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investigation of Covid 19gdjndjsjsbdbdjdnd.pptx
- 1. INVESTIGATION OF AN EPIDEMICWITH REFERENCE TO COVID 19 Presented by – G. Bhavana and G. Sakshi
- 2. Contents ■ Epidemiology ■ Definitionsrelated to epidemiology ■ Epidemiology of Covid 19 ■ Steps to investigate and epidemic ■ Investigation of Covid 19 as an epidemic
- 3. ■ Epidemiology Epidemiology isdefined as “The study of the occurrence and distribution of health related events, states and processes in specified populations, including the study of the determinants influencing such processes, and the application of this knowledge to control relevant health problems.”
- 4. Definitions related toepidemiology ■ Epidemic epi= upon and demos= people “the occurrence in a community or region of cases of an illness, specific health related events clearly in excess of normal expectancy ”
- 5. ■ Endemic En=in anddemos= people “Endemic refers to the constant presence of a disease or infectious agent within a given geographic area or population group, without importation from outside; may also refer to usual or expected frequency of the disease within such area or population group.”
- 6. ■ Pandemic “Pandemic isan epidemic occurring over a very wide area, crossing international boundaries, and usually affecting al large number of people”
- 7. EPIDEMIOLOGY OF COVID19 COVID 19 is an acute respiratory illness caused by the ‑ SARS CoV 2 virus, a novel betacoronavirus first identified in ‑ ‑ Wuhan, China in December 2019. ■ It quickly escalated into a global pandemic, declared by WHO on 11 March 2020.
- 8. ■ Incubation Period ■Average: 4–5 days ■ Range: 2–14 days Transmission possible before onset of symptoms (pre symptomatic spread). ‑ ■ Transmission occurs mainly via respiratory droplets, aerosols, and contact with contaminated surfaces. It has affected all age groups, with severity increasing with age and comorbidities.
- 10. ■ Case Definition ■(WHO/CDC guidelines — summarized) – Suspected case: Acute onset of fever and cough, OR at least 3 symptoms (fever, cough, fatigue, headache, myalgia, sore throat, loss of smell/taste, diarrhea), AND history of contact/travel to affected area within 14 days. – Probable case: Suspected case with inconclusive lab result OR strong epidemiological link to confirmed case. – Confirmed case: Laboratory confirmation of SARS CoV 2 infection by RT PCR or approved ‑ ‑ ‑ antigen/NAAT test, regardless of symptoms.
- 15. Treatment – Mild cases:Symptomatic (paracetamol, hydration, rest) – Moderate/severe: – – Oxygen therapy to maintain SpO ≥ 94% ₂ – Corticosteroids (e.g., dexamethasone) for patients requiring oxygen – Antivirals (e.g., remdesivir in selected hospitalized patients) – Anticoagulation in hospitalized patients to prevent thromboembolism – Critical care: Mechanical ventilation, vasopressors, organ support as required
- 16. Investigation of anepidemic ■ Objectives 1. To define the magnitude of the epidemic outbreak or involvement in terms of time, place and person . 2. To determine the particular conditions and factors responsible for the occurrence of the epidemic . 3. To identify the cause, source of infection and modes of transmission to determine measures necessary to control the epidemic. 4. To make recommendations to prevent recurrence.
- 17. Steps to investigateepidemic
- 18. Investigation of Covid19 as an epidemic 1. Prepare for Field Work Objective: Be ready with resources, team, permissions, and protocols. COVID 19 example: ‑ In December 2019, Chinese health authorities assembled teams of epidemiologists, clinicians, lab scientists. PPE, viral transport media, swabs, and case reporting formats prepared. ‑ Biosafety protocols readied for handling a suspected novel pathogen.
- 19. 2. Establish theExistence of an Epidemic Objective: Determine if there is an actual increase in cases compared to baseline. COVID 19 example: ‑ Wuhan hospitals reported cluster of pneumonia of unknown cause in late Dec 2019. Number of atypical pneumonia cases exceeded expected baseline for that season. This indicated a possible outbreak.
- 20. 3. Verify theDiagnosis Objective: Confirm that the health events are real and correctly diagnosed. COVID 19 example: ‑ Clinicians documented fever, cough, dyspnea, abnormal chest CT (bilateral ground glass opacities). ‑ Respiratory samples analyzed → new betacoronavirus detected by RT PCR and genome sequencing. ‑ Ruled out influenza, SARS CoV, MERS CoV, bacterial pneumonias. ‑ ‑
- 21. 4. Define andIdentify Cases Objective: Develop a case definition and identify all cases. COVID 19 example: ‑ Early case definition: “Pneumonia of unknown cause + travel to Huanan seafood market.” Later expanded to: Fever + respiratory symptoms ± epidemiological link to a confirmed case. Used line listing to record demographic data, symptoms, exposure history. ‑
- 22. 5. Describe andOrient the Data in Terms of Time, Place, and Person (Descriptive Epidemiology) Time: Epidemic curve showed sharp rise in Jan 2020, then global spread. Place: Initial clustering in Wuhan; spread to other provinces, then other countries. Person: All ages affected; severe cases mostly elderly or with comorbidities.
- 25. 6. Develop Hypotheses Objective:Propose possible source, mode of transmission, risk factors. COVID 19 example: ‑ Hypothesis: Exposure to live animals at wet market → zoonotic spillover. Possible human to human transmission via respiratory droplets ‑ ‑ suspected. Severity increased in older adults, immunocompromised.
- 26. 7. Evaluate Hypotheses Objective:Test hypotheses using analytical epidemiology. COVID 19 example: ‑ Case–control studies showed contact with a confirmed patient increased odds of illness. Household transmission documented. Lab studies confirmed SARS CoV 2 survives on surfaces, spreads via ‑ ‑ droplets/aerosols.
- 27. 8. Refine Hypothesesand Carry Out Additional Studies Objective: Modify understanding based on findings. COVID 19 example: ‑ Confirmed human to human transmission including asymptomatic carriers. ‑ ‑ Identified superspreader events (e.g., choir practices, conferences). Expanded surveillance to all symptomatic respiratory illness, not just those linked to wet markets.
- 28. 9. Implement Controland Prevention Measures Objective: Act immediately to contain spread (don’t wait until investigation ends). COVID 19 example: ‑ Travel restrictions and lockdowns in Wuhan. Quarantine of contacts, isolation of cases. Universal masking, hand hygiene, social distancing. Development of vaccines under emergency use authorization.
- 29. 10. Communicate Findings Objective:Share results with health authorities, public, and scientific community. COVID 19 example: ‑ WHO notified on 31 Dec 2019. Genome sequence published Jan 2020 for global research. Regular situation reports, press briefings, research publications.
- 30. SWOT Analysis ofinvestigation of COVID 19 as an epidemic S - Strengths W - Weaknesses O - Opportunities T - Threats
- 31. STRENGTHS Early activation of Integrateddisease surveillance program Active involvement of ICMR in testing and research Rapid development of indigenous RT- PCR kits Creation of Aarogya Setu app for contact tracing Nationwide lockdown bought time to scale testing Deployment of central surveillance teams to outbreak areas Strong research institutions (e.g., NIV Pune) for genome sequencing
- 32. Weaknesses Shortage of trained epidemiologists and health workers Under-reporting andlack of early widespread testing Delay in ramping up genomic surveillance of variants Inconsistent data reporting across states Rural health systems were overburdened or underprepared Limited private lab involvement in initial phase Digital divide hampered contact tracing in low-tech regions
- 33. Opportunities Strengthening digital health systems like CoWINand eSanjeevani Investment in One Health to monitor zoonotic sources Improving inter- state coordination and data sharing Promoting community- based surveillance systems Capacity building in genomics, AI- based modelling, and field epidemiology Boosting public- private partnerships in epidemiology
- 34. Threats Spread of misinformation and vaccine hesitancy Riskof new variants compromising control efforts Stigma and fear affecting contact tracing efforts High population density accelerated transmission Inter-state migration contributed to spread Disruption of routine health programs (e.g., TB, immunization) Political interference delaying accurate outbreak communication
- 35.