Cercopithecus monkeys opportunistically prey on bats

C. mitis, photo Diana Robinson

Two species of Cercopithecus monkeys in Kenya have been observed and documented feeding on bats when the opportunity presents itself. Tapanes and colleagues (2016) photographed and filmed this behavior in Blue monkeys, Cercopithecus mitis, and in one monkey which was a hybrid species of C. mitis and C. ascanius, the Red-tailed monkey. They report on thirteen observations of bat predation attempts over six and a half years at two sites, Gombe in Tanzania and the Kakamega Forest in Kenya). Of these thirteen attempts, eleven were successful. Surveying researchers of blue and red-tailed monkeys at other sites did not identify further instances of bat predation.

Although identifying the bats was challenging, Tapanes and colleagues determined that multiple species of bats were consumed. Researchers observed two instances where an individual grabbed a lone roosting bat and consumed it. In the other observations, the researchers did not witness the individual capturing the bat.

Unsurprisingly, the evidence suggests that bats are a preferred food item for Cercopithecus monkeys. In two of a successful predation event, other monkeys gathered around and observed the monkey feeding on the bat. Three instances were observed where some sort of aggressive display or behavior to either obtain or retain the bat, implying this food item is worth fighting over.

All observed instances of this behavior occurred in either forest edges or human-modified habitat, raising the question as to whether or not this behavior occurs naturally or is a product of habitat destruction and alteration due to human activities. It is possible that anthropogenic changes to the landscape have resulted in blue and red-tailed monkeys altering their feeding patterns and behaviors accordingly, with increased consumption of bats as a potential modification. Thirty-six years of data collection at Kakamega forest show that bat predation coincides with increased use of plantation forests that has occurred due to forest fragmentation and loss. Tapanes and colleagues (2016) also suggest that bat predation could be more widespread, but it is simply easier for researchers to observe this rare behavior within altered habitats. They do not think this reason is likely, stating that observation conditions were similar in both plantation forest and forest that is more natural.

Blue monkey feeding, photo Christoph Strässler

These findings have important implications for the transmission of zoonotic diseases, or diseases that can be transmitted from animals to humans. It has previously been hypothesized that primates contract diseases from bats when they consume fruit with an infected bat's saliva or feces (Dobson, 2005; Alexander et al., 2015; Rodhain, 2015). This latest study forces us to consider the fact that directly handling the bats themselves may be a method for disease transfer. As monkeys can transmit many diseases to humans, it is worth studying this phenomenon more, if possible.

Links of potential interest:
IUCN Redlist page for C. mitis
Primate zoonotic diseases
Which primate is likely the source of the next pandemic?
Ebola, primates, and bushmeat

Works cited:
Alexander, K. A., Sanderson, C. E., Marathe, M., Lewis, B. L., Rivers, C. M., Shaman, J., ... & Eubank, S. (2015). What factors might have led to the emergence of Ebola in West Africa?. PLoS Negl Trop Dis, 9(6), e0003652.
Dobson, A. P. (2005). What links bats to emerging infectious diseases?. Science, 310(5748), 628-629.
Rodhain, F. (2015). Chauves-souris et virus: des relations complexes. Bulletin de la Société de pathologie exotique, 108(4), 272-289.
Tapanes, E., Detwiler, K. M., & Cords, M. (2016). Bat Predation by Cercopithecus Monkeys: Implications for Zoonotic Disease Transmission. EcoHealth, 1-5.

Studying the ecology of disease and primates

We often think of habitat loss, hunting, and perhaps even the pet trade as serious threats to primate conservation. Disease, on the other hand, is commonly forgotten. Yet, increasingly fragmented forests create more opportunities for humans and wildlife to come into contact and potentially transfer and spread disease. Our close genetic relationship with non-human primates further increases the likelihood of spreading illness through contact, making this a topic worth paying attention to.

Cryptosporidium parvum

A study came out recently in the journal PLOS Neglected Tropical Diseases that should remind all of us not to exclude disease as a potential threat to non-human primate conservation. Parsons et al., 2015 studied chimpanzees (Pan troglodytes) and baboons (Papio anubis) in Gombe National Park (where Jane Goodall studied chimps) and found that they are exposed to a parasite called Cryptosporidium. Cryptosporidium is transmitted through food, water, and zoonotic means (from animals to humans).

Death from infectious disease is the leading cause of mortality for the three chimpanzee communities inhabiting Gombe (Lonsdorf et al., 2006; Williams et al., 2008), thus studying disease ecology should allow us to better conserve the Gombe population. While Papio anubis is not endangered, Pan troglodytes is.

Of the 131 non-human primates tested, 16% were positive for Cryptosporidium compared to 9.6% of livestock and just 4.3% of the 185 humans tested. Baboons and chimpanzees were infected at a similar rate. Three species of Cryptosporidium were detected: C. hominis, C. suis, and C. xiaoi.
 

Bush pig, Photo credit: Derek Keats

Half of the Cryptosporidium documented in the Kasekela community of chimpanzees are of a Cryptosporidium species (C. suis) typically associated with pigs. Surprisingly, C. suis was not detected in any of the humans, baboons, or livestock tested. The authors suggest that the transmission cycle may involve bush pigs, Potaochoerus larvatus, because domesticated pigs are not present in this area due to a mainly Muslim population. The bush pigs are found in the forest the Kasekela chimps inhabit and may serve as a reservoir for the parasite. It seems there are more details to be teased out when understanding the connection between C. suis and humans. Another species of the Cryptosporidium parasite found in this study, C. hominis, is one of two species most commonly found in humans (Chalmers and Katzer, 2013; Insulander et al., 2013). Yet C. hominis was also found in baboons and one of the chimpanzee communities, raising a red flag.

Cryptosporidium has been found in other primate species as well, including mountain gorillas, which were found to have the same species of Cryptosporidium, C. parvum, as found in nearby human populations (Nizeyi et al., 1999; Graczyk et al., 2001). Cryptosporidium has also been reported in red colobus and black and white colobus monkeys (Sayler et al., 2012). The Parsons study thus contributes to a growing body of literature on the prevalence of zoonotic diseases and their transmission. The authors stress the need to further understand the complex connections between primates, their ecology, their contact with humans, and the spread of disease so that we can better understand this relatively unexplored area of primate conservation.

This is an interesting article because Parsons and colleagues tackled a question that is poorly studied. The ecology of how diseases like Cryptosporidium spread and affect our primate relatives is not well understood, but zoonotic diseases make up the majority (60.3%) of emerging diseases worldwide (Jones et al., 2008). This is a timely and interesting paper that is worth reading or at least skimming. You can find the article posted online here. It's free and worth a look!

Links of interest:
Non-human primate biosafety from the University of Minnesota
Studying disease emergence in primates may help us understand emergence in humans
ScienceDaily article on paper


Sources:

Chalmers, Rachel M., and Frank Katzer. "Looking for Cryptosporidium: the application of advances in detection and diagnosis." Trends in parasitology 29.5 (2013): 237-251.

Insulander, M., et al. "Molecular epidemiology and clinical manifestations of human cryptosporidiosis in Sweden." Epidemiology and infection 141.05 (2013): 1009-1020.

Jones KE, Patel NG, Levy MA, Storeygard A, Balk D, et al. (2008) Global trends in emerging infectious diseases. Nature 451: 990–993 doi: 10.1038/nature06536
Graczyk TK, DaSilva AJ, Cranfield MR, Nizeyi JB, Kalema G, et al. (2001) Cryptosporidium parvum Genotype 2 infections in free-ranging mountain gorillas (Gorilla gorilla beringei) of the Bwindi Impenetrable National Park, Uganda. Parasitology Research 87: 368–370. pmid:11403378 doi: 10.1007/s004360000337 

Lonsdorf EV, Travis D, Pusey AE, Goodall J (2006) Using retrospective health data from the Gombe chimpanzee study to inform future monitoring efforts. American Journal of Primatology 68: 897–908 

Parsons, M. B., et al. "Epidemiology and Molecular Characterization of Cryptosporidium spp." Humans, Wild Primates, and Domesticated Animals in the Greater Gombe Ecosystem, Tanzania. PLoS Negl Trop Dis 9.2 (2015): e0003529.

Nizeyi JB, Mwebe R, Nanteza A, Cranfield MR, Kalema G, et al. (1999) Cryptosporidium sp and Giardia sp infections in mountain gorillas (Gorilla gorilla beringei) of the Bwindi Impenetrable National Park, Uganda. Journal of Parasitology 85: 1084–1088. pmid:10647041 doi: 10.2307/3285672 
Salyer SJ, Gillespie TR, Rwego IB, Chapman CA, Goldberg TL (2012) Epidemiology and Molecular Relationships of Cryptosporidium spp. in People, Primates, and Livestock from Western Uganda. Plos Neglected Tropical Diseases 6.(4):e1597. doi: 10.1371/journal.pntd.0001597. pmid:22506085

Williams JM, Lonsdorf EV, Wilson ML, Schumacher-Stankey J, Goodall J, et al. (2008) Causes of death in the Kasekela chimpanzees of Gombe National Park, Tanzania. American Journal of Primatology 70: 766–777 doi: 10.1002/ajp.20573

Connections between Ebola, primates, and the bush meat trade

You may or may not have heard by now that many outbreaks of the deadly Ebola virus originated when people handled or ate animals infected with the virus. For those who need a refresher, a virus is an infective agent that is only able to multiply inside a host's living cells; a virus may cause an infection or disease. Fruit bats, primates, porcupines, and other animals can all carry the Ebola virus. It is only when a person touches or ingests the infected animal's bodily fluids (blood, sweat, mucus, etc) that a person risks infection. So, if you pet a chimpanzee on the head, which you're not crazy enough to do, you wouldn't risk getting sick, even if that chimpanzee was infected with Ebola (unless that chimpanzee had a very sweaty head). If you ate that chimpanzee for dinner though, you would risk contracting Ebola.

You may prefer a steak from a cow, but not everyone does
Photo credit: public domain

And there lies the connection between primates, Ebola, and the bush meat trade. Bush meat, or meat from animals that are not domesticated (bred or trained to need and accept the aid of humans), can be a primary source of protein for those living in Africa. Animals may be hunted by individuals simply to feed their own family, or animals may be hunted for commercial profit. More and more urban areas are consuming bush meat though, and in some instances this meat is even seen as a prized delicacy, a symbol of status and wealth.

As you've probably realized by this point, the bush meat trade can cause several problems. For starters, people may consume animals that are endangered or threatened, lowering their already low numbers. In Africa, the bushmeat trade is the most significant immediate threat to wildlife. While hunting primates and other wildlife to feed your family may or may not be sustainable depending on how the quantity and frequency of hunting, the abundance of the hunted animal, and other variables, the commercial bush meat trade is definitely not sustainable. Infant primates or other young offspring will die if their mother is hunted, leading to more loss. Concerning today's topic though, consuming bush meat leads to the transfer of disease from animals to humans. Thus, the bush meat trade is not only bad for the wildlife in the dinner pot but it's also sometimes quite bad for the humans eating out of the pot.

Bush meat in Ghana

 While the Ebola virus is thought to have originated in fruit bats, primates and other animals can carry it as well. Primates are especially a problem because we're so closely related to them. It's very easy for us to contract diseases from primates compared to animals we're not as closely related to. You may have heard that we share 98% of our DNA with chimpanzees, for example. Well, this close genetic relationship means that many of the diseases we can contract can be contracted by non-human primates too and vice versa. Hepatitis and herpes B can be transmitted from animal to humans, HIV originated in chimpanzees as SIV, and tuberculosis or TB can easily be transmitted from humans to non-human primates.

So in areas where bushmeat is the only source of animal protein available, you may purchase some meat at the local market, take it home and serve it up to your family for a filling dinner, and have unknowingly served an animal that was sick and infected with Ebola. While at first it may seem easy to place the blame on those consuming bushmeat, remember that many have consumed bush meat before without getting sick and may not realize that this is how the disease is transmitted. Those selling bush meat depend on this income to support their families. If people are educated on how Ebola is contacted and how unsafe bush meat is, the demand for it will hopefully decrease, preventing future outbreaks. Providing safe sources of animal protein may be another step towards decreasing the demand for bush meat.



Food for thought: How does this post connect with cultural relativism?