Dr. Tetsuro Ikegami, a University of Texas Medical Branch assistant professor and a Sealy Center for Vaccine Development member, who is part of a research team that is developing an improved vaccine for Rift Valley Fever virus, visited with Guidry News Service about the need for effective defense against the dangerous mosquito-borne pathogen, which can be used as an agent for bio-terrorism. Listen
Rift Valley Fever is a mosquito-borne virus that is prevalent in Africa. It causes fever in humans, inflicting liver damage, blindness and even death on a small percentage of the people it infects. The fever also afflicts cattle, goats and sheep, resulting in a nearly 100 percent abortion rate in infected animals. Its outbreaks periodically cause economic devastation in parts of Kenya, Somalia, Sudan and Zimbabwe, and bio-terrorism experts warn that its introduction into the United States would cripple the North American beef industry.
Dr. Ikegami said that the United States is not an endemic country for the disease but is susceptible to a bio-terrorism attack, which is why the National Institute of Allergy and Infectious Diseases has rated it a Category A Priority pathogen and the Centers for Disease Control and the United States Department of Agriculture are interested in his research.
He said the vaccine is spread naturally by mosquitoes, but its threat as a bio-terrorism weapon is as a powder.
“It’s kind of a different type of terrorism,” he said. “People may make powder; it can be transmitted by the air.”
Dr. Ikegami described his research at UTMB.
“Originally we first started working on molecular virology of the Rift Valley Fever virus, then we first tried to make a reversionary system for Rift Valley Fever and we successfully made a system to recover Rift Valley Fever virus from cloned sheep DNA,” he said. “As the next step we tried to improve currently available live attenuated vaccine for Rift Valley Fever.”
Dr. Ikegami said a vaccine developed 27 years ago has been central to the project.
“Our previous mentor, Dr. C.J. Peters, he actually made a very safe vaccine candidate named MP-12 strain,” Dr. Ikegami said. “That was made in 1985.” (Correct)
He said that the vaccine has been modified throughout the years.
He explained that MP-12 produces a strong immune response in humans and livestock, but that human safety trials of the vaccine have never been completed. In addition, if there were an outbreak at this time, public health officials would be unable to tell animals vaccinated with MP-12 from infected ones, making it impossible for them to map the epidemic’s spread and respond effectively.
Thus, Dr. Ikegami and his colleagues have removed a segment of the MP-12 genome designated NSs to differentiate the vaccine from the actual virus.
Also he said that it will be necessary for the new vaccine to be effective with a single injection rather than a series of shots.
A paper on the vaccine research is now online in the Journal of Virology. Click Here
Other authors of the paper include UTMB postdoctoral fellows Olga Lihoradova, Birte Kalveram, Sabarish V. Indran and Terence E. Hill, BSL4 lab manager Terry L. Juelich, Associate Professor Chien-Te K. Tseng, Assistant Professors Bin Gong and Alexander N. Freiberg, and Shuetsu Fukushi and Shigeru Morikawa of the National Institute of Infectious Diseases in Tokyo, Japan.
For the UTMB news release Click Here
Note: Molly Dannenmaier of UTMB participated in the interview.