Triatomine bugs and trypanosoma cruzi

Question 1

Trypansoma cruzi lifecycle

Answer 1

A. Dividing epimastigotes.
 B. Infective metacyclics.
 C. Excreted infective metacyclics.
 D. Host cell infection.
 E. Circulating trypomastigotes.
 F. Pseudocyst containing dividing amastigotes.
 G. Ingestion of trypomastigotes by insect vector.

Question 2

Chagas disease

Answer 2

Endemic in South and Central America
- 11m infected, 13,000 deaths a year
-~30% of patients develop chronic disease
-Damage to cardiac or digestive organs
- Variation in outcome:
 Between individuals
 Between regions

Question 3

Xenodiagnosis

Answer 3

using triatomine bugs with no infection to suk up blood of infected animals

Question 4

Tiatomine bugs

Answer 4

Order - hemiptera
family - reduviidae
subfamily - triatimonae
Two main species - Triatoma infestans - southern cone and rhodnius prolixus - central america

Question 5

Noireau traps

Answer 5

Pots with a mouse in and wire gausse on top

place in shrubs and burrows

Question 6

caharcteristics of traitomines that make the vulnerable to control

Answer 6

Low capacity for active dispersal
Low genetic diversity within populations
All life stages present in houses
slow reproducing - k strategists

Question 7

separate transmission

Answer 7

domestic and sylvatic cycle are separate

Question 8

overlapping transmission

Answer 8

eg. Rhodnius prolixus - live in palm trees and domestic homes

Question 9

Lineages of traitomines

Answer 9

TC 1 - Didelphis Rhodnius spp Palm trees
TC II - Domestic
TC III -armadilllos
TC IV Human acute/ mainly sylvatic
TC V -Domestic - T. infestans
TC VI - Domestic

Question 10

Why vector parasite interactions important?

Answer 10

To identify what factors contribute to the establishment of trypanosomes in the gut of the invertebrate host

Question 11

Infection of bug with T.cruzi

Answer 11

• Begins with the arrival of an infected blood meal in the insect gut
• Trypomastigotes transform into epimastigotes
  In the intestine, divide by binary division and can attach to the peri-microvillar membranes in the intestinal cells
• At later stages in the rectum, a proportion of the epimastigotes attach to the rectal cuticle and transform into metacyclic trypomastigotes eliminated with the feces and urine and are able to infect the
  vertebrate host

Question 12

Factors effecting T. cruzi vector interactions

Answer 12

Gut and hemolymph molecules
-Organization of midgut epithelial cells on the parasite
development
-Vector insect’s permissiveness to T. cruzi
-which develops in the vector gut, largely depends
on the host nutritional state
-parasite strain
- molecular interactions with trypanolytic
compounds
-lectins and resident bacteria in the gut

Question 13

microbiota of triatomine bugs

Answer 13

Arsenophonous appeared as
the dominant triatomine bacterial
symbiont
-Trypanosoma cruzi-challenge significantly
affects microbiota composition

Question 14

T. rangeli

Answer 14

related to T. cruzi
doesnt infect humans
only infects Rhodnius species
different cos penetrate haemocoel and migrate to salivary glands
once in haemolymph activates the immune responce of the vector

Question 15

LEXY system

Answer 15

can sequence T.cruzi
introduce plasmids with flourescent genes to parasites so can see where they attach
parasites would hybridise inside and show both colours

Question 16

CRISPER -Cas 9

Answer 16

cutting enzyme - flanked by a guide RNA so can target genome and cut it anywhere
could use for attachment of parasites