other pathogenic agents

Question 1

define endemic and epidemic

Answer 1

endemic - disease occurs routinely in a geographical area
epidemic - temporary rapid increase in incidence of disease in a geographical area

Question 2

what is a influenza infection ?

Answer 2

a virus attaches to a cell surface protein to enter a cell
infects tissues of the breathing system , esp the lungs

Question 3

how is influenza virus transmitted ?

Answer 3

• droplet infection
• direct contact with animal droppings
• direct contact with virus filled mucus
• direct contact from surfaces contaminated with virus

Question 4

outline the mode of infection of influenza ?

Answer 4

1. infects ciliated epithelial cells of the lungs
2. Viral RNA takes over biochemistry
3. Cell produces new virus particles
4. Cell lyses
5. Many viral particles are released and dies

Question 5

what pathogenic effects does the influenza virus have ?

Answer 5

lysis of cells and release of toxins cause coughing, headache, vomiting and other symptoms

Question 6

how is influenza treated?

Answer 6

antiviral medication
antibiotics treat secondary bacterial infection
management of symptoms

Question 7

how is stem rust fungus transmitted ?

Answer 7

• wind carries spores from infected plants
• infected plant fragments in soil

Question 8

outline the mode of infection of stem ruse fungus

Answer 8

• spores germinate in water on plant
• hyphae enter through stomate of the leaves
• enzymes, cellulose, digest the plants cells
• nutrients are then absorbed into the fungus

Question 9

what pathogenic effects does stem rust fungus have ?

Answer 9

• nutrients lost to the fungus
• steam weakened and may collapse in the wind
• pustules appear through leaf epidermis
• plant loses control over water loss

Question 10

name the malarial parasite ?

Answer 10

plasmodium spp.

Question 11

outline the mode of transmission and infection of the plasmodium spp parasite

Answer 11

1. malarial parasite transmitted to person from infected anopheles mosquito
2. parasites travel to the liver
3. released from liver into the blood where they invade the red blood cells
4. parasites reproduce asexually and burst out of red blood cells, destroying them
5. malarial parasite transmitted to mosquito taking a blood meal - more life cycle stages before transmitting to another person

Question 12

what are the pathogenic effects of malaria ?

Answer 12

• burst out of red blood cells every 2-3 days causing fever, sweating , shaking , muscle pains and headaches
• liver damage and anaemia may eventually lead to death

Question 13

how is endemic malaria controlled ?

Answer 13

• preventing mosquito bites: mosquito nets, insect repellent
• controlling mosquito numbers: pesticide, chemical treatment of standing water and sewage
• drug treatment

Question 14

suggest the ethical and social implications controlling endemic malaria ?

Answer 14

• treatments must be evidence based to reduce safety concerns
• difficulty obtaining informed consent if knowledge of medical trials is poor
• using insecticide kills other organismss

Question 15

suggest the social and economic implications f controlling endemic malaria

Answer 15

• expensive to implement, especially since may affect countries have low GDP
• cost could be spent on other initiatives

Question 16

suggest the practical difficulties of controlling endemic malaria

Answer 16

widespread endemic
2 hosts involved
high antigen variability
parasite enters host cells, which shields it from immune response

Question 17

explain the role of scientific community in controlling malaria

Answer 17

develop and test evidence based treatments
develop accurate diagnostic tools to avoid overuse of expensive drugs