Understanding the Rise of Infectious Mononucleosis

In the back to school spirit I chose Infectious Mononucleosis as my first disease since our lab has seen a rise in cases recently. Infectious mononucleosis is cause by the Epstein Barr Virus (EBV), which is a member of the Herpes virus family. Infectious mononucleosis, often just called mono, is human (gamma) herpes virus 4. This is our first link in the chain of infection, the agent. The viruses’ reservoir is humans, where it also replicates and infects. It leaves the host or reservoir through respiratory droplets. The mode of exit, respiratory droplets, can come from saliva, drinking from other peoples drink, pre-chewing baby food and many others. Once the virus is picked up the host usually experiences a sore throat, headache, swollen tonsils

and or lymph nodes, fever, and an intense fatigue. I know that if you go to the emergency room as a teen or young adult and you mention a sore throat a rapid strep and ‘monospot’ test is ordered for the lab. The ‘monospot’ can diagnose infectious mononucleosis through an EBV antibody test. The antibody test measures the antibodies to the viral capsid antigen (VCA) and EBV nuclear antigen (EBNA). The antibody tests are used often but they will show up as positive for long time after since the virus remains latent in the host. Doctors also look at the increase in lymphocytes in a differential (exceeding 50%) and abnormalities in liver function tests, specifically aspartate aminotransferase (AST). The chain of infection is broken with fast identification in the sick, once identified they can take actions to not spread the virus. The infected and those around the infected should not share drinks. They should also use proper hand hygiene and wash toys or anything saliva from the infected may touch.
Another disease in the back to school spirits is Meningococcal disease.

Meningococcal disease is prevalent on college campuses within the resident halls; so much so that many colleges require those students that live on campus get a vaccine against it. Specifically I will look at bacterial meningitis cause by the agent Neisseria meningitidis. N. Meningitidis is found to also have humans as a reservoir. The portal of exit for the bacteria also happens to be respiratory droplets, discharge from the nose and throat. In the lab we receive many emergency room cerebral spinal fluid (CSF) samples because the patient presents with a stiff neck, and severe headache. Other common symptoms include sudden high fever, vomiting or nausea (combined with the headache), seizures, sleepiness or difficulty waking up, sensitivity to light, and confusion. The preferred method of diagnosis is recovery of the bacteria from a sterile site explicitly CSF or blood. Isolation in the CSF or blood requires a culture and usually during the cell count the bacteria can be seen among the cells, just not identified. A common course of action in the ER is to give the patient antibiotics once meningitis is suspected decreasing the chance that bacteria will be seen in the cell count or on culture. If the culture result is negative but meningitis is still suspected identification of group specific meningococcal polysaccharides in the CSF by latex agglutination is another method, however false negatives are common through this method. Polymerase chain reaction (PCR) doesn’t require any live organisms for diagnosis and it will detect the meningococcal DNA in the CSP or the plasma. Finally, the microscopic inspection of gram stained specimen could show N. Meningitidis. Breaking the chain of infection for meningitis is similar to mononucleosis and requires swift identification of the agent, and good hand hygiene. A good break in the chain for this specific agent is the vaccine offered to children and

teenagers.