Corner of Knowledge

21.10.2026

Fowl plague

Newcastle Disease (Pseudofowl Plague)

Newcastle disease, also known as pseudofowl plague or Asiatic fowl plague, is a contagious and potentially fatal viral infection affecting all types of birds, including chickens, turkeys, and others. It is one of the most contagious poultry diseases and is caused by a virus belonging to the family Paramyxoviridae.

The infection can be so severe that some birds die without showing any signs of illness. Mortality in unvaccinated flocks may reach 100%. Deaths may also occur among vaccinated birds.

The virus is highly resistant in the environment. It can survive in poultry houses for five months in winter and one week in summer, and for more than two years in frozen poultry carcasses. In decomposing carcasses, it is inactivated within two to three weeks. It is rapidly destroyed by drying or exposure to sunlight.

Birds, including chickens, can contract Newcastle disease at any age. Domestic poultry, particularly chickens, are the most susceptible, while waterfowl are less susceptible.

How Does Newcastle Disease Spread?

The virus spreads through infected birds’ secretions and droppings, contaminated feed and water, the air, or direct contact. It may also spread through husbandry equipment, staff clothing and footwear, vehicles, and other means.

Wild birds, including ducks, geese, and pigeons, pose an additional risk and often act as natural reservoirs of the virus. The disease is frequently introduced into disease-free backyard flocks through contaminated hatching eggs.

The disease is particularly active in spring and autumn, reflecting seasonal factors.

Signs of Newcastle Disease

The disease spreads rapidly. Spread is slower when the main route of transmission is faecal–oral, particularly among caged birds.

Young birds are the most susceptible.

The incubation period ranges from two days to two weeks.

The disease usually follows an acute course, with the following signs:

  • High body temperature: 43–44°C;
  • Lethargy and reduced activity;
  • Swelling of the tissues around the eyes and neck;
  • Mucous discharge from the beak and closed eyes;
  • Difficult, open-mouth breathing;
  • Coughing and sneezing;
  • Depression, muscle tremors, and drooping wings;
  • Twisting of the neck backwards or to one side, and paralysis;
  • Greenish, watery diarrhoea;
  • Partial or complete cessation of egg production in laying hens;
  • High mortality;
  • Death within two to three days.

Post-Mortem Findings in Newcastle Disease

Pathological findings include:

  • Haemorrhages in the gastrointestinal mucosa and fibrinonecrotic intestinal lesions;
  • Respiratory lesions, including haemorrhagic lesions in the lungs, mucosal swelling, and haemorrhages;
  • Band-shaped haemorrhages in the mucosa of the proventriculus, which are highly characteristic of Newcastle disease;
  • Nervous system damage, including brain swelling and damage to nervous tissue, resulting in paralysis and impaired movement;
  • Lymphoid tissue involvement, including swelling of the spleen and other lymphoid organs. Lymphoid tissues are an important part of the immune system;
  • Changes in the skin and comb, including bluish discolouration of the comb, sometimes progressing towards black;
  • Other changes.

Prevention of Newcastle Disease

No specific treatment has been developed for this disease, making prevention essential.

The main goal of Newcastle disease prevention is to keep the infection from entering a healthy flock. The following measures are required:

  • Hatching egg control: use only eggs from healthy, verified sources. Disinfection of hatching eggs is essential.
  • Protection of flock health: promptly identify and isolate sick birds.
  • Staff hygiene: regularly disinfect work clothing and equipment.
  • Equipment cleanliness: regularly disinfect all technical equipment to help prevent the spread of the virus.
  • Feed and litter control: use only high-quality, safe feed to support immunity, and disinfect litter.
  • Timely vaccination: vaccination is the best means of protection against the disease. Live vaccines based on La Sota, H, and other strains are used.

All vaccines used against Newcastle disease can be divided into three main groups: inactivated vaccines, live vaccines attenuated by laboratory methods, and naturally attenuated vaccines.

It should also be noted that live vaccines are sensitive to handling and storage conditions and may be associated with reduced flock uniformity in young birds, lower meat yield in broilers, and reduced egg production in adult hens. The most effective vaccination method is individual intranasal administration.

The strength and duration of immunity in birds depend on feeding and husbandry conditions. During the three to five days before and after vaccination, supplements containing vitamins A, D, and B-group vitamins are necessary. Products that may be used for this purpose include AD3E Vitamin, Chiktonik, Ganaminovit, Multivit, and others.

When the disease is detected, the farm or backyard holding is declared affected by Newcastle disease and designated a quarantine zone.

Quarantine is lifted 30 days after the last case of Newcastle disease infection in the flock, and the farm buildings, structures, and surrounding grounds are disinfected.

These measures significantly reduce the risk of disease spread and help maintain a healthy environment for poultry.

Mikheil Chichakua
Veterinarian, Doctor of Biology
Association of Agro Experts

Fowl plague