RESUMEN
Hantaviruses are rodent-borne agents belonging to the Bunyaviridae family. These viruses, which are found throughout Europe, Asia and the Americas, are maintained by different species of rodents, in which they produce chronic, inapparent infections. Humans become infected through contact with urine, saliva or faeces from infected rodents, mainly via the aerosol route. In humans, clinical disease occurs in the form of two major syndromes: haemorrhagic fever with renal syndrome (HFRS) or hantavirus pulmonary syndrome (HPS). Haemorrhagic fever with renal syndrome mainly occurs in Europe and Asia and HPS has only ever been reported in the Americas. Person-to-person transmission of hantaviruses, although uncommon, was described during an outbreak of HPS in southern Argentina. Most epidemics of HFRS and HPS occur in areas with large populations of rodents that have a relatively high prevalence of infection.
Asunto(s)
Infecciones por Hantavirus/epidemiología , Síndrome Pulmonar por Hantavirus/epidemiología , Fiebre Hemorrágica con Síndrome Renal/epidemiología , Orthohantavirus/patogenicidad , Roedores/virología , Animales , Reservorios de Enfermedades/veterinaria , Infecciones por Hantavirus/transmisión , Infecciones por Hantavirus/veterinaria , Síndrome Pulmonar por Hantavirus/transmisión , Fiebre Hemorrágica con Síndrome Renal/transmisión , HumanosRESUMEN
Argentine hemorrhagic fever (AHF), caused by the arenavirus Junin, is a major public health problem among agricultural workers in Argentina. A prospective, randomized, double-blind, placebo-controlled, efficacy trial of Candid 1, a live attenuated Junin virus vaccine, was conducted over two consecutive epidemic seasons among 6500 male agricultural workers in the AHF-endemic region. Twenty-three men developed laboratory-confirmed AHF during the study; 22 received placebo and 1 received vaccine (vaccine efficacy 95%; 95% confidence interval [CI], 82%-99%). Three additional subjects in each group developed laboratory-confirmed Junin virus infection associated with mild illnesses that did not fulfill the clinical case definition for AHF, yielding a protective efficacy for prevention of any illness associated with Junin virus infection of 84% (95% CI, 60%-94%). No serious adverse events were attributed to vaccination. Candid 1, the first vaccine for the prevention of illness caused by an arenavirus, is safe and highly efficacious.
Asunto(s)
Arenavirus del Nuevo Mundo/inmunología , Fiebre Hemorrágica Americana/prevención & control , Fiebre Hemorrágica Americana/terapia , Vacunas Atenuadas/uso terapéutico , Vacunas Virales/uso terapéutico , Adolescente , Adulto , Enfermedades de los Trabajadores Agrícolas/prevención & control , Enfermedades de los Trabajadores Agrícolas/terapia , Enfermedades de los Trabajadores Agrícolas/virología , Animales , Anticuerpos Antivirales/análisis , Anticuerpos Antivirales/inmunología , Arenavirus del Nuevo Mundo/crecimiento & desarrollo , Argentina , Células Cultivadas , Chlorocebus aethiops , Método Doble Ciego , Fiebre Hemorrágica Americana/diagnóstico , Humanos , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Estaciones del Año , Vacunas Atenuadas/efectos adversos , Células Vero , Vacunas Virales/efectos adversosRESUMEN
To explore the endogenous interferon levels in patients of Argentine hemorrhagic fever (AHF) with different clinical evolution of the disease, 29 fatal and 33 surviving cases of AHF were analyzed. As previously reported, the titers of endogenous alpha-IFN in patients with AHF are very high, generally between 2,000 and 64,000 IU/ml. Thus far, these are the highest levels of circulating interferon detected in any human viral disease. In this study it was found that during the second week of evolution the titers of interferon were significantly higher in fatal cases than in survivors. Therefore, very high levels of interferon have a prognostic value in AHF.
Asunto(s)
Fiebre Hemorrágica Americana/inmunología , Interferón Tipo I/sangre , Estudios de Seguimiento , Fiebre Hemorrágica Americana/sangre , Fiebre Hemorrágica Americana/mortalidad , Humanos , Interferón Tipo I/biosíntesis , CinéticaRESUMEN
P6 a retrospective study outcome in patients with Argentine haemorrhagic fever was associated with the amount of neutralising antibodies against Junin virus present in the transfused units of immune plasma. Low doses of neutralising antibodies were associated with higher mortality. A prospective study gave comparable results. A dose of no less than 3000 therapeutic units of neutralising antibodies per kg body weight is recommended. It is also suggested that the lack of effectiveness of immune plasma in the treatment of other viral haemorrhagic fevers, such as Lassa fever and Crimean-Congo haemorrhagic fever, may be due to a low dose of the specific neutralising antibodies.
Asunto(s)
Anticuerpos Antivirales/administración & dosificación , Arenaviridae/inmunología , Arenavirus del Nuevo Mundo/inmunología , Fiebre Hemorrágica Americana/terapia , Inmunización Pasiva , Anticuerpos Antivirales/inmunología , Relación Dosis-Respuesta Inmunológica , Fiebre Hemorrágica Americana/mortalidad , Humanos , Pruebas de Neutralización , Estudios Prospectivos , Estudios RetrospectivosRESUMEN
The induction of endogenous interferon (IFN) was studied in 28 cases of Argentine hemorrhagic fever (AHF), a severe systemic disease caused by Junin virus. Serum samples were taken daily during the acute period, both before and after administration of immune plasma. This form of treatment has been found to reduce mortality when given early in the course of AHF. High titers of circulating IFN were present in the serum samples taken before treatment. IFN titers drastically dropped after transfusion of immune plasma. The antiviral activity was stable at pH 2 and was completely neutralized only by antibodies against IFN-alpha. Thus, we concluded that circulating endogenous IFN in patients with AHF can be considered as typical IFN-alpha. Fever, chills, and backache were associated with the higher levels of IFN. An inverse correlation between days of evolution of the disease and IFN activity was also observed.
Asunto(s)
Fiebre Hemorrágica Americana/sangre , Interferón Tipo I/sangre , Dolor de Espalda/etiología , Fiebre/etiología , Fiebre Hemorrágica Americana/terapia , Humanos , Inmunización Pasiva , Tiritona , Viremia/sangreRESUMEN
To determine the prevalence of inapparent infection with Junin virus among the rural population and its relation to the clinical disease, a serological study was carried out in two zones of the endemic area of Argentine hemorrhagic fever (AHF). From the first appearance of AHF in the zones (1963) and the moment of the survey (1977), 14 years had passed. A total of 695 serum samples were obtained, 540 from Córdoba and 155 from Buenos Aires. Of the 695 serum samples, 83 were positive for neutralizing antibodies against Junin virus. Total infection (clinical and inapparent cases) reached 11.6% and 12.03% in the Buenos Aires and Córdoba zones, respectively, showing that the total prevalence of infection in two zones separated by 320 miles, are very much alike. In Córdoba province, the prevalence of clinical infection was 7.59%, while that for inapparent infection was 4.44%. Values for the Province of Buenos Aires were 9.67% and 1.93%, respectively. In addition to a low prevalence of inapparent infections, the results of this survey show that roughly 90% of the population is susceptible to contract the disease; this stresses the need to immunize susceptible individuals in the endemic area.