Parasite polymorphism may serve to enhance fitness in different host environments.
Phenotypic expression of trans-sialidase (TS) by Trypanosoma cruzi (Silvio strain) is restricted to a subpopulation (20-30%) of broad trypomastigotes (TS+ parasites), while the larger subpopulation of slender trypomastigotes lacks TS expression (TS- parasites). Rhodnius prolixus nymphs were infected with fractionated T. cruzi parasite populations (Silvio strain). Bugs ingesting TS- parasites produced significantly higher parasite loads than bugs ingesting either TS+ parasites or unfractionated populations. The addition of 1.0 microg of TS monoclonal antibody (TCN-2)/ml of blood meal to TS+ populations increased parasite populations to levels comparable to those of TS- populations. In contrast, the addition of exogenous TS to TS- parasite blood meals significantly reduced parasite loads to levels comparable to bugs ingesting TS+ parasites. These results suggest that T. cruzi trypomastigote polymorphism may serve to enhance survival in different host environments.
Takano-Lee
Miwako
M
Department of Entomology, University of Massachusetts, Amherst, MA, USA. mtlee@ucdavis.edu
Edman
John D
JD
Herrera
Enrique M
EM
Tussie-Luna
Maria I
MI
Pereira
Miercio E A
ME
D000818:Animals; D014355:Chagas Disease / Q000469:parasitology / Q000635:transmission; D006023:Glycoproteins / Q000235:genetics* / Q000378:metabolism; D006790:Host-Parasite Interactions; D007303:Insect Vectors / Q000469:parasitology*; D009439:Neuraminidase / Q000235:genetics* / Q000378:metabolism; D009758:Nymph / Q000469:parasitology; D010641:Phenotype; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D011817:Rabbits; D012239:Rhodnius / Q000469:parasitology*; D014349:Trypanosoma cruzi / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development
D006023:Glycoproteins; C069715:trans-sialidase; D009439:Neuraminidase