Human T-lymphotrophic virus-1 (HTLV-1)
HTLV-1 has been linked with a type of lymphocytic leukemia and non-Hodgkin lymphoma called adult T-cell leukemia/lymphoma (ATL). This cancer is found mostly in southern Japan, the Caribbean, Central Africa, parts of South America, and in some immigrant groups in the southeastern United States. In addition to ATL, the virus also causes a form of degenerative nerve disease called tropical spastic paraparesis (TSP), which is most common in Japan and in the Caribbean basin.HTLV-1 belongs to a class of viruses called retroviruses. These viruses use RNA (instead of DNA) for their genetic code. To reproduce, they must go through an extra step using an enzyme called reverse transcriptase. This allows them to change their RNA genes into DNA. Some of the new DNA genes can then become part of the chromosomes of the human cell infected by the virus. This can change the genes (cause genetic mutations) in human cells that normally control how often the cell divides. This change sometimes causes cancer. Retroviruses have long been known to cause leukemia in some animals.HTLV-1 is something like HIV, since it is another human retrovirus. But HTLV-1 cannot cause AIDS. In humans, HTLV-1 is spread in the same ways as HIV:
- Unprotected sex with an HTLV-1-infected partner
- Injection with a needle or injection equipment after an infected person has used it
- Blood transfusion from an infected donor (blood donations are now tested for this virus in developed countries)
- From infected mother to child during pregnancy, childbirth, or breastfeeding
Not everyone exposed to the virus becomes infected. For example, mothers infected with HTLV-1 have about a 10% to 30% chance of passing on the virus to their children.A survey of people coming to donate blood in several locations around the United States showed that, overall, about 1 out of every 4,000 people had HTLV-1 (about 0.025%). Around 2% to 10% of people who use intravenous drugs or who have gotten multiple transfusions become infected with HTLV-1. Screening all blood donated in the United States has greatly reduced the chance of infection through transfusion and has helped control the potential spread of HTLV-1 infection.Once infected with HTLV-1, a person's chance of developing adult T-cell lymphoma can be up to about 5%, usually after a long time with no symptoms (20 or more years). FOR MORE INFORMATION BUY THE BOOK 'MEMOIRS OF CANCER,' AND LEARN FACTS ON DIFFERENT TYPES OF CANCER AND MORE. CLICK HERE TO PURCHASE NOW AVAILABLE ON KINDLE VIA WALMART OR AMAZON AND BOOK NOOK.