Pseudorabies: What is Mad Itch or Aujeszky’s Disease in Pigs

What is Pseudorabies? Pseudorabies is a disease that literally drives swine mad with scratching. It’s also known as “Mad Itch”  and Aujeszky’s disease (named after the founder Aladar Aujesky). It’s is a strain of the DNA herpes virus that attacks your pig’s immune system.

Unfortunately, as a result, because of their weakened body’s inability to fight off bacteria, your pig will be vulnerable to other illnesses and infections. If not addressed right away, this could result in serious illnesses or even death.

Your pig will scratch, lick, and chew at itchy skin patches that have developed concentrated and intense itching. This results in lesions, which further irritate and itch the skin. Young pigs are most commonly affected by the “mad itch” disease, which is fatal to piglets younger than seven days old.

Aujeszky’s Disease Signs

Pseudorabies, also known as Aujeszky’s disease or the “Mad Itch,” is a DNA herpes virus that affects a pig’s respiratory, nervous, and reproductive systems. It causes high death rates, coughing, sneezing, circling, and poor coordination. It can cause paralysis, fevers, and difficulty breathing.  Young pigs are at high risk for catching this disease, and almost all piglets under seven days old that are infected die.

Pseudorabies hinders the body’s ability to process and destroy bacteria, resulting in death if not caught in time. Many studies (see references) Pseudorabies not to be transmittable to people, but at least one study has looked at the ability of the virus to infect humans. Pseudorabies disease always originates with pigs but is highly contagious to almost all other mammals and many birds.

What Is The Cause Of Pseudorabies?

Pseudorabies is “caught” from infected swine. Pigs don’t always show symptoms of mad itch. 

What is the mortality rate of Pseudorabies Disease? Depending on the age of your pigs, the mortality rate of pseudorabies varies. Piglets can have a mortality rate of up to 100%. The older the pigs are, the lower the mortality rate. It drops by half after one month of age, and by the time they are five months old, less than 5% of pigs will die. 

The Pseudorabies virus transmits through nose-to-nose contact or the ingestion of feces or contaminated manure. The virus is airborne. It can transmit as an aerosol for up to 1.24 miles (without strong wind).

This virus can also survive for almost 7 hours in drinking water, two days in feces, and three days in pelleted pig feed. This particular virus can also survive for four days in straw bedding.

It’s important to remember that the virus strain and the animals’ overall health can have an impact on the disease’s severity and the mortality rate that results.

How Do I Know If My Pig Has Mad Itch?

A tell-tale sign that your pig has contracted pseudorabies is their almost obsessive scratching at an “itchy spot.” Your pig may also have difficulty breathing due to coughing and sneezing fits. 

Unfortunately, some pigs also develop pneumonia and lose their appetite, which can lead to weight loss, listlessness, and difficulty breathing.

Look out for these symptoms if you suspect your pig has pseudorabies:

Symptoms of Pseudorabies or Mad Itch?

Depending on the age and species of the affected animal, Pseudorabies Disease, also known as Aujeszky’s disease (Mad Itch), can exhibit a variety of clinical signs.

Pig Pseudorabies: In pigs older than two months, respiratory infections are typically asymptomatic but can result in abortion. Piglets under seven days old are especially vulnerable; losses can reach 100%. Younger swine frequently exhibit clinical signs of central nervous system (CNS) disease, such as tremors and paddling. In contrast, respiratory disease is the main clinical issue in weaned pigs, particularly if it is complicated by secondary bacterial pathogens.

Pseudorabies disease is contagious to cattle, dogs, cats, sheep, and goats who come in contact with infected swine. Symptoms include fever, lethargy, respiratory issues, and neurological symptoms like convulsions, trembling, and paralysis.

Remember that Pseudorabies Disease is contagious. If your pigs get it, it can result in sizable financial losses for you. If you suspect pseudorabies, call your vet right away.

• Intense pruritus (itching skin)
• Circling
• Paralysis
• Fever
• Breathing difficulties
• Coughing fits
• Loss of appetite
• Listlessness
• Sneezing
• Abortions
• Stillbirth
• Mummified piglets
• Pneumonia

How is Pseudorabies Or Aujeszky’s Disease Transmitted? 

Pigs can carry the disease Aujesky’s without displaying any signs of infection. It’s highly contagious and capable of dispersing as an aerosol for a distance of 1.24 miles.

Another method by which the disease spreads within the herd is through nose-to-nose contact and eating contaminated feces. The virus can survive in water for up to seven hours and in contaminated pig feces for two days.

Suid herpesvirus 1, a swine-specific herpesvirus, is the root cause of pseudorabies. Despite its name, it is unrelated to the rabies virus. The virus is capable of infecting a wide range of animals, including swine, cattle, dogs, cats, sheep, and goats. It causes reproductive and respiratory issues as well as sporadic deaths in breeding and finishing hogs. Pigs older than two months old with respiratory infections typically show no symptoms, but piglets and mature pigs with respiratory infections may exhibit coughing, sneezing, fever, constipation, depression, seizures, ataxia, circling, and excessive salivation.

Aujeszky’s Disease in Dogs

Dogs usually get Aujeszky’s Disease when they come in contact with infected feral swine (or eat the meat of infected swine). This puts hunting dogs at a slightly greater risk. 

Fever, severe localized itching, respiratory distress, and symptoms of Aujeszky’s disease in dogs, such as circling, paralysis, and manic behavior, are some of the symptoms. In dire circumstances, sudden death is possible. Dogs can contract the virus by ingesting infected tissues or coming into contact with infected secretions or excretions.

Pseudorabies in Cattle 

When it was discovered, Aujeszky first noticed infected cattle and dogs. He later realized that both species had been in contact with pigs carrying Pseudorabies. In cattle, symptoms of pseudorabies include intense itching followed by neurological signs and death. 

Aggressive measures have eradicated it from commercial swine and cattle herds in the USA.  

What food animal is frequently affected by Aujeszky’s Disease? Aujeszky’s Disease (Pseudorabies) can infect pigs, cattle, goats and sheep. It can spread when one animal eats the raw carcass of an infected animal, usually hogs. Fortunately, it does not spread to humans. However, because some diseases can mutate and switch hosts- you should not eat an infected animal with Pseudorabies. 

Treatment for Pseudorabies or Aujeszky’s Disease

There is no cure for Pseudorabies. The only effective way to “cure” pigs is to vaccinate them. Additionally, improvements in biosecurity, vaccination, and culling of seropositive animals are all effective ways to control Aujeszky’s Disease in pigs. 

Pseudorabies is a contagious viral illness that primarily affects pigs and is brought on by Suid herpesvirus 1. (SHV-1). 

It is important to note that, aside from humans, horses, and birds, this virus only naturally infects pigs. However, it can also infect dogs, cats, cattle, sheep, goats, and wildlife including opossums, raccoons, rodents, and skunks.

Preventing Aujeszky’s Disease

Prevention trumps a cure at any time, so you must vaccinate your pig with a modified live vaccine. Ensure that your pig’s living area is clean, as the Pseudorabies virus can survive in damp and soiled straw/hay bedding.

If your pig is scratching continuously and hasn’t opened any sores, then you can apply topical hydrocortisone cream or Benadryl to the itchy area. This will drastically ease the “mad itch,” and you should see a noticeable difference in a couple of days.

If the scratching worsens and sores are opening on your pig’s skin, you’ll need to seek veterinary assistance.

Pseudorabies FAQs

Is Pseudorabies in the USA? Pseudorabies is not present in domesticated herds of pigs or cattle. It is found in the USA in very small percentage of wild swine or ferrel herds. While it has been in the USA for 150 years, because of the extremely low levels of Pseudorabies in the US, currently, all 50 states are considered to be free of it.

Is Pseudorabies The Same As Rabies? Despite the similar name, Pseudorabies is not related to rabies. It shares many of the same symptoms as rabies. The shared symptom of excessive drooling is the reason it’s name is so similar to that of rabies. 

Can Humans Get Pseudorabies or Aujeszky’s Disease? Fortunately, people cannot catch Pseordorabies. It can only transmit to swine, cattle, dogs, cats, sheep, and goats. It can affect most other mammals, such as opossums, raccoons, rodents, and skunks. It cannot transmit to horses, humans, or birds.  

References:

Iowa State University:

Pseudorabies – PRV | Iowa State University (iastate.edu)

Pennsylvania University Wildlife Futures Program

Pennsylvania University Wildlife Futures Program

World Organization for Animal Health World Organization for Animal Health

U.S. Department of Agriculture Pseudorabies (PRV)

National Library of Medicine Pseudorabies virus: a neglected zoonotic pathogen in humans?

U.S. Department of Agriculture Swine: Pseudorabies

Research Gate Factors associated with stillborn and mummified pigletsin high-prolific sows