Examples of Recent Experiments Using Non-human Primates
Below are samples of recent publications from laboratories in which non-human primates were used in experiments (see previous entries in our archives). Our intention is to provide details of the types of research to which non-human primates are being subjected. Bear in mind that what we list here is only a tiny example of the dozens of experiments published each week.
Although we emphasise welfare issues with respect to how the research impacted on the animals, please bear in mind that the non-human primates used were all essentially wild animals, even if bred in captivity. Because of this, the suffering and stress of being in captivity was inherent in every case.
This study was carried out at Vanderbilt University, Tennessee, supported by public funds and approved by the Animal Care and Use Committee at the Vanderbilt University Medical Center. The monkeys were used as an 'animal model' for noise-induced hearing loss. They were deliberately subjected to extremely loud noise of 141 or 146 dB with the intent to cause hearing impairment and cochlear damage to then assess their 'performance' on various audio-based 'tasks'.
One male rhesus and two male bonnet macaques were used in the research and five male rhesus macaques were used as 'controls'. Prior to exposing them to loud noise, each monkey had a 'head holder' surgically implanted into his skull. This device was used later during 'testing' so that the head was severely immobilised while the monkey was generally restrained in what is called an Audio Chair™ System, manufactured by Crist Instrument Co. The monkeys had been 'trained' to perform certain tasks, using fluid reward. Although not described, using fluid rewards almost always requires restricting water intake in order to 'motivate' the monkeys.
The exposure to the loud noise was done over a four-hour period, while the monkeys were sedated in a sound-proof chamber, with earphones deeply inserted into each ear canal. The noise was 141 dB (decibel - the unit used to measure the intensity of a sound) for one monkey and 146 dB for the other two individuals. The intent was to cause hearing impairment and cochlear damage.
The macaques, presumably including the individuals used as 'controls' for comparison, were killed after the experiments to study tissue related to hearing.
No information was provided on the clinical signs or description of the behaviour of the monkeys following the exposure to the noise and damage to their hearing. According to the Centers for Disease Control and Prevention, noise above 120 dB can cause immediate harm to a person's ears. The sound an engine produces when a jet plane is taking off creates 120 dB of noise and 140 dB is the noise to which you would be subjected by certain gunshots or firecrackers. Any exposure by humans to noise above 140 dB causes immediate hearing damage and pain. Noise above 140 dB is considered to be in the deadly range for people, leading to physical distress, shortness of breath, nausea, nosebleeds and other severe discomfort. Even below that level, noise can still cause permanent problems including hearing loss and persistent tinnitus. The monkeys in this experiment were allowed to live and suffer the effects of the loud noise damage to their ears – possibly with rupture of their eardrums – for many weeks.
The considerable and deliberate suffering inflicted upon these monkeys is highly distressing. These individuals were being used as surrogates for noise-induced hearing loss in people. We know, however, that sophisticated and morally defensible methods could be used to study people who have hearing abnormalities – such people have been studied for decades according to the researchers themselves. These studies would not only be humane, they would produce data that are directly relevant to people.
2020-11-01: "Mediterranean diet, stress resilience, and aging in nonhuman primates" Shively, Carol A.; Appt, Susan E.; Chen, Haiying; Day, Stephen M.; Frye, Brett M.; Shaltout, Hossam A.; Silverstein-Metzler, Marnie G.; Snyder-Mackler, Noah; Uberseder, Beth; Vitolins, Mara Z. and Register, Thomas C. Neurobiology of Stress 13:100254.
Forty-three female long-tailed macaques were subjected to the stress of laboratory conditions in order to study the diet of human beings, at Wake Forest School of Medicine, North Carolina. It was largely funded by the taxpayer and was approved by the Institutional Animal Care and Use Committee.
For 31 months, the macaques were fed one of two diets. One diet was a Western diet containing protein and fat mainly from animal sources and high in salt and saturated fats, said to be similar to that consumed by middle-aged American women. The other diet was a Mediterranean diet containing protein and fats derived mainly from plants with less salt and refined sugars than the Western diet.
The difference in reaction to chronic and acute stressful conditions was compared between the two groups of macaques. The researchers monitored chronic stress in macaques with subordinate status in their social groups, thus more likely to be a target of aggression, and acute stress by isolating individuals from their home group. The Mediterranean diet appeared to reduce the stress response.
Shockingly, three macaques, who were in the Mediterranean diet group and with subordinate status, died during the experiment. All three had diarrhoea and the researchers stated: Since they were thinner, they had less of a cushion to weather a bout of diarrhea. Social subordination stress may also have been a contributing factor.
The public are repeatedly told that non-human primates are used in research only when absolutely necessary and only when there are no other alternatives available. This shameful experiment, which resulted in the death of three monkeys, demonstrates the meaningless of such assurances. Not only is the information in macaques irrelevant to people given the fundamental difference in stressors between the two species, a clinical study could easily be done on relevant populations of people in order to get data that are directly applicable to people. The authors even acknowledged that many similar studies have already been done in people. The macaques in this study had to endure the stress of captivity, aggression from other monkeys, social isolation, and, for three individuals, death, for what can only be called frivolous reasons. Even worse, the authors are advocating further research to determine the effects of the diet on stress responses in male non-human primates. Their goal appears to be to create a model which can then be used for even more non-human primate research.
This recently published study provides a disturbing insight into the kind of ethanol (alcohol) research to which monkeys are being subjected at the Oregon National Primate Research Center (ONPRC) and paid for entirely with public funds (National Institutes of Health). It was approved by the institutional animal use committee of the ONPRC.
The ONPRC has been carrying out alcohol research on non-human primates for many years, including 'inducing' pregnant macaques to binge drink to look at the impact of alcohol on their foetuses.
Alcohol abuse is a serious illness suffered by millions of people, yet keeping monkeys in cages and forcing them to become 'alcoholics' in an attempt to help people is not only immensely cruel, it fails to address the human situation which is far more complex than simply the consumption of alcohol-containing drinks. Furthermore, research on mifepristone, the drug that was used in this monkey study, is already being studied in people as a treatment for alcoholism.
Twelve adult male rhesus macaques were used (nine described as ethanol drinkers and three as controls who had never had ethanol). The ethanol drinkers were coerced into drinking alcohol using food rewards and by slowly increasing the amount of alcohol in their only source of water. Eventually, the macaques were drinking up to 1.5 gm of 4% ethanol per kg body weight every day. Only after they had drunk the required amount of ethanol was plain water made available.
By six months, the average daily ethanol intake ranged from 1.64 to 4.02 gm/kg/day and the researchers described the monkeys as two light drinkers, one binge drinker, four heavy drinkers and two very heavy drinkers. Such a description appears to downplay the seriousness of what the monkeys were experiencing.
The macaques were then forced to undergo periods of forced abstinence where they were cut off from the ethanol, before being allowed access again. Mifepristone, the test drug, was given several times in food during these drinking trials to assess the impact on the amount of ethanol consumed by the macaques.
There is no information provided on the behavioural effects of ethanol on the macaques nor whether they showed signs of 'withdrawal' when ethanol was withheld. Withholding alcohol in alcoholic people can result in sweating, rapid heartbeat, hand tremors, problems sleeping, nausea and vomiting, hallucinations, restlessness and agitation, anxiety, and occasionally seizures. It is almost certain that the macaques would have experienced some of these effects, but with the added trauma of having no understanding of why and being confined in a cage. Although not stated explicitly, the use of the term necropsy several times in the report suggests that all the monkeys were killed at the end of the research.
The researchers reported that the test drug ...reliably decreases average daily ethanol self-administration in a non-human primate model but did not prevent or reduce relapse drinking. Foretelling more misery and death for other macaques, the researchers stated that ...additional research is needed to determine whether [mifepristone] can be an effective treatment...or would be safe for long-term administration.
As acknowledged by the authors, research on mifepristone to treat alcoholism in people is already being done. In one such study, the drug was found to be effective and well tolerated.
The test drug, mifepristone, is produced by Corcept Therapeutics and one of the authors has acknowledged being an employee at Corcept Therapeutics. This raises the issue of a potential conflict of interest by someone who appears to have a vested interest in the outcome of the work.
This recently published research involved rearing infant monkeys in low intensity lighting to find out whether it causes myopia (near-sightedness). The work was carried out at the University of Houston in the USA and involved researchers from the Brien Holden Vision Institute in Australia, a non-profit, non-governmental organisation. It was supported by public funds (the National Institutes of Health, the Brien Holden Vision Institute and the University of Houston Foundation). The research was approved by the University of Houston animal use and care committee.
Seven two-week-old infant rhesus macaques (Macaca mulatta) were used. The infants had been kept in what the researchers euphemistically called a primate nursery prior to being acquired for the experiment. Although not specifically stated, this strongly suggests the infants had been removed from their mothers soon after birth, certainly well before they reached two weeks of age. They continued to be subjected to maternal deprivation throughout the experiment. Forcibly separating infants from their mothers, and then depriving them of each other, is an extremely distressing experience for mother and infant, and one of the cruellest situations to which primates, including human ones, can be subjected.
At about 24 days of age, the infants were transferred to another nursery in which there was reduced lighting (during typical 'daylight' hours, then the lights went off during typical 'night-time' hours). They remained under these conditions (except for brief removals to do measurements on ocular development) for the remainder of the experiment (until they were about 10 months or 310 days of age). The overhead lighting in the room during 'daylight' hours was only 55 lux, but the amount of light as measured at the fronts of the cages was only seven to 36 lux; this is completely aberrant for the normal habitat in which rhesus monkeys live. In addition to being kept under these dim conditions, infants were denied the nurturing and security of their mothers and the companionship of each other. The authors state: Our rearing environment was very dim in comparison to typical outdoor lighting levels. In this respect, our light levels were just above twilight light levels typically encountered outdoors...Moreover, our lighting levels were dim in comparison to indoor lighting standards. The minimum lighting recommended for people in a work area is 100 lux, but as much as 500 lux if they work in an office. In a previous study, the authors stated that typical laboratory lighting levels averaged 580 human lux. These infant monkeys, therefore, had to endure not only the distress of social and maternal deprivation and a completely abnormal environment for their well-being, but also the near-dark conditions. Control data were acquired from age-matched monkeys who were reared similarly, but under typical laboratory lighting.
For the periodic tests to measure ocular development, the infants were injected with a sedative (ketamine) and their heads were covered with a light-blocking cloth while they were transferred to the measuring facility to collect data, including inserting contact lenses. These tests were carried out every two weeks for the first seven months, then every month until the end of the experiment. No information was provided as to the fate of the seven infant monkeys.
The authors found that dim-light rearing of these monkeys did not result in myopia, rather it subtly altered ocular structure and optical refraction (bending of light). No tests were done to determine if any of this had any effect on vision for these individuals; all the measurements were physical, not functional, in nature.
The data derived from this inhuman treatment of infant monkeys are essentially valueless. The authors even acknowledged this:
A limitation of our study was that the illumination level, as well as the duration of exposure, was not representative of real-world scenarios. In addition, whereas transitioning between relatively lower and higher ambient lighting frequently takes place in daily life; our subjects were deprived of such opportunities. Transitioning between ambient lighting conditions might be physiologically impactful because temporal contrast might serve as an additional trigger for retinal dopamine release. These limitations suggest that the observed refractive effects of dim lighting might be largely exaggerated.
Furthermore, research has already been done in people to show that an increase in ambient light protects children from developing myopia. Why, therefore, were these infant macaques deliberately caused to suffer when not only are the data not applicable to people (or even other species of monkeys: These results showed that, for rhesus monkeys and possibly other primates... [emphasis added]), but it was already known that it is important to provide adequate light in human children in order to promote normal development in refractive ability? This is work simply designed to continue using non-human primates as 'models' for human refractive error development, as alluded to by the authors.
Vision research on infant macaques, involving some of the US and Australian authors of this study, has been carried out over many years, also publicly funded by grants from the National Institutes of Health, funds from the Vision Cooperative Research Centre in Australia (Brien Holden Vision Institute) and the University of Houston Foundation. One such study involved rearing infant monkeys with red filters over one or both of their eyes. The filters were held by goggle helmets that provided monocular and binocular fields of view. Except for brief periods needed for routine cleaning and maintenance, the monkeys wore the helmets continuously from about 25 to 146 days of age.
It is disturbing that researchers appear to have a casual approach to the removal of infant monkeys from their mothers. This type of research, which is of no medical value to human patients, but of enormous psychological cost to the monkeys, should be discontinued. The authors, however, advocate the carrying out of further similar research using non-human primates.
2020-08-01: "Transient-mixed Chimerism With Nonmyeloablative Conditioning Does Not Induce Liver Allograft Tolerance in Nonhuman Primates" Chaudhry, Sulemon; Kato, Yojiro; Weiner, Joshua; Alonso-Guallart, Paula; Baker, Sam; Woodland, David C.; Lefkowitch, Jay H.; Duran-Struuck, Raimon; Sondermeijer, Hugo P.; Zitsman, Jonah; Sears, Mallory L.; Wu, Anette; Karolewski, Brian; Houck, Philipp J.; Martinez, Mercedes; Kato, Tomoaki; Sykes, Megan and Griesemer, Adam D. Transplantation 104(8):1580-1590.
This recently published research took place at Columbia University in New York. It was supported by the US taxpayer and was approved by the Columbia University institutional animal care and use committee. Fourteen long-tailed macaques (Macaca fascicularis; from Charles River Primates, Wilmington, MA) were used; seven as 'donors', seven as recipients. In order to 'condition' the monkeys for liver transplant surgery, all 14 animals were subjected to massive irradiation in order to disrupt their immune system. This included the entire body and the thymus (a gland involved in the immune system). They were further immunocompromised by being poisoned with a compound that destroys T-cells (the compound was a Pfizer drug called ATGAM®) and metabolic toxin (cyclosporine; used to treat cancer by destroying certain immune cells). Some monkeys also received further drug treatment in order to alter their immune response. After the monkeys were 'conditioned', they were subjected to substantial intervention and complex surgery to remove the liver and bone marrow from 'donors' and implant into the recipients. This resulted in all the 'donor' monkeys being killed on the surgery table.
Very little was reported on the postoperative conditions for the monkeys; nothing at all about how the monkeys fared, their appearance or their behaviour. However, a description of some of the complications following the transplantations graphically illustrates the appalling nature of the suffering and misery these intelligent and sensitive animals must have experienced. For example, bleeding could not be stopped in one monkey, who then was subjected to a splenectomy. Another monkey never even made it off the surgery table due to an "anesthetic complication" which resulted in the monkey being killed. Another monkey developed serious problems with the lungs and was killed due to respiratory complications four days after surgery. Another was killed on day 10 after surgery due to bleeding. A fourth individual suffered an anesthetic complication during additional surgery and was killed. Out of the remaining monkeys who were still alive, one was killed on day 57 after the recurrence of an earlier complication and another had to be killed on day 69 following a rejection complication.
The monkeys continued to be immunosuppressed for 28 days after transplant surgery. When this was stopped, all the livers in the recipient animals were rejected. Thus, the protocol being tested to see if it would improve acceptance of the livers did not work as hypothesised. What did happen, however, is that 14 monkeys had their lives taken from them, but not until they had been subjected to 'treatment' that caused extreme suffering, including radiation that crippled the immune system, poisoning and many hours of complex surgery and days of recovering from such surgery. For the seven individuals who received the liver transplant, their lives were impacted further by post-transplant complications resulting in a major departure from their normal health. Seeking new and improved medical interventions and treatments for human suffering, illness and disease is important. Action for Primates, however, believes that it is morally unacceptable to do so by purposefully inflicting suffering, illness and disease on another species, especially one who has been shown to suffer similarly to people.
This research was a cruel and shocking waste of life. Twenty-three female monkeys suffered the trauma and loss of having their babies taken from them and 23 baby monkeys were purposefully killed at just 6 months of age for a human infant formula that is already on the market. The study involved Abbott Nutrition infant formula products and was funded by Abbott Nutrition and the US taxpayer (National Institutes of Health).
The research was carried out at the Oregon National Primate Research Center in the USA. At birth, the infant monkeys were assigned to one of three trademarked diets: Similac Advance with OptiGRO (eight monkeys), Similac Advance base formulation (seven monkeys) and a combination of monkey breast milk and Fiber-Balanced Monkey Diet 5000 [LabDiet] (eight monkeys). The research was carried out to look at different nutrients. All 15 infants who were fed the commercial human infant formula were removed from their mothers at one day old and kept in what was euphemistically called a "nursery". The eight infants who had the combination diet were allowed to be with their mothers for six months before being taken away and killed with the other 15 individuals. Forcibly separating infants from their mothers, and then depriving them of each other, is an extremely distressing experience for mother and infant, and one of the cruelest treatments to which primates, including human ones, can be subjected.
Researchers will often try to justify using non-human primates in research by arguing how similar they are to people. It is, however, precisely these similarities that make their suffering and use so unjustifiable. Like people, non-human primates carry with them the underlying abilities to feel pain; to suffer; to experience anxiety, fear and depression; to show signs of experiencing joy or enjoyment; to provide human-like care for others of their own kind. They are our closest biological relatives in the animal kingdom and to treat them in this way is disgraceful.
In addition to the inhumane nature of the research, Action for Primates believes that the results cannot be extrapolated to human infants whose metabolism, nutrient requirements and, in particular, social environment, would be completely different. Further, the Abbott Nutrition products are already in use for human infants and data for people have been and could continue to be derived from sophisticated studies on infants.
2020-06-30: "Auditory representation of learned sound sequences in motor regions of the macaque brain" Archakov, Denis; DeWitt, Iain; Kuśmierek, Paweł; Ortiz-Rios, Michael; Cameron, Daniel; Cui, Ding; Morin, Elyse L.; VanMeter, John W.; Sams, Mikko; Jääskeläinen, Iiro P. and Rauschecker, Josef P. Proceedings of the National Academy of Sciences of the United States of America 117(26):15242-15252.
The work was carried out at Georgetown University Medical Center, Washington, DC, but also involved researchers from Finland (Aalto University School of Science). As with virtually all research on non-consenting beings, it was approved by an institutional committee, in this case the Georgetown University Animal Care and Use Committee.
This research was funded in part by the US taxpayer (National Institutes of Health and National Science Foundation). Some of the researchers were additionally funded by the Academy of Finland (a government funding body).
The researchers wanted to know why non-human primates do not have a more speech-like (or song-like) communication system, including vocal learning and volitional control, despite their anatomical similarities to people.
Snapshot from video clip https://doi.org/10.1073/pnas.1915610117
Three rhesus macaques, named Do, Ra, and Ch by the researchers, were used in this experiment. They were initially 'trained', using food and fruit juice as 'rewards', to do certain tasks on what the researchers called a "monkey piano" – a keyboard device designed specifically for this research. In this video clip included in the publication, one monkey can be seen rotely pressing levers that produce sounds and then reaching for a bit of food presented on each correct sequence. The researchers did not state whether the macaques were initially subjected to fluid or food reduction or deprivation in order to 'motivate' them to carry out behavioural tasks, although this is commonly used in laboratories and is often the only way to get the animals to 'cooperate'. The research took place in the laboratory cages and sound booths.
Once they were 'trained', posts were surgically implanted into the monkeys' skulls and secured with ceramic bone screws, plastic strips and bone cement. These 'head posts' were used, in conjunction with a restraint device euphemistically called a 'primate chair' by researchers, to prevent the monkeys from moving their heads during the testing. From the visual media documented in the publication, it is clear that the monkeys also had to endure the continuous presence of a metal neck-collar.
After recovery from the surgery, the monkeys were restrained in a horizontal position in the 'primate chair', with their heads immobilised using the implanted posts. Shoulder electrodes were also applied to record muscle activity. Whole-brain functional magnetic resonance imaging (fMRI) was used to study the monkeys while they were presented with the sounds they had 'learned' (or ones they had not) through in-ear headphones to see if the researchers could identify how the information was being processed in the brain. The macaques had to endure hundreds of trials during multiple scanning sessions.
The researchers claim their study shows that macaques can learn to produce novel sound sequences with their hands by pressing levers ("piano keys") on a keyboard.
The public are repeatedly told that non-human primates are only used in research when absolutely necessary and only when there are no other alternatives available. We do not know if the researchers in this study would offer that defence, but it is patently clear that the work has no importance to non-human primates and certainly has no applicability to people. Furthermore, the same sorts of studies could easily be done in people – and have been done – to see what part of the brain is involved in various activities, including playing the piano (1), using the same kinds of sophisticated methods used by these researchers. Such studies provide the kind of information what would actually help people. It is shocking that, instead, these intelligent and sentient beings were cruelly exploited in this experiment. They were not only deprived of a normal life, they also had to endure surgical mutilation, extreme restraint and the monotony of hours of 'trials'.
Researchers in Korea, who support the reduction of canine teeth in non-human primates, have subjected 10 male macaques (8 rhesus and 2 long-tailed) to major mutilations of canine teeth to study the impact of the surgery. This recently published work was carried out at the Biomedical Research Institute at the Seoul National University Hospital, South Korea and was approved by their Institutional Animal Care and Use Committee.
Mutilation of macaque teeth
The removal or reduction of healthy teeth of non-human primates for non-medical reasons, such as in a laboratory or a private home in which a monkey is being kept as a 'pet', is a major welfare and well-being issue and is not supported by many, including the American Veterinary Medical Association (AVMA) who believes the practice is inappropriate for humane and safety reasons (1).
Tooth abscess
The oral surgery was carried out to cut off the outer part of the canine teeth and to expose the pulp. Some of the pulp was removed and the teeth were capped. The researchers had to use cotton soaked in a blood-clotting agent to stop the bleeding from the tooth during surgery. The monkeys were monitored from two months to two years and five months. One monkey developed a tooth abscess after the surgery.
The authors acknowledge the limitations of the research. Tooth abscesses usually occur two to three years after canine teeth reduction, but only two of their monkeys could be observed past two years. This means that the authors do not know whether their means of tooth reduction might, in addition to the immediate problems, result in serious oral disease later. Incredibly, the other limitation was that the authors had no access to a dental radiograph machine. An important part of all dental work is the use of radiographic images to study the progress of a condition.
This casual approach to inflicting additional pain and suffering on non-human primates for an 'experiment' that was simply done to see if mutilating the canine teeth would result in a 'safer' situation for people with respect to being bitten by the monkeys is shocking. The authors even acknowledged that the issue of tooth reduction is an animal welfare issue and that the procedure is "soundly opposed" by the AVMA and the Association of Primate Veterinarians, is rarely done or approved by institutional animal care and use committees in the US. Their justification that the procedure "...may have value to institutions outside of the United States of America" fails to recognise that it matters not where the monkeys reside: they suffer similarly.
2020-06-01: "Remdesivir (GS-5734) is Efficacious in Cynomolgus Macaques Infected with Marburg Virus" Porter, Danielle P.; Weidner, Jessica M.; Gomba, Laura; Bannister, Roy; Blair, Christiana; Jordan, Robert; Wells, Jay; Wetzel, Kelly; Garza, Nicole;Van Tongeren, Sean; Donnelly, Ginger; Steffens, Jesse; Moreau, Alicia; Bearss, Jeremy; Lee, Eric; Bavari, Sina; Cihlar, Tomas and Warren, Travis K. The Journal of Infectious Diseases ePub.
This experiment was carried out to study the effectiveness of remdesivir in macaques deliberately infected with Marburg virus, some of whom were left untreated. Remdesivir is an antiviral drug developed by Gilead Sciences, and, according to a conflict of interest statement, five of the authors of the paper were current or former employees and may be shareholders in the company. The remaining authors were from the United States Army Medical Research Institute of Infectious Diseases (USAMRIID) and The Geneva Foundation. The research was funded by taxpayer money.
Marburg virus causes a highly virulent disease which results in haemorrhagic fever, with a fatality rate of up to 88% in people. The Marburg virus is classified as a Category A biowarfare agent by the Centers for Disease Control and Prevention (CDC) and there are no vaccines or effective therapies currently available (1).
In the experiment, 24 long-tailed macaques (Macaca fascicularis) supplied by Worldwide Primates, Florida, were deliberately injected with the Marburg virus and kept in a biosafety level 4 (BSL-4) laboratory at USAMRIID, Frederick, Maryland. Eighteen of the monkeys were given different doses of the test treatment (remdesivir) starting 4-5 days after the virus injection. The remaining six individuals, who were 'control' animals, received no treatment. Blood was taken from each animal via a leg vein on days 0, 3, 4, 5, 6, 7, 8, 10, 14, 21, 28, 35, and 41 post-inoculation. When blood was taken, the monkeys were given ketamine.
According to the published research, all the 'control' monkeys developed acute signs characteristic of Marburg virus disease infection, such as fever and rash, behavioural depression and deteriorating physical responsiveness. They were either allowed to die or were killed 7 or 9 days after infection because of the severity of their suffering. Many of the monkeys who had received treatment also became ill (although they had an "increased survival" rate) and died or had to be killed. All monkeys who were still alive at the end of the observation period were killed for further study. The postmortems carried out showed that some of the animals had incurred major organ damage as a result of the virus.
According to the CDC, the onset of symptoms for Marburg virus disease in people is sudden and includes fever, chills and muscle pain, followed by nausea, vomiting and diarrhoea. The illness becomes increasingly severe and can include substantial weight loss, massive hemorrhaging, shock, liver failure and multiple organ dysfunction (2). Given that the Marburg virus infection in the monkeys in this experiment was stated to have caused disease similar to that in people, we have to assume that at least some of these gruesome and highly painful conditions described by the CDC were present in the monkeys. The monkeys were not stated to have received any medication to ease their suffering.
Dr Nedim Buyukmihci, Emeritus Professor of Veterinary Medicine, UC Davis California and representative of Action for Primates, who has reviewed the publication, stated: There is no doubt that these macaques suffered horrendously during this experiment. Unfortunately, this is not an isolated situation and many thousands of other non-human primates are caused to suffer greatly as a result of the search for treatment and vaccines against viruses such as Marburg, Ebola and, most recently, the coronavirus responsible for Covid-19. Although the search for treatment or vaccines against such viruses is crucial to reducing suffering and death in people, we should not be causing equal or greater suffering in others such as non-human primates. Aside from the moral implications of using non-human primates in this way, there is also the sound scientific argument that animal research cannot be relied upon to produce safe and effective treatments for people. As moral and intelligent beings, we need to employ research methods that are humane and effective without intentionally causing suffering and death in others.
Nick Atwood, Animal Rights Foundation of Florida, said: We are saddened by the Florida connection to this experiment that resulted in the horrible suffering and death of many monkeys. The use of monkeys in the search for a Marburg virus or COVID-19 vaccine is not only cruel, but is unnecessary and often produces misleading results. We need to focus instead on human-based research methods.
Remdesivir was originally developed as a treatment in people for Ebola and Marburg infections, but did not demonstrate clinical efficacy (3). Research with remdesivir has since been revived with the outbreak of Covid-19 (4).
Scavone C, Brusco S, Bertini M, Sportiello L, Rafaniello C, Zoccoli A, Berrino L, Racagni G, Rossi F, Capuano A. Current pharmacological treatments for COVID-19: What's next? Br J Pharmacol. 2020 Apr 24:10.1111/bph.15072. doi: 10.1111/bph.15072. Epub ahead of print. PMID: 32329520; PMCID: PMC7264618.
Williamson, B.N., Feldmann, F., Schwarz, B. et al. Clinical benefit of remdesivir in rhesus macaques infected with SARS-CoV-2. Nature (2020). https://doi.org/10.1038/s41586-020-2423-5
This work is written by (a) US Government employee(s) and is in the public domain in the US.
Pneumonic plague is a severe lung infection that, if left untreated, can very quickly become fatal. It is caused by the bacterium Yersinia pestis. Symptoms in people include fever and headache, developing into pneumonia with shortness of breath, chest pain and cough. Pneumonic plague can be fatal within 18 to 24 hours of disease onset if left untreated, but strong antibiotics, such as ciprofloxacin and levofloxacin, can effectively cure the disease if they are delivered early.
In this recently published experiment, 79 African green monkeys (Chlorocebus aethiops) were used. They were all infected with a known lethal dose of the bacterium through inhalation in a head-only aerosol exposure chamber. The animals were divided into two groups, each group receiving either ciprofloxacin or levofloxacin as a treatment. Each group also contained eight monkeys who acted as a 'control' and received no treatment.
This research was funded by the taxpayer and took place at the National Institute of Allergy and Infectious Diseases, Rockville, Maryland, USA.
The objective of the study was to see the effects of delaying treatment with ciprofloxacin or levofloxacin after the onset of fever. This was an especially inhumane experiment because survival was the primary endpoint. The monkeys were observed for 21 or 28 days post-infection. Five animals died before treatment was begun. Fourteen of the treated animals and all 16 of the 'control' animals died. Of the latter, some were allowed to suffer for as long as 76 hours after the onset of fever. Any surviving animals at the end of the observation period were killed.
The authors do not mention the clinical signs shown by the monkeys after infection and before their death. The only reference is: Animals that did not survive until the time of scheduled euthanasia were either found deceased or found to be moribund and euthanized ahead of schedule.
There is no question, however, that these monkeys suffered substantially, without any attempt to alleviate this. The rapid deaths, the use of 'control' animals receiving only a placebo and the focus on survival as the endpoint all present a disturbing picture of the way in which these monkeys were treated, as if they were mobile Petri dishes rather than sentient, intelligent beings. We can safely assume that, like people, monkeys infected with pneumonic plague suffer from fever, headaches, shortness of breath, chest pain and cough.
Aside from the appalling suffering these monkeys endured, what is also shocking is that a) the two antibiotics - ciprofloxacin and levofloxacin - are already on the market and used to treat pneumonic plague in people, and b) it is already known that early intervention with antibiotics is essential and effective against pneumonic plague in people (1).
Reference:
WHO. 2017-10-31. "Plague" World Health Organization accessed 2020-06-26
Antibiotic treatment is effective against plague bacteria, so early diagnosis and early treatment can save lives.
This recently published study was done at the Washington National Primate Research Center in Seattle, using public funds and was approved by the Institutional Animal Care and Use Committee at University of Washington. Three infant rhesus macaques were used. Two had muscles to their eyes cut during their first week of life to make them have strabismus (misalignment of the eyes, commonly known as 'squint'); the third was the normal 'control'. Once the monkeys were older (at around 3 years), they were subjected to surgery to implant head posts and recording chambers for brain electrodes, all into the skull. They also had scleral search coils surgically implanted into both eyes (under the conjunctiva) to measure eye movement. The head posts "allowed the head to be restrained during experiments." The experiment involved using visual stimuli and recording what went on in the brain. The monkeys were killed at the end of the experiments.
Although aimed at understanding amblyopia (a specific vision defect caused by 'squint') in children, the cruel method used on these baby monkeys resulted in a completely artificial situation. The experimental creation of 'squint' is fundamentally different from that naturally occurring in children. Further, and critically, there are substantial data already available from human studies and similar data can continue to be derived by such studies, data that will help children, rather than continuing to cause suffering in non-human primates.
In addition to being in captivity, these monkeys, as new-born infants, had to suffer damage or disruption to their vision either through cutting or paralysing the eye muscles or being forced to wear prism goggles. They also had to endure multiple surgeries and being restrained severely during the experiments; some individuals were used in several experiments over a number of years. All were then killed. We do not know if the new-born infants were also deprived of their mothers as this is not stated in the published work. Infant non-human primates have been used for decades in a misguided attempt at understanding human vision. Such research is not only morally reprehensible, it creates artificial situations that have little resemblance to what naturally occurs in human children. Where is the 'care' and oversight from the institutional animal care committee?
This was publicly funded research to look at the impact of drinking alcohol in early pregnancy in an attempt to simulate human foetal alcohol spectrum disorder (FASD). Rhesus macaques "induced" to binge drink (roughly 6-7 alcoholic drinks, an amount known to cause intoxication in people) every day from before becoming pregnant and through the first trimester of pregnancy.
The experiments took place at the Oregon National Primate Research Center (ONPRC), a publicly funded entity and further supported by multiple grants from the National Institutes of Health (NIH). Twenty-eight rhesus macaques, presumably bred at ONPRC (source was not stated in the papers), were used. Half of them were "induced" (authors' term) to drink ethanol (alcohol) by using a food-reward system and eventually having alcohol-containing water as their only fluid source. When the monkeys consistently drank enough of the alcoholic fluid to achieve 1.5 grams of alcohol/kg body weight every day, this degree of daily alcohol consumption was continued for at least 30 days prior to conception and through 60 days of pregnancy (which is the 1st trimester in this species). The other half of the monkeys were "controls" and drank equivalent amounts of a non-alcoholic fluid each day.
The monkeys were individually housed in 76 x 60 x 60 cm stainless steel cages. Given that the average size (head and body length) of a female rhesus macaque is about 50 cm, this provided very little room even for normal postural adjustments and none for any meaningful exercise. Although other monkeys were in the same room and could be seen or heard, no socialisation such as touching or grooming, critical to monkey well-being, was allowed.
During gestation, the foetuses were examined by using magnetic resonance imaging (MRI) on the mothers. Normal birthing was not allowed. Instead, the foetuses were surgically removed at 85, 110 and 135 days gestation, killed and their brains examined to see if the alcohol consumption by the mothers caused any abnormalities and to see if MRI might have predicted such damage.
In addition to the major welfare issues for the monkeys, the work is seriously flawed because it is looking at a highly singular situation of just the effects of alcohol in a rigidly controlled environment. This in no way comes close to mimicking the situation for women in whom many other factors would modulate the effects of alcohol use, whether positively or negatively. These include environmental pollution, diet, the use of tobacco products (smoking), the taking of various medicines, the use of other drugs (such as marijuana, cocaine, etc), a person's psychological state (for example, if their life is extremely stressful for other reasons). Furthermore, the authors acknowledge that their 'sample size' was too small to reach any definitive conclusions even in their tightly controlled 'model', citing the cost of using monkeys as the major issue.
The authors point out that, due to its non-invasive nature, MRI could be used to study human foetuses that have been exposed to alcohol in utero to address the challenge of early detection of abnormalities. Such studies could provide information relevant to people rather than wasting resources on and causing suffering in monkeys. Instead, the authors state that future research using monkeys is anticipated, including allowing alcohol-treated mothers to give birth, so that their offspring can be studied.
This was publicly funded research to look at the effects of a nutrient restricted diet on the foetuses of pregnant baboons. After being fed such a deficient or control diet, 42 baboons had their uterus cut open under anaesthesia. The 42 unborn foetuses, some near full term, were killed while still attached to their mother.
Female baboons (Papio sp.) from a baboon colony maintained by the Southwest National Primate Research Center at the Southwest Foundation for Biomedical Research in Texas, USA, were used in this research. The researchers were attempting to simulate intrauterine growth restriction (IUGR) in humans, a condition involving the poor growth of a foetus while in the mother's womb during pregnancy. The research was funded by the National Institute of Health (NIH). Female baboons are regularly used in research for human female reproduction studies.
For the purposes of the research, the female baboons (between 8-15 years old) were allowed to become pregnant by being placed in groups with a male baboon. Once pregnant, about half the females were fed a control diet and the rest were fed an experimental maternal nutrient restricted (MNR) diet (70% of normal caloric intake), starting on gestational day 30. At gestation days 120, 140, 165 and 175, the baboons were anaesthetised and each had her uterus cut open. The foetuses were killed by being bled to death through the umbilical cord and then removed from their mother's womb. The normal gestation period for baboons is about 175-180 days (6 months), which means that some of the foetuses were almost at full term when they were killed. The mothers' surgical wounds were repaired. After recovery from anaesthesia, the mothers were returned to individual cages and eventually returned to their group cages. The tissues from each foetal group were compared.
We believe this was an appalling waste of life. The authors had already done studies in human volunteers (pregnant women with normal or growth-restricted foetuses), the results of which are clearly more applicable to human beings and which did not involve the suffering of intelligent and sentient beings who could not give their consent, and the subsequent deliberate killing of their unborn babies.
Eighteen long-tailed macaques were subjected to hypobaric hypoxia when forced into high altitude research that simulated travelling rapidly up to 7,500 metres (over four miles), thus reducing the concentration of available oxygen. Hypobaric hypoxia is a condition where the body is deprived of oxygen, causing severe brain injury and abnormal behaviour.
The monkeys were held at this 'altitude' for 48 hours and then killed. Six additional 'control' monkeys were also killed after three days. Some of the monkeys received drug treatment to see if it altered the effects of lack of oxygen.
The monkeys suffered substantially. The authors reported that monkeys ...lost their balance and lay prostrate with limited body movements and that All six monkeys in the [untreated hypobaric] group displayed anorexia, vomiting, motor deficits, and ataxia.
There was an acknowledgement by the authors as to how dire the situation was for the monkeys with the statement: Because of safety concerns for the experimenters, the altitude was decreased from 7 500 m to 6 000 m for blood collection and drug administration... [emphasis added]
The authors also acknowledged that the findings in monkeys were already known in people: In this study, we demonstrated that cynomolgus monkeys exposed to acute [untreated hypobaric] exhibited various symptoms, including anorexia, vomiting, motor deficits, and ataxia, as observed in human patients suffering acute high-altitude diseases and which are mostly attributed to pathological changes in the brain (Wilson et al., 2009).
The work was done at the Third Military Medical University in Chongqing, China, and one of the authors was funded by a grant from the Carlsberg Foundation (the principal shareholder in Carlsberg A/S - the global brewing group). According to the Carlsberg Foundation Website: The Carlsberg Foundation supports visionary and innovative international basic research within the natural sciences, social sciences and humanities. Basic research that makes us smarter, helps us to address global challenges and benefits society.
It is appalling that these animals were deliberately subjected to such cruel research resulting in considerable suffering and distress deliberately prolonged for 48 hours.
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