Recently, the "Notice on the Prevention and Control of Seneca Virus Diseases by the General Office of the Ministry of Agriculture and Rural Affairs" was announced. The Seneca virus has been prevalent mainly in Brazil, Canada, the United States and other countries, but it is reported that it has been introduced into China and sporadic in a small area. The research on the virus is not enough so far, the risk of the disease is difficult to predict, and there is no exact prevention and treatment measures, so the farmers should strengthen prevention.

1. What is the Seneca virus?
The symptoms of pigs infected with Seneca virus are very similar to those of foot-and-mouth disease. Ulcers and blisters appear in pigs' hoofs and nasolabial lenses, causing pigs to suffocate and even worse, death. The Seneca virus was first discovered in March 2015 in a pig farm in Guangdong, China, and Seneca virus (SVV) was isolated from the pathological material. According to the information received by Prof. He Dongsheng, Veterinary Medical College, Agricultural University of South China, in March 2016, a large number of sows and fattener in a large pig farms developed vesicular infections with an incidence rate of 100% and a mortality rate of 40%. After laboratory testing, using a variety of techniques and repeated experiments, the similar pathogens such as foot-and-mouth disease and blister disease were excluded and it was finally determined that this was a disease outbreak caused solely by the Seneca virus.

2. Can Seneca virus cause serious harm?
In pigs infected with Seneca virus, the main symptoms are hoof crown, nasolabial lens and oral mucosa growing ulcers and blisters, with hoof shells fall off, difficulty standing, elevated body temperature, listlessness, anorexia, etc. Research on mortality is not enough. In the outbreak of Fujian, China in 201, some fatteners and sows with more than 150 kg showed the above symptoms. After 10 days, the blisters were scarred, and neither piglets nor weaners were ill. There is no death in the affected pigs. Another epidemic occurred in Fujian Province in the same year, both large and small pigs were ill. In the case of virus regression experiments, large pigs did not develop, but suckling piglets developed and died. Tests have shown that both the nose and the intramuscular route can cause blisters and death in the suckling pigs. After testing, the oral and nasal secretions, urine, and blood of the affected pigs contain viruses.
The clinical symptoms caused by Seneca virus are difficult to distinguish from other vesicular diseases, especially the symptoms of foot-and-mouth disease. At present, the World Health Organization has not included the Seneca virus in the new edition of the “Manual of Diagnostic Tests and Vaccines for Terrestrial Animals” and this virus has not been classified in China. There is no commercial vaccine for this virus in the world, so as a farmer, we have to actively prevent this disease.

3. How to diagnose and prevent Seneca virus?
After collecting samples (blood, vesicular fluid, epithelial lesions, epithelial tissue, etc.), immunohistochemistry, RT-PCR, electron microscopy, etc. have been used for SVV research and diagnosis. Competitive enzyme-linked immunosorbent assay (ELISA) developed with monoclonal antibodies is more rapid and sensitive, and antibody detection for SVV is already very mature.
Because it is clinically impossible to distinguish Seneca virus from vesicular disease, foot-and-mouth disease, etc., take emergency prevention and control measures similar to foot-and-mouth disease before diagnosis, and fully inoculate conventional vaccine. The iodine preparation disinfectant can be disinfected in a 1:100 ratio, and the lime is used to disinfect the surrounding area. What’s more, do not forget to disinfect the personnel and vehicles entering and exiting pig farms.
Those provinces where the disease has occurred should pay more attention to strengthening preventive measures. Early detection, early reporting, and early disposal to prevent the spread of the epidemic.