To discuss the history of Newcastle Disease, we must go back to 1898 in North Scotland, where a chicken merchant closed his shop for the night. Upon reopening the next day, he shockingly found that all his chickens had died, and no one had an answer as to why. The mystery persisted until 1926 in the city of Java, Indonesia, where chickens began dying under mysterious circumstances. At that time, many chickens in Java were dying from Influenza, leading to assumptions that Influenza was to blame for these mysterious deaths. However, in 1927, in the small English town of Newcastle, a similar wave of chicken deaths occurred. Dr. T.M. Doyle then established that this was not Influenza but a new virus. The disease was named Newcastle Disease after the town. By 1950, this virus had spread to India, and in the Indian subcontinent, it was named Ranikhet. To this day, among all identified poultry diseases, Newcastle Disease, or Ranikhet, is considered the most deadly and formidable because it has a mortality rate of nearly 100%. However, with certain precautions, this mortality rate can potentially be reduced to 30%.

Newcastle Disease

Disease introduction

Group : Group V ((-)ssRNA

Order : Mononegavirales

Family : Paramyxoviridae

Species : Newcastle disease virus (NDV)

This virus spreads from one place to another through the air. In our country like (India, Bangaldesh, Pakistan) , during the summer, the temperature remains at a level where the virus stays inactive. However, as soon as the temperature drops, the virus becomes active. The virus causes a zoonotic disease, meaning it can transfer from domestic animals and birds to humans. Nevertheless, the virus does not have a significant impact on the human body; it may occasionally cause mild watering and redness of the eyes.

The severity of this virus can be categorized into three types:

Lentogenic: In this case, there are generally no symptoms, but young chickens may exhibit mild respiratory distress.

Mesogenic: This form has moderate severity and is often referred to as the "Asiatic form" because it is more prevalent in Asia. It primarily causes respiratory distress in chickens along with other symptoms, particularly affecting the nervous system (Torticollis). The mortality rate can be around 20% if vaccinations are properly administered.

Velogenic: This is the most severe form of the virus, with a mortality rate of up to 90% and a sickness rate of 100%.

Severity

Transformation

This virus can be transmitted in various ways, but primarily it occurs through two mechanisms:

Direct transmission:

In this scenario, when an infected chicken comes into contact with a healthy chicken, the healthy chicken becomes infected due to the exposure. The virus spreads as the sick chicken exhibits symptoms such as nasal discharge and diarrhea, which can be inhaled by the healthy chicken through respiration.

Indirect transmission:

• Through contaminated litter and unsterilized equipment.

• The virus can also be introduced into the shed through open-market feed if good quality, company-manufactured feed is not used.

• Lack of adequate biosecurity measures can also lead to transmission via the clothing and footwear of farm workers and visitors.

Prevention

Since there is no cure for this disease, prevention is the only treatment. Before understanding preventive measures, it is important to note that this disease is a major cause of loss in the poultry business, and considerable amounts of money are spent on medication due to this disease. This not only increases farm expenses but also prevents chickens from reaching their desired weight due to the excessive use of antibiotics. Therefore, preventive measures are considered the key to success in a poultry farm. Let’s learn about the preventive measures for Ranikhet disease.

• Firstly, biosecurity must be ensured on the farm. A well-maintained biosecurity system can reduce diseases by up to 80% on a farm. However, in our country, most farmers do not follow biosecurity protocols properly.

• New chickens brought from the market or another farm should not be placed immediately with the existing flock. The new chickens should be isolated for some days to ensure that if they are carrying any disease, it does not spread to the rest of the flock.

• The farm must have control systems for maintaining necessary temperature and humidity.

• Visitors should be minimized as much as possible. If visitors must enter, their clothing and shoes should be disinfected.

• It is better not to rear chickens of different ages in the same shed.

• Regular cleaning and disinfection of the litter must be done.

• Chickens should be fed good quality, commercial feed instead of open-market feed.