Question

In a single (unvaccinated) family one winter, the 12-year-old and 4-year-old came down with chickenpox. The mother and father had experienced the disease as children and were unaffected this time. The 3-month-old baby did not become ill, either. However, 4 months later the baby exhibited a shingles outbreak. Using immunological phenomena, explain what was likely going on with the baby.

Answer 1

varicella is caused by vzv ,a herpes virus .it establishes latency after primary infection .usually the initial infection in upper respiratory mucosa .after 2 to 6 days virus enter circulation and viremia occures in 10 to 12 days at this time vesicle appears IgG ,IgA,IgM ANTIBODIES produced after primary infection varicella localised to sensory nerves and reactive later to produce shingles .cell mediated immunity are important in limiting duration of primary infection . if the cell mediated immunity is weaker  enough the virus enter local sensory nerves and latent in dorsal ganglion cells . the immunesystem keep the virus in check but reactivation can occur later in life

here the passive immunity child got from mother is the cause for asymptomatic or mild chicken pox in 3 month old baby this passive immunity lasts for a few weeks to 3 to4 months babies produce their own antibodies every time they exposed to virus but it will take time .neutrophils play important role in innate immunity they are the first cell that migrate in to the site of infection to begin killing the pathogen .thus neutropenia will lead to immuncompromising and latent infections may trigger.or flare up when the immunity has waned the virus dormant in dorsal root travel along the sensory nerve to produse zoster lesions on the area of skin or mucosa supplied by it .this reactivation is associated with inflammation of nerves