blog about US Issues New Guidelines for Avian Flu Newcastle Disease Testing

The National Veterinary Services Laboratories (NVSL) has issued comprehensive new guidelines for sample collection to detect Avian Influenza (AI) and Newcastle Disease (ND), marking a significant advancement in avian disease surveillance and control efforts.

The updated guidelines (NVSL-WI-0023) replace all previous versions and establish standardized procedures for commercial poultry testing. All AI and ND testing must be conducted at laboratories approved by the National Animal Health Laboratory Network (NAHLN) or authorized by the National Poultry Improvement Plan (NPIP).

Non-negative test results require immediate submission to NVSL in Ames, Iowa for confirmatory testing. The guidelines include detailed tables outlining expected testing protocols and turnaround times to facilitate efficient coordination between stakeholders.

During disease outbreaks, NVSL emphasizes targeted sampling of specific bird populations:

• Recently deceased birds: These specimens typically contain high pathogen concentrations.
• Clinically affected birds: Samples from symptomatic birds provide direct evidence of active infection.
• Proximity sampling: When neither deceased nor symptomatic birds are available, sample birds near building air intakes or adjacent to affected areas.

For Foreign Animal Disease Investigations (FADI), the most rapid confirmation method involves submitting duplicate samples to both NAHLN laboratories and NVSL for parallel testing.

• Oropharyngeal (OP) swabs: Preferred for domestic poultry (chickens, turkeys)
• Cloacal (CL) swabs: Recommended for domestic waterfowl and wild birds

Swab pooling must adhere to strict criteria:

• Pool only specimens from the same species and production group
• Maintain separate pools for oropharyngeal and cloacal swabs
• For FADI investigations, collect minimum two pools of 11 swabs each

Brain Heart Infusion (BHI) medium is recommended for optimal viral preservation during transport. Alternative acceptable media include:

• Tris-buffered tryptose broth (TBTB)
• Nutrient broth (NB)
• Peptone broth (PB)

Dry swabs are strictly prohibited as they may inactivate AI and ND viruses within 24 hours.

Tissue samples should be pooled by anatomical system (respiratory, intestinal, reproductive). For serum collection:

• Select apparently healthy birds for routine surveillance
• Obtain samples from clinically affected birds for disease investigations
• Maintain samples at appropriate temperatures during transport

Key requirements for sample submission:

• Maintain cold chain during transport
• Store tubes upright to prevent leakage
• For priority shipments, use overnight delivery services
• Notify NVSL in advance via email (nvsl.ai.nd@usda.gov) for high-priority samples

These updated guidelines represent a significant advancement in avian disease detection capabilities, providing standardized protocols to enhance surveillance accuracy and outbreak response efficiency.