African Swine Fever: Diagnostic Preparedness, Surveillance and Response Discussion with USDA

What is the status of response planning for African swine fever?

USDA Animal Plant and Health Inspection Service (APHIS) has posted a disease response strategy for ASF on its FAD PReP website. States and the pork industry use this information to do state-specific planning. USDA has also committed to work with the industry to develop and host an ASF- specific exercise in 2019 to test key response functions necessary for successful ASF management and containment. Exercise participants will include pork producers, swine veterinarians, packer and processors, and allied industry. Invitations to participate will be sent to Canada and Mexico.

What is the status of laboratory capacity to test for African swine fever should we have an outbreak in the United States?

APHIS has approved 11 National Animal Health Laboratory Network (NAHLN) laboratories to test for ASF. At the current capacity, 6,500 PCR samples could be run per day. Capacity could be increased to 8000 samples per day with additional proficiency tested staffing. USDA’s Center for Epidemiology and Animal Health is determining the sample size needed for testing if we experience an outbreak.

USDA has identified another 22 laboratories that would like to add ASF to their approved tests and competencies. These laboratories could potentially add capacity for another 9,000 tests per day.

The current approved sample type for ASF testing in NAHLN laboratories is only whole blood. However, as of October 1, tonsil, which is a validated sample for ASF testing at USDA’s Foreign Animal Disease Diagnostic Laboratory (FADDL), will be approved for use in NAHLN labs for foreign animal disease investigations. USDA is in the process of validating swine oral fluids for ASF testing. Steps in the validation process for use in an outbreak include evaluation of positive samples from experimentally infected animals and testing of field outbreak samples. VS expects to complete the first step by March 2019 and determine the analytical sensitivity and specificity of the assay, and subsequently guide deployment of the assay in the case of a US outbreak. At industry’s request, USDA is evaluating costs and utility of adding spleen as an approved sample for ASF testing in NAHLN laboratories.

What is the status of African swine fever surveillance in the United States?

Currently, there is only a passive surveillance system for ASF early detection that relies on producers or veterinarians reporting suspected cases of ASF to state or federal animal health officials. USDA piloted an active ASF program using the approved sample, whole blood, which was similar to the classical swine fever program. USDA is modeling surveillance needs, including development of a revised case definition for sick pigs and identification of the best surveillance streams for early disease detection. USDA has agreed to start testing tonsils from case compatible submissions in the NAHLN for foreign animal disease investigations effective October 1, 2018. We are developing estimated costs of adding additional samples, such as spleen, to determine budget requirements for adding additional samples. USDA is also exploring testing of case compatible samples taken from sick pigs observed at licensed plate waste feeding facilities during their regular inspections.

Can USDA sign regionalization agreements with trading partners in advance of an outbreak?

USDA and Canada have signed an agreement to recognize their respective regionalization plans in the case of a foreign animal disease outbreak. USDA will consider working with other trading partners on more proactive agreements, but the process is resource intensive and will take considerable time. There is additional complexity with these negotiations since there has not been an outbreak of a foreign animal disease in U.S. swine in decades. As a result, U.S. capabilities to regionalize for swine diseases has not been demonstrated.

How will USDA dispose of animals culled during an outbreak?

Each state will need to develop their own disposal plan. Producers should work with their State Animal Health Official’s office to consider site specific disposal plans.