Protecting Animal Health through Disease Detection, Prevention, and Control

Protecting Animal Health through Disease Detection, Prevention, and Control

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The ARS animal health research program protects and ensures the safety of the nation’s agriculture and food supply through improved disease detection, prevention, and control. These research-based programs discover and develop diagnostics, vaccines, biotherapeutics, disease management systems, and farm biosecurity measures to control animal diseases. The following accomplishments highlight ARS advances in animal health research in FY 2019. Hyperlinked accomplishment titles point to active parent research projects.

African swine fever candidate vaccines transferred to industry. ASF viruses cause infections in domestic pigs that are often fatal and are characterized by fever and hemorrhages. ASF has been known as a disease of sub-Saharan Africa, but in 2007 a very virulent viral strain of ASF was introduced into the Republic of Georgia. Subsequently, the virus (Georgia 2007) started to spread to the Russian Federation, reached the European Union in 2014, and in 2018, the disease reached the world’s largest pig producer, China. Thus, the disease has invaded three continents over the last decade and ASF now has an unprecedented geographical scope and poses a major threat to the U.S. swine industry. There is no vaccine available for ASF and disease control is strictly dependent on animal quarantine, biosecurity measures, and slaughter. This presents a major gap in the availability of veterinary medical countermeasures to effectively prevent, control, and eradicate an ASF outbreak. In 2019 ARS scientists in Orient Point, New York successfully developed ASF candidate vaccines and transferred them to five pharmaceutical companies. Important milestones included the submission of patents to the U.S. Patent and Trademark Office, five U.S Government Patent and Biological Material Licenses, and one Cooperative Research and Development Agreement. These key milestones set the stage to begin the process of developing the first safe and effective commercial ASF vaccine.

ARS to conduct international African swine fever workshop. With the help of the ARS Office of International Research Engagement and Cooperation, ARS applied for and received USDA Foreign Agricultural Service funding to conduct an international African swine fever workshop with China. The workshop will identify knowledge gaps and tools to control and eradicate African swine fever. ARS scientists have entered into an agreement with collaborators at the U.S.-China Center for Animal Health at Kansas State University to implement this workshop.

Study reveals pigs can transmit foot-and-mouth disease (FMD) before showing signs of sickness. The FMD virus spreads much more aggressively in pigs than previous research suggested, according to ARS scientists at the Plum Island Animal Disease Center. A new study shows that pigs infected with FMD can infect other pigs just 24 hours after becoming infected, long before showing any clinical signs of FMD. Before this research occurred, experts believed FMD transmission in pigs did not occur before visible signs of illness developed, so previous disease-dynamics models to predict disease impacts and estimate outbreak resource requirements did not account for the impact of preclinical transmission. When ARS scientists and Animal and Plant Health Inspection Service collaborators used this new information in models that project disease transmission rates, estimates for the number of U.S. farms that would be affected by FMD outbreaks increased 40 percent. This increase translates into 166 additional farms and more than 664,000 additional pigs requiring euthanasia. Failure to account for new information such as this could make the difference between preparing for a limited, well-controlled FMD outbreak in the United States costing $3 million over 2 months and a catastrophic nationwide epidemic costing $20 billion over 1 year. Infectious disease modeling is a critical part of preparedness and protection of U.S. livestock. Research such as this provides critical information to help build better models to protect livestock industries from FMD.

Understanding and detecting Brucella abortus vaccine RB51 shed in milk. B. abortus is a highly contagious bacterial pathogen for livestock and humans and is classified as a select agent because of its potential use as a bioweapon. In the United States, a vaccine strain called RB51 is routinely used to vaccinate female calves to prevent infection and limit human exposures. Over the past 2 years, people in at least three States have been infected with the B. abortus RB51 vaccine strain after drinking unpasteurized milk. ARS scientists in Ames, Iowa, collaborated with colleagues at the Centers for Disease Control and Prevention and the Animal and Plant Health Inspection Service to better understand why some cattle vaccinated as calves shed RB51 in their milk as adults. Their results showed cattle that shed RB51 in milk have a different type of immune response than animals that do not shed RB51 in their milk. ARS further developed an assay that can detect cattle-shed RB51 in milk. Due to the widespread use of RB51 vaccination in cattle, this research is critical to the work of protecting public health and understanding why some cattle become persistently infected with the vaccine strain.

A new United States swine pathogen database (https://swinepathogendb.org). In recent years, several deadly viral diseases of pigs have emerged in the United States causing hundreds of millions of dollars in economic damage. To effectively respond to these diseases or detect new disease incursions or viral variants, it is critical to have a database of currently circulating viral genetic sequences and associated tools to analyze the sequences. ARS scientists in Ames, Iowa, created such a database for porcine reproductive and respiratory syndrome virus, Senecavirus A, and porcine epidemic diarrhea virus using nucleotide sequences and related metadata found in GenBank, part of the National Center for Biotechnology Information, and from clinical cases detected by key veterinary laboratories. Presently, the South Dakota Animal Disease Research and Diagnostic Laboratory, Iowa State Veterinary Diagnostic Laboratory, and Kansas State University Veterinary Diagnostic Laboratory have submitted more than 2,000 sequences. A suite of web-based tools allows stakeholders, researchers, and veterinarians to quickly search for genetic sequence information, identify similar viruses, and browse virus genomes to inform their research and control efforts. Databases such as these will greatly increase researchers’ understanding of endemic circulating viruses and speed response efforts by helping them to quickly identify new viral variants.

Creating the next generation of biodefense researchers. In 2019, ARS created workforce development training agreements with Auburn University, University of Connecticut, and University of Minnesota. All three universities are new National Bio- and Agro-Defense Facility (NBAF) training partners with ARS. These agreements will support new trainees in immunology/vaccinology, epidemiology, and disease pathogenesis. The goal of this program is to provide a cadre of qualified scientists who can compete for NBAF positions when they become available. Seven trainees are currently in place at Mississippi State University and Kansas State University, and ARS scientists are involved in all these research training projects. ARS held a research symposium for the workforce development trainees and their USDA and university mentors in Manhattan, Kansas, on August 27, 2019. This symposium provided trainees the opportunity to visit Manhattan, tour the NBAF, provide updates on their scientific projects, and meet USDA leaders.