Varicella-Zoster virus is not associated with -
Ans. is 'c' i.e., Centrifugal rash* Varicella zoster virus (VZU) is Herpes simplex virus type III (HSV-III) causative agent of chicken pox and herpes-zoster (shingle).* Varicella (Chicken pox) and Herpes zoster are different manifestations of the same virus infection. The virus is therefore called varicella zoster virus (VZA).* Primary infection with VZV causes chicken pox.* Reactivation of latent VZV, when immunity has fallen to ineffective levels causes-Herpes zoster* The virus remains dormant in sensory ganglion of trigeminal nerve and reaches the eye along one or morebranches of the opthalmic division of the 5th nerve.Chicken pox* The causative agent of chicken pox is Varicella - Zoster virus (Herpes simplex type III).* It is an acute respiratory infection with incubation period 10-21 days.* Infection is acquired through respiratory tract via air droplets or rarely from conjunctiva.* Infectious period (communicable period) for chicken pox is 2 days prior to 5 days after onset of rash, with a very high secondary attack rate of 90%.* Chicken-pox usually affects children of age group 5-9 years.* Clinical features of chicken pox has two stages1) Pre-eruptive stage# Characterized by fever, back pain, malaise and shivering.2) Eruptive stage# It is characterized by a characteristic rash with following features (which must be differentiated from rash of small pox)i) Superficial and unilocular (rash of small pox is deep seated and multilocular).ii) Symmetrical, mostly on flexor surface (rash of small-pox usually affect extensor surface).iii) Centripetal distribution (rash of smallpox has centrifugal distribution).iv) Affects axilla but spares palms and soles (rash of small-pox affects palms and soles but spares axilla).v) Pleomorphic, with appearance of all stages of rash simultaneously (rash is mon-omorphic in nature in small-pox).vi) Dew-drop on rose petal apperance (rash of small-pox has umblicated apperarance).vii) Area of inflammation around the rash (in small-pox there is no inflammation around the rash).viii) Evolution of rash is rapid, scabs begin to form 4-7 days after rash (evolution is slow, scabs begin 10-14 days after rash).* Though the disease affects children commonly, it is more severe in adults than in children.* Most common complication of varicella is secondary bacterial infection of skin, usually caused by streptococci or staphylococci. The most common extracutoneous site of involvement in children is CNS. Varicella pneumonia is the most serious complication following chicken - pox in adults. Important complications of chicken pox are:-i) Pulmonary: Pneumoniaii) CNS: Cerebellar ataxia, encephalitis, meningitis, GB syndrome, Transverse myelitis.iii) Others: Myocarditis, Nephritis, arthritis, hepatitis, corneal lesions, thrombocytopenia, bleeding diasthesis.* Latent infection is established in cranial nerve, sensory ganglia and spinal dorsal root ganglia. The virus may reactivate in immuno suppressive conditions, resulting in herpes zoter in about 10-30% of persons.
Latent infection
Chicken pox
Centrifugal rash
Thrombocytopenia
Virology