IHS

• Communicable diseases are spread from one living thing to another or through the environment
• Pathogens are the causes of communicable diseases
• Infection is a condition that occurs when pathogens enter the body, multiply, and damage body cells
• Pathogens include viruses, bacteria, fungi, protozoa, and rickettsia
• • Susceptible Host: individuals who are vulnerable to infection due to various factors
• The chain of infection for communicable diseases consists of:

  • Agent: the pathogens that cause communicable diseases
  • Reservoir: the habitat where the agent normally lives and multiplies (human, animal, environmental)
  • Portal of Exit: the path by which a pathogen leaves its host (respiratory tract, gastrointestinal tract, blood, skin)
  • Mode of Transmission: direct (contact, droplet spread) and indirect (airborne, vehicleborne, vectorborne)
  • Portal of Entry: the manner in which a pathogen enters a susceptible host (respiratory tract, gastrointestinal tract, blood, skin, mucous membrane)
• Human reservoirs for communicable diseases include carriers who can transmit the pathogen to others:

  • Asymptomatic carriers: infected individuals who never experience symptoms
  • Incubatory carriers: individuals who can transmit the agent during the incubation period before clinical illness begins
  • Convalescent carriers: those who have recovered from their illness but can still transmit the pathogen
  • Chronic carriers: individuals who continue to harbor a pathogen for months or years after initial infection
• Animal reservoirs for diseases are transmitted from animal to animal, with humans as incidental hosts

  • Zoonosis refers to infectious diseases transmissible from vertebrate animals to humans
  • Environmental reservoirs include plants, soil, and water that serve as reservoirs for some infectious agents
• Modes of transmission for communicable diseases:

  • Direct transmission: person-to-person (skin-to-skin contact, kissing, sexual intercourse) or contact with soil or vegetation harboring infectious organisms
  • Droplet spread: spray with large aerosols produced by sneezing, coughing, or talking
  • Indirect transmission: through suspended air particles (airborne), inanimate objects (vehicles), or animate intermediaries (vectors)
• Preventing communicable diseases involves physical and chemical barriers as the body's first line of defense:

  • Physical barriers include skin and mucous membranes
  • Chemical barriers include enzymes in tears
  • The immune system plays a crucial role in defense
• Common communicable diseases include:

  • Measles: transmitted primarily by airborne respiratory droplets
  • Tuberculosis: transmitted from person to person through the air (airborne)
  • Hepatitis B: transmitted through exposure to infected blood or body fluids, mother to child at birth
• Tuberculosis is transmitted from person to person through the air (airborne)
• Hepatitis B virus (HBV) can be transmitted from mother to child at birth (perinatal transmission) or through exposure to infected blood or body fluids
• Dengue virus (DENV) is transmitted through mosquitoes, specifically the female Aedes aegypti
• Noncommunicable diseases are not transmitted by another person, a vector, or the environment
• Risk factors for noncommunicable diseases include controllable factors and uncontrollable factors such as age, gender, ethnicity, and heredity
• Common lifestyle diseases include cardiovascular disease, cancer, and diabetes
• Cardiovascular disease affects the heart or blood vessels and includes types like hypertension, atherosclerosis, and diseases of the heart
• Hypertension is a major risk factor for other types of cardiovascular diseases and is more common among people over the age of 35
• Normal blood pressure ranges are:

  • Less than 120 mmHg systolic and 80 mmHg diastolic for normal
  • From 120/80 mmHg to 129/80 mmHg for prehypertension
  • From 130/80 mmHg to 139/89 mmHg for stage 1 hypertension
  • 140/90 mmHg or higher for stage 2 hypertension
• Atherosclerosis results from the deposition of material in the walls of arteries, forming plaques composed of a fatlike substance containing cholesterol
• Factors influencing the development of atherosclerosis include lack of exercise, smoking, obesity, and a high-fat and cholesterol diet
• Diseases of the heart within cardiovascular disease include heart attack, arrhythmias, and heart failure
• A heart attack occurs when a thrombus suddenly blocks a coronary blood vessel, leading to reduced blood supply, tissue death, and potential heart failure
• Arrhythmias are irregular heartbeats and can include abnormal heart rhythms, heart blocks, and premature contractions
• Heart failure usually results from progressive weakening of the heart muscle, leading to the heart not pumping enough blood and blood backing up in the veins
• Cancer is caused by uncontrolled cell growth and can spread to neighboring tissues and other parts of the body (metastasis)
• Risk factors for cancer include exposure to carcinogens like cigarette smoke and ultraviolet light, as well as lifestyle behaviors
• Types of cancer include lymphomas, leukemias, carcinomas, and sarcomas
• Diabetes Mellitus is a chronic disease affecting how body cells convert food into energy, with types including Type I, Type II, and Gestational diabetes
• Communicable diseases can be spread from one person to another or to the environment by agents like fungi, bacteria, viruses, protozoans, or rickettsia
• Prevention methods for communicable diseases include sanitation techniques, handwashing, vaccination, boosting the immune system, and physical and chemical barriers of the body
• Noncommunicable diseases cannot be spread and are influenced by lifestyle, behavior, genetic makeup, and other factors
• Prevention methods for noncommunicable diseases include maintaining a healthy lifestyle, eating a balanced diet, engaging in physical activity, and reducing risk factors