I dug deeper into parasite infection around the world, I came to realize that at least some work was done in the U.S. up until the 1950s through the 1980s. That work showed that people in the U.S. actually had similar parasite infections to what we were finding in Ecuador. But after the 1980s, we just sort of stopped talking about them. We don’t see any more surveys. You see occasional case-based studies and you see occasional immigrant studies looking at parasites in the U.S, but you get very little information on endemic infections within the U.S. We, as a country, just sort of collectively started pretending that parasite infection doesn’t affect us here. So, with that in mind, my colleague Dr. Theresa Gildner and I created the Rural Embodiment and Community Health (REACH) study to dig a little deeper and follow up on the few surveys that had been done recently to see if we could document parasite infections in the U.S. We started looking into areas in the southern U.S. due to similarities with other tropical environments where these neglected parasitic infections often spread; similarities like environment/climate, sanitation challenges, and resource access issues. Luckily, I was put in contact with communities in Mississippi to do this work there.
Tell us more specifically about the study—what you actually did and why.
We were working in the Delta, which is one of the areas that historically was shown to have high parasite infection rates; up to 50% of residents in some counties were infected with soil-transmitted helminths, which are intestinal parasitic worms that are transmitted through fecally contaminated soil. We worked in a small, predominantly Black community that has very limited access to resources—the nearest full grocery store, for instance, is 20 to 30 minutes away, which is kind of insurmountable if you don’t have access to a car. Many community members end up relying on the local Dollar General or gas station for groceries, which severely limits access to healthy foods. This community also experiences frequent flooding and infrastructural neglect that leads to sewage backups. Exposure to raw sewage is a major way that you can spread intestinal parasites. So, this community was a really good one to look into. One of our colleagues had actually done soil samples there and had found evidence of parasites in the soil, so we wanted to follow up to see if people were infected with parasites there as well.
And what is the name of the community?
I can’t disclose the name because this is a relatively small community/participant pool and we are gathering private health information.
Ah, understood. Well, tell me what you found.
Our preliminary field season was in 2019 and we got a sample of 32 kids, 24 of them whom returned stool samples. And we found that about a quarter of them had parasitic worms. With a small random sample taken from a community, that is surprising and supports our idea that parasites may be more common in the U.S. than we think. We did 18 SSRNA sequencing, which allows us to get at lighter infections than just microscopes do, and we were able to get a little bit more specific and found that they were platyhelminths, meaning flat worms. In the U.S., platyhelminth infections tend to come from tape worm, and we found a couple of nematode, or round worm, infections as well. We were just back in the community this past June (2022) and are getting follow up data on adults in the community as well to see if they are also experiencing infections.
Besides evidence of parasite infections, we found something else that is really striking, and I think points to the need for more infrastructural investment, both at the local, state, and national government levels. We found that 80% of kids in the 2019 sample had clinically elevated intestinal inflammation, measured using Fecal Calprotectin. And what I think is really interesting and important about the elevated intestinal inflammation in this sample is that it goes hand in hand with the idea that poverty, marginalization, resource access, all of those experiences can become embodied and can lead to internalized health problems. One of the things that this paper touches on is that Black Americans tend to experience higher rates of certain gastrointestinal cancers and studies have looked at how different populations immunologically respond to infections with bacteria, like H. pylori. These are not genetically determined responses, but likely based on immune priming. What might be occurring here is that the immune response is basically primed by these external experiences, like poverty, experienced and systemic racism, and lack of resources and healthy food access—all of that can contribute to your immune profiles by increases inflammatory responses and altering how you respond to pathogens, which can lead to these higher rates of intestinal inflammation and gastrointestinal issues.
And for the kids in whom you found positive samples, were they all symptomatic?
No, very few reported stomach pain, diarrhea, vomiting, or other gastrointestinal symptoms. We interviewed their parents to get at whether or not they were having any symptoms, and the majority were not.
So, you’re doing follow up with adults—what else are you doing in terms of following up on this work?
We expanded our sample to include both adults and children. We collected more blood samples from minimally invasive finger-pricks so we can start to assess more markers of immune function and immune responses. We also collected stool samples again and are planning to run more in-depth analyses to understand what species of parasites are present in this community. We are also analyzing the microbiota this time, which is the collection of bacteria that live in the intestines to look for evidence of pathogenic species and imbalances that may be contributing to inflammation. Importantly, we are also looking specifically at Helicobacter pylori infection since this is thought to contribute to disparities in inflammation and cancer rates.
And I know you’re confined by privacy issues, but has there been any movement to look at infrastructure changes in this community?
We’ve started a community health panel with local nurses and nurse practitioners to try and see, first of all, what’s important to the community, what sorts of resources are available there currently, and then hopefully that will expand into something bigger with more information for seeking treatment. We also collected environmental samples this year (things like soil from places within the community) so we can figure out where people are likely being exposed to infections. To this end, we also collected lifestyle and household data during interviews in hopes of pinpointing where exposure occurs and who is most at risk. Hopefully, once we have bigger samples, we can have a bigger impact and help to inform and encourage infrastructural investment and change.