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South American hemorrhagic fevers
Last reviewed: 04.07.2025
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South American hemorrhagic fevers (Argentine, Bolivian, Venezuelan) are common only in these regions and pose a serious problem for local health authorities. In Argentina, 100 to 200 cases of hemorrhagic fever are diagnosed annually. In recent years, a specific vaccine has been used to prevent Argentine hemorrhagic fever and a fairly high vaccination efficiency has been noted.
The incidence of Bolivian and Venezuelan hemorrhagic fevers is somewhat lower than that of Argentina, with several dozen cases registered annually. In 1990, the Sabia virus was identified, only a few cases of the disease caused by it and called Brazilian hemorrhagic fever have been described, the natural reservoir of the pathogen has not yet been fully studied. Human infection occurs in the same way as with Lassa fever. The epidemiological characteristics of South American hemorrhagic fevers are fundamentally similar to the characteristics of Lassa fever.
[ What causes South American hemorrhagic fevers?
The pathogenesis of South American hemorrhagic fevers is poorly understood. Its main features are very similar to the pathogenetic mechanisms of Lassa fever (the role of MFG in the development of the disease, primary viral damage to monocytes, activation of cytokines, formation of multiple organ damage, impaired vascular permeability due to endothelial damage, development of DIC syndrome, toxic shock, collapse). A dependence of the severity of the infection on the level of interferon-alpha in the blood serum of patients has been established: with its significant increase by 6-12 days of illness, the disease ended in death (at autopsy, significant blood filling was found in the spleen, liver, red bone marrow).
Vascular damage in South American hemorrhagic fevers is less pronounced than in Lassa fever.
In most cases of South American hemorrhagic fevers, secondary bacterial infection occurs with the development of bronchopneumonia.
Symptoms of South American Hemorrhagic Fever
The incubation period ranges from 5 to 19 days (usually 7-12 days); with parenteral transmission of infection, it is reduced to 2-6 days.
The symptoms of South American hemorrhagic fever are very similar.
The onset of the disease is acute: body temperature quickly rises to high numbers, myalgias of various localizations develop, especially in the back muscles, and general weakness. Patients often note symptoms of South American hemorrhagic fever: pain in the eyeballs, photophobia, pain in the epigastrium, constipation. Dizziness often occurs, orthostatic collapses are possible.
When examining patients, hyperemia of the face and neck, conjunctivitis, and enlarged peripheral lymph nodes are noted. Exanthema in the form of petechiae and small vesicles on the skin (usually in the axillary areas) and on the mucous membranes is characteristic. Hemorrhagic manifestations in the form of petechial rash and bleeding (nasal, gastric, etc.) may be early clinical signs in the first days of the disease. Depression or excitation of the central nervous system is observed.
The course of the disease can be aggravated by the development of convulsive syndrome (clonic seizures) and coma, which greatly complicate the prognosis.
All South American hemorrhagic fevers are especially severe in pregnant women. The diseases lead to miscarriages (with high mortality), and the infection can be transmitted to the fetus.
In the blood, pronounced leukopenia, thrombocytopenia, and an increase in hematocrit are often observed; in the urine, proteinuria.
The recovery period can last up to several weeks, asthenovegetative syndrome (hypotension) is observed for a long time. Hair loss on the head is possible.
Mortality is observed in 15-30% of cases, and in Venezuelan hemorrhagic fever - up to 50%.
Diagnosis of South American hemorrhagic fever
South American hemorrhagic fever diagnostics uses ELISA (IgM), PCR diagnostics have been developed. It is possible to isolate the virus from the blood from the first days of the disease.
What tests are needed?
Treatment of South American Hemorrhagic Fever
Pathogenetic treatment of South American hemorrhagic fever is carried out, aimed at correcting metabolic disorders (metabolic acidosis) and restoring the volume of circulating blood, hemostatic drugs are used. The prescription of antibacterial drugs is indicated when a secondary bacterial infection occurs.
The effectiveness of ribavirin in South American hemorrhagic fever has not been established; convalescent plasma is used in treatment.
How is South American hemorrhagic fever prevented?
Measures for all fevers are aimed at limiting populations of certain rodent species; specific prophylaxis for South American hemorrhagic fever has been developed only for Argentine hemorrhagic fever (live vaccine).