Mad Itch (Pseudorabies) in Dogs

The pseudorabies virus is also called Aujesky’s disease. It is caused by an alphaherpesvirus and affects organs of the body, along with the central nervous system. Pigs are the natural host but dogs, cats, farm animals like sheep, and wildlife such as skunks can contract the virus. Pigs are the only animals that are able to survive the infection, thus the explanation as to why they are the known host. However, young pigs under two weeks of age face a 100% mortality rate, and sadly a dog who contracts the virus faces the same fate. The commercial swine industry in North America is thought to be free of the pseudorabies problem, but it is known to be present in feral populations.

Pseudorabies, also called mad itch, is a dangerous herpes virus passed from nose to nose and fecal-oral contact, primarily in swine. Though rare, the condition can affect canines and is seen most commonly in farm dogs and those who travel in packs.

Dogs can be hosts for Aujesky’s disease, but will survive, at most, two to three days after infection. A canine who has been infected with the pseudorabies virus will show the following signs.

• Fever
• Respiratory distress
• Seizures
• Intense itching (pruritis), hence the name ‘Mad Itch’
• Central nervous system signs like erratic behavior, circling and eventual paralysis
• Physical sensitivity of the skin (hyperesthesia)
• Sudden death

The evident signs in dogs may mimic the rabies virus.

Types

The primary site of the replication of the virus is the tonsillar, pharyngeal, and nasal tissues. The spread can then invade tissues of the lymph nodes, brain, and spleen to name just a few. As the virus invades the body, it is replicating the entire time.

Transmission of this virus from swine to canines is rare in North America due to the intense efforts to eradicate the disease. Mainly, pseudorabies is transmitted from nose to nose contact between pigs, essentially because the virus is very evident in nasal secretions.

• Contaminated drinking water and feed buckets will contribute to the spread
• Viral infection in swine is seen after two to five days post infection
• The virus can be identified in milk, urine, nasal secretions, and tonsillar tissue of pigs
• People can carry the virus on their footwear, skin, or clothing after contact with pigs
• In the right conditions, the virus can survive for a few days in the grass, soil, shelled corn, and feces
• It is an aerosolized virus meaning it can be passed through droplets in the air that can persist up to seven hours
• Inhalation of the virus is possible

If your pet is exhibiting signs for pseudorabies, immediate veterinary care is essential. Though there is no cure, you do not want to see your pet suffer unnecessarily.  Be as proactive as you can in relaying important information to the veterinary team, such as past medical history, illnesses of late, and for certain, let the veterinarian know if your dog has been in contact with any pigs, commercial or feral, or whether he has visited a farm recently.

The veterinarian will consider other illnesses similar to pseudorabies. These could be a reaction to a drug, toxicity to a substance, canine distemper encephalitis, or rabies.  A blood test to look for antibodies against the virus could be done, as well as tests to  identify the virus in the tissues of your pet, such as nasal or tonsillar. However, studies show that dogs will succumb to the virus before antibodies are evident. Therefore, these diagnostic tools may be able to give a positive diagnosis, but this is not for certain.

At present, there is no treatment for dogs or other animals who contract Aujesky’s disease. Swine who contract the virus survive to become latent carriers, though piglets under the age of two weeks will die of encephalitis.

Although the pseudorabies virus is thought to be non existent in the commercial pig industry, the fact that feral pigs in North America can still contract the virus leaves the window open for re-introduction of the virus to farmed pigs if a feral swine comes in contact. It is thought that this virus can be transmitted through ingestion of undercooked or raw pork, therefore it is imperative to never feed your pet raw pork and to avoid the accidental ingestion of feral meat.