RESUMEN
The brief retrospective analysis of morbidity, epizootological data and preventive measures with respect to haemorrhagic fever with renal syndrome (HFRS) during the whole period of its registration on the territory of the Republic of Bashkortostan along with the structure of HFRS morbidity during epidemic seasons of 1998 and 1999 is presented. The main causes of decreased HFRS morbidity in 1998, its rise in 1999 as well as prognosis for the year 2000 were detected. The level of HFRS morbidity among the population was found to be directly related to the number of rodents and their infection rate. The basic strategy of epidemic control interventions has been proposed.
Asunto(s)
Fiebre Hemorrágica con Síndrome Renal/prevención & control , Animales , Baskiria/epidemiología , Reservorios de Enfermedades , Fiebre Hemorrágica con Síndrome Renal/epidemiología , Humanos , Estudios Retrospectivos , Roedores/virología , Estaciones del AñoRESUMEN
The outbreak of hemorrhagic fever with renal syndrome (HFRS) in the Republic of Bashkortostan, resulting in 10,057 registered cases of the disease (287 cases per 100,000 of the population), was analyzed. HFRS cases among the population were registered in 52 out of 54 regions of Bashkortostan. 31% of the total number of patients were the inhabitants of rural regions (170 cases per 100,000) and 69% were urban dwellers (295 cases per 100,000), mainly in Ufa (512 cases per 100,000). HFRS morbidity among males was fourfold higher than among females. In 70% of cases persons aged 20-49 years were affected. 5% of the total number of patients were children aged up to 14 years. In 34 cases (0.4%) the severe clinical course of the disease had a fatal outcome. Cases of HFRS were registered from April 1997 till March 1998 with the highest morbidity rate observed during the period of August-December. In most cases (46.8%) both urban and rural dwellers contacted infection during a short-term stay in the forest. As the result of the serological examination of the patients, all HFRS cases were etiologically attributed to hantavirus, serotype Puumala. The main natural reservoir of this virus and the source of human infection in Bashkortostan were bank voles (Clethrionomys glareolus), the domination species among small mammals in this region.
Asunto(s)
Brotes de Enfermedades/estadística & datos numéricos , Fiebre Hemorrágica con Síndrome Renal/epidemiología , Adolescente , Adulto , Distribución por Edad , Animales , Baskiria/epidemiología , Niño , Reservorios de Enfermedades/estadística & datos numéricos , Reservorios de Enfermedades/veterinaria , Vectores de Enfermedades , Femenino , Fiebre Hemorrágica con Síndrome Renal/inmunología , Fiebre Hemorrágica con Síndrome Renal/transmisión , Humanos , Masculino , Persona de Mediana Edad , Roedores , Población Rural/estadística & datos numéricos , Estaciones del Año , Estudios Seroepidemiológicos , Distribución por Sexo , Población Urbana/estadística & datos numéricosRESUMEN
For the first time the natural immune stratum to hemorrhagic fever with the renal syndrome (HFRS) among the population of all regions of Bashkiria, a large territory with the highest morbidity level in this infection in the USSR, was studied. 9,176 persons over 15 years of age were examined by radioimmune techniques. Analysis of the immune structure of the population revealed that the share of immune males was higher than that of immune females, but the difference was less than the difference between males and females among the registered HFRS patients. Among children immune persons were almost completely absent. The immune stratum increased rather slowly among persons under 40 years, and only from this age the considerable increase of the immune stratum was observed (up to 16.2%). High risk groups included persons of such professions as forestry workers, truck and tractor drivers, oil workers and prospectors, livestock breeders, builders. These data may be used for the formation of groups to be vaccinated against HFRS in foci with different degrees of activity. Before vaccination the correction of groups to be vaccinated in a given region should be carried out, taking into account the immune structure of the population and the specific features of the local landscape and economy.
Asunto(s)
Anticuerpos Antivirales/sangre , Orthohantavirus/inmunología , Factores de Edad , Baskiria/epidemiología , Reservorios de Enfermedades , Fiebre Hemorrágica con Síndrome Renal/epidemiología , Fiebre Hemorrágica con Síndrome Renal/inmunología , Humanos , Ocupaciones/estadística & datos numéricos , Factores de Riesgo , Estudios Seroepidemiológicos , Factores SexualesRESUMEN
The epidemic manifestation of the most active natural foci of HFRS in the USSR on the territory of Bashkiria is described. The authors compare two epidemic seasons of 1975-1976 and 1977-1978. Besides the number of rodents, the rise of morbidity is influenced by their early multiplication and weather conditions. The early appearance of the stable snow cover facilitates a rapid drop in the number of NFRS cases as early as in October, while prolonged autumn with rains, snow, periods of thaw and ice-covered ground leads to a rise in NFRS morbidity occurring in autumn and winter and ending only in March. Weather conditions also influence the epidemiological structure of morbidity.
Asunto(s)
Brotes de Enfermedades , Fiebre Hemorrágica con Síndrome Renal/epidemiología , Estaciones del Año , Tiempo (Meteorología) , Factores de Edad , Animales , Baskiria , Reservorios de Enfermedades , Vectores de Enfermedades , Femenino , Fiebre Hemorrágica con Síndrome Renal/transmisión , Humanos , Masculino , Roedores , Población Rural , Factores SexualesRESUMEN
Natural immunity to the causative agent of hemorrhagic fever with renal syndrome (HFRS) has first been studied using radioimmunoassay (RIA) in the human population of the Bashkir ASSR with the highest incidence of this infection and of five other regions of the RSFSR with lower incidence of HFRS. The antigen was prepared as a suspension of lungs of rodent from natural HFRS foci and contained a high concentration of virus protein. 12,000 sera from the population of 6 areas of the RSFSR were examined. In the Bashkir ASSR antibodies were detected in 13.7 per cent of the subjects examined, this figure varying in different districts from 4.0 to 41.5 per cent. In the other areas the portion of immune subjects varied from 6.7 per cent in Kuybyshev region to 1.6 per cent in Vladimir region. No correlation between the size of the immune portion of the population and average incidence rates for 5 years was observed. In Bashkiriya, immunity was found in 14.9 per cent of men and 11.8 per cent of women. In other regions, the per cent of women with antibodies to HFRS virus was also lower. In the age-group under 40 the percentage of immunity was lower (11.4 per cent) than in older age-groups (17.4 per cent). The portion of immune subjects varied in different occupation groups. In HFRS convalescents the antibody was found to persist in high titre for 20 years (the observation period).