The term heterophile has several definitions, depending on its use. The word itself is an alternative term for heterosexual, but its more common usage is in the medical field, where it comes up in reference to heterophile antibodies. These are antibodies produced by the immune system to fight the Epstein-Barr virus (EBV), which causes infectious mononucleosis.
Infectious mononucleosis is more commonly referred to as "mono," the "kissing disease," or glandular fever. The EBV virus is found in the saliva and mucus, and the illness is spread through the saliva or by cervical contact. This means that kissing or sharing a toothbrush, drinking glass or water bottle with an infected person can result in transmission of the virus. Infected people do not always exhibit symptoms, and the incubation period ranges from four to six weeks, which is why the spread of the condition is almost impossible to prevent.
It is mildly contagious but not often serious and can affect the liver, lymph nodes and mouth. While most sufferers of mono recover within six to eight weeks, some go on to develop a chronic form of the illness that can result in a level of fatigue and lack of energy that impacts quality of life. The virus is particularly hard on those with weakened immune systems. The more common symptoms of the EBV virus are strep throat, fever, swollen lymph nodes, headaches, nausea and vomiting.
Heterophile antibodies are produced by the body in reaction to the virus but may not be able to be detected until two or three weeks into the illness. The mono test is a quick and easy test that measures the number of antibodies in the system, but it is complicated by the fact that a small number of sufferers do not produce any antibodies at all. The antibody test will also reveal negative results after the fourth week of illness, as the number of heterophile antibodies decline. Other conditions that may show a positive result are lymphoma, systemic lupus and lupus, although none of these use the mono test as a diagnostic tool.
Once a person is infected with the EBV virus, the infection is lifelong but usually asymptomatic. The younger the patient, the milder the condition, with older patients tending to suffer more severe symptoms. The condition is most common in young adults.
