Ask Martok: Pseudorabies and Swine Brucellosis

Martok explains the dangers of these two diseases in pig herds.

by Dani Yokhna
Pig foraging
Courtesy iStockphoto/Thinkstock
Prevent pig diseases, like pseudorabies and swine brucellosis, from entering your herd by buying only animals that have been tested.

Q: Should you test pigs for pseudorabies and swine brucellosis before they come to your farm, or should you just examine them for any type of sickness?

A: Always buy tested pigs. Pseudorabies and swine brucellosis are serious, federally reportable diseases, so it’s important to not to bring them into your herd.

According to The Merck Veterinary Manual, pseudorabies virus—also called PVR, Aujeszky’s disease or mad itch—is an acute disease caused by a DNA herpesvirus. It’s not related to the virus that causes rabies. Pseudorabies occurs worldwide. Pigs are its natural host, but the virus also infects cattle, sheep, goats, and especially dogs and cats; it also affects many types of wildlife. Humans aren’t susceptible to it.

Ask MartokPseudorabies is transmitted by nose-to nose contact but also fecal-oral contact, so if one animal somehow ingests material contaminated by manure from another infected animal, it’s likely to get sick. Piglets younger than 2 weeks old are likely to die. Their symptoms include vomiting, weakness, coughing, sneezing and incoordination, but piglets often die before symptoms are noted. Symptoms in older pigs include coughing, nasal discharge, fever, abortions and reproductive complications.

Several vaccines exist for pseudorabies. They don’t always prevent the disease, but outbreaks tend to be milder in vaccinated herds. Farm-wide vaccination using a modified live virus is usually recommended, according to The Merck Veterinary Manual. Before starting a vaccination plan, it’s important to first consult your veterinarian.

The USDA mounted a successful, nationwide pseudorabies eradication program in 1989, so the disease has been eliminated from most domestic swine herds. It’s been reported, however, in feral swine from at least 11 states.

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Swine Brucellosis
Swine brucellosis is caused by a bacterium called Brucella suis, one of at least six similar Brucella that cause disease in humans and wild and domestic animals, such as cattle, worldwide. Although the disease is rare in domesticated herds, it’s important to buy from swine brucellosis-tested herds because there is no vaccine for the disease. Infected adult pigs sometimes appear to be perfectly healthy, though infected sows often abort or give birth to weak piglets. Once pigs are infected, they are carriers for life.

It was especially important to eliminate brucellosis from livestock species because it’s often fatal in humans (where it’s known as undulant fever). The Federal Brucellosis Eradication Program began in 1934, and swine brucellosis has since been nearly eradicated from America’s domestic livestock population. It’s still, however, found in sounders of feral hogs, especially in the southern portion of their range.

If you live where feral pigs are present (and according to the USDA brochure “Feral/Wild Pigs: Potential Problems for Farmers and Hunters,” that’s 39 of our 50 states), biosecurity is very important. Don’t allow feral hogs to mingle with your farmyard pigs, and don’t slaughter feral swine on your farm. Should you decide to adopt a wild hog like our first pig, Wilma, quarantine it and have it tested and cleared of disease before it meets or mingles with any other pigs.

About the Author: Ozark Jewels General Martok, who describes himself as “a really studly Nubian buck,” lives with his family and friends on a small farm in the Arkansas Ozarks. Read his blog, “Mondays with Martok,” for a peek at their daily animal activities.

Have an animal-related question? Send it to Martok at, and include “Ask Martok” in the subject.

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