New genetically engineered vaccines target Rift Valley fever
This is a scene from a Rift Valley cattle market. A new vaccine may help both cattle and people avoid the Rift Valley fever. Credit: Tilahun Yilma/UC Davis
(PhysOrg.com) -- Researchers from the University of California, Davis, and elsewhere are reporting the development of two genetically engineered vaccines to combat the mosquito-borne Rift Valley fever, devastating to livestock and so far confined to Africa and the Middle East.
The virus can sicken people, too, who can be infected by mosquitoes or by direct contact with infected animals or their meat.
The scientists from UC Davis, the University of Connecticut and the University of Texas Medical Branch hope the new livestock vaccines can be further developed for use in people.
There currently are no approved vaccines available for treating Rift Valley fever in humans, and those available for livestock are either inefficient or have serious side effects, said lead author Tilahun Yilma, a veterinary professor specializing in viral diseases and the director of the International Laboratory of Molecular Biology for Tropical Diseases in the UC Davis School of Veterinary Medicine.
Because Rift Valley fever is spread by mosquitoes, there is concern that the disease could be accidentally or intentionally introduced to North America and other regions where it is not now found, he said. Such an introduction could have devastating economic and human health implications.
Earlier in his career, Yilma did extensive work on foot-and-mouth disease and developed a similar genetically engineered vaccine for the devastating cattle disease rinderpest, which the World Organisation for Animal Health in May declared to be eradicated.
About Rift Valley Fever
Rift Valley fever is a viral disease first identified in 1931 among sheep in the Rift Valley of Kenya. Since then, outbreaks have been reported in Sub-Saharan and North Africa, and there was a major outbreak of the disease in 1998-99 in Kenya, Somalia and Tanzania.
In 2000, cases of Rift Valley fever were reported in Saudi Arabia and Yemen, the first reports of the disease outside of the African continent. This raised concern among health officials that the disease might spread to Asia, Europe and the Americas.
In livestock, the disease causes major losses due to illness, with the rate of abortion among pregnant sheep approaching 100 percent. In people, infection results in fever, hepatitis, vision loss and occasionally hemorrhagic fever.
About the new vaccines
In developing the two vaccines, the researchers made use of the vaccinia virus, the same virus used to make the smallpox vaccine. They inactivated two vaccinia genes to weaken that virus and prevent it from causing disease, and inserted two Rift Valley fever genes to stimulate an immune response, thereby equipping the vaccinated animals to fight off infection.
The vaccines are similar, except that one of them includes one more gene to further weaken the vaccinia virus and enhance the safety of the vaccine, especially for people who would be vaccinating livestock.
Both vaccines proved safe and produced significant immune responses when tested in mice and baboons, the researchers reported. When mice were challenged with the Rift Valley fever virus, the vaccines proved to be 90 percent protective.
In describing the advantages of the new vaccines, Yilma noted that both would be easy to produce in large scale and would not need to be refrigerated.
The researchers plan to conduct additional studies to determine how safe and effective the vaccines are in sheep and cattle.
Provided by UC Davis
- Virus death toll rises in Kenya Jan 26, 2007 | not rated yet | 0
- New vaccine strategies could safely control Rift Valley fever Jun 22, 2010 | not rated yet | 0
- East Africa and Middle East seek plan to keep animal diseases from disrupting livestock trade Jun 14, 2011 | not rated yet | 0
- Researchers examine role of climate change in disease spread Feb 05, 2009 | not rated yet | 0
- Climate change amplifying animal disease May 25, 2009 | not rated yet | 0
- Motion perception revisited: High Phi effect challenges established motion perception assumptions Apr 23, 2013 | 3 / 5 (2) | 2
- Anything you can do I can do better: Neuromolecular foundations of the superiority illusion (Update) Apr 02, 2013 | 4.5 / 5 (11) | 5
- The visual system as economist: Neural resource allocation in visual adaptation Mar 30, 2013 | 5 / 5 (2) | 9
- Separate lives: Neuronal and organismal lifespans decoupled Mar 27, 2013 | 4.9 / 5 (8) | 0
- Sizing things up: The evolutionary neurobiology of scale invariance Feb 28, 2013 | 4.8 / 5 (10) | 14
Classical and Quantum Mechanics via Lie algebras
Apr 15, 2011 I'd like to open a discussion thread for version 2 of the draft of my book ''Classical and Quantum Mechanics via Lie algebras'', available online at http://lanl.arxiv.org/abs/0810.1019 , and for the...
- More from Physics Forums - Independent Research
More news stories
(AP)—Alabama health officials say a mysterious respiratory illness has left five people hospitalized and two dead in the southeastern part of the state.
Diseases, Conditions, Syndromes 2 hours ago | not rated yet | 0
A paper recently published in the New England Journal of Medicine and co-written by physicians and scientists at the University of Colorado School of Medicine finds that an important genetic risk factor for pulmonary fibros ...
Diseases, Conditions, Syndromes 15 hours ago | not rated yet | 0
Using the Department of Defense Serum Repository (DoDSR), University of Cincinnati (UC) researchers have identified a number of biomarkers for inflammatory bowel disease (IBD), which could help with earlier diagnosis and ...
Diseases, Conditions, Syndromes 15 hours ago | 5 / 5 (1) | 0
(HealthDay)—Three-quarters of public schools in the metro Atlanta area contain microbes, including bacteria indicating the presence of fecal matter, according to research published in the May 17 issue of ...
Diseases, Conditions, Syndromes 16 hours ago | not rated yet | 0
(HealthDay)—Factors such as increased case finding may explain why Michigan had half of the total spinal infections associated with contaminated methylprednisolone acetate in the recent fungal meningitis ...
Diseases, Conditions, Syndromes 17 hours ago | not rated yet | 0
(Medical Xpress)—Scientists supported by the National Institutes of Health have a new theory as to why a woman's fertility declines after her mid-30s. They also suggest an approach that might help slow ...
1 hour ago | not rated yet | 0 |
(Medical Xpress)—A report published today shows a 2.6% decrease in the amount of alcohol sold per adult in Scotland in the year following the introduction of the Alcohol etc. (Scotland) Act in October 2011.
32 minutes ago | not rated yet | 0
(Medical Xpress)—High blood pressure is something that has traditionally been a problem in Scotland, but might there be a link to our climate?
22 minutes ago | not rated yet | 0
(Medical Xpress)—Health care spending is much higher for older Americans than for younger adults and children, on average, and analysts have said that increasing spending leads to longer life expectancy.
12 minutes ago | not rated yet | 0
The University of Gothenburg Vaccine Research Institute (GUVAX) announces successful results in a placebo controlled phase I study of an oral, inactivated Escherichia coli diarrhea vaccine.
52 minutes ago | not rated yet | 0
(Medical Xpress)—Preschoolers universally recognize that one's choices are not always free – that our decisions may be constrained by social obligations to be nice to others or follow rules set by parents ...
1 hour ago | not rated yet | 0