What is a Latent Infection?

Mary McMahon
Mary McMahon
Mary McMahon
Mary McMahon
A person with a latent infection can still pass the virus on to others.
A person with a latent infection can still pass the virus on to others.

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.

Herpes simplex, which often causes cold sores, is a type of latent infection.
Herpes simplex, which often causes cold sores, is a type of latent infection.

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 these 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.

A latent infection is a situation in which a virus is present in the body, but it remains dormant.
A latent infection is a situation in which a virus is present in the body, but it remains dormant.

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 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.

Some infections are never fully flushed from the body and become latent.
Some infections are never fully flushed from the body and become latent.

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. These infections can also be very hard to detect, or to manage.

Fever is a potential warning sign of an infection.
Fever is a potential warning sign of an infection.

In addition to causing problems for the host by periodically flaring up and causing an array of symptoms, these 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 infection may manifest when the patient's immune system passes a critical point.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a wiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a wiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

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Discussion Comments

jellies

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

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

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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    • A person with a latent infection can still pass the virus on to others.
      A person with a latent infection can still pass the virus on to others.
    • Herpes simplex, which often causes cold sores, is a type of latent infection.
      Herpes simplex, which often causes cold sores, is a type of latent infection.
    • A latent infection is a situation in which a virus is present in the body, but it remains dormant.
      A latent infection is a situation in which a virus is present in the body, but it remains dormant.
    • Some infections are never fully flushed from the body and become latent.
      Some infections are never fully flushed from the body and become latent.
    • Fever is a potential warning sign of an infection.
      Fever is a potential warning sign of an infection.