3.1 Microbial Infection

Question 1

What are the main types of infectious agents causing disease in humans

Answer 1

Virus
Bacteria
Protozoa
Fungi
Helminths

Question 2

How do virus replicate

Answer 2

Using host cell nuclear machinery and divide by budding out of cell or cytolysis

Question 3

Example of a virus

Answer 3

Retrovirus - HIV

Variolavirus - small pox
Poliovirus - polio

Question 4

Viruses

Answer 4

Obligate parasites

DNA/ RNA

faecal oral, bloodborne, airborne, insect vectors

Question 5

RNA to DNA

Answer 5

Requires reverse transcriptase

Question 6

How do bacteria replicate

Answer 6

Binary fission

Question 7

Example of bacterial infection

Answer 7

Shigella species - shigella

Neisseria meningitidis - meningitis

Mycobacterium tuberculosis - TB

Question 8

Shigella

Answer 8

Bacterial infection by shigella species

Faecal oral route if transmission

GI tract

Cell to cell spread using host actin

Question 9

Meningitis

Answer 9

Bacterial by neisseria meningitidis

Rapid progression, septic shock, severe inflammatory response

Seen as septicaemia then meningitis in CSF

Question 10

Nosocomial infection

Answer 10

Hospital acquired

E.g. clostridium difficile and MRSA

Question 11

How do fungi replicate

Answer 11

Yeast bud or divide

Filaments cross walls or septa

Question 12

Example of a fungi

Answer 12

Candida albicans in gut

Question 13

Fungi

Answer 13

Eukaryotic as yeasts or filaments

Cause cutaneous, mucosal or systemic mycoses

Question 14

How do Protozoa divide

Answer 14

Replicate in host by binary fission or formation of trophozoites in a cell

Question 15

Example of Protozoa

Answer 15

Plasmodium species - malaria

Leishmania species - leishmaniasis

Question 16

Protozoa

Answer 16

Unicellular eukaryotic

Intestinal blood and tissue parasites

Infection by ingestion or through a vector

Question 17

Malaria

Answer 17

Plasmodium species via female anopheles mosquito vector

Blood and tissue parasites

Formation of trtophozoites inside a cell

Question 18

Leishmaniasis

Answer 18

Leishmania species via a sandfly vector

Blood and tissue parasites

Formation of trophozoites inside a cell

Cutaneous and visceral disease

Question 19

How do Helminths divide

Answer 19

Life cycle outside the human host

Question 20

Example of Helminths

Answer 20

Round worms

Flatworms (flukes)

Tapeworms

Question 21

Helminths

Answer 21

Multicellular eukaryotes

Visible to naked eye

Question 22

Effective treatment of infections require

Answer 22

Knowledge of the causative agent

Source and mode of transmission and how they cause damage and how the body reacts to it

Question 23

Prevent infection

Answer 23

Vaccine

Question 24

Treat infection

Answer 24

Drugs