By David Fairfield, Senior Vice President, Feed
The U.S. Department of Agriculture (USDA) on March 25 announced that unpasteurized, clinical samples of milk from sick cattle collected from two dairy farms in Kansas and one in Texas, as well as an oropharyngeal swab from another dairy in Texas, have tested positive for highly pathogenic avian influenza (HPAI). USDA states that based on findings from Texas, the detections appear to have been introduced by wild birds.
These incidents represent the first time HPAI has been identified as affecting dairy cattle. On March 20, the Minnesota Board of Animal Health announced that HPAI was detected in a goat on a Minnesota farm where an outbreak had recently been detected in poultry. The occurrence of HPAI in the goat was the first U.S. detection of HPAI in livestock.
Federal and state agencies are conducting additional testing for HPAI, as well as viral genome sequencing, to better understand these situations, including characterization of the HPAI strain or strains associated with these detections. Significantly, initial testing by the National Veterinary Services Laboratories has not found changes to the virus that would make it more transmissible to humans, which would indicate that the current risk to the public remains low.
Further, USDA states, at this stage, there is no concern about the safety of the commercial milk supply or that this circumstance poses a risk to consumer health. Dairies are required to send only milk from healthy animals into processing for human consumption; milk from impacted animals is being diverted or destroyed so that it does not enter the food supply. In addition, pasteurization has continually proven to inactivate bacteria and viruses, like influenza, in milk. Pasteurization is required for any milk entering interstate commerce.
HPAI is an extremely infectious influenza virus that is often fatal to poultry, and can spread quickly by direct, bird-to-bird contact. The virus can also spread indirectly, such as when birds come in contact with contaminated surfaces or materials. Migratory waterfowl (including wild ducks and geese) and the movement of poultry, poultry equipment, vehicles and people are other potential sources for spreading the disease.
When an outbreak occurs, USDA’s Animal and Plant Health Inspection Service (APHIS) works closely with animal health officials in the state on a joint incident response. Key components of the response include movement standstill orders, quarantine and area/zone designations, and depopulation of birds to prevent the spread of the disease.
Grain and feed facilities potentially can be affected when an outbreak occurs. Facilities associated with an affected farm likely will be expected to obtain a movement permit and maintain records related to movements of delivery trucks, and other service vehicles and personnel. As a resource to members, NGFA has made available guidance that provides information on animal disease biosecurity considerations and preparedness and response issues.
In addition, USDA has made available a variety of resources related to prevention of HPAI. NGFA encourages grain and feed facilities to implement biosecurity practices that are effective and appropriate for their operations.