Class Notes (1,100,000)
CA (620,000)
UTSC (30,000)
HLTB21H3 (200)
Lecture

HLTB21H3 Lecture Notes - 1918 Flu Pandemic, Aids, Influenza A Virus Subtype H2N2


Department
Health Studies
Course Code
HLTB21H3
Professor
Caroline Barakat

This preview shows page 1. to view the full 5 pages of the document.
Lecture 10: Influenza/HIV-AIDS
Influenza History
Can be dangerous (became pandemics)
Hippocrates - record of an influenza pandemic in the year 412 B.C.
Since 1580, there have been thirty-one additional flu pandemics recorded
Spanish Flu (1918 - 1919) b/c Spain did not provide any censorship of how many cases and
people were affected.
Not only affected soldiers, but civilians as well
Approximately 50 M deaths worldwide in less than 2 years (1918-1919)
500,000 death in the US (19,000 in New York City)
300,000 cases in Ontario - 8700 death (1200 deaths in Toronto in just 3 weeks)
500,000 cases and 14,000 deaths in Quebec
Video:
Spanish flu:
Cause by virus
20 million people died (more than the first world war)
If there wasn’t war, strain would have be kept isolated
Originated from US who made their way to France and other countries trading materials as well
as the flu
It took 17 days to spread
Wearing face masks, carrying garlic and onion to help prevent it, but they left their nose
exposed where they were most likely to catch it
Symptoms
High fever, chills, headache, weakness and fatigue as well as coughing, sneezing, runny nose
regular cough but it is different because these symptoms come suddenly
Residual cough and tiredness, depression lasts up to 6 weeks
Complications can include ear infections, pneumonia, dehydration and death
Etiology
3 types of influenza virus: Influenzavirus A (most virulent), B, &C
Influenza A and C infect multiple species (a and c can mixed together and form a new virus),
while influenza B almost exclusively infects humans (b and c sporadic and affects young children
and old)
Influenza A virus has 8 genes
o Because there is constant mixing/mutation in different species
New and virulent flu strains are produced mainly from the effects of two surface
proteins
Hemagglutinin (H) critical to virus entry into cell
Neuraminidase (N) allows virus to leave host cell after replication and move from cell to cell
There are over 15 H’s and 9 different N’s in bird flu viruses (don’t cause harm and are excreted
through feces, but whoever comes across the feces will become infected in domestic birds and
give it to humans)
Flu virus from birds - unable to replicate well in humans unless they move to an intermediate
host: chickens, geese, ducks
Flu genes of birds, pigs, humans can mix and produces new strains
We know that flu virus is contagious :A10 (Can infect 10 people) rnot is 10
Pandemics occurs 2-3 time per century
You're Reading a Preview

Unlock to view full version

Only page 1 are available for preview. Some parts have been intentionally blurred.

Before one wave of influenza is done, another kind can come again (hard to find a vaccine
because it mutates)
Antigenic drift
Random mutations that change the genes causing the virus to change
The genetic composition of the new strain is mixed with genes of avian strain and human strain
Epidemiology
Occurs globally, year-round (more temperate areas (colder climates), where it is more enclosed
with less ventilation
Serotypes that have been confirmed in humans (ordered by the number of known human
pandemic deaths):
o H1N1 - ‘Spanish Flu’ (refer to end of 2nd paragraph, p. 398 of course
textbook)doesn’t mean that this is the same H1N1 as now because there isn’t the
same amount of damage
o H2N2 - ‘Asian Flu
o H3N2 - ‘Hong Kong Flu’
o H5N1 - pandemic threat in 20078 flu season
o H7N7
o H1N2 - endemic in humans and pigs
o H9N2, H7N2, H7N3, H10N7
o Happens in Asia more often because humans come in contact with their domesticated
animals more than other countries
Video:
Spanish flue the same as H1N1?
This strain is different from spanish flu
Spanish had specific destinations
The name is just a technical name and has the same number of H and N
Mode of Transmission
Respiratory Droplets - contain the virus and are expelled into the air by coughing, sneezing or
talking and enter the body through a person’s mucous membranes (e.g., nose, mouth).
Direct Contact the virus spreads from person-to-person from the hands of an infected person.
A person touches their mucous membranes with their contaminated hands.
Indirect Contact - The virus spreads from one person to another by touching surfaces or objects
contaminated with the virus. A person touches their mucous membranes with their
contaminated hands.
Flu shot is encouraged, but only protects from the strains that are targeted
Some vaccine shows symptoms, but it really protects the elder
HIV/AIDS
In late 70s there was increase rate of homosexual diseases and some sort of pneumonia that
turned into HIV
HIV (Human Immunodeficiency Virus) - attacks the immune system resulting in chronic,
progressive illness that leaves people vulnerable to opportunistic infections and cancers
Results in AIDS (Acquired Immunodeficiency Syndrome) when the body can no longer fight
infection due to HIV
On average, it takes more than 10 years for the disease to progress from HIV infection to AIDS
AIDS was first reported in the US in 1981, a related virus HIV II was described in 1985
You're Reading a Preview

Unlock to view full version