Researchers at Yerkes National Primate Research Center, Emory University, contributed key comparative data for a landmark study showing African wild chimpanzees infected with simian immunodeficiency virus (SIV), an HIV-1-like virus, die prematurely and develop hallmarks of HIV-1 infection and AIDS.
This surprising discovery by scientists at the University of Alabama at Birmingham (UAB), and reported in the July 23 issue of Nature, alters the current view of AIDS virus infections in African nonhuman primates. SIVs are found exclusively in African nonhuman primate species and represent the original source of human immunodeficiency viruses (HIV-1 and HIV-2). Until now, scientists believed all African nonhuman primates naturally infected with SIVs, including chimpanzees, would not develop AIDS.
Beatrice Hahn, MD, a member of the Yerkes Scientific Advisory Board and a professor of medicine at UAB, and her researcher collaborators followed 94 free-ranging chimpanzees in Tanzania's Gombe National Park for nine years. They found SIV-infected chimps compared to uninfected chimps were 10 to 16 times more likely to die prematurely, experienced immune system failure and had lower birth rates and higher infant mortality. Laboratory tests revealed one chimp appeared to have end-stage AIDS.
The data the Yerkes Research Center contributed to the study was a comparison of the survival of SIV-infected and uninfected sooty mangabeys, medium-sized African monkeys important in AIDS research. Yerkes is uniquely suited to conduct AIDS research in nonhuman primates because it has large breeding colonies of both uninfected and naturally infected sooty mangabeys.
"As expected, there was no indication of increased mortality associated with SIV infection in sooty mangabeys," explains James Else, DVM, associate director for veterinary resources at Yerkes and a contributing author of the UAB study. "Sooty mangabeys can have a high viral load and chronic disease, but over many generations they have somehow learned to live with the infection and do not get sick.
"The value of Yerkes' research with natural nonhuman primate hosts of SIV, such as the sooty mangabey, cannot be overstated," adds Dr. Else. "You have two extremes: people who are infected with HIV and do not have access to appropriate medical care are dying at a high rate, and sooty managbeys with SIV are not dying at all.
"The mortality rate for SIV-infected chimpanzees is somewhere in between. As we better understand the mechanisms that enable the naturally infected sooty mangabeys to avoid getting sick and learn more about why the infected wild chimps are not getting as sick as people, we will apply that knowledge to Yerkes research focused on producing a vaccine that prevents people with HIV from getting sick," Dr. Else concludes.
For nearly eight decades, the Yerkes National Primate Research Center, Emory University, has been dedicated to conducting essential basic science and translational research to advance scientific understanding and to improve the health and well-being of humans and nonhuman primates. Today, the center, as one of only eight National-Institutes of Health-funded national primate research centers, provides leadership, training and resources to foster scientific creativity, collaboration and discoveries. Yerkes-based research is grounded in scientific integrity, expert knowledge, respect for colleagues, and open exchange of ideas and compassionate quality animal care.
Within the fields of microbiology, immunology, neuroscience and psychobiology, the center's research programs are seeking ways to: develop vaccines for infectious and noninfectious diseases, such as AIDS and Alzheimer's disease; treat cocaine addiction; interpret brain activity through imaging; increase understanding of progressive illnesses such as Parkinson's and Alzheimer's; unlock the secrets of memory; determine behavioral effects of hormone replacement therapy; address vision disorders; and advance knowledge about the evolutionary links between biology and behavior.
The Robert W. Woodruff Health Sciences Center of Emory University is an academic health science and service center focused on missions of teaching, research, health care and public service. Its components include the Emory University School of Medicine, Nell Hodgson Woodruff School of Nursing, and Rollins School of Public Health; Yerkes National Primate Research Center; Emory Winship Cancer Institute; and Emory Healthcare, the largest, most comprehensive health system in Georgia. Emory Healthcare includes: The Emory Clinic, Emory-Children's Center, Emory University Hospital, Emory University Hospital Midtown, Wesley Woods Center, Emory University Orthopaedics & Spine Hospital, the jointly owned Emory-Adventist Hospital, and EHCA, a limited liability company created with Hospital Corporation of America. EHCA includes two joint venture hospitals, Emory Eastside Medical Center and Emory Johns Creek Hospital. The Woodruff Health Sciences Center has a $2.3 billion budget, 18,000 employees, 2,500 full-time and 1,500 affiliated faculty, 4,300 students and trainees, and a $5.5 billion economic impact on metro Atlanta.