Avian influenza lessons for African swine fever

Recent avian influenza outbreaks demonstrate what a full-scale animal disease response looks like

29 April 2024

4 minute read

By: Chris Wright

North America

Foreign animal disease (FAD) planning has been a priority for Minnesota since the early 2000s. The 2015 highly pathogenic avian influenza (HPAI) outbreak incident gave state leaders a baseline for what a full-scale animal disease response would look like. This started a series of preparedness steps both internally and with swine stakeholders, said Lucia Hunt, Director, Office of Emergency Preparedness and Response, Minnesota Department of Agriculture.

In 2018, a major outbreak of African swine fever (ASF) in Asia prompted a closer look at how the swine industry could prepare for and maintain resilience throughout a disease event. The 2020 Covid supply chain disruption of swine allowed for the exercise of mass carcass disposal, which motivated planners to face the threat in more concrete terms, Hunt said during the 2024 American Association of Swine Veterinarians conference.

Response partners

Government regulators alone cannot be the response entity without veterinarians, company operations managers, processors and researchers. For HPAI, a Poultry Emergency Disease Management Committee was formed, which Minnesota duplicated for swine in 2019 to explore the various aspects of an in-depth response, Hunt said.

Metrics

USDA Veterinary Services has identified 23 critical activities for a successful response that guides their preparation goals. Some of these competencies require veterinary expertise, while other competencies rely on the experience of emergency managers. Together, they build a well-rounded response, she noted.

Critical incident activities are:

Etiology and ecology
Case definitions
Surveillance
Diagnostics
Epidemiological investigation and tracing
Information management
Communication
Health and safety and personal protective equipment
Biosecurity
Quarantine and movement control
Continuity of business
Regionalization for international trade
Mass depopulation and euthanasia
Disposal
Cleaning and disinfection
Vaccination
National veterinary stockpile
Wildlife management and vector control
Animal welfare
Modeling and assessment tool
Appraisal and compensation
Finance
National response framework and national incident management system

Hunt pointed out that although not all these categories have clear analogs, lessons learned in these categories from the HPAI incidents have been translated to a potential ASF incident.

For example, poultry depopulation events where the case manager, site manager, contractor crews, farm workers and companies all had different ideas of how to proceed efficiently drove the creation of procedures of on-site hierarchy and communication, she explained.

Incident management

State level operations begin with a trained and experienced Incident Management Team (IMT). Immediate action on diagnosis notification, case management, depopulation and disposal, and finance sets up an IMT for a robust response. Offering just-in-time training for personnel, preparing vendors in the state system, and setting up a physical incident command post for responders are a second tier of response actions as the incident ramps up.

Finally, stakeholder involvement, small flock/herd outreach, and multi-agency coordinating groups are established to ensure a communications flow from the incident to other invested parties.

While individual processes and activities in the HPAI response look different from the lens of the swine industry, and the scale, equipment and methods may change, the general principles and organization will stay much the same, she said.

Keeping the swine industry abreast of HPAI activities allows for an understanding of the structure they will be working within during a disease event.

Biosecurity ideas from the egg industry

Craig Rowles, DVM, Iowa, has worked in both the swine and egg layer industries for more than 30 years. During the 2024 American Association of Swine Veterinarians conference, he noted that the laying hen industry shares many similar risks with the pork industry regarding the need to prevent the introduction of disease agents onto farm operations.

HPAI is a foreign animal disease that entered the commercial poultry industry in both 2015 and 2022, resulting in millions of birds that required depopulation and disposal. The primary method of preventing this risk is to invest time, money and effort into biosecurity measures, he said.

To prevent an HPAI outbreak, it is the responsibility of everyone involved to keep poultry flocks from becoming infected by focusing on biosecurity they can control on their premises. Biosecurity approaches include both structural and operational components, Rowles explained.

Structural biosecurity refers to the physical construction, design, and maintenance of a facility to prevent entry of disease vectors and facilitate compliance with operational biosecurity.
Operational biosecurity involves risk assessment and mitigation of risk through management practices, including implementation of and compliance with standard operating procedures (SOPs) designed to prevent the introduction of the AI virus onto a premises.

Line of separation

The basic principles for biosecurity remain the same in layers as pigs. The most important aspect of those principles is to maintain the line of separation (LOS). The lowest hanging fruit is to prevent disease from being “walked” into a farm. HPAI can be shed in several ways, but the primary method is contaminated fecal material, he said.

With migrating wild birds flying overhead every fall and spring, the ground outside the farm buildings must always be considered contaminated. Structural and operational plans are directed at respecting the LOS, Rowles emphasized.

An important difference between the swine and egg layer industries is the size and scope of the operations. From a structural viewpoint, egg producers have invested heavily in facilities that can accommodate shower in/shower out facilities. In addition, egg producers have developed operation protocols that facilitate the line of separation, Rowles concluded.