Symptoms & Treatment of Pseudorabies: A Comprehensive G

Characteristics of the Disease

In the natural world, viruses can reside within rodents without causing symptoms, effectively acting as carriers. Dogs and pigs that consume these infected animals may then contract the disease. Affected pigs primarily excrete the virus through nasal secretions, eye discharges, milk, vaginal secretions, and urine. Consequently, sick pigs can also serve as a source of infection for dogs, and the virus can be transmitted through skin wounds.

Clinical Symptoms

The incubation period for this disease ranges from 1 to 8 days, with some cases extending up to three weeks. Initially, affected dogs may appear listless, followed by restlessness, loss of appetite, hunching, and frequent changes in sitting locations. Their body temperature may intermittently rise, and they may vomit. Dogs infected through the digestive tract may exhibit severe drooling and difficulty swallowing, starting with staring and licking, followed by scratching at skin injuries, leading to extensive ulcers with swelling and even deep lesions. Some dogs may not feel itchy but will whine due to pain in certain body parts; others may bite at objects around them, jump towards walls, and fall, showing no aggression towards humans but may fight with other dogs when itchy. The reflex excitement is initially increased, but later, the pupillary reflex, muscle sensation, and deep and superficial reflexes are diminished. Most cases show intermittent spasms in the flexor muscles of the head and neck, difficulty breathing, and often die within 24 to 36 hours.

Pathological Changes

Commonly, there are selfinflicted or擦伤 on the skin, with oozing fluid or blood. Postmortem examination reveals marked meningeal congestion and an excessive amount of cerebrospinal fluid. Histologically, the central nervous system shows diffuse nonsuppurative meningitis and neuritis, with distinct vascular sheaths and diffuse local gliocytic reactions, along with widespread necrosis of nerve cells and glial cells. In routine examinations, 15% to 20% of cases show no encephalitis changes.

Differential Diagnosis

(1) Distinction between Rabies and Pseudorabies

Both diseases present with symptoms such as restlessness, excitement, drooling, biting various objects, and selflicking. The difference lies in the fact that rabies patients exhibit disorientation, paralysis of the lower jaw, and the "hydrophobia" phenomenon, being aggressive towards humans and animals. Pseudorabies patients often die suddenly, with an intense itching sensation, and show no aggression towards humans or animals.

(2) Differentiation between Pseudorabies and Canine Meningitis

Both diseases present with symptoms such as fever, excitement or depression, fear, vomiting, sensitivity to touch, and aggression. The difference is that canine meningitis patients do not have infectiousness, may wander aimlessly, not avoiding obstacles, or perform circular movements. Postmortem examination reveals nonsuppurative inflammation in the brain tissue, with an increase in protein and cell content in the cerebrospinal fluid.

Advice

Dogs that frequently enter pig pens (where pseudorabies may occur) typically exhibit symptoms such as skin itching, selfmutilation by biting the skin, and biting objects around them, without attacking humans. They may have unequal pupil sizes and reduced reflexes later on. Postmortem examination may show meningeal congestion, an excessive amount of cerebrospinal fluid, and necrosis of nerve ganglia and glial cells. A preliminary diagnosis can be made based on these clinical symptoms and pathological changes, but laboratory tests are necessary for confirmation.

Preventive Measures

(1) Prevention

① Eliminate rodents from dog shelters and prevent dogs from entering pig pens, especially when pseudorabies is present in pigs. Prohibit feeding dogs with diseased pork.

② In the event of an outbreak, strictly disinfect the ground and utensils with a 1%2% sodium hydroxide solution. As of now, there is no suitable vaccine available. Lowpathogenic, genetically stable Kstrain tissue culture vaccines or chicken embryo cell aluminum hydroxide formalin vaccines can be tried.

③ There have been reports that pseudorabies can infect humans, causing an itchy sensation. Therefore, when handling sick dogs or carcasses, prevent wound infections.

(2) Treatment

Early administration of antipseudorabies hyperimmune serum or the gamma immunoglobulin prepared from it can be effective for treating affected dogs (dosage should be as per the instructions). If neurological symptoms have already appeared, the effectiveness is poor. Various antibiotics and chemical drugs are ineffective.

Caution

Pseudorabies is a zoonotic disease affecting multiple animals, with rodents being the primary vectors. Therefore, pet farms should prioritize rodent control to prevent the spread of the virus.