Eating habits - 9th set Flashcards
disease transmission is either
direct or indirect
indirect transmission includes (VVF)
VVF
vehicle, fomite and vector
vehicle transmission is (fawb in car)
FAWB
agent’s spread is via a medium or “things”. water, body fluids, food and airborne
vector tranmission is (T2)
mechanical and biological
body fluid transmission (blood, sweat HHHH)
- via blood, urine, saliva and other body fluids ( sweat, rectal fluid etc ) - potential pathogens can enter via conjunctiva, or break in skin or mucous membrane - some are routinely shedded
Ex: HIV, herpes, hepatitis agents, HPV - now known to be transmitted via semen too
food transmission is caused by…
poorly processed, cooked or refrigeration contributes to pathogen survival and transmission
most food pathogens are inactivated…
by acidic gastric environment, surviving ones cause disease
Milk Pasteurization (cow - tb)
it doesn’t kill all organisms, it only kills organisms which are pathogenic to us. started in 60s w/ tb outbreak in chicago. found it in mammary gland of infected cow. pasteuruzied became federal regulation. the spoilage microorganisms still survive (don’t harm us)
airborne pathogens (small, med, large)
aerosol particles can be small, small get dry quickly, then pathogen gets inactivated, and then they fall on the ground. The large size ones they fall to the ground immediately. the medium size they can stay and cause disease because the pathogen remains hydrated. farthest they can travel is 6 feet.
pathogens discharged as aerosols during
during sneezing, coughing or from air conditioning. aerosols are covered with water layer. coughing, sneezing, talking, yelling, etc.
droplets (aerosols) spread…
rapidly, remains airborne and are prone to be inhaled; difficult to control. medium size droplets are the ones that spread rapidly.
dust particles (hanta)
dust particles as in Hantavirus (causes Hantavirus pulmonary syndrome in humans). emains in top layer of soil. during hiking dust particles are prone to be inhaled along w/ the virus. will only be lethal if you’re immunocompromised. no harm if you’re healthy. outbreak at yosemite.
pathogen viability in air varies..(temps)
( dependent on humidity, temperature etc) if temp is high, aerosols dries up quickly, which will inactivate the virus. if temp is lower, water still hydrating the virus.
most biological warfare strategy uses..
uses aerosolized spores for maximal transfer effectiveness. spores in air and inhaled and germinate, then vegetative cells makes toxins. anthrax first choice.
Virus aerosol (IMCC)
IMCC
influenza, measles is the one that is contageous (easily transmitted), and chicken pox virus etc …chicken pox is only herpes that is aerosol transmitted. covid 19 pathogen.
Vectors
living organism that carry pathogen from one host to another- pathogen can be either internal or external on body surface-
Vector mediated transmission occurs by two general methods
mechanical and biological
Mechanical vector transmission (passive transmission) (toy)
passive on insect’s feet or other body parts; “brushed off” onto host - insect is NOT the natural host
Biological transmission (active transmission) (bite)
complex process, initiated via bite. can multiply within gut of insect. - spread requires insect consumes blood from several mammalian hosts
- pathogen multiplies in vector’s gut, migrate to salivary glands; injected directly into host following a bite - has to migrate to salivary gland because when it punctures the skin, the salivary glands contracts to introduce the salivary fluid. the fluid is introduced to prevent blood clot at the puncture site. it has anticoagulant in the saliva. with the saliva you get bacteria. vector serves as the host too
ex. of biological transmission PLZ DW
PLZDW
Dengue virus, West Nile, Plasmodium sps (causes malaria) transmitted by mosquito, zika virus. all transmitted by mosquitos. lyme disease.
food transmission - oysters
oysters are filter feeders - water treatment isn’t good, oysters will have norovirus in their bodies.
food transmission - beef
- beef can be tainted with normal microbiota or microflora ( E.coli O157: H7 secretes Shiga like toxin, toxic to kidneys )
Ex Bacterial aerosol (PPT)
pertussis, tuberculosis and pneumonic plague (aerosol transmitted) pathogen
mechanical vector ex. (toy)
house fly, cockroach, ant
vectors for biological transmission (bio-blood)
mosquitos, blood sucking flies, ticks, fleas, tse tse flies, sandflies
house fly - typhoid and dysentery, type of transmission -
mechanical. off the feces of infected peoples to food ants
formites are..
inanamate objects
direct transmission
It’s direct passage of infectious agent from one individual to another ( person to person spread ); no intermediate is involved - because often pathogen is very fragile. - includes of animal to human transmission
Direct transmission can also occur within the…
same individual - poor hygiene. UTI and e.coli. Also, includes pathogen transfer from mother to fetus (vertical transmission) via placenta. gonorrhea and syphilis, leads to neonatal gonorrhea or neonatal syphilis chicken pox (mother to fetus and cause congenital chicken pox)
Significance of transmission
important for pathogen survival
From animals via direct transmission (sheep) ex.
(inhalation, biting and scratching) rabies and anthrax (woolsorters disease)
Health care workers use gloves and gowns to prevent
direct contact - minimize this mode of transmission
Infectious agent’s indirect passage - what and ex. (waterfall- FVV)
FVV
from it’s fertile reservoir to an susceptible host. can be fomite mediated, vehicular and /or vector mode
Fomite
inanimate object that facilitates pathogen transfer to new host Ex : bed sheet, thermometer, toilet seat, toothbrush etc
Waterborne Transmission is common with…(drink)
gastrointestinal (oral, fecal route) pathogen - dispersal is mainly due to consumption of the large volume of water by the population.
ex. of waterborne GCC
giardia, cryptosporidium, both are protoza. water can transmit cholera pathogen.
ex. of transmission - direct contact
direct contact: touching :: cold virus, shaking hands kissing :: Epstein Barr virus ( herpes family) causes infectious mono
sexual intercourse :: HIV, HPV, herpes simplex ( HSV II) genital herpes
hanta virus replicates in..
kidneys and is shedded in urine.
animals that carry hanta
replicates in rodents and shed in urine
vector can also be the
host. mosquito
types of vectors (arturo)
Arthropods (invertebrates) are important vectors ; vertebrates too (cats, dogs, rodents - plague)
