July 5th 2019
In 2019, a small outbreak of Bolivian hemorrhagic fever was reported at a hospital in La Paz, Bolivia. The following background data on Bolivian hemorrhagic fever are abstracted from Gideon www.GideonOnline.com and the Gideon e-book series. [1,2] Primary references are available from the author.
Bolivian hemorrhagic 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 first identified in 1963. BHF is most common during April to July in the upper savanna region of Beni. Principal exposure occurs through rodents (Calomys callosus) which enter homes in endemic areas.
BHF is one of several human Arenaviruses diseases reported in the Americas: Argentine hemorrhagic fever (Junin virus), Brazilian hemorrhagic fever (Sabia virus), Lymphocytic choriomeningitis, Venezuelan hemorrhagic fever (Guanarito virus) and Whitewater Arroyo virus infection. (At least two 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 six 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 hemorrhagic fever was reported in the area of Cochabamba. A second 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 seven 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 IV, followed by 1.0 g IV Q6h X 4 days, and then 0.5 g Q8h X 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.
- Berger S. American Hemorrhagic Fevers: Global Status, 2019. Gideon e-books, https://www.gideononline.com/ebooks/disease/american-hemorrhagic-fevers-global-status/
- Berger S. Infectious Diseases of Bolivia, 2019. 342 pages, 87 graphs, 495 references. https://www.gideononline.com/ebooks/country/infectious-diseases-of-bolivia/
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