Swine farms threatened with pseudorabies

This article submitted by Linda Stelling on 2/23/99.

First, in 1998, it was low hog prices, now in 1999 pseudorabies is threatening swine herds on Minnesota farms. The threat of quarantine has impacted about 234 farms in Minnesota including a few farms in Stearns and Kandiyohi counties.

Pseudorabies is a disease of swine that can also affect cattle, horses, dogs, cats, sheep, and goats. The disease is caused by a pseudorabies virus, which is extremely contagious herpes virus that causes reproductive problems, including abortion, stillbirths, and even occasional death losses in breeding and finishing hogs.

Pseudorabies isnít something new, it has existed in the United States for at least 150 years.

Dr. Leon Boehland, district veterinaian with the United States Department of Agriculture stationed in Willmar, said the herpes virus can kill a pet within 24 to 48 hours after nose-to-nose contact.

The virus can be transferred through water tanks, ventilation systems blowing from barns where pigs have tested positive, and nose-to-nose contact. A warm, moist breeze can also carry the virus to a neighboring farm.

Dr. Tom Hagerty, Minnesota Board of Animal Health, said the virus can survive in the air for only a short distance, about a mile.

When a farm is found to be infected with the pseudorabies virus, neighboring farms within a mile and one-half are tested for the virus.

Dr. Boehland confirmed there were four farms quarantined in Stearns County and three in Kandiyohi County.

Through the USDA eradication program, a Paynesville area farm was emptied of all pigs last week as well as another farm in Kandiyohi County. With the cleanup at these two farms, Dr. Hagerty said there are no other infected herds in Stearns or Kandiyohi counties.

ďWe are having a big problem in southern Minnesota because of their nearness to Iowa,Ē Dr. Boehland said.

As of Feb. 1, Iowa has more than 800 herds for a total of more than 600,000 swine quarantined. ďTheir laws are more lax than Minnesota when it comes to vaccinating swine,Ē he added.

ďThe infected numbers are probably greater than what has been reported,Ē he added. He explained that if a farmer owns more than one operation, every farm premises are quarantined, not just the home farm.

The eradication program for pseudorabies was established in 1989. The programís primary activities include surveillance, herd monitoring, and herd cleanup (shipping hogs to rendering plants). The hogs are not being slaughtered and processed for human consumption.

Due to the large number of swine herds affected by pseudorabies, the USDA is accelerating the eradication program by removing the herds to prevent further spread of the virus. The program will also help hog farmers financially during a particularly difficult time.

The current eradication program has reduced the number of pseudorabies-infected herds from 8,000 in 1992 to 1,110 today.

Farmers with known pseudorabies infected herds are being compensated based on present fair market value. Producers can be compensated for a herd even though only one hog is found infected with the virus, Dr. Boehland said.

Pork producers have the option of selling their herds or waiting out the quarantine period. The quarantine can last anywhere from 12 to 18 months or extend up to three years in some cases. ďAll pigs need to be tested negative before the quarantine is lifted,Ē Dr. Hagerty said.

Pork producers can repopulate their herds 30 days after approved cleaning and disinfection.

The United States is one of the worlds largest producers of pork and is the second largest exporter of pork.

The presence of pseudorabies in U.S. swine has a tremendous economic impact on the industryís yearly earnings. The cost to pork producers alone is over $40 million annually. Of this amount, more than half represents the cost of vaccination.

As of January 1999, there are 28 states and two territories free of pseudorabies and seven states are in the qualifying stage for free status.

ďOur goal is for Minnesota to be free of pseudorabies by the end of 2000,Ē Dr. Hagerty said.

•   •   •

Number of swine and herds under quarantine as of Jan. 1
States - Herds - Swine

Iowa - 600 - 510,000
North Carolina - 99 - 336,374
Indiana - 200 - 604,890
Minnesota - 150 - 212,000
Nebraska - 17 - 160,000
Michigan - 3 - 18,900
all other - 41 - 19,630
*Source, USDA Animal Health Dept.

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