Primatology.net

Plasmodium falciparum infecting Red Blood Cells

Plasmodium falciparum is the protozoan parasite that causes malaria in humans and ultimately the death of 2-3 million people a year. If you didn’t know, malaria is one of the most common infectious diseases and an enormous public health problem. Only one other malaria causing protozoan, a sister species of the P. falciparum parasite, P. reichenowi, was known to cause malaria but infects only chimpanzees. That was until researchers based in Gabon and France began sampling pet chimpanzees.

The team collected blood from 19 wild-borne animals kept as pets by villagers in Gabon, 17 of them being chimps. They found out that infected by a Plasmodium parasite, but sequencing of the parasite’s whole mitochondrial genome showed that it wasn’t P. falciparum nor P. reichenowi. Rather, it was a new species more closely related to P. falciparum. They classified the new species as P. gaboni.

Phylogenetic relationships among Plasmodium species (including P. sp_K) and associated host groups.

They have published their findings in the open access journal PLoS Genetics, under the title, “A New Malaria Agent in African Hominids.” You maybe asking why this is relevant to primatology? Many are against studies that use primates like chimpanzees because of ethical reasons. In situations like this, chimpanzees already infected with the parasite are useful to sample and study to shed light on the genomic adaptations of P. falciparum to humans and thus help in the discovery of new potential drug targets.

Ollomo, B., Durand, P., Prugnolle, F., Douzery, E., Arnathau, C., Nkoghe, D., Leroy, E., & Renaud, F. (2009). A New Malaria Agent in African Hominids PLoS Pathogens, 5 (5) DOI: 10.1371/journal.ppat.1000446

I have had the pleasure of working with Tierra Wilson for a couple years at the Gorilla Foundation. Since then, she’s moved off to veterinary school and I to graduate school. We’ve kept in touch and I was elated to hear that she’s going to Rwanda earlier this summer to study the mountain gorillas there. I didn’t know exactly what she’s up to until I came across Lucy Spelman’s blog post in Discover’s Quest: Gorillas in Peril.

The post, “Tierra’s Summer Project: Gorilla Saliva,” documents Tierra research project from inception to finish. She rounded up her own funding to travel and stay in Rwanda where she created a research project to detect infectious pathogens like herpes and influenza in the gorilla populations. As you may have read on this blog, infectious agents, especially pathogens from ‘human caused origins’ have caused a massive number of great ape deaths — especially in gorillas. Therefore, for any successful conservation effort, it is vital to be screening gorilla populations for any signs of infection. Current methods involve sampling fecal matter but previous research has shown that biomarkers for infection can be detected from saliva. After unsuccessful trials of sampling saliva from anesthetized gorillas, Tierra modified her approach using a method inspired from a publication on saliva collection in chimpanzees.

She designed a ‘a mesh bag with a juice-soaked rope,’ which the gorillas would chew to extract the juice from. The device actually sounds a lot like the enrichment activities she and the other gorilla caregivers like I did at the Gorilla Foundation. And it worked really well, she was able to detect alpha-amylase, an enzyme that is used as a biomarker for stress, i.e. a response to inflammation and infection.

Tierra Wilson Collecting Saliva From Mountain Gorillas in Rwanda, 2008. Picture: Dr. Lucy Spelman/MGVP

She extended her methods to wild populations, where she and the team, sampled several populations. When the Hirwa and Group 13 gorilla groups came down with respiratory disease, she also collected samples from them.

Her research project has since ended in Rwanda, for now, and the samples are currently being shipped back for more in depth analyses on various viruses, microbes, cortisol levels and gorilla DNA. I’m very proud to hear about her work she has done — especially on other primatology blog’s like Lucy Spelman’s. I’m even proud to say I know, “Hey, I know her and worked with her!”

Remember when I talked about the current state of using chimpanzee’s in biomedical research? If not, let me refresh your memory. About five months ago, I over-viewed the reasons as to why the United States is not using chimps as a model organism in biomedical research. At the core of it all, the issue for the moratorium was not as much ethical as it was more fiscal. I wish the NIH also took a stance in regards to the other issues, such as the ethics, in this situation.

Ever since 1995, research chimps have been prevented from breeding. A final decision has been made by the National Institutes of Health that chimpanzees will no longer be breed for research, according to Reuters. Kathleen Conlee of the Humane Society has commented on the issue,

“This decision is a huge step towards a day when chimpanzees are no longer used in invasive biomedical research and testing.

This will spare some chimpanzees a life of up to 60 years in a laboratory. While it doesn’t help chimpanzees already living in laboratories, it is a monumental decision.

Our ultimate goal is to put an end (to) the use of chimpanzees in research and retire those chimpanzees to permanent and appropriate sanctuary.”

I’ve mentioned in the previous posts where I covered this debate that I’ve always been a bit torn about using chimps in research. Often, they are kept in cages and scrutinized to invasive surgeries and treatments. By no means is the research done on them humane, especially since I know the psychological and emotional capacities of chimpanzees first hand.

However, I also know that chimps used in biomedical research aren’t thought of as disposable beings. They are used as important and valuable models to help understand very serious diseases such as HIV/AIDS and cancer. While it’s not ethically just to subjugate a being to torture, it is not right to abandon hope for treating terminal illnesses. I wish it really didn’t need to be reduced down to a issue of the lesser of two evils, but that’s how many people see it. It will forever remain a polarizing topic to me.

Going back to the news I’m sharing with you, I am happy to report that the governing body, a faction of the NIH, isn’t gonna just neglect the remaining research chimps. They say they are commitmented to maintaining the existing chimpanzee facilities, including the federal sanctuary for chimpanzees that are no longer needed in biomedical research.

I consider Pakinson’s a very devastating neurodegenerative disease because the affected individuals are fully aware of their degeneration. Unlike Alzheimer’s, where individuals become jaded as the disease progresses, individuals with Parkinson’s are very conscious of what’s happening or actually what’s not functioning correctly — and they can’t do a thing about it!

So some new findings from a biomedical/neurological experiment has just come out where the authors implanted dopamine generators (dopaminergics) into brain cells of macaques. They noted these new generators improved the symptoms of Parkinson’s. Here is a summary of the methods and findings,

“the research was extended to a greater number of non- human primates and for a longer period of time. The procedure involved implanting cell fragments extracted from the carotid body in the striate area of the brain. The carotid body is a small structure located at the bifurcation of the carotid artery, at the level of the neck. Its function is to control the rhythm of respiration and the cardiac frequency through releasing dopamine in situations of low oxygen level in the blood. After the implantation of the cellular aggregates of the carotid body into the striate area of the brain, the improvement in movement in monkeys with Parkinson’s and which had received transplants was demonstrated to last for at least a year.

The research team concluded that the mechanism by which the implants in the striate area of the brain of dopamine-generating cells manage to ameliorate Parkinson’s appears to be related to the capacity of these cells to release substances (trophic factors) that induce an increase of the dopaminergic cells (that usually exist in the normal brain but in lower quantities). Amongst these trophic factors is the GNDF (Glial Cell-derived Neurotrophic Factor).

Cells extracted from the carotid body have been used as a source for dopaminergic cells in the treatment of Parkinson’s disease in animal experiments and in humans. The advantage of this cell type with respect to others is the possibility of carrying out autoimplants, thus avoiding tissue rejection or immunosupressor treatment.”

Personally, I consider this an ethical use of primates in research. Firstly, the cause is noble in my opinion. Parkinson’s is a horrible disease, and in this situation, work done on a primate model has shown us a possible way to treat the disease by inserting doapamine generators. While, I think it will be a while until we actually do that in humans, this research has allowed a possible treatment to be investigated.

If you wanna read the entire publication, here is the a link to the paper, “Modification of the number and phenotype of striatal dopaminergic cells by carotid body graft.”

Science just published a whole slew of papers, posters, news articles, and the like on the Rhesus Macaque because the macaque genome, the first monkey genome to be sequenced, has been unveiled today.

I haven’t read all of the content in this special issue, but from what I have skimmed so far it’s all focused on the genome, of course, but also mobile DNA, genetic relations between two macaque populations, the roles of macaques in biomedical research etc. Rhesus macaques have been used as a model organism in biology for quite sometime, and this special edition of Science pays homage to this magnificent Old World monkey.

I’ve rounded up the links, if you’d like to click around and read some more about these monkeys:

• A Barrel of Monkey Genes
• Boom Time for Monkey Research
• Evolutionary and Biomedical Insights from the Rhesus Macaque Genome
• Mobile DNA in Old World Monkeys: A Glimpse Through the Rhesus Macaque Genome
• Poster: The Macaque Genome
• Evolutionary Formation of New Centromeres in Macaque
• Demographic Histories and Patterns of Linkage Disequilibrium in Chinese and Indian Rhesus Macaques

If you can’t check out all the content, I understand. I’ll be upset, but I’ll get over it. At the very minimum, you should check out the interactive poster that aids in

“exploration, as well as embedded video featuring seven scientists discussing the importance of the macaque and its genome sequence in studies of biomedicine and evolution. We have also created an accompanying teaching resource, including a lesson plan aimed at teachers of advanced high school life science students, for exploring what a comparison of the macaque and human genomes can tell us about human biology and evolution. These items are free to all site visitors.”

I’ve included a screenshot of to wet your monkey lovin’ appetite:

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.”

I’m opening this post to a discussion of using primates in research as seen in the following video.

Feel free to throw in your two cents… but let’s lay down some rules. In order to participate, first watch the video and then I’ll subjugate you to kindly read my previous posts on this subject matter. But for now, the video:

The posts you should read, or at least skim over, are these four posts on the ethics of using primates in research.

In this video we see how a monkey, looks like a macaque to me, is being used to conduct neurotech research. This type of research is a bit different from biomedical ones, but its applications are outstanding and the potential is nearly irrefutable.

There are many ‘pros’ to this video. As the commentators indicate, most of the these ‘pros’ reside on the fact that tests like these prove that humans without functioning limbs… be it due to paralysis or other forms of loss of function… can now use robotic arms to conduct daily tasks.

This research is very important, in my humble opinion. But it comes at a cost, and these costs are heavy moral ‘cons.’

See how the monkey is trapped in a box? Well it has to be, because I’m fairly sure sure it wouldn’t sit a second doing what the researchers wanted if it weren’t restrained. Also, there was some invasive surgery done. Electrodes are placed inside the monkey’s brain that interface between neurons and the computer and robotic arms… something that is more permanent than putting a monkey in a box for 30 minutes or so.

Knowing those basic pro’s and con’s, how do you feel about research like this? Should it be done in this manner? Do you see anything wrong with it? Do you feel this research is justifiable, given the potential benefits from it?

Late in 2006 we posted about a new question on Canada’s blood donor questionnaire and now it turns out that Ireland is following suit. Anyone who has handled monkeys or their bodily fluids will not be able to donate blood.

The reason is the same: the Simian Foamy virus.

It is noted that while the virus is common among those who handle monkeys, it does not cause any illness. However Dr. William Murphy, Medical National Director of the Irish Blood Transfusion Service states:

“But it (prevalence) is quite high and therefore professional monkey handlers have been excluded from donating.”

In addition to this news, the Irish Medical News reported another interesting bit of information. Those dealing with hemochromatosis (who are otherwise healthy and have donated within the past two years) are able to donate once again. With this genetic disease that effects more than 10,000 people in Ireland, the body absorbs and stores too much iron resulting in a necessary treatment of regular phlebotomies. A pilot scheme will open in 2007 for hemochromatosis donors in hopes of eventually screening the entire population. (For the USA, the Food and Drug Administration has always allowed those with hereditary hemochromatosis to donate blood, provided that the blood establishment follow procedures specific to their variance.)

With this in mind, we can hope that there will be improvement in the screening process for Simian Foamy virus so that those who have handled monkeys or their bodily fluids will not be eliminated as donors on that point alone.

We’ve heard of modern medicine helping zoo animals in many ways (including Salome, a western lowland gorilla at the Bristol Zoo reproducing with the help of fertility drugs) and the Port Lympne Wild Animal Park adds another success to the list: cataract surgery. A howler monkey named Tolkein relied on the help of her caregivers in daily activities since she developed cataracts as a juvenile.

The surgery restoring her eye sight was a success and after her recovery, Tolkein was introduced to a new arrival at the Wild Animal Park, Clyde. About a week ago, the two became parents of baby who is yet to be named…. a baby that Tolkein can care for with the help of all of her senses.

Simon Jeffery, a headkeeper at the Wild Animal Park reports that,

“At just a week old the baby seems strong and healthy and is very interested in its surroundings and so far Tolkein is being a perfect mum.”

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