Newcastle disease virus

Newcastle disease virus (NDV) is a highly contagious avian pathogen that affects a wide range of bird species, both domestic and wild. It is caused by the Newcastle disease virus, which belongs to the genus Avulavirus in the family Paramyxoviridae.

Virology

The Newcastle disease virus is an enveloped, single-stranded, negative-sense RNA virus. It has a spherical or pleomorphic shape and measures approximately 100-500 nm in diameter. The viral genome is about 15 kb in length and encodes six major proteins: nucleoprotein (NP), phosphoprotein (P), matrix protein (M), fusion protein (F), hemagglutinin-neuraminidase (HN), and large protein (L).

Transmission

NDV is primarily transmitted through direct contact with infected birds, their droppings, or respiratory secretions. It can also spread via contaminated feed, water, equipment, and clothing. The virus can survive for several weeks in the environment, particularly in cool and moist conditions.

Clinical Signs

The clinical signs of Newcastle disease vary depending on the virulence of the virus strain, the species of bird, and the age and immune status of the host. Symptoms can range from mild respiratory distress to severe systemic disease, including:

• Respiratory signs: coughing, sneezing, nasal discharge
• Nervous signs: tremors, paralysis, twisted necks
• Digestive signs: diarrhea
• Drop in egg production and quality

Diagnosis

Diagnosis of Newcastle disease is based on clinical signs, virus isolation, and serological tests. Laboratory confirmation is essential and involves techniques such as polymerase chain reaction (PCR), virus isolation in embryonated eggs, and hemagglutination inhibition (HI) tests.

Control and Prevention

Control of Newcastle disease involves a combination of biosecurity measures, vaccination, and surveillance. Vaccination is the most effective method to prevent the disease and is commonly used in poultry industries worldwide. Live attenuated and inactivated vaccines are available and are administered through various routes, including drinking water, spray, and injection.

Economic Impact

Newcastle disease has significant economic implications for the poultry industry due to high mortality rates, decreased productivity, and trade restrictions. Outbreaks can lead to substantial financial losses and impact food security.

Related Pages

• Newcastle disease
• Avulavirus
• Paramyxoviridae
• RNA virus
• Poultry

See Also

• Infectious bronchitis virus
• Avian influenza
• Marek's disease
• Fowlpox