Ch. 12 - Soilborne and Arthropodborne Bacterial Diseases Flashcards
Anthrax
soilborne bacterial disease
causative agent: bacillus anthracis (Gram pos)
endemic zoonotic disease - large herbivores ingest spores while grazing
bacillus anthracis produces a capsule and 3 exotoxins - thick capsule impedes phagocytosis
endospores germinate rapidly on contact with human tissue - produce vegetative cells
Treatment: penicillin, ciproflaxin
Bioterrorism: esp inhalation anthrax and cutaneous anthrax
-in mail 2001
Inhalation Anthrax
also, woolsorter’s disease – contaminated dust (sheer sheep, tan hides, etc)
highly lethal (w/o early treatment)
form of pneumonia: chills, cough, fever, SOB
Intestinal Anthrax
from contaminated and undercooked meat
acute inflammation of intestinal tract
nausea, vomiting, ab pain
Cutaneous Anthrax
skin abrasions from contact with spore-contaminated animal products (eg shaving bristles)
develop into black necrotic sore = eschar
Tetanus
soilborne bacterial disease
causative agent: Clostridium tetani (Gram pos, endospores)
spores enter body through deep puncture wound; germinate (in dead O2 free tissue of wound) into vegetative bacilli; produce several toxins
produce neurotoxin (tetanospasmin) - blocks inhibition of muscle contraction (NT GABA) – constant spontaneous impluses to motor neurons – muscle spasms and stiffness
formerly lockjaw (jaw muscle stiffness)
Treatment: penicillin and antitoxins
Immunization: TDaP, booster every 10 years after childhood vaccines (DTaP)
Gas Gangrene
soilborne bacterial disease
causative agent: Costridium perfringens (anaerobic, Gram pos)
produce group of toxins and hydrolytic enzymes
endospores in contaminated dirt – introduced through severe open wound – spores germinate in wound – ferment muscle carbs and decompose musc protein
dead tissue (myonecrosis) blocks blood flow – gangrene and gas below the skin (from muscle tissue being fermented) –> blue/black tissue necrosis
Treatment: Debridgement, hyperbaric oxygen chamber
Arthropod
invertebrate having joint limbs and a segmented body with an exoskeleton made of chitin
arthropod borne infections transmitted by insects (mosquitoes, sand flies) and arachnids (ticks, mites)
act as vectors - living organism that transmits disease agents –> acquire disease from taking blood meal from another animal
characterized by high fever and body rash
Plague
arthropod borne bacterial disease
causative agent: Yersinia pestis (facultative, gram negative)
killed about 40 million in Europe during middle ages
3 pandemics: 542 CE, Black Death (1300s), late 1800s
Treatment: antibiotics (stretomycin, doxycycline)
usual staining property = bipolar staining - stains heavily at poles of cell; safety pin appearance
Sylvatic Plague
carried in rodents/prairie dogs - spread by their fleas
SW USA
Urban Plague
from rodents to humans by flea bites
Bubonic Plague
1/3 forms of plague
cells accumulate in bloodstream, localize in lymph nodes = buboes
painful swellings
resist phagocytosis – multiply in phagocytes
main virulence factor - F1 capsule
Septicemic Plague
1/3 forms of plague
= black death
spreads through bloodstream (hematogenous spread)
purple/black splotches from hemorrhages
symptoms: high fever, diarrhea, pain – lead to meningitis
Pneumonic Plauge
1/3 forms of plague
spread via respiratory droplets – when septicemic infections progress to lungs
highly contagious, extremely fatal
suffer cardiovascular collapse w/i 2-3 days
Lyme Disease
arthropod borne bacterial disease
causative agent: Borrelia burgdorferi (gram negative spirochete)
transmission: tick bite
ticks - live/mate in fur of deer
blood meal 24-36 hrs – suck blood, defecate into wound – spirochetes transmitted –> tick must remain attached for 24 hours
variable incubation period (3-31 days)
Stage 1: bull’s-eye rash; fever, aches, flu-like symptons; will not itch!
Stage 2: spread to skin, heart, nervous system, and joints = joint/muscle pain
Stage 3: chronic arthritis and swelling in the joints
Treatment: amoxicillin, doxycylcine in early stages
