Table 2.

Arenaviral hemorrhagic fevers pathological characteristics. The name of the disease (when existing), along with the prin-cipal clinical symptoms caused by Old World Arenaviruses and New World Arenaviruses are briefly explained. Modified from [13]

Agent (Disease)	Pathological Characteristics
Old World Lassa (Lassa Fever)	Incubation: 3 to 21 days. Fever, headache, myalgia, backache, trembling and sickness. Generalized infection: hemorrhagic dissemination of virus to several organs and systems via bloodstream, lymphatic system, respiratory and digestive tract. Black vomit, aqueous diarrhea (dehydration), quantity decrease of lymphocytes and platelets, mild thrombocytopenia, abdominal, pleuritic and hepatic pain. Extensive reticulo-endothelial compromise: capillary injuries causing stomach, small intestine, kidney, lung and brain bleeding. Multifocal hepatocellular necrosis with Councilman-like bodies, hepatocytes cytoplasmic degeneration and minimal inflammatory response. Adrenal focal necrosis and cytoplasmic inclusions. Respiratory system: interstitial pneumonia, cough, dyspnea, bronchitis, pneumonia and pleurisy. Cardiovascular system: pericarditis, tachycardia, bradycardia, hypertension, hypotension, thrombocytopenia, leukopenia and hiperuricemia, lymphadenopathy, elevated aminotransferases, decreased prothrombin level, disorder of blood circulation and bleeding through the skin, lungs, gastrointestinal tract and other mucosa membranes. Nervous system: encephalitis, meningitis, uni- or bilateral hearing decrease, convulsions.
New World Junín (Argentine Hemorrhagic Fever) Machupo and Chapare (Bolivian Hemorrhagic Fever) Guanarito (Venezuelan Hemorrhagic Fever) Sabiá (Brazilian Hemorrhagic Fever) Whitewater Arroyo Flexal Lujo	Incubation: 6 to 14 days. First 4 days: decaying, fever, anorexia, nausea and vomiting, headache and myalgia. Second stage: acute hemorrhagic syndrome (epistaxis and hematemesis), or acute neurologic syndrome. General: malaise, high fever, severe myalgia, anorexia, back pain, abdominal tenderness, conjunctivitis, retro-orbital pain, photophobia, and usually constipation. Acute phase of infection: peripheral blood viral active replication. Oropharyngeal enanthem. Gums swollen, congested and bleeding (gingival border). Proteinuria high dehydration and hemoconcentration. In women, early menorrhagia. Multifocal hepatocellular necrosis with formation of Councilman-like bodies, nuclear pyknosis, cytoplasmic eosinophilia, cytolysis, inflammation and a mild cellular infiltration composed of mononuclear cells and neutrophils. Kidney damage: distal tubular cells and collecting ducts. Glomeruli or proximal tubules. In a few cases, renal failure was reported. Cardiovascular system: postural hypotension and relative bradycardia, arrhythmias are transient and benign. Different degrees of dehydration, uremia, proteinuria, hematuria and oliguria. Respiratory: dry cough, without sore throat. Pharyngeal enanthem. Interstitial or bronchial pneumonia, pulmonary edema and hemorrhage.