Steps
Step 1
Infectious Disease Selection and Epidemiological Investigation Design
The core task of this step is to select an important infectious disease and design a scientific epidemiological investigation plan. It requires comprehensive consideration of public health importance, data availability, and feasibility.
• Choose an infectious disease from viral hepatitis, tuberculosis, AIDS, influenza, dengue fever, hand-foot-mouth disease, etc.; learn about pathogen characteristics, epidemic overview, and research progress
• Design investigation plan: determine study type (cross-sectional, case-control, cohort study); define study subjects, sample size calculation, sampling method, survey content, and observation indicators; develop investigation timeline
• Design survey tools: design questionnaire (demographic information, exposure history, clinical information, laboratory tests); develop data collection forms and quality control plan; list required equipment and ethical review considerations
Deliverable: Epidemiological investigation design proposal (background, objectives, study design, sample size calculation, survey tools, quality control, ethical considerations) | Quality standard: Scientific and reasonable study design, appropriate method selection, correct sample size calculation, comprehensive quality control measures
Step 2
Data Collection and Three-Dimensional Distribution Description
The core task of this step is to systematically collect disease distribution data and describe disease characteristics by person, time, and place. Three-dimensional distribution description is the foundation of epidemiological research.
• Data collection: collect case data through public health surveillance systems, hospital records, field investigations; include demographic characteristics, onset time, location, clinical manifestations, laboratory test results
• Person distribution analysis: group by age, gender, occupation, ethnicity, marital status; calculate incidence, prevalence, mortality by group; draw population distribution histograms or pie charts
• Time distribution analysis: analyze incidence trends by year, quarter, month, week, day; draw epidemic curves; determine epidemic types (outbreak, seasonal, periodic, secular trend)
• Place distribution analysis: statistics incidence by geographic areas (urban/rural, different provinces/cities, communities); draw dot maps or heatmaps; analyze clustering and transmission range
Deliverable: Three-dimensional distribution description report (person/time/place distribution data tables, statistical charts, epidemic curves, geographic visualization) | Quality standard: Complete and accurate data, comprehensive distribution description, standard and clear charts, in-depth analysis
Step 3
Risk Factor Analysis and Causal Inference
The core task of this step is to analyze disease risk factors and perform causal inference. Use epidemiological analysis methods (case-control, cohort studies) to screen risk factors, assess association strength between exposure and disease.
• Screen risk factors: identify potential risk factors from host factors (age, gender, genetics, immune status), environmental factors (housing conditions, sanitation facilities, air pollution), behavioral factors (diet, smoking/drinking, personal hygiene), social factors (economic level, education, medical resources)
• Association strength analysis: calculate relative risk (RR), odds ratio (OR), attributable risk (AR), population attributable risk percent (PAR%); perform chi-square tests and trend tests; determine statistical association
• Causal inference: apply Hill's criteria for causation (strength of association, consistency, temporality, dose-response relationship, experimental evidence, biological plausibility, etc.) for comprehensive judgment; draw causal chain and web of causation models
Deliverable: Risk factor analysis report (univariate analysis table, multivariate analysis results, association strength indicators, causal inference) | Quality standard: Correct statistical methods, accurate association strength calculation, rigorous causal inference logic
Step 4
Transmission Mechanism Analysis and Prevention Strategy Development
The core task of this step is to analyze disease transmission mechanisms and epidemic patterns, and develop targeted prevention and control strategies and measures. Based on the three basic links of infectious diseases (source, route, susceptible population).
• Transmission mechanism analysis: identify sources of infection (patients, asymptomatic carriers, pathogen carriers, animal reservoirs), transmission routes (respiratory, digestive, contact, vector-borne, blood/maternal-fetal), susceptible population characteristics; analyze basic reproduction number R0 of transmission dynamics
• Epidemic factor analysis: analyze impacts of natural factors (climate, geography, vectors) and social factors (population mobility, sanitation conditions, medical resources, prevention policies); predict epidemic trends
• Develop prevention strategies: propose control measures targeting three links (managing sources, cutting transmission routes, protecting susceptible populations); develop surveillance plans, emergency response plans, health education programs; assess cost-effectiveness
Deliverable: Prevention and control strategy plan (transmission mechanism analysis, epidemic factor analysis, prevention measures list, emergency plan, surveillance plan) | Quality standard: Accurate transmission mechanism analysis, targeted prevention measures, scientific and feasible plan
Step 5
Epidemiological Investigation Report Writing
The core task of this step is to write a complete epidemiological investigation report systematically presenting investigation design, methods, main findings, and prevention recommendations. Epidemiological investigation reports are important basis for public health decision-making.
• Write following epidemiological investigation report standards: abstract, background, objectives, methods, results, analysis and discussion, prevention recommendations, references; minimum 3500 words
• Create high-quality figures and tables: three-dimensional distribution charts, epidemic curves, geographic distribution maps, risk factor analysis tables, forest plots, causal chain diagrams
• In-depth discussion: summarize main findings; discuss study limitations (bias, confounding); compare with other studies; propose further research directions and policy recommendations
Deliverable: Complete epidemiological investigation report (PDF format with all results and analysis), data table appendices, figure collection | Quality standard: Complete structure, reliable data, in-depth analysis, evidence-based conclusions, feasible recommendations, professional format