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New animal model is step closer to developing desperately needed vaccines

Texas Biomed scientists have discovered a new animal model which could be effective in research to combat deadly viruses that can be used by bioterrorists and for which there currently are no vaccines.

A study to be published in the Nov. 25 issue of the journal Virology reports that the common marmoset, a nonhuman primate, is susceptible to experimental infection with a family of deadly viruses, including Ebola virus and Marburg virus.

“The common marmoset is a smaller, less expensive and easier-to-use model in which the animal can be tested earlier in the disease process in order to develop a vaccine,” said Ricardo Carrion, Ph.D., a Texas Biomed virologist.

The report, with Texas Biomed scientist Jean L. Patterson, Ph.D., as co-author, was funded by the National Institutes of Health (NIH) and the Texas Biomedical Forum. The study was made possible using Texas Biomed’s biosafety level 4 maximum-containment laboratory.

The researchers found that inoculation with small amounts of Ebola virus and Marburg virus caused conditions in the marmoset similar to those observed in human disease. Most notably, animals experienced reduced blood platelet levels, a high number of white blood cells indicating infection, and clotting interrupting normal blood flow to body organs – all of which occur in humans afflicted with these  diseases.“Texas Biomed is working with the NIH and Defense Department to have a vaccine available for human clinical studies by 2015,” said Patterson. “We believe that the marmoset is a great model.”

Nonhuman primates are good models to study infectious disease because their immune system is similar to humans’ and they are good predictors of vaccine efficiency. The marmoset is a better model than other nonhuman primates such as macaques, which are more risky for transmitting certain diseases to humans and generally more difficult to handle.

Ebola virus and Marburg virus infection –  generally resulting from handling infected wild animal carcasses  – cause hemorrhagic fever, which begins with flu-like symptoms and progresses rapidly to the final stages of infection characterized by fever, bleeding, and severe low blood pressure that is fatal in 90 percent of cases.  No drug has been approved to treat Ebola virus or Marburg virus. People diagnosed with Ebola or Marburg virus currently only receive supportive care and treatment for complications.

The increased frequency of outbreaks of hemorrhagic fever caused by Ebola and Marburg central and western Africa and the potential use of such agents as biological weapons underscore the need to understand pathogenesis of these viruses and to develop effective intervention strategies. These viruses have also been responsible for an 88 percent decline in chimpanzee populations since 2003.

Texas Biomed, formerly the Southwest Foundation for Biomedical Research, is one of the world’s leading independent biomedical research institutions dedicated to advancing health worldwide through innovative biomedical research.  Located on a 200-acre campus on the northwest side of San Antonio, Texas, the Institute partners with hundreds of researchers and institutions around the world, targeting advances in the fight against AIDS, hepatitis, malaria, parasitic infections and a host of other infectious diseases, as well as cardiovascular disease, diabetes, obesity, cancer, psychiatric disorders, and problems of pregnancy.  For more information on Texas Biomed, go to, or call Joe Carey, Texas Biomed’s Vice President for Public Affairs, at 210-258-9437.