Lesson-1 (Epidemiology of Airborne Diseases).pdf

Epidemiology of Airborne Diseases Prof. Dr. Ayşe Nilüfer Özaydın Overview “ Ingenuity, knowledge and organization alter, but Cannot cancel humanity’s vulnerability to invasion by parasitic forms of life , infectious disease which antedated the emergence of...

Epidemiology of Airborne Diseases Prof. Dr. Ayşe Nilüfer Özaydın Overview “ Ingenuity, knowledge and organization alter, but Cannot cancel humanity’s vulnerability to invasion by parasitic forms of life , infectious disease which antedated the emergence of humankind will last as long as humanity itself, and will surely remain, as it has been hitherto, one of the fundamental parameters and determinants of human history. William Hardy Mc Neil-1976, Historian Overview “ Infectious diseases remain a leading cause of morbidity, disability and mortality worldwide. Their control is a constant challenge that faces health workers and public health professionals in both industrilized and developing countries. Only one infectious disease, smallpox, was eradicated and stands as a landmark in the history of the control of infectious diseases. Overview “ Other infectious diseases, like, foiled eradication attempts or control efforts and are re-emerging as increasing threats in many countries. Some infectious diseases, such as tetanus, will always be a threat if control measures are not maintained. Newer infectious disease, like AIDS, Covid19, demonstrate the the truth of McNeill’s statemenet that infectious disease will remain “one of the fundamental parametres and determinants of human history. 5/8/2024 4  Infectious diseases and control “Infection occurs when an infectious agent enters a body and develops and multiplies. infectious agent are organisms capable of producing inapparent infection or clinically manifest disease and include -bacteria, -rickettsia, -chlamydiae, - fungi, - parasites, - viruses and - prions. 5/8/2024 5 Control of Infectious diseases “Control of infectious diseases” refer to the actions and programmes directed i. toward reducing disease incidence (=new infections), ii. reducing disease prevalence (=infections in the community at any given point in time) or iii. completely eradicating the disease…> 5/8/2024 6  Control of Infectious diseases “Control aimed at reducing disease incidence of infectious disease” can be considered as primary prevention of infectious disease. Primary prevention protects heath through individual and community–wide measures such as; - maintaining good nutritional status, - keeping physically fit, - immunizing against infectious diseases, - providing safe water, - ensuring proper disposal of faeces. 5/8/2024 7 Control of Infectious diseases “Control aim of reducing disease prevalence by shortening the duration of infectious disease can be considered as secondary prevention of infection diseases. Secondary prevention corrects departures from good health through individual and community-wide measures including such as -early detection of disease, -prompt antibiotic threatment, -ensuring adequate nutrition. 5/8/2024 8 Control of Infectious diseases “Control aim of reducing or even eliminating long-term impairments of infectious disease can be considered as tertiary prevention of infection diseases. Tertiary prevention reduces or eliminate disabilities, minimizes suffering, and promotes adjustment to permanent disabilities through such actions as -providing orthopedic appliances, -counselling and -vocational training and -prevention of opportunistic infections. 5/8/2024 9  Chain of Infection “ The Chain of Infection is the relationship between i. an infectious agent “ is the first link in the chain of infection” ii. its routes of transmission, iii. a susceptible host. The prevention and control of infectious diseases depend on the interaction of these three factors that may result in the human host clinically manifesting disease. 5/8/2024 10  Chain of Infection Control efforts are often designed to break the routes of transmission, the mechanisms by which infectious agents are spread from reservoirs or sources to human host. A reservoir of an infectious agent is -Any person, -Other living organisms, -Or inanimate material in which the infectious agent normally lives and grows. 5/8/2024 11  Chain of Infection I. Horizontal Transmission; refers to the transmission between individuals, II. Vertical Transmission; refers to the spesific situation of transmission between parent to offspring (e.g. Transplacentally in utero, during passage through the birth canal, through breast milk.) 5/8/2024 12  Airborne Transmission Airborne Transmission; is the dissemination of microbiol aerosols to a suitable portal of entry , usually the respiratuar tract., microbiol aerosols are suspensions of particles in the air consisting partially or wholly of microorganisms. They may remain suspended in the air for long periods of time. Some retaining and others losing infectivity or virulence. Particles in the 1-5µm range are easily drawn into the alveoli of the lungs and may be retained there. Microbial transmission through droplets and other large particles that promptly settle out of the air is considered as “direct” transmission, not airborne transmission. 5/8/2024 13  Airborne Transmission Droplet nuclei; usually the small residues which result from evaporation of fluid from droplets emitted by an infected host. They also may be created purposely by a variety of atomising devices, or accidentally as in microbiology laboratories or in abattoirs, rendering plants or autopsy rooms. They usually remain suspended in the air for long periods. Host; this is the final link in the chain of infection. Infectious agents can be inhaled into the respiratory tract and will be deposited at different levels of the pulmonary tree according to the size of the aerosol, droplet nuclei or dust particles. 5/8/2024 14  Epidemiology of Airborne Diseases On average, an adult inhales about 5 L of air per minute; with exercise, the amount may increase 20-fold or more. With 10,000– 20,000 L of air inhaled daily, agents present even in low concentrations may be toxic. The respiratory system is equipped with a remarkably effective system of defense mechanisms against inhaled particles and gases. Epidemiology of Airborne Diseases Respiratory diseases are major causes of disability and death worldwide, with over 11 million deaths or about 20% of all deaths due to perinatal respiratory conditions, lower respiratory tract infections, chronic respiratory diseases, and lung cancer. Airborne Diseases Many diseases can arise after exposure to airborne particles, including: the common cold, which can develop from a rhinovirus chickenpox, caused by the Varicella zoster virus mumps, caused by a paramyxovirus measles, caused by another paramyxovirus whooping cough, a bacterial infection caused by Bordetella pertussis COVID-19, caused by the SARS-CoV-2 virus aspergillosis, caused by the Aspergillus fungus tuberculosis (TB), caused by the bacterium Mycobacterium tuberculosis anthrax, a bacterial infection resulting from contact with Bacillus anthracis spores diphtheria, a bacterial infection caused by Corynebacterium diphtheriae meningitis, which can result from exposure to certain bacterial, viral, or fungal particles… Pandemics in the World History Plagues and epidemics have ravaged humanity throughout its existence, often changing the course of history. Throughout the course of history, disease outbreaks have ravaged humanity, sometimes changing the course of history and, at times, signaling the end of entire civilizations. Here are 20 of the worst epidemics and pandemics, dating from prehistoric to modern times…> 27 The Black Death: 1346-1353 The Black Death traveled from Asia to Europe, leaving devastation in its wake. Some estimates suggest that it wiped out over half of Europe's population. It was caused by a strain of the bacterium Yersinia pestis that is likely extinct today and was spread by fleas on infected rodents. The plague changed the course of Europe's history. Studies suggest that surviving workers had better access to meat and higher- quality bread. The lack of cheap labor may also have contributed to technological innovation. https://populationeducation.org/cont ent/world-population-video 28  Great Plague of London: 1665-1666 The Black Death's last major outbreak in Great Britain caused a mass exodus from London, led by King Charles II. The plague started in April 1665 and spread rapidly through the hot summer months. Fleas from plague-infected rodents were one of the main causes of transmission. By the time the plague ended, about 100,000 people, including 15% of the population of London, had died. 29  Flu pandemic: 1889-1890 In the modern industrial age, new transport links made it easier for influenza viruses to wreak havoc. In just a few months, the disease spanned the globe, killing 1million people. It took just five weeks for the epidemic to reach peak mortality. The earliest cases were reported in Russia. The virus spread rapidly throughout St. Petersburg before it quickly made its way throughout Europe and the rest of the world, despite the fact that air travel didn't exist yet.! 30  Spanish Flu: 1918-1920 An estimated 500 million people from the South Seas to the North Pole fell victim to Spanish Flu. The flu's spread and lethality was enhanced by the cramped conditions of soldiers and poor wartime nutrition that many people were experiencing during World War I. Despite the name Spanish Flu, the disease likely did not start in Spain. Spain was a neutral nation during the war and did not enforce strict censorship of its press, which could therefore freely publish early accounts of the illness. As a result, people falsely believed the illness was specific to Spain, and the name Spanish Flu stuck. 31  H1N1 Swine Flu pandemic: 2009-2010 The swine flu pandemic was caused by a new strain of H1N1 that originated in Mexico in the spring of 2009 before spreading to the rest of the world. In one year, the virus infected as many as 1.4 billion people and killed thousands people, according to the CDC. Interestingly, the swine flu pandemic primarily affected children and young adults, and 80% of the deaths were in people younger than 65. 32 Influenza (flu) vaccines (often called “flu shots”) are vaccines that protect against the four influenza viruses that research indicates will be most common during the upcoming season. Most flu vaccines are “flu shots” given with a needle, usually in the arm, but there also is a nasal spray flu vaccine.  Adult Immunization Schedule (Turkey) Vaccine 1 Booster dose per 10 year Measles-Mumps-Rubella (MMR) 1-2 doses per year 3 doses per year 1 dose per year 1 dose per year 1-2 doses per year 1 dose per year 2 doses per year Chicken pox 2 doses per year 1 or more doses 5/8/2024 38 COVID-19 Pandemic On 31 December 2019, the Wuhan Municipal Health and Health Commission reported a cluster of pneumonia cases of unknown a etiology. Further investigations identified a novel coronavirus as the causative agent of the respiratory symptoms for these cases. The outbreak has rapidly evolved, affecting other parts of China and other countries. 41  COVID-19 Pandemic Globally, as of 3 May 2023, there have been 765.222.932 confirmed cases of COVID-19, including 6.921.614 deaths, reported to WHO As of 4 May 2023, a total of 13.349.209.463 vaccine doses have been administered. These trends should be interpreted with caution as several countries are progressively changing their COVID-19 testing strategies, resulting in lower overall numbers of tests performed and consequently lower numbers of cases detected. 42  Conclusion; Stopping Transmission of Infection We can prevent transmission in many cases. The only way to prevent infection is to STOP the transmission of microorganisms. The best way to prevent infections by following standard precautions. 08/05/2024 52  Infection Prevention What are the most effective 2 elements to stop transmission / prevent infections ? 08/05/2024 53  Standard Precautions 1. Wash your hands 2. Wear gloves 3. Wear eye protection or faceshields 4. Wear gowns 5. Prevent injuries with sharps 6. Correctly process instruments and client care equipment 7. Maintain correct environmental cleanliness and waste-disposal practices 8. Handle, transport and process used/soiled linens correctly! 08/05/2024 54  Infection Prevention 08/05/2024 55  Thank you [email protected] Risk factors for Covid-19 disease transmission and severity.