6.5 other pathogenic agents

Question 1

what is an example of a virus as a pathogen?

Answer 1

the influenza virus

Question 2

how is the influenza virus transmitted?

Answer 2

• droplet infection
• contact with animal droppings or virus filled mucus from the nose
• toutching contaminated surfaces
• zoonotic infection (animals)

Question 3

what is the mode of infection for the influenza virus?

Answer 3

• infects ciliated epithilial cells of the respiratory system
• injects viral RNA
• viral RNA takes over the biochemistry of the cells
• cells produce new virus particles
• lysis and release of new virus cells
• damaged epilthilial cells makes you more prone to new infections

Question 4

what are the pathogenic effects of the influenza virus?

Answer 4

• fever
• shivering
• sweating
• aching joints
• shortness of breath
• lasts 5-7 days and if you get a secondary infection you can’t fight it

Question 5

what are the treatments and how do we control the influenza virus?

Answer 5

• no cure
• rest
• get vaccinated

Question 6

what is an example of a fungus as a pathogen?

Answer 6

the stem rust fungus of cereal crops

Question 7

how is the stem rust fungus of cereal crops transmitted?

Answer 7

• spores carried in the wind
• if parts of infected plants are left in the soil

Question 8

what is the mode of infection of the stem rust fungus of cereal crops?

Answer 8

• hypha emerges from a spore and penetrates the stomata
• this secretes enzymes such as cellulase which digests plant cells and nutrients are absorbed
• hypha forms a mycellium that feeds and grows

Question 9

what are the pathogenic effects of the stem rust fungus of cereal crops?

Answer 9

• absorbs nutrients from a plant
• difficult to transpire
• absorbs water
• weakens stems of plants so they fall over

Question 10

how can we control the stem rust fungus of cereal crops?

Answer 10

• allow for bigger spaces between fields
• use less pesticides
• use earlier maturing crops
• remove the virus crops

Question 11

what is an example of a protozoa as a pathogen?

Answer 11

Plasmodium spp. (Malaria)

Question 12

how is malaria transmitted?

Answer 12

• through the vector of the female mosquito when she feeds

Question 13

what is the mode of infection of malaria?

Answer 13

• malaria paracite travels to the liver
• released into blood and infects red blood cells
• reproduces asexually and bursts out of red blood cells (lysis)

Question 14

what are the pathogenic effects of malaria?

Answer 14

• lysis causes: fever, sweating, shaking, muscle pains and headaches

Question 15

what are the treatments and method of control for malaria?

Answer 15

mosquito nets, pesticides, insect repellant, vaccines, avoiding standing water and antimalarial tablets –> preventative measures

Question 16

what are issues with treatment and control of malaria?

Answer 16

• ethical: difficulty obtaining informed consent, insecticides affect other organisms
• social: changing customs
• economic: very expensive
• practical: endemic to many countries