Infectious Disease Prevention & Immunoprophylaxis Flashcards
A biological attack with intentional release of viruses, bacteria, or other germs that can sicken or kill people, livestock, or crops
Bioterrorism
the processing of microbes or toxins in a manner that would ensure a devastating effect following release
Weaponization
Features of Biologic Agents Used as Bioweapons
10
1. High morbidity and mortality rates
2. Potential for person-to-person spread
3. Low infective dose and highly infectious by aerosol
4. Lack of rapid diagnostic capability
5. Lack of universally available effective vaccine
6. Potential to cause anxiety
7. Availability of pathogen and feasibility of production
8. Environmental stability
9. Database of prior research and development
10. Potential to be “weaponized”
- Easily spread person - person
- High mortality and morbidity
- Requires special action for public health preparedness
- Potential for public panic and social disruption
is what category
category A - high priority
- Moderately easy to spread
- Low to moderate morbidity and mortality
what category?
category B - mid priority
- readily available
- Could be engineered for mass spread in the future
- Potential for major health impact
what category?
category C - lowest priority
what are the category A organisms
6
- Anthrax -(Bacillus anthracis)
- Botulism - (Clostridium botulinum toxin)
- Plague - (Yersinia pestis)
- Smallpox - (Variola major)
- Tularemia - (Francisella tularensis)
- Viral Hemorrhagic Fevers
* Arenaviruses: Lassa, New World (Machupo, Junin, Guanarito, and Sabia)
* Bunyaviridae: Crimean-Congo, Rift Valley
* Filoviridae: Ebola, Marburg
what are the category B organisms
13
- Brucellosis (Brucella spp.)
- Epsilon toxin of Clostridium perfringens
- Food safety threats (e.g., Salmonella spp.,
- Escherichia coli 0157:H7, Shigella)
- Glanders (Burkholderia mallei)
- Melioidosis (Burkholderia pseudomallei)
- Psittacosis (Chlamydophila psittaci)
- Q fever (Coxiella burnetii)
- Ricin toxin from Ricinus communis (castor beans)
- Staphylococcal enterotoxin B
- Typhus fever (Rickettsia prowazekii)
- Viral encephalitis (alphaviruses [e.g., Venezuelan, eastern, and western equine encephalitis])
- Water safety threats (e.g., Vibrio cholerae, Cryptosporidium parvum)
what diseases are category C
Emerging infectious diseases threats such as Nipah, hantavirus, SARS or MERS coronavirus, and pandemic influenza
what are the 3 forms of anthrax
-
GI
* Contaminated meat; unlikely result of bioterrorism
2.Skin / Cutaneous
* Spores enter skin ⇾ papule ⇾ painless vesicle ⇾ necrotic eschar -
Resp
* Most likely due to bioterrorism
* Fever, fatigue, malaise, N/V, cough, SOB ⇾ pneumonia ⇾ pleural effusions ⇾ death
how do you diagnose anthrax
- Prompt recognition key
- Culture blood, skin lesion, resp secretions
- Antibodies
tx for anthrax
- Antitoxin
- cipro, clinda
post-exposure/prophylaxis of anthrax
- vaccination available
- cipro, doxy, amoxicillin
how long is tx and proyphylaxis for anthrax and why?
lasts up to 60 days due to persistence of ungerminated spores in the resp tract
what is the only bioterrorism agent that is non-living but one of the most potent toxins in existence and extremely poisonous
Botulism
which toxin has 7 forms and prevents the release of acetylcholine, leading to flaccid paralysis of muscles
botulism
pt comes in with multiple cranial nerve palsies leading to descending flaccid paralysis
Diplopia, dysphagia, dysarthria, dry mouth, ptosis, dilated pupils, fatigue, extreme weakness
what could they been infected with
Botulism
diagnosing Botulism
Toxin immunoassay
tx for botulism
Supportive
* Intubation, mechanical ventilation, parenteral nutrition
* Equine antitoxin if dx early in disease
* Weeks to months of regeneration of new motor neuron synapses w/in the muscle cell
NO approved FDA vaccine
2 main types of plague, including presentations
-
Bubonic plague - results from bite of plague-infected rat flea
* Painful LAD w/ necrosis, fever, bacteremia ⇾ septicemia ⇾ death
* buboes
* Extensive ecchymosis and necrosis of digits and nose -
Pneumonic plague - inhalation of the bacteria
* Fever, cough, hemoptysis, and GI Sx
* Pneumonia ⇾ pleural effusion ⇾ lung consolidation ⇾ death
* Mortality 84%
diagnosing the plague
- Blood cultures and / or cultures of buboes, sputum
- Antibodies
tx for plague
- gentamicin
- streptomycin
- doxycycline
- chloramphenicol
prophylaxis of plague
- doxycycline
- levofloxacin
course of smallpox
- Exposure from aerosolized droplets from close contact w/ infected person
- Virus infects host
⇾ spreads to lymphoid tissue
⇾ localized infection of skin dermis
⇾ 2-14 days later ⇾ fever, malaise, HA, N/V, back pain, rash (maculopapular to face and extreme
⇾ spreading to trunk ⇾ turn to vesicles, then pustules, then scabs), mouth ulcers - Like varicella, pt is assumed no longer contagious when all lesions have formed scabs
- Death usually from severe systemic illness
how to diagnose smallpox
- Culture, PCR
- Antibodies
tx for smallpox
Strict isolation
Supportive measures only
Antivirals have not really been studied
which bioterrorism agent is Weaponized through either aerosol or in drinking water
Tularemia
microbiology of Tularemia
- Non-spore forming, but may survive weeks on surfaces
- Not spread person ⇾ person, but as little as 10 organisms may infect the host
-
Infection from insect bites or environment contamination - ticks and fleas bite an infected host and pass along to humans
also known as “rabbit fever” or “deer fly fever”
s/s of tularemia
1-14 days post exposure
1. Inflammation of the airways
* Pharyngitis, pleuritis, bronchopneumonia
2. Fever, HA, chills, fatigue, malaise
3. Conjunctivitis and exanthems possible
4. 50% - infiltrate on CXR; hilar adenopathy w/o infiltrate also possible
how do you diagnose tularemia
Gram stain or cultures of infected tissues or blood
tx for tularemia
- streptomycin or doxycycline
- also gentamicin, chloramphenicol, ciprofloxacin
no vaccines
s/s of viral hemorrhagic fevers
Fever, myalgia, prostration, DIC w/ thrombocytopenia and capillary hemorrhage
diagnosing viral hemorrhagic fevers
- > 38.3 ℃ (or 101 ℉) for at least 3 wks with at least 2 of the following (in the absence of another cause)
* Hemorrhagic or purpuric rash
* Epistaxis
* Hematemesis
* Hemoptysis
* Hematochezia - Serological testing for antigen and antibody; PCR - sent to the CDC
tx for viral hemorrhagic fevers
No approved treatment or vaccine
Experimental - antibody cocktails and ribavirin
3 main categories for transmission-based precautions
-
Contact precautions
* Gown and gloves required for pt or environment contact
* Sometimes above needed to even enter patient room -
Droplet precautions
* Surgical mask required w/in 3 feet of patient -
Airborne infection isolation
* Negative pressure isolation room
* Respirator must be worn
what are the types of PPE
-
Gloves
* blood, body fluids, secretions, excretions, mucous membranes, non-intact skin, or contaminated equipment -
Gowns
During procedures when contact of clothing, exposed skin w/ blood/body fluids, secretions, excretions, or body fluid is anticipated -
Mask / Goggles or Face shield
Any activity which may result in splashes or sprays of blood, body fluids, secretions, or excretions
what are the types of immnunity
-
Active immunity - induced by vaccines prepared from bacteria or their products
* Capsular polysaccharides, inactivated protein exotoxins (toxoids), killed bacteria, or live-attenuated bacteria -
Passive immunity - administration of preformed antibodies in preparations called immunoglobulins
* May be used as prevention or treatment of certain bacterial disease
* Examples: tetanus antitoxin, botulinum antitoxin, diphtheria antitoxin - used for tx and prevention
what are the types of vaccinations
-
Inactivated - dead virus
* More stable
* Safest form
* Weaker immune response
* Often requires multiple doses or boosters
* Examples: seasonal influenza, polio -
Live, attenuated - live but weakened virus
* Does not cause active disease (typically)
* Provides greatest immunity
* Examples: measles, mumps, varicella -
Subunit Vaccines
* Contain only antigens
* Less risk of adverse reactions
* Very time-consuming to make
* Example: Hep B -
Toxoid Vaccines
For bacterial infections that secrete toxoids
Inactivated toxoids
Examples: tetanus, diphtheria, pertussis -
Conjugate Vaccines
* Works against bacteria w/ a cell wall
* Produce synthetic product containing cell wall similar to the bacteria
* Examples: HIB type B vaccine, Pneumococcal (Prevnar) -
Once Experimental, now Realistic
* DNA vaccines / RNA vaccines - Covid-19 vaccines
* Recombinant vector vaccines
* Use a live bacteria as a vector
CI for vaccines
- Severe allergic reaction - anaphylaxis
- Pregnancy and severe immunosuppression - no LIVE vaccines, including live-attenuated vaccines