NEWCASTLE DISEASE
News: Brazil has
declared an animal health emergency in the state of Rio Grande do Sul due to
the detection of Newcastle disease on a poultry farm.
- This led the Brazilian agriculture ministry to halt poultry exports
to certain countries as a preventive measure.
- The emergency declaration aims to contain and manage the outbreak
effectively
What’s in the News?
Newcastle Disease
- Newcastle disease (ND) is a highly contagious viral disease
affecting birds, especially poultry.
- It is caused by avian paramyxovirus serotype 1 (APMV-1), which has
multiple strains varying in virulence.
- The disease is found worldwide and can lead to significant economic
losses in the poultry industry.
- Newcastle disease is a minor zoonosis and can cause conjunctivitis
in humans who are in close contact with infected birds. However, it is not
considered a significant public health threat.
Types of Newcastle Disease Virus (NDV)
- Lentogenic (Mild) Strains: These strains cause mild respiratory symptoms and are often used
in live vaccines.
- Mesogenic (Moderate) Strains: These cause moderate respiratory and neurological symptoms but
typically result in low mortality.
- Velogenic (Virulent) Strains: These are further classified into viscerotropic (affecting the
intestines) and neurotropic (affecting the nervous system). They cause
severe disease with high mortality rates.
Transmission
- NDV is primarily transmitted through direct contact with infected
birds, their droppings, and respiratory secretions.
- The virus can spread via contaminated feed, water, equipment, and
human clothing.
- Wild birds and pigeons can act as reservoirs, maintaining the virus
in the environment and posing a risk to domestic poultry.
Clinical Signs
Symptoms of ND vary depending on the strain and can
include:
- Respiratory distress: gasping, coughing, sneezing.
- Nervous signs: tremors, twisted necks, paralysis.
- Digestive issues: greenish diarrhea.
- Sudden death without prior symptoms.
- Decreased egg production and quality in laying hens
Prevention and Control
- Biosecurity: Implementing strict biosecurity measures to prevent the
introduction and spread of the virus. This includes disinfecting
equipment, restricting access to poultry farms, and isolating new or
returning birds for at least 30 days.
- Vaccination: Prophylactic vaccination is widely practiced, especially in
regions with a high incidence of ND. Live attenuated and inactivated
vaccines are commonly used.
- Surveillance and Reporting: Continuous monitoring and immediate reporting of outbreaks to
veterinary authorities are crucial for controlling the disease spread.
Geographical Distribution
- ND is present worldwide, with varying levels of control in
different regions.
- It is endemic in parts of Africa, Asia, and South America, while
countries like the United States, Canada, and some European nations have
achieved better control over the disease.
Source: https://www.reuters.com/world/americas/brazil-declares-animal-health-emergency-rio-grande-do-sul-after-newcastle-2024-07-19/