Researchers from The University of Texas Medical Branch at Galveston have developed the first vaccine for chikungunya fever made from an insect-specific virus that doesn’t have any effect on people, making the vaccine safe and effective. The newly developed vaccine quickly produces a strong immune defense and completely protects mice and nonhuman primates from disease when exposed to the chikungunya virus.
The findings are detailed in Nature Medicine.
“This vaccine offers efficient, safe and affordable protection against chikungunya and builds the foundation for using viruses that only infect insects to develop vaccines against other insect-borne diseases,” said UTMB professor Scott Weaver, senior author of this paper.
Chikungunya is a mosquito-borne virus that causes a disease characterized by fever and severe joint pain, often in hands and feet, and may include headache, muscle pain, joint swelling, or rash. Some patients will feel better within a week but many develop longer-term joint pain that can last up to years. Death is rare but can occur.
Traditionally, vaccine development involves tradeoffs between how quickly the vaccine works and safety. Live-attenuated vaccines that are made from weakened versions of a live pathogen typically offer rapid and durable immunity but reduced safety. On the other hand, the inability of inactivated vaccines to replicate enhances safety at the expense of effectiveness, often requiring several doses and boosters to work properly. There may be a risk of disease with both of these vaccine types, either from incomplete inactivation of the virus or from incomplete or unstable weakening of the live virus that is only recognized when rare vulnerable individuals develop disease.
To overcome these tradeoffs, the researchers used the Eilat virus as a vaccine platform since it only infects insects and has no impact on people. The UTMB researchers used an Eilat virus clone to design a hybrid virus-based vaccine containing chikungunya structural proteins.
The Eilat/Chikungunya vaccine was found to be structurally identical to natural chikungunya virus. The difference is that although the hybrid virus replicates very well in mosquito cells, it cannot replicate in mammals.
Within four days of a single dose, the Eilat/Chikungunya candidate vaccine induced neutralizing antibodies that lasted for more than 290 days. The antibodies provided complete protection against chikungunya in two different mouse models. In nonhuman primates, Eilat/Chikungunya elicited rapid and robust immunity – there was neither evidence of the virus in the blood nor signs of illness such as fever after chikungunya virus infection.
Researchers from The University of Texas Medical Branch at Galveston have developed a vaccine against salmonella poisoning designed to be taken by mouth. The findings are detailed in an article published in Frontiers in Cellular and Infection Microbiology.
In earlier studies, the UTMB researchers developed potential vaccines from three genetically mutated versions of the salmonella bacteria, that is Salmonella Typhimurium, that were shown to protect mice against a lethal dose of salmonella. In these studies, the vaccines were given as an injection.
However, oral vaccination is simplest and least invasive way to protect people against salmonella infection. Taking this vaccine by mouth also has the added advantage of using the same pathway that salmonella uses to wreak havoc on the digestive system.
“In the current study, we analyzed the immune responses of mice that received the vaccination by mouth as well as how they responded to a lethal dose of salmonella, said Ashok Chopra, UTMB professor of microbiology and immunology. “We found that the orally administered vaccines produced strong immunity against salmonella, showing their potential for future use in people.”
There is no vaccine currently available for salmonella poisoning. Antibiotics are the first choice in treating salmonella infections, but the fact that some strains of salmonella are quickly developing antibiotic resistance is a serious concern. Another dangerous aspect of salmonella is that it can be used as a bioweapon – this happened in Oregon when a religious cult intentionally contaminated restaurant salad bars and sickened 1,000 people.
Salmonella is responsible for one of the most common food-borne illnesses in the world. In the US alone, the Centers for Disease Control and Prevention estimates that there are about 1.4 million cases with 15,000 hospitalizations and 400 deaths each year. It is thought that for every reported case, there are approximately 39 undiagnosed infections. Overall, the number of salmonella cases in the US has not changed since 1996.
Salmonella infection in people with compromised immune systems and children under the age of three are at increased risk of invasive non-typhoidal salmonellosis, which causes systemic infection. There are about one million cases globally per year, with a 25 percent fatality rate.
Learn more: UTMB develops an oral vaccine against Salmonella
The University of Texas Medical Branch (UTMB) is a component of the University of Texas System located in Galveston, Texas, United States, about 50 miles (80 km) southeast of Downtown Houston.
It is an academic health center with 11,000 employees and a medical school that is the oldest in Texas. In February 2015 it had an endowment of $513 million.
Established in 1891 as the University of Texas Medical Department, UTMB has grown from one building, 23 students and 13 faculty members to more than 70 buildings, more than 2,500 students and more than 1,000 faculty. It has four schools, three institutes for advanced study, a comprehensive medical library, three on-site hospitals (including an affiliated Shriners Hospital for Children), a network of clinics that provide primary and specialized medical care and numerous research facilities.
UTMB’s primary missions are health sciences education, medical research (it is home to the Galveston National Laboratory) and health care services. Its Emergency Room at John Sealy Hospital is certified as a Level I Trauma Center and serves as the lead trauma facility for a nine-county region in Southeast Texas; it is one of only three Level I Trauma centers serving all ages in Southeast Texas.
In fiscal year 2012, UTMB received 20 percent of its $1.5 billion budget from the State of Texas to help support its teaching mission, hospital operation and Level 1 Trauma Center; UTMB generates the rest of its budget through its research endeavors, clinical services and philanthropy. It provides a significant amount of charity care (almost $96 million in 2012), and treats complex cases such as transplants and burns.
In 2003 UTMB received funding to construct a $150 million Galveston National Biocontainment Laboratory on its campus, one of the few non-military facilities of this level. It houses several Biosafety Level 4 research laboratories, where studies on highly infectious materials can be carried out safely. It has schools of medicine, nursing, allied health professions, and a graduate school of biomedical sciences, as well as an institute for medical humanities. UTMB also has a major contract with the Texas Department of Corrections to provide medical care to inmates at all TDC sites in the eastern portion of Texas. UTMB also has similar contracts with local governments needing inmate medical care.
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