Microbio Watkins, Exam 4,Viral and bacterial pathogens (4/4)

Measles

• Rubeola

• has vaccine available; in rare instances you can get it even when vaccinated

• airborne transmission → one of the most transmittable pathogen ever known

• can be transmitted even before even having symptoms

• can get meningitis as result (which can be deadly)

• 2019 → 12000 cases; going up due to some people not vaccinating children against it / fear mongering / vaccine debate; herd immunity decreasing

• 2025 → 700 cases so far

• in terms of death, worse than rubella

Symptoms of measles

• around 1 week after exposure → signs of raised rash

• can heal → complications arise when getting meningitis

MMR

vaccine for measles, mumps, rubella

symptoms of Rubella (german measles)

flat rash for about 3 days

German Measles

• Rubella

• “3 day measles”

• has a vaccine

• airborne transmission

• no US transmitted cases in over a decade (could change due to raising vaccine concerns from parents)

• congenital rubella syndrome - if a woman in the first 20 weeks of pregnancy (1st trimester), there a high likely hood of severe birth defects (microcephaly, cataracts, stillborn, etc.)

  • since most cellular development of the fetus is done in the first trimester

Herpes

• increasing connection to alzheimers / dementia

• “gift that keeps on giving” → will integrate into chromosomes and will be inside of the DNA permanently

  • tech being done to get ride of herpes with CRISPR

• rate of genital herpes in US: 12% males, 23% females

• HSV1 = tends to be more common in cases of oral herpes (can show up as genital herpes)

• HSV2 = tends to be more common in cases of genital herpes (can show up as oral herpes)

• first outbreak is the worse, then ones after are less severe

• potential / theoretical upside: immune system is in heightened state of alert on the lookout for pathogens and can go after pathogens faster, since it is constantly going after herpes pathogen; more protection against other pathogens

• can be transmittable for a certain amount of time, even outside of the body

oral herpes

• type of herpes

• virus resides in the trigeminal nerve

• herpes will survive in the nerve → move to the bottom of the nerve → release virus on surface of the skin in the force of sores

• will make a sinsitulism or multi nucleated cell

genital herpes

• can spread even when sores are not there

• lack of lesions does not equate to lack of virons (due to asymptomatic shedding - herpes virus still spreading)

• housed in the sacral nerve

condoms and herpes

• literature is skewed based on condoms protecting or not; ranges from 75% effective, 90% effective, 50% effective based on source used

• condoms are less protective against herpes than other diseases like HIV, this is because herpes is contained on the skin, while something like HIV is spread through bodily fluids

• some research says that women are more protected from males with herpes with condom usage, while males are less protected from female with herpes with condom usage

• are somewhat effective for herpes, but is not a guarantee

acyclovir / valtrex

an antiviral that an individual can take to reduce asymptomatic shedding of herpes; will reduce the risk of sexual partners contracting herpes

• will not be effective if the partner without herpes takes as a precaution / PEP

who would be of special concern with genital herpes

pregnant women; can result in neonatal herpes

• if giving birth vaginally while having a herpes outbreak, the mom can pass herpes to the child as the child passes through the birth canal

• in these cases, c-section is recommended

• not typical for the baby to contract herpes while in vitro, but it can happen

• if herpes gets into the central nervous system of a fetus, there is a 90% mortality rate

• if found, mom is given antivirals, with an increase in dosage closer to the due date

Are the cases of STDs going up

yes, dating apps make finding sexual partners easier than ever before; less energy is needed to procure a sexual partner; more sex = more transmission of STDs

HIV

• human immunodeficiency virus

• virus that can cause AIDS if left untreated

  • someone with HIV may never have AIDS

• became a problem around the late 70s - early 80s

• is more treatable and manegable today

• drugs to treat will go after reverse transcriptase (enzyme that makes RNA → DNA; integrates into genome)

• when still a newer known pathogen, transmission was unknown so there was a lot of fear

  • Ryan White was a hemopheliac and was given a blood transfusion that was HIV+, so he got HIV

  • blood was not tested for HIV in this time, since transmission was unknown

stigma of HIV

• still around even today

• a lot more in early 80s/ late 70s

• think back to Ryan White; was a student and there was protests to him going back to school since he got HIV from a blood transfusion; and transmission was unknown

• was mainly associated with homosexuals

• Rock Hudson, passed in the 60s due to complications associated with HIV but his real cause of death was kept secret to not tarnish his reputation

How does HIV work

• HIV will go after the CD 4 cell (helper T cells / white blood cells )

• helper T cells are critical in starting B cell and T cell response / immune response

• when CD4 cells are attacked, the immune response and immune system becomes weaker and weaker over time

• HIV will replicate within these helper T cells, thereby killing them

• fewer CD4 cells → less ability of immune system to fight off pathogens, cancers, etc.

  • t cells go after precancerous cells

  • less t cells → less effective defense and more opportunistic infections (like pnuemonia), illness lasts longer,

AIDS

• acquired immunodeficiency syndrome

• clinical determination that the patients has had HIV and the helper T cells (CD4 cells) number is at a lower level (allows for the presence of opportunistic infections)

HIV transmission

• most commonly seen within the MSM community, also seen with IV sharing/drug users

• shared through bodily fluids like semen and blood.

HIV symptoms

• first 1-2 years → immunity starts to go down; getting sicker than often with longer healing times; t cells slop downward

• after 1-2 years → medications can help stabilize t cells, must be consistent or will not work; can live a long life when managed; to low t cells means AIDS diagnosis

ART - antiretroviral therapy

• drugs used against HIV

• will target reverse transcriptase, which is a feature of retroviruses that uses RNA as a template to make DNA

  • will decrease the ability of HIV to duplicate

how can someone prevent HIV transmission

using PrEP and PEP

• PrEP → before exposure

• PEP → after exposure

PreP

pre exposure prophylaxis; medication that reduces the risk of HIV transmission to those without HIV (or other pathogens)

PEP

post exposure prophylaxis; vaccines or medications taken after HIV exposure to reduce the risk of getting HIV or other

Prevalance of Rabies

• US - rare in humans; 1-2 cases a year

  • most common in bats

• globally - 10,000-20,000 cases a year

  • most common in dogs

  • in the US, dogs are vaxed to prevent getting rabies

Rabies Vaccines

• a special request / case vaccine; will only receive if there is a reasonable risk of getting rabies

• will have a PEP (antibodies that will hopefully prevent rabies or full effect rabies)

  • PEP is recommended course or action if exposed instead of the vaccine

Symptoms of Rabies

• do not show straight away

• virus replicates in the muscle, then moves to the nervous system, and up the spinal cord to the brain, where neurological symptoms start (delirium, confusion, etc)

• treatment pre neuro. symptoms = high chance of not getting rabies

• treatment after neuro. symptoms =high chance of death

  • milwaukee protocol

    • “treatment” for rabies that has gone past the point of PEP / neuro. conditions started

    • person put into medically induced coma and pumped full of antibiotics / antivirals

    • sometimes work, normally doesnt

    • even when successful, neurological problems persist, with patients needing to relearn to talk, walk, eat, and function

transmission of rabies

via saliva; person is bitten and saliva enter bloodstream, eventually going to neurons and then the brain

• case where an individual had rabies and it was unknown. the person passed and their organs were donated. the patient who received the organs would get rabies and eventually pass away

when an animal is suspected to have rabies, what is done?

animal is quarantined and observed for symptoms, or the animal is euthanized and the brain is analyzed

Toxoplasma Gondii

• also called toxoplasmosis or taxo

• type of parasite that can be found in cat litter

• growing evidence infection can cause depression, BPD, and other neurological disorders

• explains why pregnant women are recommended to not change cat litter / avoid cats → can lead to miscarriage if exposed

H. pylori

• microaerophile that is linked to ulcers in the stomach

  • microaerophile - needs O2 at lower concentration than the atmosphere; atmosphere is 20% O2, while H. pylori needs 10%

  • linked to ulcers → stomach is very acidic and there is a layer of cells in the stomach to protect the muscle below + a mucous layer, these protect the stomach muscle from acid → bacterium eats away at the epithelium layer to house itself, the muscle is now exposed to the acid and will be ate away by the acid → causing ulcers

  • treated with proton pump inhibitor (reduced acid in the stomach) and antibiotic

• presence of H. pylori does not automatically mean ulcers

• testing → possible by breathing onto test strips from CVS / walgreens

how was H. pylori discovered?

• scientists kept seeing this bacterium in patients with ulcers, wanted  to see if the ulcers allowed the bacterium to grow, or if the bacterium caused the ulcers

  • Could not get human testers 

  • One of them drank a live culture of H. pylori and got ulcers and noble prize 

  • 90% of ulcers are the result of H. pylori 

TB - tuberculosis

• mycobacteria

• has a vaccine; but it is a special cases vaccine often given to healthcare workers

  • BCG vaccine

• also called “the consumption” since it would cause the body to waste away, and essentially consume the individual infected

transmission of TB

• airborne

• contagious, but not extremely; more than a few seconds/ minutes of contact is needed to contract it

how is TB tested for

• person injected with tuberculin; a subunit of TB

• if the immune system has seen the pathogen before, that area will swell up and become inflamed

• a positive test can also indicate vaccinations for TB in the past

  • further testing (xray of the lungs to look for calcification, a symptom of TB) can be done to prove or disprove a positive test

TB prevalance

• top of the list for historically significant pathogens

• cases have gone down

• not yet eradicated, but deaths are far less due to treatment options (antibiotics)

• first treatment of TB resulted in a nobel prize