Summary of bovine viral diarrhea virus (BVDV)

Pathogenic Characteristics

Bovine viral diarrhea virus (Bovine viral diarrhea virus comes, BVDV) wen virus genera belong to yellow virus, is a single strands of capsular membrane is chain RNA virus, the virus particle spherical or ellipsoidal, about 20 ~ 60 nm in diameter. BVDV is sensitive to the chemical reagents such as pancreatic enzymes and chloroform, under the condition of 56 ℃ are quickly inactivated, and better tolerability of alkaline environment, can be in bovine kidney, testis, turbinate, extend the trachea and lung cells proliferation.

epidemic

BVDV widely popular around the world, including Europe, North America, South America and Asia, and many other countries and regions, caused huge economic losses to the local animal husbandry. First discovered in the United States since 1946, BVDV were reported around the world. In China, reported for the first time since 1980, BVDV have several provinces across the country have been isolated, and popular in the herd.

Route of transmission

BVDV mainly spread through the digestive tract and respiratory tract, can also be transmitted through the placenta vertical. BVDV infection of animals, particularly persistent infection (Persistently Infected, PI) cattle, is the main source for the spread of the disease. Virus can through discharge and waste discharge, animals and other animals. In addition, the blood-sucking insects can also be a medium.

Clinical signs and symptoms

In many BVDV infection, clinical symptoms, including fever, diarrhea, oral mucosal erosion, leukopenia, etc. For acute infection, the body temperature of infected cattle can reach 40 ~ 42℃, the spirit is depressed, the appetite is decreased, the diarrhea is severe, and sometimes blood and mucus can be seen in the feces. Chronic infections may only showed mild symptoms, such as intermittent diarrhea and weight loss. Pregnant cows if in the first trimester of pregnancy, infection may cause abortion, stillbirth, or output malformation fetus. Newborn calves may exhibit neurological symptoms, such as ataxia, opisthotonos.

Pathological changes

BVDV infection caused by pathological changes mainly reflects in the digestive tract mucosal erosion and necrosis, such as oral cavity, esophagus, rumen and other parts. In serious cases, hemorrhage, necrosis and ulcer formation. For chronic infections, only mild mucosal inflammation and erosion may be seen. Under special circumstances, such as infection of pregnant cows, fetal cerebellar hypoplasia or other congenital abnormalities may occur.

Diagnostic methods

The diagnosis of BVDV mainly depends on clinical symptoms, epidemiological investigation, serological test and pathogen detection. Commonly used serological tests including neutralization test, immunodiffusion test, fluorescent immune antibody test, etc. Etiology detection can through electronic microscope, rt-pcr, nucleic acid probe hybridization test method. Can from cattle in virus isolation, identification of blood, urine, nasal secretions samples isolated viruses, and represented by cell culture.

Prevention and control measures

At present, in view of BVDV there is no specific drug treatment, vaccination is the main measures and strengthen the veterinary health. Vaccines, live attenuated and inactivated vaccine for prevention, but their protection effect and use safety is still in the study. Veterinary hygiene, advice for environmental management, such as to cleaning and disinfection of the barn, on a regular basis to ensure the breeding density is reasonable, avoid overcrowding. In addition, cattle with suspected diseases should be isolated in time and the circulation of diseased materials should be strictly controlled to prevent the spread of the virus.

conclusion

Above all, BVDV is a major threat to the global cattle industry of pathogen, its popular widely, transmission diversity, complex clinical symptoms, and lack of effective treatments for the present. Therefore, cattle farmers in various countries should be vigilant in their daily management and take comprehensive prevention and control measures to reduce the potential impact of BVDV on animal husbandry.