PHARMACY TECHNICIAN CHAPTER TWENTY SEVEN

Nonspecific Defenses Considered a “first line of defense” against disease and infection Nonspecific defense mechanisms include: Physical barriers (unbroken skin) Natural deterrents (fluids and immune cells that attack invaders) Inflammatory process 2

Specific Defenses Specific defense mechanisms are called the immune system Immune system has specialized molecules and cells that fight foreign invaders Immune system molecules consist of two types of protein molecules: Antibodies—identify foreign particles Complement—destroys foreign particles 3

Parasites Multicellular organisms or single-celled organisms that are not bacteria or fungi Asymmetrical symbiotic relationship: Parasite benefits from host Host receives no benefit from or is harmed by relationship Most common parasites in the United States are: Pinworms Roundworms Tapeworms Transmission usually occurs via ingestion of contaminated food or soil 4

Bacteria and Virus Bacteria Virus Unicellular, prokaryotic microorganisms May be round (coccus/cocci), rod (bacillus/bacilli), or spiral-shaped May cause disease; may also have beneficial relationships (E. coli, etc.) Virus Ultramicroscopic infectious pathogen Can replicate itself only within cells of a living host Uses the DNA and RNA of the host Antibiotics are ineffective against viruses 5

HIV (Human Immunodeficiency Virus) Can be categorized as either HIV-1 or HIV-2 Most references to HIV refer to HIV-1, the most common worldwide Both types are transmitted: By sexual contact Through bodily fluids At birth from mother to child Both types of HIV cause clinically indistinguishable AIDS Acquired immune deficiency syndrome Immune system becomes severely suppressed Body cannot fight opportunistic infections or cancers 6

Five Stages of HIV Progression to AIDS Stage 1—initial transmission and infection with HIV Stage 2—infected without presentation of signs or symptoms (10 or more years) Stage 3—signs and symptoms of HIV begin to appear Stage 4—AIDS opportunistic infections lead to a CD4 cell count or level below 200 per cubic millimeter of blood Stage 5—last and final stage of wasting to death 7

Classes of HIV Drugs Vaccine Not yet developed Would enable immune system to destroy HIV before infection occurs Attachment inhibitors Would prevent HIV from attaching to host cells Inhibitors Block the synthesis of copies of the viral RNA Virus cannot duplicate itself 8

Autoimmune Disease Occurs when immune system mistakenly attacks the cells, tissues, and organs of its own body Immune system cells and molecules accumulate at a target site This gathering is broadly referred to as inflammation Autoimmune diseases are not contagious and are not related to AIDS or cancer 9

Drug Resistance Defined as a microorganism’s ability to live and grow in the presence of an anti-infective or antimicrobial drug Is a result of genetic mutation during cell division Allows the pathogen to evade or avoid the destructive mechanism of a drug Bacteria are especially prone to develop drug resistance The increasing use of antibiotics contributes to this action and is called antibiotic resistance 10

Preventing Antibiotic Resistance Avoid unnecessary antibiotic use in humans Avoid unnecessary antibiotic use in animals Use most specific antibiotic possible Complete an antibiotic regimen (no leftover pills) There may be no ultimate cure for antibiotic resistance However, development of resistance can be slowed down 11

Anti-Infectives Umbrella name under which various types of drugs are then subclassified Also called antimicrobial—against the growth of a microorganism or microbe Antibacterials—treat bacteria only Antivirals—treat viruses only Antifungals—treat fungi only Metronidazole—amoebicidal, bactericidal, and trichomonacidal 12

Tuberculosis Caused by Mycobacterium tuberculosis bacterium May attack any part of the body, but usually attacks the lungs Spread by breathing air into which infected people have coughed or sneezed Drug of choice for treatment is isoniazid (INH) Taken for at least six to nine months Longer if the patient has a weakened immune system 13

Malaria Transmitted by parasites found in malaria-infected mosquitoes Can be cured with prescription drugs Type of drug used and duration of treatment depend on: Which type of malaria is diagnosed Where the patient was infected Age of the patient Orogression of the disease at the start of treatment 14