Nanovaccine to boost poultry immunity

CHENNAI: Newcastle disease is one of the most common contagious diseases that affect poultry birds with a mortality rate as high as 90%. It often gets transmitted to workers who handle infected birds, leaving them with symptoms of conjunctivitis.High doses of avian vaccine had been used for more than 60 years, without much effect.
Now, researchers have developed a nanoparticle-coupled oral live vaccine that can prolong immunity in birds.Researchers in the Tamil Nadu Veterinary and Animal Sciences University have developed the vaccine with calcium phosphate nanoparticles. The nanoparticles, measuring 50nanometres (equal to one billionth of a metre), takes low virulent strains of the live virus in the vaccine directly into the cells of the birds. Hence, low doses of vaccine and fewer shots can be given compared to the conventional vaccine.
Director, Translational Research Platform for Veterinary Biologicals (TRPVB), Dhinakar Raj G said the abi lity of the nanoparticle to take the live virus directly into the cell and prepare the immune system for future attacks, does not let vaccine get neutralised by maternal antibodies. Conventional vaccine gets inactivated by maternal antibodies, which gets transferred from the hens to the chicks via eggs.
“We use calcium phosphate as nanoparticles as they are already present in the body . When it is coupled with live virus, it takes the virus into the cell,“ he said. “Since, it is biocompatible, it also does not need a receptor. So, there is a 100-fold reduction in dose of virus as well as number of shots given in the lifetime of a bird. The number of shots given in a bird's lifetime is also cut down by 40 per cent,“ he said. The nanoparticle vaccine, which has been under development for more than a year, is undergoing extensive field trials. Newcastle disease (ND) caused by virulent strains of avian paramyxovirus type 1 (APMV-1) causes symptoms of poor digestion, loss of appetite, heavy breathing, greenish droppings and, at times, bloody diarrhea.