suggestive of infectious mononucleosis, occurring in up to 50% of people. by blood film, one diagnostic criterion for infectious mononucleosis is the presence of 50% lymphocytes with at least 10% atypical lymphocytes (large, irregular nuclei), while the person also has fever, pharyngitis, and swollen lymph nodes. the atypical lymphocytes resembled monocytes when they were first discovered, thus the term "mononucleosis" was coined. a fibrin ring granuloma may be present. differential diagnosis about 10% of people who present a clinical picture of infectious mononucleosis do not have an acute epstein–barr-virus infection. a differential diagnosis of acute infectious mononucleosis needs to take into consideration acute cytomegalovirus infection and toxoplasma gondii infections. because their management is much the same, it is not always helpful, or possible, to distinguish between epstein–barr-virus mononucleosis and cytomegalovirus infection. however, in pregnant women, differentiation of mononucleosis from toxoplasmosis is important, since it is associated with significant consequences for the fetus. acute hiv infection can mimic signs similar to those of infectious mononucleosis, and tests should be performed for pregnant women for the same reason as toxoplasmosis. people with infectious mononucleosis are sometimes misdiagnosed with a streptococcal pharyngitis (because of the symptoms of fever, pharyngitis and adenopathy) and are given antibiotics such as ampicillin or amoxicillin as treatment. other conditions from which to distinguish infectious mononucleosis include leukemia, tonsillitis, diphtheria, common cold and influenza (flu). treatment infectious mononucleosis is generally self-limiting, so only symptomatic or supportive treatments are used. the need for rest and return to usual activities after the acute phase of the infection may reasonably be based on the person's general energy levels. nevertheless, in an effort to decrease the risk of splenic rupture experts advise avoidance of contact sports and other heavy physical activity, especially when involving increased abdominal pressure or the valsalva maneuver (as in rowing or weight training), for at least the first 3–4 weeks of illness or until enlargement of the spleen has resolved, as determined by a treating physician. medications paracetamol (acetaminophen) and nsaids, such as ibuprofen, may be used to reduce fever and pain. prednisone, a corticosteroid, while used to try to reduce throat pain or enlarged tonsils, remains controversial due to the lack of evidence that it is effective and the potential for side effects. intravenous corticosteroids, usually hydrocortisone or dexamethasone, are not recommended for routine use but may be useful if there is a risk of airway obstruction, a very low platelet count, or hemolytic anemia. antiviral agents act by inhibiting viral dna replication. there is little evidence to support the use of antivirals such as aciclovir and valacyclovir although they may reduce initial viral shedding. antivirals are expensive, risk causing resistance to antiviral agents, and (in 1% to 10% of cases) can cause unpleasant side effects. although antivirals are not recommended for people with simple infectious mononucleosis, they may be useful (in conjunction with steroids) in the management of severe ebv manifestations, such as ebv meningitis, peripheral neuritis, hepatitis, or hematologic complications. although antibiotics exert no antiviral action they may be indicated to treat bacterial secondary infections of the throat, such as with streptococcus (strep throat). however, ampicillin and amoxicillin are not recommended during acute epstein–barr virus infection as a diffuse rash may develop. observation splenomegaly is a common symptom of infectious mononucleosis and health care providers may consider using abdominal ultrasonography to get insight into the enlargement of a person's spleen. however, because spleen size varies greatly, ultrasonography is not a valid technique for assessing spleen enlargement and should not be used in typical circumstances or to make routine decisions about fitness for playing sports. prognosis serious complications are uncommon, occurring in less than 5% of cases: cns complications include meningitis, encephalitis, hemiplegia, guillain–barré syndrome, and transverse myelitis. prior infectious mononucleosis has been linked to the development of multiple sclerosis. hematologic: hemolytic anemia (direct coombs test is positive) and various cytopenias, and bleeding (caused by thrombocytopenia) can occur. mild jaundice hepatitis with the epstein–barr virus is rare. upper airway obstruction from tonsillar hypertrophy is rare. fulminant disease course of immunocompromised people are rare. splenic rupture is rare. myocarditis and pericarditis are rare. postural orthostatic tachycardia syndrome chronic fatigue syndrome cancers associated with the epstein–barr virus include burkitt's lymphoma, hodgkin's lymphoma and lymphomas in general as well as nasopharyngeal and gastric carcinoma. hemophagocytic lymphohistiocytosis once the acute symptoms of an initial infection disappear, they often do not return. but once infected, the person carries the virus for the rest of their life. the virus typically lives dormant in b lymphocytes. independent infections of mononucleosis may be contracted multiple times, regardless of whether the person is already carrying the virus dormant. periodically, the virus can reactivate, during which time the person is again infectious, but usually without any symptoms of illness. usually, a person with im has few, if any, further symptoms or problems from the latent b lymphocyte infection. however, in susceptible hosts under the appropriate environmental stressors, the virus can reactivate and cause vague physical symptoms (or may be subclinical), and during this phase, the virus can spread to others. history the characteristic symptomatology of infectious mononucleosis does not appear to have been reported until the late nineteenth century. in 1885, the renowned russian pediatrician nil filatov reported an infectious process he called "idiopathic adenitis" exhibiting symptoms that correspond to infectious mononucleosis, and in 1889 a german balneologist and pediatrician, emil pfeiffer, independently reported similar cases (some of lesser severity) that tended to cluster in families, for which he coined the term drüsenfieber ("glandular fever"). the word mononucleosis has several senses, but today it usually is used in the sense of infectious mononucleosis, which is caused by ebv. the term "infectious mononucleosis" was coined in 1920 by thomas peck sprunt and frank alexander evans in a classic clinical description of the disease published in the bulletin of the johns hopkins hospital, entitled "mononuclear leukocytosis in reaction to acute infection (infectious mononucleosis)". a lab test for infectious mononucleosis was developed in 1931 by yale school of public health professor john rodman paul and walls willard bunnell based on their discovery of heterophile antibodies in the sera of persons with the disease. the paul-bunnell test or pbt was later replaced by the heterophile antibody test. the epstein–barr virus was first identified in burkitt's lymphoma cells by michael anthony epstein and yvonne barr at the university of bristol in 1964. the link with infectious mononucleosis was uncovered in 1967 by werner and gertrude henle at the children's hospital of philadelphia, after a laboratory technician handling the virus contracted the disease: comparison of serum samples collected from the technician before and after the onset revealed development of antibodies to the virus. yale school of public health epidemiologist alfred e. evans confirmed through testing that mononucleosis was transmitted mainly through kissing, leading to it being referred to colloquially as "the kissing disease".