Chimpanzee, name unknown, subjected to a procedure
Photo: © Michael Nichols. From Brutal Kinship (Aperture)

Hepatitis research remains the largest single area of chimpanzee use in the United States.

Chimpanzees are most widely used in hepatitis C research but are also used for hepatitis A and B research. Nearly one-third of chimpanzee research dollars in 2003 and 2004 (an estimated $6 of $19 million and $5 of $15 million, respectively) went to hepatitis studies.

Hepatitis research on chimpanzees continues despite arguments challenging its scientific worth. As with the HIV virus, chimpanzees respond differently than humans to hepatitis.

After years of research on chimpanzees costing billions of taxpayer dollars, there is still no definitive cure. Human-modeled alternatives – a needed shift in research focus – are showing promise in prevention and treatment.

About hepatitis

Hepatitis is characterized by inflammation of the liver that can be acute and self-limiting, or chronic, degenerative, and fatal. It has a variety of causes including drug and alcohol abuse, drug toxicity, and a range of viral pathogens, the most common of which are known as hepatitis A, B, or C. Typical symptoms are jaundice, fever, and liver enlargement.

Hepatitis B (HBV), the most prevalent of the three, is the most common infectious disease in the world today. Two billion people worldwide have been infected with HBV. It is endemic in many countries, especially Southeast Asia. Over 350 million of those infected with HBV will have it for life and may eventually develop cirrhosis of the liver or liver cancer. (1)

Hepatitis C: pathophysiology and disparities between human and chimpanzee infection

Differences between HCV infections in humans vs. chimpanzees:

• 20% of humans with HCV develop cirrhosis of the liver, a chronic degenerative condition. Chimpanzees do not.
• Humans with HCV may progress to cancer of the liver. Rarely do chimpanzees.
• In humans the virus can transmit from mother to fetus. It does not for chimpanzees. (2)

Similar to the issues with HIV chimpanzee research, these differences call into question whether or not it is likely that a vaccine for human HCV will be developed using chimpanzees.

While studying the differences between humans and other species can inform science, it can (and has) sometimes led researchers to erroneous conclusions or dead ends.

Despite its limitations, well over $5 million in federal funding was spent on HCV research on chimpanzees in 2004 alone.

Breakthrough in cell cultures

In July 2005, hepatitis C researchers reported a breakthrough in the technology to grow the virus entirely in cell culture. (3) Increased funding should be channeled into human clinical studies and in vitro methods of growing infectious agents for research.

Hepatitis B: another case of inter-species disparity

Chimpanzees are also used for research on hepatitis B (HBV). As with HCV infection, the physiology of the chimpanzees’ response differs markedly from human infection. Essentially, a chimpanzee “infected” with HBV will not become sick while humans exhibit traditional symptoms of liver disease. (4)

Differences between HBV infections in humans vs. chimpanzees:

• Chimpanzees are essentially asymptomatic when infected; humans are not.
• Chimpanzees continue to produce the virus as long as it is in their body; humans do not.
• The liver, which is the organ primarily affected, is not affected in chimpanzees as it is in humans.
• Liver enzymes, which are measured to assess the progression of the disease, respond differently in humans and chimpanzees.

Chimpanzee researchers claim that the vaccine for hepatitis B resulted from chimpanzee experiments. However, chimpanzee use amounted to little more than using their bodies as test tubes to grow the HBV vaccine. It did not come about through studying the physiology of the disease in their bodies.

As noted by Americans for Medical Advancement, “If chimpanzees had not been used, the HBV vaccine would not have been developed as it was. It does not follow that it would not have been developed at all.” The first hepatitis B vaccine was made from the blood of infected humans and is now made from bacterial culture. (5)

For more information on this topic, read The Case to End Chimpanzee Research.

Number of hepatitis infected chimpanzees

According to its 1997 report on Chimpanzees in Research, the National Institutes of Health have indicated that “195 animals… participated in hepatitis virus research” at six research facilities.

The report also notes: “That number substantially underestimates the total used, because of normal attrition and the fact that many chimpanzees housed at New York University’s Laboratory of Experimental Medicine and Surgery in Primates (LEMSIP) were not counted but are known to have been used in HBV studies.” (6)

Given the prevalence of hepatitis C protocols currently funded by NIH – 25, 27, and 22 for 2002, 2003, and 2004 respectively – it is likely that the number of HCV infected chimpanzees is higher.

What happens to chimpanzees in hepatitis research

Hepatitis studies can be painful and grueling for chimpanzees. In addition to being isolated in sterile bio-containment facilities, the chimpanzees are subjected to frequent serial blood draws, other inoculations, and liver biopsies.

Liver biopsies are done using anesthesia and therefore require prior immobilization of the chimpanzee with a chemical agent (usually Ketamine). Lab technicians typically administer the drug to chimpanzees through a process known as “a knockdown” in which pre-loaded syringes are fired through a dart gun.

It is not unusual for a chimpanzee to be surrounded by laboratory personnel in order to be subdued or for the chimpanzee to be shot in vulnerable parts of their body  – while thrashing about futilely trying to avoid the dart gun – such as their eye or genitals, or even puncturing and collapsing a lung. (Some chimpanzees have been trained to accept injections.)

Chimpanzees who have lived through these ordeals and are now in sanctuaries are living testimony to the long-term trauma such procedures cause. Fauna Foundation in Quebec is currently home to 12 chimpanzees nearly all of whom have come out of labs. Extensive and detailed medical histories offer a window into their lives. Consider the story of Billy Jo as recounted by Fauna:

In 14 years at the lab, Ch-447, Billy Jo was knocked down over 289 times - 65 by dart with 4 or 5 men surrounding his cage pummeling darts into his body to anaesthetize him for a routine blood draw. In the lab he would shake his cage back and forth trying desperately to prevent anyone from approaching. To this day, Billy cannot bear to have strangers grouped in front of him.

In addition to several HIV challenges, Billy endured some 40 punch liver biopsies, 3 open wedge liver biopsies, 3 bone marrow biopsies and 2 lymph node biopsies with no tangible or practical results. He also chewed off his thumbs waking up alone from knockdowns when no one was around to care for him. During one fit of anxiety, he bit off his index finger. Anxious, aggressive, and fearful, Billy banged incessantly on his cage, rocking and staring into space when left alone. Even in sanctuary, Billy was plagued by anxiety attacks - attacks so bad that they left this majestic adult male chimpanzee choking, gagging and convulsing. (7)

In the experiment described below, published in the Proceedings of the National Academy of Sciences in 2004, three chimpanzees housed at BIOQUAL, Inc., a laboratory in Rockville, Maryland, were infected with hepatitis B and subjected to weekly liver biopsies, among other things. The study lasted 28 weeks.

Three healthy young adult HBV-seronegative [without prior infection] chimpanzees (Ch1615, -1627, and -5835) were used in this study… The animals were inoculated with 108 genome equivalents of a monoclonal HBV isolate (genotype ayw) contained in pooled serum from HBV transgenic mice. Before inoculation and weekly thereafter, blood was obtained by venipuncture and analyzed for serum alanine aminotransferase activity (sALT) as described. Six weeks after inoculation, Ch1615 and -1627 received three daily i.v. injections of either a humanized chimeric monoclonal anti-human CD4+ antibody (cM-T412) or an irrelevant control antibody, respectively, as described. The course of infection, inflammatory infiltrate, and kinetics of viral clearance were not affected in these animals… Before infection and each week thereafter, liver tissue was obtained by hepatic needle biopsy. In most instances, several tissue fragments 5 mm in length were obtained. (8)

Based on this information, we can estimate that each chimpanzee in this study was anesthetized with a dart gun 29 times during the six and a half months’ duration of the experiment. According to Fauna Foundation, “It can take up to five darts to put an adult chimp down. Some biomedical chimpanzees have been knocked down up to 220 times and have had over 130 liver biopsies done.” (9)

Hepatitis research without chimpanzees

It is claimed that chimpanzees are the only nonhuman animal capable of being infected with the virus for hepatitis C and other strains. While this may be true, it does not follow that the only way to pursue research into treatment for hepatitis is by infecting chimpanzees or that such research may lead to a cure (chimpanzees are also the only species who can be infected with the HIV virus, a point that proved irrelevant to their usefulness in HIV research).

Much hepatitis research today is carried out through observation and clinical trials on humans with hepatitis. Observation and analysis of a patient’s condition is, and always has been, a central component of medical research.

Examining the number of NIH funded projects for human clinical studies versus chimpanzee studies on hepatitis suggests that chimpanzees studies represent a small percentage of total studies. For 2004, 353 grants were awarded for human protocols versus only 22 for chimpanzee research. The chimpanzee studies comprise a mere 6.2% of the total areas of research. Human clinical studies comprise the remaining 93.8% of the research.

Number of human vs. chimpanzee CRISP* grants for hepatitis research in 2004:

Chimpanzees in HCV research are being used primarily as a medium, essentially living test tubes, in which to grow and observe the virus. As Dr. Ray Greek points out, progress on a HCV cure is likely being stalled by dependence on the chimpanzee model. He cites this lack of progress:

HCV effects more people today than it did in 1989. There is no vaccine and there is no cure. (10)

The millions of dollars spent on the inefficient and ineffective use of chimpanzees as “test tubes” should be channeled into developing efficient and ethical means of culturing the virus. See an example of two such studies.

FOR MORE INFORMATION:

• Learn about the recent trend that leads to repeated use of the individual chimpanzee for many experiments – a practice employed heavily for hepatitis research
• Read a scientific critique of the use of chimpanzees in hepatitis research and other biomedical projects
• See: Current NIH Funded Hepatitis Research Using Chimpanzees
• Read about alternatives to animal research

Last updated: 11/11/05

Sources

(1) http://en.wikipedia.org/wiki/Hepatitis

(2) Greek, R and Greek, J/Americans for Medical Advancement. (2005) “Hepatitis C and Chimpanzees in Research.” Retrieved from http://www.curedisease.com/articleHCV.html

(3) Lindenbach BD, Evans MJ et al, 2005. Complete Replication of Hepatitis C Virus in Cell Culture Science, July 22 309; 5734:623-626

(4) Ibid.

(5) Greek R, Shanks N, Greek J/Americans for Medical Advancement, (2005) “A Scientific Case for the Elimination of Chimpanzees in Research.”

(6) National Research Council, Institute for Laboratory Animal Research, (1997) “Chimpanzees in Research: strategies for their ethical care, management and use.” Table 2.1. National Academy Press

(7) Fauna Foundation, “Billy Jo History.” Retrieved at http://www.faunafoundation.org/english/sanct/chimps/billyjo.html

(8) Wieland S, Thimme R, Purcell RH, Chisari FV. (2004) Genomic analysis of the host response to hepatitis B virus infection. Proc Natl Acad Sci USA. Apr 27; 101(17): 6669-74

(9) Fauna Foundation, “Chimpanzees in the biomedical industry.” Retrieved at http://www.faunafoundation.org/english/sanct/chimps/biomedical.html

(10) Greek, R and Greek, J/Americans for Medical Advancement. (2005) Hepatitis C and Chimpanzees in Research. Retrieved from http://www.curedisease.com/articleHCV.html

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