Viral hemorrhagic fevers (VHFs) are a group of illnesses caused by four families of viruses. These include the Ebola and Marburg, Lassa fever, and yellow fever viruses. VHFs have common features: they affect many organs, they damage the blood vessels, and they affect the body’s ability to regulate itself. Some VHFs cause mild disease, but some, like Ebola or Marburg, cause severe disease and death.

Arentinan HF disease was first reported in the town of O’Higgins (es) in Buenos Aires province, Argentina in 1958, giving it one of the names by which it is known.^[1] Various theories about its nature were proposed: it was Weil’s disease, leptospirosis, caused by chemical pollution.^[1] It was associated with fields containing stubble after the harvest, giving it another of its names.

The Candid #1 vaccine for AHF was created in 1985 by Argentine virologist Dr. Julio Barrera Oro. The vaccine was manufactured by the Salk Institute in the United States, and became available in Argentina in 1990.

Candid #1 has been applied to adult high-risk population and is 95.5% effective. On 29 August 2006 the Maiztegui Institute obtained certification for the production of the vaccine in Argentina. A vaccination plan is yet to be outlined, but the budget for 2007 allows for 390,000 doses, at AR$8 each (about US$2.6 or €2 at the time). The Institute has the capacity to manufacture, in one year, the 5 million doses required to vaccinate the entire population of the endemic area.

Between 1991 and 2005 more than 240,000 people were vaccinated, achieving a great decrease in the numbers of reported cases (94 suspect and 19 confirmed in 2005).

The Junín vaccine has also shown cross-reactivity with Machupo virus and, as such, has been considered as a potential treatment for Bolivian hemorrhagic fever.

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The endemic area of AHF covers approximately 150,000 km², compromising the provinces of Buenos Aires, Córdoba, Santa Fe and La Pampa, with an estimated risk population of 5 million.

The vector, a small rodent known locally as ratón maicero (“maize mouse”; Calomys musculinus), suffers from chronic asymptomatic infection, and spreads the virus through its saliva and urine. Infection is produced through contact of skin or mucous membranes, or through inhalation of infected particles. It is found mostly in people who reside or work in rural areas; 80% of those infected are males between 15 and 60 years of age.

VHFs are found around the world. Specific diseases are usually limited to areas where the animals that carry them live. For example, Lassa fever is limited to rural areas of West Africa where rats and mice carry the virus.

The risk for travelers is low, but you should avoid visiting areas where there are disease outbreaks. Because there are no effective treatments for some of these viral infections, there is concern about their use in bioterrorism.

Centers for Disease Control and Prevention