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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 help fight infection.


HTLV infection is caused by a specific virus.

Risk Factors

There are two types of HTLV: HTLV-I and HTLV-II.
Factors that increase your chances of getting HTLV-I include:
  • 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 an infected mother
  • Receiving a blood transfusion or transplant in the United States 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
Factors that increase your chances of getting HTLV-II include:
  • Ethnicity: American Indian or African Pygmy
  • Being breastfed by an infected mother
  • Receiving a blood transfusion in the United States before 1988
  • Having unprotected sex with someone who is infected with the virus or who is an injection drug user
  • Injection drug use


More than 95% of people with HTLV do not have symptoms. However, having the virus puts you at higher risk of developing certain conditions.
  • If you are infected with the HTLV-I virus, it is possible that you may also develop
    • Adult T-cell leukemia (ATL). This disease involves cancer of a specific group of blood cells.
    • Opportunistic infections, including Strongyloides stercoralis hyperinfection
    • Inflammation of the eyes, joints, muscles, lungs, or skin (not common)
If you are infected with HTLV-I or HTLV-II, you 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 difficulty walking.


Your doctor will ask about your symptoms and medical history. 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 your baby.
  • Avoid unprotected sex.
  • Avoid sharing needles or syringes.


To help reduce your chance of getting the virus:
  • Avoid unprotected sex. If your partner has the virus discuss ways to prevent the spread of the virus with your doctor.
  • Avoid sharing needles or syringes.


Baylor College of Medicine https://www.bcm.edu

National Institute of Allergy and Infectious Diseases http://www.niaid.nih.gov


Health Canada http://www.hc-sc.gc.ca

Public Health Agency of Canada http://www.phac-aspc.gc.ca


Blood Systems. HTLV-I/II information sheet. United Blood Services website. Available at: http://hospitals.unitedbloodservices.org/forms/BS%5F352.pdf. Accessed February 25, 2013.

General information—HTLV. Health Protection Agency website. Available at: http://www.hpa.org.uk/web/HPAweb&Page&HPAwebAutoListName/Page/1191942172148#who. Accessed February 25, 2013.

HTLV virus. Baylor College of Medicine website. Available at: http://www.bcm.edu/molvir/index.cfm?pmid=16506. Updated July 31, 2012. Accessed February 25, 2013.

Human T-Lymphotropic Virus (HTLV). New York State Office of Alcoholism and Substance Abuse Services website. Available at: http://www.oasas.ny.gov/AdMed/FYI/HTLV-FYI.cfm. Accessed February 25, 2013.

Tropical spastic paraparesis. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed. Updated July 9, 2010. Accessed February 25, 2013.

What is HTLV-II? The National Centre for Human Retrovirology website. Available at: http://www.htlv1.eu/htlv%5Ftwo.html. Accessed February 25, 2013.

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