Question

1. The United States began including a chicken pox vaccine as part of its standard panel of childhood vaccines in 1995, and shortly after introduced a shingles vaccine for those over the age of 60. In countries that did not vaccinate against chicken pox (today, relatively few), the shingles vaccine was not necessary. Explain why this is the case. Be sure to use terms on the immune system in your response (e.g. secondary immune response, memory cells).

2. Does Flaviviruses enter the lysogenic cycle or not? Explain.

Answer 1

1. Chickenpox is found risky and particularly in newborns, pregnant woman, adults and individuals having week immune response. Shingles are painful disease which mostly affects nerves. They cause burning, shooting pain, itching or tickling and also produces rashes and blisters. They increase the risk of complications includes damage of nerves and vision.

Varicella zoster virus is found to cause both chickenpox and shingles. After getting recovered from chickenpox, the virus remains dormant in the nerves of our body. In one third of the population, the virus reappers as shingles in the later stage but not in others. Aging and/or weekend immume system again plays the role for the reappearance of the virus and the complete information is not known still.

Two primary reasons for some nantions not adopted for chickenpox vaccine:

1. It has more risk for getting chickenpox for adults than for child. There is a concern that childhood immunization will drive up the age to those who are non-immune get illness.

2. Chilhood immunization might increase the incidence of shingles which adults no longer encounter the virus.

2. Flavivirus: They are named after yellow fever virus belongs to the genus of virus family Flaviviridae. This type of virus does not enter into the lysogenic cycle.

Lysogenic cycle: It is a method where, virus replicates its DNA in the hos cell. In this cycle only dna is replicated and no translation of proteins are occured.

In the case of flavivirus, the entry into the host cells are made the attachment of the viral envelope protein E to the receptors of the host cells which in turn mediates - receptor-mediated endocytosis (RME) also clled as clathrin-mediated endocytosis. Positive stranded RNA viral transcription is the mode of transcription. Tranmission occurs by bites or from zoonosis (from animals). Humans, mosquitoes, ticks and mammals are their natural hosts.