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Lecture 7

Lecture 7 Study Guide

7 Pages
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Department
Environmental Science
Course Code
EESA10H3
Professor
Jovan Stefanovic

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EESA10 Lecture 7
Biological Hazards and Human Health
This lecture overlaps with next lecture on “Food and Food borne Diseases, because they
both have same agents, bacteria, viruses. These can be considered as biological hazards
but also they can found in food substances, and cause food borne hazards.
Biological Hazards
Biological Hazards can be nontransmissible (cannot be transferred from one human to
another human). Examples of such nontransmissible diseases include: cardiovascular,
cancer, diabetes, asthma. What are cardiovascular diseases? These are diseases related to
heart as a result of food (high cholesterol), lack of exercise, lots of stress, smoking, etc.
Cancer has many different causes (we cannot specify just one cause for it). Every cancer
is caused with many different agents (environmental, genetical, etc.). There is no strong
proof that these diseases can be transferred from human to human. Diabetes can be
caused because of genetics, food, and obesity. There is no strong evidence that diabetes
can be transferred from human to human. Asthma is closely related with some allergens
(something in our environment). Everyday many new agents and chemicals and applied
to us, and they may cause asthma. There is no proof that asthma can be transmitted from
human to human.
Transmissible diseases: Diseases caused by bacteria, viruses, or protozoa can be certainly
transferred from humans to humans. Bacteria can be cured using anti-biotics. Anti-biotics
are medicine that we take if we have bacterial infections. However, Anti-biotics do not
work with viral infections. For example, doctors will not prescribe anti-biotics if you
have flu, or some other kind of viral infection. If you take anti-biotics for any viral
infection or any other infection, you will be overusing anti-biotics (using anti-biotics
when we do not need it, or not prescribed by the doctor, or taking anti-biotics more
frequently for not very serious disease). What will happen as a result? This can lead to
very significant resistance of bacteria to these anti-biotics. Next time, if someone is really
serious, and needs anti-biotics, those anti-biotics will not work. This is because growing
germ produces resistance to antibiotics. How do the bacterias develop resistance? This is
because they are growing very fast. They reproduce very quickly. Also, they very quickly
transfer that mutation (that adjustment) to the next generation. This process goes through
generation to generation very quickly, much faster than any other organism on the planet
can do (High reproductive rate allow them to become genetically resistant quickly). One
more reason why bacterias grow resistance to anti-biotics is because of the use of
antibiotics in food additives to boost livestock. Veterinarians, agriculture specialists,
farmers, they all use antibiotics to prevent diseases in animals. Farmers use antibiotics to
prevent disease from happening, and if we consume that kind of meat (with high
concentration of anti-biotics), we might become more resistant to antibiotics.
Biological Hazards
Bacterial Diseases
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1) Tuberculosis: When we talk about this disease, we always think about the past (before
World War 2, before discovery of antibiotics). This was a big problem. However, it
seems that this is not the case. Even today, it is a significant threat to humans. But indeed,
this is a very old disease. Scientists found evidence that mummies from Egyptian era had
symptoms of tuberculosis. This was a very big problem during 18th, 19th, and beginning of
20th centuries. This disease used to run in families, as it was transferred from one family
member to another member of the family, very easily. For example, back then, when
someone wants to marry someone, they used to look at what family is the bride or groom
coming from, does that family have tuberculosis. This is how disease was transferred
from one family to another. During 18th and 19th centuries, this disease was related to
vampires. This is because sick people from this disease were very pale face, they had
watery bloody eyes, and they sometimes spit blood (cough a lot). That time no one knew
what tuberculosis was, and people connected these symptoms with vampires. Later on,
humans found out the truth, but they could not find any cure, until the discovery of
antibiotics. After this discovery, most of the cases (but not all) of tuberculosis were
cured. These agents mutate easily, and they change very quickly. This can cause different
types of tuberculosis. Most of these kinds of tuberculosis are very resistant to known
tuberculosis, which makes it hard to cure. Therefore, they are a threat even today. Some
statistics: In 2004, mortality statistics included 14.6 million chronic active TB cases, 8.9
million new cases, 1.6 million deaths, mostly in developing countries. What does chronic
active mean? If individual comes in contact with an agent (with this bacteria), that person
does not get ill right away. For very long time, that person may not show any symptom of
this disease. Active means visible symptoms. Chronic means for a long time. Why is it
mostly in developing countries? This disease, in the past and even today, is a socially
related disease. Poor people with not adequate supply of food, bad housing, wet walls,
unsafe conditions, these get sick more easily because their immune system is reduced
(lower) and they catch this disease faster. This disease is always related with social
factor. In developing countries, their health system is not very organized, not all people
have access to proper health. This adds to one of the reasons for tuberculosis. How can
this disease be transferred from person to person? Transmission - cough, sneeze, speak,
kiss, or spit of ill person, breathing (basically, any direct contact). This disease most
commonly attacks the lungs (through the breathing of the agent). This bacterium is
sensitive to UV radiation and oxygen. These were the only ways how people prevented
them in the past. They took all clothes, mattress, or anything that came in contact with the
ill person (almost 100 years ago), were exposed to the sun and oxygen for long periods of
time, because they realized that sun helps. Symptoms include chest pain, coughing up
blood, and a productive, prolonged cough for more than three weeks, fever, chills, night
sweats, appetite loss, weight loss, paleness and often a tendency to fatigue very easily.
Tuberculosis- a growing threat
Problem in Africa (mostly southern Africa), South America, Asia. Not a problem in
North America, Australia. If you want to travel in tuberculosis affected countries, you
have to get a vaccine.
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Description
EESA10 Lecture 7 Biological Hazards and Human Health This lecture overlaps with next lecture on Food and Food borne Diseases, because they both have same agents, bacteria, viruses. These can be considered as biological hazards but also they can found in food substances, and cause food borne hazards. Biological Hazards Biological Hazards can be nontransmissible (cannot be transferred from one human to another human). Examples of such nontransmissible diseases include: cardiovascular, cancer, diabetes, asthma. What are cardiovascular diseases? These are diseases related to heart as a result of food (high cholesterol), lack of exercise, lots of stress, smoking, etc. Cancer has many different causes (we cannot specify just one cause for it). Every cancer is caused with many different agents (environmental, genetical, etc.). There is no strong proof that these diseases can be transferred from human to human. Diabetes can be caused because of genetics, food, and obesity. There is no strong evidence that diabetes can be transferred from human to human. Asthma is closely related with some allergens (something in our environment). Everyday many new agents and chemicals and applied to us, and they may cause asthma. There is no proof that asthma can be transmitted from human to human. Transmissible diseases: Diseases caused by bacteria, viruses, or protozoa can be certainly transferred from humans to humans. Bacteria can be cured using anti-biotics. Anti-biotics are medicine that we take if we have bacterial infections. However, Anti-biotics do not work with viral infections. For example, doctors will not prescribe anti-biotics if you have flu, or some other kind of viral infection. If you take anti-biotics for any viral infection or any other infection, you will be overusing anti-biotics (using anti-biotics when we do not need it, or not prescribed by the doctor, or taking anti-biotics more frequently for not very serious disease). What will happen as a result? This can lead to very significant resistance of bacteria to these anti-biotics. Next time, if someone is really serious, and needs anti-biotics, those anti-biotics will not work. This is because growing germ produces resistance to antibiotics. How do the bacterias develop resistance? This is because they are growing very fast. They reproduce very quickly. Also, they very quickly transfer that mutation (that adjustment) to the next generation. This process goes through generation to generation very quickly, much faster than any other organism on the planet can do (High reproductive rate allow them to become genetically resistant quickly). One more reason why bacterias grow resistance to anti-biotics is because of the use of antibiotics in food additives to boost livestock. Veterinarians, agriculture specialists, farmers, they all use antibiotics to prevent diseases in animals. Farmers use antibiotics to prevent disease from happening, and if we consume that kind of meat (with high concentration of anti-biotics), we might become more resistant to antibiotics. Biological Hazards Bacterial Diseases www.notesolution.com
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