New treatment gives hope for serious horse disease
A research team from the Department of Microbiology at the Swedish University of Agricultural Sciences (SLU) has developed a breakthrough vaccine for the highly contagious horse disease strangles, caused by the Streptococcus equi bacterium. The results of the study, published in the journal Public Library of Science (PLoS) Pathogens, show that the new vaccine, based on recombinant DNA technology, is proving highly effective and may even lead to vaccines for streptococcal infections in humans. Strangles, also known as equine distemper, is every horse or stable owner's nightmare. Symptoms of the disease include high fever and swollen lymph glands in the horse's neck, leading to boils which then erupt. Occasionally boils become so large that they can cut off the air supply in the horse's trachea and stop its breathing. Most horses that contract strangles recover and then become immune, but in the worst cases, the horse dies. Antibiotic treatment against strangles is often ineffective. An outbreak of strangles can cause serious economic problems for stables as they have to go into quarantine for up to a year when a case is discovered. Horses that have the disease and recover can still spread the bacteria for up to 8 months afterwards. The disease is prevalent worldwide with around 100 cases reported in Sweden every year and more than 1,000 in the UK. Up to now, no safe and completely effective vaccine has been developed. The current vaccine is based on live bacteria and has been known to cause severe side effects. It also has only a short period of immunity. Now the research team from SLU has produced a vaccine based on pure proteins produced by recombinant DNA technology. The new vaccine is a combination of seven Streptococcus proteins. In tests the vaccine has proved highly effective and has shown no side effects. Horses injected with the vaccine were monitored over a period of three weeks for symptoms of strangles, and six out of seven horses vaccinated showed significant protection against the symptoms of the disease. All seven of the non-vaccinated horses became infected. The research team consisted of scientists from SLU, the Karolinska Institutet in Stockholm, Swedish pharmacological company Intervacc AB and the UK's Animal Health Trust. The team is confident it can have a new strangles vaccine on the market in the near future. The positive results also point to the possibility of developing other protein-based vaccines against Streptococcus infections in both animals and humans (these infections can cause illnesses such as tonsillitis and impetigo). Professor Bengt Guss from SLU, who led the research, said, 'This is a most exciting project, where basic research results in new applications and new knowledge can be used to develop vaccines against other bacteria. This in turn is highly important considering the increased number of infectious diseases caused by antibiotic-resistant bacteria.'
Countries
Sweden, United Kingdom