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85 Cards in this Set
- Front
- Back
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Influenza viruses are made out of... |
RNA |
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What is the family of the Influenza viruses called? |
Orthomyxoviridae |
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What are the different viruses? |
A, B, and C |
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What are the Outer Surface Proteins? |
Hemagglutinin (HA) protein and Neuraminidase (NA) protein |
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What is the incubation period? |
1 to 4 days with an average of 2 days |
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What does virus shedding begin? |
About 12 hours post exposure |
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When does virus shedding peak? |
Day 2 |
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How long does virus shedding continue? |
9 days |
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How long do children shed the virus for? |
2 weeks |
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When can people be infectious? |
1-3 days prior to symptom onset and a week after symptoms dissipate |
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List the 3 ways in which it is spread. |
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How is the virus spread directly? |
sneezing of infected mucus directly into eyes, nose or mouth |
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How is the virus spread through the air? |
the inhalation of aerosols produced by coughing, sneezing, and spitting |
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Can a hand shake transmit the virus? |
Yes |
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How long can the virus survive outside the body? |
Days to weeks depending on conditions |
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How long can the virus survive on hard surfaces? |
1-2 days |
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How long can a virus survive if it is on a surface with mucus? |
17 days |
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A virus can persist in air if... |
given high humidity and low UV radiation |
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What fraction of people are asymptomatic? |
1/3rd |
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When do most symptoms appear? |
1-4 days post exposure |
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What would the fever usually be? |
100 to 103 degrees |
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Extreme coldness with... |
shivering, shaking, and rigor |
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Aches and pains are greatest in the... |
back and legs |
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Common Symptoms (6 of them) |
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Typical complications include... |
viral and bacterial pneumonia |
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What is basic prevention? |
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What clothing may help? |
Surgical mask |
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What should you sanitize surfaces with? |
alcohol or diluted chlorine bleach |
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How often should you vaccinate? |
Yearly |
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What should you do during a pandemic? |
close schools, avoid public gatherings, theaters and churches, and public transportation |
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The first influenza symptoms were described when and by whom? |
2,400 years ago by Hippocrates |
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Columbus visited the Antilles and... |
the entire population died of a flu-like epidemic |
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How many people did the Asiatic flu kill? |
About 1 million |
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How many did the Spanish Influenza kill? |
About 100 million |
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How many did the Asian Influenza kill? |
1.5 million |
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How many did the Hong Kong Influenza kill? |
1 million |
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How many did the Swine Influenza kill? |
About 400 thousand |
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The 1918 Influenza Pandemic was created by... |
the H1N1 virus |
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The 1918 Influenza Pandemic killed what percent of the world's population? |
5% |
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How many people did the 1918 Influenza Pandemic infect worldwide? |
500 million |
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How far reaching was the 1918 Influenza Pandemic infection? |
Stretched to remote islands in the Pacific all the way to the Artic |
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The 1918 Influenza Pandemic primarily killed... |
healthy young people |
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The 1918 Influenza pandemic created a in its infected. |
cytokine storm |
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What was the infection rate of the 1918 Influenza Pandemic? |
50% |
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What was the mortality rate of the 1918 Influenza Pandemic? |
20% |
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How did the 1918 Influenza Pandemic spread? |
Through WW1 troop movement and increased international travel |
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In 1918 the law required the use of... |
surgical masks |
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Serotype |
difference in surface antigens within the same species |
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Strain |
small variations in genome within the same species – antigenic drift |
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Subtypes |
larger variations in the surface proteins (antigens) within the same species – antigenic shift |
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Subspecies |
variants geographically isolated within the same species |
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Influenza B infects... |
humans, seals, and ferrets |
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Why is Influenza B not genetically diverse? |
Has a slow mutation rate with only 1 serotype |
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When do people develop immunity to Influenza B? |
When they are young |
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Can Influenza B cause illness? |
Yes but only with very mild symptoms |
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Has Influenza B ever caused a pandemic/epidemic? |
No |
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Can Influenza C create illness? |
Yes but only with very mild symptoms |
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What can Influenza C infect? |
Dogs, pigs, and humans |
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Has Influenza C ever created a pandemic/epidemic? |
No |
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What can Influenza A infect? |
Humans, pigs, horses, seals, whales, but mostly BIRDS |
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How many serotypes are in Haemagglutinin? |
15 |
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How many serotypes are in Neuraminidase? |
9 |
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What does Haemagglutinin cause? |
red blood cells to clump together binding the virus to the cell |
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What does Neuraminidase help? |
aids in movement of the virus through the infected cell and in budding from host cell |
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How are Influenza A viruses named? |
After their HA and NA serotypes combined |
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What are the least fatal types of Influenza A? |
Types that affect the nose, mouth and trachea |
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What are the most fatal types of Influenza A? |
Types that affect the lungs |
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What is an Antigenic Drift? |
mutations which create a slight change in the binding sites that the virus uses to attach to host cells |
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What does an Antigenic Drift do? |
creates a new viral strain |
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Can a strain created by an Antigenic Drift still be recognized by antibodies? |
May or may not depending on the change. Some antibodies may still recognize it. |
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Is Antigenic Shift or Drift the reason that people need to be vaccinated yearly? |
Antigenic Drift |
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What do Antigenic Drift viruses cause in a previously infected person? |
A mild flu |
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What is an Antigenic Shift? |
A rare event involving an abrupt major change in the virus. |
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How does an Antigenic Shift occur? |
Two serotypes swap or re-assort genetic material |
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Why do immune systems not recognize Antigenic Shift viruses? |
A new virus with unknown outer surface proteins is created |
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What do Antigenic Shift viruses cause? |
Severe infections that cause pandemics |
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What Influenza type can be changed through Antigenic Shifts? |
Influenza A |
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How often do Antigenic Shifts cause pandemics? |
Every 10-50 years |
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What is reassortment? |
Swapping of genetic material |
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Reassortment has caused... |
all of our past pandemics |
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What does cytokine signal? |
the immune cells to go to the site of infection |
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How does cytokine signal for more cytokine to be created? |
A feedback loop |
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What can a new pathogen do to the cytokine response? |
Cause it to become exaggerated |
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Why is it bad when the cytokine storm happens in the lungs? |
The lungs fill with fluids full of immune cells |
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What type of people usually die from cytokine storms? |
Young healthy people |
