Bolivian hemorrhagic fever
Bolivian hemorrhagic fever (BHF), also known as black typhus or Ordog Fever, is a hemorrhagic fever and zoonotic
A zoonosis or zoonoseis any infectious disease that can be transmitted from non-human animals to humans or from humans to non-human animals . In a study of 1415 pathogens known to affect humans, 61% were zoonotic...

 infectious disease
Infectious disease
Infectious diseases, also known as communicable diseases, contagious diseases or transmissible diseases comprise clinically evident illness resulting from the infection, presence and growth of pathogenic biological agents in an individual host organism...

 originating in Bolivia
Bolivia officially known as Plurinational State of Bolivia , is a landlocked country in central South America. It is the poorest country in South America...

 after infection by Machupo virus.

BHF was first identified in 1959 by a research group led by Karl Johnson, an ambisense RNA
Ribonucleic acid , or RNA, is one of the three major macromolecules that are essential for all known forms of life....

 virus of the Arenaviridae family. The mortality rate is estimated at 5 to 30 percent. Due to its pathogenicity
Pathogenicity is the ability of a pathogen to produce an infectious disease in an organism.It is often used interchangeably with the term "virulence", although virulence is used more specifically to describe the relative degree of damage done by a pathogen, or the degree of pathogenicity caused by...

, Machupo virus requires Biosafety Level
Biosafety level
A biosafety level is the level of the biocontainment precautions required to isolate dangerous biological agents in an enclosed facility. The levels of containment range from the lowest biosafety level 1 to the highest at level 4 . In the United States, the Centers for Disease Control and...

 Four conditions, the highest level.


The vector is the vesper mouse
Vesper mouse
Calomys is a genus of rodents, also called vesper mice. The genus is widely distributed in South America.Some species are notable as the vectors of Argentinian hemorrhagic fever and Bolivian hemorrhagic fever.-References:...

 Calomys callosus, a rodent
Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....

 indigenous to northern Bolivia. Infected animals are asymptomatic and shed the virus in excreta, thereby infecting humans. Evidence of person-to-person transmission of BHF exists but is believed to be rare.


The infection
An infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...

 has a slow onset with fever
Fever is a common medical sign characterized by an elevation of temperature above the normal range of due to an increase in the body temperature regulatory set-point. This increase in set-point triggers increased muscle tone and shivering.As a person's temperature increases, there is, in...

, malaise
Malaise is a feeling of general discomfort or uneasiness, of being "out of sorts", often the first indication of an infection or other disease. Malaise is often defined in medicinal research as a "general feeling of being unwell"...

, headache
A headache or cephalalgia is pain anywhere in the region of the head or neck. It can be a symptom of a number of different conditions of the head and neck. The brain tissue itself is not sensitive to pain because it lacks pain receptors. Rather, the pain is caused by disturbance of the...

 and muscular pains. Petechia
A petechia is a small red or purple spot on the body, caused by a minor hemorrhage ."Petechiae" refers to one of the three major classes of purpuric skin conditions. Purpuric eruptions are classified by size into three broad categories...

e (blood spots) on the upper body and bleeding from the nose
Human nose
The visible part of the human nose is the protruding part of the face that bears the nostrils. The shape of the nose is determined by the ethmoid bone and the nasal septum, which consists mostly of cartilage and which separates the nostrils...

 and gums are observed when the disease progresses to the hemorrhagic phase, usually within seven days of onset.


Measures to reduce contact between the vesper mouse and humans have effectively limited the number of outbreaks, with no cases identified between 1973 and 1994. Although, there are no cures or immunization for the disease, a vaccine developed for the genetically related Junín virus
Junin virus
-Morphology and genome structure:The Junin virus virion is enveloped with a variable diameter of between 50 and 300 nm. The surface of the particle encompasses a layer of T-shaped glycoprotein extensions, extending up to 10 nm from the envelope, which are important for mediating...

 which causes Argentine hemorrhagic fever
Argentine hemorrhagic fever
Argentine hemorrhagic fever or O'Higgins disease, also known in Argentina as mal de los rastrojos, stubble disease, is a hemorrhagic fever and zoonotic infectious disease occurring in Argentina. It is caused by the Junín virus...

 has shown evidence of cross-reactivity to Machupo virus and may therefore be an effective prophylactic measure for people at high risk of infection.
Post infection (and providing that the person survives the infection), those that have contracted BHF are usually immune to further infection of the disease.


Bolivian hemorrhagic fever was one of three hemorrhagic fevers and one of more than a dozen agents that the United States researched as potential biological weapons before the nation suspended its biological weapons program.
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