What is a Latent Infection?

A latent infection is a situation in which a virus is present in the body, but it remains dormant.
Herpes simplex, which often causes cold sores, is a type of latent infection.
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  • Written By: Mary McMahon
  • Edited By: O. Wallace
  • Last Modified Date: 09 November 2014
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A latent infection is a situation in which a virus is present in the body, but it remains dormant, not causing any overt symptoms. The patient is still infected with the virus, and he or she can pass the virus on to others when they are exposed to the dormant virus. Latent infections can also be activated, causing symptoms and illness to emerge again. A classic example of a latent infection is herpes simplex, which periodically flares up to cause cold sores before going dormant again.

People sometimes confuse latent infections with latency. Latency or clinical latency is one of the things which occurs during the incubation period of an infection, in which the causative agent is present in the body and multiplying, but not causing symptoms. The virus involved in clinical latency is not dormant, as is the case with latent infections, but fully active and causing problems for the host organism. Eventually, the virus will move out of latency and start causing detectable symptoms, alerting the host to the fact that an infection is occurring.

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Some infections can never be fully flushed from the body, becoming latent with the use of medications and other measures to control the virus and inhibit replication. In these cases, the latent infection may periodically flare up in response to environmental cues. Latent infections can also be caused when a virus mutates, becoming impossible to eradicate, or when a course of treatment is not completed, allowing a virus to remain dormant in the body.

A number of viruses are characterized by causing latent infection, allowing the virus to ebb and flow in the body in cycles as the environment changes. From the point of view of the virus, the ability to go dormant is critical, as it allows the virus to retain a host while becoming dormant when conditions are hostile or unpleasant for the virus. Latent infections can also be very hard to detect, or to manage.

In addition to causing problems for the host by periodically flaring up and causing an array of symptoms, latent infections can become more sinister. Several viruses have been linked with out of control cell division, which is presumably caused by a scrambling of the viral and cell DNA which leads to crossed wires and rampant division of the cell. Latent infections can also become a serious problem when a patient becomes immunocompromised, as the latent infection may manifest when the patient's immune system passes a critical point.

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Discuss this Article

jellies
Post 3

This really scares me that a virus could stay latent in a body for so long -- especially if there are some you can't ever get rid of!

So do people with latent viruses just have to keep a lot of medicine on hand all the time in case they get a flare up, or what do they do?

It sounds like it would be a very annoying situation at best, and really dangerous at worst.

SalmonRiver
Post 2

Is malaria considered a latent infection? I have heard that it can come back again and again over a person's lifetime, so it would seem like it would be. Can anybody clear this up for me? I need to know because I have a paper due on this for my biology class next week, so any help would be much appreciated!

Andras
Post 1

Another type of herpes infection that goes latent is herpes varicella, or chicken pox -- I know because I had a case go latent on me for a really long time, and then come back as shingles!

I was so shocked, because according to my doctor, the virus had been latent for years before it finally reactivated. Kind of scary how something like that can live in your body for so long...

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