In the United States, which laboratory is able to confirm a positive diagnosis of an exotic disease in the index case?

• A. The National Animal Health Laboratory Network (NAHLN) laboratories
• B. The OIE Laboratories in Paris, France
• C. The National Veterinary Services Laboratories (NVSL)
• D. Certified Veterinary Diagnostic Laboratories (CVDL)

Answer: (C)

The main idea is that official confirmation of an exotic disease in a suspected US index case comes from the National Veterinary Services Laboratories. NVSL is the USDA APHIS reference laboratory responsible for definitive, confirmatory testing and issuing official diagnoses for animal diseases at the national level. It coordinates with the NAHLN network (which does screening and surveillance at state and federal levels) and provides the authoritative confirmation needed for regulatory actions and international reporting.

Local and state veterinary diagnostic labs can perform initial tests, but their results aren’t the final national confirmation for exotic diseases. International reference labs exist (such as OIE labs in Paris), but a definitive confirmation for a US case must come from NVSL to be officially recognized within the United States and for reporting purposes. Certified Veterinary Diagnostic Laboratories perform many diagnostics as well, but they do not hold the official national confirmatory authority for exotic diseases; they would typically send confirmatory specimens to NVSL.