Bolivian haemorrhagic fever

Bolivian hemorrhagic fever (BHF) is caused by the Machupo virus. The Machupo virus was identified as the causative agent of BHF in 1964.

The Junin, Machupo, Guanarito and Sabia viruses belong to the New World arena virus family and occur in South America. These arena viruses are the cause of various hemorrhagic fever diseases such as:

• Argentine hemorrhagic fever
• Bolivian hemorrhagic fever
• Venezuelan hemorrhagic fever
• Brazilian haemorrhagic fever

The name arena virus is derived from a characteristic dark granulation (Latin arenosus = sandy) of the viruses in electron microscopic images. These are shown as ribosomes, which are included in the sprouting of the viruses.

The arena viruses consist of a lipid shell and are pleomorphic with an average diameter of 50-300nm. They contain 2 RNA segments, the L- du the S-segment, which contain the information for structural proteins (nucleocapsid protein and glycoproteins) and an enzyme (viral polymerase). In the finished virus, the nucleocapsid is stored protectively around the RNA. The glycoproteins G1 and G2 are anchored in the lipid envelope. They serve for the absorption and release of the L and S segments into the cytoplasm and are thus essential for recognition and penetration into the host cell. The reproduction of the viruses in the cell takes place via a viral polymerase.

The distribution of the virus appears to be limited to part of the department of Beni in eastern Bolivia. Under normal conditions, infections occur only in sparsely populated, rural regions.

The only known reservoir for the machupo virus is the short-tailed rat (Callomys callosus), which occurs mainly on the edge of tropical grasslands and tropical forests in eastern Bolivia, but also in Paraguay and western Brazil. Between 1959 and 1963, several outbreaks of the BHF occurred with over 1,000 infections. In 1963, as a result of a strong increase in these animals, the Bolivian city of San Joaquin was invaded and the virus was transmitted to several hundred people. The epidemic was brought to an end by an effective rodent control programme.

Infections with the South American hemorrhagic fever viruses are mainly treated symptomatically. In many patients, light sedation (sedation) and pain treatment with opiates is recommended. Bleeding should be treated by transfusions of platelets and coagulation factors.

Control of the electrolyte and fluid balance, if necessary controlled balancing.

In individual cases, infusions of immunoplasmas (plasma from convalescent patients) have been therapeutically successful.

A commercial immunoglobulin does not yet exist.

The antiviral drug ribavirin seems to have a positive influence on the outcome of Junin and Machupo virus infections at least.

Animal experiments with the viral static drug favipiravir have been successful (Gowen BB et al. 2017; Furuta Y et al. 2013), so that it can be assumed that this drug is also used in humans (see Favipiravir).

1. Golden JW et al (2017) An attenuated Machupo virus with a disrupted L-segment intergenic region protects Guinea pigs against lethal Guanarito virus infection. Sci Rep 7:4679.
2. Gowen BB et al (2017) Enhanced protection against experimental Junin virus infection through the use of a modified favipiravir loading dose strategy. Antiviral Res 145:131-135.
3. Tani H et al (2018) Arenavirus research and antiviral candidate. Uirusu 68:51-62.
4. Furuta Y et al (2013) Favipiravir (T-705), a novel viral RNA polymerase inhibitor. Antiviral Res 100:446-454.