Which method is least likely used for diagnosing African Swine Fever?

The method of visual inspection is least likely to be used for diagnosing African Swine Fever (ASF) because this disease presents with symptoms that can be non-specific and similar to other swine diseases. Visual inspection may allow for the identification of some clinical signs, such as fever, skin lesions, or sudden death, but these signs alone cannot confirm ASF without laboratory testing.

In contrast, diagnostic methods such as PCR (Polymerase Chain Reaction) are specifically designed to detect the genetic material of the ASF virus, providing a highly accurate confirmation of the disease. Other methods, like DIF (Direct Immunofluorescence) tests and HAD (Hemadsorption) tests, are also useful in distinguishing ASF, thanks to their ability to identify viral agents or their effects more reliably than visual observation can. Thus, relying solely on visual inspection for the diagnosis of ASF is inadequate compared to the more reliable laboratory techniques available.