Hemoflagellates

Question 1

Hemoflagellates

Answer 1

in blood, lymph, or tissue spaces of vertebrates; in intestinal tract of blood-sucking invertebrates

Question 2

Trypanosoma (morphology)

Answer 2

elongated, spindle-shaped cell with a single central nucleus and a single flagellum from the anterior end

Question 3

Trypanosoma cruzi (common name)

Answer 3

Chaga’s Disease

Question 4

Trypanosoma cruzi (final host)

Answer 4

Man, dog, cat, opossum, armadillo, rodents, etc.

Question 5

Trypanosoma cruzi (IM host)

Answer 5

Reduviid bugs – feed at night on sleeping hosts and deposit feces carrying T. cruzi at feeding sites – organism rubbed into feeding site or mucous membranes

Question 6

Trypanosoma cruzi (location)

Answer 6

Western hemisphere, esp. South America, Central America – also Mexico – few cases in the U.S. – mostly in southern states, including Louisiana, Texas

Question 7

Trypanosoma cruzi (acute phase)

Answer 7

Most common in children < 5 yrs. of age Heart muscle likely invaded
Symptoms include anemia, weakness, chills, fever, nervous disorders, muscle/bone pain, heart failure Death +/-

Question 8

Trypanosoma cruzi (chronic phase)

Answer 8

Primarily peripheral and central nervous system dysfunction
Heart failure, megaesophagus, megacolon
(#1 cause of human myocarditis worldwide)

Question 9

Trypanosoma cruzi (transmission)

Answer 9

Poor quality housing – good site for bugs
Reservoirs, esp. dog and cat
Eating bugs: believed aphrodisiacs in some areas of Mexico
Human to human:
Placental
Blood transfusions
Others unknown

Question 10

Trypanosoma lewisi:

Answer 10

Hosts in U.S.: Rats; mice
Vector: Northern rat flea
Pathogenesis: usually non-pathogenic
Importance: in research

Question 11

Trypanosoma theileri

Answer 11

Hosts in U.S.: Cattle
Vector: Horse flies (Tabanid flies)
Pathogenesis: Harmless unless stressed
Usually not seen in blood smears; requires cultivation

Question 12

Trypanosoma brucei

Answer 12

Vector:  Tse tse fly
3 subspecies (African)
A.  T.b. brucei – “Nagana”
Parasite of native ruminants – antelope, etc. –  non-fatal
Parasite of domestic livestock – sheep, goats, oxen, horses, dogs, etc. – produces disease often fatal within 2 wks – 4 mo
Economically important because
   4.5 million square miles which 
   could support livestock 
   are affected

Question 13

African Sleeping Sickness

Answer 13

Transmission: Tse tse fly – different species
Pathogenesis: sore at inoculation site  parasitemia  organs  swollen lymph nodes, pain, headache, weakness
T.b.r. – more acute deaths
T.b.g. – chronic sleeping sickness – signs may develop months-years after initial infection tremors, convulsions, paralysis, coma, death
Treatment: Older tx – arsenicals; newer drugs satisfactory in early cases, before neuro signs
Control: Tse tse fly control difficult

Question 14

Trypanosoma equiperdum – “Dourine” (host and transmission)

Answer 14

Hosts: Horses/donkeys
Transmission: by breeding

Question 15

Trypanosoma equiperdum – “Dourine”

clinical signs

Answer 15

Clinical stages:
Edematous genitalia/discharges
Rash on sides of body – “silver dollar plaques” – 3-4 day duration
Paralysis – neck/nostrils  hind body  generalized –fatal unless treated
Distribution: Africa, Asia, parts of Europe, Mexico
Eradicated from U.S. in 1949. Horses entering U.S. tested prior to entry.

Question 16

Family Trypanosomitidae

Genus Leishmania

Answer 16

Hosts: Mammals, esp. humans, dogs, rodents
Rodents may serve as reservoir hosts for zoonosis
IH/Vectors: Sand flies
Geographic distribution:

Question 17

Family Trypanosomitidae
Genus Leishmania
(pathology)

Answer 17

L. major
Cutaneous ulcers; heal within year if no
2° infection
Asia, Africa

L. donovani
Dum-dum Fever or Kala-azar (Visceral Leishmaniasis)
Disease of the reticulo-endothelial system
Asia/Africa

Treatment:
Antimony compounds; some resistance developing
One new drug (miltefosine) FDA approved in 2014 for visceral
leishmaniasis in adolescents and adults not pregnant or breast-feeding