Summary of porcine epidemic diarrhea virus (PEDV)

Pathogenic characteristics

Porcine epidemic diarrhea virus (PEDV) belong to the coronavirus family, approximate spherical virus form, between 95-190 nm in diameter, average diameter of about 130 nm. Virus surface has a petal shaped fiber, the fiber spacing is bigger and radiated distribution. PEDV in the nucleic acid for linear single strands of RNA is chain, genome size is about 28 KB, S, N, P, M four main structural gene and ORF3 affiliated gene. Genome 5 'end cap structure, 3' end with the PolyA, Kozak sequence. Viruses can only in small intestinal epithelial cell proliferation, and on the thermal instability, is readily inactivated by ether and chloroform.

epidemic

PEDV found in Britain for the first time since 1971, has been popular in many countries and regions in, caused huge economic losses to the global pig industry. Especially in the Asian region, PEDV caused piglet mortality is higher, in Europe, PEDV large day age pig diarrhea, caused by the main damage is relatively small. In recent years, the majority of provinces and autonomous regions in China are a popular PEDV reported, and the epidemic area and popular intensity has a tendency to continuously expand and strengthen.

Route of transmission

PEDV mainly spread through the digestive tract, concrete means including dung -- the mouth travels, the virus can through the infected pig feces or natural infection of pollutants through the mouth way. In addition, the virus can spread through the respiratory tract, nasal secretions of infected pigs can get rid of the virus, it could be a PEDV pigs or adjacent in the same circle one of the ways to spread in the herd of swine.

clinical signs and symptoms

PEDV infection after the main clinical symptoms included vomiting, diarrhea, dehydration, sport stiffness etc. Pigs are susceptible of all ages, but the incidence of nursing piglets can amount to 100%, with a high mortality rate, especially in piglets under 1 weeks. The symptoms of swine relatively light, usually only vomiting and anorexia.

Pathological changes

PEDV infection causes small intestinal villus epithelial cell necrosis, fall off, intestinal villus shortened, intestinal wall thinning. In mesenteric lymph nodes, blood stasis hemorrhages, small intestinal villus epithelial cells, intestinal cells, fossae parts, small intestinal villus lamina propria and mesenteric lymph nodes will appear strong positive expression of PEDV.

Diagnostic methods

The method of diagnosis of PEDV infection including immunofluorescence, ELISA, neutralization test, etc. These methods can be used to detect tissue samples of sick pigs or intestinal contents of PEDV specific antigen, so as to make a diagnosis.

Prevention and control measures

Vaccination is the main method to prevent PEDV infection, the current commonly used vaccine including weak poison vaccine and inactivated vaccines. But new vaccines such as mRNA vaccine is developing, and shows good immune effect and neutralizing ability. Once the onset, isolation, disinfection, heat preservation measures should be taken, and the sick pigs group of symptomatic treatment, such as rehydration, antibiotics control secondary infections.

conclusion

PEDV is a major threat to the global pig industry, is highly infectious and pathogenicity. Virus is spread through various channels, clinical symptoms and varied, but mainly for acute gastroenteritis, diarrhea and dehydration. Pathological changes mainly concentrated in the gut, and the virus is sensitive to heat, easy to common disinfectants inactivated. There are a variety of diagnostic methods can be used for the detection of PEDV, and vaccination strategy is the key to prevent the disease. With the deepening of the research on PEDV, new vaccines and treatments are also constantly developing.