entry and exit transmission (7)

which receptor molecules do HIV and EBV need to attach

HIV - CD4 and CCR5

EBV - C3d

what 2 compounds are on skin that make it acidic

fatty acids and sebaceous gland secretions

how does someone get conjunctiva

from micro-abrasions like when u scratch your eye

4 defences in the eye

flushing with tears, lysozyme, IgA, transferrin (takes up Fe not letting bacteria get it)

2 ways bacteria avoid cleansing in the respiratory tract

attach by adhesins to cell surface receptors on epithelial cells

inhibit ciliary action

what are 5 defences in the oropharynx (right behind the mouth)

flushing of saliva, chewing and other activities in the mouth, IgA, lysozyme, antimicrobials in saliva

what do bacteria (good and bad) need to do to stay in the mouth and avoid all of our defences

attach to mucous and or teeth surfaces

how does someone get candida

after you take BS antibiotics, there is an imbalance in the flora

what are the defence mechanisms in the gastrointestinal tract

peristalsis and mucus

what does vibrio cholera do

opens epithelial cells so the person leaks ions and liquids, and produces mucinase which degrades the viscosity of the stomach mucus

what does H. pylori do

produces urease which degrades stomach mucus

which bacteria do you get in ur vagina over reproductive years

Lactobacilli which lowers pH by taking glucose → lactic acid

2 defences of the urethra

flushing of urine and mucous layer with IgA

why are women more prone to urogenital tract infections than men

distance between urethra and anus in women is way less than men

mechanisms of urogenital tract invasions

attachment for parasite-directed endocytosis (parasite tricks a host in engulfing it), intestinal bacteria entering urethra, foreskin (moist)/STI

3 factors affecting transmission

number of pathogens shed (from sneezing or coughing or diarrhea)

stability in the environment (eg heat or pH)

efficiency of infection (ID50 → lower the number, more infectious)

examples of typhoid vs typhus

typhoid - salmonella

typhus - riketsia

3 transmission mechanisms for yersinia pestis and what they lead to

fleas → rats → bubonic plague (left untreated can cause septicemic plague)

fleas inject directly into blood from cut → septicemic plague

human → human by cough → pneumonic plague

where is trypanosoma found and what is the insect that transmits it

in South America it is the kissing bug

in Africa its the tsetse fly

T/F antigenic shift is in both RNA and DNA viruses

false, only in DNA (not even segmented) because DNA pol is too efficient

difference between vertical and horizontal transmission

horizontal - pass to non-related people

vertical - pass to progeny either through genetics, placenta, or bacteria present in the vagina during vaginal birth

why was cholera and typhoid super common in England 200 years ago

terrible sewage filtration so they were drinking sewage water, found most cases were in close proximity to contaminated wells

T/F cholera and typhoid dont exist in developed countries because we have good water filtration

false, it is just now spread by food and fingers

how can you tell if herpes is not sex-related

warts (type 1 and 2) are not sex related

most common bacterial STIs in canada from most to least common

chlamidya, gonorrhoea, syphillus

most common viral STIs in Canada from most to least common

Herpes, HPV, hep C, hep B, HIV 5

what will be a doctor’s response when a pregnant woman has HIV or gonorrhoea

baby should be born C section to avoid the bacterium in the vagina, and be given anti-virals/microbials

3 STIs present in semen

cytomegalovirus, HBV, HIV

what is transmitted through human milk

HIV, CMV, HTLV-1 (can cause leukaemia)

difference between toxocariasis and toxoplasmosis

toxocariasis comes from dogs, plasmosis from cats (tm through placenta so pregnant mom shouldn’t clean litter box)

was covid antigenic shift

NO because it was carried by bats so zoonotic spillover

2 ways urban areas transmit from animals

eating infected animal products, or occupational like butchers and farmers