Chimps get AIDS too

SIV, the simian form of HIV, causes illness in chimpanzees similar to human AIDS, despite the longstanding belief that such viruses had no effect on non-humans primates, according to a new study published this week in Nature. Image: linkurl:Flickr/belgianchocolate; "It's definitely unexpected,"

By | July 22, 2009

SIV, the simian form of HIV, causes illness in chimpanzees similar to human AIDS, despite the longstanding belief that such viruses had no effect on non-humans primates, according to a new study published this week in Nature.
Image: linkurl:Flickr/belgianchocolate;
"It's definitely unexpected," said viral immunologist linkurl:Don Sodora; of the Seattle Biomedical Research Institute, who was not involved in the research. "Prior to this it was thought that when African apes and monkeys were infected with SIV, there was no clinical disease." For nearly a decade, researchers have closely observed three free-living chimpanzee communities at the Gombe National Park in Tanzania -- home to the legendary work of primatologist Jane Goodall. More than 40 different SIVs naturally occur in dozens of African primate species, but they were universally believed to be virtually harmless. Linking viral infections in wild primates to slow-acting diseases such as AIDS is difficult, and captive, naturally infected chimpanzees did not show the characteristic decline in T-cell counts common in humans with AIDS. However, when AIDS researcher linkurl:Beatrice Hahn; of the University of Alabama at Birmingham and her colleagues noticed that chimps infected with SIVcpz -- the immediate evolutionary precursor to HIV-1 -- did not live as long as virus-free chimps, they started to question this longstanding assumption. "We saw that the number of chimps who had died in the infected group was about three times the number of chimps who had died in the uninfected group," Hahn said. "That was the first thing that really jolted us." That spurred Hahn to do a more formal mortality analysis. She found that chimps infected with SIVcpz were 10-16 times more likely to die in any given year than their uninfected group mates. Furthermore, fewer SIV-infected females gave birth to offspring, and none of the offspring born to infected mothers lived for more than a year. The team followed up these life history analyses with post-mortem histological investigations of three infected and two uninfected chimps, looking for "the tell-tale signs that had previously been described in humans with HIV-1 infection," Hahn said. Indeed, the infected individuals showed "hallmarks of HIV-1 infection," Hahn said, suggesting that chimps who contract SIVcpz in this population fall victim to an AIDS-like disease. All infected chimps had lower CD4+ T-cell counts and increased collagen deposition -- a sign of chronic immune activation -- in the spleen. In addition, the infected chimp with the most profound CD4+ T-cell depletion also showed lower counts other types of T cells, suggesting a more advanced form of the disease. That particular individual died less than three years after contracting SIVcpz, and became extremely thin and weak on the days leading up to her death. "Thanks to these painstaking behavioral studies and tracking of chimps in Jane Goodall's reserve, [the researchers] have been able to make these life tables and see that on average the chimps with SIV live shorter lives and are less fertile," said virologist linkurl:Robin Weiss; of the University College London, who was not involved in the work but wrote an accompanying review of the study. In addition, "the pathology looks vaguely like AIDS in humans." The magnitude of the SIV-induced illness is still unclear. SIVcpz appears to be less pathogenic than HIV-1, which increases the risk of death 18-20-fold in infected humans. One possible explanation for this difference is that SIVcpz and its chimp hosts have been coevolving for an estimated 500 years -- about five times longer than the 100 years since HIV jumped into humans. More time means more opportunity for the host to evolve mechanisms to cope with its unwanted invader. Additionally, 500 years is a relatively long time compared with other primate species affected by SIVs, which may explain why these chimps are getting sick at all, while others do not show any signs of illness, Hahn said. Regardless of the reason, "having a gradient of disease progression could potentially allow us the ability to figure out why some monkey species get sick and some don't," Sodora said. Identifying this pathogenic effect of an HIV-related virus in a species so closely related to humans "may give us a clue on how HIV-1 works," Hahn agreed.
**__Related stories:__***linkurl:New hope for HIV microbicide;
[4th March 2009]*linkurl:Impeding PD-1;
[ October 2008]*linkurl: Studying SIV to Understand HIV;
[2nd June 2003]


Avatar of: anonymous poster

anonymous poster

Posts: 2

July 22, 2009

I think it is very unfortunate that these poor animals are being infected with SIV or HIV just to proof that it affects them too. It rather would have been better to spend all that time and resources on meaningful research to find a cure or affordable vaccine. This research I am afraid, tends towards irresponsible science because it proves nothing and dose not unravel any of the mysteries surrounding HIV/AIDS.Bioethicists should call these researchers to order.

July 22, 2009

I am struck by this comment about SIVs: they were universally believed to be virtually harmless.\n\nIf I'm not mistaken, the article suggests that only in the last decade was it "noticed" that infected chimps might be affected. Where did the belief described above come from then? Has an untested assumption been presented as fact for three decades?
Avatar of: John Bush

John Bush

Posts: 3

July 22, 2009

SIV is not HIV and numerous bogus studies using SIV/HIV hybrids do not change that fact. Since when has a valid replicated study showed that SIV infections of human subjects produces the same symptoms in humans as HIV ?
Avatar of: anonymous poster

anonymous poster

Posts: 4

July 23, 2009

Please read the paper. These apes have not been infected by humans, they are free-living wild animals that happen to have several strains of SIV circulating whithin their population. The researchers were at pains not to disturb them, and determined SIV infection by sampling urine and faeces. Do you really think Jane Goodall would have her name on a study that involved voluntarily infecting her precious chimps with SIV/HIV?\n\nYou obviously haven't read the paper, and have no idea who the researchers are. Tip: GIYF
Avatar of: Jesse Creel

Jesse Creel

Posts: 12

July 23, 2009

Dear Dr Beatrice H. Hahn,\n\nThanks so much for your long and hard work showing that Chimps do get AIDS as well. Spoken to in the Scientist article below.\n\nYou are familiar with the citation below (Clin. Chem. 45:1602-1613.) from your article:\n\nJ Virol. 2003 July; 77(13): 7545?7562.\ndoi: 10.1128/JVI.77.13.7545-7562.2003.\n \nPMCID: PMC164799\nCopyright © 2003, American Society for Microbiology\nFoci of Endemic Simian Immunodeficiency Virus Infection in Wild-Living Eastern Chimpanzees (Pan troglodytes schweinfurthii)\n\n54.Urnovitz, H. B., J. C. Sturge, T. D. Gottfried, and W. H. Murphy. 1999. Urine antibody tests: new insights into the dynamics of HIV-1 infection. Clin. Chem. 45:1602-1613. [PubMed]\n\nClin Chem. 1999 Sep;45(9):1602-13.Click here to read Links\n Urine antibody tests: new insights into the dynamics of HIV-1 infection.\n Urnovitz HB, Sturge JC, Gottfried TD, Murphy WH.\n\n Calypte Biomedical, Berkeley, CA 94710, USA.\n\n BACKGROUND: Noninvasive methodologies provide alternatives to diagnostic blood tests and have high patient acceptance, increased safety, and reduced costs. Such tests may supplement or replace blood diagnostic assays currently in use. METHODS: Using a licensed urine-based test for antibody to HIV-1, we performed 25 991 HIV-1 urine antibody enzyme immunoassay (EIA) screening tests [confirmable by HIV-1 Western blot (WB)] on paired urine and blood specimens obtained from high- and low-risk HIV-1 subjects collected at six sites representative of the US population. RESULTS: Using HIV-1 urine EIA tests confirmed by urine Western blot, a compartmentalized immune response (urine positive/serum negative) occurred in 0.24% of a cohort of 11 896 subjects. In the same cohort, specimens that were urine negative/serum positive occurred in 0.17% of subjects. In a second study of 25 991 subjects that included 859 high-risk individuals, the false-positive urine EIA frequency (urine WB negative or indeterminate) was 1.3%. This false-positive frequency in the high-risk cohort was attributed, in part, to an IgA antibody response. We tabulated urine and serum indeterminate reactivities and examined their possible causes. Data are presented showing that antibodies from a seroindeterminate HIV-1vau group O subject were reactive in urine EIA and urine WB tests. An analysis of the HIV-1vau strain group O env nucleotide sequence disclosed a high frequency of homology with human chromosome 7q31, a fragile site implicated in many human malignancies. CONCLUSIONS: These results demonstrate the utility of urine for alternative HIV-1 antibody testing and provide new insights into the pathogenesis of HIV-1 infection and into potential application of this approach in investigation of other microbial pathogens and toxic compounds.\n\n PMID: 10471675 [PubMed - indexed for MEDLINE]\n \n\nIn this 1999 time frame, if my memory serves me correctly, Dr Howard Hurnovitz presented research, using the urine HIV-1 test he developed, showing that in the case of a female French farm worker with heavy organophosphate exposure, genetic recombination events between a SIVcpz endogenous retrovirus and segments of several human chromosomes occurred which gave rise to an "HIV-1vau group O" isolate.\n\nThis has intrigued me for some ten years now.\n\nThis being the case, could you kindly give me your thoughts on this as relates to possible HIV-1 Orgins?\n\nThanking you in advance.\n\nJesse Creel\nVaccine Research Advocate\n
Avatar of: Rick Bogle

Rick Bogle

Posts: 14

July 23, 2009

The main result is a likely spate of NIH-funded projects using chimpanzees. It would be worth reading Rachel Weiss's account of Jerom's miserable death, the only chimpanzee who sickened and died as a result of experimental infection with (a cacophany of) an HIV/SIV cocktail.
Avatar of: emma stokes

emma stokes

Posts: 1

July 30, 2009

Meaningful research to find a cure or affordable vaccine - that's precisely what they're doing. \n\nIf further investigation indeed confirms the finding here, and we discover that SIV in chimps is similar to HIV in humans then we have a good animal model to use in research to find a cure/vaccine/better drugs.\n\nAnimal testing will always be one of the first steps in developing new treatments and drugs, there are no viable alternatives at the moment. \n\nThere's the age old argument of using people - but i'm not sure many would volunteer, and even if they did humans make awful test subjects in these initial tests anyway - too many confounding factors!

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