Why Is There No Immunity After Parasitic Infection?

[Raghav Gupta]

Homework Statement

An individual suffered from a severe bout of parasitic infection. He recovered from this illness using some medical help, however he is affected by the same allergy in the next season of infection. The doctors are perplexed and would like to understand why the person is unable to display any immunity to the parasite. What can be the possible cause for the condition displayed by the individual?

Homework Equations

Don't know.

The Attempt at a Solution

Is it the parasite has modified and macrophages are not able to detect this? But here in question it is mentioned that individual is affected by same allergy.

 

[galadriel3562]

Would it be possible to get more details on the question?

With this I can only give a very general response: immunity to parasites is somewhat different from immunity responses to bacteria and/or viruses as parasites can be a great deal larger than the average white blood cell (think intestinal parasite such as worms which can grow to be meters in length) where as some parasites are small enough to exist within human cells. In general parasites don't mutate much - certainly not as much or as quickly as viruses do - so it's unlikely that a change in the parasite itself caused the patient trouble. But there are often many subspecies of a particular parasite which may led to re-infection with a different subtype. Additionally some parasites have latent stages in their lifecycle, where in a patient doesn't have any symptoms and may appear to be fine, until the parasite enters a new stage and becomes active once more. It might be that the initial infection was never fully cleared and the patient is suffering from activation of a dormant parasite.

Further more I'm a little confused by the term allergy in your question. Immunity responses to parasites are not called 'allergies' however there is some data on the fact that a prior parasitic infection might trigger an auto-immune response in humans, which can sometimes be confused with allergies?