Infectious Diseases Flashcards
Etiology
Cause of injection usually by pathogenic microorganisms
Infection
Major cause of disease
Mortality
- condition of being subject to death
- how long a person will live with or without a disease
Morbidity
- illness or abnormal condition or quality
- condition or way they will live with the disease
Communicable or Contagious Diseases
Aka: Community Acquired
- Diseases that spread from one person to another
Colonization
-Individual may have the organism in or on the body and not get the disease and may not cause an infection
Bacteria
-unicellular organism classified by shape
Cell wall
- humans and animals do not have this
- gram + or gram - cell walls differ
Cell Membrane
- semipermeable
- selectively controls movement
Cytoplasm
- Contains RNA, DNA, Plasmids
- DNA fragments are important in drug resistance
- also important for metabolism growth and unique characteristics of the bacteria
Capsule/slime layer
- Lines outside cell wall making it slippery
- interferes with phagocytosis
Flagellum
- Tail like growth
- used for motility
- spiral whipping to propel
Pili or Fimbrae
- found on Gram(-) bact
- Attaches bacteria to tissue
- Transfers DNA to other bacterium causing mutation
Viruses
- Intracellular parasite
- Requires a living host cell for replication
Structure of viruses
- Protein coat or capsid
- Core of DNA or RNA (content of these provides method of classification for viruses)
- Outer protective envelop making harder to latch onto slippery outside
Fungi
Infection from single cell yeasts or multicellular molds
Fungi: 3 Means of Production
- budding
- Extension of hyphae (Filaments)
- Production of spores (mold spores)
Protozoa
-unicellular organism with animal like characteristics, mobile, lack cell wall
Mycoplasma
- smallest cellular microbe
- lacks cell wall
- reproduces by binary fission
- Causes 15-20% of all pneumonia in developing countries
Direct contact
No Intermediary
-Microbes in blood, body, secretions, lesions
Indirect Contact
Involves intermediary
-contaminated food, water, bed linens
Droplet
- Expelled from the body and inhaled by another person
- Fall on surface that is touched by someone else
Vector-Borne
insect or animal intermediary
Example: mosquito➡️malaria
Nosocomial
Acquired in a health care facility
- Dirty hands major culprit
- most common UTI and Pneumonia
Respiratory Droplet Infections
- Common Cold
- influenza
- small pox
- mumps
- pertussis
- Pneumonia
- polio
- strep
- TB
Incubation period
Time between entry of organism into system and the appearance of clinical sign (hours-months)
Prodromal Period
General malaise varying in severity
-more evident in some infections
Acute period
Infectious disease develops fully
-length period varies with pathogen/host resistance
Recovery
Follows acute period when the infection either goes away
Chronic infection
Some organisms remain in the body
-clinical symptoms mild
Death
- Infection spreads to the body
- Septicemia (form of shock causing muli-system organ failure )
Leukocytosis
⬆️ WBC seen in bacterial infection
Leukopenia
⬇️ WBC from normal count
Viral infection
Increased neutrophils =
Acute infection
⬆️ lymphocytes and monocytes=
Chronic infection
Anthrax
- Spore forming bacteria found in infected live stock
- transmission: direct contact
Anthrax Symptoms
- initially acts like a flu
- if worsens
- severe difficulty breathing
- shock
- meningitis
West Nile Virus
- bite from infected mosquito
- infection crosses the BBB and causes inflammation of brain
Etiology of West Nile Virus
Vector borne transmission
-Incubation 3-14 days before symptoms detected
West Nile symptoms
80% of victims are asymptomatic
- rash
- swollen lymp glands
- coma paralysis
- disorientation, tremors
- fever headache rash
Diagnosis for West Nile virus
- get patients full clinical history (clinical picture)
- ELISA blood test (differentiates different Ab in the blood)
- Detects Ab to the virus within first few days of onset
Anthrax Treatment
- **antibiotics NOT used for viruses
- alleviates symptoms (analgesics)
- fluids and rest
Common Cold
Acute Cortez’s
Upper respiratory infection
Common Cold Etiology
Causes by approx. 200 different viruses
- Rhinoviruses cause 1/2 of colds in adults
- followed by bacterial infection
Common Cold Signs & Symptoms
- nasal drainage
- watery eyes
- sore throat and cough
- slight fever
- incubates for 2-5 days from exposure
Common Cold Diagnosis
Clinical picture
-may do CBC & Sputum culture to rule out more serious problems
Common Cold Treatment
- clears in 3-7 days
- rest, liquids, and decongestants
Influenza Etiology
Viral epidemic: epidemic that occurs in cycles around the world
Influenza mixovirus 3 kinds
Type A: most common
Type B: virus mutates frequently
Type C: transmitted by respiratory droplets
Influenza Signs & Symptoms
sudden Onset
- fever chills
- headache, myalgia, malaise
- sore throat cough (dry)
- secondary bacterial infection may develop
Influenza diagnosis
Clinical picture
- presence from epidemic in area
- check throat culture
- immunofluorescence (nasal swab) to detect viral Ag
Influenza treatment
-analgesic, antipyretic, rest, liquids
Anti-viral drugs
Ebola Hemorrhagic Fever Etiology
- 4 or 5 identified Ebola viruses can cause disease in humans/primates
- through Bats
- Direct contact transmission through bodily fluid
Ebola Hemorrhagic Fever: Signs & Symptoms
- fever > 38.6
- headache
- muscle pain, weakness
- diarrhea
- vomiting
- abdominal pain
- lack of appetite
Ebola Hemorrhagic Fever: Diagnosis
Nonspecific symptoms hard to diagnose
-lab tests needed to confirm
Ebola Hemorrhagic Fever: treatment
Staphylococcus aureus
- Gram(+) bacteria, has cell wall
- grows on human skin
- may be carried in nasopharynx 15-20%of ppl
- common cause of suppurative infections(pus forming)
Staphylococcus aureus: Typical infections
- boils
- impetigo
- cellulitis
- bacterial endocarditis
- toxic shock syndrome
boils
Furuncles
-occur in and around hair follicles
Lack of hygiene
impetigo
Skin infection spread by contact
cellulitis
Spreading infection of skin and connective tissues
-severe inflammation
Bacterial endocarditis
Caused by S. aureus septicemia
-after heart surgery valve replacement
toxic shock syndrome
Caused by S. aureus endotoxins
-aseptic, wide spread exposure to S. aureus
MRSA
Methacillin resistant staphylococcus aureus
- resistant to most common antibiotics
- not usually prob in healthy ppl
- spreads easily in hospitals
MRSA: treatment
Treat with Vancomycin along with other antibiotics
MRSA: spread through
Close contacts with individuals
- using other ppls towels
- wound dressing
- close contact sport
- *does not spread in air
VRE
vancomycin Resistant Enterococci
-lives for long time and extremely hard to get rid of
Measles: Etiology
rubeola virus
- spread by Airborne secretions
- 10 to 20 day incubation
Measles: signs and symptoms
- fever
- photophobia
- Rash follows in 3-7 days
Measles: Diagnosis
History of exposure and clinical picture
-leukopenia (⬇️WBC count)
Measles: treatment
Rest
Darkened room
Antipyretic
Rubella (German measles): Etiology
-rubella virus
-Spread by contact with nasal/oral secretions
14-21 day incubation
Rubella signs and symptoms
Similar to rubeola, but milder with shorter course
Rubella: Diagnosis
- history of exposure and clinical picture
- throat culture or serum Antibodies for definitive diagnosis
Rubella: Treatment
Bed rest
Antipruritics (relive itching)
Antipyretics
Mumps: Etiology
Virus spread by Saliva, airborne route
-18 day incubation
Mumps: s&s
Inflammation of one or both parotid glands that could cause aspiration due to swallowing troubles
- headache
- fever
- earache
- orchitis in adult male
Mumps: diagnosis
History of exposure and clinical picture
Mumps: treatment
- analgesics
- antipyretics
- soft or liquid diet
Varicella (chicken pox): etiology
-Varicella-zoster virus
-spread by direct contact or Respiratory secretions
13-17 day incubation
Varicella Signs and symptoms
Pruritic rash goes from➡️papules➡️vesicles➡️crusts
-fever and malaise
Varicella: Diagnosis
History of exposure and clinical picture
Varicella treatment
Isolation until scabs disappear
- antipruritics
- antipyretics
Pertussis (whooping cough): etiology
-Bordetella pertussis bacillus
-spread by respiratory Droplets, direct or indirect contact with nasal secretions of infected host
7-10 day incubation
Pertussis; signs and symptoms
- Catarrhal stage: symp similar to common cold
- Paroxysmal Stage: violent cough, thick mucous obstructs airways
- Decline stage: gradual improvement
Pertussis: diagnosis
History of exposure and clinical picture
- leukocytosis B pertussis present in respiratory secretions
Pertussis: treatment
Antibiotics most effective in catarrhal stage
- rest, fluid, adequate diet
- removal of thick secretions
