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Human T cell Lymphotropic Viral Infection

  • Cynthia M. Johnson, MA
Publication Type:


Human T cell Lymphotropic Viral Infection



Human T cell lymphotropic virus (HTLV) infects a type of white blood cell called a T-cell or T-lymphocyte. White blood cells are a type of cell that helps fight infection.

HTLV is a type of retrovirus that can cause cancer. It is different than the retrovirus that causes AIDS .


HTLV infection is caused by a specific virus.


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Risk Factors

There are two types of HTLV: HTLV-I and HTLV-II.

Things that may raise the risk of getting HTLV-I are:

  • Living in an area where the virus is common, such as Southern Japan, Caribbean countries, parts of Africa and South America, the Middle East, and Melanesia
  • Being breastfed by someone who has the infection
  • Getting a blood transfusion or transplant in the US before 1988
  • Having unprotected sex with someone who is infected with the virus, who is an injection drug user, or who is from an area where the virus is common
  • Injection drug use

People of American Indian or African Pygmy descent are at greater risk for HTLV-II.

Things that may that raise the risk of getting HTLV-II are:

  • Being breastfed by an infected mother
  • Getting a blood transfusion in the US before 1988
  • Having unprotected sex with someone who is infected with the virus or who is an injection drug user
  • Injection drug use


Most people with HTLV do not have symptoms, but having the virus puts people at higher risk of certain health problems.

People with HTLV-1 may develop:

  • Adult T-cell leukemia (ATL). This disease involves cancer of a specific group of white blood cells.
  • Opportunistic infections, including Strongyloides stercoralis hyperinfection
  • Inflammation of the eyes, joints, muscles, lungs, or skin (rare)

A person infected with HTLV-I or HTLV-II, may also develop a disorder of the nervous system known as HTLV-associated myelopathy/tropical spastic paraparesis (HAM/TSP). It can cause weakness, numbness and stiffness in the legs, and problems walking.


The doctor will ask about symptoms and past health. A physical exam will be done.

HTLV infection can only be diagnosed with a specific blood test. The presence of HTLV antibodies is a sign of infection with the virus.


There is no treatment that can remove the virus from the body. Treatment is aimed at managing HTLV-associated diseases and reducing their symptoms.

To prevent spreading HTLV to others:

  • Do not donate plasma, bone marrow, organs, semen, or breast milk.
  • Do not breastfeed.
  • Avoid unprotected sex.
  • Avoid sharing needles or syringes.


To lower the risk of HTLV infection:

  • Avoid unprotected sex.
  • Do not share needles or syringes.




  • Human T-cell lymphotropic virus type 1 (HTLV-1). EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/human-t-cell-lymphotropic-virus-type-1-htlv-1.
  • Human T-lymphotropic virus (HTLV). New York State Office of Alcoholism and Substance Abuse Services website. Available at: https://oasas.ny.gov/AdMed/FYI/HTLV-FYI.cfm.


  • David L. Horn, MD, FACP
Last Updated:

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.