Newcastle Disease

 
Why in News?
Newcastle Disease (ND) is a highly contagious and often fatal viral disease affecting birds, particularly domestic poultry. It is currently making headlines due to a significant and rapid spread across Europe, leading to the culling of millions of birds. 
 
Disease Overview

• Caused by virulent strains of avian paramyxovirus type 1 (APMV-1), part of the Paramyxoviridae family.

• Highly contagious; spreads via direct contact, aerosols, contaminated feed/equipment, or wild birds.

• Affects over 250 bird species, domestic and wild; poultry (chickens, turkeys) most severely impacted.

Forms and Severity

• Lentogenic (mild): Common, low mortality, mainly respiratory issues.

• Mesogenic (moderate): Higher virulence, affects egg production.

• Velogenic (very virulent, or exotic ND): Fatal, up to 100% mortality in chickens; systemic with respiratory, nervous, and digestive signs.

Symptoms

• Respiratory: Sneezing, coughing, nasal discharge, gasping.

• Nervous: Tremors, head twisting, paralysis, circling.

• Digestive: Greenish diarrhea, lack of appetite.

• Other: Sudden death, ruffled feathers, swollen eyes/head, drop in egg production.

Transmission and Impact

• Incubation: 2-15 days, typically 5-6.

• Not a major human health risk; rare mild conjunctivitis in handlers without PPE.

• Economic devastation via mass culling; reportable to WOAH in highly pathogenic forms.

Prevention and Control

• Vaccination: Live or inactivated vaccines reduce clinical signs but not infection.

• Biosecurity: Quarantine, disinfection, restrict wild bird contact.

• Diagnosis: Lab confirmation essential (similar to avian influenza).

• Treatment: None; supportive care only; slaughter in outbreaks.