Since the spring of 2010, outbreaks of duck Tembusu viral disease characterized by death, retarded growth, high fever, loss of appetite, and egg production decline hit the duck breeding areas in China. The disease is highly contagious and spread rapidly in ducks. The infection rate and morbidity of ducks was as high as 100% and mortality varied from 5% to 30%. Each year, duck Tembusu viral disease caused hundred millions yuan economic losses in China. So far, the disease is one of the most harmful infectious diseases in duck raising industry. It is a challenge to prevent and control duck Tembusu viral disease in China.

The virus was isolated and identified firstly by the scientists in Shangha Veterinary Research Institute (SVRI) of CAAS, and called formally as a strain of Tembusu virus (TMUV). Along with Dengue virus, West Nile virus and Japanese encephalitis virus, Tembusu virus belongs to the genus Flavivirus in Flaviviridea family. Tembusu virus can infect aquatic birds including ducks and geese and cause disease. Moreover, the isolation of this virus from chickens and sparrows suggests that host species are wide and potential hazard exists.

SVRI scientists conducted serial passages of Tembusu virus isolate (FX2010) in chicken embryo fibroblasts (CEFs) and obtained a non-pathogenic strain of Tembusu virus (Strain FX2010-180P) after several times purification. Although the non-pathogenic Tembusu virus cannot infect ducks intranasally or transmit between ducks, it has good immunogenicity and can induce high titer of neutralizing antibody. A live duck Tembusu viral disease vaccine was developed using the strain FX2010-180P. One-dose vaccination provided complete protection against the infection of Tembusu virus in half year.

Recently, the clinic trials of “Live Duck Tembusu Viral Disease Vaccine (Strain FX2010-180P)” were approved by the Ministry of Agriculture of China. The approval is a key step for this novel veterinary vaccine to be certificated and also bring a promising future for prevention and control options to duck Tembusu viral disease.