1. Poultry Industry in Iran

Iran has one of the Middle East’s largest and most structurally advanced poultry industries. It serves as a vital pillar of the country’s food security, especially as inflation and macroeconomic pressures have drastically decreased the purchasing power of red meat, causing consumers to rely almost exclusively on poultry protein.

• Production and Population Dynamics: There are more over 20,000 industrial broiler farms, significant commercial layer operations, and highly integrated parent stock facilities in the country’s commercial sector. The industry generates more than one million metric tons of table eggs and between 2.2 and 2.5 million metric tons of poultry meat per year at its maximum operational capability.
  • Meat Consumption Per Capita: The main animal protein in Iranian diets is now unquestionably chicken meat. Official estimates of the annual per capita consumption of poultry meat range from 28.5 to 31.25 kg.
• Egg Consumption Per Capita: Depending on the socioeconomic characteristics of particular provinces (e.g., more direct consumption in major cities like Tehran), egg consumption is predicted to be between 160 and 198 eggs per person annually.

2. Newcastle Disease Brief

Early in the 1950s, the illness was first formally identified and documented in the nation. Since it was first discovered, the virus has evolved from an epidemic threat to a firmly established, hyper-endemic infection that requires Iran’s commercial sector to adhere to some of the world’s most stringent and ongoing vaccination protocols. NDV remains one of the most destructive viral pathogens affecting the poultry industry globally.
The three main pathotypes of Newcastle Disease Virus (NDV) strains in birds are lentogenic (low virulence, mild/no symptoms), mesogenic (moderate virulence), and velogenic (very pathogenic, causing severe respiratory/nervous manifestations and significant mortality).

• Etiology: The disease is caused by virulent strains of Avian Orthoavulavirus 1, family Paramyxoviridae (formerly known as Avian Paramyxovirus 1 or APMV-1). It is an enveloped, single-stranded, negative-sense RNA virus.
• Transmission: The virus spreads via inhalation or ingestion of contaminated secretions. Migratory birds act to introduce new strains into local poultry populations.
• Clinical Signs: Infected birds shows severe respiratory distress, greenish diarrhea, and neurological signs, as torticollis and leg paralysis.
• Pathology: Postmortem examinations typically shows proventricular, cecal tonsils, and intestinal lymphoid patches hemorrhages, in addition to catarrhal tracheitis.
  The amino acid motif at the viral Fusion (F) protein’s cleavage site is the main factor that determines NDV pathogenicity.

3. Most Prevalent Genotypes and Recent Outbreaks

Over the past 20 years, there has been a significant evolution in the molecular epidemiology of NDV in Iran. A new dominant lineage has entirely overshadowed older lineages and subgenotypes that have circulated historically, such as XIII.2.1, which was discovered in backyard flocks in 2010.

• The Dominance of Genotype VII: Class II, subgenotype VII.1.1 (formerly known as VIId) currently dominates Iran’s epidemiological landscape. The formation of a well-supported monophyletic group VII.1.1 is confirmed by maximum likelihood and Bayesian phylogenetic analyses of the Fusion (F) and Hemagglutinin-Neuraminidase (HN) genes between 2017 and 2024. This suggests that the virus has been evolving independently, quickly, and continuously inside Iran’s chicken population since its introduction.
• Recent Outbreaks in Vaccinated Flocks: There have been serious epizootics recently in key poultry centers including Ahvaz, Khorasan, and Mazandaran. Commercially vaccinated broiler and layer flocks are often affected by outbreaks that manifest as velogenic viscerotropic ND. Acute respiratory distress, severe hemorrhagic lesions in the proventriculus, and mortality rates between 40% and 100% are among the clinical symptoms.

4. Control, Recommendations, and Vaccination

Antigenic mismatch is the main issue Iranian poultry veterinarians are dealing with. The traditional Genotype II live lentogenic vaccines (such as LaSota, Hitchner B1, and Clone 30) are an essential component of the commercial sector. Genotype II vaccinations are phylogenetically distinct from the circulating Genotype VII field strains, despite the fact that they prevent 100% death. As a result, they are unable to fully neutralize the virus, which enables vaccinated birds to develop into subclinical carriers that significantly release virulent virus into the environment.

Transition to Genotype-Matched Vaccines: To halt environmental viral shedding and break the transmission cycle, vaccination protocols must incorporate inactivated, homologous oil-emulsion vaccines derived directly from local Genotype VII field strains.

Strict Biosecurity: Physical biosecurity needs to be enhanced because NDV subgenotype VII is extremely resilient in the environment. In order to stop mechanical transmission from feral pigeons and backyard poultry, which serve as unmonitored viral reservoirs, commercial buildings must be bird-proofed.

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https://www.vaccinevalley.com/product-category/poultry/