Newcastle Disease: Vaccines Aren’t Enough – UPM Expert
- This article discusses the persistent outbreaks of Newcastle Disease (ND) in Malaysia despite decades of vaccination efforts.
- * Vaccines reduce illness, but don't prevent infection: Similar to COVID-19, vaccination doesn't guarantee immunity.
- * Hidden Reservoirs: The virus circulates in various bird populations (backyard chickens, ducks, geese, migratory birds) without always causing symptoms, acting as ongoing sources of infection.
Summary of the Article: Newcastle Disease Outbreaks in Malaysia – A Complex Problem
This article discusses the persistent outbreaks of Newcastle Disease (ND) in Malaysia despite decades of vaccination efforts. The core issue isn’t simply vaccine failure, but a combination of viral evolution, weak biosecurity, and inadequate farm management.Here’s a breakdown of the key points:
1. Vaccine Effectiveness is Limited:
* Vaccines reduce illness, but don’t prevent infection: Similar to COVID-19, vaccination doesn’t guarantee immunity.
* Viral Diversity: NDV has a single serotype, but it’s genetically diverse with 21+ genotypes.Genotype VII is now dominant globally.
* Local Strain Divergence: The prevalent genotype VII.2 in Malaysia is substantially diffrent from older vaccine strains (LaSota, V1), reducing vaccine effectiveness.
* Maternal Antibodies: Vaccination in young chicks can be hindered by existing maternal antibodies.
2. Biosecurity & Farm Management are Crucial:
* Hidden Reservoirs: The virus circulates in various bird populations (backyard chickens, ducks, geese, migratory birds) without always causing symptoms, acting as ongoing sources of infection.
* Poor Sanitation: Insufficient waste management and sanitation allow the virus to persist on farms.
* Weak Immunity: Recurring outbreaks happen when immunity is low, even after vaccination.
* Husbandry Practices: Poor farm management allows the virus to spread from various sources.
3. Need for Re-evaluation & Improved Strategies:
* Revisit Vaccination Programs: Farmers should regularly evaluate their vaccination strategies, especially when outbreaks continue.
* Biosecurity is Key: Strengthening biosecurity measures is the most critical step in prevention.
* Consider Concurrent Infections: Other infections and immunosuppression can also contribute to outbreaks.
In essence, the article argues that simply vaccinating isn’t enough.A holistic approach focusing on robust biosecurity, understanding the evolving virus, and optimizing vaccination strategies is necesary to effectively control Newcastle Disease in Malaysia.