Immunology Chapter 1

Front 1

What is immunology and the reason for the term?

Back 1

Immunology is the study of how the body responds to and resists pathogens and other foreign substances. It comes from 'immunis', which is latin for exempt because classical scholars noted that persons infected with specific infectious diseases were not re-infected.

Front 2

What is smallpox? How does it spread? What causes it?

Back 2

Small pox is a moderately infectious disease meaning 'spotted' in latin, in reference to a rash. It is spread by the respiratory route and fomites.It is caused by variola major and rarely by the less virulent variola minor (both lack non-human reservoirs).

Front 3

Why is smallpox likely the most significant disease in history?

Back 3

There were periodic outbreaks throughout history in the old world, it nearly eliminated the Native Americans, it killed 60-90% of Incas when Cortes introduced it in 1520, and it may have been the first case of biological warfare. Frequent outbreaks of smallpox in Britain led to the establishment of U.S. universities.

Front 4

What are the symptoms and outcome of smallpox?

Back 4

30% fatality rate if untreated (1% if variola minor), "pock marked" scars, ulcerations of the cornea that can cause blindness.

Front 5

How do you know if you have smallpox?

Back 5

7-17 asymptomatic incubation, 4 days fever and vomiting (major)(this prodrome stage is non-infectious), 5 day pustule/rash formation (very infections), the either death due to secondary infections or fluid loss or 5 days where scabs form, fall off and leave scarring.

Front 6

Describe smallpox scars.

Back 6

They feel like a BB under the skin. They are first in the mouth, then arms and hands. Pustules are depressed in the center and filled with pus.

Front 7

How can you differentiate between smallpox and chickenpox?

Back 7

Smallpox pustules are depressed in the center, hard, all in the same stage, and on hands and feet (centripetal). Chickenpox lesions are superficial, occur in crops, have different sizes, and appear on the trunk (centripetal). The course of smallpox takes approx. 25 days while chickenpox takes only 10.

Front 8

What is variolation? What are some problems with it?

Back 8

Variolation is infecting someone with a low dose in an abnormal delivery site. Example: Grinding up smallpox scabs and infecting someone on the skin. It is effective, and started by the chinese. Lady Montague brought it into the aristocracy. Howeer, it is highly variable, can cause fatalities, can cause skin lesions, and the variolated are still infectious.

Front 9

What is vaccination?

Back 9

Vaccination uses an different attenuated (weakened) strain of an organism to confer immunity. This was started by infecting people with cowpox (vaccinia) to become immune to smallpox. Natural smallpox was thus eliminated in 1977. There are no non-human reservoirs, so this means that if can be vaccinated out of existence. However, a few sites have smallpox cultures and it could be reconstructed using genomic info, so there is a new smallpox vaccine because of concern about bioterrorism.

Front 10

What is attenuation?

Back 10

Attenuation is the 'gold standard' for vaccination. A viable pathogen is weakened so that it remains infectious, but not pathogenic (does not induce pathology). This triggers a strong adaptive immune response. This can be done using heat, serial passage in eggs, passage in cell culture or on plates, and genetic engineering (the last 3 of which all involve genetic manipulation). However, it is very important that the person already have a functional immune response. People with AIDS can die from this because pathogens revert to wild type.

Front 11

What are some other examples related to attenuation?

Back 11

Anthrax and Rabies. Rabies was the first human use of an attenuated vaccine.

Front 12

Which diseases have been irradicated by vaccines? Which are close but increasing because there is not the same degree of vaccine coverage today?

Back 12

Smallpox, diphtheria, and paralytic polio have been irradicated. Measles, mumps, pertussis, rubella, tetnus and invasive hemophilus influenzae are on the rise.

Front 13

What is polio?

Back 13

Polio (also infectious infantile paralysis) is a virus spread via the fecal oral route. In a majority of infections, nothing happens (sub-clinical), but some develop paralytic polio requiring treatment with the iron lung, leading to respiratory failure. Hygiene is implicated in the 1950s surge because disease severity increases with age.

Front 14

There were two vaccines for polio. Salk's (dead injected) then Sabin's (oral attenuated). Why did the WHO switch back to Salk's in 1999?

Back 14

Because of the fear of reversion.

Front 15

What are the benefits of vaccines?

Back 15

Few or no side effects, specific effects, little resistance, usually prevent disease (rather than treat), herd immunity, can eradicate some diseases and (relatively) cheap.

Front 16

What is DPT?

Back 16

Diptheria-Pertussis-Tetnus shots

Front 17

What is tetnus and how is it treated?

Back 17

It is caused by the ubiquitous soil bacterium clostridium tetani and is introduced via puncture wounds (and soil on the unbilical stump of unvaccinated mothers and IV drug users). It causes 'lock jaw' where all the skeletal muscles contract and 3-4 weeks paralysis (if you survive). It can be treated with an anti-toxin, muscle relaxants and tracheostomy and mechanical ventilation.