Mono is caused
Epstein-Barr virus (EBV).
Cytomegalovirus (CMV) causes some cases of a mono-like
illness. Much less commonly, a mono-like illness is caused by different
viruses, such as hepatitis B, rubella, and HIV. Toxoplasma gondii, a single-celled parasite, can also cause a mono-like
How mono is spread
Epstein-Barr virus (EBV) can be
found in saliva and
mucus (and sometimes tears). EBV is not spread by
casual contact. You can live in the same house with a person who has mono and
never become infected with the virus. But a person who has a weakened
immune system may be at higher risk for infectious
mono. It's possible that people who have had mono can spread the virus even
though they no longer have symptoms.
- EBV lives and grows in the nose and throat.
Any fluid that comes from these parts of the body, including saliva, tears, or
mucus, can be infected with the virus. The virus (EBV) is spread when people
come in contact with infected fluids.
- EBV can be spread through
intimate contact or sharing of saliva. (A brief kiss on the lips is not likely
to spread EBV. It is spread when saliva from an infected person gets into
another person's mouth.)
- You can get EBV if you share a drinking
glass or eating utensils with an infected person (through sharing
- In rare cases, someone can get an infection after
receiving blood from a person who is infected with EBV.
- Most people
get infected with EBV at some point in their lives but never get mono symptoms.
EBV "sleeps" (is dormant) in the body. It can become active from time to time
and spread to others. When it reactivates, most people do not have symptoms.
Many healthy people carry the virus and spread it every now and then throughout
their lives. Lifetime carriers of EBV are the most common source of EBV
Contagious and incubation period
- You can pass the Epstein-Barr virus (EBV) to
others for several weeks or months during and after the time you are first
infected with EBV. The virus can also become active and spread to others from
time to time throughout your life.
- There is a small risk of spreading EBV through blood products.
If you know you have mono, you should not donate blood.
- It takes 4
to 6 weeks for symptoms to develop after you come in contact with EBV. This is
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