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Other viruses

  • Epstein-Barr virus (EBV)

    Epstein-Barr virus (EBV) is a common type of herpes virus. It is one of the most common viruses in humans, affecting more than 90% of people in the world before the age of 20. This virus causes infectious mononucleosis (mono or the “kissing disease”). EBV infects and stays in certain white blood cells in the body called lymphocytes, particularly B lymphocytes (B cells). EBV can also infect T lymphocytes (T cells) or epithelial cells.

    Infection with EBV usually occurs in childhood. Most people develop only mild or no symptoms. Symptoms of mono include fever, sore throat and swollen lymph nodes.

    EBV stays in the body throughout life, though most people do not have any symptoms after the first few weeks of infection.

    Exposure

    The EBV is present in saliva, so it is mainly spread by oral contact. It can be passed from person-to-person by kissing, sharing drinking or eating utensils and by coughing or sneezing.

    People who have immunosuppression have lower immunity against various persistent infections, including EBV. People can have immunosuppression from taking immune-suppressing drugs to prevent rejection of a transplanted organ or having AIDS.

    EBV and cancer 

    In certain cases, long-term infection with EBV can increase the risk of developing certain types of cancer, including:

    •  some types of non-Hodgkin lymphoma (such as Burkitt lymphoma and post-transplant lymphoproliferative disorder)
    • Hodgkin lymphoma
    • nasopharyngeal cancer
    • some types of stomach (gastric) cancer

    Most of these cancers are more common in Africa and parts of Southeast Asia. Generally, very few people infected with EBV develop these cancers, so other risk factors (cofactors) likely play a part in cancer development.

    How to test for EBV

    A blood test can also be done to check for antibodies to the Epstein-Barr virus to find out if a person has been infected with EBV.

    Reducing your risk

    At this time, there is no vaccine that prevents EBV infection. To help reduce the risk of EBV infection, do not share drinks, food, eating and drinking utensils or toothbrushes. 

  • Human herpes virus 8 (HHV8)

    Human herpes virus 8 (HHV8) is found in nearly all Kaposi sarcoma (KS) tumours. HHV8 is also called Kaposi sarcoma herpes virus (KSHV). HHV8 is related to other herpes viruses, which cause cold sores, mononucleosis and chicken pox. Although HHV8 remains in the body after infection, the immune system usually keeps the virus in check. Most people with HHV8 infection don’t have symptoms.

    HHV8 infection is not very common in North American countries. It occurs more frequently in some Mediterranean countries and is widespread in Africa.

    Exposure

    HHV8 is spread mainly through sexual contact. It may also be spread through blood and saliva. HHV8 does not appear to cause disease in most healthy people. People who develop KS usually have other health problems that weaken their immune system, such as:

    •  AIDS (acquired immune deficiency syndrome)
    • taking immune-suppressing drugs (for example, after an organ transplant)
    • blood diseases like Castleman disease (an uncommon disease that acts like lymphoma)

    HHV8 and cancer

    Kaposi sarcoma is a rare type of cancer that develops in the cells that line the lymph or blood vessels. HHV8 infection turns these cells into cancer cells, which multiply and grow into nearby tissues. KS often appears as purplish patches just underneath the skin, but the patches can range in colour.

    HHV8 infection has also been linked to some other rare cancers, such as primary effusion lymphoma.

    How to test for HHV8 

    A blood test can also be done to check for antibodies to HHV8. KS tumours can also be tested for HHV8.

    Reducing your risk 

    At this time, there is no vaccine that prevents HHV8 infection. To help reduce your risk of HHV8 infection, avoid behaviours that increase the risk of HIV (human immunodeficiency virus) infection, the virus that causes AIDS.

    •  If you are sexually active, practise safe sex. Use a condom to help protect against HHV8 and HIV, as well as other sexually transmitted infections.

    People with a weakened immune system may be given antiherpes virus drugs to keep the HHV8 virus from multiplying. However, researchers are still studying the effectiveness of antiviral drugs.

  • Human immunodeficiency virus (HIV)

    The human immunodeficiency virus (HIV) is a retrovirus. A retrovirus is a type of virus that uses RNA (instead of DNA) for its genetic material. Retroviruses use a special enzyme to multiply, which allows them to change their RNA into DNA. The new DNA is then inserted into the DNA of the infected cell, which allows the virus to multiply every time the infected cell reproduces.

    HIV infects a type of white blood cell called a helper T cell or CD4 cell. The virus can cause acquired immune deficiency syndrome (AIDS), a disease in which lymphocytes are destroyed and the body cannot protect itself from infections. Most cases of AIDS worldwide are the result of HIV infection.

    Many people with HIV infection don’t get sick for many years. They are treated with anti-HIV drugs called highly active antiretroviral therapy (HAART). HAART controls the virus and allows the immune system to rebuild itself. However, as HIV disease progresses, it slowly wears down the immune system. As the immune system weakens, the person can develop AIDS.

    People with HIV infection have a much higher risk of some types of cancer compared to people who are not infected.

    Exposure

    HIV can spread from an infected person to someone else in the following ways:

    •  by having unprotected sex (oral, vaginal or anal)
    • by sharing needles, syringes or other equipment for injecting drugs
    • through a transfusion with contaminated blood or blood products
      • Canadian Blood Services tests every blood donation for HIV. Only blood that does not contain this virus is used, so the risk of getting an HIV infection through a blood transfusion is very low.
    • from an infected mother to a child during pregnancy, at birth or through breastfeeding
    • if healthcare workers accidently get a needle stick or sharp equipment injury while caring for someone with HIV infection
    • having an organ transplant from an HIV-infected person
      • Organ donors are tested for HIV.

    HIV is not spread by casual contact, such as talking, shaking hands, hugging, coughing or sneezing.

    HIV infection and cancer 

    HIV does not appear to cause cancers directly. HIV infection weakens the immune system, so the body cannot fight infections and diseases as well. This can contribute to the development of cancer. Also, people infected with HIV may have a higher risk of some cancers compared with the general population in part because of the higher incidence of other risk factors, such as smoking, alcohol use and infection with other cancer-causing viruses like HHV8 and HPV.

    There is sufficient evidence that HIV infection increases the risk of:

    •  Kaposi sarcoma
    • anal cancer
    • certain types of non-Hodgkin lymphoma
    • Hodgkin lymphoma
    • cervical cancer
    • cancer of the conjunctiva (a thin membrane that lines the inner surface of the eyelids and the outer surface of the eye)

    Other cancers may develop in people whose immune system is weakened because of HIV infection, including:

    • some types of skin cancer
    • reproductive cancers, such as vaginal, vulvar, penile and testicular cancer
    • lung cancer
    • liver cancer
    • cancer of the mouth and throat

    HAART has improved survival of people with HIV infection. HAART has also reduced the incidence of several diseases associated with HIV infection, including some types of cancer.

    How to test for HIV

    If you think you are at risk for HIV infection or have been exposed to HIV, talk to your healthcare provider about getting tested. A blood test is usually done to see if you have been exposed to the virus. People who have the HIV antibodies are said to be HIV-positive.

    If you are pregnant and concerned about HIV, talk to your doctor about being tested. Early treatment with medication can prevent HIV from being spread from a mother to her baby before birth. 

    Reducing your risk

    At this time, there is no vaccine that prevents HIV infection. To help reduce your risk for HIV infection: 

    • Practise safe sex.
      • Use a condom to help protect against HIV infection, as well as other sexually transmitted infections.
    • Do not share any needles, syringes or other drug use equipment.
    • Do not share personal care articles, such as razors, scissors, nail clippers or toothbrush with an infected person.
    • Wear latex gloves when you come into contact with someone else’s blood or body fluids.
  • Human T-cell leukemia/lymphoma virus (HTLV)

    Human T-cell leukemia/lymphoma virus (HTLV) is a retrovirus. A retrovirus is a type of virus that uses RNA (instead of DNA) for its genetic material. Retroviruses use a special enzyme to multiply, which allows them to change their RNA into DNA. The new DNA is then inserted into the DNA of the infected cell, which allows the virus to multiply every time the infected cell reproduces. Human T-cell leukemia/lymphoma virus is also called human T-cell lymphotropic virus.

    The HTLV associated with cancer is called human T-cell leukemia/lymphoma virus type 1 (HTLV-1). This virus infects a type of white blood cell called a T cell. HTLV-1 is similar to HIV, another retrovirus, but HTLV-1 doesn’t cause AIDS.

    Once infected with HTLV-1, a person carries the infection for life. In many cases, people carrying the virus do not get symptoms or develop health problems from it.

    Exposure

    HTLV-1 is spread in much the same way as HIV. It can be spread from a person infected with HTLV-1 to someone else:

    •  by having unprotected sex
    • by sharing needles, syringes or other equipment for injecting drugs
    • through a transfusion with contaminated blood or blood products
      • Canadian Blood Services tests every blood donation for HTLV-1. Only blood that does not contain this virus is used, so the risk of getting an HTLV-1 infection through a blood transfusion is very low.
    • from an infected mother to a child during birth or through breastfeeding
      • Mothers infected with HTLV-1 have a 10%–30% chance of passing the virus on to their children. The risk is reduced if the mother doesn’t breastfeed.

     Not everyone exposed to HTLV-1 becomes infected.

    HTLV-1 and cancer

    HTLV-1 can cause an uncommon type of T-cell lymphocytic leukemia and non-Hodgkin lymphoma in adults called adult T-cell leukemia/lymphoma (ATL/L). This cancer is not common in Canada and occurs mostly in Japan and the Caribbean.

    People who carry the HTLV-1 have a 2%–4% lifetime risk of developing ATL/L. It often takes a very long time before the person infected with the virus develops ATL/L. However, only a few people who have HTLV-1 will develop ATL/L. 

    How to test for HTLV-1 

    A blood test can be done to check for antibodies to the virus.

    Reducing your risk

    At this time, there is no vaccine that prevents HTLV-1 infection. To help reduce your risk of HTLV-1 infection:

    • Practise safe sex
      • Use a condom to help protect against the HTLV-1, as well as other sexually transmitted infections.
    • Do not share any needles, syringes or other drug use equipment

    There is no treatment to get rid of the virus once you are infected.

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