Not true about varicella infection:
Ans is 'c' i.e. Only single stage of lesion is present at a time The characteristic feature of chicken pox is "Pleomorphism ", that is, all stages of the rash (papules, vesicles and crusts) may be seen simultaneously at one time in the same area.Chicken poxIt occurs primarily in children <10 yrs of age.It is highly communicable by droplet infection with a secondary attack rate of approx. 90%Latent infection is established in cranial N. sensory ganglia and spinal dorsal root ganglia. The virus may reactivate in immuno-suppressive conditions, resulting in herpes zoster in about 10-30% of persons.Incubation period is 14-16 days.Period of communicability ranges from 1 to 2 days before the appearance of rash, and 4 to 5 days thereafter. Scabs are not infective.Clinical course has two stages:Pre-emptive stage - Fever, back pain, malaise for 24 hrs.Eruptive stage - In children rash is often the first sign.Distinctive features of rash are:Symmetrical, mostly on flexor surfaceSuperficialAbundant on trunk, density diminishes centrifugallyAxilla involvedSoles and palms are not involved Rapid evolution through the stages of macule, papule, vesicle (dew drop like) and scab.Scabbing begins 4-7 days after appearances of rash'Pleomorphism'Complication - hemorrhages, pneumonia, encephalitis, acute cerebellar ataxia, Reye's syndromeAcyclovir is given to prevent the development of systemic disease in varicella infected immunosuppressed patients and can halt the progression of zoster in adults.Varicella zoster immunoglobulin given within 72 hrs of exposure can prevent chicken pox and is recommended in exposed immuno compromised persons.A live attenuated varicella vaccine is recommended for children between 12-18 months. It is 90% effective even if given within 3-5 days after exposure.
Secondary attack rate if 90%
Lesions occur on flexor surfaces
Only single stage of lesion is present at a time
Reactivation occur in 10-30% cases
Communicable Diseases