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Infectious Mononucleosis (Mono)

By: Ashley Gonzalez


Infectious Mononucleosis exhibits many of the same symptoms as Strep throat and other respiratory illnesses, yet it is vastly different in nature. Infectious Mononucleosis is also known as the "kissing disease," glandular fever or simply mono. This infection is most prevalent within the young adult population and peaks at ages 15-17, but also occurs within children and middle aged adults. When the prevalence of the disease is broken into different socioeconomic regions, it is found to be more prevalent within the college community, where approximately 15% of all college students are diagnosed with mono within their scholastic career.

Mono is usually caused by Epstein-Barr virus or cytomegalovirus, which are both members of the herpes family. The main route of transmission of these viruses into a host is by means of saliva or mucus transfer. This occurs by shared utensils, kissing, close range sneezing or coughing. Once the virus enters the host, it attacks the B lymphocytes in the body. The virus usually has an incubation period of 4 to 6 weeks where no symptoms are exhibited. Then the host is overcome by a series of symptoms including fever, swollen throat, enlarged spleen and lymph nodes, chronic fatigue and general body weakness. Once a person contracts mono they obtain permanent immunity due to the fact that they have antibodies to the viral antigen. The virus also remains within the epithelial tissuse of the hosts mouth and throat and can occasionaly reactivate. A person can be contagious for a period up to 18 months. There are no treatments to treating mono because it is caused by a viral infection. A person simply needs to get plenty of rest and refrain from strenuous activities.

I chose this topic because many respiratory infections have the same initial symptoms but are caused by entirely different organisms. I know many people who were misdiagnosed with strep when they in fact had mono. I was really curious to see how the two infections could be differentiated. I found that strep is caused by a bacterial infection and mono is caused by a virus. Mono also has a longer incubation period than strep does. I wanted to further research the topic in order to find the prevalence, treatments and about its contagious patterns.

What is Mono

Infectious mononucleosis is known by many different terms. It is commonly abbreviated as "mono" and referred to as the "kissing disease," or glandular fever in countries other than the United States. Mono is a viral infection characterized by fever, pharyngitis (sore throat), malaise (general body weakness), and lymphadenopathy (enlarged lymph nodes). (CDC, 2006) Mono usually occurs in individuals 10-35 years of age and its peak incidence occurs from ages 15-17. Approximately 50 people out of 100,000 in the general population get mono, but 2 out of 1,000 individuals in their teens and early twenties incur mono.

Causative Agent

Mono can be caused by one of two viruses: Epstein-Barr virus (EBV) or cytomegalovirus (CMV), both of which are members of the herpes family. 85% of mono cases are caused by EBV. (CDC, 2006) An estimated 85% to 95% of the adult population in the U.S. has EBV or CMV antibodies, which is an indication that the virus is present in their system. In other words the main causative agent of mono is EBV, but both viruses are prevalent in the adult population in the United States.
These viruses initially cause a systemic infection in the immune system of its host via replication of the viral antigen. (CDC, 2006) B lymphocytes in the epithelial lining of the mouth and throat are infected and later spread to other parts of the body including the spleen and lymph nodes.

Characteristics of Mono

Mono is a disease that is sometimes difficult to identify and detect due to its unusual characteristics. Many people who appear to be completely healthy can be carriers of mono. An estimated 50% of children 5 years of age or younger have been infected with EBV, but did not exhibit symptoms of mono or the symptoms were dismissed as a common illness. Based on this statistic it is evident that mono can be contracted even under precautions measures because the carries of mono are not always apparent.
Mono also has an incubation period of 4-6 weeks, where the host of the virus does not have any symptoms. A person can contract mono during this period as well. (Tortora, 690)

Enlarged spleen: www.wellsphere.com
Tonsils: www.faqs.org

Rash: stanford.wellsphere.com


Symptoms usually last between two weeks to four months.
  • A sore throat usually occurs for a duration lasting 7 to 10 days and is most severe for the first 3 to 5 days
  • Fever may last 10 to 14 days
  • Swollen glands may last up to 4 weeks and can be present before other symptoms occur
  • General body weakness and fatigue
Although symptoms may subside studys show that a person can be contagious for up to 18 months after the sickness has passed (webmd, 2009).

Mono is usually transferred via saliva or mucus. This transmission occurs through: kissing, coughing, sneezing, sharing utensils, dishes, toothbrushes or drinking glasses. Transmission of EBV and CMV, which cause mono do not usually occur through blood or air, although some people contract mono if they are within close range of a person who sneezes or coughs. It is recommended however that a person does not donate blood when they have mono.
Once a person contracts mono the EBV or CMV virus permanently resides in epithelial tissue, usually of the mouth and throat. A person obtains permanent immunity. Although the virus remains dormant in throat and blood it can periodically reactive. When this occurs symptoms can reoccur, but in most cases the virus become active once again for transmission to a new host. (webmd, 2009)


Diagnosis is initially decided based on symptoms a patient exhibits. Serologic tests are then conducted to confirm the diagnosis. Serologic tests for a person with infectious mononucleosis usually reveal an elevated white blood cell count, an increased percentage of certain atypical white blood cells,
and a positive reaction to a "mono spot" test. A "mono spot" test has to do with the elevated level of T cells that are responsible for killing the infected B lymphocytes. (CDC, 2006)
Paul-Bunnell heterophile antibody test can be done. If it shows up positive. A person is diagnosed with Infectious mononucleosis since the heterophile antibody is present in people with this illness. These antibodies are present within the first month and decrease after month four.
Flourescent antibody test immunoglobulin G and M, which are antibodies to viral capsid antigens. These test usually determine the stages of illness a person has.


Most importantly, the graph indicates the following:
-The antibody IgG for example persisting for life
-The antibody IgM appears within the first 4 to 6 weeks then disappears

Prevention and Treatment

There are no medications that have been proven to cure or treat all the symptoms of mono collectively. There are certain measures and medications that can be taken to alleviate certain symptoms and speed up the healing process.
  • Gargle with salt water or use throat lozenges to soothe your sore throat.
  • Acetaminophen or ibuprofen can be taken to reduce fever and relieve a sore throat and headaches
  • Steroids can be taken to target swollen throat and tonsils
  • From a nutritional standpoint, Vitamin C can be taken to speed up recovery (it is a water soluble vitamin and will flush out cells)
It is recommended that a person get plenty of rest and refrain from engaging in strenuous activity for a minimum of two weeks after symptoms have dissipated. If a person returns to daily activities too soon a relapse may occur.

Strep and mono
Both mono and strep tend to have the same symptoms, but they are very different in nature. Mono is caused by a virus and strep is caused by a bacteria, therefore only strep can be treated with antibiotics. Some doctors prescribe antibiotics to patients they think have strep when they in fact have mono. (about.com, 2007) In these cases the patient may have a temporary relief of symptoms accompanied by a rash. This rash is usually and indication of an EBV infecton not Group A Streptococci. Strep usually has a duration of 2 to 5 days whereas mono can last from 2 weeks to 4 months.

Literature Cited:

Stöppler, Melissa. "Infectious Mononucleosis (Mono)." medicinenet.com. 2009. MedicineNet. 11 May 2009 <http://www.medicinenet.com/infectious_mononucleosis/article.htm>.

Tortora, Gerard J., Berdell R. Funke, and Christine L. Case. Microbiology An Introduction with CDROM. Boston: Benjamin-Cummings Company, 2006.

Willis, Judith. "On the Teen Scene: When Mono Takes You Out of the Action." U.S. Food and Drug Administration. 1998. FDA. 11 May 2009 <http://www.fda.gov/Fdac/features/1998/398_mono.html>.

"Can you get mono and strep at the same time?." About.com. 4/2/2007. Medical review board. 10 May 2009 <http://pediatrics.about.com/od/mono/a/0307_mono_strep.htm>.

" Infectious Mononucleosis." WebMD. 12/19/2007. Healthwise. 8 May 2009 <http://www.webmd.com/a-to-z-guides/infectious-mononucleosis-what-happens>.

"National Center for Infectious Diseases Epstein-Barr Virus and Infectious Mononucleosis." Centers for Disease Control and Prevention. 5/16/2006. CDC. 9 May 2009 <http://www.cdc.gov/ncidod/diseases/ebv.htm>.