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which virus has such a high incidence of genetic drift that more than one antigenic variant can be isolated from most infected individuals?




4-influenza virus


answer given is HIV

why also influenza can not be correct? we have genetic drift(beside sifting) in influenza which is responsible for epidemic influenza.


Yes, I agree with you. I think I saw this question in Kaplan book itself. Influenza is right answer too. Basically, the question is a sub-standard one and Kaplan does that too often. DOnt worrry !!

On Jun 27, 2010 - 12:25 PM, doctorforever responded:


HIV is the right answer. All viruses can potentially undergo antigenic drift, except Polio (one of the reasons why Polio vaccine is so effective).

But, HIV is famously known for its antigenic drift b/c HIV is piss-poor at proofreading.

Influenza is mostly known for its antigenic shift.


I wonder if question asked which organism is famous for what. And influenza is big time wellknown org for both - shift and drift. It's just a poor question. No offense meant. Just wanted to clarify.


HIV is the only virus that infects one person, mutate extensively in that person, then show up as multiple strains later on in that very same person - i.e. show up as more than one antigenic variant in the very same patient.


thanks guys.

i just think it is not a well designed question ,in my idea both should be considered for Ag drift


ya... HIV is absolutely correct as the question asked is about getting multiple types of viruses from same patient...
In case of influenza, its during transmission that the drift occurs....hence you find only one type of organism in 1 patient


high incidence ( inluenza v.)with seasonal variation(with in one year),,,,,while HIV it take 10 years duration,,,,,,so when duration is high the incidence will be low and in Q he said(most infected indivduals-group not single),,, influ. vi. is the answer
note,,incedence=no. of newcases/duration

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