ED EPIDEMIOLOGY OF IFECTIOUS DISEASES i MUDr. Marie Kolářová, CSc. Ústav ochrany a podpory zdraví LF MU Spring 2020 Epidemiology The word "epidemiology" is derived from the Greek words: -epi "upon", demos "people" and logos "study". Epidemiology in its modern form is a relatively new discipline and uses quantitative methods to study diseases in human populations to inform prevention and control efforts. MUNI med Epidemiology is the study (includes: surveillance, observation, hypothesis testing, analytic research and experiments) of the distribution (refers to analysis of: times, persons, places and classes of people affected) Distribution of COVID-19 cases worldwide, as of 19 February 2020 (according to the applied case definition in the countries) 16000 Number of cases 14000 -12000 10000 8000 - 6000 - Outside China «China Epidemiology is and determinants (include factors that influence health: biological, chemical, physical, social, cultural, economic, genetic and behavioural) COVID-19 WHO recently announced that the official name for the disease causing the 2019 novel Coronavirus outbreak is COVID-19. med Epidemiology is of health-related states (refer to: diseases, causes of death, behaviours such as use of tobacco, positive health states, reactions to preventive regimes and provision and use of healths services) -Confirmed cases global: 75,725 -Recoveries 16,330 44 days since the -Deaths 2,128 virus was discn^ex! med Case definition for surveillance The case definitions are based on the current information available and may be revised as new information accumulates. Countries may need to adapt case definitions depending on their own disease situation. Suspect case A. Patients with severe acute respiratory infection (fever, cough, and requiring admission to hospital), AND with no other etiology that fully explains the clinical presentationl AND at least one of the following: • a history of travel to or residence in the city of Wuhan, Hubei Province, China in the 14 days prior to symptom onset, or • patient is a health care worker who has been working in an environment where severe acute respiratory infections of unknown etiology are being cared for. B. Patients with any acute respiratory illness AND at least one of the following: • close contact2 with a confirmed or probable case of 2019-nCoV in the 14 days prior to illness onset, or • visiting or working in a live animal market in Wuhan, Hubei Province, China in the 14 days prior to symptom onset, or • worked or attended a health care facility in the 14 days prior to onset of symptoms where patients with hospital-associated 2019-nCov infections have been reported. Probable case Probable case: A suspect case for whom testing for 2019-nCoV is inconclusive3 or for whom testing was positive on a pan-coronavirus assay. Confirmed case A person with laboratory confirmation of 2019-nCoV infection, irrespective of clinical signs and symptoms. 6 MUNI med COVID-iQ Disease caused by the SARS-C0V-2 virus Novel coronavirus Coronaviruses are viruses that circulate among animals but some of them are also known to affect humans. The 2019 novel coronavirus was identified in China at the end of 2019 and is a new strain that has not previously been seen In humans. ac6c Prevention When visiting China Symptoms . G 2 ER $G COUGH (JO DIFFICULTY BREATHING > MUSCLE PAIN nm Avoid contact with sick people Avoid visiting markets and places /uu> where animals are handled yf^j Avoid contact with animals, their excretions or droppings Wash your hands with soap and water § Apply general rules governing food hygiene Wherever you travel apply general hygiene rules Transmission VIA RESPIRATORY DROPLETS 2-14days estimated Incubation period ♦ « MUNI med ecdc.europa.eu/en/novei-coronavlnischtna Epidemiology is in specified populations, (include those with identifiable characteristics, such as occupational groups) MUNI med Coronavirus Disease 2019 Information for Travel Travelers from China Arriving in the United States Interim Guidance for Airlines and Airline Crew: Ship Sanitation Certificate Information Information for Healthcare Professionals •Healthcare Personnel with Potential Exposure Guidance •Inpatient Obstetric Healthcare Guidance •Coronavirus Disease 2019 (COVID-19) and Pregnancy 9 MUNI med Epidemiology is r i and the application of this study to control health problems (the aims of public health - to promote, protect, and restorre health!!!! World experts and funders set priorities for COVID-19 research They discussed all aspects of the outbreak and ways to control it including: - the natural history of the virus, its transmission and diagnosis; - animal and environmental research on the origin of the virus, including management measures at the human-animal interface; - epidemiological studies; - clinical characterization and management of disease caused by the virus; - infection prevention and control, including best ways to protect health care workers; - research and development for candidate therapeutics and vaccines; - ethical considerations for research; - and integration of social sciences into the outbreak response. MUNI med Epidemiology is the study (includes: surveillance, observation, hypothesis testing, analytic research and experiments) of the distribution (refers to analysis of: times, persons, places and classes of people affected) and determinants (include factors that influence health: biological, chemical, physical, social, cultural, economic, genetic and behavioural) of health-related states (refer to: diseases, causes of death, behaviours such as use of tobacco, positive health states, reactions to preventive regimes and provision and use of healths services) in specified populations, (include those with identifiable characteristics, such as occupational groups) and the application of this study to control health problems (the alms of public health - to promote, protect, and restorre health! S! Surveillance represents a number of long-term and complex programmes, in which experts of various medical fields participate together, for example lu epidemiologists, microbiologists, hygienists, z clinicians etc. fj Other non-medical personnel, such as statisticians, □ vets and ecologists, may also participate alongside En medical personnel. w The epidemiologist is usually the initiator and organiser of the program. Surveillance was initially started in the field of infectious diseases. MUNI med The systematic ♦♦♦ collection, lu ♦♦♦ analysis, z ❖ interpretation, and J ♦> dissemination of health data on an ongoing w basis, 9c to gain knowledge of the pattern of disease occurrence and potential in a community, in order to control and prevent disease in the community. MUNI med Surveillance is put into effect in three successive stages: * Obtaining the necessary data such as the number of sick, the number of dead, data from microbiological laboratories on circulation and qualities of etiological agent, q clinical information on symptomatology of individual diseases, monitoring of vaccination and collective immunity of population, monitoring of infections with animals, and data of □ natural sciences on vectors. Ér * Analysis of collected data, including evaluation of information and suggestion of measures. Long-term surveillance gives the possibility of making a prognosis of the occurrence of a given disease for the future. * Guaranteeing qualified information to all concerned people who can further use it for improvement of their o^ij) N j measures and theories. m e d co Sporadic disease Endemic disease Epidemic(outbreak) Pandemic disease Zoonosis, epizootic and enzootic Eradication Elimination Nosocomial infection Attack rate Opportunistic infection o o R -Viruses < CO < o 17 H epatitis; Ä*.RNtA #|u s - Fungi - Prions -Spirochetes - Parasites CONSEQUENCES Those affected lose the ability to think and to move properly and suffer from memory loss. It is always fatal, usually within one year of onset of illness. How Creutzfeldt-Jakob disease works CAUSE Creutzfeldt-Jakob disease is caused 'by abnormal proteins called prions that are not killed by standard methods for sterilizing surgical equipment. NORMAL DISEASE HUMAN CAUSING PROTEIN PRION As prions build up in cells, the brain slowly shrinks and the tissue fills with holes until it resembles a sponge. Ebola SOURCES: World Health Organization, Centers lor Disease Control and Prevention, National Institute of Neurological Disorders and Stroke, AP oavio butlir. cmioui estiban. iavier Sarcoptes scabiei co E °£ C (/) 2"E E o 26 o £ C3 U E o o Many parts of the body are colonized by normal flora, which can be the source of endogenous infection. Large numbers of micro-organisms are found in moist areas of the skin (e.g. the groin, between the toes), the upper respiratory tract, the digestive tract (e.g. the mouth, the nasopharynx), the ileum and large intestine, the anterior parts of the urethra and the vagina. Other routes are interhuman transmission of infections and exposure to exogenous contamination. Healthy newborn = germ-free organism Gradual colonization: * Skin - when passing through the mother's birth paths * breathing paths - at first breath * GIT - at first swallowing ... ended until the 8th day Permanent colonization, eumicrobia, Types of bacteria event, fungi (never virus!) are for a given system: * characteristic, * non-pathogenic, * constant composition Constantly restored balance between the host and the micro-oraanism. Balance distorts: a) external changes (chemical, physical) b) host properties (hormonal, immune status, drugs - ATB, corticosteroids, cytostatics) The importance of physiological microflora + affects digestion, absorption, peristalsis + produces vitamins + protection of skin and mucous membranes from microbes with higher pathogenicity Negative influence: - the risk of endogenous infections in immunosuppressed persons - complications of interpretation of serological examinations) Parasitism - survival and multiplication of host microbes with host abuse Comensalism - the microbe uses the host but does not damage it Symbiosis - hosts and microorganisms benefit from coexistence Carriage - the state of immunobiological balance The agent of infection - important characteristic: infectivity - capacity to multiply in host pathogenicity - capacity to cause disease in host virulence - pathogenicity in a specific host immunogenicity - capacity to induce specific and lasting immunity in host antigenic stability - can induce long-life immunity resistance - in environment The viability of micro-organisms and their survival in the external environment depends on: □ on their properties and □ on the environment in which they are located, (by combining - low temperatures, - lower humidity, - absence of toxic substances, and - the presence of colloidal substances that have a protective effect). Organisms vary in their capacity to survive and to withstand adverse environmental conditions, for example: * heat, cold, dryness. Sporo-forming organisms, such as tetanus bacilli which can survive for years in a dormant state, have a major advantage over an organisms like the gonococcus which survive for only a very short time outside the human host. w> Infection is the entry and development or multiplication g of an infectious agent in the body of man or animals. 8 An infection does not always cause illness. (A o There are several levels of infection (Gradients of £ infection): = ❖ Colonization (S. aureus in skin and normal 0 nasopharynx) ■3; ❖ Subclinical or inapparent infection (polio) 1 ❖ Latent infection (virus of herpes simplex) g» ❖ Manifest or clinical infection For all pathogens are important infective and lethal doses. Virulence factors affecting their pathogenicity: 1. Pilli that ease attachment 2. Covers that interfere with phagocytosis 3. Exotoxins 4. Endotoxins 5. Proteases that degrade antibodies 6. Ability to change the antigens that escape the fragments (/) (D "O ■ n E > (/> (D i E O % hodnot dospělých ■ Trans placenta mě; prenesený IgG 20 30 Narození Gestační věk (týdny) 1 / L. Věk (roky) 10 Šedivá A. Čes.-slov. Pediat, 2005, roč.60, č.11, s. 617-624 Sites exposed to exogenous contamination Conjunctiva Nasopharynx Mouth Trachea, esophagus Skin Lungs, bronchi Stomach Intestine Urinary tract Genital tract Rectum (/> o o 0 1 E 0) c/> o o CD (0 o THE CAUSATIVE AGENT OF INFECTION (bacteria, viruses, fungi, prions, protozoa) 1. the resence of rezervoir (source) of infection man, animal at the ende of incubation period acute stage caners 2. the way of transmission ai direct contact 3. the susceptibility concerned touching, kissing or sexual intercourse (Staphylococcus spp., Gonococcus spp.,HIV...), - from mother to fetus (VHB, VHC, HIV, listeria, rubella, cytomegalovirus...) B/ indirect contact - inhalation of droplets containing the infectious agents (TBC, measles, influenza...) - ingestion of food or water that is contaminated (salmonella, giardia, Norwalk virus, VHA....) - b n by insects (malaria, borellia....) of the population or its individual members to the organism Host factors: age,nutrition, genetics immunity- natural (nonspecific), - acquired THE INFECTION = 1. prezence of rezervoir (source) of infection is the site or sites in which a disease agent normally lives and reproduces. May be classified as: - human - at the ende incubation period, - if are ill, - reconvalescent, - carriers - healthy, chronic ill - animals - at the ende incubation period, carriers - healthy, |§ reconvalescent, chronic ill Droplets from respiratory tract (nasopharyngeal secretion) - adenoviruses, coronaviruses, ortomyxoviruses (flu) RSV, rhinoviruses, staphylococcus, streptococcus, meningococcus, Bordetella pertusls, Mycoplasma pneumoniae, Mycobacterium tuberculosis......... Saliva -VHB, HIV, CMV, EBV, herpes virus hominis typ 1,2, morbilli, rubella virus..... Faeces - Enteroviruses (VHA, poliomyelitis), VHE, Coxsackie viry, adenoviruses, Enterobacteriacee (E. coll, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus spp., Citrobacter, Enterobacter, Serratia apod, Listeria monocytogenes, Clostridium difficile, Clostridium tetanl, Pneumocystis carinii............ BlOOd, plasma, blOOd products - VHB, VHCVHA (short viremia), HIV, CMV, rare EBV, Plasmodium malarlae , Toxoplasma gondii....... Urine - morbilli virus, CMV, VHB, papovaviry, Listeria monocytogenes, Kandidy....... Tears, eye secretion -VHB, HIV, adenoviry, Enterovirus typ 70, Coxsackie A 24, Staphylococcus aureus, hemophfilus, pneumokoky, moraxely, chlamydie..... Vaginal secretion - HIV, VHB, vzácně VHC, herpes virus hominis typ 1,2, Streptococcus agalactlae, Neisseria gonorrhoea, Haemophilus Ducreyi, Treponema pallidum, Trichomonas vaginalis, Chlamydia lymfogranulomatosis, Chlamydia trachomatis.. Sperma -VHB, HIV, rare VHC, CMV..... UOr — various agents of meningitis o'E (A o o cd s_ ^ cd CM A/ direct contact touching, kissing or sexual intercourse (Staphylococcus spp., Gonococcus spp.,HIV...), - vertical transmission - from mother to fetus (VHB, VHC, HIV, listeria, rubella, cytomegalovirus...) B/ indirect contact - inhalation of droplets containing the infectious agents (TBC, measles, influenza...) - ingestion of food or water that is contaminated (salmonella, giardia, Norwalk virus, VHA....) - biological transmission by insects (malaria, borellia____) Host factors: co Non specific immunity Q § .co External barrier: Barrier action (natural barrier) _ 55 e en skin , mucosa O 3 oo P o £ o y o Secretion of skin and mucosa 5 cl§)cd Accessory organ ° o ^ Internal barrier: placenta, blood-brain barrier "o Jz 2 Phagocytosis Q co Humoral action n — - Complement, Lysozyme, Fibronection, Cytokines. -■^ CD o co Specific immunity ^ o cd co Humoral immunity I— CO C~ ( 7 ^ _ o Immunoglobulin: IgG, IgM, IgE, IgA, IgD cd § Jz Cell mediated immunity 1. entry of the etiological agent to a susceptible individual; 2. adherence of the agent to the target tissue; 3. reproduction and invasion; 4. host damage by toxins or other mechanisms; 5. exclusion of the agent through some of the biological materials 6. possible survival of agents for a long time in an inanimate external environment co 0) CO CO CD CO CO 0 1 o CD o CO CO CD a> o CO Q- C/) 0) C/) CO 0) C/) C/) o o o o 0) > 37 Isolation of patients: - Dpt. of infectious diseases, - „high degree of isolation" (ebola) - at home, - barriers nursing technique SOURCE OF INFECTION SUSCEPTIBLE ORGANISM HANDWASHING, DISINFECTION OF HANDS LINEN WASHING, CLEANING GOOD PREPARING OF FOOD, SAFE WATER. DISINFECTION STERILIZATION - acquired (vaccination) Principles of Vaccination Active immunisation A live or inactivated substance (e.g., a protein, polysaccharide) capable of producing an immune response is administered to the organism to target specific antibodies against that antigen. Protein molecules (immunoglobulin) produced by B lymphocytes to help eliminate an antigen Passive immunisation Transfer of antibodies produced by one human or other animal to another. Temporary protection Transplacental most important source in infancy If the epidemiology is know, we can interfere with transmission: ..BREAKING THE CHAIN OF INFECTION" Different infections have different epidemiologies and thus require different methods of control In the practical part it is preoccupied with preventive measures repressive measures related to infectious diseases The distribution of the smallpox rash is usually similar to that shown here, o It is most dense on the to face, arms and hands, legs ~ and feet. 2 The trunk has fewer pocks 0 than the extremities. x o CO E CO 44 Smallpox is a disfiguring disease. Three out of ten cases may die. It is caused by variola virus. The disease is spread by secretions from the patient's mouth and nose, and by O material from pocks or scabs. It is transmitted directly from one person to the next. Close contact with patients, or their X q clothing or bedding, is thus required for CO CO CD _ infection. CO A patient who has developed the ^ distinctive symptoms of smallpox will CO have been exposed to the virus about two weeks previously. 45 Face lesions on boy with smallpox. Public Health Images Library (PHIL) ID # 3. Source: CDC/Cheryl Tyron Smallpox recognition card, c.1973, courtesy Dr. Damodar Bhonsule, Panjim, Goa, India. Smallpox lesions on skin of trunk. Picture taken in Bangladesh, 1973. Public Health Images Library (PHIL) ID # 284. Source: CDC/James Hicks X o Q. as c/> Q X Q> o O icat 0) N rad A key figure in the global eradication program smallpox was prof. MUDr. Karel Raska, MD., who drove in the sixties division Communicative Diseases of the WHO Secretariat in Geneva. He promoted the establishment of a new, independent units "Eradication of smallpox, and ensure its initial financial and material support, not only in Geneva, but also in regional offices of WHO. With its support of the program also attended the 20 Czechoslovak health professionals (14 Czechs and Slovaks 6), mainly epidemiologists. They participated in both the preparation methodology and procedures, thus working directly in infested areas, Rural vaccinator in United Provinces, British India, c.1930, private collection of Dr. Sanjoy Bhattacharya MULTIPUNCTURE VACCINATION BY BIFURCATED NEEDLE Variola virus, which causes smallpox, was once the scourge of the world. This virus passes from person to person through the air. A smallpox infection results in fever, severe aches and pains, scarring sores that cover the body, blindness in many cases, and, often, death. There is no effective treatment. Although vaccination and outbreak control eliminated smallpox in the United States by 1949, the disease still struck an estimated 50 million people worldwide each year during the 1950s. In 1967, the World Health Organization (WHO) launched a massive vaccination campaign to rid the world of smallpox —and succeeded. The last natural case of smallpox occurred in Soriialiain 1977. AN Maow Maalin, cook twenty-three of the hospitalsirTThe Somali Merce.He contracted when he showed the path of the ambulance chauffeur who drove two sick children to camp insulation. In 1978 was ill photographer Medical School in Birmingham, England. She was killed by a virus that escaped from a neighboring lab. Mr. John Wickert, of the World Health Organization, with the last person to have contracted - and survived - naturally occurring smallpox in Somalia. Variola, České země, 1892-1937, nemocnost a úmrtnost na 100 000 obyvatel 120 -i 100 - 80 60 40 - 20 - nemocnost úmrtnost 1919 - zavedení povinného očkování a preočkovaní * ♦ I 1 » I 1 » * ♦ I 1T1TTT* g St U 8 8 U S ? 2 ? í ? Í5 S K U S S Sí; 00 CO 00 CO 0t 0& 0> ^> 0^ 0fc ^ (7) ^> 0% 0% 0% 0% 0$ 0í 0% 0% m Statní zdravotní ústav Smallpox eradication was officially announced at the 33rd General Assembly WHO 8. May 1980. Milestones in the eradication of smallpox 1789 Edward Jenner invents a smallpox vaccine. 1966 The World Health Organization (WHO) launches a massive global campaign to eradicate smallpox. 1972 Smallpox vaccinations are discontinued in the United States. 1975 and 1977 The last cases of the two known variants of smallpox occur in the world, in Bangladesh and Somalia. 1978 Two people are sickened in a lab accident in England; one dies. 1980 The WHO declares smallpox eradicated. 1991 Smallpox virus DNA is mapped. 1999 The WHO sets this deadline, by which remaining lab stocks of the virus are to be destroyed. The deadline will be postponed again and again. 2003 Millions of doses of vaccine are produced to hedge against a biological attack. 2011 WHO's decision-making body will meet in May to again vote on whether to kill the remaining live viruses.