Cancer is the most dangerous disease in the world. A disease that is caused due to uncontrolled cell division and can spread out through your whole body is called cancer. Its signs and symptoms can be varying to a wide extent. The general signs and symptoms of the cancer are Fatigue, Weight changes (loss or gain both) Persistent cough, skin changes, such as darkening or redness and yellowing of the skin, Lump that can be felt under the skin, Unexplained bleeding or bruising, Hoarseness, unexplained fevers or night sweats, indigestion or discomfort after eating and unexplained muscle or joint pain, etc.
Viruses
Viruses are small organisms that can or sometimes cannot be seen under an ordinary microscope. These viruses are made up of a number of genes in the form of RNA or DNA that are surrounded by a protein coating. A virus can enter a living cell and can reproduce itself in a large number. Some of the viruses multiply themselves by inserting their RNA or DNA into the host cell of living beings. When the RNA or DNA affects the hosts, it can lead to the development of cancer.
Viruses that can cause Cancer
- Human papilloma viruses (HPVs)
- Human immunodeficiency virus (HIV)
- Epstein-Barr virus (EBV)
- Human herpes virus 8 (HHV-8)
- Human T-lymphotropic virus-1 (HTLV-1)
- Hepatitis B virus (HBV) and hepatitis C virus (HCV)
- Merkel cell polyomavirus (MCV)
Human papilloma viruses (HPVs)
- They are a group of more than 150 related viruses.
- They are commonly known as Human papillomavirus because some of them cause papillomas, which are commonly known as warts.
- This HPV can grow in the skin, throat, mouth, or vagina.
- It can spread through-Touch and Sexual contact.
- Some people having long-lasting HPV can lead to a high risk of developing cancer.
- There are no symptoms of this HPV infection.
- There is no effective treatment or medicine for HPV other than you have to destroy or remove the cells that are infected with HPV.
- Types of cancer caused by this HPV are
- Cervical cancer
- Penile cancer
- Anal cancer
- Oral cavity and oropharyngeal cancers
- Vaginal cancer
- Vulval cancer
- Vaccines are available for this infection as a series of injections. These are available for children, young ones, and adults including males and females.
- These vaccines didn’t stop or prevent the existing infections, but they prevent the infections that are caused by HPV.
Human immunodeficiency virus (HIV)
- This virus doesn’t cause cancer directly, but this HIV virus can lead a person in risk of several types of cancer.
- HIV causes AIDS (acquired immune deficiency syndrome).
- This virus spreads through
- Having unprotected sex with an HIV-infected person.
- Use of injection equipment or injections that is already used by an HIV-infected person.
- Breastfeeding from an HIV-infected mother.
- Transplanting of organs from an HIV-infected person.
- Transfusion of blood from an HIV-infected person.
- HIV doesn’t spread through water, insect, or casual contact such as hugging, sharing dishes, coughing, shaking hands, phones and kitchens, etc.
- This HIV destroys or infects the white blood cells known as helper T cells that weaken the immune system of the body. This can be a way for other viruses(HPV, thrive) to enter the body to cause cancer.
- Types of cancer that develop in an HIV-infected person:
- Cervical cancer
- Anal cancer
- Lung cancer
- Kaposi sarcoma
- Hodgkin’s disease
- Cancer of the throat and mouth
- Liver cancer
- Skin cancer
- HIV has no symptoms at all. You can have a test as a general health care routine to test whether you are positive or not for HIV.
- HIV has no vaccine for prevention, but you can prevent it by protected sex with an HIV-infected person. Not sharing needles and other equipment with HIV-infected persons. High-risk patients of HIV can take injection drugs or medicines (pills) to lower the risks of HIV.
- HIV-positive patients can take anti-HIV drugs just as a precaution so that other viruses don’t affect them.
Epstein-Barr virus (EBV)
- It is a type of herpes virus.
- It causes infectious mononucleosis, also called “mono” or the “kissing diseases”.
- Furthermore, it can be spread through:
- kissing
- coughing
- sharing drinks
- sharing utensils
- sneezing.
- It’s a lifelong infection.
- It has no symptoms, and it impacts certain white blood cells in the body called B lymphocytes.
- There is no medicine or treatment for the infection that is caused by EBV.
- There are also no treatments or medicine for the prevention of this EBV.
- EBV doesn’t cause serious problems in most people.
- Type of cancer that is developed by EBV are:
- Stomach cancer
- Nasopharyngeal cancer
- Burkitt lymphoma
- Hodgkin lymphoma
- Very few people are impacted by this EBV.
Human herpes virus 8 (HHV-8)
- It is also known as Kaposi sarcoma-associated herpes virus (KSHV).
- It is found in patients who are suffering from Kaposi sarcoma (KS).
- KS is a slow-growing and rare cancer that often appears as blue-brown or reddish-purple tumors just underneath the skin.
- In KS, lymph vessels and bloodline cells are infected by HHV-8.
- Eventually, these changes in the body lead to the development of cancer.
- It can be spread through saliva, blood, and sex.
- It’s a lifelong virus (as EBV) but doesn’t cause serious problems for healthy persons.
- This KS mainly attacks people who have weakened the immune systems.
- It causes some rare blood cancers: primary effusion lymphoma.
Human T-lymphotropic virus-1 (HTLV-1)
- This HTLV-1 is linked with a type of non-Hodgkin lymphoma called adult T-cell leukemia/lymphoma (ATL) and lymphocyte leukemia.
- It belongs to the retroviruses class of virus.
- This virus spreads through
- Having unprotected sex with an HTLV-1 infected person.
- Use of injection equipment or injections that is already used by an HTLV-1 infected person.
- Breastfeeding from an HTLV-1 infected mother.
- Transplanting of organs from an HTLV-1 infected person.
- Transfusion of blood from an HTLV-1 infected person.
- There are no symptoms of HTLV-1.
- These viruses use RNA as their genetic code. To reproduce themselves, they have to go through an extra stage to change their RNA genes into DNA. Now, the new DNA genes will become the part of chromosomes of human cells infected by the HTLV-1. This leads to a change in how a cell divides and grows, which results in the development of cancer.
Hepatitis B virus (HBV) and hepatitis C virus (HCV)
- HCV and HBV cause viral hepatitis (type of liver infection).
- This virus spreads through
- Having unprotected sex with an HTLV-1 infected person.
- Use of injection equipment or injections that is already used by an HTLV-1 infected person.
- Breastfeeding from an HTLV-1 infected mother.
- Transplanting of organs from an HTLV-1 infected person.
- Transfusion of blood from an HTLV-1 infected person.
- Symptoms of HBV are
- Jaundice (yellowing of skin and eyes)
- Flu-like illness
- People who are suffering from chronic HBV have a higher risk for liver cancer.
- HCV has no symptoms. It can only be identified by having tests.
- Both HCV and HBV can be treated with drugs that slow down liver damage and reduce the risk of cancer.
- Chronic hepatitis C infection is one that can’t be treated with a couple of drugs.
- There is a vaccine available for HBV, but not for HCV.
Merkel cell polyomavirus (MCP)
- It was discovered from a rare type of skin cancer called Merkel cell carcinoma.
- It has no symptoms at all.
- The spreaders of this virus are still unknown.
- In a few peoples, this infection cause effect the DNA, which develops Merkel cell cancer.
Conceptual Question
Question 1: Write general signs and symptoms of cancer?
Answer:
General signs and symptoms are Fatigue, Weight changes (loss or gain both), Persistent cough, and Skin changes, such as darkening or redness and yellowing of the skin
Question 2: Name the types of cancer that are caused by Human papillomaviruses (HPV)?
Answer:
Types of cancer caused by this HPV are :
- Cervical cancer
- Penile cancer
- Anal cancer
- Oral cavity and oropharynxes cancers
- Vaginal cancer
- Vulval cancer
Question 3: How does HIV spread from one person to another?
Answer:
This Human immunodeficiency virus spreads through :
- Having unprotected sex with an HIV-infected person.
- Use of injection equipment or injections that is already used by an HIV-infected person.
- Breastfeeding from an HIV-infected mother.
- Transplanting of organs from an HIV-infected person.
- Transfusion of blood from an HIV-infected person.
Question 4: Write about Kaposi sarcoma–associated herpes virus?
Answer:
KS is a slow-growing and rare cancer that often appears as blue-brown or reddish-purple tumors just underneath the skin. In KS, lymph vessels and bloodline cells are infected by HHV-8. Eventually, these changes in the body lead to the development of cancer. It can be spread through saliva, blood, and sex. It’s a lifelong virus (as EBV) but doesn’t cause serious problems for healthy persons. This KS mainly attacks people who have weakened the immune systems. It causes some rare blood cancers: primary effusion lymphoma.
Question 5: Which virus belongs to the Retrovirus class of virus?
Answer:
Human T-lymphotrophic virus-1 (HTLV-1)