Causative agent
- AD virus or PR virus, family herpes viridae


Differential diagnosis
- Rabies
- Porcine parvovirus infection
- Streptococcal meningitis
- Hemophilus infection
- Classical swine fever
- Japanese B encephalitis


1. Epidemiology
- Swine are the only reservoir and serve as a source
  of infection
- Several species of domestic and wild animals are
  susceptible


2. Clinical examination
- In piglets, disorders of the central nervous system
- In weaners and fatteners, respiratory disease is
  the main feature but nervous signs may also be
  observed
- In sow and boars, reproductive disorders


3. Necropsy
- Marked congestion of the meninges, accompanied
  by excess of cerebrospinal fluid
- Congestion of nasal mucosa and pharynx
- Necrotic tonsilitis, pharyngitis, tracheitis and
  esophagitis
- Necrotic foci in liver, spleen, lymph nodes and
  kidney
- Petechial hemorrhages in the renal papillae and
  cortex

4. Histophathological observation
- Diffuse, non-suppurative
  meningoencephalomyeltis and ganglioneuritis
- Marked perivascular cuffing, diffuse and focal
  gliosis associated with extensive neuronal and
  glial necrosis
- Intranuclear inclusion bodies in tonsilar crypt,
  alveolar lining epithelium, nerve cells and glial cells
  in brain


5. Serological test
Specimens : paired sera
Method      : SN test


6. Antigen dectection
Specimens : brain, tonsil, lung, lymph nodes
Method      : FA test on cryostat section


7. Virus isolation
Specimens : 10% suspension of mixed organs of
brain, tonsil, lung, and lymph nodes
Method      : PK-15 inoculation and CPE observation


8. Virus identification
- FA test
- Immunohistochemistry staining


Control
- Stamping out gE⁺ positive pigs
- Culling
- Vaccination with gE^- - deleted vaccine