Argentine hemorrhagic fever
Encyclopedia
Argentine hemorrhagic fever (AHF) 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
(an arenavirus
, closely related to the Machupo virus, causative agent
of Bolivian hemorrhagic fever
). Its vector is a species of rodent
, the corn mouse.
, caused by chemical pollution. It was associated with fields containing stubble after the harvest, giving it another of its names.
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.
If untreated, the mortality of AHF reaches 15–30%. The specific treatment includes plasma
of recovered patients, which, if started early, is extremely effective and reduces mortality to 1%. Ribavirin
has also shown some promise in treating arenaviral diseases.
The disease was first detected in the 1950s in the Junín Partido
in Buenos Aires, after which its agent, the Junín virus, was named upon its identification in 1958. In the early years, about 1,000 cases per year were recorded, with a high mortality rate (more than 30%). The initial introduction of treatment serums in the 1970s reduced this lethality.
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
.
also conducted search and developing programs on the potential of the hemorragic fever as biological weapon.
Zoonosis
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...
occurring in Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
. It is caused by the 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...
(an arenavirus
Arenavirus
Arenavirus is a genus of virus that infects rodents and occasionally humans. At least eight Arenaviruses are known to cause human disease. The diseases derived from Arenaviruses range in severity. Aseptic meningitis, a severe human disease that causes inflammation covering the brain and spinal...
, closely related to the Machupo virus, causative agent
Etiology
Etiology is the study of causation, or origination. The word is derived from the Greek , aitiologia, "giving a reason for" ....
of Bolivian hemorrhagic fever
Bolivian hemorrhagic fever
Bolivian hemorrhagic fever , also known as black typhus or Ordog Fever, is a hemorrhagic fever and zoonotic infectious disease originating in Bolivia after infection by Machupo virus....
). Its vector is a species of rodent
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....
, the corn mouse.
Epidemiology
The disease was first reported in a small place called O'Higgins (Spanish Wikipedia) in Buenos Aires province, Argentina in 1958, giving it one of the names by which it is known. Various theories about its nature were proposed: it was Weil's disease, leptospirosisLeptospirosis
Leptospirosis is caused by infection with bacteria of the genus Leptospira, and affects humans as well as other mammals, birds, amphibians, and reptiles.The...
, caused by chemical pollution. It was associated with fields containing stubble after the harvest, giving it another of its names.
The endemic area of AHF covers approximately 150,000 km², compromising the provinces
Provinces of Argentina
Argentina is subdivided into twenty-three provinces and one autonomous city...
of Buenos Aires
Buenos Aires Province
The Province of Buenos Aires is the largest and most populous province of Argentina. It takes the name from the city of Buenos Aires, which used to be the provincial capital until it was federalized in 1880...
, Córdoba
Córdoba Province (Argentina)
Córdoba is a province of Argentina, located in the center of the country. Neighboring provinces are : Santiago del Estero, Santa Fe, Buenos Aires, La Pampa, San Luis, La Rioja and Catamarca...
, Santa Fe
Santa Fe Province
The Invincible Province of Santa Fe, in Spanish Provincia Invencible de Santa Fe , is a province of Argentina, located in the center-east of the country. Neighboring provinces are from the north clockwise Chaco , Corrientes, Entre Ríos, Buenos Aires, Córdoba, and Santiago del Estero...
and La Pampa
La Pampa Province
La Pampa is a sparsely populated province of Argentina, located in the Pampas in the center of the country. Neighboring provinces are from the north clockwise San Luis, Córdoba, Buenos Aires, Río Negro, Neuquén and Mendoza.-History:...
, with an estimated risk population of 5 million.
The vector, a small rodent known locally as ratón maicero
Drylands Vesper Mouse
The Drylands Vesper Mouse is a species of rodent in the family Cricetidae.It is found in Argentina and Paraguay.-References:* Baillie, J. 1996. . Downloaded on 9 July 2007....
("maize mouse"; Calomys musculinus), suffers from chronic asymptomatic
Symptom
A symptom is a departure from normal function or feeling which is noticed by a patient, indicating the presence of disease or abnormality...
infection, and spreads the virus through its saliva
Saliva
Saliva , referred to in various contexts as spit, spittle, drivel, drool, or slobber, is the watery substance produced in the mouths of humans and most other animals. Saliva is a component of oral fluid. In mammals, saliva is produced in and secreted from the three pairs of major salivary glands,...
and urine
Urine
Urine is a typically sterile liquid by-product of the body that is secreted by the kidneys through a process called urination and excreted through the urethra. Cellular metabolism generates numerous by-products, many rich in nitrogen, that require elimination from the bloodstream...
. 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.
Clinical aspects
AHF is a grave acute disease which may progress to recovery or death in 1 to 2 weeks. The incubation time of the disease is between 10 and 12 days, after which the first symptoms appear: fever, headaches, weakness, loss of appetite and will. These intensify less than a week later, forcing the infected to lie down, and producing stronger symptoms such as vascular, renal, hematological and neurological alterations. This stage lasts about 3 weeks.If untreated, the mortality of AHF reaches 15–30%. The specific treatment includes plasma
Blood plasma
Blood plasma is the straw-colored liquid component of blood in which the blood cells in whole blood are normally suspended. It makes up about 55% of the total blood volume. It is the intravascular fluid part of extracellular fluid...
of recovered patients, which, if started early, is extremely effective and reduces mortality to 1%. Ribavirin
Ribavirin
Ribavirin is an anti-viral drug indicated for severe RSV infection , hepatitis C infection and other viral infections. Ribavirin is a prodrug, which when metabolised resembles purine RNA nucleotides...
has also shown some promise in treating arenaviral diseases.
The disease was first detected in the 1950s in the Junín Partido
Junín Partido
Junín is a municipality in the . Its capital is the city of Junín.-Geography:Junín occupies an area of , with a population of 88,664 inhabitants...
in Buenos Aires, after which its agent, the Junín virus, was named upon its identification in 1958. In the early years, about 1,000 cases per year were recorded, with a high mortality rate (more than 30%). The initial introduction of treatment serums in the 1970s reduced this lethality.
Vaccine
The Candid #1 vaccineVaccine
A vaccine is a biological preparation that improves immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism, and is often made from weakened or killed forms of the microbe or its toxins...
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
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, 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$
Argentine peso
The peso is the currency of Argentina, identified by the symbol $ preceding the amount in the same way as many countries using dollar currencies. It is subdivided into 100 centavos. Its ISO 4217 code is ARS...
8 each (about US$
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....
2.6 or €
Euro
The euro is the official currency of the eurozone: 17 of the 27 member states of the European Union. It is also the currency used by the Institutions of the European Union. The eurozone consists of Austria, Belgium, Cyprus, Estonia, Finland, France, Germany, Greece, Ireland, Italy, Luxembourg,...
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
Bolivian hemorrhagic fever
Bolivian hemorrhagic fever , also known as black typhus or Ordog Fever, is a hemorrhagic fever and zoonotic infectious disease originating in Bolivia after infection by Machupo virus....
.
Weaponization
Argentine 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. The Soviet UnionSoviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....
also conducted search and developing programs on the potential of the hemorragic fever as biological weapon.