Plasmodium gallinaceum: density dependent limits on infectivity to Aedes aegypti |
| |
Authors: | R Rosenberg L C Koontz |
| |
Affiliation: | Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20205, U.S.A. |
| |
Abstract: | In acute, blood-induced infections of chickens, the malarial parasite Plasmodium gallinaceum is most infective to the mosquito Aedes aegypti 1 day before gametocyte numbers peak. In an effort to account for this disynchrony , daily changes in parasite infectivity, parasitemia, hematocrit, and hemoglobin were measured during the course of infections. Three events were correlated with the loss of infectivity: (1) In the 24 hr between park infectivity and peak gametocytemia , schizont-induced hemolysis reduced the red blood cell volume 22%. (2) P. gallinaceum zygotes, fertilized in vitro and mixed with heavily infected red blood cells from which all viable, mature gametocytes had been removed, produced 67% fewer oocytes than when combined with uninfected red blood cells. (3) Zygotes fertilized in vitro on the day of peak parasitemia produced 47% fewer oocysts than zygotes prepared 24 hr earlier. It appears that high parasite density reduces infectiousness by destroying, through hemolysis and intraerythrocytic metabolism, a substance necessary to the sporogonic stages, and that there is also an intrinsic loss of infectivity, possibly due to decreased efficiency of fertilization. |
| |
Keywords: | Protozoa, parasitic Malaria, avian Infectivity Chicken Hemoglobin Erythrocyte Mosquito infection |
本文献已被 ScienceDirect PubMed 等数据库收录! |
|