Parasite Vaccines & Molecular Diagnostics

Question 1

3 main classifications of parasites

Answer 1

protozoa - microscopic one-celled organisms
helminths - nematodes, trematodes, cestodes
ectoparasites - ticks, fleas, lice, mites

Question 2

heirloom parasties

Answer 2

inerited form primary ancestors

Question 3

souvenir parasites

Answer 3

acquired through contact w animals (migration and agriculture; trravel)

Question 4

neglected tropical diseases helminth

Answer 4

taeniasis/cysticerosis
Guinea worm disease
Echinococcosis
foodborne trematodiases
lymphatic filariasis
soil-transmitted helminthiases
schistosomiasis
onchocerciasis

Question 5

prozoan neglected tropical diseases

Answer 5

Chagas
Leishmaniasis
human adrican trypanosoiasis

Question 6

extoparasitic neglected tropical diseases

Answer 6

scabies
other exctoparasites

Question 7

NTDs

Answer 7

• not a lot of funding
• neglected tropical diseases
• largely preventrable and treatable through efficient delivery of drug treatment, clean drinking water, eradication of vectors, etc.

Question 8

vaccine against malaria

Answer 8

RTSS/AS01
- >/= 5 months
- Plasmodium falciparum
- Abs against circumsporozoite
- protection short-lived; waning immunity
- transmission unchanged; does not target gametocytes (sexual stage) so children will still carry infection to innfect mosquitoes = does not change population transmission

Question 9

GVAP

Answer 9

global vaccine action plan
- prevent mmillionso f deats by 2-2- through more equitale access to existing vaccines for people in all communities
- WHO; enjoy lives free from vaccinep reventable diseases

Question 10

types of vaccines

Answer 10

inactivated : killed version; Hep A, Rabies, flu

live-attenuated: weakened version; MMR

mRNA vaccinesL proteins triggering immune response; COVID-19

subunit, recombinantr, polysaccharide and conjugate vaccines: pieces; S. pneumoniae, Hep B, HPV

toxoid vaccines: toxin iteself; Dip, tetanus

Viral vector vaccines: modified virus to eliver protection; ebola; COVID-19

Question 11

parasite vaccines

Answer 11

no other effective vaccine against human parasitic infections
- parasites = diverse strategies for immune evasion
- must elicit a response that outperforms naturally acquired immunity

Question 12

what does RTS,S/AS01 target?

Answer 12

pre-erythrocytic, blood, and mosquito stages of parasite

Question 13

Leishmania sp vaccine

Answer 13

prophylactic
therapeutic
- currently in development target different species, proteins, strains, etc.

Question 14

hookworm vaccines

Answer 14

phase 1 clinical trials
- 3 different vaccines
- target larval or adult stage

Question 15

Schistosoma vaccines

Answer 15

target different proteins or lifecycle stage

Question 16

serology

Answer 16

antigen detection, Ab detection, hemagglutination, immunofluorescence, etc.

Question 17

molecular-based approaches to diagnose parasitic infections that are faster and more accurate

Answer 17

real time PCR, loop-mediated isothermial amplification
sequencing
proteomics

Question 18

why is microscopy still so common today for looking at parasitic infections?

Answer 18

• cost-effective, variety of samples
• ISSUES: time-consuming, labour intensive, staff with specific expertise

Question 19

when to use serology based assays

Answer 19

when direct exam microscopy not possible (chronic phase of infection = no longer presenting symptoms)

similar TAT to microscopy

more sensitive and specific

highest yield:
- microscopy inconclusive
- low parasitemia/asympt
- low egg production/sporadic nature
- monitoring of parasite clearance

Question 20

end point PCR

Answer 20

low throughput analysis of 1 target in a single-closed tube
- Leishmania PCR

Question 21

ENDPOINT PCR BENEFITS

Answer 21

• SIGNIFICANT COST SAVINGS
• MODERATE TATS
• MODERATE LABOUR INTENSITY
• INCREASED SENSITIVITY

Question 22

real time PCR

Answer 22

• high throughput analysis of 1+ targets in a single closed tube reaction
• allows for quantification of original template NAs through various fluorescent chemistry
• ex: Malaria PCR confirmation

Question 23

benefits of real time PCR

Answer 23

• significant cost savings
• rapid TAT
• can witness in real time; no need for elctorphoelectrophoresisresis
• less labour intensive
• increased sensitivity

Question 24

Sanger sequenecing

Answer 24

• rapid high throughput sequencing of gnomes to be carried out in single instrument
• low per nucleotide sequencing cost
• limited use = research
  > limited databases
  > genome size
• potential for novel strain typing, molecular epidemiology and antimicrobial resistance

Question 25

whole gneome sequencing

Answer 25

• deep sequencing or massively parallel sequencing
• millions of DNA fragments sequenced simultaneously
• rapid and high throughput sequencing of genomes on a single instrument; low per nt sequencing cost
• not currently used for routine clinical diagnostics of parasites

Question 26

2nd generation sequencing platforms

Answer 26

roche 454
illumina MiSeq

Question 27

3rd generation sequencing platforms

Answer 27

• no PCR step
  Pac Bio
  Oxford Nanopore

Question 28

steps in 2nd gen whole genome sequencing

Answer 28

library prep
PCR
sequencing
data analysis

Question 29

proteomics

Answer 29

biomarkers for tissues, cell types, developmental stages and disease states

biggest advancement is the introduction of mass-spec platforms
- heavily used in mycology and bacteriology
- less so in virology and parasitology

Question 30

MALDI-ToF MS

Answer 30

analyzing protein composition to produce unique signature for ID at species level

Question 31

CDC equivalent of Canada

Answer 31

NCRP
national reference centre for parasitology

Question 32

NCRP blood born parasite ID techniques

Answer 32

microscopy for all but Toxoplasmosis
(but CDC still uses microscopy)

Question 33

current gold std for diagnosing parasite infection

Answer 33

serology and microscopy