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Grantee Insights: ‘Why Fruit Bats? Why Not?’

It is high summer in Madagascar and the sun beats down relentlessly on our dusty field camp. I huddle beneath an invasive pine tree in this impacted landscape, trying to protect my laptop from the bright glare of the masoandro — the “eye of the day,” as the Malagasy call their sun. “Mamay ny andro,” says...

It is high summer in Madagascar and the sun beats down relentlessly on our dusty field camp. I huddle beneath an invasive pine tree in this impacted landscape, trying to protect my laptop from the bright glare of the masoandro — the “eye of the day,” as the Malagasy call their sun.

“Mamay ny andro,” says my coworker, Ando Rabemiafara. It burns today.

I nod in agreement, wiping my sweaty hands on my shorts before returning my attention to last night’s netting data, which I type into an Excel spreadsheet. I marvel that these 2018 entries follow upon those most recently entered in January 2016. I am faintly horrified to admit that it has been two full years since I last held a fruit bat — though in my defense, I spent those last two years earning my PhD.

National Geographic Explorer Cara Brook pulls a Pteropus rufus fruit bat from the net. Ambakoana, Madagascar, February 2018. Photo by Christian Ranaivoson.

In 2016, I wrote to you as a doctoral student at Princeton University, where I studied the infection dynamics of potentially zoonotic (or human-infecting) fruit bats in Madagascar. Bats have received much attention in recent years for their role as natural reservoir species for several emerging viral infections in humans, including Ebola and Marburg filoviruses, Hendra and Nipah henipaviruses, and SARS coronavirus. The unique island ecosystem of Madagascar is home to three endemic fruit bat species (found nowhere else in the world), and each boasts a lineage previously implicated in a major viral zoonosis: the genus Eidolon with Ebola, the genus Rousettus with Marburg, and the genus Pteropus with Hendra and Nipah viruses. In Madagascar, all three fruit bats are widely consumed by humans as food.

Now a postdoctoral fellow with the Miller Institute at UC Berkeley, I am building on my dissertation work to investigate seasonal drivers of viral transmission in these bats under an NIH-funded research initiative, led by Dr. Jean-Michel Héraud, head of the Virology Unit at the Institut Pasteur de Madagascar (IPM). My trusty research partner, Christian Ranaivoson, now a doctor himself, is ever by my side — a new postdoc on our grant — in addition to a IPM-based laboratory postdoc, Dr. Vololoniaina Raharinosy.

Previous work has demonstrated a distinctive seasonality in spillover events of most bat-borne viruses to humans, or other secondary animal hosts (i.e. pigs, horses, and civets — respectively implicated in cross-species transmission of Nipah, Hendra, and SARS). Typically, this seasonality has been linked to wet-dry season transitions and the yearly birth pulse of the bat species in question. My dissertation work highlights similar seasonality in immune signatures of filo and henipavirus exposure in our Malagasy fruit bats. As a postdoc, I am keen to build a more finescale longitudinal dataset to help differentiate between several existing hypotheses of the mechanistic drivers underlying this pattern.

Baby Nicolas watches the bat team. Angavokely, Madagascar, February 2018. Photo by Cara Brook.

I’ve spent the past two years building laboratory and modeling skills to help me make the most of our Madagascar field data, but I admit that, at times, it has felt like I have lost touch with my roots. A year ago, while teaching a quantitative data analysis workshop to Malagasy students, I surprised an observer by claiming my identity as a field biologist. “I thought you were a mathematician!” she exclaimed, choosing a title I would have never envisioned for myself. As Yun-Yun Li, an undergraduate research assistant from my dissertation days, once wisely noted, “I think you are still trying to decide what kind of scientist you want to be.”

After two years away, it’s refreshing to revisit our age-old field sites but a little bit sad, as well. I’ve seen much of Christian in the intervening time, but for many of the local community members in the regions where we work, it has been two years since I have seen fit to mandalo — to stop by. In that time, the cast of characters has not much changed: there’s Zervé, the landowner, his sweet wife Lalao, and their cute son, Tojo, whose cuteness has now been eclipsed by that of a baby brother, Nicolas. And there is our longtime coworker, Ando — once bat hunter, now simply net-maker — and Rabesty’fanihy, father of the bats, who has never told me his real name. Rabetsy has been independently monitoring the local Pteropus rufus roost for no gain beyond personal interest since funding for a former conservation project dried up back in 2007.

Rabetsy, Ando and Zervé all still cycle through the same handful of T-shirts I knew them in last, though their hems are much more ragged and their faces much more tired than I remember. Ando has lost his four front teeth to a taxi-brousse accident.

“I guess I’m still wearing the same clothes, too,” I say to Christian, glancing down at the tattered boys overshirt and threadbare soccer shorts in which I’ve been so professionally cavorting around Madagascar for the past five years.

“True,” says Christian, “though for you, it is a choice.”

Ekipa Fanihy, the ‘Bat Team.’ Ambakoana, Madagascar, February 2018. From left, Ando Rabemiafara, Christian Ranaivoson, Rabetsy Fanihy, Angelo Andrianiaina, Hary (Madama Rabetsy) and Cara Brook. Photo by Jules Rakotonirina.

The skills and pace of field life come back to Christian and me quickly, for we were both born for this work. But I have mellowed with age and experience, and the worries that consumed me as a PhD student seem somewhat trivial now. In a previous life, I used to insist that we split all the field tasks as we processed and released each captured bat. But I no longer care so much that Christian is better at drawing blood than me; in fact, I’m happy — and proud — to let him collect us better data. Likewise, I used to be saro-piaro — jealous, in the possessive sense — about being the one to pack our field materials up in their respective boxes. These days, it occurs to me that it maybe does not matter that the eager new PhD student, Angelo Andrianiaiana, puts the calipers in a different box than I would have chosen. I guess wisdom and perspective improve with time and I am preparing myself to become obsolete to my own work.

Under our new NIH grant, we’ll be sampling these bat roosts monthly for the next five years — news that makes Rabetsy leap to his feet and actually kiss my cheek in gratitude. But I won’t be here all 12 months of every year. As Yun-Yun said so wisely, I’m trying to be many kinds of scientist all at once, and there are skills to learn and resources to exploit back in Berkeley, too. Still, I feel guilty — both to leave and to stay. But when I confess my anxiety to Christian, he just smiles and assures me, with his characteristic calmness, “You are doing the best you can.”

I remember a lecture I attended back in graduate school, in which University of Pennsylvania Professor Daniel Janzen, described his celebrated conservation and development project in Guanacaste, Costa Rica. Janzen has been employing dozens of local community members in conservation-based caterpillar research for much of the past 35 years. When asked, “Why caterpillars?” Janzen’s reply, was simply, “Why not?” In his opinion, the development consequences of his work alone fully justify the science.

As a scientist, I have no doubt that I’ll be chasing answers to my thrilling research questions for a lifetime. But as a human, I vow, that should there someday come a time when I am no longer excited about my work, I need only remember Rabetsy’s face upon hearing of our grant success and dig deep within myself to ask, “Why fruit bats? Why not?”



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Meet the Author

Cara Brook
My name is Cara Brook, and I am a postdoctoral fellow with the Miller Institute for Basic Research at UC Berkeley. I study the role of bats as reservoirs for some of the world's most deadly emerging viruses, including Ebola and Marburg filoviruses, Hendra and Nipah henipaviruses, and SARS coronavirus. I bridge field ecology, cellular immunology, and quantitative epidemiology to investigate this question, at both within-host and population levels. I blog from my field site while tracking down fruit bat viruses in central Madagascar. Tonga soa --Cara E. Brook is the recipient of two research grants from the Nation al Geographic Society.