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Newcastle Disease*


Since the first reports of Newcastle disease (ND) in 1926, this viral disease has become widespread in many countries, threatening the poultry industry’s flocks with respiratory, visceral, and neurologic clinical signs as well as poor performance, especially in egg production. The virus has numerous serotypes and strains ranging from low to high virulence, with varying symptoms and rates of mortality. It causes serious economic losses to poultry producers and breeders worldwide, making disease control a high priority in the industry.


Disease Management Approaches

Newcastle disease cannot be treated post-infection, so prophylactic vaccination is critical to protect poultry health and, in turn, productivity, as well as help control the spread of this contagious virus. It is transmitted through direct contact with feces and respiratory discharges and can persist in certain environments, so hygiene management is also key. The disease has been successfully eradicated in some countries, a status maintained through well-established vaccination protocols, biosecurity, and trade restrictions. 

To account for pathotype diversity, a wide variety of vaccine types are available, including live, inactivated, and vectored, with options for both hatchery and field administration. Developing a Newcastle vaccination program is complex—there is no "one size fits all" solution. Rather, choosing the right vaccines requires carefully considering a multitude of factors: local epidemiology, maternal antibody timing, labor, cost, regulations, and more.

Accurate diagnosis and strain identification are an important first step. Accounting for strain virulence, vaccine selection then involves finding the optimal balance of efficacy and safety. Because the disease particularly affects egg production, and thus longer-lived layer and breeder birds, duration of immunity is also an important factor, and revaccination may be necessary. Ongoing monitoring allows for adapting the program to changing conditions.


Merial’s Solutions**

Over the years Merial has developed a deep and comprehensive portfolio of products** to address the complexities of effective Newcastle disease vaccination.* Our ND solutions include the following brands:

  •  AVINEW®, a live attenuated virus of Newcastle disease, offered in multiple regions (and also available in some markets** in  NeO effervescent tablet form)
  •  GALLIMUNE  range, our multi-region line of inactivated vaccines, many of which are combination products with other diseases
  •  TROVAC NDV, a fowl pox vector vaccine (marketed in the U.S.)
  •   A large selection of other vaccines (some for ND alone, some combination products) for specific strain and regional needs

Merial's live ND vaccines are highly regarded for quality, but most important is the breadth of our portfolio, allowing us to offer our clients the best solution for their particular situation. Brand and product availability vary across markets, but we are always evolving our offerings to address new challenges and changing epidemiologic conditions.

Our customer solutions also include the expertise of our Veterinary Services teams, who understand the complexities of ND vaccination. Leveraging our deep knowledge of regional epidemiologies and scientific evidence on vaccine performance, we develop customized vaccination programs for each customer's current field challenge and ongoing conditions. And Merial's Vaccination Technologies & Services (VTS) group provides not only the necessary equipment and training for successful vaccination, but also on-site audits and consulting on biosecurity, hygiene practices, and quality control to help optimize any ND control program.


More About Newcastle Disease*

Named after the city of Newcastle, England, one of its earliest sites of identification in 1926, the Newcastle disease virus is endemic to many regions of the world. It is part of a genus of avian paramyxoviruses and infects primarily chickens but also other avian species such as turkeys, with younger birds most susceptible.

Once birds are infected, onset of disease signs tends to be rapid and fast-spreading. Clinical manifestations vary depending on viral strain, which can be broadly grouped into four categories (listed here from least to most virulent) :






  • Non-virulent
  • Very mild clinical signs and negligible mortality
  • Most often used in vaccines




  • Intermediate virulence
  • Low mortality
  • Reduced egg production/quality
  • Mild respiratory symptoms (primarily coughing)
  • Sometimes used in vaccines





  • Highly contagious
  • High mortality
  • Reduced egg production/quality
  • Neurologic signs, including limb/wing paralysis, twisted neck, tremors, spasms, circling
  • Usually severe respiratory signs, including coughing, sneezing, gasping, and labored breathing

   Viscerotropic        velogenic


  • Highly contagious
  • Highest rates of mortality, up to 90-100%
  • Sudden death
  • Reduced egg production/quality
  • Most severe respiratory signs, including coughing, sneezing, gasping, and labored breathing
  • Diarrhea
  • Lethargy & loss of appetite
  • Hemorrhage in the viscerae, like proventriculus or intestines



These categories are not fixed, and there may be some overlap in strain classification. In addition, some ND categorizations include asymptomatic strains.


*Merial produces and markets several vaccines against Newcastle disease. However, be aware that NOT all aspects of the disease mentioned on this page are addressed by a vaccine. Always consult the product label for exact vaccine indications.

**Many of Merial’s avian vaccines are only marketed and available in certain countries, sometimes under different trade names. Speak to your Merial representative or contact us to find out what’s available in your region.


To find out exactly which Merial avian products and vaccination equipment options are available in your region, talk to your Merial representative or contact us now.

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