Ugh. I did put “pureed bee heads” in a title, didn’t I? How did I not see I was titillating to get attention, not to inform? A friend called me out on my last post. I was aiming to get across the awe I’d felt reading that paper and learning the very amazing ways scientists learn new things — such as testing the effects of chemicals on neurons by isolating them from the animal and measuring electrical activity. Amazing! My friend, however, saw a crass post encouraging a simplistic view of the complexities of research (especially the last line). By focusing on the gross-out aspect, I was encouraging a kind of science conversation that can’t talk about how and why we do research in favor of “shiny!” or “gross!”
So I screwed up (a bit). But the bonus is that now I have to write about research ethics. This post looks at animal research ethics by example: here’s a study and what they did and whether or not it seems ethical to me. For now, I’m going to avoid well-known historical examples: there are numerous cases of inappropriate methods on humans and other animals as well as good discussions for what went wrong. I’m also going to avoid (in this post) looking at ethics of research on humans in favor of focusing on how we treat animals.
Case: Does killing a small number of bees to study imidacloprid seem ethical?
First up, let’s take the research in the last post. One guiding principle in research ethics is that more intrusive or harmful methods need to be justified with strong societal benefits. In this case, the researchers wanted to better understand how the insecticide imidacloprid affects bees. By the time they were doing their study, the insecticide was already being used widely and there were concerns that it might be more dangerous to bees than other insects. Our agriculture is dependent on insecticides to maintain yields in the face of pest species so we (in general) need to allow their use. However, we must test them: instead of intentionally harming a small number of research animals and any target pests, we would be exposing all animals (including ourselves) to unknown risks. Research on insects and other animals to determine the effects of pesticides thus seems generally ethical.
However, just because we have a strong societal benefit to doing this research, still doesn’t mean it’s okay to kill these bees. Is this the only way we can figure out this question? In this case, the researchers are trying to understand how the chemical (and some other closely related chemicals) affect bee nervous systems which could help us mitigate harm to bees in the field. While I’m not an expert, it seems fairly hard to figure out the exact mode of action in the bee nervous system without isolating parts liked neurons and testing them. I can imagine that someday we might be able to grow bee neurons that never came from actual living bees and use those for research, we don’t have that today (so far as I know).
Finally, while bees are not exactly like us in their capacity to feel pain, it fits my sense of ethics that we should still minimize the harm we impose. In this study, the researchers used bees that were raised under proper conditions. The bees that were to be killed for my gruesome headline were frozen using dry ice which is, I’m given to understand, likely a low pain way for a bee to die. However, we really don’t know that much about invertebrates and pain. Moreover, while vertebrate research subjects (mammals, birds, etc.) have long had some legal protections on what is permitted to be done to them for research (and those protections have grown stronger over time), invertebrates have not historically been protected though it’s starting to change. That should help encourage more research to find ways to do research more ethically.
Overall, this research seems fairly useful to society, there don’t seem to be practical alternative methods and the bees were cared for in a humane way as far as we know. I’m comfortable saying these research methods were ethical.
Case: Was raising cancer-prone rats to test the effects of glyphosate-tolerant corn ethical?
You may remember a kerfluffle last fall when a study by a group of French researchers claimed that transgenic, glyphosate-tolerant corn (and glyphosate itself) caused cancer in a long-term feeding study. The study was widely criticized for poor experimental methods that likely made the results useless, as well as breathtaking media manipulation. Was it ethical to raise those rats and (ultimately) euthanize them for this study? Some were questioning whether the study was conducted in an ethical fashion right after it came out. Several of the many responses by other scientists specifically questioned the ethics of the study.
The first point to bring up is related to the criticized study design. In this study, the researchers raised animals that are prone to tumors well into their old age, then euthanized them for various samples. If we’re going to raise animals in captivity and then kill them, we should be sure we’re at least producing strong results. A widely criticized aspect of their study design was that they only used one control group for nine experimental groups per sex with variation in what the animals were fed (different amounts of GMO corn and amounts of glyphosate). Since each group had ten rats, that means there are 90 animals getting experimental treatments and only ten control animals to compare. Simply rolling dice will show you how easy it is for one or more of the nine groups of cancer-prone rats to show problems with an apparently more healthy control group. Nothing in the paper (or subsequent responses) have changed my mind that the study simply had poor design of experimental groups. If they couldn’t use more animals (fewer animals killed is better), they could have reduced the number of different treatment groups. Instead of having groups of rats each getting 11%, 22% and 33% of the GMO corn, they could have just done one percentage. That would have allowed more animals to be raised as controls, improving the study quality and ethics.
The second point was raised by several animal research ethicists. The Sprague-Dawley rat line used in this study are very prone to tumors: up to 80% or more will develop tumors over the period these rats lived, regardless of treatments. This raises an important ethical consideration: large tumors can be painful, cause skin lesions and impair movement of the subject animals, requiring that we do something to make them more comfortable. Sadly, the main option is often euthanasia and animal welfare guidelines for research purpose require that animals that are in significant pain be euthanized if they cannot be cured. The final study as published included photographs of some of the rats in the study, showing significant tumors. Many scientists who commented on the ethical issues noted that the photographs showed that the rats were not euthanized when they should have been. For example, one group of research pathologists wrote:
As most members of the ESTP are veterinarians, we were shocked by the photographs of whole body animals bearing very large tumors. When looking at the lesions, we believe those animals should have been euthanized much earlier as imposed by the European legislation on laboratory animal protection (http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri = OJ:L:2010:276:0033:0079:EN:PDF).
A similar response from a French group:
Last but not least, we were shocked at reading the ethical rules followed for euthanasia ("25% body weight loss, tumors over 25% body weight..." leading to euthanasia; Anatomopathology, §2.5) and at looking at Fig. 3J–L: the size of the tumors, with skin erosions and ulcerations, having certainly an impact on movement, feeding and pain, is unacceptable under well-known guidelines (Workman et al. 1998). This should have led to a much earlier euthanasia with respect to ethical humane concerns and casts doubts about the "careful monitoring" (Anatomopathological observations, §3.2) of animals. No argument, apparently to leave tumors develop as much as possible, should have prevailed. Again this demonstrates a lack of understanding of animal physiology and ethics, and a lack of supervision by the Ethical Committee and by a site veterinarian (“vétérinaire sanitaire”, a function mandatory under French law, see Article R203-1 5°). We are surprised that these major ethical issues were not clarified during the review that the paper underwent before approval for publication.
I don’t think this study was ethical. While there is public value in doing long-term studies on the effects of new foods, such studies must be done in an ethical manner. If this study had used proper experimental groups and the animals cared for appropriately (including appropriate euthanasia), I would probably have considered it ethical. The research team responded to some of the ethical concerns published in response to their original paper. I find their responses unconvincing and only increase my belief that this study was not run in an ethical manner.
Case: Is it right to capture and kill around 4% of the bats living in a cave to study a rare, but deadly, human disease?
Finally, I want to tell you about a borderline case where I’m just not sure. A major focus of the book Spillover by David Quammen are the behavior of possible reservoir species. Reservoir species are non-human animals who naturally carry an infectious organism (it may or may not cause significant disease in the animal) that can be transmitted to humans and ultimately causes disease. The rabies virus has a natural reservoir in bats which turn out to be very common reservoirs for diseases we get from animals.
In the book, Quammen describes cases where European or American tourists visited a Ugandan cave (called Python Cave — you can guess the attraction), went back home and subsequently became very ill or died. The disease they contracted is called Marburg virus (which is related to Ebola) and it causes significant, life-threatening illnesses. The likely reservoir for Marburg virus are bats but little is known about how Marburg virus infects bat populations Spillover is well-referenced, so I was able to look up one study on the bats in Python Cave.
The methods in this study are straightforward: go to the cave, collect a certain number of bats, and run tests on samples to try to detect Marburg virus in different tissues. However, these tests included taking samples (liver and spleen) that require killing the collected bats. Unlike the previous study, the authors are very forthright about the protocols they are conforming to and I have no reason to think the animals were mistreated thru improper techniques or inattention. All due care seems to have been taken.
However, the researchers collected 1,622 bats out of an estimated 40,000 bats living in this cave. That’s about 4% of them. That’s a lot of bats to kill. Was it absolutely necessary to collect so many bats? In order to get their exact results, it seems they did. The overall rates of infection they found were pretty low: out of those 1,622 bats, they only found 40 that seemed actively infected. The researchers were also able to identify different strains of the virus. This allowed them to show that the bats (or the virus at least) travel further than expected, including populations in Gabon. Further, the wide variety of strains in this single population of bats supports the idea that bats are the long-term reservoir of the virus. If they had collected fewer bats they might not have gotten a large enough sample to do this analysis.
But the question sticks in my head: could they have done it another way? Did they have to kill so many bats, who definitely feel pain and know when they are being hurt? Even more, Marburg is a relatively rare disease in humans. While it has a very high fatality rate (up to 88%), the number of known human fatalities is less than 400 cases since the 1960s. The earliest described cases are in Europeans handling infected primates with inappropriate safety protocols: those problems are largely fixed. Most of the ongoing cases are in people who work in caves (in generally awful conditions) in sub-Saharan Africa. Before this study, it was already known that the primary way humans are getting infected is by close contact with bats in caves. The solution would be for people either to not work in bat caves or to wear safety equipment. Knowing that Marburg virus is transmitted further than expected or having greater assurance that bats are a reservoir doesn’t help solve the social and economic problems that result in humans working without safety equipment in bat caves. That makes it harder for me to support killing so many animals for research.
But, I come back to what they are finding out. It’s really pretty interesting (and that paper is surprisingly readable). Maybe knowing more about how Marburg virus is transmitted in bats, including the different varieties of it, will eventually help us figure out effective treatments. But I’m conflicted. 1,622 bats dead is a lot of dead animals.
Updated 2013/03/08: The link to critical responses to the GMO corn feeding study was fixed.