• Like
Ch14 diseases
Upcoming SlideShare
Loading in...5
×
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Be the first to comment
    Be the first to like this
No Downloads

Views

Total Views
563
On Slideshare
0
From Embeds
0
Number of Embeds
1

Actions

Shares
Downloads
21
Comments
0
Likes
0

Embeds 0

No embeds

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
    No notes for slide

Transcript

  • 1. Chapter 14
 Infection, Immunity, and Noninfectious Disease
  • 2. Noninfectious Disease • Diseases are processes that affect proper body functioning. • Infectious diseases are caused by pathogens, such as bacteria, rickettsias, viruses, fungi, and parasitic worms. • For example, colds, influenza, and sexually transmitted infections • Noninfectious diseases are caused by genetic abnormalities, interactions between heredity and environmental factors, or environment alone. • For example, cystic fibrosis, asthma, and lead poisoning
  • 3. Noninfectious Disease Genetic Diseases • Two types – Inherited diseases – Diseases cause by errors when egg or sperm (gametes) form • Inherited diseases are transmitted only by gene transfer from parents to offspring. – These diseases are caused by disorders of genes, defects arise through mutations – Cystic fibrosis, muscular dystrophy, Sickle Cell Disease, Down syndrome
  • 4. Noninfectious Disease Genetic Diseases • Diseases Caused by Errors in Sex Cell Division – Down Syndrome • Affects approx. 1 in 700 to 800 newborns. • A child with Down syndrome has three instead of the normal two chromosomes on chromosome #21. • Risk of having a baby with Down syndrome increases dramatically in women who are over 30 years of age.
  • 5. Noninfectious Disease Genetic Diseases • Diseases Caused by Errors in Sex Cell Division – Down Syndrome • Mental retardation • Developmental delays • Physical defects –Stocky build –Short hands –Flattened facial features
  • 6. Noninfectious Disease • Conditions caused by interaction of genes and environment include: – Asthma – Ulcers – Diabetes mellitus – Migraine headaches – Cardiovascular disease – Cancer
  • 7. Trends in Infectious Disease • The primary causes of death in the United States have shifted from infectious diseases in 1900 to noninfectious diseases today. • In 2007, influenza and pneumonia were the only infectious diseases among the top fifteen killers of Americans. • Worldwide, however, infectious diseases are the leading causes of death. Additionally, many bacteria once easily killed with antibiotics are resistant to the variety of antibiotics available at this time. No more spraying= malaria
  • 8. The Chain of Infection • Infection results from the interaction between a pathogen (the agent of infection) and a host (the organism that supports the growth of the pathogen). – The link between the pathogen and the host is transmission, the route by which the pathogen gets to the host. – Pathogen – Transmission – Host
  • 9. The Chain of Infection The First Link: Pathogen – Severity of an infectious disease depends on: • Type of pathogen • Virulence of pathogen • Pathogen’s ability to multiply and spread within body • Pathogen’s ability to combat the body’s defenses • The body’s reaction to the pathogen
  • 10. The Chain of Infection The First Link: Pathogen – Bacteria • Bacteria are microscopic, unicellular organisms with a simple cell structure. • Bacteria cause infections such as strep throat, certain types of food poisoning, and infected skin wounds. • When bacteria enter the body, they adhere to host’s cells and grow and multiply there. –Some produce toxic chemicals
  • 11. The Chain of Infection The First Link: Pathogen – Bacteria • Rickettsias –Bacteria-like organisms that live within host cells. –Cause infectious diseases such as: »Typhus »Rocky Mountain Spotted Fever
  • 12. The Chain of Infection The First Link: Pathogen – Viruses • do not have a cellular structure like living organisms, instead they are hereditary material with a protein coat. • Cause diseases such as cold, influenza, mumps, measles, chicken pox, hepatitis, and AIDS. • Adhere to host cells and use those cells to produce new viruses.
  • 13. The Chain of Infection The First Link: Pathogen – Viruses • When the newly formed viruses break out of a cell, the cell dies. –The death of cells cause many of the signs and symptoms associated with viral diseases.
  • 14. The Chain of Infection The First Link: Pathogen – Viruses • Certain types of viruses invade cells but do not produce new viruses immediately (latent state). –Latency may cause changes in host cell that result in cancer. • Latent viral hereditary material can become reactivated and replicate repeatedly. –It can result in bouts of viral disease.
  • 15. The Chain of Infection The First Link: Pathogen – Fungi • More commonly called molds and yeasts. • Cannot produce their own food and must grow on various organisms to survive. • Healthy humans have a high degree of resistance against fungi. –Fungi cause opportunistic diseases such as athlete’s foot and yeast infections when the body’s resistance has weakened.
  • 16. The Chain of Infection The First Link: Pathogen – Other Types of Pathogens • Protozoans –Single-celled organisms. –Cause diseases such as malaria, trichomonas urogenital (“trich”) infections.
  • 17. The Chain of Infection The First Link: Pathogen – Other Types of Pathogens • Parasitic Worms –Include certain roundworms, flatworms, and flukes. –Not prevalent in the United States. • Arthropods –Occasionally fleas, tics, mites, lice and mosquitoes can transmit pathogens to humans
  • 18. The Chain of Infection The Second Link: Transmission – Communicable diseases are infectious diseases that spread from person to person. – Noncommunicable diseases are not spread from person to person.
  • 19. The Chain of Infection The Second Link: Transmission – Noncommunicable Diseases • Infections can be caused by: –Growth of bacteria that normally inhabit the body –Staphylococcus bacteria normally live on skin but can cause disease. • Ingestion of toxins or poisons produced by some bacteria –Staphylococcus can grow in food and produce a toxin that sickens people who eat the food.
  • 20. The Chain of Infection The Second Link: Transmission – Noncommunicable Diseases • Infection with pathogens from environmental or animal sources –Legionnaire’s disease is contracted by contact with an environmental source. –Lyme disease is contracted from an animal source »Mice and deer are infected with a type of bacteria that causes Lyme disease. »The tick that bites mice and deer can transmit the bacteria from these animals to humans.
  • 21. The Chain of Infection The Second Link: Transmission – Communicable Diseases • Transmitted from person to person: –By direct or indirect contact –By a common vehicle (food, water, a common drinking glass) –Through the air –By vectors (organisms other than humans, such as mosquitoes)
  • 22. The Chain of Infection The Third Link: The Host – Stress can reduce a person’s resistance to infection. – High-intensity or exhaustive exercise can suppress the immune system. – Race and age affect resistance or susceptibility to disease. – Presence of other diseases can weaken the body’s defense mechanisms.
  • 23. Immunity Immunity is protection from disease. • The two types of immunity are – Nonspecific – Specific.
  • 24. Immunity Nonspecific Immunity – Comprises a variety of defense mechanisms that combat any type of damage to the body, including the invasion of infectious agents. – Pathogens can enter the body at sites called portals of entry. – Mechanical and Chemical Barriers.
  • 25. Immunity Nonspecific Immunity – Comprises a variety of defense mechanisms that combat any type of damage to the body, including the invasion of infectious agents. – Pathogens can enter the body at sites called portals of entry.
  • 26. Immunity Nonspecific Immunity – The Skin and Mucous Membranes • Intact skin: mechanical barrier • Mucus: keeps membranes moist and traps foreign particles and organisms • Cilia: in upper respiratory tract move mucus to the back of the mouth, to be swallowed • Tears: chemical defense • Lysozyme: found in saliva. • Stomach acid: can kill most of the microorganisms that are in food.
  • 27. Immunity Nonspecific Immunity – White Blood Cells and Phagocytosis • White blood cells (leukocytes) ingest foreign cells and debris in process called phagocytosis. • Neutrophils and macrophages are leukocytes that protect the body through phagocytosis. • Lymphocytes are another type of leukocyte.
  • 28. Immunity Nonspecific Immunity – Lymphatic System • Composed of vessels and nodes through which tissue fluid (lymph) flows –Lymphocytes –Tonsils –Spleen –Thymus • Removes microorganisms and other foreign substances from tissue fluid
  • 29. Immunity Nonspecific Immunity – Inflammation • Inflammation is a series of responses that occur when the body is harmed by occurrences such as bacterial or viral invasion (infection), cuts, chemical damage, and burns. • The response can be local (affecting the immediate area that is harmed) or systemic (affecting the entire body).
  • 30. Immunity Nonspecific Immunity – Natural killer cells • specialized white blood cells that attack cancer cells and body cells infected with viruses.
  • 31. Immunity Nonspecific Immunity – Interferons • Proteins released from cells that are infected with a virus. • Stimulates uninfected cells to produce a protein that breaks down hereditary material of virus. • Damaged viruses cannot infect cells and make copies of themselves. –As a result, the infection is halted.
  • 32. Immunity Specific Immunity – A function of the immune system. – Made up of cells residing in tissues scattered throughout the body. These cells are able to react to specific pathogens and foreign molecules.
  • 33. Immunity Specific Immunity – Antigens: The Triggers of Specific Immunity • Antigens are usually foreign, or “nonself,” proteins. • Antigens also can be noninfectious agents such as pollens or tissue transplants. • Sometimes, the body perceives its own cells as foreign and begins attacking and destroying them, causing autoimmune diseases such as rheumatoid arthritis.
  • 34. Immunity Specific Immunity • Specific immunity is a function of the immune system. There are two kinds: – Antibody-Mediated Immunity • Responds to extracellular antigens –Bacteria and the toxins they produce • Antibodies interact in lock-and-key fashion with antigens –This binding stimulates the inflammatory response and phagocytosis –Specialized white blood cells, B lymphocytes (B cells), are involved
  • 35. Immunity Specific Immunity • Specific immunity is a function of the immune system. There are two kinds: – Cell-Mediated Immunity • Reacts to intracellular antigens –Viruses, fungi, few types of bacteria, and parasites • Also reacts against foreign tissue transplants and controls tumor cell growth
  • 36. Immunity Specific Immunity • Specific immunity is a function of the immune system. There are two kinds: – Cell-Mediated Immunity • Cells involved: –Cytotoxic T cells - destroy invading intracellular pathogens by secreting chemicals that break apart infected host cells. –Helper T cells - secrete chemicals that enhance the activity of cytotoxic
  • 37. Immunity Specific Immunity • Specific immunity is a function of the immune system. There are two kinds: – Cell-Mediated Immunity • Cells involved: –Suppressor T cells: shut down the immune system. –Memory T cells: act like memory B cells, responding rapidly and forcefully to future encounters with the same antigens that elicited the response.
  • 38. Immunity Interactions between Specific and Nonspecific Immunity • The specific and nonspecific mechanisms of the immune system work together to prevent infection or combat infection once it occurs
  • 39. Protection Against Infectious Diseases • Inborn immunity is inherited. • Acquired immunity is not inherited, but develops over a lifetime. • Active acquired immunity is an immune system response developed as a result of contact with a pathogen, which includes development of memory B cells or T cells. Vaccination • Passive acquired immunity is conferred when a person is given antibodies. Passive immunity can be acquired naturally when antibodies from a mother cross the placenta and enter the bloodstream of a developing fetus.
  • 40. Drugs That Combat Infection • Getting rest and drinking sufficient fluids are usually recommended. • Antibiotics kill bacteria or inhibit their growth; do nothing to combat viral infections, their misuse may result in producing antibiotic-resistant bacteria. • Antifungal drugs are available to treat fungal infections; other medications have been developed to treat parasites and protozoans. • Antiviral drug development has been slow because viruses reside inside cells. An effective drug must kill the virus without harming its host.
  • 41. Sexually Transmitted Infections • STIs are spread from person-to-person by intimate contact that occurs during sexual activity, primarily sexual intercourse. – In general, the pathogens that cause STIs pass from infected sores, secretions, or tissues of an infected person’s reproductive tract. – Contracting an STI is more likely when other STIs are present. • Most STIs are caused by viruses and bacteria. – Some are caused by yeast, protozoans, mites, and lice.
  • 42. Sexually Transmitted Infections Caused by Viruses • Extremely serious because they cannot be cured. • Three sexually transmitted viruses have been implicated in the development of certain cancers: HIV, HPV, and HBV (hepatitis B).
  • 43. Sexually Transmitted Infections Caused by Viruses Human Immunodeficiency Virus (HIV) – HIV infection progresses to AIDS. – In the United States, the AIDS epidemic primarily affects men who have sex with men. – Globally, approximately 33.2 million people are living with HIV.
  • 44. Sexually Transmitted Infections Caused by Viruses Human Immunodeficiency Virus (HIV) • The Progression of the Disease: HIV Infection and AIDS – Being infected with HIV does not mean a person has AIDS. It progresses to AIDS. – Approximately 1 to 3 weeks after infection with HIV, most people experience flu-like symptoms that last 1 to 2 weeks. • Fever, sore throat, headache, rash, and general weakness and discomfort. – Further symptoms may not develop for 8 to 10 years (asymptomatic phase).
  • 45. Sexually Transmitted Infections Caused by Viruses Human Immunodeficiency Virus (HIV) • The Progression of the Disease: HIV Infection and AIDS – The symptomatic phase of HIV disease usually begins when the helper T cell numbers have declined to about 500 cells or fewer per cubic millimeter of blood (500 cells/mm3). Normal helper T cell numbers are about 800 to 1200 cells/mm3. – Symptomatic phase of HIV infection may begin with fever, night sweats, headache, fatigue, and diarrhea.
  • 46. Sexually Transmitted Infections Caused by Viruses Human Immunodeficiency Virus (HIV) • The Progression of the Disease: HIV Infection and AIDS – A person is usually diagnosed with AIDS when his or her T cell count drops to 200 cells/mm3, and he or she develops certain opportunistic infections such as pneumonia, toxoplasmosis, Kaposi’s sarcoma, and cytomegalovirus retinitis may develop. – Wasting syndrome – Patients live an average of 2 years after being diagnosed with AIDS.
  • 47. Sexually Transmitted Infections Caused by Viruses Human Immunodeficiency Virus (HIV) • How is HIV Transmitted – Sexual contact with infected person – Direct contact with blood, semen, vaginal secretions – Tears in skin and mucous membranes make it easier for virus to enter body – ANY sexual behavior that results in contact with infected blood, semen, or vaginal secretions is risky.
  • 48. Sexually Transmitted Infections Caused by Viruses Human Immunodeficiency Virus (HIV) • How is HIV Transmitted – Exposure to infected blood or blood products: • Sharing of contaminated needles and syringes by injecting drug abusers • Blood transfusions –There is no risk to donate blood. – Transfer via placenta during fetal development and during the labor process – Breastfeeding
  • 49. Sexually Transmitted Infections Caused by Viruses Human Immunodeficiency Virus (HIV) • How HIV is NOT Transmitted – Casual contact with infected people – Sharing things such as telephones, combs, and eating utensils or using drinking fountains – Kissing does not appear to transmit HIV – Mosquitoes do not transmit HIV
  • 50. Sexually Transmitted Infections Caused by Viruses Human Immunodeficiency Virus (HIV) • Treatment of HIV Infection – There is no cure for HIV infection and AIDS. – No effective vaccine has been produced. – Approved anti-HIV drugs interfere with viral copying, but the virus mutates quickly and these drugs soon become ineffective. • A combination of drugs is used and appears to work best to retard HIV. • Highly active antiretroviral therapy (HAART) seems effective, but has side effects. • HAART includes new fusion inhibitor drugs.
  • 51. Sexually Transmitted Infections Caused by Viruses Genital Herpes – HSV-1 causes cold sores around the lips – HSV-2 causes sores on genital and anal areas. • Each viral type can infect both oral and genital areas. – After initial infection, incubation period lasts about a week. – Signs and symptoms • Skin lesions that become filled with fluid that contains the virus and will eventually open • Headache, fever, weakness, and muscle pain
  • 52. Sexually Transmitted Infections Caused by Viruses Genital Herpes – Recurrences usually occur 5 to 8 times per year. • Stress, lack of sleep, and menstruation often trigger recurrences. – A person without symptoms may shed herpes viral particles, infecting others. – Treatment with acyclovir reduces recurrence rate. – Herpes virus can infect newborns during delivery and cause serious damage to the infant’s nervous system or even cause death.
  • 53. Sexually Transmitted Infections Caused by Viruses Genital Warts – Human papillomavirus (HPV) causes warts. – Genital warts are not painful, but some types are associated with cervical cancer. – Incidence of genital warts has been rising. – Treatments include medications, freezing, cauterizing, lasers, and anti-viral injections. – In 2006, the FDA approved a vaccine that protects against four major types of HPV. • The vaccine is recommended for adolescent girls who have not yet had sex.
  • 54. Sexually Transmitted Infections Caused by Bacteria STIs caused by bacteria can be cured. If not treated, not treated promptly, or not treated properly, bacterial STIs can damage the reproductive system, possibly causing infertility. • Syphilis • Gonorrhea • Chlamydial Infections
  • 55. Sexually Transmitted Infections Caused by Bacteria Syphilis – Syphilis is caused by a bacterium, T. pallidum. – Incidences of syphilis increased between 2001 and 2006 primarily among men who have sex with men. – After T. pallidum enters the body, the incubation period lasts about 3 weeks. – Syphilis has three stages. – Syphilis can damage the brain, heart, and blood vessels, resulting in paralysis and death. – Penicillin kills T. pallidum.
  • 56. Sexually Transmitted Infections Caused by Bacteria Syphilis – Primary - development of a chancre – Secondary - After the chancre heals, the signs and symptoms of secondary syphilis occur. • These usually include sore throat, weakness, muscle pain, weight loss, fever, headache, and a rash that covers the body. – Tertiary stage: tissue-destroying lesions called gummas develop. Gummas not only affect the skin but can destroy any type of tissue in the body—even bones.
  • 57. Sexually Transmitted Infections Caused by Bacteria Gonorrhea – Gonorrhea is caused by the bacterium Neisseria gonorrhoeae. – In 2009, the age group with the highest prevalence of gonorrhea infection was young men and women aged 15 to 29 years. – The incubation period is 2 to 8 days. – It is the most common cause of Pelvic Inflammatory Disease (PID) in women. – Gonorrhea is treated with antibiotics. – It may cause blindness in newborns.
  • 58. Sexually Transmitted Infections Caused by Bacteria Chlamydial Infections – One of the most prevalent STIs in the U.S. – Caused by the bacterium Chlamydia trachomatis – Mild symptoms in men • Painful urination and whitish or clear discharge from urethra • The bacteria may travel to other parts of the male reproductive tract and cause inflammation of epidiymides
  • 59. Sexually Transmitted Infections Caused by Bacteria Chlamydial Infections – Produces no symptoms in 70% of women • PID is most serious complication • Can infect newborn during birth process and cause eye and lung damage – Treated with antibiotics
  • 60. Other Sexually Transmitted Infections Trichomonas vaginalis Infections (Trichomoniasis) – Protozoan infection – Women are 20 times more likely to contract “trich” infections than men. – Organism lives in glucose-rich vaginal surface tissues. • Normal acid environment of vagina and male urethra inhibits the growth of T. vaginalis. • If vagina becomes less acid, the protozoan can grow there. • Infection almost always contracted by having sex with infected person.
  • 61. Other Sexually Transmitted Infections Trichomonas vaginalis Infections (Trichomoniasis) – Signs and symptoms • In women, abnormal, bad-smelling discharge that may be thin and foamy –Itching, burning, swelling, redness, and tenderness of vulva • In men, painful urination and urgency to urinate – Men become infected, but infection usually subsides without treatment.
  • 62. Other Sexually Transmitted Infections Yeast Infections – Candidiasis • Acquired through intercourse with infected person • Develops in women who are taking antibiotics or during pregnancy • Often affects women with poorly controlled diabetes or other STIs – Signs and symptoms • Soreness, burning, irritation, swelling, and a white vaginal discharge that looks like “cottage cheese”
  • 63. Other Sexually Transmitted Infections Pubic Lice – Infestation of lice in pubic area is commonly called “having crabs.” • Spread primarily by sexual contact. • Sucks the blood of their host; females lay eggs in pubic hair. • Causes itching, swelling, redness, and irritation. • OTC and prescription medications are available.
  • 64. Other Sexually Transmitted Infections Scabies – Scabies (“itch mites”) burrow into the skin, making thin, red lines, or bumps in the skin. • Scabies lay eggs in skin. • Can be spread through sexual intercourse and also through bed linens, towels, pillows, or other household items. • Treatment is with prescription medications.
  • 65. Protecting Yourself Against STI’s • Anyone who is sexually active can contract an STI • The most effective strategies are to abstain from sexual activity and drug use. • Limiting the number of sex partners reduces risk. • Never share needles and syringes if you are injecting drugs and never have sex while under the influence of drugs or alcohol. • Always using latex condoms during sexual activity also reduces risk.
  • 66. Across the Life Span • Noninfectious diseases and conditions present at birth are termed birth defects. • Some birth defects are caused by environmental influences. – Teratogens, substances such as alcohol, can enter the fetus and cause birth defects. • Some birth defects are inherited. – Metabolic diseases (i.e., Tay-Sachs disease)
  • 67. Across the Life Span • Most genetic diseases strike early in life. – Huntington’s chorea does not appear until age 40. – Alzheimer’s has a strong genetic link. • Many childhood infections are no longer common due to routine vaccination of children. • Sexually active adolescents and young adults are at highest risk for contracting STIs due to unprotected sex. • Infections are a major cause of illness and death among the elderly.