Primatology.net

A new Current Biology paper has documented what I’ve been following attentively sine 2006, the effect of exposure of human pathogens to great apes in the wild. The paper, “Pandemic Human Viruses Cause Decline of Endangered Great Apes,” is out on early advance release.

In order to thoroughly study the epidemiology of two communities of chimpanzees at the Taı National Park, a multidisciplinary approach involving behavioral ecology, veterinary medicine, virology and population biology was taken to track human disease. Tissue samples taken from chimpanzees that had died in a series of outbreaks dating back to 1999 tested positive for two human respiratory viruses that are major sources of human infant mortality in the developing world, namely human respiratory syncytial virus and human metapneumovirus. Viral strains sampled from the chimpanzees were closely related to pandemic strains concurrently circulating in human populations as far away as China and Argentina, suggesting recent introduction from humans into the chimpanzees.

The multidisciplinary research revealed an important distinction in issues revolving around ape conservation,

“The research project has however also had strongly positive effects. Longitudinal surveys showed that the presence of researchers had suppressed poaching activities in the surrounding area. Consequently, chimpanzee densities at both the research study site and a nearby chimpanzee tourism site were much higher than would be expected given their accessibility to poachers.”

In the past, I’ve covered on how the pathogens behind the diseases, Yaws, Ebola, and Anthrax have decimated ape populations. These three pathogens are affiliated with human society, specifically population density and sanitary as well as animal domestication issues. This new study specifically focused on the impact of human viruses to which wild great apes have little to none acquired immunity.

Here’s three posts where I covered the other diseases:

• Yaws disease among gorillas and the affect it has on reproductive success
• Ebola virus has decimated over 5,000 gorillas
• The role of Anthrax in the Great Ape Die-Off

According news bite of a long term study of Tibetan macaques (Macaca thibetana) in the Mount Huangshan Scenic Area of China’s Anhui Province, ecotourism is doing more harm than good. In the October edition of the International Journal of Primatology, the results of a 19 year long study will show that skyrocketing infant mortality coincided with an influx of ecotourism.

From National Geographic News,

“[Tibetan macaques] regularly compete for corn in a small open area within view of spectators. [Which] likely triggered adult aggression toward each other and toward their young… As a result, less than half of the infants survive into adulthood.

The results suggest that ecotourism can be deadly when not managed properly, said study co-author Carol Berman…

Berman’s team studied the Tibetan macaques for six years before ecotourism began in 1991.

They also collected data while tourists visited the animals between 1992 and 2004, including a span in 2003 when tourism was suspended.

Infant mortality had been low prior to ecotourism and was primarily caused by disease, the team found.

But exposing the monkeys to tourism was linked to high death rates caused by aggressive behavior among adults and toward infants. Although they didn’t witness all the attacks, many of the infant corpses Berman’s team found had bite wounds indicative of adult macaques.”

The National Geographic news piece on this publication goes on to interview Frans De Waal on his thoughts about ecotourism. He agrees with Berman that ecotourism works when it is managed properly.

The article goes on to cites that ecotourism for gorillas in Rwanda has helped out their case, but I beg to differ. We are seeing an influx of gorillas die from human acquired diseases. Many of these diseases like E. coli are not directly due to ecotourism, but other diseases… specifically communicable ones, take the common flu, can do serious damage to primate populations without acquired immunity to these pathogens.

In both of these cases, we see ecotourism not panning out to be what it was intended for — to spread awareness and help the conservation of primates. On the contrary ecotourism has serious side effects that we have no way of really calculating nor controlling.

Did you know that between October 2005 to September 2006, US airport inspectors “reported 50 incidents of discovered bushmeat, with each shipment averaging about 9 pounds? That works out to about one shipment being caught every week!”

That is what the CDC has reported in an article over at ABC News. The article, “Bushmeat: Curse of the Monkey’s Paw” reminds us that bushmeat trade is still prevalent, and there is an unusually high demand for this meat here in the US, which I outlined last year.

Aside from the ecological and conservation impact the bushmeat trade has made, it is an awfully disease ridden industry… one which potentially started off HIV/AIDS. This quote drives home the problem,

“But the amount of bushmeat discovered and confiscated by federal agents represents just the tip of the iceberg, said Heather Eves, director of the Bushmeat Crisis Task Force.

Based on “limited studies that we are aware of, it seems like [bushmeat sales on the U.S. black market are] on the order of 15,000 pounds a month,” she said.

Anecdotal evidence suggests a variety of ways the meat is smuggled into the country, Eves said.

“Carrying it in duty-free bags through customs, in luggage, shipping it in the mail and carrying it on their bodies. On the commercial level, shipments are often embedded in dried fish,” she said.

From there, it often finds its way into the markets of American cities that have large concentrations of immigrants from Western and Central Africa.

“We don’t have a handle on how much is coming in. The perception is that we’re only catching a fraction of what’s actually entering the country. It is difficult to know where to search. … There aren’t that many direct flights from Africa, but we’re wary of connecting flights,” said the CDC’s McQuiston.

The risk of diseases jumping from animals to humans is very real. In addition to the SARS and bird flu epidemics out of Asia in recent years, “it is generally understood that HIV arose through contact with nonhuman primates,” said Nina Marano, a veterinarian at the CDC.”

The article goes on to talk about Simian Foamy Virus, another topic we touched on too. But I appreciate William Karesh’s, director of the Department of Field Veterinary Programs at the Wildlife Conservation Society quote at the end of the article. He brings in how bushmeat, human population growth, and logging intersect,

“‘A lack of alternatives, a population boom and better access to forests along roads cut by logging companies’ have given people the desire and means to kill a diversity of wild animals…”

The science blogosphere has been buzzing about new published research that has focused studying the origins of a sexually transmitted disease, crabs which also known as pubic lice.

Before I talk about this paper I wanna thank Carl Zimmer, who opened up a public discussion with a question of the day: How Do You Get Crabs From A Gorilla? And that has been followed up with John Wilkins and Reed A. Cartwright throwing in some commentary. But that’s not it, some of the major news agencies like EurekAlert, Discovery Channel, and ScienceNOW Daily News have articles about this paper too.

The open access paper is titled, “Pair of lice lost or parasites regained: the evolutionary history of anthropoid primate lice,” and follows a simple premise, one that I’ve discussed about before. The authors basically take the concepts of genetic drift and integrate it into a study that reconstructs the evolutionary history of primate lice. They take this reconstruction and,

“infer the historical events that explain the current distribution of these lice on their primate hosts.”

Lice are a parasite that are limited in mobility. They do not have wings nor really effective bodies to move about. Their small legs are fit to latch onto a host and basically just stay put. Ultimately, the host becomes a village to these lice and a group of hosts become an island. Lice, therefore, begin to share the same evolutionary history as their hosts. For example, if a population of hosts splits into two and each of the isolated populations begins to evolve into separate species, then the parasites evolve too.

Two common types of lice are found on humans, head and pubic lice. Entomologists, or bug scientists, classified human head lice and human pubic lice in two separate genera because they are awfully different. Human head lice resemble chimpanzee head lice but human public lice resemble that of their gorilla counterpart.

This discontinuity between the two types of lice was curious to the authors of this paper. One would expect both types of lice to be more similar to chimpanzees since they are the closest evolutionary ancestor to us. So the authors of this paper, as Carl says it,

“set out to recover the evolutionary tree of pubic lice, just as they had done with head lice. They analyzed DNA from human head lice, human pubic lice, as well as other species from the same genera that live on chimpanzees and gorillas. They also analyzed DNA from lice that live on monkeys and on rodents so that they could get a better sense of how pubic lice had evolved from a common ancestor with other species. The scientists not only drew branches for each species, but also estimated when those branches split over the course of history.

Their conclusion… We did not get pubic lice from other hominids. We got them from the ancestors of gorillas.”

…Which is even more mind-boggling, this means gorillas and some hominid did the nasty. It seems that the authors took their curiosity and opened a Pandora’s box of disgusting-ness, but it shouldn’t be all too surprising.

Actually, in the last hundred years ago or so, humans transmitted what is now HIV from our chimpanzee counterparts, probably from some sort of sexual contact or blood exchange… And why that even happens in modern days opens a whole new discussion on gene flow and species concepts one that Wilkins addresses,

“Cross-species sex is a widespread phenomenon in vertebrate biology. We have been misled by our “intuitions”, based on the one hand on an over-strict application of reproductive isolation concepts of sex, and on the other of projection of moral standards.

Alan Templeton’s classic paper on species concepts has a section entitled “Too much sex”. It’s worth reading just for that.

Templeton, Alan R. 1989. The meaning of species and speciation: A genetic perspective. In Speciation and its consequences, edited by D. Otte and J. Endler. Sunderland, MA: Sinauer.”