Arenaviruses Clinical Presentation

Updated: Oct 05, 2015
  • Author: Sandra G Gompf, MD, FACP, FIDSA; Chief Editor: Pranatharthi Haran Chandrasekar, MBBS, MD  more...
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Clinically apparent arenavirus infections typically present with fever, headache, myalgia, and malaise. Relative bradycardia and hyperesthesia are common as well. Thereafter, the various diseases pursue different courses as follows:

Lymphocytic choriomeningitis virus

This usually benign infection generally begins with fever, myalgia, and headache. Leukopenia and thrombocytopenia are revealed on laboratory studies.

The illness can be biphasic.

The second febrile period and some of the late complications (see Complications) may be immunologic in origin.

Lassa fever

Most infections due to the Lassa virus are mild or subclinical.

Severe multisystem disease is believed to occur in 5-10% of total infections.

Incubation period is 7-18 days.

Illness begins insidiously with fever, weakness, malaise, joint and/or lumbar pain, cough, and severe headache.

In severe cases, illness progresses to include prostration, dehydration, abdominal pain, and facial or neck edema. Serum aminotransferases may be elevated. Note that Lassa fever stands alone among causes of viral hepatitis to have aspartate aminotransferase (AST) levels substantially higher than alanine aminotransferase (ALT) levels. This pattern has been classic for alcoholic hepatitis.

Lymphopenia, thrombocytopenia, and defects of qualitative platelet function are found during this stage.

South American hemorrhagic fevers

Junin and Machupo viruses are similar in severity, and anecdotal reports suggest that Guanarito infections may be somewhat more severe overall.

The illnesses begin somewhat insidiously with fever, malaise, myalgia, and lumbar pain.

Progression may occur over 3-4 days, with prostration, unremitting fever, and mucosal bleeding. Hemorrhage along the gingival margins is characteristic.

After 1-2 weeks, most patients improve, but approximately one third progress to profound cutaneous and mucosal hemorrhages, delirium, and convulsions or a combination of CNS and bleeding findings. Capillary leak syndrome also may occur.



The major physical examination findings observed in the major Arenavirus illnesses are as follows:

Lymphocytic choriomeningitis virus

Conjunctival injection, facial flushing, generalized lymphadenopathy, and orthostatic hypotension are common.

Fever and more severe headaches may recur 2-4 days after recovery from the first phase, with overt lymphocytic pleocytotic meningitis with elevated cerebrospinal (CSF) protein. Papilledema may be noted.

Lassa fever

Pharyngitis, often exudative, occurs early. Conjunctivitis also may be seen.

Later, in severe disease, CNS signs can be seen, including tremors, confusion, encephalopathy, and seizures. Focal CNS signs usually are absent, and CSF is normal.

Bleeding is seen in only 15-20% of patients, it usually is limited to mucosal surfaces, and it is limited in severity.

South American hemorrhagic fever

Conjunctival injection, facial flushing, generalized lymphadenopathy, and orthostatic hypotension are common signs.

Many patients have a petechial and/or vesicular palatal enanthem and skin petechiae.

At the point of further progression, CNS signs can include tremor of hands and tongue, hyperesthesias, decreased deep-tendon reflexes, and lethargy.

Especially with deteriorating illness, leukopenia and thrombocytopenia are common but aminotransferase elevations are uncommon.