unit 15 Flashcards
Meninges
-membrane that covers brain/spinal cord
-low amount of complements
-low phagocytic cells
3 membranes of brain
dura
pia mater
arachnoid
CSF
- found between arachnoid / pia mater
- acts as blood brain barrier (protective mechanism for brain)
What can pass through the blood brain barrier?
penicillin/ lipid soluble drugs
Meningitis
inflammation of meninges
Encephalitis
inflammation of brain
Meningocencephalitis
inflammation of meninges / brain
what 2 microbes are responsible for majority of bacterial meningitis in US
Neisseria meningitidis and meningoccal meningitidis
bacterial meningitis
- virulent
- symptoms caused by endotoxins
- transmission = droplet aerosols/ secretions
Neisseria meningitidis
- affects young adults/ elderly
- vaccine available
- blunt force to head makes microbe found in throat/nose -> brain
Streptococcus pneumoniae (pneumococcal meningitis)
- leading cause of meningitis in US
- has capsules (virulent)
-high mortality rate
-vaccine available
Haemophilus infleunzae type B. (influenzal meningitis)
- used to be leading causing of meningitis
- virulent (capsule)
-normal throat flora - affects children under age of 4
-Hib vaccine decreased incidence
Group B streptococcus (GBS)
- meningitis / neonatal sepsis
- normal flora of vagina
- affects newborns
- pregnant women screened for GBS / given antibiotics during labor to prevent transmission
Listeria monocytogenes
- gram + rod
- food borne illness (dairy products)
- psychrophile/mesophile
- can cause still birth
-avoid eating ready to eat meats if pregnant
Tetanus (clostridium tetani)
- gram + rod , anaerobe, endospores
- common in soil/animal waste
- causes muscle spasms/ contractions
-releases tetanospasmin (neurotoxin)
How do you get tetanus
deep punctures wounds with minimal bleeding
- bleeding causing microbe to die to exposure to oxygen
vaccine for tetanus
Dtap/Dpt
treatment for tetanus
-toxoid/ tetanus immune globulin (TIG)
- debridement/antibiotics
- if toxin attached to nerve cell, therapy no use
Botulism (clostridium botulinum)
- neurotoxin
- gram + rod with endospores/anaerobe
- prevents release of ach
-infects CNS not gi tract
-ingestion of endospores not dangerous/ toxin is deadly
Prevention of Botulism
- pressure cooker kills endospores
-toxins destroyed by boiling - nitrates added to meats to prevent growth
Infant botulism
- intestinal flora of 1 year old
- due to eating contaminated soil/honey
- treatment = antitoxins to specific toxin
- botulism toxin = botox
Leprosy’s (Hansen’s disease)
- Mycobacterium leprae
- acid fast rod
- 30 C opti temp
- found in armadillos / nasal secretions and lesion fluid
- mode of infection = contact w nasal secretions/contaminated fomites
2 forms of leprosy
lepromatous / tubercoloid (neural)
Lepromatous
- skin cells infected
-large disfiguring nodules
-severe
tubercoloid (neural)
- regions of skin lose sensation
- surrounded by small nodules
- depigmentation
- treatment = rifampin/ sulfone
- isolation no longer required
Aseptic meningitis (viral meningitis)
- more common than bacterial meningitis / often milder
Poliomyelitis (Polio)
- only found in humans (picornavirus)
- transmission = fecal/oral
- diagnosis = stool/throat testing (antigen)
-paralysis
2 type of vaccines for polio
Sabins vaccine / Salk’s vaccine
Salk vaccine (inactivated)
- injection
- 100% safe
- virus is killed
-not immunogenic/antigenic (more doses are needed)
Sabin vaccine (tri-oral)
- taken orally
- very antigenic
- not 100% safe due to virus not being completely killed
Rabies (rhabdovirus)
- bullet shaped
- transmission = bite/saliva from infected animal
-fatal encephalitis
-diagnosis = alive-viral antigens in saliva serum, CSF , dead- brain tissue CPE
-vaccination for animals/humans
treatment for rabies
- immune globulin / vaccine
Viral encephalitis
-EEE, west nile, zika viruses
- mosquito= biological arthropod vector
EEE virus
from horses
West nile virus
from birds/pidgeons
Zika virus
transmitted sexually from mother -> fetus
male can host virus up to 6 months in semen
Cryptococcosis
dimorphic fungi
test by checking cerebral spinal fluid
-caused by pidgeons feces
-most common cause of fungal death in US
-mostly found in urban areas
African Trypanosomiasis
-causes disease in CNS
-coma / death if not treated
- host = humans/ domestic / wild animals
- mode of infection = Bite of infected tsetse fly
-Trypanosoma Bruci
-
suramin and pentamidine / try to control insect population
treatment for African Trypanosomiasis
Septicemia
- microbial growth/toxins in blood
- usually focal infection
- gram + / gram - (endotoxins)
- inflamed lymph vessels under skin (lymphangitis)
Puerperal sepsis or fever
-uterine infection
-result of childbirth / abortion
- s. pyogenes
Endocarditis
- infection of inner lining of heart muscles
Rheumatic fever
-type III immune complex reaction
- untreated s. pyogenes throat infection lead to thsi
- causes arthritis / inflammation of heart (permanent damage)
Tularemia (rabbit fever)
- zoonotic disease
- highly infectious
- microbe = Francisella tularnesis
- mode of entry = ingestion , cutaneous , inhalation
- treatment = tetracycline
-gram - rod
Brucellosis (undulant fever)
- Brucella
- milk borne pathogen
- world’s most common zoonotic disease
- diagnosis = serological testing
- mode of entry = inhalation / airbourne
- treatment = prolonged antibiotic
Anthrax (Bacillus anthracis)
- gram + rod w endospores
- primarily disease of grazing animals (cattle/sheep)
- people who handle wool animals / hides / animal products at risk
- virulent (endotoxin / capsule)
Anthrax (human disease)
- cutaneous black scabs
- transmission = ingestion / inhalation (woolworters disease)
- vaccine
- treatment = ciprofloxacin or doxycycline
Gas gangrene (clostridium perfringens)
- gram + rod w endospores / anaerobe
- soft tissue death due to ischemia (loss of blood) -> necrosis
- grows on nutrients released from dead/living cells
- ferments tissue carbs
- produces toxins/ gas
Treatment for gas gangrene
- debridement
- antibiotics
- hyperbaric cuff/ chamber
Pasteurella multocida
- embedded in teeth/ gum of animals
- higher infection rate with cat bites than dog bites
Black death (Yersinia pestis)
- mode of entry = rat flea bites / contact with various animals
- dark blue / black areas of skin due to hemorhagging
- vaccine available
3 types of plague or blackdeath
bubonic
septicemic
pneumonic
Bubonic
- most common
-buboes (asbscesses of lymph nodes) - 50 ->75% mortality
Septicemic
- communicable
- 90% mortality
Pneumonic
-communicable
- 100% mortality
treatment for black death
streptomycin/ tetracycline
Lyme disease
- most common tick borne disease in US
- borrelia burgdoferi
- found in field mice/ deer
- biological arthropod vector = deer tick
- diagnosis = serological tests/ antibody tests
1st stage of lyme disease
75% bull eyes rash in 2 weeks of bite
flu like symptoms after rash
2nd stage of lymes disease
- heart irregularities
- neurological impairment
- facial paralysis / meningitis / encephalitis
3rd stage of lymes disease
- arthritis as early as several months
- large doses of anitbiotics required
- resembles later stages of syphilis
treatment for lyme’s disease
tetracycline / doxycycline
Typhus (Rikettsia sp.)
- biological arthropod vectors
- inflammation causes blockage of small blood vessels/ ruptures of vessels
- treatment = tetracycline / chloramphenicol
Epidemic typhus (lice)
- disease of war, filth, poverty, famine
- vaccines for military
- found in louse feces/ rubbed into wound when bitten host scratches bite
Rocky mountain spotted fever (wood/dog tick)
- best known Rickettsial disease in US
- rash similar to measles but appears on palms/ soles
- fever/severe headache
