Date: Fri 5 Jul 2019
Source: GIDEON (Global Infectious Disease Epidemiology Network) [edited]
In 2019, a small outbreak of Bolivian haemorrhagic fever was reported at a hospital in La Paz [department], Bolivia. The following background data on Bolivian haemorrhagic fever are abstracted from Gideon www.GideonOnline.com
and the Gideon e-book series.[1,2] Primary references are available from the author.
Bolivian haemorrhagic fever (BHF) is caused by Machupo virus (Arenaviridae, Tacaribe complex, _Mammarenavirus_). The disease was initially described in 1959 as a sporadic hemorrhagic illness in rural areas of Beni department, eastern Bolivia, and the virus itself was 1st identified in 1963. BHF is most common during April to July in the upper savanna region of Beni. Principal exposure occurs through rodents ([the large vesper mouse] _Calomys callosus_), which enter homes in endemic areas.
BHF is one of several human _Arenavirus_ diseases reported in the Americas: Argentine haemorrhagic fever (Junin virus), Brazilian haemorrhagic fever (Sabia virus), lymphocytic choriomeningitis, Venezuelan haemorrhagic fever (Guanarito virus) and Whitewater Arroyo virus infection. (At least 2 related diseases are reported in Africa: Lassa fever and Lujo virus infection.)
Infection of _C. callosus_ results in asymptomatic viral shedding in saliva, urine, and feces; 50% of experimentally infected _C. callosus_ are chronically viremic and shed virus in their bodily excretions or secretions. _C. callosus_ acquires the virus after birth, and start shedding it through their urine and saliva while suckling. When mice acquire the virus as adults, they may develop immunity and no longer shed the virus.
Although the infectious dose of Machupo virus in humans is unknown, exposed persons may become infected by inhaling virus in aerosolized secretions or excretions of infected rodents, ingestion of food contaminated with rodent excreta, or by direct contact of excreta with abraded skin or oropharyngeal mucous membranes. Nosocomial and human-to-human spread have been documented. Hospital contact with a patient has resulted in person-to-person spread of Machupo virus to nursing and pathology laboratory staff.
In 1994, fatal secondary infection of 6 family members in Magdalena, Bolivia from a single naturally acquired infection further suggested the potential for person-to-person transmission.
During December 2003 to January 2004, a small focus of haemorrhagic fever was reported in the area of Cochabamba. A 2nd _Arenavirus_, Chapare virus, was recovered from one patient with fatal infection.
Early clinical manifestations consist of nonspecific signs and symptoms, including fever, headache, fatigue, myalgia, and arthralgia. Within 7 days, patients may develop hemorrhagic signs, including bleeding from the oral and nasal mucosa and from the bronchopulmonary, gastrointestinal, and genitourinary tracts. Case fatality rates range from 5% to 30%.
Ribavirin has been used successfully in several cases of BHF. The recommended adult regimen is 2.0 g intravenously (IV), followed by 1.0 g IV every 6 hours for 4 days, and then 0.5 g every 8 hours for 6 days.
Note that the etiologic agent and clinical features of BHF are similar to those of Argentine hemorrhagic fever (AHF). Neurological signs are more common in AHF, while hemorrhagic diatheses are more common in BHF. A vaccine available for AHF could theoretically be effective against BHF as well.
1. Berger S. American hemorrhagic fevers: global status, 2019. Gideon e-books.
2. Berger S. Infectious diseases of Bolivia, 2019. 342 pages, 87 graphs, 495 references.
Tel Aviv Medical Center, Israel
[ProMED-mail thanks Dr. Berger for the overview of Bolivian haemorrhagic fever presented above. As noted in the previous comment, and above, Bolivian haemorrhagic fever, caused by Machupo virus, occurs sporadically in lowland Bolivia, especially in Beni department. There was a case there in 2013, and in 2012 ProMED-mail reported that 13 people had been infected with Machupo virus and 7 had died as a consequence of the disease. In Beni department at that time, 5 municipalities, including Magdalena, were reported to have had large populations of _Calomys callosus_ mice, the reservoir host of Machupo virus, which can persistently infect the mice. It is not surprising to find cases in lowland areas of La Paz department again, where the current cases are occurring. The drylands vesper mouse, _C. musculinus_ mentioned in the previous post, although present in southern Bolivia, is unlikely to be the reservoir rodent involved in the current cases. _C. callosus_ mice are the recognized reservoir hosts of Machupo virus. Health officials can provide information about rodent control and assist in implementing it to reduce the risk of exposure to Machupo virus, but effective long-term implementation of rodent control ultimately rests with local residents.
An image of _C. callosus_, the large vesper mouse and reservoir host of Machupo virus, can be seen at