Neglected tropical diseases 4 Flashcards
What causes chagas disease?
parasitic protozoan–> Trypanosoma cruzi
Which organism spreads T. Cruzi?
Kissing bugs
Where is chagas disease mainly seen?
Continental latin american countries
Non insect methods of chagas disease transmission?
Blood transfusion, oral, congenital
Two phases og chagas disease?
Acute and chronic
How is chagas disease prevented?
Insectisides and bed nets
How is chagas disease treated?
anti-parasitic medication, benznidazole and nifurtimox
Effectivity of chagas treatment over time?
Decreases over time
Three forms of T.Cruzi?
Trypomastigotes, amastigotes, epimastigotes
Replicative forms of T. Cruzi?
Epimastigotes and amastigotes
Where are epimastigotes found?
Insect midgur
Where are amastigotes found?
Mammalian cells
Where are trypomastigotes found?
Insect vector and bloodstream of human host
Features of trypomastigotes?
Non-proliferative but can infect new cells
Where do triatomine bugs usually bite?
Face/mouth
What happens after the triatomine bug bites on the face/mouth?
T.cruzi enters the human bloodstream via the wound site
Where in the triatomine bug is T.Cruzi found?
The faeces
What happens to trypomastigotes after they have infected a cell near the bite wound?
They transform into an amastigote
What happens once amastigotes are formed?
They multiply by binary fission in the cells of the infected tissue
What causes localised swelling at the wound site of the T.cruzi infection?
Binary fission of amastigotes in the cells of the infected tissue
What happens to amastigotes once they have replicated via binary fission?
They transform into trypomastigotes, and burst into the bloodstream
What can trypomastigotes do once in the bloodstream?
Travel to new infection sites, where they transform into amastigotes b4 replicating again
What occurs in the new infection sites?
Massive swelling
What happens if another triatomine bugs bites someone infected with T.Cruzi?
It ingests t.cruzi
What happens to trypomastigotes once they enter the gut of the triatomine bug?
They transform into epimastigotes and multiply in the guts of the insect
Where do t.cruzi viruses transform from epimastigotes into trypomastigotes in the triatomine bug?
The hindgut
Pathogenesis of acute phase of chagas disease?
Fever, fatigue, body aches early on
Romana’s sign, chagomas, myocarditis later on
What is romanas sign?
Swelling on the eyelids, side of face near the bite would where the bug faeces were deposited and rubbed into the eye or wound site
What are chagomas?
Inflammatory nodules at the bite site caused by early T.Cruzi multiplication
What happens if the acute phase persists for longer than 8 weeks?
It enters the chronic phase
Presentation of chronic phase of chagas disease?
life threatening dilations of hert, nervous system and digestive system
What causes dilations of critical organs in chagas disease?
