One of the top “unsolved problems” in biology is the need to untangle complex networks of species interactions - perhaps nowhere is this more consequential than our need to grapple with the socioecological risks of neglected tropical diseases. Human-livestock-wildlife parasite transmission has been declared a major biomedical challenge for the 21st century with reasons for concern that include the potential for zoonotic helminths—parasitic worms such as nematodes (roundworms), cestodes (tapeworms), and trematodes (flukes) to be transmitted between humans and animals. The effects cause malnutrition, developmental delays, and deaths that disproportionately affect communities undergoing rapid development.

A critical problem is that our strategies to identify and track wildlife parasites originated to combat livestock diseases a century ago. We know very little about how to answer the question: What parasites infect tropical wildlife? We know far more about the subset of parasites that harm humans and livestock than all others. Consequently, our conservation partners struggle to identify the parasites they encounter, hindering our collective efforts to rehabilitate endangered species, evaluate emerging health threats, and treat diseases.

Fortunately, we have just received a Catalyst award from the Institute at Brown for Environment and Society to pursue new strategies. Today, the gold-standard method for studying gastrointestinal helminth parasites in wildlife is rooted in taxonomy. Identifying parasites and evaluating their potential to harm hosts requires us to inspect adult parasites from dead hosts. Of course dead-but-well-preserved wildlife are hard to find, especially in the tropics. As a result, we often rely on less-suitable counts of parasite eggs in fecal samples, which can reveal parasites are present but often precludes identification or comparison across studies. This award will allow us to build on recent work at Brown University, which has brought us tantalizingly close to sparking a new era of genome-enabled parasitology that could overcome these intersecting challenges.

Together with an exciting array of partners - Sloth Conservation Foundation (Costa Rica), The Organization for Tropical Studies (Costa Rica), Fundación Zoológica de Cali (Colombia), and the Instituto de Biología Subtropical (Argentina) - we are embarking on an ambitious plan to document and DNA barcode parasites from tropical wildlife across the Americas.  We are also expanding our work at Brown, tapping into the expertise of tapping into the GeoSpatial expertise of Professor of the Practice Seda Şalap-Ayça and Data Scientist Tim Divoll to build more user-friendly and informative data portals. 

​We are grateful for the new support to build and share this important resource!

Out this month in PeerJ, a paper led by Ezequiel Vanderhoeven on "Host specificity of gastrointestinal parasites in free-ranging sloths from Costa Rica."

This paper is the first to compare compare the parasites of wild two- and three-toed sloths across both primary forests and urban habitats. In partnership with our friends at Sloth Conservation Foundation and their detection dog, our team went searching for sloth latrines at La Selva Biological Station and Puerto Viejo de Talamanca. 

We found a bunch of potentially new parasites for both species. Indeed, we found eight types of parasites from just 38 fecal samples, which we were surprised to discover matches the total number of  parasite types reported in the literature for sloths over the last 100 years.

We also found zero evidence for parasite sharing between two- and three-toed sloths, even though they often overlap at very fine scales in their habitats and share so many interesting characteristics. The more common types of parasites we found in each species were present in multiple populations -- suggesting they are widespread within their hosts -- but rare parasites tended to be restricted to hosts from the primary forest. 

This is just the beginning of our work with sloths and their parasites -- a fun, interesting, and important step we are taking together with our partners at Sloth Conservation Foundation. You can check SloCo's blog about it here!

Congratulations to Maddy for being one of only two undergraduates to be recognized with a prestigious Caleel '87 Memorial Undergraduate Biology Research Fellowship from the Division of Biology and Medicine at Brown in 2023! To prepare for her senior thesis next year, Maddy plans to spend the summer studying the health and nutrition of sloths in Costa Rica where she'll be based at La Selva. Exciting work will come from this incredible opportunity ahead!

It was an honor to join this year's OTS (Organization for Tropical Studies) Graduate Field Ecology course last week at La Selva. This is a premier program in tropical ecology, and the course revolves around a series of short (~3 day) research projects led by students and faculty. 

Days of rain made it difficult to do much research in the forest, but there was no shortage of plants and wildlife to learn about at the station. You should read the course's blog to learn more about what everyone was up to.

Carissa Ganong and Andrew Mehring made an outstanding team of lead faculty - it was a thrill to join them!