Primary infection results in varicella (chickenpox)
Incubation period of 14-21 days
Presents fever, lymphadadenopathy. a widespread vesicular rash.
The features are so characteristic that a diagnosis can usually be made on clinical grounds alone.
Complications are rare but occurs more frequently and with greater severity in adults and immunocompromised patients.
Most common complication is secondary bacterial infection of the vesicles.
Severe complications which may be life threatening include viral pneumonia, encephalititis, and haemorrhagic chickenpox.