How a Passion for Parasites is Making People’s Lives Better

An interview with Dr. Ana Sanchez by CNNTD’s SYP Ambassador Maëla Séguin

Maëla: Hello. My name is Maëla Séguin and I am the Students and Young Professionals ambassador for the Canadian Network for Neglected Tropical Diseases. And today I am joined by Dr. Ana Sanchez, who is a professor at Brock University in Ontario. And we are here to discuss her work with neglected tropical diseases, and more specifically, taeniasis and cysticercosis. So thank you very much, Dr. Sanchez, for being with me today. And so first, can you please introduce yourself and discuss your background leading up to your current role as a professor with Brock.

Dr. Ana Sanchez: Ah, certainly. First of all, thank you for the invitation and for your work with NTDs. And I’m always happy to help raise awareness about these important diseases that are so prevalent worldwide. My name is Ana Sanchez, as you mentioned, and I am a professor at Brock University. I’ve worked at Brock University for a little more than 20 years now. And this is my second professional life. My first life in this profession was in Honduras, where I’m originally from, and where I used to work in the National autonomous university [of Honduras] as well. And so tapeworms were the topic of both my masters and my PhD, and then soon after, life brought me to Canada soon after I finished my PhD. But my passion for global health and parasites just grew stronger. And at Brock I’ve been championing the interest in the investment on NTDs.

Maëla: And can you describe your current work?

Dr. Ana Sanchez: Ah, sure. It has been varied because trying to adapt to a Canadian interest, Canadian students’ interests; the beginning was more trying to–perhaps do what was more relevant here because the country wasn’t ready. There was no such NTD network. There was not a lot of awareness, and it was very hard to get grants. I was able to get grants from the CIHR and later on from the consortium of grants to do work on–not just infectious and neglected tropical diseases– but also in capacity building.

Maëla: And so in your work with [parasitic] diseases; infections, you’ve also worked with neglected tropical diseases such as taeniasis and cysticercosis. So can you explain to us what taeniasis and cysticercosis are?

Dr. Ana Sanchez: Yeah. Well, this is one interesting parasite. It’s called Taenia solium and it is a tapeworm. The interesting part is that it took researchers and clinicians a long time to discover that the two stages of these parasites were [one and the same] one in pigs in their meat where they see the larval [stages], that receives different names depending on the country. But we know that they are cysts—they are called cysts; that’s why it’s ‘cysticercus’–they look like a little pomegranate seed. If you can imagine that inserted in the meat of pork; of pigs, right? So this exists in pork-eating countries, particularly countries where it is a very informal economy. So it’s not like an industrialized big farm; it’s like a backyard. The family has two, three pigs. They have to fend for themselves, and then they scavenge for food and then they contaminate themselves with human feces. And then this is one side of the parasite. The other one is the tapeworm, which is the long four-meter-long tapeworm. It’s called tapeworm because it looks like a wide tape; really long and flat. It can accommodate itself in our intestines. People acquire that tapeworm by eating the pork meat that is not properly cooked. And that little pomegranate seed contains that little head that once inside your gut, is gonna grow, and in three months, it’s gonna measure four, five meters long. Incredibly, it doesn’t cause a lot of symptoms because it’s very quiet. It’s very thin and it’s just there quietly absorbing your nutrients, and it can live for years in that person without treatment. Now that is the natural cycle. So in the pork, in the pig, it’s called cysticercosis, or more technically porcine cysticercosis. And it can go anywhere in the pig, but for particular reasons for transmission, we’re interested more in the skeletal muscles. It can go in the eyes or in the brain as well. But normally those are not eaten by humans. And the taeniasis is the human harboring that tapeworm. And the human is just like a carrier of that tapeworm: nurtures it, gives it food, gives it shelter, and it’s a true parasite. The tapeworm is there just using us and then shedding in the person’s stools those infectious eggs.

Now in the human–although we mentioned that in the pig, it goes mostly, or we are interested mostly in their muscles–in humans, there’s a particular attraction for the central nervous system. So this little pomegranate seed will get seated in the spine–anywhere in the spine–the ventricles or brain parenchyma; so anywhere in the central nervous system, not just in the brain: sometimes in the eyes as well, because they’re part of the central nervous system. They may go to the muscles. They may go under the skin, but those cases are not as obviously clinically dangerous. But if you have a parasite of five millimeters big, and then it’s in your eye or in your brain parenchyma, or obstructing one of the ventricles, this is when neurocysticercosis, the neurological infection of this tapeworm in the human–then that’s when we have the problem. And just to give you a couple of signs and symptoms, the most common would be, late onset epilepsy.

You can treat people with the tapeworm for sure. And the treatment is effective. You can eradicate the tapeworm from the intestines, but it’s very hard to find those people. If you only have two people among 500, you really have to look at all of them, you know, and do stool samples or antigen samples or DNA, whatever; you have to go to the community. It’s just very hard to find. With people with neurocysticercosis, the problem is that the parasite may be quietly living inside your brain, for example, for years, without people knowing and once you start to get symptoms, a lot of the time it’s because the parasite starts dying and it causes like an inflammatory reaction around it. And when it dies, it leaves a scar and a lesion in your brain parenchyma. And that’s never gonna disappear. So [the patient] is going to have epilepsy for the rest of their lives, even though the parasite is dead already.

In very few cases, you can catch the cysticerca in the brain [that are] still viable, and they are susceptible to treatment. You can treat them with antiparasitic drugs under medical supervision, normally hospitalized because of the reaction that it may cause by killing all these parasites at the same time. But it has treatment. It’s just that most of the time it’s too late and you have to treat the consequences of [the infection]; which is long term.

Maëla: Now, some of your other professional interests include research partnerships and capacity building. So could you explain to us what a fair and equitable research partnership looks like to you and why it’s important, and the impact in NTD research and advocacy?

Dr. Ana Sanchez: Yeah, I am that person from a low/middle income country, right, that gets approached by other researchers from Europe or North America. And it’s very common and I’ve experienced myself the lack of principles for global health research. And one thing for me it’s important that the partnership has to have–I don’t know if you probably are aware of the CCGHR principles, you know, where you have respect for the other partner. And we both together, we build the research agenda and we both are responsible for the things that we do, but everybody offers the best of their talent. So, I think that giving recognition to the partners, discussing things together, respecting cultural differences, to be sensitive to differences and power imbalances [are important].

Maëla: My final question for you, Dr. Sanchez is, as a professor at Brock University, you must work with students and young professionals with NTDs. And so, what are some ways in which you’ve been able to engage, youth, young students, and professionals in the world of NTDs and why is it important to engage youth in the fight against NTDs?

Dr. Ana Sanchez: Oh, absolutely. Well, first of all, the courses that I teach–medical microbiology, global issues in infectious diseases, and tropical parasitology–particularly the last one, they all touch on NTDs. And most of the time students are like, ‘Oh, I didn’t know that. I didn’t know that this parasite existed, that affects your heart’. There you go–or your eyes and causes blindness. So it’s super important to build in a proper scientific knowledge in the courses and in the labs. That’s one way. The other way is supporting, like say, the Canadian Association for Global Health–has chapters in every university and they are normally undergrads. So, I am their mentor, and I help them. This group is just getting started, but we have put together events for the sustainable development goals and, or for food security or, snake bites, which is another of the NTDs–even more neglected than NTDs because the anti-venoms (antidotes) are–it’s very rare to find. And a lot of people die of snake bites just because they are too far away from the next clinic with an antidote. So, we have showed movies and we even have snakes coming to Brock, you know, to raise awareness. So, we do a lot of stuff in terms of education. My grad students work on that. And once they go and they continue their lives, if they become a physician–many of them study medicine–they will be more aware. I used to bring–I brought five groups, almost a little more than a hundred Brock students, two hundred grads–with me in a global health field course, and it was amazing. I only stopped because there was a coup d’état the last time we were there and it became a bit dangerous. I normally now bring my grad students only, two or three, and we have more control. But all of these people that have benefited from my courses from going in the field course from undergrads, to even directing readings…and hopefully growing and move away from that, you know, ‘Eeek’ factor that many people in high income countries have. When you say parasites, when you say worms and you say lice, you know, there’s this factor, almost stigmatizing of the kind of research that you do… But if they knew the importance, you know, and actually improving people’s lives. So, I think we need to understand that, because there’s a lot of humanity in the work of NTD as well. You have to have that humanity, and I think that makes better people. So I’m very proud of many, many, many Canadian students that have gone into this journey with me at the beginning with a little bit of ‘Eew’ and then at the end, it’s like, ‘Oh my God, I love this. I never knew it was possible!’ So they just have to pass that moment where they’re like, ‘Oh, I don’t think I can do this’ and there you go. They end up in Liverpool, you know, tropical medicine or, or in Sweden or in Colombia. It doesn’t matter, but they’re taking it with them. So it’s quite rewarding.

Maëla: Exactly. Well, thank you very much, Dr. Sanchez. This concludes our interview. So, thank you for your time, and on behalf of the Canadian Network for Neglected Tropical Diseases, I would like to thank you for all of your efforts in the fight against NTDs. And, this was a pleasure to be able to host this interview with you. So, thank you once again, and I wish you all the best in your future work

Dr. Ana Sanchez: Well, thank you so much Maëla. And thank you for your work and for the NTD network work as well. It’s marvelous that it does exist. I am very proud to say that in Canada, there’s an NTD network, and people are like ‘In Canada, really? It’s not too cold?’. But hopefully we get more and more interest, and more researchers that can take the torch with them and let’s keep making people’s lives better. So thank you for the invite. And it was an absolute pleasure. Thank you.