Which diagnostic test is least commonly associated with ASF?

The least commonly associated diagnostic test for African Swine Fever (ASF) is ultrasound imaging. ASF is a viral disease that primarily affects domestic pigs and is characterized by high mortality rates. Diagnosing ASF typically involves laboratory-based methods that can confirm the presence of the virus or its genetic material.

Virus isolation is a key method for definitively diagnosing ASF, as it involves growing the virus from samples taken from infected animals, allowing for direct detection of the pathogen. Immunohistochemistry is utilized to identify viral antigens in tissues, providing crucial histological evidence of infection. Polymerase Chain Reaction (PCR) is a highly sensitive molecular technique that detects viral DNA, making it one of the most reliable methods for diagnosing ASF quickly and accurately.

In contrast, ultrasound imaging is not conventionally used for diagnosing ASF. While ultrasound can be useful for assessing structural changes and organ function in veterinary medicine, it does not provide specific information about viral infections like ASF. Therefore, among the listed options, ultrasound imaging is the least relevant diagnostic test for this disease.