2. Microorganisms that cause diseases are
classified as pathogens.
And pathogens can be divided into 3
categories.
3. (a)Bacteria and protozoa which produce toxic
chemicals that kill their host cells.
(b)Viruses which enter and destroy their host
cells.
(c)Fungi which produce enzymes that
decompose the tissues of the host.
36. H1N1, which caused Spanish Flu in 1918, and Swine
Flu in 2009
H2N2, which caused Asian Flu in 1957
H3N2, which caused Hong Kong Flu in 1968
H5N1, which caused Bird Flu in 2004
H7N7, which has unusual zoonotic potential
H1N2, endemic in humans, pigs and birds
37. Name of
pandemic
Date Deaths
Case fatality
rate
Subtype
involved
Pandemic
Severity Index
Asiatic
(Russian) Flu
1889–1890 1 million 0.15% possibly H3N8 NA
1918 flu
pandemic
(Spanish
flu)[168]
1918–1920
20 to 100
million
2% H1N1 5
Asian Flu 1957–1958 1 to 1.5 million 0.13% H2N2 2
Hong Kong Flu 1968–1969
0.75 to 1
million
<0.1% H3N2 2
2009 flu
pandemic[169] 2009–2010 18,000 0.03% H1N1 NA
56. Some pathogens are transmitted through tiny
droplets of moisture.
When an infected person sneezes/ cough,
pathogens are released into the air and infect
other person who breath in.
Diseases that are spread like this are influenza
and tuberculosis.
57. Some pathogens lives in water such as ponds,
rivers and the sea.
Some pathogens are spread into water
supplies due to insanity condition.
Diseases that are spread like this are
dysentery and Hepatitis A.
58. Food that is not cooked or handled properly
may be contaminated.
Pathogens may come from surrounding or
faeces.
Diseases that are spread like this are cholera
and food poisoning.
59. Direct contact, sexual contact and sharing of
personal belongings such as comb, towels and
needles can spread diseases.
Diseases that are spread like this are ringworm
and AIDS.
60. Vectors are organisms that carry pathogens
that cause them to contract diseases.
Some of the examples of vectors are
mosquitoes, houseflies, cockroaches and rats.
For example, dengue fever is spread when the
saliva of the mosquito enter the body.
