* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Steps in retrospective epidemiological analysis (REA)
Survey
Document related concepts
Race and health wikipedia , lookup
International Epidemiological Association wikipedia , lookup
Cross-species transmission wikipedia , lookup
Nutrition transition wikipedia , lookup
Group development wikipedia , lookup
Eradication of infectious diseases wikipedia , lookup
Focal infection theory wikipedia , lookup
Forensic epidemiology wikipedia , lookup
Viral phylodynamics wikipedia , lookup
Diseases of poverty wikipedia , lookup
Public health genomics wikipedia , lookup
Epidemiology wikipedia , lookup
Hygiene hypothesis wikipedia , lookup
Infection control wikipedia , lookup
Transcript
Epidemiologic method of investigation Purpose of epidemiology analysis is a study of character, level and dynamics of epidemic process, what is going in a certain territory (settlement, district, region, edge, republic) in the certain span of time (month, quarter, half-year, year, a few years ) Conducting an epidemiological analysis, an epidemiologist sets before itself the followings problems: 1) To expose conformities to the law of epidemic process and his feature at certain infectious diseases in concrete terms; 2) It is correct to define these conformities to the law, unseal their reasons; 3) It study efficiency conducted in the previous year (or years) of and prophylactic measures; 4) To work out a plan of measures, directed on a decline or liquidation of separate infectious diseases, taking into account the features of epidemic process of one or another disease in the concrete terms of the proper area. Materials, necessary for an epidemiology analysis. For an epidemiology analysis the followings materials are needed: 1) description of district, cities, regions on the whole; state of dwelling fund, sewage system and cleaning of territory; presence of different objects, factories, factories, artels, food enterprises, markets, stations etc 2) demographic information for a few years about number and age composition of population, birth-rate, death rate, migration; 3) information about the social and professional structure of population; 4) Number and sanitary state of schools of nurseries, managers and scope by them to child's population; 5) sanitary state of schools, their number and quantity of schoolboys; 6) state of medical service: and) material well-being by doctors and middle medical personnel; 7) information of individual registration of contagious diseases, cards of urgent notification and epidemiology inspection (forms 58 and 171); 8) magazines of registration of infectious diseases 9) forms 85-87 and sanitary epidemiological centre and form; 10) information about a death rate and lethality; 11) information of laboratory researches of material from sick and healthy persons, inspected on the testimonies of epidemiology or according to plan; 12) at the analysis of morbidity zoonological information (quantity and morbidity of rodents, morbidity of wild and home animals by hydrophobia, brucellosis in the whole region , districts and on the inhabited areas 13) at the analysis of morbidity bloody and intestinal infections there is entomological information (quantity of mosquitoes, flies, their infection). Except for the indicated materials needed: 1) reviews of epidemiological and statistical forms of account of infectious morbidity for a previous year. 2) plan of antiepidemiological work for current period. An epidemiological analysis consists of a few sections. It begins from the detailed description of natural and economic features of territory. Geographical position, climatic terms, fauna, flora, soil, reservoirs of settlement, industrial objects, cultural welfare and demographic data are cited, is described in this part. Dynamics of morbidity on years. It is necessary to analyse morbidity for a few years, because here direction of epidemic process comes to light more exactly. For the analysis of infectious morbidity in years it is necessary to use intensive indexes. Studying the level of epidemic process in a dynamics of years, it is necessary to make an effort to find out reasons of its increase or decline for studied period. Study of distributing of infectious diseases on territory. To select the most staggered areas of city, settlements,burrows etc and to analyse character of morbidity in them. It is necessary to select settlements (districts) with more high and more low morbidity, explaining reasons of its different level. Analysis of monthly morbidity. At the analysis of morbidity a large value has a study of reasons of advancing morbidity in the certain months of year (seasonality). It is known that seasonality of infections can depend on climatic terms (tick encephalitis, malaria, fever of dengue when the value of reservoir of virus and carry of infection rises in distribution of diseases, and from production and economic activity of man (rabbit-fever, brucellosis). The degree of contagiousity can influence one or another infection and change of intercourse of people different periods of year (scarletfever, measles and other). At the row of communicable diseases seasonality can change depending on the terms of life of people and equipping with modern amenities of the inhabited places. Seasonality of infections can be studied on the basis of absolute numbers of morbidity on the months of year (information of forms 85-87 and cards of epidemiology inspection of one or another infection). Carefully analyzing these materials, it is possible to exclude from the seasonal spread of diseases, related to the flashes or infection as a result of the use of the infected food product or water, and also cases diseases, related to the infection in other settlements. Analysis of age morbidity. Analysing morbidity, an epidemiologist must define how the persons of different ages are often ill. The study of this question allows correctly to organize a fight on the decline of morbidity among the separate groups of ages from intensity of their defeat. We will suppose, analysing morbidity diphtheria, it is set that children are most often ill from this infection in age 8—9 years. Morbidity on the groups of ages is studied usually in indexes on 10000 (or on 1000) population of the proper age. The absolute numbers of morbidity are not recommended for such analysis, similarly as extensive indexes. The analysis of age morbidity in extensive indexes allows to judge only about average of separate age group in annual morbidity on a settlement on the whole, but he can not show frequency of diseases on the different groups of ages. Analysis of morbidity on the professionally-domestic groups of population. The studying of morbidity on professionally-domestic groups allows an epidemiologist to expose most staggered one or another infection of group of population and at planning and conducting of prophylactic and antiepidemiological measures for the decline of morbidity to pay the special attention to work among the most staggered contingents. At the analysis of distributing of morbidity different infections on the professionally-domestic groups of epidemiologist can interest the different groups of population. So, analyzing morbidity brucellosis, it is necessary to find out, what groups of rural or urban population are most staggered this infection (milkmaids, persons who tends cattle, shepherds, workers of creameries, meat-packing plants ). Analysis of sources and ways of passing to the infection. An exposure of sources is infections which resulted in appearance of new case of disease, and also determination of ways of transmission, instrumental in distribution of the contagious beginning, is an important section in work of epidemiologist. Study of efficiency of measures in regard to the source of infection (exposure, timeliness of diagnostics and quality of hospitalization). The timely conducting of antiepidemiological measures in an infectious place (early exposure, timely diagnostics and hospitalization). Studying of efficiency of measures in the focus of infectious disease. After an exposure and hospitalization of infectious patient at the row of diseases final disinfection is conducted, that must result in liquidation of possibility of distribution of the contagious beginning through the articles of everyday life (at intestinal infections, infections of outward covers, tuberculosis). Estimation of efficiency of bacterial profile. At the row of infectious diseases (diphtheria, poliomyelitis) the most effective mean of fight is vaccine prophylaxis. To judge about efficiency of this morbidity among correctly instiled, noninoculated and inoculated wrong. For the example of such analysis it is suggested to study efficiency tips at diphtheria. SCHEME OF RELATIONSHIP BETWEEN EPIDEMIOLOGY AND RELATED DISCIPLINES Microbiology, Virology, Parasitology, Clinic of infectious diseases, Epizootiology, Noninfectious clinical disciplines, Occupational pathology, Pathological anatomy Health statistics, Hygiene, Health organization EPIDEMIOLOGY Evolutionary theory, Ecology, General and molecular biology, Genetics, Medical and Biological Chemisty, Immunology, Geography, Anthropology History, Economics, Social Hygiene, Archeology Comprehensive study of epidemiological methods Descriptive-histological and comparative-histological (can reveal patterns of evolution of disease, predict their distribution in the future) Ecological method (reservoir pathogen carriers and other natural structure of cells, ranges) The method of statistical analysis (quantitative study level, dynamics, focus of disease, seasonal patterns and other diseases) Molecular biological method (mechanism and causes of variability of influenza virus toxigenicity corynebacterium, microbial resistance to drugs etc) Geographical and mapping method (addiction epidemics of natural factors: natural focus, detecting transmission etc) Socio-economic and socio-hygienic methods (economic cost of morbidity, cost-effectiveness of preventive measures, the importance of sociohygienic conditions etc) Epidemiological survey (clarification in place of the casual relationships that drive the epidemic process) Experimental and epidemiological method (biology blood-sucking vectors, the efficiency of insecticide disinfection, stoked method, etc) Laboratory and epidemiological methods (microbiological, serological studies to identify carriers, patients in cell efficiency of immunization, disinfection, detecting contaminated food, water etc) Sections of Epidemiology FIELD What (instances) Where (place), With whom (person), When it happened (time) EXPOSITORY •Who (person) •Where (place) •When it happened (time) ENTRY EPIDEMIO LOGY ANALYTICAL How Why, Evidencebased medicine Sections of Epidemiology Animals Wild Domestic Synanthropic Source Man Carriers Acute form Sick Chronic form MECHANISM OF TRANSMISSION Convalescents Typical form Atypical form SUSCEP TIBLE ORGAN ISM Scheme of infections transmission: I – Source of infection, II – mechanism of transmission, III – susceptible organism; 1 – discharging of agent from the source, 2 – staying in environment, 3 – penetration to healthy organism. Structure of parasitic system in anthroponosis Biological agents Structure of parasitic system in zoonosis Structure of parasitic system in sapronosis Morbidity (Absolute data) ARVI and influenza in Ternopil Region and Ternopil city (21.108.11.09) 5000 4000 3000 2000 1000 10 /2 1/2 00 10 9 /2 3/2 00 10 9 /2 5/2 00 10 9 /2 7/2 00 10 9 /2 9/2 00 10 9 /3 1/2 11 009 /2 /20 09 11 /4 /20 09 11 /6 /20 09 11 /8 /20 09 0 Region City Morbidity of ARVI and influenza In Ternopil weekly(2005-2009), for 10000 population 400 350 300 250 200 150 100 50 2005 2006 2007 2008 2009 51 49 47 45 43 41 39 37 35 33 31 29 27 25 23 21 19 17 15 13 11 9 7 5 3 1 0 City, children City, adults 11/9/2009 11/8/2009 11/7/2009 11/6/2009 11/5/2009 11/4/2009 11/3/2009 11/2/2009 11/1/2009 10/31/2009 10/30/2009 140 120 100 80 60 40 20 0 10/29/2009 Morbidity of ARVI and influenza among children and adults in Ternopil region and City (29.109.11.09), Per 10000 population Etiological structure of ARVI and Influenza 2009 (in epidemic situation) Influenza B Parainfluenza RS Adenovirus грип А influenza B Parainfluenza RS Adenovirus 2008 OBJECTIVE RETROSPECTIVE EPIDEMIOLOGICAL ANALYSIS 1 2 Estimated epidemical situation based on: Determining patterns of the epidemic process Studying the structure of infectious diseases Social meaning Character of changes in time Character of changes in territory Economical meaning 6 7 Predicting infectious morbidity situation for the next year Studying characteristics of the epidemic, the most topical infections and their causes in specific contexts Trends Detection of infectious diseases which are most common Epidemical meaning 3 Developing rational and scientifically sound approach to planning preventive and antiepidemic measures in the specific area 4 Identifying natural and social conditions and precursors complications of epidemical situation in a particular area 5 Evaluating the effectiveness of prophylactic and preventive measures undertaken in the previous period Steps of retrospective epidemiological analysis І step Assembly of program of investigation Definition of objectives REA Identification of major Directions REA ІІ Step Collection and preprocessing informatio Demographic data Sanitary-hygienic characteristic of district Natural, social and working conditions of populat Steps in retrospective epidemiological analysis (REA) I step 1 Composing software survey Визначення завдань Definition of objectives (REA) РЕА II step 2 Collecting and preprocessing information about: Infectious morbidity step 3 Studying of information about infectious morbidity Analysis of level and structure of infectious morbidity Analysis of long-term dynamics of morbidity trends Demographic data Identification of major areas of REA III Sanitary-hygienic characteristic of district periodicity Average analysis Annual analysis Level of annual morbidity Natural, social and working conditions of population Terms of seasonal increasing Duration of seasonal increasing Analysis of morbidity according to risk factors IV Step 4 Copmosition of retrospective epidemical diagnosis and revealing of actual problems of infectious morbidity to certain territories Age characteristic Professional characteristic Sex characteristic Analysis of morbidity according to territory Seasonal character of Leptospirosis in Ternopil Region (1981-1999 ) Fecal-oral mechanism Air-borne mechanism Transmissive mechanism Contact (wound) mechanism Epidemiological methods For achieving the above objectives various methods are used by epidemiologists. They have evolved from 19th century: 1. Observational 2. Experimental Observational – as the name implies involves only making observations on what has happened to persons and communities and make inferences from these observations. It may be further classified into descriptive and analytical. Descriptive studies observe health phenomena in terms of time / place / person. - Cross-sectional made on populations or communities at one point of time. They give information on the community just as a cross section of a specimen gives informationat that particular level of sectioning. - Longitudinal surveys conducted over long periods in the same population. They give information over different time points. Useful in calculating incidence rates and drawing time trends in health and disease. Analytical designs Based on specific hypothesis generated from cross sectional or longitudinal studies. Used to gather data and the data is analysed to test the specific hypotesis. May be called retrospective studies when both the exposure and outcome has occurred before the study commences. They are prospective when both exposure and outcomes are yet to occur. Experimental design Are methods where suspected causal situation is induced in selected and control populations and their effects are observed to prove or disprove a hypothesis. The major modalities of experimental designs in vogue currently may be classified as follows: - Randomised controlled clinical trial; - Field trials; - Community trials. Inspection – revealing of the source Examination – studying of morbidity Analysis of morbidity Experiment – microbiological and serological examination, physical and chemical studies, experiment on humans and animals Thanks For Your Attention!