Trypanosoma

Question 1

What are the African trypanosome species?

Answer 1

Trypanosoma brucei gambiense (West Africa) & Trypanosoma brucei rhodesiense (East Africa).
RARELY Trypanosoma brucei brucei (normally does not affect humans)

Question 2

What is the American trypanosome species?

Answer 2

Trypanosoma cruzi

Question 3

What is the common name for African Trypanosome disease and where is it found?

Answer 3

sleeping sickness. not found in deserts but in the surrounding areas in Africa

Question 4

What is the vector for the African Trypanosomes?

Answer 4

tsetse fly, genus Glossina

Question 5

how are the two species differentiated?

Answer 5

they are morphologically different

Question 6

What does Trypanosoma brucei brucei do?

Answer 6

• African ruminants as host
• causing nagana, a type of sleeping sickness in animals
• reduces growth rate, milk productivity & strength, leading to eventual death
• very difficult for farmers

Question 7

How are the equine and camel trypanosomes different?

Answer 7

T equinim, T equiperdum, and T evansi are transferred by blood contact during copulation or by other biting insects that probe animals for blood (ex horse flies).
more widespread disease bc outside tsetse fly range

Question 8

What are the preferred hosts for each trypanosoma species?

Answer 8

T brucei gambiense: prefer humans but also infect pigs & other animals
T brucei rhodesiense: prefer wild animals but will also infect humans

Question 9

How else can the parasite be transferred?

Answer 9

• across the placenta
• blood transfusion
• sexual contact (rare)
• lab accidents

Question 10

Which species causes the chronic condition?

Answer 10

Tb gambiense (central & western Africa). can take time for symptoms to emerge

Question 11

Which species causes the acute condition?

Answer 11

Tb rhodesiense (southern & eastern Africa). emerges in a few weeks, develops quickly and is more virulent

Question 12

How does Trypanosoma evade the host immune system and how does this work?

Answer 12

Antigen Variation

• uses variant surface glycoproteins (VSGs)
• covers itself with VSGs
• when attacked, changes VSGs
• has over 1000 vsg genes

Question 13

What is the pathogenicity of Tb gambiense?

Answer 13

invades the central nervous system
causes apathy, mental dullness, tremor of hands, lethargic tongue. followed by convulsions and paralysis
followed by coma and death

Question 14

What is the pathogenicity of Tb rhodesiense?

Answer 14

does not attack the nervous system
causes rapid death after weight loss and heart involvement
winterbottom’s sign= swelling of lymph nodes along the back of neck

Question 15

How is sleeping sickness diagnosed?

Answer 15

detection of trypomastigote (only found in humans) from lymph node, blood, bone marrow or cerebral fluid. observe motile parasites, then fix and use giemsa stain

Question 16

How is sleeping sickness treated?

Answer 16

Pentamidine (West) & suramin (East) treat the hemolymphatic stages
melarsoprol treats the late disease with central nervous system involvement

Question 17

Where does Tb gambiense deposit its larvae?

Answer 17

moist areas along rivers. a bit easier to control

Question 18

Where does Tb rhodesiense & brucei deposit their larvae?

Answer 18

in dry soil. more difficult to control

Question 19

How can both trypanosoma brucei be controlled?

Answer 19

chemical spraying, elimination of wild game, selectively breeding cattle

Question 20

What is the name of the disease caused by Trypanosoma cruzi?

Answer 20

Chagas disease

Question 21

What is the vector species of Trypanosoma cruzi?

Answer 21

triatomine bugs (aka kissing bug) belonging to Triatoma, Rhodinius and Panstrongylus

Question 22

How else can chagas disease be transmitted?

Answer 22

• blood transfusions
• organ transplants
• transplacentally
• lab accidents

Question 23

How does the triatomine bug transfer the parasite?

Answer 23

takes a blood meal, then defecates. parasite is carried in feces
different species defecate at different times and can have different chances of transmitting the disease

Question 24

How are animal affected?

Answer 24

also get bit, but often do not get the disease

Question 25

What is the pathogenicity of Trypanosoma cruzi?

Answer 25

manifests in hollow organs and causes cell death because of parasite replication. may infect individuals for life
heart is often infected and can cause serious problems if blood vessels rupture

Question 26

What is Romana’s sign?

Answer 26

a marker of acute chagas disease. swelling of the eyelid due to feces getting rubbed into the eyes

Question 27

What are some symptoms of Chagas disease?

Answer 27

early: local swelling
late: heart disease, malformation of intestines. fatal

Question 28

What occurs in the chronic phase?

Answer 28

immunity to re-infection but parasites still present and cause problems including cardiomyopathy, megaesophagus, megacolon. can also be asymptomatic

Question 29

How can Chagas disease be diagnosed?

Answer 29

identification of amastigotes or trypomastigotesvia blood smears (thick & thin using giemsa. common) or biopsies (less common)

Question 30

How is Chagas disease controlled?

Answer 30

no vaccine
insecticides & improving house sanitation. paint house with insecticides
mosquito nets
testing blood before transfusion