Equine Viral Arteritis

AGENCY:

Animal and Plant Health Inspection Service, USDA.

ACTION:

Advance notice of proposed rulemaking and request for comments.

SUMMARY:

We are soliciting public comment to help us develop options for an equine viral arteritis regulatory program for horses within the United States. Equine viral arteritis is primarily a respiratory disease of horses. Equine viral arteritis is not widespread in the United States; however, the equine industry within the United States regards the disease as a potentially significant and increasing economic threat. After evaluating public comment on the issues presented in this document, we will determine whether to propose changes to our regulations.

DATES:

We invite you to comment on this docket. We will consider all comments that we receive by November 20, 2000.

ADDRESSES:

Please send your comment and three copies to: Docket No. 99-074-1, Regulatory Analysis and Development, PPD, APHIS, Suite 3C03, 4700 River Road, Unit 118, Riverdale, MD 20737-1238.

Please state that your comment refers to Docket No. 99-074-1.

You may read any comments that we receive on this docket in our reading room. The reading room is located in room 1141 of the USDA South Building, 14th Street and Independence Avenue, SW., Washington, DC. Normal reading room hours are 8 a.m. to 4:30 p.m., Monday through Friday, except holidays. To be sure someone is there to help you, please call (202) 690-2817 before coming.

APHIS documents published in the Federal Register, and related information, including the names of organizations and individuals who have commented on APHIS dockets, are available on the Internet at http://www.aphis.usda.gov/ppd/rad/webrepor.html.

FOR FURTHER INFORMATION CONTACT:

Dr. Timothy Cordes, Senior Staff Veterinarian, National Animal Health Programs Staff, VS, APHIS, 4700 River Road Unit 43, Riverdale, MD 20737-1231; (301) 734-3279.

SUPPLEMENTARY INFORMATION:

Background

The regulations in 9 CFR part 75 (referred to below as the regulations) govern the interstate movement of horses, asses, ponies, mules, and zebras that test positive for communicable diseases. The purpose of the regulations is to prevent the interstate spread of communicable diseases in equines. Equine viral arteritis (EVA) is not currently addressed by the regulations.

EVA is an acute, contagious, viral disease characterized by fever, edema, conjunctivitis, nasal discharge, and abortion. Aerosol transmission is the principal means of the spread of infection among horses that are closely congregated in places such as racetracks, shows, and sales. However, the disease can also be spread venereally by infected stallions or infected semen. In fact, infected stallions play a significant role in maintaining EVA infection in horse populations.

When a mare, gelding, or sexually immature colt becomes infected with EVA, the disease will run its course and the animal will eliminate the virus. However, when a stallion becomes infected with EVA, the EVA virus localizes in the stallion's reproductive system, and the stallion becomes a reservoir of the disease. As a consequence, the EVA virus can be shed continuously in the stallion's semen. If a stallion is serologically positive, it has a 50 percent chance of shedding the virus in its semen. Virus isolation can be performed on the stallion's semen to determine whether the stallion is shedding the EVA virus. If the stallion is shedding the EVA virus in its semen, the stallion is considered a shedder. Stallions that are shedders can infect mares during breeding, and infected mares can spread the disease to their foals in utero or to other horses through aerosol transmission.

EVA can pose a number of problems for horse owners, horse breeders, and the equine performance industry. Horses that have EVA antibodies, which can be present due to vaccination against the disease or infection with the EVA virus, can be barred from entering foreign countries for racing or competition purposes. In addition, semen collected from stallions that are shedders is barred from importation into many countries. However, economically, the most damaging aspect of EVA is that the disease can cause abortion in pregnant mares. Abortion rates due to EVA can be as high as 70 percent.

At this time, the Animal and Plant Health Inspection Service (APHIS) does not have a program to control EVA because the disease is not perceived to be widespread in the United States, and confirmed outbreaks are sporadic. However, the equine industry within the United States has requested that APHIS initiate surveillance, control, and possibly eradication of EVA and has indicated a willingness to assist in the implementation of such programs. This document requests public comment on five possible programs to address EVA. Each program is discussed below, and each succeeding program is more restrictive.

Minimal Voluntary Program

The U.S. equine industry would develop, manage, and monitor this program. This program would include an educational program for equine producers and equine practitioners regarding the etiology, treatment, and prevention of EVA. In addition, this program would include a method, to be determined by the equine industry, to identify infected semen and stallions that are shedders. APHIS would not have regulatory involvement with this program.

Voluntary Control Program

The U.S. equine industry would develop, manage, and monitor this program with cooperation from APHIS and individual States. This program would include an educational program for equine producers and equine practitioners regarding the etiology, treatment, and prevention of EVA. In addition, APHIS would quarantine imported stallions at the time of arrival and test them to determine whether they are serologically positive for EVA. APHIS would also test imported equine semen for EVA at the time of arrival. APHIS would note the test results on the import permit accompanying the stallion or semen, release the stallion or semen, and notify animal health regulatory officials in the State of destination of any that were positive. APHIS would recommend that each State determine whether to conduct further testing of positive stallions upon entry into the State.

APHIS would also recommend that each State develop an EVA program that includes testing domestic stallions and semen for EVA and controlling the intrastate movement of EVA-positive stallions, stallions that are shedders, and infected semen. In addition, APHIS would recommend that States make all test results for domestic and imported stallions and semen a matter of public record.

Voluntary and Uniform Control Program

The U.S. equine industry would develop, manage, and monitor this program with cooperation from APHIS and individual States. This program would include an educational program for equine producers and equine practitioners regarding the etiology, treatment, and prevention of EVA. In addition, APHIS would develop a program standards document entitled, “Uniform Methods and Rules—Equine Viral Arteritis” (UM&R). APHIS would draft this document with cooperation from the States, the equine industry, and other interested entities. The UM&R would be based on standards set by the Office International des Epizooties and guidelines of the American Horse Council. The UM&R would contain uniform standards that States could use for detecting, controlling, and preventing EVA, as well as recommended standards for the intrastate and interstate movement of stallions that are serologically positive for EVA, stallions that are shedders, and infected semen. The UM&R would be available for use as a guidance document only.

As in the Voluntary Control Program, APHIS would quarantine imported stallions at the time of arrival and test them to determine whether they are serologically positive for EVA. APHIS would also test imported equine semen for EVA at the time of arrival. APHIS would note the test results on the import permit accompanying the stallion or semen, release the stallion or semen, and notify animal health regulatory officials in the State of destination of any that were positive. APHIS would recommend that positive stallions be moved to an approved location in the State of destination for virus isolation testing by the State.

APHIS would also recommend that each State develop an EVA program that includes testing domestic stallions and semen for EVA. As part of this program, APHIS would recommend that each State determine the serology of a stallion upon entry into the State and record its test result on the stallion's health certificate. APHIS would recommend that the State conduct a virus isolation test on positive stallions. APHIS would also recommend that each State test equine semen for EVA upon entry into the State and record its test result on the semen's health certificate. APHIS would further recommend that infected semen and stallions that are positive or shedding the EVA virus be handled in accordance with the UM&R. In addition, APHIS would recommend that States make all test results for domestic and imported stallions and semen a matter of public record.

Certification Program

APHIS would develop this program with cooperation from individual States and the U.S. equine industry. This program would include an educational program for equine producers and equine practitioners regarding the etiology, treatment, and prevention of EVA. It would include use of the UM&R previously described and a new component a certification program that States could participate in.

As in the previous two programs described, APHIS would quarantine imported stallions at the time of arrival and test them to determine whether they are serologically positive for EVA. APHIS would also test imported equine semen for EVA at the time of arrival. APHIS would note the test results on the import permit accompanying the stallion or semen and release the stallion or semen. However, APHIS would release imported positive stallions and infected semen only to States participating in the certification program. In addition, APHIS would restrict the interstate movement of known domestic infected semen and stallions that are positive or shedders to those States participating in the certification program.

To be a participating State, a State would have to: (1) Conduct a virus isolation test on positive stallions upon movement into the State after release from APHIS import quarantine stations; (2) determine the serology of any domestic stallion upon its entry into the State, record the test result on the stallion's health certificate, and conduct a virus isolation test on stallions that test positive; (3) test domestic equine semen for EVA upon entry into the State and note the semen's status on its health certificate; (4) regulate the intrastate movement of infected semen and stallions that are positive or shedding the EVA virus in accordance with the UM&R. Also, APHIS would recommend that States make all test results for domestic and imported stallions and semen a matter of public record.

For a State that does not participate in the certification program, APHIS would recommend that the State develop an EVA program that includes testing domestic stallions and semen for EVA. As part of this program, APHIS would recommend that the State determine the serology of a stallion upon entry into the State, record the test result on the stallion's health certificate, and perform a virus isolation test on stallions that test positive. APHIS would also recommend that the State test equine semen for EVA upon entry into the State and record the test result on the semen's health certificate. In addition, APHIS would recommend that the State regulate the intrastate movement of infected semen and stallions that are positive or shedding the EVA virus in accordance with the UM&R. Also, APHIS would recommend that States make all test results for domestic and imported stallions and semen a matter of public record.

Eradication Program

APHIS would develop this program with cooperation from individual States and the U.S. equine industry. This program would include an educational program for equine producers and equine practitioners regarding the etiology, treatment, and prevention of EVA. It would include the use of the UM&R previously described.

Again, APHIS would quarantine all imported stallions at the time of arrival and test them to determine whether they are serologically positive for EVA. APHIS would move any imported stallion that tested positive for EVA to an APHIS-approved location for virus isolation testing to determine whether it was a shedder. APHIS would also test imported equine semen for EVA at the time of arrival. APHIS would record the test results on the import permit accompanying the stallion or semen. If APHIS determined that a stallion was not a shedder or that the imported semen was negative, we would release the stallion or semen. Positive stallions would be allowed to proceed to their destination; however, we would prohibit shedders and infected semen from entering the United States.

Under this program, APHIS would also require stallions and semen to be tested for EVA prior to interstate movement. The test results would have to be recorded on the health certificate accompanying the stallion or semen interstate. Also, APHIS would require a permit for the interstate movement of stallions that are shedders and infected semen. APHIS would recommend that each State conduct a virus isolation test on a stallion's semen the first time it is used for breeding purposes in that State. APHIS would also recommend that infected semen and stallions that are positive or shedding the EVA virus be moved intrastate in accordance with the UM&R. In addition, APHIS would initiate an EVA-vaccination program for domestic mares.

We welcome comments on the options described above and encourage the submission of new options or any suggestions.

Authority: 21 U.S.C, 111-113, 115, 117, 120, 121, 123-126, and 134-134h; 7 CFR 2.22, 2.80, and 371.4.