Chapter Two: Human Health PDF

Chapter Two: Human and health Resource u Chapter Two u Science and Life textbook Learning objectives u Differentiate between health and disease concepts u Categorize the type of diseases u Name the organisms causing infectious diseases u Explain how the infectious disease is tran...

Chapter Two: Human and health Resource u Chapter Two u Science and Life textbook Learning objectives u Differentiate between health and disease concepts u Categorize the type of diseases u Name the organisms causing infectious diseases u Explain how the infectious disease is transmitted and its effects on the body, u Distinguish between innate immunity and adaptive immunity u Compare between different types of vaccine u Define the genetic disease and Differentiate between thalassemia and sickle cell anemia. Definition of health(WHO) u Health: a state of complete physical, mental and social well being which is more than just absence of disease u The World Health Organization defines health as more than just physical well-being; it includes social, personal, and emotional factors for overall well-being. Disease – Oxford medical dictionary1 u A disorder is a health condition with a specific cause (which might or might not be known) and clear signs or symptoms. It's when the body doesn't work properly, but not because of a direct physical injury.  Signs & symptoms u Each disease is associated with a set of signs and symptoms; both terms are different from each other. u Signs: Changes in body function that a physician can detect and measure, such as elevated blood pressure u Symptoms: What a patient reports experiencing but cannot be measured, e.g. lack of sleep, headache Measure health u A way to measure health is to look at a population’s health status by using morbidity and mortality rate. u Morbidity: is the disability rate, and the term is often used to mean illness or disease u Mortality: mortality rate is the death rate, the incidence of deaths per unit of time, most often per year, in a population Disease classification according to time u According to healing time Acute: a disease in which the person may recover quickly Chronic: lasts for a very long time Communicable diseases or infectious diseases u Diseases that are caused by germs. u Transmitted from one person to another either direct or indirect transmission u E.g., Covid-19, Influenza, Cholera  Classification of disease Communicable Non-communicable diseases or diseases infectious diseases Genetic or Degenerative Metabolic disease inherited diseases disease Non-communicable diseases: u Not transmissible u Happen because of genetic, physiological, environmental, and behavioral factors u Last a long time u E.g., Cardiovascular disease, stroke, certain cancer, asthma Genetic or inherited diseases: u Caused by defects in genes or chromosomes of people u When these defects occur at birth  congenital that may or may not have been inherited. u E.g., Down syndrome, Thalassemia, sickle cell anemia Degenerative disease u These disorders cause problems in tissues, organs, or body structures. u In neurodegenerative diseases, the nervous system breaks down over time. u Examples include Parkinson’s disease and Alzheimer’s disease. Metabolic disease u Caused by abnormal chemical reactions in body that disrupt metabolism u E.g., Diabetes, hypertension  Microbial concept of infectious disease u Microorganisms, also called microbes, are present in air, food and plants, and are found on all surfaces. Viruses u Very small, ranging in size from 20-300 nm u Are not cells (don’t have organelles ) u Cannot reproduce by itself because has to find a host (target) to control that cell’s machinery and reproduce. u E.g., Smallpox, Hepatitis, SARS, AIDS Bacteria u Size: 0.4 mm to 2.0 mm. u Prokaryotic organisms u Most can reproduce and grow independently without needing hosts u E.g., Cholera, Tuberculosis, Pneumonia  Protozoa (parasite) Unicellular, has true nucleus Infect humans through contaminated water and food or carried by vectors such as mosquitoes and monkeys. E.g., Malaria (caused by plasmodium carried by mosquitoes Transmission of disease u classification of infectious disease according to prevalence within the community ( book page 53) 1. Endemic – ‫مرض‬ ‫متوطن‬ 2. Epidemic – ‫وباء‬ 3. Pandemic – ‫جائحة‬ Transmission of disease – direct vs indirect Direct transmission Indirect transmission u Human physical contact e.g. hand u Touching the object contaminated with shakes, saliva (respiratory droplets) pathogens when an infected person etc. coughs or sneezes. u Blood transfusion e.g. hepatitis u Some pathogens travel through air & stay there for a long time with aerosols. u Mother to unborn child through placenta or milk e.g. AIDS u The disease is transmitted through vectors e.g. mosquitoes, lice, flies, u Zoonotic infections are transmitted and fleas. through animals directly to humans, like cats and dogs. u Diseases can be transmitted indirectly through contaminated food and water Infection Diseases Name of disease Name and type of pathogen Source of the disease Way of transmission (Direct and indirect way) Incubation period Life cycle (Entry point ) Sign and symptoms Diagnosis Treatment  Infection disease Respiratory Digestive system system disease disease Bacterial Bacterial Viral disease Viral disease disease disease Tuberculosis SARS MERS Covid19 Rotavirus Cholera disease Respiratory system diseases Viral disease – Coronavirus u Coronavirus – belong to family Coronaviridae u Named – because of the crown-like spike on their surface  Respiratory system disease Viral disease SARS MERS Covid19 Sever Acute Middle-East Novel Respiratory Respiratory Coronavirus- System System 19 SARS – Sever acute respiratory Middle East Respiratory Syndrome coronavirus u Zoonotic virus u Found in the one-humped camel u Transmitted by uncooked consuming camel meat or milk, and contacting camel waste. u Virus transmission via direct contact like when caring for a patient. Life cycle u Incubation period = 2-14 days u The virus affected the lower respiratory tract and damages parts of lung u Protein on the lung cells that allow the virus to enter inside the cells called DDP4 or CD26) u The protein widely distributed inside the body such as u Mild symptoms: Fever, tremor, dry cough, muscle pain (myalgia) and gastrointestinal symptoms like diarrhea, vomiting, nausea, stomach ache. u Severe symptoms: Respiratory failure, acute respiratory distress syndrome, organ failure, septic shock, which eventually leads to death Diagnosis u Real-time Polymerase Chain Reaction (RT-PCR) is the most accurate suitable for detecting all known MERS-CoV strains in humans and dromedary camels Pandemic u World Health Organization in March 2020 to declare that COVID-19 became a pandemic. u Currently more than 612 million infections (0.6 billion) and 6.5 million deaths u Spreads very fast and through a huge portion of the population u Example COVID 19 Stages of spread u - Local: Cases start in a seafood market. u - Community: Spread through interpersonal contact within communities and families. u - Widespread: Rapidly spreads across China and worldwide due to large population movement. Transmission: Direct contact vs indirect u Direct contact u Indirect contact u The virus spreads through droplets u The virus spreads by touching when an infected person coughs or contaminated surfaces, then sneezes. transferring it to the mouth, eyes, or nose. u These droplets travel up to 3 feet and can land on the mouth, nose, or eyes of people nearby.. Incubation u The incubation period of COVID-19 is 5 - 6 days. u It can be as long as 14 days Symptoms - mild u The most common symptoms include dry cough, fever, and u tiredness. u The less common symptoms include aches and pains, sore throat, diarrhea, conjunctivitis, headache, loss of taste or smell, a rash on the skin, and discoloration of fingers or toes. Symptoms - moderate u breathing difficulty and tachypnea (abnormally rapid breathing). Symptoms - severe u hypoxemia (low level of oxygen in the blood), acute respiratory distress syndrome (deteriorating u respiratory failure), arrhythmia (a problem with the rate of the u heartbeat), and septic shock due to multi-organ dysfunction. Tuberculosis u One of the most prevalent infectious diseases in the world u One of the first ten causes of death around the world u 10 million people infected in 2019 with 1.4 million deaths Countries where most TB is found u Bangladesh u China u Indonesia u Nigeria u Pakistan u Philippines u South Africa Transmission u Spread through air u Person to person when infected person coughs, sneezes and someone else will inhale u The particles have the bacteria and can stay for several hours u Silent, latent infection (1-2 Years) and can activate with other diseases, malnutrition, HIV infection u Progressive, active infection u Bacteria enters human body u White blood cells attack Signs and symptoms u Prolonged cough u coughing blood u Chest pain u weakness or fatigue u weight loss u night sweats Diagnosis u Sputum sample u Tuberculin Skin Test (TST): u Radiography X - Ray Treatment and prevention u Tuberculosis is treatable and can take 6 months to treat with antibiotics u Patients sometimes stop taking the medications and the bacteria DNA can mutate leading to drug resistance and infecting others with such special bacteria Digestive system diseases u Rotavirus u Cholera Rotavirus u Causes viral enteritis, u There are seven groups of rotavirus (A through G) u Human disease results from group (A) Transmission u Fecal-oral route u Contact with contaminated water, food or objects u Usually, infection in adults is due to contact with children infected with the virus, and group B rotavirus is the most common among adults. Infection u Rotaviruses infect small intestine, grow inside intestinal cells and damage these. u Incubation period 1 to 3 days u Range from asymptomatic to acute gastroenteritis leading to life threatening dehydration from severe diarrhea (especially children) u Fever, abdominal pain, vomiting u Mild cases 3 – 8 days Diagnosis u Detect the virus in the infected child's stool are antigen u Enzyme u Immunoassays (EIAs) or Polymer Chain Reaction (PCR) tests. u PCR is most sensitive method of u detection. Treatment u No antiviral for treatment u Supportive treatment with fluids and electrolytes u Oral rehydration therapy u Sanitation and sterilization of water to control disease Immunity u The host body’s ability to fight disease-causing germs is u called immunity. u Immunity includes different defense lines. u Types of immunity u innate immunity u adaptive immunity  Immunity Acquired Innate (adaptive) Active Passive Artificially Naturally acquired acquired Innate u non-specific type of defense, present from birth and works against invading agents. u includes many barriers u Physical barriers: prevents entry of germs such skin, mucous coating of the epithelium lining respiratory system, and digestive system. u Chemical barriers: gastric juice, saliva in the mouth, and tears all play a vital part in preventing germs from growing and causing diseases. u Cellular barriers: certain types of cells e.g. white blood cells swallow up the infection causing microorganisms. u Molecular barriers: production of substances to destroy or prevent microbes' invasion. u Inflammation: Redness, swelling, and temperature increase in the tissues at the infection sites are signs of resistance to disease-causing germs. u Fever: High body temperature eliminates invading germs by deactivating the toxic substances they produce. Acquired immunity u Result of exposure to pathogens such as viruses and bacteria. u It can be acquired by stimulating the immune system using injection of vaccine that has the germs' antigens. u So acquired immunity is built either naturally or artificially Types of passive immunity u Naturally occurring: The body acquires it because of natural exposure to pathogens. u During the disease, immune system responds to molecules called antigens on the invading germs, so cells called T lymphocytes and B lymphocytes are activated, which produce antibodies to eliminate germs u Artifically induced: By injecting body with antigen that causes the disease in the form of a vaccine (weak, dead, or inactivated) and stimulate the immune system. u So if exposed again to the same pathogen, immune system remembers the antigen because the body contains lymphocytes T and B, which play a crucial role in eliminating and remembering all kinds of germs that caused the disease earlier. Vaccines u Substances containing the antigen that stimulates the immune system. Attenuated vaccine u using a weak form of the germs that cause the disease, then the pathogens cannot reproduce or grow. u Gives strong immunity and a long-term response. u Only one or two doses of most live vaccines can provide life-long u protection against germs and the disease they cause; u E.g., Rotavirus, Smallpox, Measles, Mumps. Inactivated vaccine u Dead version of the germs that cause the disease can be used. This type of vaccine does not provide as strong protection as an attenuated vaccine mechanism of action for an inactivated vaccine u May need many doses u Eg., hepatitis A, influenza, u polio. Sub unit, recombinant vaccine u Using a part of the germs such as the protein, sugar, and capsid (covering the germ). u Gives excellent immune response. u Can be given to all individuals including immunodeficient or chronically ill patients u E.g., hepatitis B, whooping cough, meningococcal disease. Genetic disease u Kind of disease caused by defects in the genes or chromosomes of individuals. u These mutations or defects can be due to an error in DNA replication or environmental factors, such as radiation, smoking which causes changes in the DNA. Thalassemia Genetic related disease in the blood Sickle cell anemia u Inherited blood-related disorder resulting from the aggregate of abnormal hemoglobin molecules (hemoglobin S) inside the red blood cells, making them sickle-shaped u Sickle cells die within 20 days, and since the bone marrow cannot replenish the dying cells quickly enough, a decrease in the number of red blood cells happens. u Very rigid, causing them to become stuck in the narrow capillaries, which reduces blood flow to various parts of the body and results in organ damage, especially the spleen Symptoms u Some will have mild and others have repetitive vascular occlusive crises. u Start at age 6 – 12 months u Shows as hemolytic anemia; paleness, fatigue, jaundice, and irritability. u Crises.