Swine (Porcine)

Senecavirus A, (SVA), belongs to the same family as foot and mouth disease (FMD) "Picornaviridae." It has been identified in U.S. swine since the 1980s and is occasionally implicated in sporadic outbreaks of idiopathic vesicular disease. SVA has been frequently associated with clinical signs and gross lesions that are indistinguishable from vesicular foreign animal diseases (FADs), including foot and mouth disease (FMD), vesicular stomatitis (VS) and swine vesicular disease (SVD), making rapid response and differential diagnosis imperative.

Clinical cases of SVA in swine have significantly increased, drawing industry and regulatory attention to the virus. All cases of vesicular disease must be reported to MDA/USDA to ensure rapid detection of catastrophic diseases such as FMD. As vesicular lesions can be caused by several diseases, including FMD, MDA and USDA Veterinary Services (VS) foreign animal disease diagnosticians respond to cases immediately by conducting a FAD investigation and sending samples to the NAHLN Laboratory to test for FADs the same day. The exposed animals will be quarantined pending test results.

Senecavurs A Fact Sheet

Swine brucellosis is an infectious disease caused by the Brucella bacteria. Like the National Pseudorabies Eradication Program, USDA has established guidelines for a Swine Brucellosis Control/Eradication Program. This program has three (3) stages that each state must complete before achieving brucellosis-free status. Missouri was declared free of swine brucellosis in 1992.

Uniform methods and rules for establishing and maintaining validated brucellosis-free swine herds as recommended by the Missouri Department of Agriculture and the United States Department of Agriculture are as follows:

Herd Validation

Initial Validation

1. Swine herds may be validated or revalidated as swine brucellosis (SB) free by conducting a Complete Herd Test (CHT) that has negative results, or
2. By subjecting all breeding swine over six months of age to an incremental CHT through testing 25 percent of the swine over six months of age every 80–105 days and finding all swine have tested negative, or by testing 10 percent of the swine over six months of age every 25–35 days and finding all swine have tested negative. A herd may be validated as SB free when all its breeding swine have been tested and found negative, or
3. Swine herds may be validated or revalidated as SB free if all samples are tested SB negative when establishing a Qualified Pseudorabies-Negative (QN) or Qualified-Negative Gene-Altered Vaccinated (QNV) breeding herd.

Swine may not be tested twice in one year to comply with the 25 percent requirement, or twice in 10 months to comply with the 10 percent requirement.

Maintaining Herd Validation

1. Validation is good for a maximum of 12 months without further testing. After 12 months, the herd must be revalidated. There is no grace period.
2. Validation may be continuously maintained by testing 25 percent of the swine over six months of age every 80–105 days and finding all swine have tested negative, or by testing 10 percent of the swine over six months of age every 25–35 days and finding all swine have tested negative, or
3. Validation may be maintained by testing SB negative all samples submitted to maintain QN or QNV herds.

Swine may not be tested twice in one year to comply with the 25 percent requirement, or twice in 10 months to comply with the 10 percent requirement.

General Considerations

1. Clinical signs—There must be no evidence of infection at the time of initial validation or revalidation.
2. Suspects—Swine that are positive to an official SB presumptive test and negative to a confirmatory test should be evaluated by a designated brucellosis epidemiologist.
3. Reactors—When an animal that reacts positively to the card test is found in a validated herd, the infection status of that animal, and ultimately the herd, must be determined by a designated brucellosis epidemiologist. Once a herd is determined to be infected, the herd will be held under quarantine until it meets the quarantine release requirements of Part IV. Card-positive reactors that are considered not infected should be retested every 30–60 days or slaughtered and tissue-cultured in accordance with Part III, F. Bacteriology.

Movement of Swine into Validated Herds

1. Movement between validated brucellosis-free herds does not require an official brucellosis test.
2. Movement of breeding swine from a non-validated brucellosis-free herd requires one negative test within 30 days prior to movement. These animals must be isolated and retested 30-60 days after arrival.
3. Breeding swine are not permitted to enter validated brucellosis-free herds from feedlots or slaughter confinements.
4. Use of swine semen in swine brucellosis-free herds must come from boars in validated brucellosis-free herds.

Pseudorabies (PRV), also known as Aujeszky’s disease, is a swine disease that can also affect cattle, horses, dogs, cats, sheep and goats. The disease is caused by an extremely contagious herpes virus that causes reproductive problems including abortion and stillbirths, and even occasional deaths in breeding and finishing hogs.

In 1989, the United States Department of Agriculture (USDA) developed guidelines for the National Pseudorabies Eradication Program to eradicate pseudorabies from the United States. The program consists of five stages, Stage I, II, III, IV and V, with V being pseudorabies-free. Every state must complete the requirements of each stage and apply annually for advancement in the program. Missouri has been recognized as Stage V, pseudorabies-free since May 1999, thanks to the cooperation and support of Missouri’s swine producers and industry leaders.

Program Standards for establishing and maintaining qualified pseudorabies-free swine herds as recommended by the Missouri Department of Agriculture and the United States Department of Agriculture are as follows:

Establishing a Qualified Pseudorabies-Negative (QN) Breeding Herd

1. For breeding herds, QN status is attained by (1) subjecting to an official pseudorabies serologic test for all swine over six months of age, plus a number of progeny equal to 20 percent of the breeding swine population of the herd, and (2) finding that all swine are negative to the test. Progeny shall be randomly selected from swine between four and six months of age. The herd must not have been a known infected herd within the 30 days prior to the qualifying test. A minimum of 90 percent of the swine in the herd must have been on the premises and a part of the herd for at least 60 days prior to the qualifying official pseudorabies serologic test or have entered by direct shipment from another QN herd.
2. When all swine are shipped directly from existing QN herds, a new QN breeding herd may be established if, within 30 days of arrival, all swine in the initial shipment (up to 50 animals) are tested and found negative to an official pseudorabies serologic test.
3. Any breeding herd in a Stage IV or V State/Area is recognized as a QN herd.

Maintaining Qualified Pseudorabies-Negative (QN) Herd Status

QN Breeding Herd Status may be maintained by monthly or quarterly pseudorabies testing as follows:

1. Monthly testing: Every 30 days, conduct an official pseudorabies serologic test of seven percent of all breeding swine six months of age or older, and test a number of offspring four to six months of age located on the same premises as the breeding herd equal to two percent of the breeding animals in the herd, or
2. Quarterly testing: Every 80 to 105 days, conduct an official pseudorabies serologic test of 20 percent of all breeding swine six months of age or older, and test a number of offspring four to six months of age located on the same premises as the breeding herd equal to 6 percent of the breeding animals in the herd.

Swine may not be tested twice in one (1) year to comply with the 20 percent requirement, or twice in 10 months to comply with the seven percent requirement. All swine tested shall be randomly selected and, in the case of the adult swine, representative of all age groups on the premises.

Additions to Qualified Pseudorabies-Negative (QN) Herds

1. All swine intended to be added to a QN herd shall be isolated until they are negative to an official pseudorabies serologic test conducted 30 days or more following their placement in isolation, except:
   1. Swine from a herd of unknown status must be negative to an official pseudorabies serologic test not more than 30 days prior to movement, with a second test in isolation at least 30 days after movement.
   2. Swine intended to augment a QN herd that are coming directly from another QN herd may be added without isolation or testing.

Swine intended to be added to a QN herd from another QN herd, but with interim contact with swine other than those from a QN herd, shall be isolated until they have been found negative to an official pseudorabies serologic test, conducted 30 days or more after the swine have been placed in isolation.

The U.S. Swine Health Improvement Plan (US-SHIP) is a national program that establishes consistent health standards that serve as a platform for control of foreign animal diseases (FAD) of high consequence like African Swine Fever (ASF) and Classical Swine Fever (CSF). It also has benefits for the control of endemic diseases. The US SHIP is a collaborative effort involving industry, state, and federal partners providing standards for certifying the health status of swine across participating farm sites, supply chains, states and regions.

The US-SHIP ASF-CSF Monitored certification aims to mitigate risks of disease introduction and provide a practical means for demonstrating evidence of freedom of disease (outside of foreign animal disease control areas) in support of ongoing interstate commerce and a pathway towards the resumption of international trade over the course of a trade-impacting disease response and recovery period. The U.S. SHIP is designed to be applicable across the full spectrum of U.S. pork industry participants from the small show pig farmer to the large commercial producers and slaughter facilities.

Benefits of US-SHIP Participation

• Strengthen state and producer ASF/CSF preparedness through prevention, response and recovery planning.
• Established uniformed biosecurity, tracing, and testing procedures and requirements for participants.
• Provides a collaborative program between producers, state and federal agencies to create appropriate standards for swine health certifications.
• Assists in returning to normal business operations faster in the event of a disease outbreak.

Requirements of participation in US-SHIP

• Complete the enrollment form at the US-SHIP website and submit to the designated Official State Agency (OSA) for Missouri.
• Take the online biosecurity survey.
• Be prepared to provide 30 days of movement information in an electronic format to MDA when requested.
• Have a Secure Pork Supply Plan in place.
• Obtain a premises ID from MDA at 573-751-3377.

Helpful Resources

US-SHIP website
US-SHIP Brochure