Antimicrobial and Antiviral Agents

Antimicrobial Agents

• Substances that kill or inhibit microorganisms like bacteria, fungi, and viruses
• Used as disinfectants, antiseptics, and antibiotics

Antibiotics/Antibacterial

• Effective against bacteria
• Treats bacterial pneumonia

Antivirals

• Effective against viruses like herpes and HIV
• Medicine to treat viral infections
• Reduces the risk of spreading viruses
• Shortens the duration of illness and reduces the risk of severe illness
• Prevents viruses from replicating
• Blocks viruses from entering host cells
• Boosts the immune system
• Lowers the viral load in the body
• Most target specific viruses but Broad-spectrum antivirals are effective against a wide range of viruses
• Taken orally, as eye drops, inhalers, injections, IV infusions, or topical ointments
• Side effects: headache, dizziness, fatigue, nausea, diarrhea, skin rash, and muscle or joint pain
• Paxlovid (nirmatrelvir/ritonavir) treats COVID-19 and take as prescribed, even with side effects
• Begin taking when symptoms start and consult a healthcare provider if at increased risk

Anti Parasitic Agents

• Effective against parasites
• Treats malaria.

Antifungals

• Effective against fungi
• Treats yeast infections
• Disrupts fungal cell membranes or cell walls
• Action: kill or stop the growth of fungi
• Disrupts fungal cell components
• Inhibits fungal membrane and cell wall synthesis
• Alters fungal membranes and affects microtubules and nucleic acid synthesis
• Examples: ringworm, Tinea facialis, Tinea pedis, Tinea scalp, Tinea manus, and Tinea manus dorsum
• Topical antifungal forms: creams, ointments, shampoo, or powder
• Oral antifungal forms: pills or liquids
• Can be administered intravenously (IV)
• Creams & Ointments: Applied to the skin to treat fungal infections
• Gels: Applied to the mouth to treat thrush
• Sprays: Applied to the skin to treat fungal infections
• Pills & Liquids: Taken orally to treat fungal infections
• Liquids: Taken orally to treat fungal infections
• Suppositories: Used vaginally to treat fungal infections
• Injections: Given intravenously or as a shot to treat severe fungal infections

Antiparasitics

• Treats infections caused by parasitic organisms and interfere with the parasite's metabolism or nervous system
• Ivermectin: Targets the parasite's nervous and muscular systems, causing paralysis
• Albendazole: Disrupts the parasite's metabolism and energy production
• Benzimidazoles: Disturb the parasite's energy metabolism and microtubule polymerization
• Levamisole: Causes reversible spastic paralysis of the worm
• Praziquantel: Damages the worm's tegument and increases muscle activity
• Paromomycin: Inhibits protein synthesis by binding to the 165 ribosomal RNA subunit
• Toltrazuril: Active against several genera of the Apicomplexa

Natural Antibiotics

• Produced by microorganisms like bacteria and fungi as part of their immune system
• Examples: Garlic, Goldenseal, Clove oil, Oregano, Echinacea, Ginger, Manuka honey, Myrrh, Thyme essential oil, Chili peppers, Tea tree oil, Turmeric, Apple cider vinegar

Immunology

• Study of the body's defense system, called the immune system to protects the body from infections, foreign substances, and other threats.

Immunogen

• A substance that stimulates the immune system to produce antibodies or a cell-mediated response and a type of antigen
• Not all antigens are immunogens

Antigen

• A substance that triggers the body's immune system to produce antibodies
• Found in the environment, in the body, or on cells such as toxins, chemicals, bacteria, viruses, pollen, and cancer cells
• Serve as markers indicating harmful elements in the body
• Used in laboratory tests for identifying tissues or cells
• Used in antigen testing to diagnose viral infections, monitor conditions, and match donors for transplants
• Blood group antigens are surface markers on red blood cells and determine a person's blood type

Epitope

• A small part of a molecule that triggers an immune response, also known as an antigenic determinant
• Composed of amino acids or other chemical groups
• Found on the surface of molecules (often proteins)
• Binds to specific receptors on B and T lymphocytes
• Binding stimulates an immune response Importance:
• Are important for vaccine development, illness prevention, and therapy
• Epitope mapping can help identify and characterize antibody binding sites
• Can help develop new therapeutics, vaccines, and diagnostics
• Can be linear or conformational dependent on the arrangement of amino acids in the protein

Hapten

• A small molecule that can trigger an immune response when attached to a larger carrier molecule
• Haptens are found in many common substances, including drugs, hormones, and dyes.

Innate Immunity

• The body's first line of defense against foreign substances such as viruses and bacteria and present at birth
• Does not require prior training
• Works through barriers like the skin, mucous membranes, tears, and stomach acid to prevent harmful substances
• White blood cells (monocytes, neutrophils, eosinophils, and mast cells) respond to foreign invaders
• Cytokines, lymphokines, and chemokines are secreted to limit tissue injury and prevent the spread of viruses
• Response time: Within hours of exposure
• Specificity: Non-specific to
• Cells Involved: Macrophages, neutrophils, eosinophils, basophils, mast cells, dendritic cells
• Examples: Cough reflex, skin, stomach acid, tears, mucus

Adaptive Immunity

• The ability of the immune system to recognize and respond to specific foreign substances involving B cells, T cells, and antibodies
• Response time: Days after exposure
• Specificity: Specific to anti-
• Cells Involved: B cells, T cells, antibodies
• Examples: Creates immunological memory

Immune Response

• How the body defends itself against harmful substances like bacteria and viruses and involves a series of steps including inflammation, fever, and the production of antibodies
• The immune system identifies antigens, which are usually proteins, on the surface of harmful substances
• Action: attack and destroy harmful substances and produce antibodies

Symptoms of Immune System issues

• Fatigue, fever, joint pain, rashes, frequent colds or flu, hair loss, skin issues (itchy skin, dry eyes, white patches, yellowing skin)
• Swelling around the joints, tiredness, unexplained weight loss/gain, headaches, muscle aches, night sweats, trouble concentrating, or swollen lymph nodes
• Can be due to an overactive, underactive, or faulty immune response
• Examples of immune system disorders: Eczema, psoriasis, psoriatic arthritis, rheumatoid arthritis (RA), and lupus

Primary Immune Response

• The first time your body encounters a foreign antigen
• IgM is the main antibody produced
• Takes several days to develop

Secondary Response

• Occurs after subsequent exposures to an antigen
• IgG is the main antibody produced
• Develops more rapidly than the primary response, is stronger, and lasts longer

Humoral Immunity

• A defense mechanism using antibodies produced by B lymphocytes
• Pathogen entry activates B lymphocytes, which mature into plasma cells
• The plasma cells secrete antibodies, neutralizing or eliminating the pathogen

Antibodies

• Also known as immunoglobulins
• Proteins that help the body fight infections by identifying and neutralizing harmful substances
• Produced by plasma cells
• Binds to antigens to cause an immune response
• Directly destroys antigens or makes it easier for white blood cells to do so
• Structure: Y-shaped proteins made of four polypeptide chains (two identical heavy and two identical light chains held together by disulfide and noncovalent bonds)
• Heavy chains have ≈ 440 amino acids and light chains have ≈ 220 amino acids
• Tips of Y have different amino acid sequences for specific antibody types that give each unique shape
• The folds of repeated segments of ≈ 110 amino acids is called domains
• Domains are grouped into Fab and Fc regions to binds to antigens
• Five main types: IgG, IgM, IgA, IgE, and IgD, each defending the body against a specific antigen

Cell-Mediated Immunity

• An immune response using the body’s cells to target and destroy infected cells
• Also known as cellular immunity
• Cells in the body become infected by a virus, bacterium, or fungus
• T lymphocytes detect the infection with help of MHC class I proteins
• Helper T cells release cytokines
• Cytokines cause killer T lymphocytes and macrophages to go to infected cell
• The killer T lymphocytes and macrophages eliminate the infected cell
• Regulatory T cells end and suppresses T cells that mistakenly react against self antigens
• Examples: contact dermatitis and Tuberculin skin test Importance: Is important in many illnesses and related to diagnostics of infectious diseases

Complement System

• A group of proteins help the body's immune system to fight infection and considered part if not the first line of defense for the body
• Action: recognizes, eliminates pathogens, helps phagocytic cells recognize and kill pathogens, promote inflammation, attack the cell membrane of pathogens and helps body heal

Hypersensitivity Type I

• "Type one immediate hypersensitivity": Rapid immune response triggered by IgE antibodies to allergens, histamine released and leads to inflammation
• Symptoms include Hives, swelling and breathing difficulties in minutes after allergen with fast rate of reaction
• Mechanism: causing mast cells to degranulate and release histamine and other chemicals
• Common Allergens Pollen, dust mites, pet dander, food, insects, medication and anaphylaxis reactions

Hypersensitivity Type II

• Antibodies bind to antigens on cells/tissues and damage cells or inhibit their function
• Antibody involvement: Primarily mediated by IgG or IgM antibodies
• Complement activation: Antibodies bind to cell surfaces, triggering complement
• Cytotoxicity: Natural killer cells recognize and destroy antibodies
• Examples: Goodpasture syndrome, Myasthenia gravis and Graves' disease

Hypersensitivity Type III

• Immune system overreacts, forms antibody-antigen complexes, and leads to inflammation/tissue damage
• Serum sickness: Occurs after foreign serum produces antibodies Examples: Kid-Post-streptococcal and Systemic lupus erythematosus

Type 4T Cell Mediated Hypersensitivity and Vaccines

• Delayed type reaction where response is driven by T lymphocytes, inflammation and causes and tissue damage after exposure

Vaccines

• Suspension of weakened, killed, or other microorganisms to help prevent diseases
• In making: first generate the antigen, isolate, then purify an enhance to ensure stability and shelf life and produced on large quantities
• Delivery: packaged and administered to the human body through liposomes, emulsions, and micro-particles

Action and Immunization Imitate infection, produce antibodies against infectious and recognizes infectious

Vaccines and Immunization Examples

• Active vs Passive: Depends on the body, exposure of a pathogen triggers

Live attenuated The yellow fever vaccine is a use a virus that is weakened

Toxoid The toxoid vaccine is uses bacterial to stimulate

Killed The BCG vaccine is a use a virus or bacteria proteins

Microbial and Disease Causes

• Contaminated food, objects, surfaces, etc.: Can cause serious bacterial, fungal, and viral diseases
• Disease: Bacteria, Viral, Fungal and Parasitic

Bacteria

• Caused by single organisms and can be contracted by, contaminated surfaces
• Direct/ Indirect contamination
• Bacteria Illness causes- skin infection, strep, TB

Fungal

• Fungal illness causes- from spores and infection athlete’s feet or ringworm

Virus

• Virus infection- Common cold or flu, fevers, etc. (Respiratory, HIV And AIDs) Cysts formation

Transmission

Occurs in contaminated water, air and skin contact Symbiosis- A relationship between two or more species Contamination caused by sterile or unclean areas Pathogenicity- ability to cause microorganism/ disease to take over

Bacteremia, Pyemia, Viremia and Toxemia

• Bacteremia: Stream infection in the blood. Can be transferred by medical devices
• Pyemia- blood is poisoned by the spreading of pus Viremia- viruses are released in blood stream
• The symptoms include a fever and a medical condition to the body. Is the result after pregnancy

Infection and Postulates

• Infection that multiple and causes disease
• Postulates used to determine microorganism; must be present, isolate, then reidentified again

Protozoa and History

Francesco Redi (1626-1697), an Italian physician, is known as the "father" of parasitology.

Parasitology study of parasites living on relationships that include biochemistry and immunology

Parasites are classified

Amoeba , tissue multiuse cellular that are found various locations , as well host response, but human can be infected

Obligate Infection, free flowing, parasitic

Immune response and pathogenesis

• Pathogenesis: is A process of development and infection in cell ( bacteria, etc)
• Direct and indirect contamination

Injuries is referred to physical damage of causes of pathogens Infections and autoimmune system cause by pathogens and too actively