Infectious & Communicable Diseases Chemeketa Community College
Are we at risk? • Patient contact • Co-workers • Hygiene • Hazardous scenes
Overview • Infectious diseases affect entire populations • Important to understand population demographics • Their ability to move internationally • Age distributions • Socioeconomic considerations • Genetic factors • Study of an infectious disease cluster is regional; consequences may be international. • Think of consequences of person-to-person contacts
Public Health Agencies • Local – that’s YOU! • State • Health dept • Federal • US DHS CDC & P • Monitors • Studies & researches • Manages • OSHA
Agency responsibility relative to isolation from exposure • Exposure plan • Maintenance and surveillance • Appointing a DO • Schedule of standards implemented • PPE • gowns • gloves • face shields • masks • protective eyewear
BSI • Procedures for evaluation of circumstances and counseling • personal, building, vehicular, equipment disinfection and storage • After action analysis • Correct disposal • Correct handling
Guidelines, Recommendations, Standards, Laws • PPE must be available to all employees at high risk • All employees must be offered HB vaccine • All high risk employees must be offered protection from bloodborne pathogens including TB testing, measles vaccination.
Host Defense Mechanisms • Nonspecific and surface defense mechanisms • Flora • Enhances effectiveness of surface barrier by interfering with establishment of agents • Can be responsible for infection • Skin • Intact skin defends against infection by: • Maintaining an acidic pH level • Preventing infection
GI System • Resident bacterial flora provides competition between colonies of microorganisms for nutrients and space; helps prevent proliferation of pathogenic organisms • Stomach acid may destroy some microorganisms • Eliminates pathogens through feces
Upper Respiratory system • Turbinates • Mucous • Mucociliary escalator • Normal bacterial flora • Lymph tissues of tonsils and adenoids permit rapid local immunological response
GU tract • Natural process of urination and bacteriostatic properties of urine help prevent establishment of microorganisms in GU tract • Antibacterial substances in prostatic fluid and vaginal fluid help prevent infection in GU system.
Internal Barriers • Protect against pathogenic agents when external lines of defense are breached. • Include • Inflammatory response • Imune response
Inflammatory response • A local reaction to cellular injury • Generally protective and beneficial • May initiate destruction of the body’s own tissue
Three separate stages • Cellular response to injury • Decreasing energy stores • Cell membrane deteriorates, begin to leak • Vascular response to injury • Capillary permeability increases, = edema • Leukocytes collect • Pagocytosis • Leukocytes engulf, digest, destroy invaders
Immune response • Possesses self-nonself recognition • Produces antibodies • Some lymphocytes become memory cells • Is self-regulated to activate only when invading pathogens IgG IgM IgA IgD IgE
B-cells • Produces antibody • T-cells • Processes antigen for B-cell, • Killer T cells are stimulated to multiply by presence of antigens on abnormal cells • Helper T cells turn on activities of killer cells • Suppressor T cells turn off action of helper and killer T cells • Inflammatory T cells stimulate allergic reactions, anaphylaxis, autoimmune reactions
Approach to call • Wear appropriate PPE • Patient Assessment: • Focused history and physical • History of present illness • Onset - gradual or sudden? • Fever • Antipyretic usage (ASA, APAP) • Neck pain or rigidity? • Difficulty swallowing, secretions? • How did sx change over time?
Past medical history • Chronic infections, inflammation • Use of steroids, antibiotics • Organ transplant and associated medicines • Diabetes or other endocrine disorders • COPD or respiratory complications
Detailed history and physical • Assess skin for temperature, hydration, color, mottling, rashes, and petechiae • Assess sclera for icterus • Assess patient reaction to neck flexion • Assess for lymphadenopathy in neck • Assess digits and extremities for purulent lesions
Upon disposition of patient, dispose of supplies, bag linen, disinfect ambulance and equipment • Reprocessing methods for EMS durable equipt. • Sterilization • High-level disinfection • Intermediate-level disinfection • Low-level disinfection
The Ryan White Act • Ryan Wayne White - 1971 – 1990 • Dx /c Hemophilia at 3 days old • Tx /c Factor VIII and blood transfusions • 1984 – Dx /c AIDS • 1990, 1996 – Ryan White law passed
What does it mean? • Employees must be notified within 48 hours if an exposure is found to have occurred. • Employers must name a DO to coordinate communications between hospital and agency
Individual Responsibilities • Be familiar with laws, regulations • Proactive attitude – infection control • Maintain personal hygiene • Attend to wounds • Effective hand washing after every patient contact • Remove or dispose of work garments- handle uniforms properly
Handle and launder soiled work clothes properly • Prepare food and eat in appropriate areas • Maintain general and psychological health • Dispose of needles and sharps appropriately • Don’t wipe face and/or rub eyes, nose, mouth etc.
Exposure does not necessarily equal infection • The chain of elements must be intact • Transmission can be controlled
HIV Hepatitis A Hepatitis B Hepatitis C Hepatitis non-ABC Tuberculosis Mengococcal meningitis Pneumonia Rabies Hantavirus Chicken pox Mumps We’ll talk about...
Rubella Measles Whooping cough Influenza Mononucleosis Herpes simplex 1 & 2 Syphilis Gonorrhea Chlamydia Scabies & Lice Lyme disease Gastroenteritis And these too
Infectious agents • Bacteria • Prokaryotic • Nuclear material is not contained within a distinctive envelope • self-reproducing without host cell – BUT require host for food, support • s/s depend on cells and tissues infected
Toxins - often more lethal than bacterium • Endotoxins • Exotoxins • Can be localized or systemic infection
Viruses • Eukaryotic • Nuclear material contained within a distinct envelope • must invade host cells to reproduce • Can’t survive outside of host cell
Other Microorganisms • Prions • Slow viruses – particles of protein • Accumulate in nervous tissue and brain tissue • Mad Cow Disease • Fatal familial insomnia • Alzheimers Disease • Parkinsons’ Disease
Fungi • Protective capsules surround the cell wall and protect fungi from phagocytes • Broad-spectrum antibiotics can cause fungal infections • Pneumonia, Yeast infections
ProtozoansSingle-celled microorganismsMore complex than bacteria • Live in soil – opportunistic infections – fecal-oral or mosquito bites • Malaria • Some forms of Gastroenteritis • trichomoniasis
Parasites – Helminths (worms) • Roundworms • Live in intestinal mucosa • S/S – abdominal cramping, fever, cough • Pinworms • Common in US • 20% of children in temperate climates are infected • Live in distal colon • S/S – anal itching • Hookworms • 25% world population – rare in US • Walking barefoot in contaminated area • S/S – epigastric pain, anemia
Human immunodeficiency virus (HIV) Slim disease • Present in blood and serum-derived body fluids • Directly transmitted person-person • Indirectly transmitted via • blood transfusion, organ transplant, contaminated needles
Statistics • US- 850,000 – 950,000 • >180,000 undiagnosed • Oregon – 5,599 (12/03)
International Travel • 'Patient Zero‘ - Gaetan Dugas • Analysis of several of the early cases of AIDS -infected individuals were either direct or indirect sexual contacts of the flight attendant. • The Blood Industry • In some countries such as the USA paid donors were used, including intravenous drug users. • This blood sent worldwide. • Also, in the late 1960's hemophiliacs benefit from Factor VIII. To produce the coagulant, blood from thousands of individual donors had to be pooled.
Drug Use • The 1970s - increase in availability of heroin following the Vietnam War and other conflicts in the Middle East, • the development of disposable syringes and the establishment of 'shooting galleries' provided another route. • What other theories have there been about the origin of HIV? • conspiracy theories - manufactured by the CIA vs genetically engineered.
Occurrence highest: • High-risk sexual behavior • IV drug abuse • Transfusion recipient between 1978-1985 • Hemophilia or other coagulation disorders requiring blood products • Infant born from HIV-pos. mother • Other factors • Coexisting STD’s (esp. with ulceration) • Penile foreskin
Causative agent - HIV-1 & HIV-2 • Seeks cell receptor CD4+ T cells • Found on surface of T helper cells • Both types are seriologically distinct but share similar characteristics HIV infected T-cell
HIV-1 is far more pathogenic; most cases world-wide are HIV-1, Group M • first case in US of HIV-1, Group O, identified in 6/96 • Est. AIDS dx through 2003 in US- 929,985. Adult and adolescent: 920,566 Males: 749,887 Females: 170,679 Children: 9,419 • HIV-antibody tests in US detect HIV-1 Group M, with 99% accuracy; HIV-1 Group O with 50-90%. • HIV-2 – milder sx, slower development – mainly in West Africa. US cases: 79
Initial case definition established by CDC in 1982. • 1987 & 1993; s/s include tuberculosis, recurrent pneumonia, wasting syndrome, HIV dementia, sensory neuropathy.
Classifications & Categories Category A • Acute retroviral infection • 2-4 weeks after exposure • Mono-like illness; lasts 1 – 2 weeks • Fever • Adenopathy • Sore throat
Transient decrease in CD4+T cell counts • Seroconversion; 6-12 weeks after transmission • CD4+T cell count return to normal levels • Asymptomatic infection; persistent generalized lymphadenopathy; gradual decline in CD4+T cell count
Category B • Early symptomatic HIV • Decreased CD4+T cell count • Common complications • Localized Candida infections • Oral lesions • Shingles • PID • Peripheral neuropathy • Fever/Diarrhea lasting more than one month
Category C • Late symptomatic HIV • Represents all AIDS-defining diagnoses • CD4+T cell count 0 to 200 per uL • Severe opportunistic infections • Bacterial pneumonia (Pneumocystis Carinii Pneumonia) • Pulmonary tuberculosis • Debilitating diarrhea • Tumors in any body system, including Kaposi’s sarcoma • HIV-associated dementia • Advanced HIV: CD4+T cell counts 0-50 per uL.