the body's defenses

Question 1

all pathogenic prokaryotes known to date are archaea/bacteria

Answer 1

bacteria

Question 2

bacteria cause what fraction of all human diseases

Answer 2

1/2

Question 3

some bacterial diseases are transmitted by other species such as…………..

Answer 3

ticks and fleas

Question 4

prokaryotic pathogens usually cause illness by producing what

Answer 4

poisons

Question 5

what are the 2 classes of poison

Answer 5

endotoxin

exotoxin

Question 6

what is an exotoxin

Answer 6

a toxic protein that is secreted by a prokaryote or other pathogens that produces specific symptoms even if the pathogen is no longer present

Question 7

what is an endotoxin

Answer 7

a toxic component of the outer membrane (lipopolysaccharide) of certain gram negative bacteria that is released only when the bacteria die

Question 8

how can horizontal gene transfer transform normally harmless bacteria into pathogens

Answer 8

horizontal gene transfer can spread genes associated with virulence e.g. E.coli is normally harmless but a pathogenic strain has evolved

Question 9

what are the 3 types of symbiosis

Answer 9

mutualism
commensalism
parasitism

Question 10

what are chemoautotrophic bacteria

Answer 10

they harvest chemical energy from compounds such as hydrogen sulphide e.g. in a hydrothermal vent

Question 11

what are arthropods

Answer 11

segmented bodies with a hard exoskeleton and jointed appendages e.g. insects, spiders, crabs, lice and fleas

Question 12

do arthropods have an open or closed circulatory system

Answer 12

open

Question 13

what are zoonotic pathogens

Answer 13

those that are transferred to humans from other animals either through direct contact with an infected animal or by means of an intermediate species called a vector

Question 14

give examples of parasites that spread zoonotic diseases

Answer 14

ticks, lice and mosquitos

Question 15

why is identifying the dominant host for a pathogen important

Answer 15

you can then target the host to control spreading of the disease

Question 16

for a particular locus, which genotype has the greatest fitness

Answer 16

heterozygotes

Question 17

what is an epidemic

Answer 17

a general outbreak of disease with higher incidence than would normally be expected for a particular geography or population

Question 18

what is an endemic

Answer 18

the constant presence and/or usual prevalence of a disease for a particular geography or population

Question 19

what is a pandemic

Answer 19

a global epidemic spreading across continents

Question 20

which human behaviours in history have influenced epidemic disease

Answer 20

exploration
changes in patterns of trade 
warfare 
famine 
poverty, overcrowding and poor living conditions

Question 21

how have human behaviours influenced epidemic disease

Answer 21

they brought the opportunity for infectious agent to expand beyond its original ‘disease pool’ with devastating effect

Question 22

what was the black death

Answer 22

Bubonic plague - the first pandemic

Question 23

what organism carried the bubonic plague

Answer 23

fleas

Question 24

how did the fleas infect humans with the plague

Answer 24

they jumped from black rats to humans

Question 25

what type of transmission does the plague fall under

Answer 25

zoonosis - jump from one species to another

Question 26

what are symptoms of the plague

Answer 26

gangrene of extremities rapid onset and appearance of buboes infection of the lymphatic system

Question 27

what id the vector species in plague transmission

Answer 27

infected fleas

Question 28

what bacterium causes plague

Answer 28

Yersinia pestis

Question 29

how can plague be treated

Answer 29

with antibiotics unless the strain is resistant

Question 30

how can plague be prevented

Answer 30

pest control (rod of the rats)

Question 31

how is small pox spread

Answer 31

by droplets

Question 32

what are the symptoms of small pox

Answer 32

high fever and flu like illnesses | rash - infectious pustules

Question 33

what are the two types of influenza

Answer 33

A and B

Question 34

which type of influenza has caused pandemics

Answer 34

A

Question 35

which influenza A antigen is important for binding to the host cell

Answer 35

hemagglutinin

Question 36

which influenza A antigen is important for release from infected cell

Answer 36

neuraminidase

Question 37

why does influenza A cause pandemics

Answer 37

antigenic drift - caused by gene mutation and antigen variation

Question 38

what is Spanish flu

Answer 38

bird to human transmission of the avian virus

Question 39

what type of transmission does the Spanish flu show

Answer 39

zoonosis

Question 40

how is syphilis spread

Answer 40

by sexual contact - can result in still birth or deformities

Question 41

how is syphilis treated

Answer 41

penicillin injection

Question 42

which disease is known as the disease of war and famine

Answer 42

typhus

Question 43

what is typhus caused by

Answer 43

an obligate intracellular bacterium

Question 44

how are typhus bacterium transmitted to humans

Answer 44

via body lice

Question 45

what are symptoms of typhus

Answer 45

fever, chills, headache, muscle pain, confusion, rash

Question 46

what is typhus treated with

Answer 46

antibiotics

Question 47

are typhoid fever and typhus the same thing

Answer 47

NOOOOOOOOOOOOOO!!!!!

Question 48

what is typhoid fever caused by

Answer 48

salmonella typhi bacterium | it has to be ingested

Question 49

how can salmonella typhi be ingested

Answer 49

water contaminated with faecal matter

Question 50

what are typhoid fever symptoms

Answer 50

headache, fever, abdominal pain (enlarged spleen/liver), diarrhoea/constipation, rash

Question 51

how can typhoid fever be controlled

Answer 51

safe drinking water proper sewage disposal antibiotics vaccines

Question 52

what are the virulent factors of the typhoid life cycle involved in

Answer 52

in symptom development and immune evasion

Question 53

what bacteria causes cholera

Answer 53

vibrio cholerae - when ingested from faecal matter

Question 54

how many types of vibrio cholerae cause disease

Answer 54

2

Question 55

what is the natural habitat of vibrio cholerae

Answer 55

freshwater, brackish and coastal-water habitats

Question 56

what is the action of vibrio cholerae

Answer 56

it produces a toxin that modifies a g protein involved in slat and water regulation cAMP is continuously made resulting in intestinal cells secreting a large amount of salts into the intestines along with water by osmosis causing major diarrhoea

Question 57

how can cholera be controlled

Answer 57

safe drinking water proper sewage disposal antibiotics vaccines

Question 58

what is polio

Answer 58

Illness through gastrointestinal infection by poliovirus

Question 59

what does the poliovirus do

Answer 59

replicate in motor neurons if invade CNS

Question 60

how is poliovirus transmitted

Answer 60

mainly through contact with faeces

Question 61

what are the 2 types of polio vaccine

Answer 61

sabin and salk

Question 62

what are the sabin vaccines made of

Answer 62

attenuated viruses

Question 63

what are the salk vaccines made of

Answer 63

inactivated vaccine (used in UK since 2004)

Question 64

what is TB caused by

Answer 64

Mycobacterium tuberculosis (MTB)

Question 65

TB has a latent form, what does this mean

Answer 65

it is non infectious at this stage

Question 66

how is TB spread

Answer 66

person to person through air

Question 67

what are symptoms of TB

Answer 67

cough, night sweats, chest pain, coughing up blood/mucous

Question 68

what are treatments for TB

Answer 68

6 month course of antimicrobial drugs

Question 69

what are methods of TB prevention

Answer 69

vaccination

Question 70

what is the treatment for HIV

Answer 70

lifelong drug treatment - no cure

Question 71

what is a parasite

Answer 71

‘A parasite is an organism living in or on another living organisms, obtaining from it part or all of its organic nutrition, commonly exhibiting some degree of adaptive structural modification and potentially causing some degree of damage to its host

Question 72

what is prevalence

Answer 72

the proportion of a population infected (e.g.3%)

Question 73

what is incidence

Answer 73

• Incidence – the proportion infected in a unit of time i.e. the number of new infections e.g. 3% per week

Question 74

what is intensity

Answer 74

the number of parasites per host

Question 75

what is mortality

Answer 75

the number of deaths in a unit of time

Question 76

what is morbidity

Answer 76

the amount of ill – health/disability in a unit of time

Question 77

what is DALY

Answer 77

Disability adjusted life year – a measure of overall disease burden. The number of years of lost to ill health, disability or early death

Question 78

what are ectoparasites

Answer 78

live on the organism e.g. lice

Question 79

what are endo parasites

Answer 79

live in the organism e.g. tapeworms, toxoplasma gondii

Question 80

what are NTDs

Answer 80

neglected tropical diseases - diseases that cause substantial illness for more than one billion people globally.

Question 81

what are examples of NTDs

Answer 81

schistosomiasis

Question 82

infection rates and disease burdens of NETs are greatest where

Answer 82

poorest communities lacking infrastructure and sanitation.

Question 83

what are ascaris lumbricoides

Answer 83

round worms

Question 84

what can ascaris lumbricoides be treated with

Answer 84

Oral albendazole, mebendazole and/or Ivermectin

Question 85

How is schistosomiasis transmitted

Answer 85

in water

Question 86

what is the cycle of schistosomiasis

Answer 86

``` parasitic eggs in water larvae hatch and infect snails - the vector larvae released into water penetrate human skin larvae mature into worms cause liver problems worms lay eggs that cause damage eggs released into water via urine or faeces ```

Question 87

how to cure schistosomiasis

Answer 87

using drugs

Question 88

prevention of schistosomiasis

Answer 88

treatment of breeding snails

Question 89

what is the plasmodium life cycle

Answer 89

``` transmission to human via mosquito bite sporozoites enter liver and infect hepatocytes liver cells rupture sexual cycle mosquito ingests gametocytes sporozoites develop ```

Question 90

why don't we have vaccines for schistosomiasis and malaria

Answer 90

* Complex life cycles, with multiple stages in different tissues * High level of antigenic variation, e.g. blood stage malaria * Multiple immune evasion strategies (eg sequestration) * Parasites are able to suppress the immune system