BSCI223 Pak 3.3, Measles

In a period of three months, Fredrica has contracted three different diseases caused by Streptococci. Why did she not become immune to streptococcal infections after the first incident?

she probably got infected with more than one kindof streptococci.

What is the likelihood that she will get any of these infections again? Explain your answer in terms of the specific immune response.

she will be able to defend against streptococci strains with serotypes that her body is already familiar with, but won't be able to defend against strains with new serotypes

By taking a sample of pus from Fredrica's wound, Dr. Lecter was able to determine in less than 15 minutes that Fredrica was indeed suffering from a Group A strep infection. How does this rapid diagnostic test work? What does the rapid strep test have in common with home pregnancy tests? What is needed to provide these rapid tests with specificity?

The test contains antibodies against Group A strep antigens. If a color develops the sample contains group A antigens, and the pateint is infected with Group A strep. Antibodies and antigen interactions is what rapid tests have in common. The antibodies provide the specificity, as the only bind the antigen they recognize.

Antibiotics are effective at treating bacterial infections. Why is Dr. Chilton predicting that Earl will suffer from intestinal distress after taking ciprofloxicin?

•The antibiotics will disturb the normal flora

•Earl's alcoholism will mean reduced liver function

If one analyzes Earl's intestinal flora after Earl has taken ciprofloxicin, one would find that most of the isolates would be resistant to killing by this antibiotic. How could these organisms become resistant to these antibiotics?

•Use of antibiotics selects for antibiotic resistance

•Organisms acquire resistance to antibiotics through spontaneous mutation, or horizontal gene transfer.

Viruses

-obligate intracellular parasites (always have a negative outcome for host)

-ALL cells have ds DNA

-many other additional types of DNA/ RNA possibilities in viruses

Retroviruses

1. RNA into cell

2. RNA copied to DNA (reverse transcriptase)

3. DNA transcribed into RNA

-most famous retrovirus is the HIV virus

Virus evolutionary distance

-can't compare evolutionary distance because sm physiological, morphological, and genome variation b/w 2 viruses

Measles

-unsegmented (only 1 RNA molcule) negative RNA virus

-humans are ONLY reservoir

-90% susceptible individuals become infected

-no asymptomatic carriers

-cell types infected: epithelial, macrophages, b&t cells

-droplet transmission-ballistic/ parabolic trajectory when coughing

Measles timeline

1. exposure

2. 10-12 days after: general feeling of illness/ prodrome for 2-4 days (fever, runny nose, cough)

3. Mucous membrane rash

4. Skin rash ~2-4 days after prodrome (anorexia, diarrhea- dangerous for children)

5. Virus can be spread from days to years post exposure

-ssRNA virus

1. virus makes +ssRNA strand from -RNA template (now message can be transferred b/c can't make negative RNA from negative strand)

2. RNA is translated into -ssRNA

3. Packaged into new viruses

4. Virus escapes the cell

US Measles charts

-deceitful b/c number of cases isn't actually 0

Measles virus infection cycle

1. Measles gets into resp. tract

2. Affects epithelial cells

3. Macrophages come around

4. Measles affect phagocytosis and infects macrophage

5. Macrophages carry infected cells to lymph nodes

6. Measles virus comes out and infects b&t cells

If the B Cells become infected by measles virus, they will be killed by T killer cells after they express the endogenous viral antigens on the...

MHCI

US Measles incidence and death

-decline of measles death before vaccines b/c medical care and knowledge

-incidence rate lowered by vaccines b/c societal consequences (getting measles affects families)

Epidemic

disease occurs more often than it should

Endemic

disease regularly found in a location

Measles cases post 2000

All these cases have foreign origin from countries where its still endemic

-presumably eliminated in the US in 2000

VAERS

-Vaccine Adverse Event Reporting System

-lets people report adverse vaccine effects

VAERS clicker

inflammation

VICP

Vaccine Injury Compensation Program

-compensation to those injured by vaccines

-established after lawsuits threatened vaccine shortages

-stabilizes vaccine costs and ensure adequate vaccine supply

MMR vaccine and autism

-claimed all children were previously normal, but 5 had previous concerns

-only 1 child had autism

Thimerosal and autism

-thimerosal used to stabilize vaccines

-not associated with any ASD outcomes in girls or boys

Danish Autism Cohort Study

.95% of vaccinated children had autism

and 1.66% of unvaccinated, but there are more vaccinated children w/ autism b/c larger population