Virulence Factors
Name two virulence factors that allows a microbe to stick to body surfaces of a host.
adhesins (ex: Pseudomonas infections, plague, malaria)
or
fimbriae (ex: meningococcal meningitis)
What general type of pathogen causes all of the following diseases?
Hansen's disease, listeriosis, tularemia, cutaneous anthrax, & botulism
These are all bacterial diseases.
The specific pathogens are:
Hansen's (leprosy) - Mycobacterium leprae
listeriosis (bacterial meningitis) - Listeria monocytogenes
tularemia (rabbit or tick fever) - Francisella tularensis
anthrax - Bacillus anthracis
Name the disease caused by:
Clostridium perfringens
Gas gangrene (aka: gangrene)
What do all of the following have in common with regards to their mode of transmission?
gas gangrene, wound botulism, tetanus, & cutaneous anthrax
All require direct contact of bacterial endospores into a deep wound.
Name two diseases that can be prevented through proper wound care.
examples:
septicemia, folliculitis, gas gangrene, necrotizing fasciitis, cellulitis, SSSS, pyoderma/impetigo, botulism, Pseudomonas infections
NOTE: tetanus could also be included on this list, but it is prevented MUCH more effectively via routine vaccination
What form of treatment may be used for all of these diseases?
anthrax, endocarditis, Hansen's disease, bubonic plague, ehrlichiosis, & septicemia
These are all bacterial diseases that may be effectively treated with antibiotics.
Some may require immediate administration (ex: anthrax, septicemia) or long-term administration (ex: endocarditis) to be effective.
Some may also require other supportive measures, such as surgical removal of vegetations in endocarditis, etc.
Name the virulence factor that allows a microbe to avoid phagocytosis via camouflage.
Give one example disease.
capsule (ex: meningococcal meningitis, plague, etc.)
What general type of pathogen causes all of the following diseases?
rubella, shingles, & infectious mononucleosis
These are all viral diseases.
What general type of disease may be caused by any of these pathogens?
Listeria monocytogenes
Streptococcus agalactiae
Haemophilus influenzae
bacterial meningitis
aka:
"listeriosis"
"streptococcal pneumonia"
What is the mode of transmission for:
cryptococcal meningitis
inhalation of fungal spores
What method of prevention is shared by:
transmissible spongiform encephalopathy, listeriosis, toxoplasmosis, & brucellosis
avoid consumption of undercooked or contaminated foods
Name two diseases of the nervous system for which there is NO effective treatment & the only option is to "let it run its course".
transmissible spongiform encephalopathies (aka: prion diseases)
viral (aseptic) meningitis
poliomyelitis
Briefly explain how a ‘cytokine storm’ works as a virulence factor.
Give one example disease.
Cytokines released en masse trigger multiple aspects of immune defenses simultaneously.
ex: smallpox, septicemia
What general type of pathogen causes both:
impetigo & Lyme disease
They are both bacterial diseases.
Name the specific disease caused by each of the following:
Rubivirus causes...
Varicella-Zoster virus causes...
human herpesvirus 4 (HH4) (aka: Epstein-Barr virus) causes...
Rubivirus - rubella (aka: 'German measles')
Varicella-Zoster virus - chickenpox/shingles
human herpesvirus 4 (HH4) (aka: Epstein-Barr virus) - infectious mononucleosis
What do all of the following have in common with regards to their mode of transmission?
Dengue fever, West Nile encephalitis, & malaria
All require biological vector transmission via mosquitoes
What method of prevention is shared by:
anthrax, rabies, & brucellosis
animal vaccination, specifically:
anthrax - livestock
rabies - pets
brucellosis (aka: undulant fever) - all dairy producing livestock
Why won't antibiotics effectively treat the following diseases?
measles, poliomyelitis, West Nile encephalitis, & yellow fever
These are all viral diseases and "antibiotics" target bacteria.
NOTE: Only some viral diseases can be effectively treated with "antiviral" medications (ex: acyclovir for herpes), but they generally do not cure the infection.
Briefly describe how exotoxins serve as virulence factors.
Give one example disease & the specific type of exotoxin involved.
Exotoxins are secreted from living bacteria & target specific host cells/tissues/organs.
Examples:
Neurotoxins target neurons in tetanus or botulism
or
Exotoxin A triggers T-cell tissue damage (self-inflicted) in necrotizing fasciitis or Pseudomonas infections
What general type of pathogen causes both:
African sleeping sickness & Chagas disease
These are protozoan diseases.
The specific pathogens are:
African sleeping sickness - Trypanosoma brucei
Chagas disease - Trypanosoma cruzi
Name the disease caused by the spirochete named
Borrelia burgdorferi
Lyme disease
What do the following have in common with regards to their mode of transmission?
toxoplasmosis & rubella
Both may transmit vertically (mother to baby)
toxo - also via ingestion of undercooked contaminated meats
rubella - also via respiratory droplets
Name two specific ways to prevent insect-borne zoonotic disease transmission.
Give one example for each.
bed-netting to exclude mosquitoes (ex: malaria).
remove ticks promptly or use insect repellents containing DEET to avoid ticks (ex: Lyme disease, RMSF, anaplasmosis, ehrlichiosis)
remove mosquito breeding grounds (i.e., anything that holds water) (ex: malaria, Zika, West Nile encephalitis, yellow fever, dengue fever)
Explain the basic difference between:
preventing a disease with a vaccine
vs.
treating a disease with an antiserum
Give one example of a disease that might involve both.
Vaccines trigger an active immunological memory response before an exposure to protect the recipient long-term (ex: rabies vaccine).
Antiserum contains premade antibodies that may be given after an exposure (ex: anti-rabies IgG). NO memory cells are made so this passive immunization can only provide temporary protection.
Briefly differentiate these two virulence factors & give examples:
hyaluronic acid vs. hyaluronidase
Hyaluronic acid may be found in capsules to serve as camo from phagocytes. ex: impetigo (S. aureus)
Hyaluronidase is an enzyme that dissolves basement membranes, allowing microbe to invade deeper. Ex: necrotizing fasciitis (S. pyogenes)
What general type of pathogen causes all of the following diseases?
cryptococcal meningitis, pityriasis, & tineas
They are all fungal diseases.
The specific pathogens are:
cryptococcal meningitis - Cryptococcal neoformans
pityriasis - Malassezia furfur
tineas (jock itch, ringworm, etc.) - Tinea spp.
Name the specific diseases & their alternate names caused by each of the following:
Trypanosoma brucei vs. Trypanosoma cruzi
Trypanosoma brucei - African sleeping sickness (aka: African trypanosomiasis)
Trypanosoma cruzi - Chagas (aka: American trypanosomiasis)
What do all of the following have in common with regards to their mode of transmission?
tularemia, Lyme disease, ehrlichiosis, RMSF, & anaplasmosis
All require biological vector transmission via ticks
Name one vaccine preventable disease of each:
integumentary, nervous, & cardiovascular systems
integumentary: smallpox, measles, rubella, or chickenpox/shingles
nervous: tetanus, some forms of bacterial meningitis (meningococcal, pneumococcal, Haemophilus influenzae), poliomyelitis, rabies (limited use in humans; routine in pets)
cardiovascular/lymphatic: yellow fever, brucellosis, & malaria (vs. deadliest strain P. falciparum; as of 2021)
Name TWO nervous system diseases for which post-exposure IgG administration is a key method of treatment.
tetanus
rabies
foodborne botulism
Briefly explain how antigen shifts serve as a virulence factor.
Give one example disease.
Immunological memory is avoided when organisms can change their surface antigens (glycoproteins).
ex: African sleeping sickness, Lyme disease, or malaria
Name the general type of organisms that make:
endospores vs. spores vs. cysts vs. oocysts
Give one example disease for each.
endospores = bacterial resting stages (from G+ members of Genera Clostridium, Bacillus, & Clostridioides; Ex: tetanus, botulism, gangrene, C-diff)
spores = fungal reproductive structures (Ex: chromoblastomycosis, phaehyphomycosis, mycetomas, sporotrichosis, cryptococcal meningitis)
cysts = helminth reproductive structures (Ex: cysticercosis; tapeworms)
oocysts = protozoan reproductive structures (Ex: primary amebic meningoencephalopathy)
Name the specific diseases caused by each of the following:
Enterovirus vs. Lyssavirus vs. Arbovirus
Enterovirus - poliomyelitis (aka: polio virus)
Lyssavirus - rabies
Arboviruses (arthropod-borne; transmitted by mosquitos) - Zika & WNV encephalitis
What do all of the following have in common with regards to their mode of transmission?
Leishmaniasis, African sleeping sickness, river blindness, Chagas' disease, & bubonic plague
All require some kind of biological vector transmission via NON-mosquito insect vectors
The specific vectors are:
Leishmaniasis - female sand flies
African sleeping sickness - tse-tse flies
river blindness - black flies
Chagas' disease - true bugs (Triatoma)
bubonic plague - fleas
Name TWO diseases for which one mode of prevention is typically prophylactic antibiotics.
malaria - anti-protozoan meds for travelers to endemic regions
endocarditis - anti-bacterial meds before dental procedures/surgeries for high risk patients
HIV - anti-viral meds; PrEP (pre-exposure prophylaxis)
Name TWO diseases for which avoiding respiratory droplets from an infected person is a good method of prevention.
smallpox, chickenpox, rubella, measles, bacterial meningitis
also: pneumonic plague (respiratory chapter)
Name one virulence factor that allows a microbe to avoid desiccation.
Give one example disease.
mycolic acid (ex: leprosy)
What general type of organism causes all of the following diseases?
yellow fever, infectious mononucleosis, & dengue hemorrhagic fever
They are all viral diseases.
The specific pathogens are:
yellow fever - Flavivirus
infectious mononucleosis - Epstein-Barr virus
dengue hemorrhagic fever - Dengue viruses (n= 4)
Name the disease most commonly caused by:
Viridans streptococci
endocarditis
What do all of the following have in common with regards to their mode of transmission?
measles, smallpox, chickenpox, & most forms of bacterial meningitis
respiratory droplet transmission
* listeriosis is one exception for bacterial meningitis; it is via ingestion rather than droplets
Name TWO diseases for which avoiding ticks is the key method of prevention.
RMSF (rocky mountain spotted fever)
ehrlichiosis/anaplasmosis
tularemia
Lyme disease
Name TWO diseases for which avoiding direct contact with an infected person is the best method of prevention.
direct skin-skin contact: SSSS, impetigo, conjunctivitis, herpes, cutaneous/superficial mycoses
also via fomites: warts, piedra, pityriasis, tineas
via saliva: mono
via wounds/burns: necrotizing fasciitis & Pseudomonas
via long-term exposure: leprosy
via bodily fluid contact or placental: CMV
Differentiate between the terms:
pyrogenic vs. pyogenic
Give one example disease for each in which the pathogen uses them as virulence factors.
pyrogenic = fever producer (ex: impetigo – Staphylococcus aureus)
pyogenic = pus producer (ex: necrotizing fasciitis – Streptococcus pyogenes)
What do these two diseases have in common with regards to the general type of pathogen AND mode of transmission?
malaria & leishmaniasis
These are both protozoan diseases transmitted via biological vectors.
The specific pathogens & vectors are:
malaria - Plasmodium spp. via mosquitos
leishmaniasis - Leishmania spp. via sand flies
Name the TWO diseases caused by members of the Genera:
Clostridium
botulism - Clostridium botulinum
tetanus - Clostridium tetani
What do all of the following have in common with regards to their mode of transmission?
poliomyelitis, listeriosis, brucellosis, TSEs, tularemia, & most forms of botulism
ingestion; specifically of:
contaminated water (polio)
undercooked meats/cheeses (listeriosis)
unpasteurized dairy products (brucellosis)
contaminated meat (TSEs; prion diseases)
contaminated water or meat (i.e. rabbits) (tularemia)
ingestion of toxin (i.e., improper canning) (foodborne botulism)
ingestion of endospores in raw honey (infant botulism)
Which of these pathogens cause vaccine-preventable forms of bacterial meningitis?
A) Streptococcus pneumoniae
B) Listeria monocytogenes
C) Streptococcus agalactiae
D) Haemophilus influenzae
E) Neisseria meningitidis
A) Streptococcus pneumoniae ("pneumococcal")
D) Haemophilus influenzae (HiB)
E) Neisseria meningitidis ("meningococcal")